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Archive - Sep 3, 2013

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Blind Mole-Rats Resistant to Chemically-Induced Cancers

Like naked mole-rats (Heterocephalus gaber), blind mole-rats (of the genus Spalax) live underground in low-oxygen environments, are long-lived, and resistant to cancer. A new study demonstrates just how cancer-resistant Spalax are, and suggests that the adaptations that help these rodents survive in low-oxygen environments also play a role in their longevity and cancer resistance. The findings were reported online on August 9, 2013 in an open-access article in the journal Biomed Central: Biology. "We've shown that, compared to mice and rats, blind mole-rats are highly resistant to carcinogens," said Dr. Mark Band, the director of functional genomics at the University of Illinois Biotechnology Center and a co-author on the study. Dr. Band led a previous analysis of gene expression in blind mole-rats living in low-oxygen (hypoxic) environments. He found that genes that respond to hypoxia are known to also play a role in aging and in suppressing or promoting cancer. "We think that these three phenomena are tied in together: the hypoxia tolerance, the longevity, and cancer resistance," Dr. Band said. "We think all result from evolutionary adaptations to a stressful environment." Unlike the naked mole-rat, which lives in colonies in Eastern Africa, the blind mole-rat is a solitary rodent found in the Eastern Mediterranean. Thousands of blind mole-rats have been captured and studied for more than 50 years at Israel's University of Haifa, where the animal work was conducted. The Haifa scientists observed that none of their blind mole-rats had ever developed cancer, even though Spalax can live more than 20 years. Lab mice and rats have a maximum lifespan of about 3.5 years and yet regularly develop spontaneous cancers. To test the blind mole-rats' cancer resistance, the Haifa team, led by Dr. Irena Manov, Dr. Aaron Avivi, and Dr.

Bird Odor Predicts Reproductive Success

For most animals, scent is the instant messenger of choice for quickly exchanging personal profiles. Scientists, however, have long dismissed birds as odor-eschewing Luddites that don’t take advantage of scent-based communications. In a first-of-its-kind study, however, a Michigan State University researcher has demonstrated that birds do indeed communicate via scents, and that odor reliably predicts their reproductive success. The study was published online on August 29, 2013 in Animal Behaviour and focuses on volatile compounds in avian preen secretions. Birds’ preen glands are located near their tails. Using their beaks, birds extract oil from the glands and rub it on their feathers and legs. Historically, this activity was thought to simply bolster the strength of feathers. Dr. Danielle Whittaker, managing director of MSU’s BEACON Center for the Study of Evolution in Action, and her research team, however, have shown that it plays a key role in signaling reproductive health. “This study shows a strong connection between the way birds smell near the beginning of the breeding season – when birds are choosing mates – and their reproductive success for the entire season,” she said. “Simply put, males that smell more ‘male-like’ and females that smell more ‘female-like’ have higher genetic reproductive success.” The long-held assumption was that birds’ preferred methods of communication and mate selection were visual and acoustic cues. Studying dark-eyed juncos (see image courtesy of Nicole Gerlach), Dr. Whittaker’s team compared which were more effective – chemical signals or size and attractive plumage. The results showed that individual bird odor correlated with reproduction success while size and plumage were less reliable.

New Method for Turning Genes On and Off Could Enable More Complex Synthetic Biology Circuits

MIT researchers have shown that they can turn genes on or off inside yeast and human cells by controlling when DNA is copied into messenger RNA — an advance that could allow scientists to better understand the function of those genes. The technique could also make it easier to engineer cells that can monitor their environment, produce a drug, or detect disease, says Dr. Timothy Lu, an assistant professor of electrical engineering and computer science and biological engineering and the senior author of a paper describing the new approach that was published online on August 26, 2013 in the journal ACS Synthetic Biology. “I think it’s going to make it a lot easier to build synthetic circuits,” says Dr. Lu, a member of MIT’s Synthetic Biology Center. “It should increase the scale and the speed at which we can build a variety of synthetic circuits in yeast cells and mammalian cells.” The new method is based on a system of viral proteins that has been exploited recently to edit the genomes of bacterial and human cells. The original system, called CRISPR, consists of two components: a protein that binds to and slices DNA, and a short strand of RNA that guides the protein to the right location on the genome. “The CRISPR system is quite powerful in that it can be targeted to different DNA binding regions based on simple recoding of these guide RNAs,” Dr. Lu says. “By simply reprogramming the RNA sequence you can direct this protein to any location you want on the genome or on a synthetic circuit.” Lead author of the paper is Fahim Farzadfard, an MIT graduate student in biology. Samuel Perli, an MIT graduate student in electrical engineering and computer science, is also an author. In previous studies, CRISPR has been used to snip out pieces of a gene to disable it or replace it with a new gene. Dr.