Research Report: Ever heard of the ‘couch potato mouse’?
By Lynne Friedmann
Sanford-Burnham Medical Research Institute researchers have unveiled a surprising new model for studying muscle function: the couch potato mouse. The mice maintain normal activity and body weight, but do not have the energy to exercise. This because they lack PGC-1, a protein that muscles need to convert fuel into energy.
Normally, physical stimulation boosts PGC-1 activity in muscle cells, which switches on genes that increase fuel storage, ultimately leading to “trained” muscle (the physical condition most people hope to attain through exercise). In obese individuals, PGC-1 levels drop, possibly further reducing a person’s capacity to exercise — creating a vicious cycle. In this study, mice without muscle PGC-1 looked normal and walked around without difficulty, but could not run on a treadmill.
Interest in understanding the factors that allow muscles to exercise is the knowledge that whatever this machinery is, it becomes inactive in obesity, aging, diabetes and other chronic conditions that affect mobility.
Findings are reported in the journal Cell Metabolism. News release at bit.ly/g92ZZh.
Redefining the role of plasma cells
Scientists from The Scripps Research Institute have uncovered a regulatory mechanism in the body’s response to eliminate pathogens, such as bacteria and viruses. The study focused on plasma cells of the immune system which are known for producing large quantities of disease-fighting antibodies. Unexpectedly, plasma cells were shown to also act in a negative feedback loop, the end result of which affects the function of other higher-ranking immune cells.
Previous to this work, scientists thought of plasma cells as simple soldiers in the fight against the body’s foreign invaders and lacking in the ability to direct the course of future immune battles. Thus, the findings challenge a long-held dogma in the field of immunology and have potential implications for far-ranging topics from how vaccines should be administered to the origin of autoimmunity.
Results appear in the journal Nature Immunology: bit.ly/gJVzpz.
Polluted water toxic to Bangladesh economy
The widely reported arsenic contamination of drinking water in Bangladesh has now been shown to have a toxic effect on the struggling nation’s economy. For example, it’s estimated that exposure to arsenic in rural Bangladesh has reduced the labor supply by eight percent. This is larger than the increase in unemployment in the United States from the “Great Recession.” Impact comes in the form of altered work arrangements with women older than 45 working fewer hours outside of the home (as they presumably care for ill family members) while men aged 25 to 65 are working more.
The arsenic problem in Bangladesh dates to the 1970s, when shallow groundwater wells, unwittingly tapping into naturally occurring arsenic in the ground. The present study uses a novel method that could be applied to discovering the effects of other environmental pollutants in developing nations. UCSD researchers are among an international team of economists that is the first to identify a dramatic present-day consequence of the contaminated groundwater wells, in addition to the longer-term health damages expected to occur in coming years.
Findings appear in the American Journal of Agricultural Economics: bit.ly/dW0Zx2.
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