Life & Non-humans

Global Warming, Climate Changes May Make Mass Extinction Unavoidable

Worldwide efforts to protect plant and animal species may not be enough to avoid a mass extinction in the face of unexpected climate changes and global warming, says an international team of researchers. While the Earth’s climate is never stable, natural records of the past — such as fossils, ice cores, corals, and lake sediments — reveal that the species and ecosystems of today evolved within a specific range of climate conditions. The scientists are concerned that human activities, such as increased carbon dioxide emissions into the atmosphere, may push the climate outside of its current range, with devastating impacts on species around the globe.

Study first to show how tuberculosis moves through the body

A University of Washington study is the first to provide visualizations of tuberculosis infections in an intact living organism and reveals how tuberculous granulomas, the tight aggregates of macrophages that are the hallmarks of this infection, are formed within infected organisms (Macrophages are a specialized class of white blood cells that patrol tissues and ingest foreign particles, such as bacteria and viruses, as well as dead and dying cells. Macrophages provide the backbone of the immune system.)

U.S. Carcinogens Report Lists Estrogen Therapy, Ultraviolet, Wood Dust

The federal government today published its biennial Report on Carcinogens, adding steroidal estrogens used in estrogen replacement therapy and oral contraceptives to its official list of “known” human carcinogens. This and 15 other new listings bring the total of substances in the report, “known” or “reasonably anticipated” to pose a cancer risk, to 228. Among the other new additions: wood dust and ultraviolet light.

Increasing biodiversity is not always best

Biodiversity worldwide may be decreasing, but at smaller scales it is increasing or at least changing in composition, suggesting the need for a dramatic shift in the current focus of ecological research. These changes may undermine the functioning of local ecosystems, according to an article in December’s American Naturalist. The authors studied data collected on oceanic island land birds and plants. Records from islands are useful because they present discrete areas where additions and subtractions of species can be accurately determined. The article, “Species Invasions Exceed extinctions on Islands Worldwide: A Comparative Study of Plants and Birds,” documents the fact that “land birds have experienced massive extinctions on oceanic islands, with many islands losing more than half of their native species,” said Gaines. “On these same islands, however, many exotic bird species have become established, such that the total number of land bird species has remained relatively unchanged.”

Gene Identified for Obesity, Physical Activity, Sex Behaviors in Mice

A team led by University of Massachusetts Amherst researcher Deborah J. Good has identified a gene that appears to play a role in obesity, physical activity, and sex behaviors in mice. Good works with so-called “knock-out” mice, which have a specific gene deleted. Scientists then monitor the animals for changes in their physiology and behavior, in an effort to determine the gene’s role. Her findings are detailed in the current issue of the journal Physiology and Behavior. The project is funded with a four-year, $1 million grant from the National Institute of Diabetes and Digestive and Kidney Diseases, and a two-year, $70,000 grant from the National Institute of Child Health and Human Development, both of the National Institutes of Health.

Coral Layers Good Proxy for Atlantic Climate Cycles

Tree rings may tell how old a tree is, but the rings or annual bands in some skeletal coral may tell not only the age of the animal, but also something of the dynamics of the ocean in which it grew, according to Penn State and University of Miami researchers. “Some coral grows like a tree; each year a complete layer with both a high and low-density skeletal calcium carbonate band is formed by the coral animal,” says Dr. Lisa Greer, assistant professor of geosciences. “Not all corals create rings, but the massive corals like boulder star coral or pin cushion coral do.”

Researchers decipher optical spectra of carbon nanotubes

Building upon this summer’s groundbreaking finding that carbon nanotubes are fluorescent, chemists at Rice University have precisely identified the optical signatures of 33 “species” of nanotubes, establishing a new methodology for assaying nanotubes that is simpler and faster than existing methods. In research published this week by Science magazine, a spectroscopy research team led by Rice Chemistry Professor R. Bruce Weisman detailed the wavelengths of light that are absorbed and emitted by each type of light-emitting nanotube. The findings hold great promise for chemists, physicists and materials scientists studying nanotubes, because it otherwise takes many hours of tedious testing for researchers to assay a single sample of nanotubes, and optical tests could be much faster and simpler.

Lichens surprisingly precise air quality monitors

Lichens, combinations of fungi and algae, are quietly trodden underfoot by animals and hikers the world over. Now a new study by a Brigham Young University father-son team has demonstrated that lichens could replace expensive environmental monitors since they accumulate some pollutants in concentrations that correctly manifest the amount of the pollutants in the surrounding air. “Previously, we knew that lichens took things up from the air, but no one had any significant results indicating that what is in the lichen accurately reflects what is in the air,” said Larry St. Clair, the chair of BYU’s department of integrative biology and co-author of the study published in the latest issue of “Atmospheric Environment.” “This is the first definitive data that shows not only do lichens take pollution up from the air, but they take it up in patterns that exactly reflect the amount of pollutants in the air.”

Fossil fuels for cooking, heating may be best for world’s 2 billion poor

Contrary to conventional wisdom, the use of fossil fuels for household cooking and heating may make more environmental sense for the estimated 2 billion rural poor in the world, according to a researcher from the University of California, Berkeley. Because they contribute to greenhouse gas emissions, fossil fuels have been largely dismissed as a viable alternative for the one-third of the world’s population who now use coal and local biomass – including wood, crop residues and dung – for cooking and heating, said Kirk R. Smith, professor and chair of environmental health sciences at UC Berkeley’s School of Public Health. Efforts have been focused on equipping the rural poor with renewable energy sources, such as solar and wind power.

Bread as cause of acne?

Forget about chocolate and greasy foods. Eating too much refined bread and cereal may be the true culprit behind the pimples that plague many a youngster, reports Britain’s New Scientist magazine. That’s the theory of a team led by Loren Cordain, an evolutionary biologist at Colorado State University in Fort Collins. Highly processed breads and cereals are easily digested. The resulting flood of sugars makes the body produce high levels of insulin and insulin-like growth factor (IGF-1). This in turn leads to an excess of male hormones. These encourage pores in the skin to ooze large amounts of sebum, the greasy goop that acne-promoting bacteria love. IGF-1 also encourages skin cells called keratinocytes to multiply, a hallmark of acne, the team say in a paper that will appear in the December issue of Archives of Dermatology.

The Mouse Genome And The Measure of Man

The international Mouse Genome Sequencing Consortium today announced the publication of a high-quality draft sequence of the mouse genome – the genetic blueprint of a mouse – together with a comparative analysis of the mouse and human genomes describing insights gleaned from the two sequences. The paper appears in the Dec. 5 issue of the journal Nature. The achievement represents a landmark advance for the Human Genome Project. It is the first time that scientists have compared and contrasted the contents of the human genome with that of another mammal. This milestone is all the more significant given that the laboratory mouse is the most important animal model and is widely used in the study of human diseases.

Even in fish, one parent does more

Like bickering spouses in an underwater episode of “Dr. Phil,” parents in the fish world want their mates to take more responsibility for child-rearing – so they can do less, says CSUS biological sciences professor Ronald Coleman. In convict cichlids, for example, Coleman finds that while parenting duties are shared, they’re not shared equally. “Both hope the other will do the work,” he says. Convict cichlids are good parents who defend their children, Coleman says. But individual pairs vary in determining how much each parent should do for their offspring.

Beer, yeast offer new insight into evolution

Researchers studying yeast reproductive habits have for the first time observed a rapid method for the creation of new species, shedding light on the way organisms evolve. “Most models of speciation require gradual change over a very long period of time, and geographic or ecological isolation for a new species to arise,” says University of Houston biologist Michael Travisano. “Our study suggests that mating two separate species to produce hybrids can result in a new species readily and relatively quickly, at least in yeast, but possibly in other organisms as well.”