Introduction Guide to Biotechnology - Biomolecular Engineering Lab

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since the 1950s. Although the 1997 debut of Dolly, the
cloned sheep, brought animal cloning into the public consciousness,
the production of an animal clone was not a new
development. Dolly was considered a scientific breakthrough
not because she was a clone, but because the source of the
genetic material that was used to produce Dolly was an adult
cell, not an embryonic one.
Recombinant DNA technologies, in conjunction with
animal cloning, are providing us with excellent animal
models for studying genetic diseases, aging and cancer
and, in the future, will help us discover drugs and evaluate
other forms of therapy, such as gene and cell therapy.
Animal cloning also provides zoo researchers with a tool
for helping to save endangered species.
There are two different ways to make an exact genetic copy
of an organism such as a sheep or a laboratory mouse.
Artificial embryo twinning (AET) is the old-fashioned
way to clone. AET mimics the natural process of creating
identical twins, only in a Petri dish rather than the
mother’s womb. Researchers manually separate a very
early embryo into individual cells and then allow each cell
to divide and develop on its own. The resulting embryos
are placed into a surrogate mother, where they are carried
to term and delivered. Since all the embryos come from
the same zygote, they are genetically identical.
Somatic cell nuclear transfer (SCNT) involves the isolation
of a somatic (body) cell, which is any cell other then those
used for reproduction (sperm and egg, known as the germ
cells). In mammals, every somatic cell has two complete
sets of chromosomes, whereas the germ cells have only
one complete set. To make Dolly, scientists transferred the
nucleus of a somatic cell taken from an adult female sheep
and transferred it to an egg cell from which the nucleus had
been removed. After some chemical manipulation, the egg
cell, with the new nucleus, behaved like a freshly fertilized
zygote. It developed into an embryo, which was implanted
into a surrogate mother and carried to term.
Protein Engineering
Protein engineering technology is used, often in
conjunction with recombinant DNA techniques, to
improve existing proteins, such as enzymes, antibodies
and cell receptors, and to create proteins not found in
nature. These proteins may be used in drug development,
food processing and industrial manufacturing.
The most pervasive uses of protein engineering to date
are applications that alter the catalytic properties of
enzymes to develop ecologically sustainable industrial
processes. Enzymes are environmentally superior to
most other catalysts used in industrial manufacturing
because, as biocatalysts, they dissolve in water and work
best at neutral pH and comparatively low temperatures.
In addition, because biocatalysts are more specific than
chemical catalysts, they also produce fewer unwanted
byproducts. The chemical, textile, pharmaceutical, pulp
and paper, food and feed, and energy industries are all
benefiting from cleaner, more energy-efficient production
made possible by incorporating biocatalysts into
their production processes.
The characteristics that make biocatalysts environmentally
advantageous may, however, limit their usefulness in certain
industrial processes. For example, most enzymes fall apart
at high temperatures. Scientists are circumventing these
limitations by using protein engineering to increase enzyme
stability under harsh manufacturing conditions.
In addition to industrial applications, medical researchers
have used protein engineering to design novel
proteins that can bind to and deactivate viruses and tumor-causing
genes; create especially effective vaccines;
and study the membrane receptor proteins that are so
often the targets of pharmaceutical compounds. Food
scientists are using protein engineering to improve the
functionality of plant storage proteins and develop new
proteins as gelling agents.
In addition, new proteins are being developed to respond
to chemical and biological attacks. For example, hydrolases
detoxify a variety of nerve agents as well as commonly
used pesticides. Enzymes are safe to produce, store and
use, making them an effective and sustainable approach
to toxic materials decontamination.
Biosensors
B
iosensor technology couples our knowledge of biology
with advances in microelectronics. A biosensor
is composed of a biological component, such as a cell,
enzyme or antibody, linked to a tiny transducer—a device
powered by one system that then supplies power (usually
in another form) to a second system. Biosensors are
detecting devices that rely on the specificity of cells and
molecules to identify and measure substances at extremely
low concentrations.
Biotechnology Industry Organization n Guide to Biotechnology