2024-02-13 08:00:19
By Communication CEAB-CSIC*
Many people who are dedicated to health insist that we should eat in a balanced way. One of the reasons for doing so is that human beings depend on food to obtain many of the substances essential for the proper functioning of our body. It is the case of the nine essential amino acids: amino acids that our body cannot synthesize by itself. These basic components of proteinsa kind of “bricks” that build them, are key for, among others, the maintenance of muscles, cognitive function or mood regulation.
In the microbial world this It’s a little different. There are bacteria that, as in our case, depend on what they eat to obtain essential amino acids, the so-called ‘auxotrophs’. And others, however, are self-sufficient, that is, they can produce them all by themselves. They are the so-called ‘prototrophs’.
3D model of various bacteria surrounded by amino acids. / CEAB-CSIC
What are the most common? Which microorganisms follow the ‘prototrophic’ strategy and which opt for the ‘auxotrophic’ strategy? Where do each other live? Does the environment in which they live influence the ‘choice’ of one strategy or another?
These are some of the questions that a team made up of research personnel from the Blanes Center for Advanced Studies (CEAB-CSIC) and the universities of Colorado, Aalborg and the Lawrence Berkeley Lab. Its members analyzed with supercomputing more than 26,000 bacterial genomes and environmental DNA from such diverse natural environments such as lakes, oceans, water treatment plants, human microbiota and even foods such as sourdough or cheese. The results of his study have recently been published in the scientific journal Nature Communications.
3D rendering showing bacterial communities in combination with DNA. / CEAB-CSIC
Our intestine: an “free buffet”, ideal for auxotrophic bacteria
The investigation reveals the great weight of the environment in the evolution and genetic adaptation of bacteria. In those environments where nutrients are always available, in these ‘free buffets’ open 24 hours a day, auxotrophs triumph.
Joseph Ramoneda y Emily O. Housekeeper, CEAB-CSIC researchers, explain it like this: “Why would they have to make the effort to manufacture amino acids if they always have them available in their environment? In these environments, the strategy of self-producing them is no longer an advantage. Giving up on it, on the other hand, is very worthwhile: it means spending much less energy and that helps to thrive, to proliferate in these environments.”
Foods such as dairy products or our intestine are clear examples of these. environments, rich in amino acids, in which auxotrophic microbes triumph, those who have lightened their genetic load by losing, among others, the genes involved in the self-production of amino acids. Their evolutionary strategy of genome streamlining gives them a clear advantage in these environments.
On the opposite side are the environments with few available nutrients. Here, due to the difficulty and/or temporality of access to essential amino acids, prototrophic bacteria winthose that have genes that allow them to make themselves what they need to function. This is the case of 80% of microorganismswho find self-sufficiency an advantage to survive in environments where food availability is very low.
The research has been carried out with supercomputing tools. Computational Biology Lab CEAB-CSIC
The work also points out a radical example: a genus of bacteria that have very, very small genomes and that parasitize us. It is about the micoplasmaswhich obtain amino acids from our cells and are implicated in numerous diseases such as pneumonia.
The best The understanding of the ideal living conditions for microbes provided by this research is of great interest for different fields, such as health.. A deep understanding of bacteria and the connections with the environment in which they live can help develop new drugs to combat those that are pathogenic.
* Communication team of the Center for Advanced Studies of Blanes (CEAB-CSIC). This post is based on the article: Ramoneda, J., Jensen, TBN, Price, MN et al. Taxonomic and environmental distribution of bacterial amino acid auxotrophies. Nat Commun 14, 7608 (2023).
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