All of these stories have appeared since last December. There's an amazing amount going on in this field of research, but it hasn't yet reached the public consciousness.
http://www.physorg.com/news/2011-02-gut-bacteria-functions.htmlBacteria in the human gut may not just be helping digest food but also could be exerting some level of control over the metabolic functions of other organs, like the liver, according to research published this week in the online journal mBio. These findings offer new understanding of the symbiotic relationship between humans and their gut microbes and how changes to the microbiota can impact overall health.
"The gut microbiota enhances the host's metabolic capacity for processing nutrients and drugs and modulates the activities of multiple pathways in a variety of organ systems," says Sandrine Claus of the Imperial College of London, a researcher on the study.
http://www.sciencedaily.com/releases/2011/04/110407141328.htmIn just six years, bacteria in the genus Rickettsia spread through a population of the sweet potato whitefly (Bemisia tabaci), an invasive pest of global importance. Infected insects lay more eggs, develop faster and are more likely to survive to adulthood compared to their uninfected peers. . . .
"It's instant evolution," said Molly Hunter, a professor of entomology in the UA's College of Agriculture and Life Sciences and the study's principal investigator. "Our lab studies suggest that these bacteria can transform an insect population over a very short time." . . .
In addition to the observed evolutionary advantages -- which biologists call fitness benefits -- Hunter's team discovered that the bacteria manipulate the sex ratio of the whiteflies' offspring by causing more females to be born than males.
According to Hunter, the bacteria are transmitted only through the maternal lineage (from mother to offspring). Therefore, it is beneficial for them to make sure more female than male whiteflies are born.
http://www.sciencedaily.com/releases/2011/02/110201083928.htmA team of scientists from around the globe have found that gut bacteria may influence mammalian brain development and adult behavior. The study is published in the scientific journal PNAS, and is the result of an ongoing collaboration between scientists at Karolinska Institutet in Sweden and the Genome Institute of Singapore.
The research team compared behavior and gene expression in two groups of mice -- those raised with normal microorganisms, and those raised in the absence of microorganisms (or germ-free mice). The scientists observed that adult germ-free mice displayed different behavior from mice with normal microbiota, suggesting that gut bacteria may have a significant effect on the development of the brain in mammals.
The adult germ-free mice were observed to be more active and engaged in more 'risky' behavior than mice raised with normal microorganisms. When germ-free mice were exposed to normal microorganisms very early in life, as adults they developed the behavioral characteristics of those exposed to microorganisms from birth. In contrast, colonizing adult germ-free mice with bacteria did not influence their behavior.
http://blogs.discovermagazine.com/notrocketscience/2010/11/01/gut-bacteria-change-the-sexual-preferences-of-fruit-flies/Imagine taking a course of antibiotics and suddenly finding that your sexual preferences have changed. Individuals who you once found attractive no longer have that special allure. That may sound far-fetched, but some fruit flies at Tel Aviv University have just gone through that very experience. They’re part of some fascinating experiments by Gil Sharon, who has shown that the bacteria inside the flies’ guts can actually shape their sexual choices. . . .
Sharon was inspired by experiments by Diane Dodd, who raised two strains of fruit flies on different diets, and found that after 25 generations, their menus had affected their sex lives. Those reared on a menu of starch preferred to mate with other ‘starch flies’, while those reared on maltose had a bias towards ‘maltose flies’. These results were odd. Dodd had set up an artificial evolutionary pressure for diet but somehow, the flies’ mating habits had changed as well.
To work out why, Sharon repeated Dodd’s experiment with the fly Drosophila melanogaster, and raised two strains on either molasses or starch. After just two generations, she found the same effect that Dodd did: the flies were more attracted to individuals reared on the same diets. Something in their food was changing their behaviour. . . .
As further evidence, Sharon isolated bacteria from the food that the flies had eaten and added them to vials of sterile food. When the antibiotic-treated flies ate this food, laced with a drizzle of bacteria, they regained their sexual preferences after a single generation. Those that ate food containing ‘starch bacteria’ preferred to mate with starch flies, and those that ate food containing ‘molasses bacteria’ preferred to mate with molasses flies.
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