CAB researchers discover how bacterium Bacillus subtilis releases media copies of its genome


The team, formed by Olga Zafra, María Lamprecht and Carolina González, and directed by Eduardo González-Pastor, from the Department of Molecular Evolution of CAB, has shown that a population of B. subtilis is able to coordinate the release of DNA to the environment and its uptake by other individuals of the population, which is very important from an evolutionary point of view.

Extracellular DNA (eDNA, for its acronym in English) is free genetic material that is found in the environment where microorganisms live, due to the cell death of the same or through a specific release that can be made by certain microorganisms. Among its possible functions are its use as a nutrient, the ability to help in the cohesion of cells within microbial communities and can also contribute to the transfer of genetic material between the same or different species.

Bacillus Subtilis is a non-pathogenic bacteria present in many types of ecosystems that is commonly used as a model in laboratories. However, for the study of various phenomena of social behavior, a strain of natural origin that lacks possible artificial adaptations to laboratory conditions is used.

Evolution by horizontal transfer

In this work, the natural strain of B. subtilis 3610 has been used and it has been discovered that it is capable of releasing numerous copies of your genome in a specific way and not related to the breakdown of the cell. This led to think that this phenomenon has an important function for the bacteria. It has been shown that the secretion of DNA to the environment is clearly related to another phenomenon called "competence", which is the ability to capture and integrate in the chromosome of the bacteria an external genetic material. Thus, in this particular case, the function of the extracellular DNA is related to the horizontal genetic exchange between bacteria.

The horizontal genetic exchange is a form of microbial evolution in which there is horizontal inheritance, that is, no parents to children, but between individuals of the same generation. In addition, it allows the exchange of large fragments of genetic information. It would be the mechanism by which pathogenic bacteria in hospitals are able to disperse properties such as resistance to certain antibiotics. Therefore, it is a phenomenon of great practical importance, in addition to ecological, and its study at the basic research level is essential since it can help us answer questions about the evolution and diversification of life in its earliest stages.


Fuente: UCC-CAB

Fecha: 2012-12-13


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