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Research Roundup

17 July 2008

Genes could solve pollution mysteries

Berkeley researchers have for the first time identified environmental pollutants by looking at the genes of a small, freshwater crustacean. This new gene-based technique could lead to better and faster lab tests for pinpointing pollutants in contaminated ecosystems.

Scientists measured changes in gene expression in the genome of Daphnia magna, the tiny, transparent water flea commonly used for lab studies, to track down poisons in two polluted rivers in California. This is the first time gene expression has been used to identify an environmental pollutant — in this case, copper from nearby mines.

The genomic technique has the potential to be faster, cheaper, and more informative than current water-toxicity assays, says the study’s senior author, Chris Vulpe, associate professor of nutritional sciences and toxicology.

Parasite vaccines within reach

Even though parasites are complex creatures, the mammalian immune response to them is surprisingly simple, leading Berkeley researchers to predict that creating vaccines for parasitic diseases such as malaria may be more straightforward than initially thought.

The researchers found that the mammalian immune system responds to just one protein in Toxoplasma gondii, the single-celled parasite that causes toxoplasmosis and encephalitis, even though Toxoplasma has approximately 8,000 different proteins. Healthy people generally have nothing to fear from Toxoplasma, but it can be dangerous for babies or for AIDS patients and other people with depressed immune systems.

In the study, published online in the journal Nature Immunology, immunologist Nilabh Shastri and his colleagues identified the unique Toxoplasma protein involved in the mouse immune response and generated the first successful Toxoplasma vaccine.

This finding could have important implications for other parasitic diseases, says lead author Shastri. If our bodies respond to similar parasites such as malaria in the same way, finding vaccines for these parasites may be more feasible than originally thought, he notes.

Climate change could affect California’s native plants

The native plants unique to California are so vulnerable to global climate change that two-thirds of these “endemics” could suffer more than an 80 percent reduction in geographic range by the end of the century, according to a new Berkeley study.

Because endemic species make up nearly half of all California’s native plants, a changing climate will have a major impact on the state’s unparalleled plant diversity, the researchers warn.

“The magnitude and speed of climate change today is greater than during past glacial periods, and plants are in danger of getting killed off before they can adjust their distributions to keep pace,” says David Ackerly, professor of integrative biology.

The researchers project that, in response to rising temperatures and altered rainfall, many plants could move northward and toward the coast, following the shifts in their preferred climate, while others, primarily in the southern part of the state and in Baja California, may move up mountains into cool but highly vulnerable “climate-change refugia.” They argue that it’s not too early to prepare for this eventuality by protecting corridors through which plants can move to such refugia, and maybe even assisting plants in re-establishing themselves in new regions.

“Part of me can’t believe that California’s flora will collapse over a period of 100 years,” says Ackerly. “We haven’t seen such drastic changes in the last 200 years of human history, since we have been cataloguing species.”