It’s not as exciting as El Dorado’s source of eternal youth, but nitric oxide-producing bacteria are extending the lifespan of the humble roundworm Caenorhabditis elegans.
The worm lacks the enzyme needed to produce nitric oxide. In animals which are capable of manufacturing nitric oxide, it has been shown to increase blood flow, promote efficient nerve signal transmission and regulate the immune system, all factors that may contribute to a longer lifespan.
To see if nitric oxide alone could extend lifetime, researchers fed a group of C. elegans a soil-dwelling bacterium called Bacillus subtilis, which produces the gas. The worms, with colonies of B. subtilis established in their guts, had a lifespan of about two weeks—nearly 15 percent longer than a control group fed bacteria which didn’t produce nitric oxide.
Statins are widely prescribed to reduce levels of LDL, the “bad cholesterol,” a vital goal in stemming and preventing cardiovascular disease. But they don’t work for everybody, often for inexplicable reasons. Researchers now think some of the blame rests with gut bacteria, that influential yet mysterious group that occupies our bowels and outnumbers our cells 10 to one. In a study published this month in PLoS One, researchers took blood samples from 944 study participants prior to and after six weeks of treatment with a statin called simvastatin. They measured the levels of various bile acids, many of which are produced by gut bacteria and help metabolize fat by acting like detergents, allowing cholesterol to be dissolved and transported in the blood. The researchers found that people whose LDL levels dropped the most had significant quantities of three bile acids produced by a particular type of gut bacteria. Those who responded least to the statins had significantly higher levels of five different bile acids from different gut flora. The researchers hypothesize that bile acids present in the non-responders compete with simvastatin for transporters that ferry both chemicals to the liver, where the drug has its effect.
As the number of bacteria in mosquitoes’ guts (x axis) went up,
the malaria parasite levels dropped faster than a cartoon anvil.
What’s the News: We know the bacteria living in our guts are important to our health—but the bacteria in mosquitoes’ guts could be too. Researchers have discovered a species of mosquito gut bacteria that destroys the malaria parasite, keeping the disease from spreading to humans. This explains why some Anopheles mosquitoes (the only genus that transmits malaria) don’t spread it, and it spurs the imagination towards possible ways of tamping down the disease.
The health detriments of a Western diet—eating foods high in fat, sugar, and animal protein—are now well known. However, according to a group of studies out in this week’s Proceedings of the National Academy of Sciences, how you eat when you’re just a kid can have a great impact, influencing the gut microbes you’ll carry your entire life.
Researchers led by Carlotta de Filippo studied the gut microbes of African children raised in Burkina Faso versus those in European children from Italy. According to the team’s findings, the kids’ diet had a dramatic effect on what bacteria they harbored in their guts to help them with digestion. The Burkina Faso children, who grew up eating a lot of fiber, had gut bacteria that help to break down that tough material. Meanwhile the Italian children, who grew up on a Western diet, had guts dominated by a kind of bacteria that’s more common in obese people, and they had less bacterial diversity overall.
Two other PNAS papers this week took on the formation and evolution of a human’s gut microbiome. One showed how a nursing infant gets its first helpful gut microbes from mother’s milk, and the other followed the same baby for two and a half years—collecting “samples” from diapers—to show how its population of gut bacteria changed and developed.
For an in-depth take on these studies and insight on how they fit together, check out Ed Yong’s post at Not Exactly Rocket Science.
Not Exactly Rocket Science: You Are What You Eat—How Your Diet Defines You in Trillions of Ways
80beats: Scientists Sequence DNA from the Teeming Microbial Universe in Your Guts
80beats: My Excrement, Myself: The Unique Genetics of a Person’s Gut Viruses
Image: Wikimedia Commons