A group of US researchers led by Argentine geneticist Eduardo Groisman revealed, through a study published in the journal Science , the key to the multiplication in the intestine of an abundant bacteria known for its favorable effects on the organism. Although the study was in mice, it could have future applications in human health.
This 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 membrane-less compartments in which its activity increases, and that this affects the expression of hundreds of genes, many of which are necessary for the bacteria to colonize the intestine,” explained Groisman, from the Department of Microbial Pathogenesis at Yale University School of Medicine, in New Haven, United States.
The process is mediated by “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 told the CyTA-Leloir Agency . “Although phase separation had been proven – for other proteins – in test tubes and cells in culture, its role in a living being had not been demonstrated. “Our work becomes the first example of the role of phase separation and the formation of membrane-less compartments in an organism,” he added.
The availability of nutrients seems to trigger the mechanism. Groisman and his team verified that if carbon – a basic component of cells – is limited, the presence of these membraneless compartments increases, which favors the survival of Bacteroides in the intestine of mammals.
“As diet is one of the factors that determines the abundance of different bacterial species in the human intestine, we are now writing an article that will try to explain the biological significance and practical applications of our results. For example, what happens with diets that include fasting for different periods of time, which these bacteria may perceive as nutrient limitation,” Groisman anticipated to the CyTA-Leloir Agency.
Previous studies by other groups of researchers had determined that Bacteroides thetaiotaomicron is found more frequently in healthy, lean people and is one of the bacteria important for digesting plant-based fiber that humans cannot process on their own.
Graciela Boccaccio, head of the RNA Cellular Biology Laboratory of the Leloir Institute Foundation (FIL) and specialist in the study of membrane-less organelles, celebrated 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 occurs in Bacteroides, which expands the scope of this biochemical mechanism throughout evolution and supports the idea that it is ’as old as life,’” said the scientist, who did not participate in the research. And she concluded: “It is a very valuable contribution not only from a theoretical perspective, but also with future perspectives in biomedicine.”
