Yale Scientific
Established in 1894
THE NATION’S OLDEST COLLEGE SCIENCE PUBLICAITON
November 2013
Vol. 86 No. 4
BIRTH OF
A STAR
PAGE 8
MEDICINE CURRENT EVENTS BIODIVERSITY
Geography of a
Gene
Regional variations in the
MIF gene are linked to the
dual HIV/TB epidemic
Fighting for
Funding
Recent cuts in federal
spending take a heavy toll
on scientific research
Gut
Revelations
Analyzing DNA inside fly
guts grows understanding
of rainforest biodiversity
PAGES 15-17 PAGE 27 PAGE 31
everyday Q&A
Q&A
Almost everyone has struggled with jet lag, but what are the actual causes behind it?
After flying halfway around the
world, even the most seasoned
traveler will succumb to drowsiness,
disorientation, and a strong
urge to fall asleep in the middle of
the day. As we struggle to adjust
to new time zones, we cannot
help but experience the sensation
known as jet lag — the sun in our
new location tells us what time of
day it is, but our brains often do
not process the switch for several
days.
Normally, the body’s internal
clock is programmed to respond
to light as a stimulus that keeps
us alert and awake. But when the
body suddenly shifts to a different time zone, something occurs
at the molecular level that prevents light from having its immediate
effect. This “something,” recently discovered by a group of
Q&A
What Causes Jet Lag?
In high school chemistry class, we learned that absolute zero is
exactly what its name suggests: the lowest possible temperature
that can exist, the threshold at which atoms lose all their kinetic
energy and stop moving. However, physicists recently created
an atomic gas that exists below this threshold, or at negative
temperatures.
The term “negative” is actually a bit misleading. “The gas is
not colder than zero Kelvin, but hotter,” explained Dr. Ulrich
Schneider, the lead physicist of the project. “It is even hotter
than at any positive temperature — the temperature scale simply
does not end at infinity but jumps to negative values instead.”
To explain the idea of negative temperature, the researchers
describe their system in terms of hills and valleys. At absolute
zero, atoms have no energy, and they are all at the bottom of
the valley. As temperatures increase, some particles gain enough
energy to move up the hill, but most remain at the bottom.
A temperature of exactly infinity is the balancing point. Here,
enough particles have left the valley and spread out evenly along
the hill’s slope. But past infinity, more particles are on the hill
than in the valley — the exact opposite of the distribution in the
positive temperature realm; this is what physicists call negative
temperature.
In their experiment, the researchers forced a gas into its
highest possible energy state, achieving a temperature of a few
BY MARIANA DO CARMO
IMAGE COURTESY OF SCRIPPS COLLEGE
Researchers at Oxford University have found that a protein
called SIK1 is at contributor to symptoms of jet lag.
researchers at Oxford University,
is actually a protein called
salt inducible kinase 1, or SIK1.
The protein acts as a “molecular
brake” on the effect of light
in the human body, inhibiting
certain genes in our DNA that
are activated by light and that
help the body adjust to different
time zones.
By reducing SIK1 activity in
mice, the research team found
that animals acclimated to time
zone changes in only a few
hours, whereas untreated mice
required six days to adjust. This
newfound understanding of the
molecular basis behind jet lag may lead to drugs that could help
minimize SIK1’s effect on humans — and maybe help us all enjoy
the first few days of travel a bit more.
Can Temperatures Ever Drop Below Absolute Zero?
Physicists can now push temperatures below what has been considered the lowest energy minimum.
BY AHMED ANSARI
IMAGE COURTESY OF LMU/MPQ MUICH
Scientists were able to reverse the distribution of atoms
at positive temperatures (blue), resulting in a negative temperature
system (red).
billionths of a Kelvin below absolute zero. Their work opens
up possibilities for the study of other high-energy systems that
would otherwise collapse.
2 Yale Scientific Magazine | November 2013 www.yalescientific.org
NEWS
5
6
6
7
Letter from the Editor
Joan Steitz Receives the Grande Médaille
Disease-Detecting Biosensors
Q&A with Physics Professor Reina
Maruyama
contents
November 2013 / Vol. 86 / Issue No. 4
ON THE COVER
7
9
10
11
Q&A with Physics Professor Michel
Devoret
Illuminating the Circuitry of the Brain
Small Molecules Designed to Fight Heart
Ischemia
54-Year-Old Mathematics Conjecture
Proven
FEATURES
27
28
30
31
32
33
34
35
36
37
38
Current Events
The Impact of Sequestration on Research
Oceanography
An Undiscovered World of Ocean
Viruses
Geology
Mega-Canyon Uncovered in Greenland
Ecology
Fly Guts Reveal Rainforest Biodiversity
Environment
Mythbuster: The Great Pacific Garbage
Patch
Neuroscience
Debunking Science: Near-Death
Experiences
Undergraduate Profile
Jan Kolmas, TC '14
Alumni Profile
Yenyen Chan, SY '94, F&ES '01
Ecology
Urbanization Boosts Animal Brain Size
Trivia
Five Things You Didn't Know about
Black Holes
Book Reviews
-Brilliant Blunders
-The Eternal Darkness
-Packing for Mars
8
12
15
Why does the TB/HIV dual
epidemic pervade Sub-Saharan
Africa? Dr. Richard Bucala's
research suggests that
genetics holds the answer.
18
Astronomers Examine the Process of Starbirth
Yale Professor Héctor Arce and an international collaboration of
astronomers have obtained striking images of a protostar, providing a
new glimpse into the dynamics of star formation.
The Future of
Space
Exploration
The rise of the space industry
holds great promise for
exploration. From asteroid
mining to X PRIZE, rockets
are just the beginning.
HIV & TB:
Understanding
the Epidemic
Targeting
Diabetes at
Its Source
A clinical trial led by Yale
Professor Kevan Herold
may enable an effective new
type 1 diabetes treatment.
Solute Influence
on Enzyme 23
Motion
Small molecules from buffers
can alter millisecond motions
of enzymes. The Loria lab
demonstrates how buffers
can confound experiments.
20
Glia
25
IMAGE COURTESY OF ALMA/ESO
IMAGE COURTESY OF COLON-RAMOS
& Growth: Uncovering the
Architecture of Synapses
IMAGES COURTESY Of BARAN SARAC
Optimizing Microstructures to
Enhance Durability
More articles available online at www.yalescientific.org
www.yalescientific.org
November 2013 | Yale Scientific Magazine 3
the future of space
The last time man stepped on the moon
was over 40 years ago. With manned
missions rapidly losing popularity in
recent years, where is space exploration
headed?
pg. 12
rediscovering the earth
Although our eyes may be trained on the
skies and the deep seas as the frontiers
of exploration, the surface of our earth
still has secrets it is slowly revealing to us.
pg. 30
“
The day we stop exploring is the
day we commit ourselves to live
in a stagnant world, devoid of
curiosity, empty of dreams.
— Neil deGrasse Tyson
”
microscopic sea worlds
The murky, seemingly endless depths of the oceans have
mesmerized mankind’s imagination for all of time. Until now,
however, we have been overlooking some of the greatest
worlds of diversity — those invisible to the naked eye.
pg. 28
FRONTIERS of EXPLORATION
November 2013 Volume 86 No. 4
Editor-in-Chief
Publishers
Managing Editors
Articles Editors
News Editor
Features Editor
Copy Editors
Online Editor
Production Manager
Layout Editors
Arts Editor
Webmaster
Multimedia Editor
Advertising Manager
Distribution Manager
Subscriptions Manager
Outreach Chair
Staff
Zoe Kitchel
Brendan Shi
Elizabeth Himwich
William Gearty
Jiahe Gu
Contributing Writers
William Ge
Somin Lee
Taryn Laubenstein
Sophie Janaskie
Payal Marathe
Yale Scientific
M A G A Z I N E
Established 1894
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Stella Cao
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Rebecca Su
Grace Cao
Dennis Wang
Walter Hsiang
Chanthia Ma
Carrie Cao
Christina de Fontnouvelle
Nicole Tsai
Jeremy Liu
Seung Yeon Rhee
Aurora Xu
Alex Co
Deeksha Deep
Naaman Mehta
Kevin Boehm
Emma Graham
Tierney Larson
Blake Smith
Ahmed Ansari
Ariel Ekblaw
Ethan France
Cathy Ren
Stephanie Mao
Edward Kong
Advisory Board
Sean Barrett, Chair
Physics
Priyamvada Natarajan
Astronomy
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Chemistry
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Child Study Center
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Computer Science
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Please send questions and comments to ysm@yale.edu.
F R O M T H E E D I T O R
Frontiers of Exploration
Exploration is without scope. It can encompass sparks of revolutionary invention
or revealing reexaminations of known fact. It can take us soaring up through clouds
and stars or deep down into the darkest depths of the ocean. It can be embodied by
Viking voyages hundreds of years past or even by a mission much closer to home: the
matriculation of modern-day university students.
On August 23, 2013, 1,359 Yale College freshmen bustled into new dorm rooms for
the very first time, greeted their suitemates, unpacked their suitcases, and settled in for
the long-haul. For many of these students, freshman year will be a bumpy ride. The
beginning of any journey can often be the longest, rockiest stretch of the road. But it can
also be an experience of excitement, of growth, and of great discovery.
Welcome to Issue 86.4 of the Yale Scientific. Thanks to our new freshman contributors
as well as our returning writers and artists, this issue’s articles will investigate a wide range
of scientific “Frontiers of Exploration,” from the microscopic inner workings of synapse
formation, to the far-away formation of stars. Two issues back, we published a collection
of articles on the theme “Limits and Breakthroughs,” focusing on the value of landmark
scientific discoveries. Our hope in this issue is to present a more panoramic perspective
on scientific research by covering news in science not just in terms of its end-results, but
in terms of the clever inquiry and exploratory work that goes into finding those endresults.
At a time when funds are few and far between in the United States, many scientists
who once had access to all the tools they needed to uncover and explore their way
to discoveries are starting to come up short. (See the article “Sequestration Cuts into
Scientific Research” on page 27). Now more than ever, the cost of scientific exploration
is steep. But its benefits are priceless, yielding improvements that sweep across society,
from cheaper health care alternatives to more efficient technologies.
Unexplored frontiers can be daunting, even for the boldest of explorers. Whether the
frontier in question happens to be a first year of college or a free market economy, it can
be difficult to maintain a steady direction forward in the face of obstacles. But science is
all about discovery through trial and error. With the common compass of science guiding
us onward, scientists and societies alike are empowered to strive toward discovery, to
delve into the unknown, and — perhaps most importantly — to find value in the process
of exploration along the way.
Jessica Hahne
Editor-in-Chief
About the Art
The cover, designed by Arts Editor Nicole Tsai, utilizes images
captured by the Atacama Large Millimeter/submillimeter
Array (ALMA), detailed in the article on page 8. A star chart
depicting the southern constellation of Vela (The Sails) was
overlaid on a second image of a rich region of dust clouds
and star formation in the southern constellation of Vela.
Images were provided by Yale Associate Professor Héctor Arce
and the European Organization for Astronomical Research in
the Southern Hemisphere. Contributing artists for this issue
were Rachel Lawrence (pages 4, 18), Lining Wang (page 12),
Lindsey Stavola (page 15), Nicole Tsai (pages 20-21), Casey
McLaughlin (page 23), Audrey Luo (page 25), Annelisa
Leinbach (pages 28-29), and Grace Pan (page 36). We would
like to correct the mispelling of an artist's name in Issue 86.3's
"About the Art": Kantiya Jindachomthong.
BIOCHEMISTRY
Joan Steitz Awarded the Grande Médaille
Joan A. Steitz, Sterling Professor
of Molecular Biophysics and
Biochemistry and Howard Hughes
Medical Institute Investigator, will
receive the 2013 Grande Médaille
from the French Academy of Sciences.
Each year, the Academy
bestows the Grande Médaille as its
highest honor to a French national
or foreign researcher who has
“contributed in some remarkable
and decisive way to progress in his
or her field.”
After obtaining her bachelor’s
degree in chemistry from Antioch
College in 1963, Steitz joined the
laboratory of James Watson at
Harvard University. There, she began her study of
ribonucleic acids (RNA). Throughout her career, she
has provided groundbreaking insights into the workings
of RNA. Most notably, since joining the faculty
at Yale in 1970, Steitz has shown that ribosomes bind
messenger RNA (mRNA) during translation through
BY CRISTAL SUAR
complementary base pairing and
that a class of non-coding RNA,
small nuclear ribonucleoproteins
(snRNPs), exists to splice
introns from mRNA following
transcription. With her group,
Steitz continues to discover what
she describes as “new, wonderful,
and sometimes bizarre
examples of how the power of
[RNA] base pairing controls and
sets the foundation for so many
things that go on inside cells.”
In addition to her pioneering
research, Steitz is also
recognized for promoting
the involvement of women
in science. When Steitz began her career, there were
few female role models in molecular biology. Steitz has
since become a prominent and respected leader in the SUBJEC
IMAGE COURTESY OF JOAN STEITZ
Sterling Professor Joan Steitz is
most recognized for her discoveries
involving RNA.
field. Regarding her Grande Médaille, Steitz hopes that
“whoever reads the publicity … sees that women are
making contributions just like men to science.”
ENGINEERING
Regenerative Biosensors Detect Disease Markers
The applications of nanosensors,
designed to identify target molecules
including disease markers, have
been limited by the fact that the
devices can only be used once. But
recently Dr. Mark Reed, Professor
of Electrical Engineering, has
led research creating electronic
biosensors that can be regenerated
and used repeatedly.
Biosensors, geared to detect
and measure disease markers
ranging from emergent cancer
signals to new types of infections,
are primarily used on blood and
water samples. Biosensors detect
particular indicators through
the binding of molecules onto
receptors that induce a change
in electric potential, allowing for rapid and accurate
medical diagnoses.
In traditional sensors, no further binding, sensing,
or usage is possible after a receptor has been bound.
However, Reed’s latest research, published in ACS Nano,
BY JONATHAN YU
introduces biosensors possessing
regenerative properties based
on a supramolecular approach,
in which a layer of receptors on
top of a sensor can be ripped
off through a “cleaning process”
and replaced by additional layers.
“[This] ‘Velcro’ layer system
allows for increased accuracy
and confidence in measurements,
since reusable biosensors can
be harnessed to run massive
multi-parallel experiments with
extreme precision,” said Reed.
The development of reusable
biosensors promises an
expansion in future applications
of biosensors, particularly in areas
involving continuous monitoring
and implantation. With contemporary improvements
unfolding in remote monitoring of toxins and biothreats,
regenerative biosensor technology holds the key
to even earlier and more accurate detection, diagnosis,
and treatment of diseases.
IMAGE COURTESY OF MARK REED
Biosensors detect disease by
sensing when certain molecules
bind to receptors. Traditional
biosensors can only be used once.
6 Yale Scientific Magazine | November 2013 www.yalescientific.org
q&a with
award-winning physicists
ECT
BY EDWARD KONG
Reina Maruyama, Assistant Professor of Physics, was
named June 2013 Woman Physicist of the Month by the
American Physical Society for her work in nuclear and
particle astrophysics and mentorship of young scientists.
What were your
thoughts when you
were named Woman
Physicist of the
Month?
I was nominated by
people I was mentoring,
so I felt honored that
those interactions I
had with students and
post-docs — that they
appreciated it, and that
they thought enough
to nominate me for this
award.
IMAGE COURTESY OF THE AMERICAN PHYSICAL
SOCIETY
How did you become
interested in research? Did you know what you wanted to
pursue early on, or did it take a lot of exploration?
I would say for me it was a journey. When I started undergraduate
studies I didn’t really know what I wanted to major in, so I pursued
physics as one option. I’ve always loved finding out how things
worked, and questions of why things are the way things are, how
we got here — that was always something that interested me.
What kind of advice would you give to undergraduates
interested in doing research, both in your field and in the
broader area of physics?
I would say, explore. Don’t be afraid to try new things; don’t be
afraid to fail. There’s so much cool stuff out there, and I really
encourage you to explore and see what gets you going.
What is it like to perform research internationally? Do those
roles and responsibilities ever make mentoring difficult?
A lot of neutrino and dark matter experiments are located in
remote locations such as underground laboratories. I think that
Antarctica has additional pull for students — just doing science in
crazy places. Having that extra motivation to get people interested
in what we do … I think that’s actually a plus. And if I can send
students there, that’s even better.
IMAGE COURTESY OF YALE APPLIED
PHYSICS
Michel Devoret is the
Frederick William Beinecke
Professor of Applied Physics
& Physics. He and Robert
Schoelkopf received the John
Stewart Bell Prize from the
University of Toronto for their
contributions to the field of
quantum mechanics.
What were your thoughts when you were awarded the John
Stewart Bell Prize?
This kind of recognition is always felt as a great honor, and a great
happiness to be admitted among physicists … it’s this feeling of
being included in a very interesting community.
What is it like to collaborate so closely with another researcher?
Rob is a wonderful criticizer. He’s pitiless and very harsh, and I
appreciate this very much. We collaborate in various ways, but this
kind of critical eye is very precious.
What made you interested in doing research? Did you know
early on that physics was the field you wanted to pursue?
I have known ever since I was 25 that I wanted to become a physicist
but prior to that, if I could have been a pilot, I would have. This was
my childhood dream. But then because my eyesight is rather poor, I
had decided to be an aviation engineer, but you see I ended up being
a physicist, because as you grow up you learn more about the world
around you, you understand better what science is, what the different
sciences are, and how you fit in.
What kind of advice would you give to undergraduates interested
in doing research?
Right now, we are not limited in my field by the laws of nature so
much as we are limited by our ability to interest young students to
join the field. So they can come en masse and there will be something
interesting for them to do.
What would you say is the coolest application of quantum
computing?
What’s interesting about quantum information [is] that it [can’t] be
copied … There will be more and more need for the privacy of
information as abuses are committed with information that circulates
on the web. There will be more and more desire to be able to control
where the information is going.
www.yalescientific.org November 2013 | Yale Scientific Magazine 7
ASTRONOMY
Yale Astronomers Take a Closer Look
at Star Birth
BY KAMARIA GREENFIELD
Earlier this year, Associate Professor Héctor Arce of Yale’s Astronomy
Department and his international collaborators were some of the first
to see two decades of collective scientific effort begin to bear fruit. Arce
and his team, which included Diego Mardones of the Universidad de
Chile and several others, studied the behavior of protostars and their
outflows using the Atacama Large Millimeter/sub-millimeter Array
(ALMA). Their discoveries about the dynamics of star formation were
only made possible by the new array. The conception of ALMA dates
back to before 2002, when the National Science Foundation (NSF) and
the European Southern Observatory (ESO) agreed to build an array
of unprecedented scale in Chile. Since then, the National Astronomical
Observatory of Japan (NAOJ) has also joined the coalition. This array
has been highly anticipated within the scientific community, with the
facility’s director comparing its inception to “opening a new window.”
ALMA, which detects radio waves instead of visible or infrared waves,
is ideal for studying dark parts of the universe where stars are in their
embryonic phase. Using the new technology, researchers were able to
obtain high-resolution images of the carbon monoxide gas streaming
away from a protostar. The particular region under scrutiny is located
in the constellation Vela, around 1,400 light years away.
The images led to two main developments in the understanding of
star formation: first, the ALMA images more clearly showed that star
growth occurs episodically (as opposed to constantly); second, the outflows
— ejected molecular material — have much more momentum
and kinetic energy than previously speculated. This particular outflow
and its collision with the surrounding atmosphere have been named
Herbig Haro 46/47. In general, Herbig Haro objects are small, volatile
regions closely associated with star formation. HH 46/47 stands out as
a significant discovery since its protostar is believed to typify protostars
of its kind and has a mass very similar to that of our own sun. There
are several ramifications of these discoveries. “We can assume that this
energy and momentum that we see will affect, for example, the timescale
that the star will take to form, [and] the amount of material that can be
around to form the star,” Arce said. “This implies that these outflows
have considerable impact on the ways that stars form.” The episodicity
of the growth, meanwhile, affects how the star’s gaseous building
IMAGE COURTESY OF ALMA/ESO
The antennas of the Atacama Large Millimeter/submillimeter
Array (ALMA) observatory stand out against the Chilean
night sky.
IMAGE COURTESY OF ALMA/ESO
The Herbig-Haro object HH 46/47, depicted with jets emerging
from a star-forming dark cloud.
blocks are gathered. “If we want to understand where we come from,
we need to understand how stars and solar systems form,” Arce added.
Since the images of HH 46/47 produced using ALMA were obtained
over a period of only five hours and by using only a quarter of the
full array, these findings represent only a small fraction of the new
technology’s capabilities. Based solely on the quantitative parameter of
collecting area — the array has 66 antennas ranging from 23 to 39 feet
in diameter — ALMA is at least ten times better than any of its predecessors.
Arce also noted a number of other advantages including its
improved technology and ideal placement. The array is located at over
three miles above sea level in northern Chile’s Atacama Desert — arid
conditions and high altitude.
The researchers have high hopes for future projects utilizing the new
technology. “You could do two things: you could do a more sensitive
project or observations with much higher resolution, or you could do
something similar in much less time,” Arce said. He anticipates that it
will also be possible to study numerous protostars at different points in
their evolution, creating a fuller picture of what was up until recently a
patch of the universe shrouded in mystery. Stuartt Corder, a researcher
at the ALMA Observatory and co-author of Arce’s recently published
paper on star formation, emphasized that ALMA is still in its infancy and
said that the technology is expected to provide “even better images than
this in a fraction of the time.” The team plans to expand their project
by eventually comparing their research with hydrodynamic models of
outflows and seeing how these outflows affect the surrounding gas cloud.
Arce, who came to Yale in 2008 and teaches a course called “Interstellar
Matter and Star Formation,” said that he has mentioned this part of
his research briefly to students before but plans to share this abundance
of new material with them. “I always try to incorporate my research in
my course,” he said. “Now that the results are out and the full analysis
is done, I can talk more about it.”
Already, other researchers have also used the revolutionary capabilities
of ALMA to further their own projects. In early September, it was
announced that a team had discovered a massive protostar developing
far closer to home in the Milky Way.
An Associated Foreign Press article from March states that all 66
antennas of ALMA should be fully operational by October.
8 Yale Scientific Magazine | November 2013 www.yalescientific.org
School of Medicine Professors Illuminate
the Language of the Brain
BY WILLIAM GE
Dr. Vincent Pieribone, Associate Professor of Neurobiology at Yale
School of Medicine, is currently submarine diving in the Solomon
Islands in search of shining proteins. If he finds them, it will mean
advancement for the entire field of neurology.
Understanding how
the brain works is
undeniably one of the
greatest challenges of
our time, and one that
dates back hundreds
of years. Although
scattered hypotheses
have long strained
for a coherent theory
of the brain, efforts
have been limited
by our ignorance
of the brain’s
labyrinthine circuitry.
“Traditionally, we
would rely on invasive
electrodes to sample
very limited areas of the brain, and only a few
neurons at a time,” Pieribone explained. A 2012
study at the University of California, Berkeley
characterized this level of imaging as akin to
viewing “an HDTV program by looking just
at one or a few pixels on a screen.” Imaging
technologies such as fMRI have improved our
historical myopia of the brain’s inner circuits, but
they are indirect methods which monitor areas
of high metabolism in the brain, as opposed to
actual neurons firing.
A collaboration between Dr. Vincent Pieribone and Dr. Michael
Nitabach of the Yale School of Medicine has produced a chimeric,
engineered molecule which has the power to illuminate the circuitry
of the brain. The molecule, dubbed ArcLight, has two functional
components. The first is a voltage sensor domain, a transmembrane
protein module containing positively charged amino acids. Voltage
changes across the membrane (in the case of neurons firing) cause a
change in the electric field in which these positive charges sit, and that
imposes a force on the positive charges and changes the conformation
of the domain. The second component, a mutated form of green
fluorescent protein (GFP), is fused to the voltage sensor domain. When
the sensor domain changes conformation, it also changes the shape
of the GFP, which affects the level of fluorescence. Thus, ArcLight
can be used to effectively map millions of neurons firing in real time
by the intensity of fluorescence each gives off.
The implications of this discovery are striking. “Behaviors and
biological processes can be associated with patterns of light,” explained
Pieribone. “For example, when people touch something, there is a
pattern associated with that action. We can ask: what does the brain
NEUROSCIENCE
do? Or, to add a twist, what happens if you lose your arms?” In their
study, Nitabach and Pieribone used ArcLight to demonstrate that
neurons involved in the circadian rhythm of a fruit fly were more
active in the morning than the evening. “This is something you could
only see this way,” said
Nitabach.
However, even this
new method of neural
imaging is not without
limitations. Current
efforts to improve the
protein probe include
increasing the intensity
of the fluorescent
signal in response
to smaller voltages
and increasing the
speed of response
(current lag time is
~20 milliseconds).
Moreover, the GFP
is limited to absorbing
blue light and emitting green light; if alternate
versions could be discovered that can absorb green
light (and thus emit red light), ArcLight could
be used in conjunction with other fluorescent
sensors (e.g. calcium detectors) which emit green
light to produce a system to investigate other
variables of brain activity. Finding these alternate
versions is one of the reasons why Pieribone is
diving in the deep Pacific. If the new proteins
are found, neural systems in which specific
processes can be excited by light (optogenetics)
Above: The mutant isolated from a fluorescent chordate, C. intestinalis (left), was
engineered into a molecule that can read a fruit fly’s (right) mind. Below: The lead
collaborators of the project, Vincent Pieribone (left) and Michael Nitabach (right).
IMAGES COURTESY OF YALE SCHOOL OF MEDICINE
IMAGES COURTESY OF ERIC GIBGUS/NUZRATH NUZREE
can be used concomitantly with ArcLight in order to selectively and
comprehensively decode the electrical circuits that lie at the heart of
neuroscience.
Last April, the Obama administration
unfurled a long-term scientific
effort to map the human
brain and its activity in the
Brain Research through
Advancing Innovative
Neurotechnologies
(BRAIN) Initiative. The
initiative is projected to
cost 300 million dollars
per year over a period
of the next ten years.
Here at Yale, in the
labs of Nitabach and
Pieribone, it looks like
it is already paying off.
IMAGE COURTESY OF
PROTEIN DATA BANK
A mutated form of the protein GFP
acts in ArcLight as the fluorescent
indicator of electrical activity.
www.yalescientific.org November 2013 | Yale Scientific Magazine 9
CHEMISTRY
Myocardial ischemia, or restriction of blood flow to the heart, can
cause serious and irreversible damage in cardiac tissue. Now, however,
an interdisciplinary team of researchers led by Yale Professor of
Medicine, Epidemiology, and Pathology Richard Bucala has developed
a group of small molecules that limit the damage that myocardial
ischemia causes. Bucala hopes to see these molecules developed into
drugs to limit ischemia’s detrimental effects.
Myocardial ischemia can have several causes. Heart attack victims
suffer from restricted blood flow, and surgeons sometimes intentionally
restrict blood flow to the heart during invasive surgeries like coronary
bypass. In either case, prolonged
ischemia can lead to cell death
and permanent damage of the
heart muscle, causing abnormal
rhythms and reducing the heart’s
ability to pump effectively. The
molecules designed and tested in
several studies by Bucala and his
colleagues could prevent some of
that damage.
Other members of the
research team include Yale
Sterling Professor of Chemistry
William Jorgenson and Yale
School of Medicine Professor
of Cardiology and Cellular and
Molecular Physiology Lawrence
Young. The team also includes
former Yale School of Medicine
faculty member Ji Li, an assistant
professor of pharmacology and
toxicology at SUNY Buffalo.
The molecules described in
the study target Macrophage
Migration Inhibitory Factor
(MIF), a cytokine cloned by
Bucala’s research group that
regulates inflammation pathways
found in macrophages, endothelial cells, T-cells, and cardiomyocytes. In
addition to being produced during immune responses, MIF production
is stimulated in the heart by lack of oxygen. Bucala and Young have
collaborated before to investigate the role of MIF in responding to
ischemic conditions. According to Bucala, Young “was very interested
to learn that we had mice in which we had genetically knocked out
the MIF gene. He was really interested in the role of AMPK [AMPactivated
protein kinase] in cardiac ischemia.” In his study, Young found
that mouse hearts missing the MIF gene were less able to overcome
ischemic injuries. MIF binds to the transmembrane receptor CD74,
which initiates a signaling pathway that leads to AMPK activation.
AMPK increases glucose uptake and limits apoptosis during ischemia,
thereby limiting damage to the heart.
Small Molecules Present Promising
Treatment For Ischemia
BY ZACHARY MANKOFF
IMAGE COURTESY OF THE PROTEIN DATA BANK
A rendering of Macrophage Migration Inhibitory Factor
(MIF), for which Bucala’s research group discovered small
molecule activators.
During the time he collaborated with Young, Bucala was also working
with Jorgensen to develop small molecule MIF inhibitors that could
be used to protect against autoimmune responses. As part of a study
originally published in Bioorganic and Medicinal Chemistry Letters in
December 2010, Jorgenson and his lab developed computer models of
several small molecules using the software BOMB (Biochemical and
Organic Model Builder), and synthesized the molecules in the lab. The
program, which was developed by Jorgenson, assists with designing
small molecules that fit with known structures of protein binding
pockets. When assaying the BOMB-designed molecules for MIF
inhibition, Bucala and Jorgensen
unexpectedly discovered that
some of the molecules increased
MIF activity. Bucala hypothesizes
that these small molecule agonists
induce conformational changes
that enhance binding between
MIF and its receptor.
More recently, Bucala’s team
assessed the potential for the
agonists’ therapeutic value by
assaying the molecules’ effects in
in vitro studies on cardiomyocytes
and ex vivo studies on mouse
hearts, as well as their effects on
living mice. Addition of MIF20,
the most potent of Jorgenson’s
small molecule activators, to
mouse cardiomyocytes in vitro
increased phosphorylation of
AMPK and other downstream
effectors. Furthermore, the
addition of MIF20 to an ex vivo
mouse heart before inducing
ischemic conditions allowed the
mouse heart to more fully regain
a normal heart rate after normal
conditions were restored. The
addition of MIF20 to the ex vivo heart also increased both glucose
oxidation and AMPK activity in postischemic conditions. Lastly, mice
treated with MIF20 and subjected to localized ischemia around the
heart showed less necrosis, or death, of heart tissue than mice not
treated with MIF20.
Bucala is also working with Yale’s Neurosurgery Department to
investigate the use of these molecules to treat traumatic brain injury.
According to Bucala, “We are looking for partners now to develop the
agonists.” The group is also hoping in the near future to investigate
the small molecules’ therapeutic potential using large mammal models.
If they are developed into drug therapies after human trials, the small
molecules would have wide applications for limiting complications due
to heart attacks or restriction of blood flow during surgery.
10 Yale Scientific Magazine | November 2013 www.yalescientific.org
A team consisting of Adam Marcus, Daniel Spielman, and Nikhil
Srivastava has solved the 1959 Kadison-Singer Problem. Originally
posited by Richard Kadison and Isadore Singer, the problem is an
important cornerstone in the mathematics underlying quantum
physics, relating to the measurements of quantum properties.
Professor of Computer Science,
Mathematics, and Applied
Mathematics Daniel Spielman
explained that the Kadison-
Singer Problem has a long
history intertwined with many
other problems. “Akemann and
Anderson proved that a positive
solution to the Kadison-Singer
Problem is equivalent to the
Paving Conjecture, which looks
like a conjecture in linear algebra,
you could say,” he explained.
Over the years, mathematicians
realized that this problem was
equivalent to many other difficult
and hitherto unsolved questions.
“I got into this problem a little
over 5 years ago with a graduate student, Nikhil Srivastava, and
an undergraduate, Josh Batson,” said Spielman. A comment from
visiting Professor Gil Kalai of Hebrew University sent Spielman in
the direction of the Kadison-Singer Problem, which looked fairly
similar to Spielman’s work at
the time. “We were wrong,” said
Spielman. “It was nothing like our
work at the time.”
Upon starting work on the
Kadison-Singer Problem,
Spielman and his team quickly
realized that the problem would
not be easily solved. Spielman
said he and his team only came
upon a good idea every six months
and only realized they were
wrong about their previous idea
once a year. However, Spielman
maintained that his team made
good progress on the problem.
“An interesting thing worth
mentioning is that the math we
were using in this problem is
actually very simple ... that is,
MATHEMATICS
Yale Mathematicians Solve 54-Year-Old
Kadison-Singer Problem
BY AMEYA MAHAJAN
you could understand it after earning an undergraduate degree in
mathematics,” said Spielman. The comparatively easy mathematics
used in this case relates to special polynomials that have all real roots.
In particular, they consider polynomials whose roots interlace. That
is, the smallest root of the first is smaller than the smallest root of
the second, which is in turn smaller than the second root of the first
— and so on. Also crucial to Spielman’s work were computational
experiments. “We ran a lot of computer experiments ... they work
as something of a sanity check,” said Spielman. He and his team
designed computer programs that
prove mathematical inequalities
autonomously, preventing many
missteps that could have extended
the work time for this problem even
further.
After years of work, Spielman and
his team were finally able to confirm
that the extensions referenced in
IMAGE COURTESY OF SOUL PHYSICS
The spin of an electron, which can be “up” or “down,”
is known as an “observable.” Compatible observables
can be measured at the same time, while incompatible
observables cannot be. According to the Kadison-Singer
Problem, a basic probability distribution from a set of
compatible values allows us to extend this distribution to
all other observable values, including incompatible values.
Professor Daniel Spielman and his colleagues have solved
a mathematical problem that lies at the cornerstone of
quantum physics.
the Kadison-Singer Problem are in
fact unique, allowing the problem
to be used in order to create specific
definitions of quantities in quantum
physics.
The Kadison-Singer Problem
has important consequences for
the defining of quantum states. In
quantum physics, some quantities,
also called states, are definable and measurable, while others are
probabilistic and can only be mathematically postulated. The positive
solution of the Kadison-Singer Problem allows physicists to extend
their knowledge about simultaneously measurable quantities and
extend this to other potentially
measurable quantities. Spielman also
said the conjecture has connections
to theoretical computer science, his
own field. “If I have a social network,
with any number of people, that
network has edges [or connections]
between each person. Our work
with this conjecture lets us shave off
many, many edges from that situation
and still have a clear picture of
what’s going on,” he said. Spielman
explained that these connections
to fields other than mathematics
were a driving force behind his
decision to continue working on this
problematic question.
Spielman and his team have
another couple of papers planned in
their current series of publications.
He and his team would like to use interlacing polynomials to create
some very simple proofs of complicated mathematical ideas. “We’d
like to get rid of some ambiguity,” said Spielman. “For example, we
like to say ‘a finite number’ — well, I’d like us to say ‘2’ instead.”
IMAGE COURTESY OF THE MACARTHUR FOUNDATION
www.yalescientific.org November 2013 | Yale Scientific Magazine 11
THE FUTURE OF
SPACE EXPLORATION
delving into the final frontier
NOTE TO LATER EDITORS/LAYOUT - THE TEXT OF THIS ARTICLE
HAS BEEN UPDATED IN THIS LAYOUT VERSION. DON’T REFER TO
THE DRAFT IN THE SERVER FOLDER (WORDING CHANGES, AND
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by ariel ekblaw
“
easy
because they are , because that goal will serve to organize and measure the of our
WE CHOOSE TO GO TO THE MOON.
We choose to go to the moon in this decade and do the other things, not because they are
hard
In the 51 years since John F. Kennedy’s
Rice Stadium Moon Address, space
exploration has captured the imagination
of several generations in the U.S. and abroad.
His vision articulated goals much grander than
the moon landing, especially his intention
that as the “exploration of
space will go ahead … we
mean to lead it.” Have we
fulfilled his mandate?
We now face a changing
landscape for space
exploration, as industry and
commercialization, rather
than government efforts,
claim a growing share of
aerospace development in
the U.S. Pressure from the
burgeoning Chinese space
development program and
our recent reliance on the Russian Soyuz
spacecraft to reach the International Space
Station (ISS) have forced us to acknowledge
a globalizing trend in space exploration. With
exquisite advances in robotics and remote
data sensing, the glorious manned space
missions of the Apollo
era now share the limelight
with distant probes and
unmanned rovers. Through
several rounds of tough
budget cycles and trying
tragedies, we have at times
postponed the challenge
posed to us by President
Kennedy, though the
allure of space exploration
reliably recaptures our
attention, sparking further
discovery and innovation.
”
John F. Kennedy
September 12, 1962
NASA’s Evolving Role
Our modern conception of space
exploration was born during the Cold War.
The successful Soviet launch of Sputnik, the
world’s first artificial satellite, on October 4,
1957 spurred the U.S. government to create
NASA (National Aeronautics and Space
Administration) and place space exploration
high on the national security priority for
over three decades of fervent technological
competition.
Now, NASA shares the opportunity for
exploration with circles beyond their core of
career experts. Through their Microgravity
University, the space exploration behemoth
pulls in young talent, giving teams of budding
aeronautical engineers, astronauts, and space
scientists the opportunity to solve NASA’s
current design challenges. Frank Prochaska,
energies and skills, because that challenge is one that we are willing to accept, one we are
unwilling to postpone, and one which we intend to
IMAGE COURTESY OF THE NASA HISTORY OFFICE
John F. Kennedy delivers his
address, declaring intentions to
send an American to the moon
by the end of the decade.
win.
BEST
12 Yale Scientific Magazine | November 2013 www.yalescientific.org
, but
AERONAUTICS
Manager of the Reduced Gravity Education
Flight Program (RGEFP), creates these
opportunities for the students to “use their
creativity to solve technical problems currently
facing NASA engineers and scientists.”
After months of technological
development in collaboration with a stringent
NASA oversight committee, the students
fly their experiments in a modified Boeing
727 “Zero-G” aircraft over 30 demanding
parabolas of microgravity, normal gravity,
and hypergravity. Prochaska heralds these
youth-centered efforts as the future of space
exploration. As NASA updates its mission for
the 21st century, we can expect new creativity
www.yalescientific.org
IMAGE COURTESY OF NASA
Top: Zero-G Parabolic Flight. Bottom:
Members of the Yale Drop Team
contribute to the next generation of
space science as they study the Raleigh
Taylor Instability in Changing Gravities
as part of the Reduced Gravity Education
Flight Program.
in their programs, such as the RGEFP, and
a revitalized reverence for man’s desire to
explore.
Throughout NASA’s projects,
collaborations between government
technology and academic research labs stand
poised to produce key discoveries in space
science. Yale Professor of Astronomy Priya
Natarajan looks forward to a promising
future for space exploration, most recently
exemplified in the breathtaking achievement
of NASA’s 1977 Voyager probe as it exited the
Solar System. Natarajan hopes that the probe,
after years of loyal service to the scientific
community, will offer captivating new insights
for astrophysics. Reminding us of the scale
of this achievement, and more to come, she
noted that not since the intrepid explorers of
the 1500s has a product of the human race
crossed such a momentous frontier. For her
research on the fundamental nature of gravity
and dark matter, Natarajan anticipates fruitful
future projects with the next generation
of space probes such as LISA, the Laser
Interferometer Space Antenna. Though
NASA has had to step away from LISA due
to funding challenges, the European Space
Agency will take on the mantle of advanced
gravity research in their plans for the New
Gravitational-wave Observatory.
These symbiotic relationships between
NASA technologies and academic research
promise an exciting future — but is this
promise enough? Can the government
muster the economic capital and efficiency
to get man back to the moon? Enter a new
figure in this longstanding relationship: the
space exploration industry. Though private
industry contractors have long played a part
in the development of space technology
(notably Boeing’s long history in aerospace
engineering), the last ten years have witnessed
an explosion of new private space ventures
and companies. From cutting-edge rocket
development to commercial luxury space
flight, each corporation has found its niche
in the market. Now attracting top talent,
these profit-centered industries are taking a
competitive, time-pressured and dramatically
efficient approach to space exploration.
The Rise of the Space Industry
In less than a decade of existence, Space
Exploration Technologies (SpaceX) delivered
a cargo payload to the International Space
Station via their Dragon Spacecraft. As
the first commercial spacecraft ever to
dock with the ISS, the Dragon represents
a successful collaboration with NASA
through the Commercial Crew and Cargo
Program. Through further innovation, the
young company’s recent advances in reusable
rocketry with the Falcon 9 rig will shape a new
paradigm for future launches. In 2012, NASA
announced agreements with three American
space industry companies “to design and
develop the next generation of U.S. human
spaceflight capabilities, enabling a launch
of astronauts from U.S. soil in the next five
years.” Working under the Commercial Crew
Integrated Capability initiative, Sierra Nevada
Corporation, SpaceX and Boeing were
collectively awarded over $1 billion to develop
this new technology. These companies
are revolutionizing space exploration at a
blistering pace and inspiring a new generation
of aerospace engineers, scientists, and space
enthusiasts among the public.
Fundamental to the recent birth of the
space industry, incentivized competitions run
by the X PRIZE Foundation have mobilized
public interest and profoundly advanced
the state of our society’s space exploration
ventures. As stated in their mission, X
IMAGE COURTESY OF SPACEX
The reusable “Grasshopper” rocket
system, developed by SpaceX, flew to a
250 m height with 100 m lateral maneuver
and then regained its initial position
on the launch pad. Grasshopper is the
name fondly given to the over 10-story
Falcon 9 test rig.
PRIZE competitions “bring about radical
breakthroughs for the benefits of humanity,
thereby inspiring the formation of new
industries and the revitalization of markets.”
Most influential for space exploration, the
$10 million Ansari Prize was awarded to Burt
Rutan’s SpaceShipOne team in 2004, after
they succeeded in achieving private suborbital
flight two times within two weeks. The Ansari
X Prize is often hailed as an impetus for
innovation in space exploration.
A more recent exploration competition
began in 2007, the Google Lunar XPRIZE
headed by Alexandra Hall. In order to win
the $20 million prize, by December 31, 2015
a private company “must land safely on the
surface of the Moon, travel 500 meters above,
below, or on the Lunar surface, and send
back two ‘Mooncasts’ to Earth.” One of
the companies engaged in the competition,
Astrobotic Technology, has already secured
a contract with SpaceX for a launch on the
Falcon 9 in October 2015.
Director Alexandra Hall predicted that
“the future of space exploration will be
one marked by partnerships of all kinds
and involving disciplines that have not
necessarily been involved with space until
now.” Compelling economic arguments can
be made for investment in space technology,
as the success of commercial entities “will
lead to businesses, job growth, and wealth
in sectors from biology, to materials science,
November 2013 | Yale Scientific Magazine 13
AERONAUTICS
space exploration through the years
a TIMELINE of MAJOR
ACHIEVEMENTS
1972: apollo 16 moon landing
IMAGES COURTESY OF NASA
1984: space shuttle discovery’s maiden launch
2000: international space station first occupied
to mining and resource utilization.” Google’s
Lunar XPRIZE aims to breach the frontier
beyond Earth’s orbit repeatedly and at low
cost. To achieve this, Hall prioritizes further
developments in lunar orbit communications
and navigation networks, the establishment
of refueling depots at strategic points in
space, and the expansion of communications
networks on earth that receive signals from
space. Commenting on the impact of the
rise of space exploration industry, Hall noted
that “moving the R&D from just being
governments, to including the commercial
sector means that everything from the
amount of risk that we’re willing to take, to
the legal and regulatory infrastructures will be
challenged. All for the good.”
Creativity in the Pursuit of Space
Inventive approaches to space exploration
hardly end with the X PRIZE Foundation.
Planetary Resources, a company dedicated to
asteroid mining, has stated that “harnessing
valuable minerals from a practically infinite
source will provide stability on Earth, increase
humanity’s prosperity, and help establish and
maintain human presence in space.” With
influential industry backers (Google’s Larry
Page, Virgin Galactic’s Richard Branson,
X PRIZE’s Peter Diamandis, and James
Cameron among others) and an expert team
of technical talent, Planetary Resources is
surprisingly well-placed to tackle what would
have been an outlandish sci-fi mission just a
few years earlier.
Building up to their asteroid ambitions, they
recently completed their successful ARKYD
Kickstarter campaign, raising over $1.5 million
in the first crowdsourced funding venture
to offer public access to an advanced space
telescope. Space exploration crowdsourcing
is taking off in its own right as the CubeSat
Project, “an international collaboration of
over 40 universities, high schools, and private
firms developing picosatellites containing
scientific, private, and government payloads”
gives everyday individuals the chance to send
small-scale modular projects into space. With
a crowdsourced funding model, the cost is
shared among all the participating members
of a particular cube’s launch.
The Pressure and Promise of Globalization
Complicating this dynamic network of
governmental, academic, industrial, and
now crowdsourced interests within the U.S.,
several other nations have taken steps to
pursue space exploration. China’s proposals
for a new International Space Station by
2020 and a Chinese moon colony soon
thereafter force us to grapple with the
political implications of space technology.
Hall stated, “as space exploration matures,
I believe we will increasingly see the role
of governments and consortia of nations
in building out infrastructure at each new
frontier.” Prochaska concurred, noting
that space exploration is a “phenomenally
complicated puzzle and we’re working
internationally with other Government space
agencies” to put the pieces together.
These multinational efforts stand to
incentivize competition, galvanize space
exploration, and advance humanity’s prospects
for the future. As we look to the final frontier,
a diverse fellowship between corporate and
government interests, small-scale and largescale
projects, and research will take us there.
The future of space exploration is bright, and
now, more accessible than ever.
2009: butterfly nebula from hubble space telescope
About the Author
Ariel Ekblaw is a senior Physics and Math-Philosophy double major in Pierson
College. Currently working with Yale Professor Eric Dufresne on a biophysics soft
matter project, she flew in zero gravity with the Yale Drop Team in 2012. She hopes
to pursue a career in bioengineering for space or astrobiology.
Acknowledgements
The author would like to thank Frank Prochaska, Priya Natarajan, and Alexandra Hall
for their time and thoughtful contributions to the article.
2012: curiosity rover lands on mars
Further Reading
• NASA, “Reduced Gravity Education Flight Program: Microgravity University.” Last
modified 2013. http://microgravityuniversity.jsc.nasa.gov/
14 Yale Scientific Magazine | November 2013 www.yalescientific.org
TB
UNDERSTANDING
THE
AND ITS LINK TO
EPIDEMIC:
BY EMMA GRAHAM
HIV
There are few diseases that match
the persistence and pervasiveness
of tuberculosis (TB). Mycobacterium
tuberculosis, the bacterium that causes the
infection, resides in the bodies of one-third
of the human population. Most infections
are latent, meaning that they do not produce
any symptoms. In latent TB, the bacteria lie
dormant in the lungs, secluded from the rest
of the body and suppressed by immune cells
called macrophages. Latent TB, however, can
suddenly become active, causing symptoms
that include coughing, fatigue, and loss of
appetite. In healthy patients, dormant bacteria
have only a 10 percent chance of becoming
active. In immunocompromised patients,
however, the chance of reactivation is greatly
increased. Indeed, throughout the past ten
years, the number of patients infected with
both HIV and TB has increased dramatically.
Tuberculosis and HIV
Geographically, TB is prevalent
throughout Asia, Eastern Europe, Russia,
and Sub-Saharan Africa. With 24 percent of
the world’s TB cases, Africa has the highest
per capita mortality from the disease. The
region also happens to be the epicenter of
www.yalescientific.org
the HIV epidemic. HIV destroys the ability
of the human host’s macrophages to control
TB infection, a fact that explains the high
lethality of the disease in patients with both
TB and HIV compared to TB in otherwise
healthy individuals. This fact has exacerbated
the global TB epidemic, especially in regions
of the world where TB and HIV are most
prevalent.
Why Sub-Saharan Africa?
While the despairingly high prevalence of
TB and HIV in Sub-Saharan Africa could
once have been attributed to the lack of
public health initiatives and infrastructure in
the region, researchers have now pinpointed
a more basic reason for the disease’s
ethnocentricity (meaning its high incidence
among specific populations). Our genetic
makeup has long been known to play a
role in our susceptibility to tuberculosis
and its progression. Researchers including
Dr. Richard Bucala, a professor at the Yale
School of Medicine, are examining the
genomes of different human populations
in an attempt to identify small differences
that might make certain populations more
susceptible to diseases such as tuberculosis.
Specifically, Bucala’s research investigates
how genes can influence the body’s response
to different pathogens. Bucala’s lab recently
discovered a functional polymorphism in a
gene that strongly influences our response
to TB. This gene is called macrophage
migration inhibitory factor (MIF), and the
immune protein it encodes is produced by
agents of the immune system (macrophages,
leukocytes, and pulmonary epithelial cells)
upon infection. The MIF gene has a common
polymorphism in its promoter region that
results in two main variants: a low-expressing
variant and a high-expressing variant.
The difference between these variants,
or alleles, lies in the different number of
short DNA repeats in the promoter. The
low-expressing variant has five repeats of
a tetranucleotide regulatory sequence while
the higher-expressing variants have more
than five repeats, leading to correspondingly
greater expression. After discovering this
polymorphism, Bucala started measuring
the distribution of these variants in human
populations within the United States.
In nursing home studies carried out
previously by other researchers, African-
American patients had been shown to
be more susceptible to developing more
November 2013 | Yale Scientific Magazine 15
MEDICINE
lethal tuberculosis than Caucasian patients.
Interestingly, Bucala found that while the
low-expressing variant is expressed by 65
percent of African Americans, it is only
expressed by 45 percent of Caucasians.
Noticing this trend, Bucala then sequenced
the MIF gene in different populations from
around the world. The low-expressing variant
was most prevalent in Sub-Saharan Africa,
with 78 percent of Zambians, for instance,
possessing the low-expressing variant.
ESTIMATED TB INCIDENCE RATES, 2010
MIF and Malaria
The prominence of the low-expressing
MIF variant was not the only genetic
discovery within the Zambian population.
Unlike their counterparts in Northern
African and Mediterranean countries,
populations in Southern Africa were known
to lack the sickle cell gene, a variant in the
hemoglobin gene that confers malarial
immunity in heterozygous individuals at
the cost of anemia and shortened lifespan
in homozygous individuals. Realizing this,
Bucala hypothesized that the low-expressing
MIF gene helps provide immunity against
malaria, as it suppressed the excessive
inflammatory response that often kills
malaria-infected children. The group studied
African children with malaria and found
that a low-expression MIF allele was indeed
associated with less severe disease.
Mouse models of malaria or TB infection
performed by Bucala confirmed that having
IMAGE COURTESY OF RICHARD BUCALA
The areas with the highest TB incidence rates correspond to populations with
predominantly low-expression MIF alleles, suggesting that having the low-expression
allele makes you more susceptible to TB infection.
a low-expression variant of the MIF gene
correlates with both less severe malaria
but higher likelihood of developing TB
pathology. Accordingly, it was predicted that
TB patients with low MIF would be more
susceptible and less able to fight off TB
infection. Rita Das, a graduate student and
infectious disease fellow in the Bucala lab,
found evidence for this in humans as HIVpositive
Ugandan patients with disseminated
(widespread) TB were 2.4 times more likely
to have a low-expressing variant of the MIF
gene than those without bacteremia.
The low-expressing form of MIF is a
double-edged sword. The low-expression
variant, by preventing a full immune
response, protects people from the lethal
inflammatory complications of malaria. Yet
at the same time the variant can increase
susceptibility to TB and act as a marker for
poor prognosis of disease progression.
Population Stratification of the MIF locus
Low-expressing MIF alleles occur
disproportionally in Africa. Bucala
postulates that this stratification of the MIF
locus occurred when a small population of
individuals migrated out of Africa about
100,000 years ago. As this population
reached colder climates with less malaria and
encountered new, life-threatening pathogens,
the benefit of the low-expressing allele was
lost in favor of the higher-expressing allele.
IMAGE COURTESY OF RICHARD BUCALA
While HIV is prevalent throughout the world, the epidemic is at its highest incidence
rates in Southern Africa. In this region, it is estimated that 50 percent of new TB
patients are also infected with HIV.
You Take the High Road and I’ll Take the Low
Road
While the prevalence of the low-expressing
form of the MIF gene in Sub-Saharan Africa
can be explained by the immunity it confers
to lethal malaria, its prevalence in areas
such as North America and Europe cannot
be explained as easily. Common diseases in
these regions include community-acquired
pneumonia, a disease that can lead to sepsis
(a state of overwhelming infection) and
death if not treated. Community-acquired
16 Yale Scientific Magazine | November 2013 www.yalescientific.org
MEDICINE
TY
hogen
55/GG
56/GG
56/GC
66/GG
66/GC
bia
ambia
sor
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e
t
e
ine the
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ons.
re
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overy
ning
has
sor
yses of
ttings.
57/GC
VISUAL APPEARANCE OF INDIVIDUAL BIOCHIPS, which measure only 1 square cm, showing every possible
above combination left: of MIF Rapid allele (5, determination 6, 7, and 8 repeat) together of MIF with a allele related in single areas nucleotide without polymorphisms genomic (G or analysis C) technology is now available with biochips,
Pictured here are biochips showing every combination of MIF allele (5, 6, 7 or 8 short DNA repeats) and a single nucleotide
individuals who have more repeats produce more enables direct visualisation of a patient’s MIF
polymorphism. above right: Dr. Richard Bucala (left) and Dr. Rita Das (right) in front of the Botswana Ministry of Health.
MIF. “Depending on the individual,” continues genotype without the need for sophisticated
Bucala, “this repeat can be present in five to eight instrumentation. “All too often,” says Bucala,
pneumonia is the leading cause of noncardiac
First, inexpensive techniques are needed to this global epidemic.” Bucala is currently
copies; the more copies that are present, the more “exciting discoveries or technologies are
the gene
intensive
that is expressed
care unit
and
deaths
the greater
in the
the
U.S.,
developed
determine
that
each
are not
individual’s
economically
MIF
practical
variant. working with Dr. William Jorgensen in the
simply inflammatory because response of how during easily an infection.” sepsis can By be for widespread To this application. end, Witness rapid the and problem affordable Yale Department of Chemistry on ways to
triggered. extending this The DNA-sequencing low expressing analysis MIF to allele a few has in providing diagnostic adequate methods care for have patients been infected developed increase MIF action in low MIF-expressing
been hundred shown individuals, to not the team only found exacerbate that people TB in with using HIV or biochips, tuberculosis.” small silicon chips with individuals. Supplementing MIF would
African of African-American populations, ancestry but to are lead more to likely reduced to The oligonucleotides benefits of being able attached to genotype to patients the surface provide an important adjunct to the current
survival have a low rates number from of sepsis repeats in in Americans their MIF gene with at the that bedside light are up clear: when as bound well as the to a cost specific method of combating resistant TB strains,
and as a result, to produce less MIF protein during
community-acquired pneumonia. In these being sequence. very low, the Using methodology this technology is robust, to the detect which involves taking multiple antibiotics for
an immune response. This work led directly to the
cases, the high-expressing allele is clearly needs which for training patients and are laboratory more facilities susceptible are
hypothesis that these low-expression variants
to many months, a difficult and costly treatment
minimised, and patients can be quickly identified
beneficial. of the MIF gene, or alleles, offer a selective malaria or TB infection will allow doctors to and one being circumvented by the everincreasing
drug-resistance of TB strains.
and ‘stratified’ according to their susceptibility
advantage Bucala’s to people clinical living expertise in Africa and there is in to lethal spend disease. more This time enables with quicker their cases, referrals whether
rheumatology exposed chronic and infections, autoimmune the most prevalent diseases. to that hospitals involves for monitoring longer hospitalizations, and aggressive more The discovery of geographic and
These and lethal diseases being malaria. are caused by excess treatments, antibiotic such use, as or blood an individually transfusions optimized and ethnocentric polymorphisms in the MIF
inflammation, Bucala notes that highlighting the human population an important has antibiotics, treatment which plan. saves lives and conserves gene led to a new understanding of the HIV/
context co-existed for with favoritism malaria for of the longest low-expressing period precious According medical resources. to Bucala, “we are slowly TB epidemic. No longer is geography simply
allele of time in Africa, North suggesting America. that Studies low-expression showed LOOKING developing TO THE new FUTURE antibiotics for TB, but an additional fact about the epidemic; it now
MIF alleles were favoured and selected for
that the low-expressing form of MIF is Given we the desperately central role need of MIF new in the tools immune to combat offers a unique explanation of its cause.
in order to allow individuals to escape the
associated with less severe rheumatoid response to malaria, the rapid genotyping of MIF,
lethal inflammatory consequences of malaria
arthritis, infection. “We systemic modelled lupus this idea erythematous, in a controlled and or other genetic polymorphisms of interest may
prove useful in field studies of malaria vaccines to
other laboratory inflammatory infection and disorders. found that geneticallyengineered
arisen mice to combat lacking the different MIF gene infections show
Genes that
different antigens. Such genetic information
have About may the Author
help to predict vaccine responsiveness in different
also enhanced have survival the ability during to lethal worsen malaria,” autoimmune Bucala
populations, Emma as Graham candidate vaccines is a sophomore progress in Trumbull College majoring in Molecular
inflammation, explains. His team emphasizing since verified the this balancing idea
through
by completing a genetic epidemiology study Biophysics clinical trials. and “Although Biochemistry. we developed
act that our immune system plays to keep us this biochip methodology specifically to allow for
in a malaria-susceptible population in Africa,
healthy.
the genotyping of MIF variant alleles,” continues
observing a significant protective effect of lowexpression
MIF alleles in the development of
Bucala, “it Acknowledgements
is broadly applicable to any genetic
polymorphism
Individualized severe malarial Treatment
The author of interest, would and like there to is thank ongoing Professor Richard Bucala for taking the time to share
anaemia.
work to his adapt research. this technique for the study of
RAPID GENOTYPING
other genes, both for malaria and other prevalent
Knowing what variant of the MIF
Genotype determination normally requires costly infectious diseases such as leishmaniasis.”
gene a person has can lead to a greater
and sophisticated analytical instrumentation Low-expression
Further
MIF
Reading
alleles are associated in
understanding that is available in of only that a few person’s specialised disease, centres and Western • populations Das R, Koo with M-S, protection Kim B-H, against Jacob ST, Subbian S, Yao J, Leng L, Levy R, Murchison
inflammatory C, Burman diseases WJ, Moore such C, as Scheld WM, David JR, Kaplan G, MacMicking JD,
how in Africa. best Ordinarily, to treat samples it. Those would suffering have to be from autoimmune
TB collected, and having shipped to a low-expression a laboratory for processing, MIF allele arthritis, asthma, Bucala and R. 2013. inflammatory MIF is a Critical bowel Mediator of the Innate Immune Response to M.
theoretically analysed by a genetic could analyser, receive and supplemental
the results disease. Investigation tuberculosis. of a polymorphic Proc Natl Acad genetic Sci USA 110;2997-3006.
MIF then reported to reset back their to the immune healthcare response providers. to locus that appears to have evolved in response
This is a process that normally takes many to lethal malaria infection therefore also
combat TB more effectively. However, as is • Bucala R. 2013. MIF, MIF Alleles, and Prospects for Therapeutic Intervention in
days to weeks, even in developed countries. provides one explanation for susceptibility to
the case with many infectious diseases, the
But Bucala’s team has developed a facile and the development
Autoimmunity.
of autoimmune
J Clin Immunol.
disorders
33;S72-S78.
epicenter inexpensive of ‘biochip’ the HIV/TB that, within dual two epidemic hours, is prevalent in many Western countries.
in a part of the world where analysis of each
person’s genome may not be cost-effective.
www.yalescientific.org
67/GC
67/CC
77/CC
78/CC
IMAGES COURTESY OF RICHARD BUCALA
November 2013 | Yale Scientific Magazine 17
TARGETING
Diabetes Diabetes
at its
Source
preserving insulin production in type 1 diabetes
Source
By Grace Cao
For many, a diagnosis of diabetes
carries with it a lifelong sentence
of glucose monitors and insulin
injections. Although associated technology
has improved, the essential nature of
treatment has not changed since the discovery
and subsequent commercial production
of insulin in the 1920s. However, a recent
clinical study led by Dr. Kevan Herold, Yale
Professor of Immunobiology and Medicine
(Endocrinology), aims to improve treatments
for patients with type 1 diabetes.
Most people are familiar with type 2
diabetes, a disease associated with poor diet
and excess weight; however, type 1 diabetes
is a more severe form of the illness, which
is most often diagnosed in children and
represents up to ten percent of all diabetes
cases. In this condition, immune cells
known as T cells attack insulin-producing
beta cells in the pancreas, which leads to
decreased levels of insulin production.
While a concrete cause for type 1 diabetes is
unclear, there is evidence for strong genetic
and environmental factors. As the disease
progresses and the death of beta cells results
in falling insulin levels, patients need to
deliver the insulin their body cannot supply
through injection or insulin pumps.
Though researchers and clinicians have
expanded their knowledge of the disease in
recent decades, options for treatment are still
limited. Diagnosed individuals must carefully
and constantly monitor their blood glucose
levels, then administer insulin at several
points throughout the day. Furthermore,
as Herold explained, since the advent of
insulin, “there has never been another
treatment that fundamentally changed the
natural history of the disease.” Even with
appropriate management, a significant
fraction of type 1 diabetes patients today
develop complications that include kidney
failure, blindness, and various neuropathies.
A Potential Treatment
Herold’s study may foreshadow a new
treatment that could change how patients
IMAGE COURTESY OF UCSF DIABETES TEACHING CENTER
In Type 1 diabetes, insulin production is
insufficient, decreasing glucose uptake.
manage their condition. In this clinical
trial, patients were treated with the drug
Teplizumab, a monoclonal antibody which
binds to a specific region of the CD3 receptor.
This receptor is found on the surface of
all T cells, including the ones responsible
for beta cell destruction in type 1 diabetes,
and helps T cells recognize their target
antigen. The reason that binding to the CD3
receptor reduces attacks on beta cells is as
of yet unknown. Unlike other CD3-targeted
antibodies, Teplimuzab does not simply
deplete T cells from the body. Research
by Herold and Richard Flavell, Sterling
Professor and Chair of Immunobiology at
Yale, suggests that the drug “causes cells to
migrate to the gut, where they may acquire
a regulatory function,” said Herold. These
induced regulatory T cells can then suppress
the immune response.
In the study, two groups of patients, all
of whom were within eight weeks of their
initial diagnosis, were treated, either with
Teplimuzab or with nothing as a control.
One year later, the patients were again treated
for two weeks with the same substance.
Throughout these years, the patients’
insulin production and consequently beta
cell function were monitored by measuring
levels of C-peptide, a short protein found in
a precursor to insulin.
What the researchers found was extremely
promising. In patients receiving the drug, the
18 Yale Scientific Magazine | November 2013 www.yalescientific.org
average decline in C-peptide was 75 percent
less than the control group after two
years, meaning there was
a 75 percent improvement
in insulin production.
However, not all the treated
patients responded similarly,
leading to a second critical
question: Why did some
patients respond better than
others?
Identifying Responders
To understand the
answer to this question, it
is important to first define responders and
non-responders. According to Herold, the
distinction is straightforward: “We looked
at the decline in C-peptide in the control
group after two years. Drug-treated subjects
who had the same level of decline are nonresponders,
and those with less decline
are responders.” Based on this criteria, of
the 49 treated subjects who completed the
study, 27 were non-responders and 22 were
responders. Examining the C-peptide levels
over time within these groups revealed
that non-responders actually had similar
levels of C-peptide as the control group. In
patients who responded to the treatment,
C-peptide levels remained at or above the
initial baseline for an average of 18 months,
and the level of C-peptide was almost three
times higher than the control group at this
time.
After discovering this drastic difference,
the team was very interested in determining
what caused it. “We thought for sure that
there were going to be big immunologic
differences, but [the distinctions] were fairly
subtle,” Herold said. Rather, “the major
difference seemed to be that the responders
used less insulin going into the trial than
IMAGE COURTESY OF HEALTH MEDIA
Patients with Type 1
diabetes require multiple
doses of insulin daily.
the non-responders, and also had better
glucose control.” While this initially seemed
counterintuitive, as one might
expect that responders would
end up with lower blood
glucose levels rather than the
other way around, the team
found the same trend when
they reevaluated previous trials.
One potential explanation is
that glucose levels may affect
immune responses or beta
cells directly. Herold’s lab is
interested in investigating
the links, as he believes
that “there’s an interesting
interrelationship between metabolic control
and immunologic effects that really has not
been addressed at all.”
Hope for the Future
The success of the trial has not stopped
Herold from looking toward improvements
and future applications. He is continuing to
track the response of patients in the trial to
see how long their C-peptide levels remain
stable. He has also continued to investigate
basic immunological questions about type 1
diabetes and Teplimuzab, including defining
biomarkers for the disease and investigating
the role of the microbiota in regulating
the differentiation of regulatory T cells
in the digestive tract. By improving our
understanding of the disease pathology and
interaction with the drug, more effective
interventions can be developed.
About the Author
MEDICINE
IMAGE COURTESY OF YALE IMMUNOBIOLOGY
Kevan Herold, Professor of Immunobiology.
In addition to these studies, Herold
is enrolling patients for an even more
ambitious trial, one which aims to prevent
or delay the onset of type 1 diabetes. “We
know from monitoring relatives of people
with type 1 diabetes that those who have
autoantibodies and altered glucose monitor
tests have a greater than 75 percent risk
of getting diabetes in five to seven years,”
he said. “The question is, if you come in
much earlier, does the drug prevent the
disease altogether?” If the trial shows that
Teplimuzab has an effect in preventing
type 1 diabetes, it could lead to a major
advance in patient care, as those at risk for
can currently do little to stop disease onset.
Together with Herold’s other ongoing
research, the study represents a longawaited
hope for improved type 1 diabetes
treatments.
Grace Cao is a sophomore Molecular, Cellular and Development Biology major in
Timothy Dwight College. She is a Yale Scientific copy editor and works in Professor
Carla Rothlin’s lab in the Immunobiology Department.
Acknowledgements
The author would like to thank Professor Herold for his time and enthusiasm in explaining
his research on type 1 diabetes.
Further Reading
• Daifotis, Anastasia G, Scott Koenig, Lucienne Chatenoud, and Kevan C Herold.
2013. “Anti-CD3 Clinical Trials in Type 1 Diabetes Mellitus.” Clinical Immunology.
IMAGE COURTESY OF BIOTUESDAYS
An insulin pump delivers insulin without
requiring multiple injections.
• Daneman, Denis. 2006. “Type 1 Diabetes.” Lancet 367 (9513) (March 11): 847–58.
doi:10.1016/S0140-6736(06)68341-4.
www.yalescientific.org November 2013 | Yale Scientific Magazine 19
uncovering
the
architecture
of our
synapses
20 Yale Scientific Magazine | November 2013
www.yalescientific.org
BY SOMIN LEE
Imagine a production of all 38 of Shakespeare’s plays,
performed back-to-back, complete with over one
thousand characters and nearly a million words. The
success of the production depends critically on each
character saying the exact right words at the exact right
times. Although the flawless execution of such a play seems
daunting, the human brain orchestrates a similar task in the
formation of 100 trillion synapses between over 100 billion
neurons during development.
Synapses are the connections neurons use to communicate
with one another, and the proper creation and maintenance
of these connections are necessary for normal brain
function. Exactly how the brain manages such complexity
has been an interest of Professor Daniel Colón-Ramos of
the Yale School of Medicine for nearly a decade. As we
grow, our brains increase nearly fourfold in volume. The
mechanism behind the maintenance of synapses during such
dramatic growth is one of his lab’s primary interests. Current
research in his lab has now uncovered that the regulation
of a cell type called glia during growth may hold the key to
synapse regulation.
C. elegans as a Model Organism
Due to the overwhelming complexity of working with the
human brain, Colón-Ramos studies synaptic connections
in Caenorhabditis elegans (C. elegans), a small roundworm
about one millimeter in size. C. elegans is well-suited for
neurodevelopmental research in several ways. One major
advantage of C. elegans is the ease of genetic manipulation in
the species. Scientists in recent decades have also constructed
the entire C. elegans connectome, which means that we now
know the identity, morphology, and connectivity of each
of the 302 individual neurons in C. elegans. Colón-Ramos
described working with an organism with a completed
connectome as “a bit like having an answer key. We know
this is what a proper nervous system looks like so it’s much
easier to notice when things go wrong.”
Discovery of cima-1
The majority of synaptic connections form in the
embryonic stages, and these connections remain as the
animals grow into adults. To address the question of how
C. elegans maintains embryonically specified synapses, the
Colón-Ramos lab searched for genes involved in synapse
maintenance through a process known as forward genetics.
In the forward genetic approach, random mutations are
chemically induced in the DNA of the organism, creating C.
elegans with a wide array of abnormal features. These mutant
organisms are then screened for particular characteristics of
interest. To target genes involved in synapse maintenance,
the Colón-Ramos lab isolated mutants exhibiting normal
synapses as larvae but misaligned synapses as adults.
To uncover the exact genes and proteins malfunctioning
in the mutants, the lab conducted genetic fingerprinting on
the mutants’ DNA, a process similar to paternity tests in
humans. The test pointed to a mutation in a gene called cima-1
as the cause of the abnormal synaptic connections. Prior to
this study, cima-1 had never been investigated in C. elegans.
To further confirm that cima-1 acts critically during growth,
the lab created mutations in the cima-1 genes of abnormally
21 Yale Scientific Magazine | November 2013 www.yalescientific.org
NEUROBIOLOGY
IMAGE COURTESY OF MIT
C. elegans, a common model
organism.
small and large
worms. “It
was a really fun
experiment,”
Colón-Ramos
noted. “We
had these
really giant
worms and
really tiny worms, and exactly as we predicted,
the small worms were less affected by cima-1
mutations and the giant worms were much
more affected. It’s fun when science works
like that.”
Glia and cima-1
Because mutations in cima-1 cause abnormal
neuronal connections, the logical prediction
would be that cima-1 acts in neurons.
Surprisingly, the Colón-Ramos Lab found
that cima-1 was found not in neurons but in
epidermal cells, which make up the outermost
layer of the skin. So how does a gene found
only in epidermal cells affect synaptic
connections between neurons? The answer,
as it turns out, lies in glial cells.
IMAGE COURTESY OF COLON-RAMOS
Epidermal cells (green) are in close contact
with glia (red) which are close to neurons
(green).
Glia often act as translators between
epidermal cells and neurons. Although
previously believed to be nothing more than
“glue cells” of the brain, we now know that
glial cells have an array of important functions
including supplying nutrients, providing
structural support, and fighting pathogens.
Furthermore, recent research has implicated
glial cells in a variety of neurodevelopmental
activities, including synapse formation. In the
neurodevelopment, epidermal cells position
the glia, and the glia in turn position neurons
and synapses. cima-1 mutants exhibited glial
cells with abnormal shapes, suggesting that
mutations in cima-1 interfere with proper
communication between epidermal cells and
glia, resulting in abnormal synaptic growth.
An analysis of the various molecules
involved in sending signals between epidermal
and glial cells identified a receptor regulated
by cima-1, suggesting that communication
through this receptor was the mechanism
behind synaptic maintenance.
From C. elegans to Humans
Although humans and round worms seem
to share very little in common with each other,
evolution has ensured that even the most
disparate of species share similar roots and,
consequently, genes. The human equivalent
of cima-1 is called sialin, and mutations in
sialin result in a neurological condtion known
as Salla disease. The defective sialin in Salla
patients results in a dangerous build-up of
a metabolic byproduct called sialic acid.
Build-up of sialic acid causes brain atrophy
and leads to an array of neurological problems
including mental retardation. Patients also
often suffer from motor control problems
such as reduced muscle strength, loss of
muscle coordination, and speech difficulties.
There is currently no cure for Salla disease,
and symptoms can be managed only to a
limited extent through medications and
therapy. Although Salla disease is relatively
rare, mutations in genes related to sialin
cause other human diseases such as gout and
congenital deafness. The Colón-Ramos lab
hopes that further investigation of cima-1
and its related mechanisms will result in the
discovery of novel therapeutic targets.
In addition to bettering our understanding
of various diseases, glial signaling may offer
insight into the evolutionary origins of the
human brain. Colón-Ramos pointed out that
the epidermal-glia-neuron signaling network
is reminiscent of the human blood-brain
barrier. During times of high activity, neurons
need more energy. Neurons communicate
this energy need through glial cells that are
in contact with epithelial cells of blood
capillaries. The result is increased blood
flow to the brain. The presence of the
epidermal-glia-neuron unit in C. elegans, as
well as the endodermal-glia-neuron unit in the
blood brain barrier of humans, suggests an
evolutionarily conserved role for glia in linking
epidermal (or endodermal) cells and neurons.
Future Directions
IMAGE COURTESY OF COLON-RAMOS
cima-1 (red) is found surprisingly not in
neurons, but in epidermal cells.
Although the discovery of cima-1 and its
role in neurodevelopment is a big step in
understanding synapse regulation, Colón-
Ramos noted that there are still many gaps left
to be filled. The implication that C. elegans and
humans may share the same fundamental glialneuron
unit also raises questions regarding the
evolutionary roots as well as functions of glia.
Although not all of these questions are ones
Colón-Ramos plans on pursuing, he hopes
that “our research will influence the way other
people and labs think about the role of glia
in neurodevelopment and maintenance of
neuroarchitecture”
About the Author
Somin Lee is a junior in Branford College majoring in Molecular, Cellular, and
Developmental Biology. She currently works in Professor Marvin Chun’s lab
investigating neural representations of sustained attention.
Acknowledgements
The author would like to thank Dr. Colón-Ramos for his time and insights, and
John Urwin for his clear explanations of complex topics.
Further Reading
• Ryan Christensen, Zhiyong Shao, Daniel A Colón-Ramos, The cell biology of
synaptic specificity during development, Current Opinion in Neurobiology,
Available online 6 August 2013, ISSN 0959-4388, http://dx.doi.org/10.1016/j.
conb.2013.07.004.
22 Yale Scientific Magazine | November 2013 www.yalescientific.org
So, what’s in your buffer
DOES matter!
Loria Lab Detects Solute Influence on Enzyme Motion
By Jayanth Krishnan
By Jayanth Krishnan
Professor Patrick Loria has always
been fascinated by the fundamentals
— internal motions in proteins and
the functions of those proteins in the body.
Enzymes, the proteins that work to catalyze
reactions, are certainly not static. The Loria
lab investigates the internal motions of
biological enzymes, an area of study that
is crucial to drug discovery efforts. Using
nuclear magnetic resonance spectroscopy
of proteins (protein NMR), the Loria lab
studied how phosphate, sulphate, and acetate
buffers can influence motions and illuminate
the functions and allosteric regulation of
enzymes.
Allosteric enzymes are proteins that
change their conformation when bound
to an effector protein. This change in
www.yalescientific.org
IMAGE COURTESY OF PATRICK LORIA
The Loria lab at Yale, with Professor Patrick
Loria standing third from the right.
conformation can either activate or inactivate
the enzyme. Although functional allosteric
enzymes regulate many classic pathways, the
biochemical mechanism of action of most
of these enzymes is still very unclear. The
Loria lab works in collaboration with Yale
Chemistry Professor Victor Batista, who
is an expert in computational chemistry,
to understand and rationally alter allosteric
enzymes.
Techniques and Tools of the Loria Lab
The Loria lab used NMR spectroscopy
extensively to analyze the influence of buffers
on enzyme motions. In NMR, the nuclei of
atoms, depending on whether they possess an
intrinsic form of angular momentum (spin
property), behave like small magnets.
Upon immersion of these atoms into
a static magnetic field of the NMR
spectrometer while maintaining exposure
to a secondary oscillating magnetic field,
an NMR signal is produced. This is a
physical phenomenon in which nuclei
in a magnetic field absorb and re-emit
electromagnetic radiation at a specific
resonance frequency. The chemical shift
of a nucleus is the difference between
the resonance frequency of the nucleus
and a standard reference compound
(e.g. tetramethylsilane, which is assigned
a chemical shift of zero). This quantity is
reported in parts per million (ppm) and
given the symbol delta, Δ. The chemical shift
differs for the various amino acids (residues)
of an enzyme. The protein NMR signal
helps scientists classify the protein and better
understand its dynamic properties.
The Loria lab measures spin-spin
relaxation times using relaxation dispersion
experiments, which are pulse sequences
applied during spectroscopy. The term
relaxation describes several processes by
which nuclear magnetization prepared
in a non-equilibrium state returns to the
equilibrium distribution. In other words,
relaxation describes how fast spins “forget”
the direction in which they are oriented.
Spin-spin relaxation is the mechanism
by which the transverse component of
the nuclear spin magnetization vector
exponentially decays towards its equilibrium
value of zero. The metric (R ex
), which is
commonly used to analyze results from the
relaxation dispersion experiments, depends
on conformational exchange parameters ϕ ex
and k ex
. The parameter ϕ ex
takes into account
the equilibrium population of a pair of
inter-converting conformers as well as the
difference in chemical shift between the two
conformations. The parameter k ex
is the sum
of the forward and reverse rate constant of
the conformational states.
November 2013 | Yale Scientific Magazine 23
BIOCHEMISTRY
IMAGE COURTESY OF MICHIGAN STATE UNIVERSITY CHEMISTRY DEPARTMENT
An NMR spectrometer: in the continuous wave method,
the sample is spun between poles of a powerful magnet. A
spectrum is acquired by varying the magnetic field.
Investigations at the Loria Lab
Imidazole glycerol phosphate synthase
(HisF), an allosteric enzyme needed
for the survival of plant pathogens and
some pathogenic bacteria, has been
studied extensively in the Loria lab. If the
mechanistic properties of this enzyme
are better understood, scientists could use
small molecules to inhibit the enzyme and
eventually provide a therapy for those affected
by the pathogen. Using protein NMR on
HisF, the team noticed chemical shifts that
changed based on the buffer being used. In
literature, the lab found research on the pH
dependence of atomic resolution structures
that complemented the solution NMR
experiments but found
very little work that
investigated how solute
and buffer molecules
interact to change
enzyme conformation.
The lab then embarked
on control experiments
to illustrate the
importance of choosing
the most appropriate
buffer as common
solute molecules can
alter observed enzyme
millisecond motion.
In a study led
by Madeline Wong ’13, the Loria lab
implemented solution NMR to examine the
effects of different functional groups in
the enzymes HisF, ribonuclease A (RNase
A) and triosephosphate isomerase (TIM).
Phosphate, sulfate, and acetate were used as
buffers as these functional groups have shown
a number of ways to interact with proteins of
interest. The effects of these buffers on the
chemical shift perturbation and millisecond
conformational exchange motions of the
enzymes were compared to the effects of
reference buffer systems HEPES and MES.
When the NMR experiments were performed
to examine chemical shifts and dynamics of
the three enzymes, the scientists kept the pH,
ionic strength, and temperature constant so
that the buffer was the only independent
variable. The researchers subsequently
performed relaxation dispersion experiments,
which showed significant solute-dependent
changes for all of the enzymes. Lastly, when
the X-ray crystal structure for all three
enzymes was analyzed, there was a significant
presence of phosphate ions at the enzymes’
active sites, clearly illustrating that an anionic
buffer could alter conformational dynamics
of enzymes. In future research, the lab will
perform enzyme assays with and without
different buffer components to see if buffers
can inhibit enzyme function.
Through the results of this study, the Loria
lab has illustrated the importance of buffers,
and how buffers can confound biochemical
experiments. “Typically buffers for
biochemical studies are chosen as a matter of
experimental convenience. What Madeline’s
experiments show is that buffers can play a
more active role, often altering the function
and dynamics of the system under study,”
stated Loria. Although addressing this issue
in the lab may be difficult, as even the best
buffers could affect enzymatic conformation,
these results have highlighted an important
procedural issue.
On a local scale, the results of Wong’s study
continue to inspire current Yale students. Tim
Caradonna ’15 is now starting his second
year in the Loria lab. When asked what drives
scientists such as himself in this type of
basic research, Caradonna stated, “The goal
of basic research is to solve fundamental
problems, which can provide an established
context for more applied research in the
future. Experiments such as Madeline’s are
important controls; if the buffer has changed
the dynamics of a protein, you’ve potentially
affected its function or activity.” On a larger
scale, knowledge of how buffers can affect
enzyme activity offers important insight into
the future of drug development and other
fields of biochemical experimentation.
About the Author
Jayanth Krishnan is a junior Molecular, Cellular, & Development Biology
major in Morse College. He is the journalism chair for the Synapse program of Yale
Scientific Magazine Outreach and works as a remote affiliate in Professor Kellis’ lab
at MIT.
Acknowledgements
The author would like to thank Professor Patrick Loria for his time and his enthusiasm
for his research.
IMAGE COURTESY OF PATRICK LORIA
Millisecond motion in the enzyme RNase
A. Amino acid residues with Rex ranging
from 0 (gray) to 40/s (red, see color bar)
are shown on a diagram of RNase A for
MES reference (A) and phosphate (B).
Further Reading
• Wong, Madeline, Gennady Khirich, and Patrick J. Loria. “What’s in Your Buffer?
Solute Altered Millisecond Motions Detected by Solution NMR.” Biochemistry
[http://pubs.acs.org/doi/pdf/10.1021/bi400973e]
24 Yale Scientific Magazine | November 2013 www.yalescientific.org
A Shattering Discovery:
Optimizing Microstructures
TO ENHANCE DURAB ILITY
BY DEEKSHA DEEP
Picture your ideal mobile phone — it
probably has a sleek design with a
polished screen and a slim but fragile
body. Now imagine that phone falling: either
off the edge of your bed, out of the car as
you open the door, or even clumsily out of
your hand as you pull it out of your pocket.
The sound and sight of a shattered screen
that would likely follow are all too familiar,
but what if there were a way to alter the
properties of the materials used in our devices,
our buildings, and the very infrastructure on
which our lives are based? Yale researchers
Professor Jan Schroers and Dr. Baran Sarac
have tackled this question by developing a
process to enhance the physical properties of
a material utilizing “artificial microstructures.”
The Importance of Microstructures
Every material has measurable physical
properties, such as tensile strength, ductility,
and plasticity. These properties can be
improved if a compatible microstructure
is coupled with the desired material.
Microstructures, which can only be seen using
optical microscopes, can function to absorb
stress, thus increasing a material’s strength and
durability. The key features of microstructures
include shape, size, volume, distribution, and
spacing between each individual element. If a
microstructure can be altered in a controlled
manner to produce a structure analogous to
a particular material, the material’s quality and
www.yalescientific.org
durability can be greatly improved.
An example of the utility of microstructures
is their role in improving the quality
of refractory materials. Useful for the
construction of industrial equipment such
as kilns, incinerators, and reactors, refractory
materials can withstand heat while retaining
durability. Embedding microstructures in these
materials greatly enhances their refractory
properties. Furthermore, increasing the
efficiency of materials decreases consumption
and costs. For example, since 1970, the US has
decreased its consumption, and by extension
waste, of refractories by over 64 percent.
Applications of microstructure biomaterials
used in hip replacements are not refractory
materials, they match in elasticity with the
body and are biocompatible. For example,
biomaterials (ex. hip replacements) to be
used in vivo need to match in elasticity with
the body parts they replace. The desired
mechanical properties can be achieved via
directed construction of microstructures.
With such drastic improvements in sight, there
is clearly incentive to further study and apply
microstructures to more materials.
Introduction to the Project
Professor Schroers and his team used a
class of material called Bulk Metallic Glasses
(BMGs) for their study on microstructures.
These materials mimic many properties
of metals but are far more resilient and
IMAGE COURTESY OF BARAN SARAC
Dr. Baran Sarac (left) and Professor Jan
Schroers (right) are the co-authors and
main researchers in determining the
optimal microstructure for BMGs.
surprisingly plastic, or moldable. This unique
conglomeration of properties makes BMGs
promising in many areas of application
from large structures down to nano-scale
projects. Unfortunately, there is a barrier to
the implementation of BMGs in improved
materials: They have a gaping lack of
tensile ductility, which prevent them from
being worked into a desired shape without
significant stress. This issue with what would
otherwise be a perfect candidate for the
future reshaping of materials was the focus
for the “artificial microstructure” approach
implemented by Schroers and his team.
November 2013 | Yale Scientific Magazine 25
MATERIALS SCIENCE
The Process of Discovery
Schroers’ “artificial microstructures”
approach is universally applicable to the study
of all microstructures, and not only to BMGs.
It strives to control individual characteristics
of the microstructure independently, allowing
isolated study and optimization of the
properties of each microstructure within the
overall material.
The technique of “artificial microstructures”
has both a distinct process of generation and
a unique method of implementation. Usually,
microstructures are applied onto the material
during the casting or heat treatment of the
IMAGE COURTESY OF BARAN SARAC
The tensile testing machine utilized to
determine the tensile ductility by which
the effectiveness of the artificial microstructures
can be quantified is shown in
the picture above.
material. However, artificial microstructures
are generated in a controlled manner on a
template, and are then transferred to the
metallic glass by reheating and pressing
the material. This method of applying
microstructures is more precise and efficient.
Schroers and his team analyzed the resulting
heterostructure using three different methods:
finite element simulation, a bending test, and
heat treatment. The finite element simulation
proved useful in modeling the mechanical
behavior under stress. The bending test
involved testing the behavior of the material
in the elastic to plastic strain region and
subsequently examining how the material
changed in bending ductility in a range of
strains. The heat treatment involved studying
the heterostructure under varying annealing
conditions and embrittlement to analyze
thermal and structural properties for elevated
temperature applications.
The project’s goal was to use the “artificial
microstructures” technique to determine the
factors in the microstructure that could imbue
the BMGs with tensile ductility. The BMGs
were studied in the soft, cellular phase, but the
technique’s effect on the hardened, composite
phase was also examined. By applying varying
parameters to the microstructures, Schroers
and his team found that the shape, volume,
and interfacial strength projected qualities
on the soft second phase that decreased
shear stress in the material. Furthermore,
the spacing of the microstructures and
relative size of the overall material were also
important in optimizing the tensile ductility
and toughness of the BMGs. Overall,
Schroers and his team were able to identify a
heterostructure that conferred tensile ductility
onto the BMGs.
Implications and Further Studies
Materials are an integral part of everyday
life, from the steel infrastructure of buildings
and bridges to the polymer plastics that are
used for garbage bins and kitchen appliances.
The cost of production and waste from such
usage of materials is also a significant part of
daily life. The work of Schroers and Sarac has
provided the industry with a new technique
for improving the efficiency and quality of
materials in a way that can be applied to
decrease waste and increase cost-effectiveness.
Not only are BMGs now more practical
for use, but this technique of microstructure
analysis can also be readily applied to other
materials. Microstructures can be designed-toorder
depending on the desired qualities in the
material, which opens up a wide horizon for
future applications of the technology. Sarac,
who co-authored the paper, recently obtained
his PhD from Yale with the completion of this
project and is continuing his study on BMGs
and their properties in Germany. At Yale,
Schroers and his team are investigating flaw
tolerance of metallic glass heterostructure
as an analogous system to microstructures
found in nature. Studying optimization
of microstructures via the novel artificial
microstructures technique in a lab setting
could reveal new information about how
nature optimizes its microstructures.
This research, uniquely situated in the
intersection of the artificial and the natural
and past and future of materials, has the
potential to change materials from being
limiting factors for innovation to being in
the forefront of innovative construction and
production.
About the Author
IMAGE COURTESY OF BARAN SARAC
Professor Jan Schroers’ lab, including
the equipment necessary to to construct
these artificial microstructures.
Deeksha Deep is a sophomore Molecular Biophysics & Biochemistry major in
Morse College. She works in the Spiegel lab studying cell surface reconstruction in
bacteria and vaccine design and is on the Yale Scientific Magazine business team.
Acknowledgements
The author would like to thank Dr. Baran Sarac for his time and for his enthusiasm
about his research.
Further Reading
Sarac B. and Schroers J. Designing tensile ductility in metallic glasses. Nat. Commun.
4:2158 doi: 10.1038/ncomms3158 (2013).
26 Yale Scientific Magazine | November 2013 www.yalescientific.org
CURRENT EVENTS
Sequestration Cuts into Scientific Research
BY ALEX CO
FEATURE
On March 1, 2013, the federal budget sequestration went into effect,
implementing the automatic spending cuts that the Budget Control Act
of 2011 had created two years ago. This fiscal year, reductions across the
board will total approximately $85.4 billion, with a $9.3 billion decrease
in federal R&D funding alone.
While the cuts spare no public sector, medical research is among the
hardest hit. The National Institutes of Health, the largest financier of
biomedical research in the world, was forced to make a five percent ($1.7
billion) budget cut by the end of September. It expects to fund only 15
percent of proposals received this fiscal year, a historic low from down
from its peak of 37 percent in 2001. Defunding such vital research and
development may threaten the quality of human health, curtail training
of the next generation of researchers, and jeopardize the United States’
position as one of the world’s leaders in science research.
A nationwide survey conducted by the American Society for Biochemistry
and Molecular Biology (ASBMB) asked more than 3,700 scientists
across a range of disciplines about the effects of the sequester on their
research. 80 percent of respondents indicated that they spend more
time writing grants than in 2010, while 67 percent receive less total grant
money than before. “The biggest time commitment now for investigators
is trying to get funding,” said Dr. Paul Lombroso, Director of the
Laboratory of Molecular Neurobiology at the Yale School of Medicine.
Lombroso also highlighted the dramatic increase in competition, with
many outstanding proposals competing for fewer funds. With less time
and fewer resources devoted toward conducting research, projects that
have been underway for years may be forced to end.
Because sequestration has only existed for several months, the
short-term effects have not been too substantial. Major agencies and
individual researchers report having
a slight cushion of funding for
the time being. But the future of
science research that looks solemn
if sequestration continues.
The lack of grant money will also
affect jobs, with many researchers
unable to hire new staff or
even keep current lab members.
Meanwhile, in a time of general
economic austerity, foreign governments
including those of the
United Kingdom, Sweden, and
Australia, among others, have committed
funds and political backing
to science. Thus, current and future
researchers in the United States
may soon have to make important
choices. Faced with ongoing funding
shortages, they may choose to
leave the country for greener pastures
— those nations with money
for research funding, and perhaps
more importantly, job security.
With dwindling job opportunities, the possibility of a so-called “brain
drain” is becoming more of a reality. Eighteen percent of respondents
in the ASBMB survey considered continuing their careers in another
IMAGE COURTESY OF DAILY KOS
While funding applications are on the rise, acceptance rates are
decreasing as the sequester reduces money to fund research.
IMAGE COURTESY OF CHECK KENNEDY
President Obama, a vocal opponent of sequestration, speaks at
Argonne National Laboratory outside Chicago. With Congress
unable to produce a budget and prevent a shutdown, the sequester
remains in place, spelling more trouble for the future.
country, where research jobs are more stable. For others who have yet
to select a career path, the prospect of science research has lost some of
its appeal, and the number of students who enroll in graduate programs
each year has declined sharply. As a result, projects with the potential
to change the lives of citizens across the country and around the world
may not be fully realized. With the threat of scientists leaving the United
States and the risk of students defecting to other, more stable professions,
the position of the United States’ leverage in science is precarious.
In light of federal funding cuts, researchers have turned to other tactics
for money. Researchers can seek “bridge funding” to tide themselves
over, and some have resorted to
especially creative means. HIV
researcher Yuntao Wu of George
Mason University is receiving
money from an online charity
drive set up by a non-profit organization.
But Wu, like some other
desperate colleagues, has also
taken out a $35,000 personal loan
to keep his lab open and continue
projects that he has worked on for
years. For others like Wu, options
are decreasing all around and the
state of future science research in
America remains unknown.
In light of the government shutdown
on October 1, the sequestration
will remain in place until
Congress passes a new budget that
explicitly redefines agency funding.
While sequestration is hurting science
now, the impact will be much
greater in future years if these cuts
in research funding continue and
researchers must continue and perhaps even intensify their austerity. It
remains to be seen if America’s quality of research will remain at its
influential level if money is not there to support it.
www.yalescientific.org
November 2013 | Yale Scientific Magazine 27
FEATURE
OCEANOGRAPHY
A Whole New World
Scientists Discover Abundant Viruses Living Under the Sea
BY PAYAL MARATHE
A single drop of seawater contains nearly ten million viruses.
But despite their strength in numbers, marine viruses failed for
decades to win the attention of most researchers. Scientists believe
that only one percent of all saltwater virus species have been identified
to this day.
Recent discoveries in this branch of microbiology are finally shedding
light on just how intriguing and powerful these viruses can be.
In fact, there are ten times as many saltwater viruses as there are all
other saltwater microbes combined, and their sheer number makes
them an incredibly powerful ecological force. By controlling bacterial
populations, marine viruses determine how much energy is available
for plants and animals in the world’s oceans. They can also benefit
research in agriculture, medicine, and evolution.
One significant breakthrough in the field came in February, when
Nature published a study led by Oregon State University microbiologist
Stephen Giovannoni. Giovannoni’s team identified a new species
of marine virus that attacks SAR11 bacteria, the most abundant
marine bacteria worldwide. This discovery might not come across as
astonishing. After all, 99 percent of marine viruses are still floating
around unidentified; ecologists who sift through saltwater are likely
to find something new eventually. And yet these new viruses, which
Giovannoni has found are the most abundant saltwater viruses in
the world, managed to escape discovery for decades.
The new viruses, dubbed “pelagiphages,” play a critical role in the
ecology of marine ecosystems, making it even more remarkable that
they remained hidden from the scientific community for so long. By
regularly attacking and killing SAR11, the pelagiphages prevent the
bacterial population from overrunning an entire ocean ecosystem.
Paul Turner, a Professor of Ecology and Evolutionary Biology at
Yale, explained that bacteria like SAR11 are extremely efficient at
using their resources. Without marine viruses to kill as much as 50
percent of saltwater bacteria every day, rampant bacterial growth
would quickly deplete the ocean’s resources.
SAR11 also happens to be a major player in the carbon cycle. The
bacteria absorb organic carbon from the environment in order to
produce energy, releasing carbon dioxide in the process. Although
each individual bacterium consumes a small amount of carbon,
the entire population uses up a tremendous amount of the organic
carbon molecules dissolved in seawater. Given carbon’s essential
role as a biological building block — it is a component of proteins,
lipids, carbohydrates and nucleic acids — it is crucial that plants and
animals have access to organic carbon from the environment. When
pelagiphages penetrate and kill the bacteria, this captured organic
carbon becomes available to other plants and animals in the water.
The inner workings of the pelagiphage resemble those of most
other viruses. Technically, the virus is not alive — instead, it relies on
a host cell to function and reproduce. It attacks its host, SAR11, by
penetrating the bacterial cell and inserting its own viral DNA. Once
it has control of the cell, it uses the cell’s machinery to make copies
of itself. The SAR11 host cell eventually bursts and dies, releasing
new copies of virus that are free to scatter and infect new hosts.
More importantly, when SAR11 bursts it releases carbon, among
other essential nutrients, into the environment.
In addition to uncovering the new virus’s role in the ecosystem,
These “peliphage” viruses hold key roles in marine ecology.
An electron micrograph of SAR11 bacteria.
28 Yale Scientific Magazine | November 2013 www.yalescientific.org
OCEANOGRAPHY
FEATURE
Stephen Giovannoni, the lead researcher of the Oregon State University team
that identified the most abundant marine viruses.
Giovannoni’s research highlights an ongoing evolutionary arms race
between SAR11 and marine viruses. Because of their fast life cycles
and quick reproduction, both microbes are able to evolve rapidly, and
according to Turner, they are the “champions of adaptive change.”
With each generation, the viruses are responding to SAR11’s evolutionary
advantages with changes of their own; meanwhile, SAR11
bacteria quickly adapt to any adjustments made by the viruses.
This evolutionary process is extraordinarily rapid. Viruses proceed
through an average of 1.2 generations per day. By contrast, observing
evolution in humans is impossible, because it takes decades for
multiple generations to elapse.
The arms race between SAR11 and its viral predator has been
used by scientists to explain the great diversity of marine microbes.
For instance, as SAR11 adapts to the virus, perhaps by developing
a less penetrable nucleus or establishing a counterattack, the single
strain could potentially diverge into multiple species.
Luckily, for each new bacterial strain that emerges, there are dozens
of viruses that have yet to be revealed. In July, researchers at the
University of Arizona identified twelve new types of bacteria-killing
saltwater viruses. “Studies like this convince us that we only know
the tip of the iceberg when it comes to the diversity of viruses in
natural environments,” said Turner.
Several months earlier, researchers at Cornell University added to
the growing list of discoveries in marine virology. The team identified
a species of saltwater virus that attacks crustaceans called copepods.
These crustaceans feed on photosynthetic phytoplankton, and the
pellets they release sink to the ocean floor. But these pellets are not
entirely waste — they include large amounts of locked-up organic
carbon that came from the phytoplankton. Once again, marine
viruses come to the rescue by controlling copepod populations and
maintaining suitable levels of organic carbon in the ecosystem.
Given the great variety of marine viruses, cataloging these species
is a tremendous step in revealing the diversity within underwater
ecosystems. “One of the ultimate goals for ecologists is to eventually
describe all the creatures on the planet,” said Turner. With such
vast quantities of marine viruses, it is impossible to pursue this goal
without exploring and identifying pelagiphages.
Of course, most people outside the field of ecology are not quite
so passionate about cataloging every creature on
earth, understanding the carbon cycle, or testing
evolutionary theories at high speed. However,
these newly discovered marine viruses have a
profound impact on other aspects of research.
For example, studying new viral specimens gives
scientists a better understanding of how viruses
can easily penetrate a host cell and navigate a
victim’s immune system. By studying this process,
researchers can potentially develop better antiviral
treatments to human and animal diseases.
Turner explained that other advantages of
marine viruses are less obvious, but just as
exciting. “We tend to only focus on viruses that
make us sick,” he said, “but, if we look at specific
viruses and at the specific genes that make
those viruses successful, we can take advantage
of viral functions for our own applications.”
IMAGE COURTESY OF KARL MAADSAM According to Turner, recent research has shown
that certain plants can grow more efficiently at
high temperatures when infected by a virus. This
ability can be harnessed to support plant growth
even as global warming threatens agriculture.
As research in marine viruses accelerates, Turner said he is optimistic
about where the field will go. There is still much work to be done
in cataloging the diversity of these saltwater viruses, and along the
way scientists can continue investigating the impact viruses have on
medicine, agriculture and biodiversity. Much remains to be explored
in that single drop of seawater containing ten million viruses.
www.yalescientific.org
November 2013 | Yale Scientific Magazine 29
FEATURE
GEOLOGY
Hidden Beneath the Ice
scientists discover mega-canyon in greenland
BY SOPHIE JANASKIE
In the past century, scientists and researchers have
explored the depths of the ocean, landed rovers on
Mars, and developed a deeper understanding of the
human brain and body. In the wake of these discoveries
and in the age of Google Maps and GPS,
one would think that we have explored all there is to
explore. However, a new finding suggests there may
be more left to discover than we originally thought.
A research group led by Jonathan Bamber of
Bristol’s School of Geographical Studies has recently
uncovered a never-before-seen mega-canyon in
northern Greenland. This massive geological feature,
which measures about 460 miles in length and up
to 2,600 feet in depth, stretches from the center of
Greenland all the way to the Petermann Glacier fjord
on the northern coast.
But how did this enormous canyon, which in
some locations is comparable in scale to the Grand
Canyon, escape our notice for so long? Simple: It is
buried under more than a mile of ice.
Most glacial researchers study coastlines, where the ice is most
unstable and most likely to affect the global sea level. Bamber’s team,
however, did not limit their scope so narrowly. Their study encompassed
the entire island of Greenland, drawing from the data of prior
studies across a 40-year period.
In the beginning, Bamber’s team had simply hoped to investigate
the portion of Greenland’s landscape that was hidden by ice. From
previous investigations, researchers knew that ice-covered geological
features were important, though unseen. Topography below glacial ice
affects the flow and path of meltwater, which are key in understanding
glacial movements and global sea level rise. In addition, landscape
features that predate the ice sheet can reveal important insights into
the history and geology of the region.
But when the team set its sights on Greenland, it certainly did not
expect to find anything of this magnitude. “You know, it’s not every
year, it’s not every decade, it’s not every five decades that you discover
IMAGE COURTESY OF NASA
NASA’s Operation IceBridge used an airborne radar to collect data
on the topography hidden beneath the ice sheet.
IMAGE COURTESY OF JONATHAN BAMBER
Radar data enabled Bamber’s team to produce a three-dimensional map of the
canyon’s topography.
something quite as substantial and extensive as a feature like this, so it
was a big surprise for us,” Bamber said in an interview with NPR. It
was not until they analyzed a significant portion of the data that they
noticed a large anomaly in the center of Greenland.
One of Bamber’s major data sources was NASA’s IceBridge, a sixyear
mission that monitored how Earth’s polar ice caps were changing.
IceBridge researchers employed an instrument called a multichannel
coherent radar depth sounder to carry out their survey. This device
emits ice-penetrating radio waves, enabling it to measure geological
characteristics of the bedrock beneath the glacier. Using this data,
Bamber’s team was able to generate a 3D map of the canyon’s landscape.
He found that over this area, radio waves took a much longer
time to bounce back to the radar device, indicating a large depression
in the topography.
Unlike valleys formed from glacial erosion, this mega-canyon is
not U-shaped. Rather, its sharply-defined features, meandering path,
and steep slopes suggest that a river once carved its way through the
bedrock. These characteristics place the canyon’s age at over four
million years old — the last time period when Greenland was not
covered in glaciers. These days, the canyon seems to play a key role in
the transport of the ice’s meltwater to the ocean.
The team’s discovery is a huge step for geological research because
it demonstrates that there is still much to explore on Earth. “One
might assume that the landscape of the Earth has been fully explored
and mapped,” said Bamber. “Our research shows there’s still much
left to discover.”
What else might be left? Although Bamber expressed doubt that
another geological feature of this magnitude remains hidden, he did
not rule out the possibility. Many landscapes hidden by ice sheets
remain unexplored and unstudied, as do other areas of our planet.
Whether it is the deep sea, ice sheets, remote islands, or high mountaintops,
this discovery leaves no doubt that we still have much left
to learn about our planet.
30 Yale Scientific Magazine | November 2013 www.yalescientific.org
ECOLOGY
FEATURE
Fly Guts Reveal Rainforest Biodiversity
BY WILLIAM GEARTY
A recent study lends truth to the saying that “you are what you eat.”
Dr. Sebastien Calvignac-Spencer, an evolutionary biologist at the Robert
Koch Institute, has found that the gut material of flies may be the key
to understanding the biodiversity of rainforests. By analyzing the DNA
in the digestive tracts of carrion flies, he has developed a new method
of monitoring and assessing mammalian biodiversity.
About one year ago, Calvignac-Spencer began studying sick chimpanzees
that were dying from a strain of rainforest anthrax in the Tai
National Park of Côte d’Ivoire. Since fly gut bacteria are known to
cause other strains of rainforest anthrax, he hypothesized that a similar
culprit was responsible for carrying and spreading this new strain. While
investigating the contents
of the suspect fly guts,
Calvignac-Spencer noticed
that 40 percent of the flies
yielded mammalian DNA.
This key observation
is what led to Calvignac-
Spencer’s latest study. As
scavengers, carrion flies
eat dead animals that have
fallen to the rainforest
floor. While the organisms
soon decompose,
fragments of their DNA
accumulate in the guts of
the flies. Unlike humans,
flies do not possess highly
acidic stomachs that they
churn their food in. Therefore,
the DNA will often
remain unbroken for long
periods of time. This DNA
can easily be recovered
from the captured flies
and matched with the species that it came from. “[The DNA is] not
gorgeous, but still usable,” he explained to Nature.
Calvignac-Spencer collected 201 carrion flies from his field sites in Tai
National Park, Côte d’Ivoire, and Kirindy Forest, Madagascar. His team
then extracted the DNA from the tropical flies, selecting the portions
containing sequences that most mammals are known to have. Finally,
by comparing the selected DNA sequences to libraries of animal DNA
sequences, Calvignac-Spencer was able to identify the various species
that the flies feasted on.
The list of species was surprisingly diverse. The flies from the Tai
National Park carried DNA from 16 mammal species, including local
primates, bats, a porcupine, a hippo, a shrew, and an extremely endangered
antelope. The search in Madagascar was also successful, yielding
four of the 31 total mammalian species on the island.
Although the group only gathered 201 flies, increased sampling could
produce higher recovery of mammalian DNA, increasing the percentage
of mammal diversity that these DNA censuses can account for.
To monitor animal populations, researchers usually have to spend
several years out in the field, counting specimens by direct observation.
It is time-, resource-, and labor-intensive. Furthermore, results of traditional
censuses can often become out of date very quickly, especially
taking into account the amount of time that is required to collect and
assess the data.
Calvignac-Spencer’s new method makes the process much more efficient.
Carrion flies are everywhere, and getting enough DNA samples is
far quicker than trekking through the rainforest in search of an elusive
species.
In addition to assessing a region’s overall biodiversity, Calvignac-
Spencer believes that analyzing fly guts can also be used to gather detailed
information on a single species.
For instance, by collecting
a large enough sample
of flies from a wide enough
range, this method could
potentially help researchers
determine the species’
distribution in the area.
Likewise, sampling over
a period of several years
could provide information
about the population’s
change over time, detecting
population crashes or
booms that would otherwise
be undetected by
conventional monitoring
methods.
In a discussion with
IMAGE COURTESY OF JJ HARRISON
Calliphora vomitoria: a type of meat-eating blowfly that Calvignac-Spencer
used in the 2013 study.
National Geographic,
Calvignac-Spencer cited a
case in 2002 when thousands
of gorillas were killed
by the Ebola virus in the
Republic of Congo. Standard monitoring only discovered 44 carcasses.
“Flies could really be precious in this context,” said Calvignac-Spencer.
Flies are not the only animals that can help monitor biodiversity. In
2012, Thomas Gilbert from the University of Copenhagen conducted a
similar study using leeches in Vietnam. Gilbert’s team was able to find six
mammal species including an extremely rare deer and a rabbit that had
never been seen in the area. Studies such as these, using new methods
of detection, may be the next step in understanding remote regions with
undiscovered life. “Unlike camera trapping and dung-searches,” Gilbert
told National Geographic, “leech data collection is simple, inexpensive
and can be conducted by untrained personnel.”
Calvignac-Spencer and Gilbert’s studies are part of the growing
research movement in environmental DNA (eDNA), the genetic litter
that animals spread throughout their surroundings. Since the early 2000s,
scientists in this new field have studied scraps of DNA that accumulate
in soil, water, air, and more recently, fly guts. While these methods are
still being fine-tuned, they may bring us closer to fully understanding
the scope of Earth’s biodiversity.
www.yalescientific.org
November 2013 | Yale Scientific Magazine 31
FEATURE
ENVIRONMENT
Mythbuster: The Great Pacific Garbage Patch
BY TARYN LAUBENSTEIN
IMAGE COURTESY OF CHARLES MOORE
This bird’s stomach contents are almost entirely composed of
plastics, which were the likely cause of its death.
From above the Pacific Ocean, all is calm. Blue water meets
blue skies, each reflecting the other’s pure, infinite depths.
But now a white scrap meanders by; not the reflection of a
cloud, but a bobbing Styrofoam cup. Soon it is joined by two,
now three, now ten, now fifty others, all jostling for space.
They start to stack, forming hills, mountains. They support
their plastic brethren: discarded bottles, packaging materials,
webbed fishing nets. Worn-out tires pile atop one another
forming rubber towers, while flimsy shopping bags flutter
like flags in the breeze. It is an island of plastic the size of
Texas, floating in the middle of the Pacific.
This is the image that comes to mind when people hear
of the Great Pacific Garbage Patch: a massive, floating heap
of debris. However, while it is true that trash does find its
way into the oceans, the Great Pacific Garbage Patch is not
a floating island in the traditional sense. Instead, the Garbage
Patch is composed of tiny plastic bits that linger unseen
beneath the surface, ranging in size from a few square inches
to barely visible specks.
Captain Charles Moore was the first to notice the Great
Pacific Garbage Patch in 1997. Then a racing boat captain, he was sailing
from Hawaii to southern California when he stumbled upon “plastic …
as far as the eye could see.” In an article he wrote for Natural History,
he described “plastic debris floating everywhere: bottles, bottle caps,
wrappers, fragments.” Seeking to quantify the extent of the debris, he
towed fine-mesh nets behind his boat, collecting the plastic bits along
with plankton in the water. He found that the mass ratio of plastic to
plankton was an astonishing 6:1.
Moore explained that the garbage patch was formed by a system of
ocean currents. In large ocean basins between continents, currents tend
to move in a circular pattern, known as a gyre. These wind-driven currents
push water towards the center of the basin. This means that any
pollution that enters the Pacific will eventually be pushed to the center
of the gyre, where it begins to accumulate. Of course, the Pacific gyre
is not the only ocean gyre — all of the world’s oceans have circular
currents like these. This means that there is not just one garbage patch,
but many; the two next-largest ones are found in the Northern Atlantic
and the Indian Ocean.
IMAGE COURTESY OF CHARLES MOORE
Captain Moore poses with a water sample taken from the Great Pacific
Garbage Patch.
While Moore’s description of ocean gyres holds true, his initial
description of the Great Pacific Garbage Patch has recently come into
question. He claimed to “never [have] found a clear spot” in the ocean,
perhaps leading to the hyperbolic tale of the floating island of garbage.
In 2008, seeking to debunk the myth, Dr. Angelicque White of Oregon
State University set off on a voyage through the heart of the Great
Pacific Garbage Patch. White’s team towed nets behind their boat, just
as Moore had, but their data told a different story. Yes, tons of plastic
were floating in the Pacific, but the vast majority of these plastic bits
were tiny, with 90 percent of them spanning less than 10 millimeters
in diameter. The Great Pacific Garbage Patch, therefore, is less of an
island and more a whirlpool filled with plastic confetti.
Despite the small size of the plastic bits, they can still have hugely
negative impacts on the marine ecosystem. While larger plastics like sixpack
rings can strangle marine animals, smaller plastics harm animals
from the inside. The plastic waste is small and transparent, and it floats
in the water column — just like plankton, which is a vital food source
for fish and marine mammals alike. Animals cannot digest plastic, and if
enough of it accumulates in their stomachs, they can die. Plastic can also
contain toxins like DDT and PCBs. Once ingested, these chemicals do
not break down, but build up in an organism’s body fat. As these organisms
are consumed by larger and larger organisms, the levels of toxins
increase dramatically, until those at the top of the food chain, including
humans, are eating fish and fowl with dangerously high levels of toxins.
Although the myth of the Great Pacific Garbage Patch as a floating
plastic island has been busted, the remaining facts are grim. Three ocean
basins are rife with plastics, marine organisms consume plastic instead
of plankton, and toxins climb up the food chain to humans. Is there a
solution in sight? Scientists like Moore and White hope so. Researchers
are currently working to understand the full scope of the garbage patches.
Still, consumers should take note: It is only by drastically reducing plastic
waste that the ocean gyres can hope to be cleaned for good. By choosing
products wisely and recycling, consumers can take small steps to make
the Great Pacific Garbage Patch into the Pacific that it should be: calm
and quiet, where blue water meets blue skies.
32 Yale Scientific Magazine | November 2013 www.yalescientific.org
NEUROSCIENCE
FEATURE
Debunking Science: Near Death Experiences
BY CATHY REN
IMAGE COURTESY OF SELF OBSERVED
Those who claim to have had near-death experiences often
report seeing a tunnel of bright light.
“On April 10, 2010, I was rushed to the hospital … I flat-lined …
my heart would not restart … It was during this time that I experienced
one of the most incredible phenomena that can be experienced
in one’s lifetime.”
This account is just one of many stories posted on the Near Death
Experience Research Foundation website. About twenty percent of
patients who survive cardiac arrest report having a near-death experience
(NDE) — they often recall seeing a tunnel of light, having
out-of-body experiences, being in a state of euphoria, or experiencing
other dreamlike events. Some who claim to have NDEs attribute
them to religion or the supernatural, but could there be a scientific
explanation for experiences like Cherie’s?
A new study conducted by Dr. Jimo Borjigin, Associate Professor
of Neurology at the University of Michigan, presents a possible
answer. In a previous project, Borjigin had noticed a neurochemical
spike in rats’ brains in the moments before their deaths, and she
became interested in what occurred in the brain at that particular
moment.
NDEs have long baffled scientists, who assumed that brain function
ceased during cardiac arrest. Previous hypotheses about the causes
of NDEs included hormone and neurotransmitter release, abnormal
activation of certain lobes of the brain, lack of oxygen in the brain,
and side effects of drugs. However, prior to Borjigin’s study, which
was published in August, the neurophysiological state of the brain
immediately following cardiac arrest had never been formally studied.
Borjigin and her team implanted six electrodes each into nine rat
brains in order to record brain activity at the brink of death. The rats
were anesthetized, and cardiac arrest was induced with injections of
potassium chloride. In the critical thirty seconds between the last
heartbeat and the shutdown of all brain activity, the team used a
device called an electroencephalogram (EEG) to record the frequency
at which the rats’ brain cells fired electrical signals. Immediately after
the rats entered cardiac arrest, overall brain activity decreased, but
the EEG detected an increase in a particular type of high-frequency
signal known as the gamma wave. “We weren’t surprised that we
www.yalescientific.org
found brain activity but we were surprised by the high degree of it,”
said Borjigin in an interview with National Geographic.
EEGs generally measure waves of five different frequencies: alpha,
beta, gamma, delta, and theta. Each wave is associated with a different
state of consciousness. Strikingly, gamma waves are correlated with
extreme focus, whole brain activity, and sudden insight — qualities
which may have been present in the near-death rats.
Along with an increase in gamma wave activity, the researchers also
noticed information transfer between neurons in the front and back
of the brain. They interpreted this activity as a possible sign that the
rat brains were forming organized thoughts. Furthermore, the EEG
detected organized activity among other brain wave frequencies.
Though not as prominent as the gamma waves, these suggest that
the near-death brain activity included different levels of consciousness
and was even more complex than that of a normal brain. This
extraordinary electrical commotion during cardiac arrest may serve
to explain these accounts of NDEs.
Borjigin’s results are certainly interesting, but there are still limitations
and confounding variables in the experiment. For one, the
anesthesia performed on the rats may have affected brain activity.
Furthermore, physician Sam Parnia doubts that researchers can
directly make the jump from signs of consciousness in rat brains to
near-death-experiences in humans. “There is no animal model of a
near-death experience,” he said in an interview with Science.
Though the findings are preliminary, researchers hope that the
outcomes may lead to future studies on the human brain. Borjigin
suggests monitoring EEG activity in patients undergoing brain surgery,
a procedure which has led to NDEs in the past, to see if the
findings from studies in rats can be applied to humans.
Whether or not near-death experiences are actually caused by
heightened brain activity in humans is yet to be determined. However,
the results of the study open the doors to further investigations in
the field. Perhaps we will soon find the answer to a question that has
long been shrouded in mystery and enigmatic anecdotes.
IMAGE COURTESY OF TRANSCENDENTAL MEDITATION
Electroencephalograms (EEGs) record waves of different
frequencies, including alpha and gamma waves. Gamma wave
activity spiked in the tested rats’ brains after cardiac arrest.
November 2013 | Yale Scientific Magazine 33
FEATURE
UNDERGRADUATE PROFILE
Out of this world: Jan Kolmas TC ’14
BY ELEANOR SUN
For many of us, the phrase “mechanical engineering” evokes images
of complicated diagrams and dreadfully hard physics problems. For
Trumbull senior Jan Kolmas, however, engineering embodies not just
an academic subject but also a lifelong passion.
Hailing from the Czech Republic, Kolmas became interested in
engineering in middle school, where he displayed a natural aptitude
for quantitative sciences. “I always liked making things,” said Kolmas,
“and I always liked math and physics in high school. That sort of led
me to consider mechanical engineering because it’s a form of ‘very
applied physics.’”
To Kolmas, one of the most irresistible things about mechanical
engineering is its role in aerospace. During his freshman year, Kolmas
found a creative way to compensate for Yale’s lack of an aerospace
major by co-founding the Yale Undergraduate Aerospace Association
(YUAA). Through the YUAA, undergraduates interested in aerospace
can work on projects that they design themselves. “For two years, we
were building high altitude balloons, taking pictures from near space,”
recalled Kolmas. “Last year, we transitioned to building rockets and
UAVs [unmanned aerial vehicles]. This year we’re expanding on a
rocket experiment and doing more advanced rockets and propulsion
research.”
Although the YUAA was founded less than four years ago, Kolmas
and his teammates have already met with great success. In addition
to being one of the largest engineering student-run organizations at
Yale, the YUAA team also won the Astro-Egg Lander event in the
Battle of the Rockets Competition this year.
Outside of aerospace, Kolmas has explored other aspects of
mechanical engineering through research. During the summer after
his freshman year, he worked in the GRAB Lab at Yale, a group that
specializes in robotics. “Imagine someone who had an accident or
who is rehabilitating from an injury,” said Kolmas. “I was helping
build an exoskeleton, or a brace for the knee, that would help you
walk without placing stress on the knee.” This past summer, Kolmas’
research took him all the way to Delft University in the Netherlands,
where he studied mission reports from small satellites. By determining
which components of small satellites were most vulnerable to failure,
he worked to find troubleshooting and repair methods that would
minimize satellite failures in the future.
In addition to research, Kolmas developed his interest in aerospace
by participating in the 2013 Caltech Space Challenge, an event that
brings the world’s top engineering students together in a competition
to design the best space mission. “I think there was a poster on campus
that first caught my attention, and I thought, ‘Hey, this is something
I’d be really interested in,’” said Kolmas. After undergoing an intensive
application process, he was selected as one of the thirty-two competitors
and placed onto Team Voyager with fourteen others.
Under the guidance of Caltech professors and NASA professionals,
Kolmas and his teammates drafted a research proposal for NASA on
a human mission to a Martian moon. The proposal, completed in
just five days, encompassed research goals in astronomy and biology.
Some of these goals included determining the origin of the Martian
moons, testing food cultivation in a different gravitational setting,
and investigating the effects of radiation exposure and stress on
the human system. After presenting its plan to a grand jury, Team
IMAGE COURTESY OF JAN KOLMAS
The launch of the 2013 Astro-Egg Lander winner, the rocket
YSS Eli Whitney.
Voyager emerged victorious. “I met a lot of interesting people
from the field that I want to work in,” said Kolmas. “I made lots of
contacts at different schools, so I have more of an insight on what
I want to do.”
Besides being a brilliant engineer, Kolmas is also a sports enthusiast.
He swam all four years at Yale on the club team, serving as captain
for two years. Additionally, he spearheads Trumbull’s IM endeavors
as the volleyball and water polo captain. “I would say that water polo
is my favorite sport because it’s so unusual,” said Kolmas.
Currently finishing up his last year at Yale, Kolmas plans to obtain a
master’s degree in aerospace engineering after graduation but is open
to accepting a job offer if the circumstances are right. His dream job?
“Probably ground control for a space station,” said Kolmas.
IMAGE COURTESY OF JAN KOLMAS
Kolmas, an enthusiastic and accomplished athlete, has run a
Half Ironman Triathlon.
34 Yale Scientific Magazine | November 2013 www.yalescientific.org
ALUMNI PROFILE
FEATURE
At Home in the Wilderness: Yenyen Chan SY ’94, F&ES ’01
Yenyen Chan fell in love with Yosemite National Park
while exploring its wilderness and vistas during a high
school field trip. Now, after graduating from Yale College
and the Yale School of Forestry and Environmental
Studies, she has returned to the place where it all began:
As a United States Park Ranger in Yosemite, Chan works
to pass her knowledge and enthusiasm about the natural
world on to the next generation of park visitors.
Before coming to Yale, Chan was already interested
in environmental studies. Her courses in environmental
history and policy only solidified this focus. “Professor
John Wargo, who later became my advisor at the Forestry
School, really opened my eyes to the environmental policy
issues facing the country,” reflected Chan.
After a summer internship with the Natural Resources
Defense Council, Chan spent a few years at an
environmental consulting firm in Hong Kong. By working
in a region undergoing rapid development, she gained a
more global view of topics such as waste, water and air
pollution, and corporate environmental stewardship.
Looking back on her time at the Forestry School, Chan’s
recollections mirror the giddy faces of most students in
Kroon Hall today. “I loved it,” she said. “All of us in
this field want to do this work because it’s something
we love and because it’s critically important, both
socially and environmentally.” After gaining a Masters in
Environmental Policy and Resources Management, Chan
landed a position with the Yosemite Institute as a field
science instructor, and became a park ranger a year later.
Now, even after ten years of working in Yosemite,
Chan’s life as a park ranger is never dull. “There is no typical day,” she
said with a laugh. Her activities range from leading visitors on full-day
hikes to giving star and campfire programs at night, and she spends
much of her time teaching visitors about the rich history of Yosemite.
While Chan works much of the year in Yosemite Valley, she spends
the summer months in her favorite part of the park, Tuolumne
Meadows. Open to visitors from June to October, the meadows are
nestled in the Sierra Nevada mountain range at 8600 feet above sea
level, and characterized by breathtaking sub-alpine meadows and
peaks. To nature-enthusiasts like Chan, the beauty makes up for the
accommodations. “I live in a rustic tent cabin,” she explained. “Cold
running water, electricity, and a tarp roof over my head — it’s pretty
primitive.”
In addition to working in the field, Chan conducts educational
programs pertaining to subjects such as geology, history, resource
conservation, and climate change. For instance, in 2011 she created
a project that chronicles the history of Chinese laborers in Yosemite.
“There wasn’t much research about the topic,” Chan explained, when
she was asked to teach visitors about early Chinese contributions to
the park. Eventually, she co-produced a short park video on the topic.
Chan is also one of several park rangers participating in a multi-year
collaborative project between NASA, the Fish and Wildlife Service,
and the National Park Service on communicating climate change
science to park visitors.
BY ZOE KITCHEL
IMAGE COURTESY OF YENYEN CHAN
As a field science instructor and park ranger, Chan leads long, full-day
hikes and educates visitors on the history of Yosemite National Park.
Chan, a strong advocate of environmental consciousness, believes
that one of the parks’ most important roles is to educate visitors.
“The environment is important for our health and the health of the
planet,” she said. Her mission as a park ranger is two-fold; she strives
not only to share the beauty of the park with visitors, but also to make
them aware of the various threats that endanger its survival—invasive
species, habitat changes, diminishing snowpack, and wildfires, to name
a few. “To experience nature is both inspiring and humbling, and it
helps people take into account how important it is to have places like
this,” said Chan.
Although her work is primarily as a naturalist and educator, Chan’s
interests also lie in of environmental policy, especially the intersection
between public and environmental health. “Working with a national
environmental organization such as the Natural Resources Defense
Counsel or the Environmental Defense Fund still potentially lies in
my future,” she said. But for now, she is content to share one of the
country’s most beautiful places with visitors from across the world.
According to Chan, “It’s wonderful to see them experience it all.”
The temporary closure of National Parks this October due to the
government shutdown reminded the country how, as Chan explained,
“We depend on Congress to fund these places.” However, government
support is supplemented and shaped by public support. The recent
celebration of Yosemite’s 123rd birthday brings another statement of
Chan’s to mind: as she put it, “It’s a park for everyone.”
www.yalescientific.org
November 2013 | Yale Scientific Magazine 35
FEATURE
ECOLOGY
Urbanization Boosts Brain Size in Animals
BY STEPHANIE MAO
From day-to-day observations, the environmental impacts from
human activity are not so obvious. However, a collection of satellite
images from 1984 to 2012 speaks volumes: in the course of only three
decades, much of Earth’s verdant landscape has gradually given way to
gray cities, marking the long-term impact of urbanization. For better
or for worse, humans have distinctly altered their natural surroundings,
forcing other species to either adapt or go extinct.
It is not easy to develop new habits for a new environment. Many
animals have been compelled to adjust their behavior, gradually learning
to avoid, outsmart, or even befriend their new urban neighbors. Now, a
recent study conducted by University of Minnesota biologist Emilie C.
Snell-Rood and undergraduate Naomi Wick suggests that some animals
have adapted to the presence of humans by developing bigger brains.
In their study, Snell-Rood and Wick focused on local animal specimens
collected at the University of Minnesota Bell Museum. By measuring
the breadth, width, and height of various mammal skulls, they were
able to estimate the size of the species’ brains. Remarkably, in the
IMAGE COURTESY OF M. L. CAMPBELL
A white-footed mouse is one species in the study that displays
a difference in brain sizes between urban and rural populations
of animals.
white-footed mouse and the meadow vole, they found that specimens
from the city displayed a 6 percent increase in brain capacity over their
rural counterparts.
Snell-Rood provides two possible explanations for these findings. An
increase in nutritional quantity and quality, which urbanization provides
to some extent, may give animals the energy required to maintain larger
brains. However, the increase in skull size was not accompanied by an
increase in body size, making this theory less likely. A more probable
and interesting hypothesis is that adapting to human activity places a
larger demand on cognitive skills, such as foraging for food and interacting
with humans.
The growing impact of city environments on animal behavior, a
trend dubbed “synurbanization,” is well-documented. By destroying or
radically transforming natural habitats, cities create new, unfilled niches
and force local species to adapt. Studies of resulting animal behavior
report changes such as increased friendliness toward humans, new
nesting preferences, and longer waking hours. For some city-dwelling
animals, humans have also become a primary supplier of food. As human
metropolises continue to grow, the effects of synurbanization have been
conspicuous and profound. Snell-Rood’s study, however, is the first
that points to a possible link between behavioral change and brain size.
An additional finding in the new study suggests that the influence of
IMAGE COURTESY OF JENNIFER SIMONSON
Evolutionary biologist Emilie Snell-Rood examines shrew
specimens at the University of Minnesota Bell Museum.
human activity extends beyond cities as well. According to Snell-Rood’s
measurements, four rural species exhibited a boost in brain size, revealing
that they, too, may have been affected by changing environments. For
instance, an impact like deforestation may force bats in the countryside
to change their feeding and roosting habits.
Snell-Rood’s discovery is not the first time scientists have found evidence
of human activity driving animal evolution. In London, industrial
pollution gave dark peppered moths an advantage over the lighter ones,
enabling them to blend in with layers of soot. By contrast, the white
peppered moths, which once blended in with tree bark and lichens,
lost their evolutionary advantage and became less common. A second
example of human-driven evolution is a type of anole lizard, which
developed shorter legs to adapt to urban areas in the Bahamas. While
long legs are suitable for perching on wide surfaces, shorter legs better
equip the lizard to climb the narrow stalks that are typical of urban plants.
While Snell-Rood’s findings are significant, additional research needs
to be conducted on other specimens to determine whether the trend
continues in other regions. The age of the museum collections is also
an important factor, as the Minnesota researchers could only study
specimens from the past century — the brain sizes of animals that lived
before major industrialization remain unknown.
Still, the results are striking in their implications. The evolution of
bigger brains in animals sheds new light upon how deeply our actions
affect the surrounding ecology. We humans are not the only ones who
have adapted to our environment, developing tools and technology to
master nature. It turns out that the animals around us are adapting too
— and some in unexpected and surprising ways.
36 Yale Scientific Magazine | November 2013 www.yalescientific.org
TRIVIA
FEATURE
1
Black Holes Are Bright
The phrase “black hole” is both dramatic and memorable,
but it is not entirely accurate. Black holes are not the shadowy
voids portrayed in science fiction — in fact, they produce tremendous
amounts of radiation. This is because black holes act more like drains
than like magnets. Matter caught by their pull is not pulled directly
inward; instead, it circles around as if caught in a whirlpool. This swirling
process traps large amounts of stellar gas, spinning it around the
black hole at high speed. The result is an accretion disk: a rotating field
of imprisoned gas particles whose movement produces great friction
and strong magnetic fields. In turn, these forces produce X-rays which
we can detect on Earth with our instruments. These X-rays allow us
to see “black” holes, bright and clear.
2
Black Holes Are Loud
To our instruments, black holes are far from black, and
research suggests they are also far from silent. Black holes
exert an incredibly powerful gravity field, which pulls in stellar matter
at nearly the speed of light. Such fast-moving matter gains a tremendous
amount of energy, and this energy does not vanish past the event
horizon. Instead, as an object is pulled into a black hole, the energy
of its motion is
transformed
into sound. We
cannot hear
these sounds,
as space is
silent, but we
can “see” them
with our telescopes.
Sonic
waves emerging
from a black
hole produce
ripples in the accretion disk, and by analyzing these ripples, we can
determine their frequency. Incredibly, black holes produce the deepest
“notes” in the universe — 57 octaves beneath middle C.
3
Black Holes Are Messy Eaters
The pull of a black hole is commonly believed to be inescapable.
To some extent, this is true — once past the event
horizon, even light cannot emerge. But material circling the hole is not
always doomed. In fact, over 99 percent of it may escape. Why? Some
black holes, it seems, “spit out” their food. Our galaxy’s core contains a
massive black hole, one that behaves in unusual ways. Most large black
holes are constantly growing and emitting massive amounts of light. By
contrast, the Milky Way’s resident black hole is surprisingly dim. The
Five Things You Didn’t Know
IMAGE COURTESY OF NASA
X-ray image of a black hole’s sonic vibrations.
About Black Holes
By Ethan France
You’ve heard of black holes. They’re massive, they’re dense, and they can be inescapable
even at the speed of light. But did you know that they sing, glow, and spit
out their food? If not, read on!
cause is gas ejection — instead
of absorbing the stellar clouds
that circle it, the black hole is
launching most of them back
into space. Thus, while the hole
should be swelling and radiating
light, it has instead begun
to “starve.”
4
Black Holes
Are Cannibals
Because they need
“food” to survive, black holes are far from picky eaters. Their gravitational
fields attract anything with mass, and nothing is more massive
than other black holes. When two of these giants collide, neither is consumed.
Instead the two merge and become even larger. This kind of
fusion produces the greatest black holes of all, the behemoths we call
“supermassive.” These black holes are so large and their gravitational
fields so strong, that their accretion disks spin like particle accelerators.
Matter whirls around the event horizon at half the speed of light.
5
Black Holes Have Earthbound Relatives
Thankfully for us, black holes are restricted to deep space,
not on or near Earth. But the oceans produce surprisingly
similar phenomena known as eddies. Formed when currents bend back
on themselves, eddies are
“islands” of water swirling
in the middle of an
ocean. Small eddies, like
the “whirlpools” formed
by a canoe paddle, last
only a few seconds. The
largest can be hundreds
of kilometers wide and
may survive for years at
a time. Like black holes,
these gigantic eddies draw
in and collect anything
that approaches, trapping
it until they disintegrate
months later. Eddies also
create their own “accretion
disks” of water spray,
which floats above the current
but does not fall in.
IMAGE COURTESY OF STARDATE
A star feeds gas into a nearby
black hole’s accretion disk.
IMAGE COURTESY OF NASA
Satellite image of a massive eddy
near Japan.
www.yalescientific.org
November 2013 | Yale Scientific Magazine 37
FEATURE
BOOK REVIEWS
Brilliant Blunders:
From Darwin to Einstein — Colossal Mistakes by Great
Scientists That Changed Our Understanding of Life and the Universe
BY ZACHARY MILLER
We are apt to think that science proceeds as a steady, unceasing succession of “Eureka!” moments.
But as Mario Livio reveals in his wide-ranging and fast-moving book, Brilliant Blunders: From Darwin to
Einstein, even the most celebrated minds in history fumbled on a regular basis.
Livio’s book is adequately written, impressively researched, and surprisingly broad in scope — though
sometimes so broad as to seem haphazard. He begins by skimming through some of history’s most
interesting blunders and blunderers, from Aristotle and Marx to the Nazi High Command. This introduction
is followed by an in-depth exploration of the great mistakes committed by five scientists better
known for their groundbreaking intellectual successes. For instance, we learn about how Darwin’s theory
of inheritance came close to undermining his theory of evolution and about how Linus Pauling failed
to remember basic chemical principles in his model of DNA.
But far from just cataloguing scientific slip-ups, Brilliant Blunders is largely devoted to praising their
worth. Livio shows us that mistakes often fuel progress, just as Lord Kelvin’s erroneous estimates of
Earth’s age still succeeded in raising the bar for scientific rigor.
Along the way, Livio probes some deeper issues in the philosophy of science and establishes himself
as a skilled storyteller. The balance is decidedly in favor of the trivial over the profound, though, and
for this reason Livio’s book can end up feeling hollow. Still, it is an entertaining read and a unique and
more human perspective on some of the loftiest figures in science.
Rating: &&&&&
The Eternal Darkness
Packing for Mars
BY AVA MARIE HUNT
Rating: &&&&& BY MADELINE POPELKA Rating: &&&&&
From our earliest days to our more recent Star Trek TNG marathons,
the mysterious realm of outer space has held us earthlings in its thrall.
However, it is not necessary to board a spaceship in order to access an
unknown world. To this day, the depths of the earth’s oceans remain
just as enigmatic as any distant nebula. Robert Ballard captures this
alien landscape in his book The Eternal Darkness: A Personal History of
Deep-Sea Exploration.
Ballard’s work does not fit any conventional
definition of genre. It is at
once a memoir, a history, and a call to
action. In it he describes the history
of ocean exploration, beginning with
the invention of the earliest diving
craft. As he works his way through
more recent endeavors, Ballard also
includes his own adventures in the
field, such as his personal accounts
of mapping the Mid-Atlantic Ridge
and retrieving an inactivated nuclear
bomb off the coast of Spain, which
are richly imbued in narrative form.
Although much of his work reads
like an adventure story, Ballard does include sobering reflections on
the dangers inherent in ocean exploration. He challenges the reader
to weigh the benefits of scientific advancement against its potential
risks, calling for a paradigmatic shift in how we approach exploration.
Despite brief moments when the text borders on being overly technical,
the book is overall a fast-moving read. Ballard weaves his own
journey, from boyhood daydreaming to his famous discovery of the
Titanic wreckage, together with the stories of other intrepid pioneers,
creating an intimate picture of our quest to understand the oceans.
In Mary Roach’s Packing for Mars, the life of an astronaut is surprisingly
unglamorous. From embracing minuscule living spaces for
months on end to accepting the horrors of zero-gravity showers,
Roach illustrates the fascinating trials that intrepid space explorers
must learn to overcome. With entire chapters devoted to motion sickness
and astronaut hygiene, she describes the dark details involved in
each step of getting to space.
While the book has Mars in the
title, the bulk of Roach’s writing
actually summarizes trips to the
Moon and the International Space
Station, as well as isolated simulations
on Earth. Only briefly does she
cover the current efforts to transport
humans to Mars.
Nevertheless, Roach’s descriptions
of space travel are nauseatingly
effective. She drifts into lurid detail
when she describes the psychological
challenges of life on a space shuttle,
for instance citing the story of a
deprived astronaut who smuggled
casks of vodka into space.
Packing for Mars is not a how-to manual on traveling to our red
neighbor. Rather, it is an attempt to humanize a profession shrouded
in legend. For the most part, it succeeds. Roach occasionally stumbles
by fixating on scandal over substance; however, even the bizarre case
of the astronaut who drove across the country in diapers to accost her
lover does not detract too much from Roach’s message. The majority
of the book remains packed with humorous and enlightening insights
on life away from Earth.
38 Yale Scientific Magazine | November 2013 www.yalescientific.org
CARTOON
FEATURE
Frontier’s End
BY CELINA CHIODO
www.yalescientific.org
November 2013 | Yale Scientific Magazine 39