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Archive - Aug 30, 2012

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Bacteria in Hyena Scent Glands Key to Group-Specific Social Odors

The results, published online on August 30, 2012 in Scientific Reports, a Nature publication, show a clear relationship between the diversity of hyena clans and the distinct microbial communities that reside in their scent glands, said Dr. Kevin Theis, the paper’s lead author and a Michigan State University (MSU) postdoctoral researcher. “A critical component of every animal’s behavioral repertoire is an effective communication system,” said Dr. Theis, who co-authored the study with Dr. Kay Holekamp, an MSU zoologist. “It is possible that without their bacteria, many animals couldn’t ‘say’ much at all.” This is the first time that scientists have shown that different social groups of mammals possess different odor-producing bacterial communities. These communities produce unique chemical signatures, and the hyenas can distinguish among them by using their noses. Past research has demonstrated important roles played by microbes in digestion and other bodily functions. It’s also widely known that most mammals use scent to signal a wide range of traits, including sex, age, reproductive status, and group membership. This study details bacteria living in a mutually beneficial relationship with their hyena hosts. It also highlights the contribution of new DNA sequencing technologies showcasing the role good, symbiotic bacteria play in animal behavior. On the grassy Kenyan plains, Dr. Theis gathered information about the bacterial types present in samples of paste, a sour-smelling secretion that hyenas deposit on grass stalks. Field samples were collected from hyenas’ scent pouches and analyzed using next-generation sequence (NGS) technology back at MSU labs. The samples revealed a high degree of similarities, microbial speaking, between deposits left by members of the same clans.

Protein Linked to Increased Risk of Heart Failure/Death in Older Adults

A protein known as galectin-3 can identify people at higher risk of heart failure, according to new research supported by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. This research is based on work from the NHLBI's Framingham Heart Study, which began in 1948 and has been the leading source of research findings about heart disease risk factors. The article was published online on August 29, 2012 in the Journal of the American College of Cardiology and will also be published in the October 2, 2012 print issue of the same journal. Heart failure occurs when the heart cannot fill with enough blood and/or pump enough blood to meet the body's needs. Galectin-3 has recently been associated with cardiac fibrosis, a condition in which scar tissue replaces heart muscle, and cardiac fibrosis plays an important role in the development of heart failure. Heart failure carries enormous risk for death or a lifetime of disability and often there are few warning signs of impending heart failure. Measuring levels of galectin-3 in the blood may offer a way to identify high-risk individuals who could benefit from treatments to prevent debilitating heart failure and death. Early identification of predisposed individuals would allow treatment to begin long before heart failure develops and could help people at high risk for heart failure to live longer, more active lives. Galectin-3 levels were measured in 1996-1998 as part of a routine examination of 3,353 participants enrolled in the Offspring Cohort of the Framingham Heart Study. At the time of measurement, the average age of the participants was 59 years old. During an average follow-up of 11 years, 166 participants (5.1 percent) had a first heart failure event.

Max Planck Researchers Describe Ancient Denisovan Genome

The analyses of an international team of researchers led by Dr. Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, show that the genetic variation of Denisovans was extremely low, suggesting that although they were present in large parts of Asia, their population was never large for long periods of time. In addition, a comprehensive list documents the genetic changes that set modern humans apart from their archaic relatives. Some of these changes concern genes that are associated with brain function or nervous system development. In 2010, Dr. Pääbo and his colleagues sequenced DNA that they isolated from a finger bone fragment discovered in the Denisova Cave in southern Siberia. They found that it belonged to a young girl of a previously unknown group of archaic humans that they called “Denisovans.” Thanks to a novel technique which splits the DNA double helix so that each of its two strands can be used for sequencing, the team was able to sequence every position in the Denisovan genome about 30 times over. The thus-generated genome sequence shows a quality similar to genomes that have been determined from present-day humans. In a new study, which was published online on August 30, 2012 in Science, Dr. Pääbo and his colleagues compare the Denisovan genome with those of the Neandertals and eleven modern humans from around the world. Their findings confirm a previous study according to which modern populations from the islands of southeastern Asia share genes with the Denisovans.