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There's a Fruit in my Bug
An unprecedented finding has further tangled the complex web of parasite-host interactions: a parasitic worm that lays hundreds of eggs in an ant's abdomen, turning it bright red to create the appearance of a ripe berry. Robert Dudley of the Department of Integrative Biology and colleagues hypothesized that this dramatic color change fools ordinarily ant-averse birds into thinking they are eating a juicy red berry. Why such an elaborate scheme? Due to a meshwork that prevents the parasites from entering the ant's digestive tract, worm eggs cannot infect an adult ant when eaten. Instead, they must be consumed by the ant larvae as they are fed bird droppings by their foraging parents. Once ingested by the larvae, the worms can hatch and grow, migrate into the ant's abdomen, mate, and lay eggs, turning the abdomen red to hoodwink the next unsuspecting bird. To test the theory that birds are more likely to nosh on an infected ant, the research group secured healthy and infected ants side by side on branches in the forests of Panama and Peru. They found that the abdomen of the unlucky infected ant was more likely to disappear—presumably into the stomach of a bird—than that of its healthy counterpart. To further explore the birds' color preference, the scientists arranged differently colored clay balls along a branch and checked them daily for signs of a bird attack. They found more beak marks on the pink and red balls than on the rest of the colored balls combined, confirming that birds are attracted to berry colors. As further evidence of birds' role in mediating the parasite life-cycle, the research group showed that the droppings of chickens that had eaten infected ants were laden with worm eggs. Says Dudley, "It's the first documented case of trans-kingdom mimicry: a parasite inducing a morphological change in its animal host to make it look like fruit."
—Jasmine McCammon

Caught in Translation
For the last six years, three UC labs have been working together to accomplish a seemingly impossible feat—watching a single ribosome as it translates an RNA molecule into a functional protein. The results of this heroic collaboration between the labs of professors Carlos Bustamante and Ignacio Tinoco here at UC Berkeley and UC Santa Cruz professor Harry Noller were published last spring in the journal Nature. The researchers used optical tweezers, which are focused lasers used to hold macromolecules like protein and DNA, to measure the nano-scale motions of these molecules. The optical tweezers were used to monitor a single ribosome, a protein complex 20 nanometers in diameter, as it moved along a specially designed RNA fragment. The team was able to measure the ribosome moving three bases at a time, a distance corresponding to the stretch of RNA that encodes one amino acid of a protein. Essentially, the researchers were observing the ribosome "read" the genetic code in real time. Strangely, the ribosome's movement was occasionally interrupted by pauses lasting up to minutes. While the authors offer some potential causes for these prolonged delays, the mechanistic details remain a subject for future study. "What this paper really shows is that it's possible to get a system as complicated as the ribosome working in the optical tweezers set-up," says biophysics graduate student and co-author Courtney Hodges. "It also gives us something to explore for the next ten years."
—Katie Hart

Beams Away
Nuclear energy is often touted as a low-carbon method of electricity production. Yet nuclear fission, the process that powers today's nuclear plants, is not without its drawbacks. Researchers at LBL's Heavy-Ion Fusion Virtual National Laboratory are researching an alternative type of nuclear power—nuclear fusion. This process, which powers the sun and other stars, generates tremendous amounts of energy by combining small atoms, usually hydrogen, to form heavier elements such as helium. Fusion uses the readily available hydrogen isotopes deuterium and tritium as the fuel and doesn't generate greenhouse gases or large amounts of radioactive waste, unlike conventional power sources. However, extremely high temperatures are needed for fusion to occur, and the development of efficient and economical systems to generate such conditions is a huge challenge. To address this problem, Heavy Ion Fusion Program Director B. Grant Logan and his colleagues are investigating inertial confinement fusion, a technique that uses high-powered beams of charged particles (plasma) to induce fusion. By intensely focusing and compressing the beams, the researchers are able to create the high temperatures necessary for fusion to occur. The team has made breakthroughs in beam compression and is now able to focus the beams to deliver 700 times more than the initial beam energy. "With further improvements," says Logan, "we expect to increase compression to over 10,000 in the next few years, and we are assessing how these techniques apply to low cost fusion energy."
—Robin Padilla

Investing in Children
Can you give parents money to take better care of their children? That's the idea behind Conditional Cash Transfer (CCT) programs. These programs give low-income families money—up to 30 percent of the family's income—if they provide their children with regular medical check-ups, nutritional supplements, and meet certain school attendance requirements. In contrast to other similar programs, there are no restrictions on how CCT money can be spent. The hope was that the cash would be used on more nutritious food, a day off from work to take children to the doctor, or on school supplies, but families could also use it for rent or anything else they wish to purchase, including cigarettes or alcohol. Public Health professor Lia Fernald and colleagues recently investigated the effects of these programs in Mexico. The researchers showed for the first time that the amount of cash received by families is associated with improvements in cognitive, motor, and language development in young children. Families receive different amounts of money based on family size and the length of time they have been enrolled in the program. Fernald's group exploited these differences and used statistical methods to determine the effect that the quantity of cash had on a child's health and mental skills. Doubling the amount of money received resulted in increased height for age, lower average body mass index (BMI), and improved performance on cognitive, motor development, and language tests. Mexico's CCT program served as the model for programs now in place in over 20 countries, including one launched last year in New York City.
—Orapim Tulyathan

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