Explore Biotech | Can you believe it?

Imagine an organism that can withstand severe
drought, frigid temperatures and lethal levels of
radiation. These are just a few of the properties of
Deinococcus radiodurans, a microbe listed in the
Guinness Book of World Records as "the world's
toughest bacterium." This microbe was first
identified in a can of meat that spoiled despite the
fact that it had been sterilized by radiation. Exposure
to high levels of radiation causes breaks to occur
within strands of DNA. Organisms rely on repair
enzymes to fix the breaks, but these repair
mechanisms have their limits. So what gives D.
radiodurans the ability to deal with huge doses of
radiation? The secret lies in the structure of its
genome. While other bacteria have only 1 copy of
their DNA, D. radiodurans has 4. Most importantly,
the DNA is packed in a tight ring, which prevents
the DNA pieces from floating off into other parts
of the cell. This allows the microbe to quickly and
accurately rebuild its DNA. Researchers hope to
use D. radiodurans to help clean-up
radioactively contaminated sites.

Scientists have been using plants to mop
up pollutants from soil for a while now.
However, this process, known as
phytoremediation, has been hindered by the
fact that few naturally occurring plants grow
well in polluted soils. To give Mother Nature a
little help with cleaning-up arsenic
contaminated soils, scientists have modified
thale cress plants (a small weed related to
mustard plants) to include 2 genes from
E. coli. The first gene enhances the plant's
natural ability to take up arsenate. The second
gene helps the plants bind more tightly to
arsenate, making this compound less bio-
available and thus less toxic to the plants.
The result is a plant that grows well in arsenic
polluted soils and which has the ability to
remove arsenic from the soil at a rate three
times faster than that of unmodified plants.
Once the arsenic has been concentrated in
the plants' tissues, the plants can be safely
incinerated. Down the road, researchers hope
to turn large trees into soil-cleaning machines.

We can learn a lot about science by cooking an egg.
For instance, you've probably noticed that egg whites
start off clear and colorless, but turn white when
cooked. This is because in their native state the
proteins in egg whites are completely dissolved in
fluid. Upon heating, the proteins become denatured
and unwind. New protein bonds eventually form,
producing a tighter more intricately connected mass.
The clusters of proteins now deflect light rays and
the egg whites appear opaque. When cooking eggs
it is best to use moderate heat since high heat
causes the eggs to become tough and rubbery. The
mechanical energy exerted by whisking causes a
similar effect in which protein bonds break and a
new network of cross-linking bonds form, allowing
the egg whites to form soft peaks.