A. Pro-Inflammatory Protein Contributes to Crohn's Disease
Narrator: This is Science Today. A pro-inflammatory protein has been found to contribute to Crohn's Disease, a chronic inflammatory bowel disease that affects more than half a million Americans and is considered a high risk factor for colon cancer. Michael Karin, a professor of pharmacology at the University of California, San Diego led the study.
Karin: What we do is introduce the same mutation that is present in the diseased gene in humans into the mouse gene and this is possible because the genes are very, very similar in human and mouse.
Narrator: Karin and his colleagues identified interleukin-1Beta, or il1-beta, as a major cause of severe inflammation in the mouse model of Crohn's Disease.
Narrator: So that led us to consider that maybe il-1beta plays a very important role in the pathogenesis of this inflammatory response that we see in the mice. So we think that il-1 beta needs to be examined as maybe an important mediator of Crohn's Disease in human patients.
Narrator: For Science Today, I'm Larissa Branin.
B. New Insight into the Body's Regulation of Energy Balance
Narrator: This is Science Today. The main function of the region of the brain called the hypothalamus is homeostasis – the regulation of the body's status quo, including food intake and body weight. Christian Vaisse, an assistant professor of medicine at the University of California, San Francisco, is studying a brain protein expressed in the hypothalamus called the melanocortin-4 receptor, which is already known to play a role in the urge to eat.
Vaisse: In 1998, we actually described the first mutation in the melanocortin 4 receptor in humans and it turns out about 2.5 percent of all severely obese humans have mutations in the melanocortin-4 receptors.
Narrator: Recently, Vaisse discovered a new group of mutations in this receptor that affects the body's baseline level of activity.
Vaisse: This is a protein that is implicated in the long-term regulation of energy balance. So basically, what it helps do is adapt your energy intake, which is your food intake, to your energy expenditure.
Narrator: For Science Today, I'm Larissa Branin.
C.
Study May Help Policymakers Reduce Cost of Natural Gas
Narrator: This is Science Today. Ryan Wiser, a scientist at the Lawrence Berkeley National Laboratory recently shared his latest study with the US Senate on how renewable energy sources, like solar and wind power, could affect energy markets. With a new energy bill on the table, the findings of Wiser's study may help policymakers reduce the cost of natural gas.
Wiser: What they want to know from me effectively the results of the study and what that means for policy. What level of costs or natural gas price reduction might be seen if you increase renewable energy sources up to the level that they are contemplating in their policy actions, how does that compare with various supply side measures to reduce natural gas prices.
Narrator: Wiser says in the next two decades consumers may see significant increases in the use of renewable energy sources.
Wiser: On the table is a pretty aggressive national commitment to renewable energy such that renewable energy achieves anywhere from a 10-20 % share of US electricity supply over the next 20 years.
Narrator: For Science Today, I'm Larissa Branin.
D.
Challenging Consumer Assumptions about Organic Farming
Narrator: This is Science Today. A University of California study has found that, with the exception of reduced exposure to pesticides, the growth in organic agriculture has not resulted in better working conditions for farmworkers. This is contrary to some consumer assumptions that organic producers get more benefit from organic production than conventional agriculture. Another study, conducted by Julie Guthman, a community studies professor at the University of California, Santa Cruz, also challenged popular assumptions about organic farming.
Guthman: Even at its best, organic farming never looked like the imaginary that people impose on it because California never had a class of family farmers who grew for the market with their own family labor. I mean California agriculture has been based on migrant wage labor since we moved into specialty production – actually, before then in the 19 th Century. So, I think if we're concerned about ecological farming and social justice in farming, we need to create new imaginaries and not go back to a past that never was.
Narrator: For Science Today, I'm Larissa Branin.
E.
The Evolutionary Process of Adaptive Radiation
Narrator: This is Science Today. University of California, Berkeley biologist Rosemary Gillespie describes how Hawaiian spiders developed into multiple species from a single spider. By studying the DNA of these spiders, Gillespie noticed that as the spiders traveled between islands they used what is called adaptive radiation to change and take advantage of new food sources.
Gillespie: Adaptive radiation is basically where you get a single line or a single colonist arriving on an island and diversifying into multiple species that occupy different ecological roles.
Narrator While Adaptive radiation has occurred in Hawaii for centuries, Gillespie wonders if this process will continue.
Gillespie: What' we've done by having planes going to Hawaii by having boats going to Hawaii, with all this immigration we have basically put the islands very much closer to a source of migrants. What we have to think about is what is that going to do to the natural communities. How is that going to affect the way communities are assembled?
Narrator: For Science Today, I'm Larissa Branin.
