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The human gut homes some good bacteria which only lately has been proven to be beneficial for the human body. The good bacteria are capable of reducing the risk of heart disease.
The production of the chemical responsible for clogged arteries reduces due to the good bacteria’s activity in the intestine. After being manufactured in the gut, the chemical enters the bloodstream and travels all the way to the liver. There it is converted into its most harmful form.
After tracing the bacteria’s behaviour to a family of proteins, a group of researchers from the Ohio State University suspects they could be furthermore beneficial for the body. Bad bacteria and these microbes fight for the same nutrients in the gut–and if the good bacteria win, they may boost the body’s metabolism.
The scientists are hopeful that this good bacterium, Eubacterium limosum, can be used for therapeutic purposes in the future. Previous research has already shown the bacteria is “good” because it calms inflammation in the gut.
“Over the last decade, it has become apparent that bacteria in the human gut influence our health in many ways. The organism we studied affects health by preventing a problematic compound from becoming a worse one,” said Joseph Krzycki, professor of microbiology at Ohio State and senior author of the study. “It’s too soon to say whether this bacterium could have therapeutic value. But that’s what we’re working toward,” added Krzycki.
The findings of the research will be published in the upcoming edition of the Journal of Biological Chemistry.
The chemical that is linked to the clogged arteries and characterizes atherosclerosis is called trimethylamine, or TMA. TMA is produced when the bad bacteria interacts with certain nutrients like L-carnitine (found in meat and fish) from food.
Discoveries of the study reveal that E. limosum interacts with L-carnitine in a different way in the gut and that interaction eliminates L-carnitine’s role in the production of TMA (other nutrients also participate in TMA production in the gut). The researchers attribute the bacteria’s beneficial behaviour to a protein called MtcB, an enzyme that cuts specific molecules off of compounds to help bacteria generate energy and survive.
This is called the process of demethylation. It involves the removal of one methyl group–a carbon atom surrounded by three hydrogen atoms–to change a compound’s structure or function.
Krzycki says “The bacteria do this for its own benefit, but it has the downstream effect of reducing the toxicity of TMA.” He adds that, “Up until now, the only known gut microbial reactions with L-carnitine involved converting it into its bad form. We’ve discovered that a bacterium known to be beneficial could remove a methyl group and send the resulting product down another pathway without making any other harmful compounds in the process.”
In these interactions, L-carnitine functions as a compound consumed so the organism can live and grow, and also a target for enzyme activity. In the study, the researchers fed E. limosum cultures an assortment of potential substrates, including L-carnitine. Only when offered L-carnitine did the microbe synthesize the MtcB protein specifically to lop off L-carnitine’s methyl group. It is safe to say that MtcB is part of the bacteria’s natural way to consume the nutrient.
Krzycki expresses that this study has indicated that there is clearly a lot more to study about gut bacteria, its health benefits, and its effects on metabolism.
“MtcB is part of a family of proteins with thousands of representatives that may use different compounds and change what nutrients bacteria consume in the gut,” he said. “These proteins may behave very similar chemically, but using different compounds obviously can create big changes as far as biology goes.”