We share our world, and our bodies with microbes. Researchers have been learning a lot more about how specific species of gut microbes affect various aspects of our health and well-being. New work has described a gut bacterium called Taurinivorans muris that exclusively consumes the amino acid taurine, and generates hydrogen sulfide, a stinky gas. This microbe also helps protect us from two kinds of dangerous bacteria that can cause serious infections: Klebsiella and Salmonella. The findings have been reported in Nature Communications.
Hydrogen sulfide causes smelly flatulence, but it's healthy for the gut to carry low levels of the gas; it plays an important role in several biological processes. Gut microbes that generate hydrogen sulfide could deprive pathogens like Klebsiella of the oxygen they need to live and thrive. But higher levels of hydrogen sulfide can become problematic, and promote inflammation and damage to the lining of the gut.
"Hydrogen sulfide may suppress the oxygen-dependent metabolism of some pathogens," explained first study author Huimin Ye.
Bilophila wadsworthia is an important human gut microbe that consumes taurine. Taurinivorans muris is a newly discovered genus of bacteria that consumes taurine and generates hydrogen sulfide. Other gut microbes help Taurinivorans muris access taurine, which needs to be released from bile acids.
Most taurine in the human body comes from foods like dairy, meat, and seafood. Taurine is a player in a wide variety of biochemical pathways in the body, and may be involved in healthy aging. The liver also releases bile acids that contain taurine, and which aid in digestion. Gut microbes can also affect the production of bile acids by the liver.
"The bacterium we described has a rather unbalanced diet; it specializes in consuming taurine," said study leader Alexander Loy of the Center for Microbiology and Environmental Systems Science of the University of Vienna (CeMESS).
This study has helped illuminate some of the details of a complex relationship involving bile acids, taurine, and gut microbes. It has also demonstrated that beneficial gut microbes can have a variety of important roles, including helping to protect us from infection.
"The protective mechanism of Taurinivorans muris against pathogens may be via hydrogen sulfide but is essentially not yet fully understood," Loy noted.