Long-Term Antibiotic Use Affects "Good" Gut Bacteria

sea-maid submitted, created time 1 month 2 weeks (health.yahoo.com)

Antibiotic treatment, especially when prolonged or repeated, may have a negative impact on beneficial bacteria that live in the gut, according to a new study.

Gut bacteria play helpful roles in various aspects of human nutrition, metabolism and immune responses, experts note.

Researchers focused on the widely-used antibiotic ciprofloxacin, prescribed for a number of bacteria-caused conditions, including urinary tract infections. It has been believed that ciprofloxacin causes only modest harm to beneficial bacteria in the body.

In this study, Stanford University's Dr

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Mutualism alters fish behavior

Darkfrog submitted, created time 3 months 1 week (www.nature.com)

A type of fish called the cleaner wrasse seems to haev a calming effect on local predators. The wrasse eat parasites off the scales of larger fish and even provide what Nature writers have called "a calming massage" with their fins. In return, the client fish keep returning to the wrasses' territory to provide them with more food.

However, what researchers have recently noticed is that client fish stop hunting each other while in wrasse territory--even while they are waiting to be served.

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How to Keep a Wasp from Cheating

Vincent submitted, created time 9 months 3 weeks (sciencenow.sciencemag.org)

It would be easy for fig wasps to cheat. These tiny insects pollinate figs in exchange for a share of the tree's seeds--and theoretically, the wasps could lay claim to more seeds than they deserve. But they don't, and now biologists know why. Parasitic wasps, usually thought of as the bad guys, keep the pollinators honest.

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Mmmm � Bacteria

Interaction between innate immune cells and a bacterial type III secretion system in mutualistic and pathogenic associations

Dolly submitted, created time 1 year 7 months (www.pnas.org)

Animals house a community of bacterial symbionts in their digestive tracts that contribute to their well being. The medicinal leech, Hirudo verbana, has a remarkably simple gut population carrying two extracellular microbes in the crop where the ingested blood is stored. This simplicity renders it attractive for studying colonization factors. Aeromonas veronii, one of the leech symbionts, can be genetically manipulated and is a pathogen of mammals. Screening transposon mutants of A

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Evolution of symbiosis

BIOBOSS submitted, created time 1 year 8 months (www.eurekalert.org)

The aphid Acyrthosiphon pisum depends on a bacterial symbiont, Buchnera aphidicola, for amino acids it can't get from plants. The aphid, in turn, provides the bacterium with energy and carbon as well as shelter inside specialized cells.

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