INQUIRY

New York University • College of Arts and Science
higher in urban ecosystems than rural ones. However, the
relationship between tree diversity and avian diversity is
not well studied. This project examined the richness and
composition of tree and avian communities in 18 green
spaces covering 8000 acres in New York City to determine
if a relationship between tree and avian diversity exists.
Estimated tree species richness across all green spaces was
52 species: 33 native and 19 non-native. Tree richness is
not evenly distributed among the spaces, with some spaces
having as few as one tree species. Avian richness values
were gathered from the citizen-science database eBird,
which describes real-time data on bird distribution. Bird
richness was compared between green spaces with varying
size and tree richness. Preliminary results have shown that
large green spaces with more diverse tree species support
a more diverse community of birds and have identified
three invasive bird species that occur in nearly every space.
Structure-Function Relationships in a Novel Class of
Small-Molecule Cancer Chemotherapeutics
Kaustabh Basu, Chemistry
Sponsor: Professor James Canary, Chemistry
Small-molecule drugs offer an interesting way to
deliver targeted therapy to cancer tumors while minimizing
side effects and damage to healthy tissues. This
project reports on a novel compound known as C45Na,
which displayed more than 90% inhibition of melanoma
and breast cancer growth in vivo. However, the drug was
found to vary in activity at pharmaceutical concentrations,
and its effectiveness in mouse models appeared to depend
on the method of preparation. This project first details the
methods by which it was discovered that C45Na forms
large-scale aggregates in solution and that these aggregates
are influenced by the method of sample preparation. The
second phase of the research utilized synthetic chemistry
to design a range of new drug molecules structurally similar
to C45Na, which would be more soluble and whose
effects would help point to the intracellular mechanism by
which C45Na and similar compounds act to inhibit tumor
growth. Through a combination of synthetic and analytical
chemistry and biological assays upon newly synthesized
molecules, significant progress has been made towards
developing this new class of potential chemotherapeutics
and, more importantly, towards a fuller understanding of
its mechanism of action within the cell.
The Role of the Repressor Tramtrack (Ttk) in Timing
the Developmental Program of Drosophila
Tim Bishop, Biology
Sponsor: Professor Stephen Small, Biology
The development from an embryo into a multicellular
adult with many cell types and complex organs requires
a tremendous amount of molecular control. Most of this
development is regulated by proteins called transcription
factors (TFs) that directly bind to DNA in regions called
cis-regulatory elements (CREs) and regulate gene expression.
In the fruit fly Drosophila melanogaster, a TF called
Bicoid is responsible for head development and patterning
of the embryo along the anterior-posterior axis. Bicoid
activates expression of a hierarchical system of segmentation
genes that are expressed into finer and finer stripes,
which ultimately control the placement of body structures
in the adult fly. Organization of these genes is controlled
by combinatorial input of Bicoid activation and a system
of repressors. Among these repressors is Tramtrack (Ttk), a
TF with multiple effects on early embryo segmentation and
decisions on cell fate and organogenesis. Ttk binding sites
have been found in the regulatory regions of a number of
known Bicoid target CREs. In initial experiments, removal
of Ttk binding sites from these CREs led to expression of
the target genes that were normally inactive in the embryo.
The effects of these Ttk binding sites on the transcription of
these genes will be further assayed by performing similar
experiments in which Ttk binding sites are removed and
added from Bicoid target CREs. Also, the expression of
segmentation genes will be measured in flies lacking Ttk.
The preliminary work suggests that Ttk’s activity as a
repressor is necessary to ensure proper temporal expression
of Bicoid targets, with CREs containing strong Ttk
binding sites being repressed longer than those with weaker
Ttk binding sites.
Investigating the Mechanism of Singlet Fission using
Coherent 2D Electronic Spectroscopy
Ilana Breen, Chemistry
Sponsor: Professor Daniel Turner, Chemistry
Singlet fission, a process discovered at NYU in the
1960s, has aroused renewed recent interest because of
its potentially robust applications, including solar cells.
Singlet fission is a photochemical, spin-allowed process
in which a singlet electronic state converts to two triplet
states. The phenomenon is rare but can be observed in
special molecular crystals, where a chromophore in an
excited state shares its energy with a neighboring chromophore
and thereby yields two triplet excited states.
This research aims to show that coherent 2D electronic
spectroscopy can provide insight about the mechanism of
singlet fission. Specifically, it aims to study how vibrational
modes affect the decay process. Since polyacenes and
other conjugated molecules are known to undergo singlet
fission, anthracene, tetracene and rubrene have been crystallized.
The crystals were grown through vapor deposition
in a homemade sublimation apparatus and characterized
through microscopy, X-ray crystallography, fluorescence
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