A.
Alcoholism and Drinking Capacity
Narrator:
This is Science Today. Children of alcoholics are
four times more likely than other people to become
alcoholics themselves. Psychiatrist Mark Schuckit
of the University of California, San Diego wondered
exactly what's inherited that might encourage alcoholism.
His alcoholic patients told him that as youngsters,
drinking didn't affect them much.
Schuckit: That early in their drinking
careers, like when they were in their early teens
or mid-teens or late teens, most people who went
on to develop alcoholism were telling me, gee, they
were really proud of how much alcohol they could
consume, and how they could drink everybody else
under the table.
Narrator: Schuckit tested 220 sons
of alcoholics against 220 sons of non-alcoholics
to see how sensitive they were to alcohol.
Schuckit: And we found that about
40 percent of the sons of alcoholics showed very
low levels of response to alcohol. And the same
was true for perhaps 5 to 10 percent of the sons
of non-alcoholics.
Narrator: And ten years later,
sons of alcoholics who weren't sensitive to alcohol
were four times more likely to become alcoholics
themselves. For Science Today, I'm Steve Tokar.
B.
The David and Goliath of the Insect World
Narrator:
This is Science Today. The tobacco hornworm, a major
agricultural pest, is an insect Goliath -- a fat
bug three inches long.
Beckage: Because these are very
large caterpillars, a single caterpillar can destroy
many tomato leaves within a single day due to their
large size. They're like eating machines.
Narrator: Entomologist Nancy Beckage
of the University of California, Riverside is studying
the David that brings the hornworm down -- a tiny
parasitic wasp that injects its eggs into the caterpillar.
The eggs hatch and the larvae feed on the caterpillar
from within, killing it.
Beckage: How this happens is that
many parasites are injected into a single host.
So in this case it's called a gregarious parasite,
meaning that it likes to have its buddies along,
and so we have several hundred parasites developing
within a single host.
Narrator: In the process, the caterpillar
stops eating. Beckage is studying how and why, in
hopes that the wasp will offer a natural, pesticide-free
method for controlling a major pest. For Science
Today, I'm Steve Tokar.
C.
Putting Evolution to the Test
Narrator:
This is Science Today. About 300 million
years ago, there was one and a half times more oxygen
in the atmosphere than there is now. The thick rich
air permitted the evolution of dragonflies the size
of seagulls. Twenty or 30 million years later, in
what scientists call the Permian period, the oxygen
level plummeted and the huge insects went extinct.
Biologist Jeff Graham of the University of California,
San Diego says that's no coincidence.
Graham: If you think about an animal
that might have evolved because of the presence
of large quantities of oxygen in the atmosphere,
well, if you pull that oxygen out of the atmosphere,
the effect might well have been to drive them to
extinction.
Narrator: You can't go back and
prove that theory, but Graham says you can test
it. Breed insects at, say, ten thousand feet, where
the air is thinner.
Graham: And there one can effect
-- naturally -- changes in the atmospheric oxygen
which would have been very analogous to the kinds
of conditions that were coming on in the Permian
with respect to atmospheric oxygen levels.
Narrator: If generations of insects
change size in proportion to oxygen, it would provide
a brief glimpse of how evolution works over millions
of years. For Science Today, I'm Steve Tokar.
D.
Drug Designers
Track A Moving Target
Narrator:
This is Science Today. More and more drugs are being
designed on computer. In rational drug design, as
it's called, scientists design a drug molecule that
binds to a specific site on a virus or bacteria,
like a key in a lock, blocking the action of the
disease. Biochemist Andrew McAmmon of the University
of California, San Diego says the design process
doesn't stop there.
McAmmon: One of the great virtues
of rational drug design is that it may create a
relatively effective way of responding to the appearance
of resistant emergent strains of viruses or bacteria.
Narrator: When a virus or bacteria
becomes resistant, what's happened is that the target
area has changed size, so the drug molecule no longer
fits. But rational drug designers can go to their
computers and design a new drug that fits the mutated
disease.
McAmmon: I think the whole nature
of the pharmaceutical business in the 21st century
is going rely very heavily on computers to track
these moving targets and to re-engineer drugs to
respond to the emergence of resistant strains.
Narrator: For Science Today, I'm
Steve Tokar.
E.
Why First-Time
Mothers Feel Guilty
Narrator:
This is Science Today. Psychologist Robin DiMatteo
of the University of California, Riverside did a
study of women who'd recently given birth for the
first time. She found that many of them weren't
prepared for their own emotional reactions .
DiMatteo: I think that the media
often present, particularly in fictional TV shows,
a mother who has just given birth and suddenly is
as happy as can be, is deeply in love with her baby
and maybe even looks great too.
Narrator: But as DiMatteo points
out, it isn't called "labor" for nothing.
DiMatteo: Thirty or forty hours
of labor is an incredible amount of work, and they
were absolutely exhausted by the time the baby was
born. They needed to be taken care of as well. And
almost everyone that talked about it felt guilty.
Narrator: That is, until they talked
to other mothers who felt the same way.
DiMatteo: That makes a lot of sense,
you don't really feel like taking on a new responsibility
after you've just run a marathon. You want to rest.
Narrator: For Science Today, I'm
Steve Tokar.
