Life & Non-humans

Slowest-evolving species gains upper hand

When members of two species compete directly with each other, scientists believe the one that rolls with the evolutionary punches and adapts most quickly has the upper hand. But new evidence suggests that in relationships that benefit both species, the one that evolves more slowly has the advantage. “The idea that has been dominant for the last couple of decades is that when two species co-evolve, they try to outrun each other,” said Carl Bergstrom, a University of Washington assistant zoology professor. But that doesn?t necessarily hold true for individuals of different species engaged in a mutualistic, or symbiotic, relationship. In such cases, he said, the one that evolves more slowly is likely to gain a disproportionate share of benefits from the relationship.

Surprises from Past Could Spell Longer Droughts, Rising Sea Levels

Abrupt climate changes could lead to decade-long droughts and massive sea-level rise, according to a University of Arizona geoscientist who studies the climate of the distant past. Factors that influence the climate system, such as natural changes in the Earth’s orbit or rising carbon dioxide emissions from cars and power plants, can result in dramatic climate shifts, says Jonathan Overpeck, a professor of geosciences and director of the UA Institute for the Study of Planet Earth. Scientists studying natural climate records, such as the variations in tree rings and gas bubbles trapped in the polar ice caps, find ample evidence of these types of rapid changes in the past — sometimes occurring in a decade or less.

An unlikely new weapon against deadly bacteria in oysers: A virus

People looking forward to eating raw oysters over the holidays will welcome news that scientists are making progress in the fight against a rare but deadly disease associated with the tasty bivalves. Two Florida researchers report curing mice of the disease by using a virus to attack its bacterial source – Vibrio vulnificus. The scientists say the research may lead to techniques to purify oysters after harvest but before they reach raw bars and seafood markets – and might one day result in a better cure for the disease in people. The work, reported in a November article in the journal Infection and Immunity, is part of a growing trend in research to use bacteria-attacking viruses, or “phages,” to cure diseases caused by bacteria.

Researchers explain how we detect the location of sound

The slightest turn of the head can significantly change the way a person or animal detects sound. A subtle tilt alters the angle at which high-frequency sound waves hit the ear, providing cues to localize the sound. To use those cues, the brain must put what it hears into the context of the position of the head. Until recently, scientists were not sure how this was done. Now researchers in Wisconsin appear to have the explanation. They have discovered that in the cochlear nucleus, the first sound-processing station in the brain, certain cells accomplish the job by integrating the two kinds of information, each of which travels along a distinct pathway.

Molting habits may have led to extinction of once-hardy trilobite

Molting, that periodic ritual in which arthropods shed and replace their outer skeletons, can be a dangerous time for the creatures. Just ask the trilobite. Research published by an MSU paleontologist suggests that an inconsistent molting style, coupled with inefficient physiology, contributed to the demise of these prehistoric relatives of today’s crabs and lobsters nearly 250 million years ago.

Ultrasound chemotherapy could cut side-effects, improve treatment

Cancer patients undergoing chemotherapy often endure painful side effects caused by the powerful drugs as they course through their entire bodies, damaging healthy tissue and tumors alike. Utah researchers are reporting in the December issue “Cancer Research” that they have successfully tested a new method in laboratory animals that would concentrate the impact of cancer drugs on specific cancerous tissues, thus sparing the rest of the body from harm.

Researchers turn rat stem cells into mouse marrow cells

Researchers in North Carolina have successfully demonstrated that genetically altered stem cells from one species can be turned into a different sort of cell in another. Specifically, the researchers converted adult liver stem cells cloned from a male rat into functional adult bone marrow cells in female mice. The accomplishment, known as hematopoietic transdifferentiation, may prove useful for tapping the potential for tissue repair using human adult stem cells.

Microorganisms isolated in space

Indian and British researchers say they have successfully isolated microorganisms living in the upper atmosphere, as high as 40 km up. Whether the organisms originate on Earth or are “seeding” the planet from passing comets is the subject of some debate. “Contamination is always a possibility in such studies but the ‘internal logic’ of the findings points strongly to the organisms being isolated in space, at a height of 41km,” said one of the lead researchers. “Of course the results would have been more readily accepted and lauded by critics had we isolated novel organisms, or ones with NASA written on them! “

Enzymes Could Help Fight Drug-Resistant Bacteria

Researchers at Harvard say they have overcome a preliminary, yet critical, hurdle in the push to develop antibiotics against drug-resistant bacterial strains. Most attempts have been plagued by a lack of molecular tools for manipulating–and ultimately improving — the structure of naturally occurring antibiotics. The researchers report that they harnessed two enzymes, which work by adding sugars to a central molecular core, and used them to create new versions of two potent antibiotics, vancomycin and teicoplanin.

New gene therapy boosts immune system to cure cancer in mice

Using a novel gene therapy approach that boosts the body?s immune system, a researcher has cured cancer in laboratory mice. In experiments reported in the Dec. 15 issue of Cancer Research, Chung Lee and colleagues at the Feinberg School of Medicine at Northwestern University applied the gene therapy technique to render immune cells insensitive to transforming growth factor beta (TGF-beta), a powerful, naturally occurring substance in the body called an immunosuppressor that enables cancer cells to evade surveillance by the immune system. The approach boosted the mice?s immune system, which virtually eliminated cancerous tumors in the animals’ lungs and prostate gland.

Ultrasound Shown To Be Potentially Safe, Effective Way to Kill Bacteria

High-power ultrasound, currently used for cell disruption, particle size reduction, welding and vaporization, has been shown to be 99.99 percent effective in killing bacterial spores after only 30 seconds of non-contact exposure in experiments. In the experiments, bacterial spores contained in a paper envelope, were placed slightly (3mm) above the active area of a specially equipped source of inaudible, high frequency (70 to 200 kHz) sound waves and hit for 30 seconds. There was no contact medium, such as water or gel, between the ultrasound source and the spores as is typically used in low-power, medical diagnostic ultrasound. The experiments mark the first time that Non-Contact Ultrasound (NCU) has been shown to inactivate bacterial spores.

Zebrafish May Point the Way to Mending a Broken Heart

Researchers have found that the secret to mending a broken heart — at least at the molecular level — resides within the two-chambered heart of a fish commonly found in household aquariums. The scientists showed that the zebrafish can regenerate its heart after injury, and their studies suggest that understanding cardiac regeneration in this fish may lead to specific strategies to repair damaged human hearts.

Scientists shed new light on the body’s internal clock

As mammals, our internal (circadian) clock is regulated by the patterns of light and dark we experience. But how that information is transmitted from the eye to the biological clock in the brain has been a matter of scientific debate. Scientists had suspected that a molecule called melanopsin, which is found in the retina, plays an important role. Now researchers have confirmed that melanopsin does indeed transmit light information from the eye to the part of the brain that controls the internal clock. According to the researchers, melanopsin may be one of several photosensitive receptors that work redundantly to regulate the circadian system.