They discover how to promote the presence of good bacteria in the intestine

The millions of bacteria found in the intestine play a key role in both health and disease in humans. Therefore, knowing the mechanisms that help promote the growth of beneficial ones or neutralize those that can do harm is one of the great goals of scientists.

Now, a group of researchers from Yale University in the United States led by the Argentine geneticist Eduardo Groisman, and which includes, among others, Emilia Krypotou, has found the key to the multiplication in the intestine of an abundant bacterium known for its favorable effects for the organism, which could have applications in human health.

It is the bacterium Bacteroides thetaiotaomicron, an “ally” of humans for the digestion of fibers. “We discovered that a protein (Rho) that controls the expression of other proteins forms compartments without a membrane in which their activity is increased, and that this affects the expression of hundreds of genes, many of which are necessary for the bacterium to function. colonize the gut,” Groisman explained.

The process is mediated by a “phase separation”, a biochemical mechanism that has been known for a long time but that began to gain relevance in biology in the last seven years, Groisman explained to the CyTA-Leloir Agency. “Although phase separation had been proven –for other proteins– in test tubes and cultured cells, its role in a living being had not been demonstrated. Our work becomes the first example of the role of phase separation and membrane-free compartment formation in an organism,” he added.

Eduardo Groisman (center) with members of the research team. (Photo: Yale University / CyTA-Leloir Agency)

Nutrient availability seems to trigger the mechanism. Groisman and his team found that limiting carbon – a basic component of cells – increases the presence of these membrane-free compartments, which favors the survival of Bacteroides in the mammalian intestine.

“As diet is one of the factors determining the abundance of different bacterial species in the human intestine, we are now completing a report that will try to explain the biological significance and practical applications of our results. For example, what about diets that include fasting for different periods of time, which for these bacteria may represent periods of nutrient limitation,” Groisman anticipated.

Previous studies by other groups of researchers had found that Bacteroides thetaiotaomicron is found more often in healthy, lean people and is one of the bacteria important for digesting plant-based fiber that humans cannot properly process without help.

Graciela Boccaccio, head of the RNA Cellular Biology Laboratory of the Leloir Institute Foundation (FIL) and specialist in the study of membrane-less organelles, welcomed the publication of the study in Science. “The work is highly relevant. It is a compelling example that liquid-liquid phase separation and the formation of biocondensates or MLOs occur in Bacteroides, expanding the scope of this biochemical mechanism throughout evolution and supporting the idea that it is ‘as old as life,’” said the scientist, who was not involved in the research. And she concluded: “It is a very valuable contribution not only from the theoretical, but also with future perspectives in biomedicine.”

The study is titled “Bacteria require phase separation for fitness in the mammalian gut”. And it has been published in the academic journal Science. (Source: CyTA-Leloir Agency)