[PLoS One | 6.25.08]
Droughts and floods caused by global warming can create ideal conditions for infectious disease outbreaks that cause mass die-offs of livestock or wildlife, according to a study by an international team of scientists, including Craig Packer, Distinguished McKnight University Professor of Ecology, Evolution and Behavior.
Extreme climatic conditions are capable of altering normal host-pathogen relationships and causing a “perfect storm” of multiple infectious outbreaks that can trigger epidemics with catastrophic mortality.
Led by scientists at the University of California, Davis, the University of Illinois and the University of Minnesota, the study examined outbreaks of canine distemper virus (CDV) in 1994 and 2001, which killed about a third of the lions in Tanzania’s Serengeti National Park and Ngorongoro Crater. The virus periodically strikes these ecosystems, but most epidemics have caused little or no harm to the lions.
Both outbreaks were preceded by severe droughts, which weakened Cape buffalo, a major prey of lions, and left them heavily infested with ticks. Lions acquired high levels of tick-borne blood parasites from the buffalo. CDV suppressed the lions’ immunity, raising blood levels of parasites to deadly levels.
The lion populations recovered within three to four years after each event, but most climate change models predict increasing frequency of droughts in East Africa.
[Nature | 5.22.08]
Proteasomes are biological disposals that capture unneeded proteins in cells, break them down and send them on their way. Until recently, no one knew exactly how they worked. But Kylie Walters and colleagues solved part of the mystery in two research studies published in Nature. Walters is an associate professor in the Department of Biochemistry, Molecular Biology and Biophysics.
The Walters lab defined a new proteasome subunit (Rpn13) that binds to proteins marked for destruction. The University of Minnesota’s cutting-edge nuclear magnetic resonance and supercomputer facilities allowed the researchers to visualize how Rpn13 binds protein substrates that are degraded by the proteasome.
Proteasome dysfunction leads to cancer and neurodegenerative diseases. The findings will enable researchers to address proteasome dysfunction in a more targeted way that avoids side effects of current proteasome inhibitors.
[PLoS Biology | 5.6.08]
Judith Berman led a study, published online in PLoS Biology, demonstrating that genetic recombination occurs during the mating cycle of Candida albicans. The study showed that this requires the activity of a protein necessary for meiotic recombination in other eukaryotes.
Berman is a Distinguished McKnight University Professor in the Department of Genetics, Cell Biology and Development. Research associate Anja Forche also contributed to the study.
The opportunistic pathogen Candida albicans has a cryptic parasexual mating cycle involving epigenetic switching and chromosome loss suggesting potential advantages of a parasexual cycle over a conventional sexual cycle.
The National Institutes of Health has awarded Berman more than $2 million over five years to study centromere structure and function in Candida albicans. The work was motivated by the discovery of a centromeric region involved in chromosome rearrangements in drug-resistant isolates of this pathogenic yeast.
George Weiblen, associate professor of plant biology, has received a $400,000 grant from the National Science Foundation to establish a study in Papua New Guinea. The effort will be part of a global network to determine how these forests maintain their biodiversity over time and to estimate how much carbon they remove from the atmosphere.
Weiblen and colleagues will survey a 125-acre plot located in Wanang. Every tree will be mapped, tagged and identified. Trees will be measured every five years. Insects such as termites, moths, butterflies, ants and bees will also be inventoried. A lot of the work will be carried out by local scientists and villagers. The plot will be part of a global network representing 18 forests worldwide established by the Center for Tropical Forest Science, which is part of the Smithsonian Tropical Research Institute.
[Nature Cell Biology | 8.1.08]
Doctoral candidate Pankuri Goraksha-Hicks, advised by Thomas Neufeld, associate professor of genetics, cell biology and development, is lead author of a paper published in Nature Cell Biology. One of her figures from the paper was chosen as the cover image.
The paper reports findings about how cells sense nutrient levels in their environment. While it’s well known that cells control their rate of growth and metabolism according to the abundance of nutrients such as glucose and amino acids, and that the activity of a protein kinase called TOR is a key regulator of these processes, how changes in nutrient levels lead to changes in TOR activity has been a mystery.
The researchers identified a family of proteins, the Rag GTPases, as important components of the signaling pathway upstream of TOR. Dysregulation of TOR signaling has been implicated in a variety of human diseases including cancer, cardiovascular diseases, diabetes and neurodegeneration.
Faculty in CBS departments published 40 papers over the past five years (2003–08) in leading peer-reviewed scientific journals Science and Nature. That’s more than a third of the 117 papers published by University of Minnesota faculty in those journals over that time, and more than any other college.
[Proceedings of the National Academy of Sciences | 6.24.08]
Eric Hendrickson and colleagues in the Department of Biochemistry, Molecular Biology and Biophysics have discovered that reducing a protein (NHEJ) in human cells makes gene targeting much more effective. Accurate targeting is essential for removing or replacing defective genes. Their finding has important implications for using gene therapy to treat human diseases and modify the human genome. The publication was noted in the “Research Highlights” section of the July issue of Nature Structural Molecular Biology.
[Current Biology | 5.08]
David Greenstein and colleagues have discovered that a homolog of a gene involved in signaling oocyte (egg) maturation is also involved in ALS (Lou Gehrig’s Disease). Greenstein studied the protein in C. elegans, a worm used as a model organism. When the protein is absent in worms, eggs don’t mature. When the protein is mutated in humans, ALS develops. Greenstein, who joined the CBS faculty two years ago, studied C. elegans at Vanderbilt and Rockefeller universities for a decade before coming to the University of Minnesota. His finding yields an example of how basic science in a genetic model system provides unexpected insights into human health.
[International Journal of Primatology | 8.08]
Aggression among male chimpanzees is much more common than among females because it determines access to fertile females. But intense female fighting can occur when it has the potential to permanently change the females’ access to food resources and safety.
This new study by Anne Pusey and colleagues documents five cases of severe female aggression related to competition for space in Gombe National Park, Tanzania, where the quality of the core area occupied by a female is directly related to her reproductive success.
Pusey and colleagues also published articles in the May and June issues of the American Journal of Primatology. The first reported that illness (58%) and aggression (20%) were top causes of chimpanzee deaths. The second showed that the presence of researchers and tourists in Gombe exposes chimpanzees to human diseases, but protects them from hunters and loss of habitat. Michael L. Wilson was a co-author on all three papers and Jane Goodall a co-author on two. Pusey is a Distinguished McKnight Professor in the Department of Ecology, Evolution and Behavior.
