Bacteria can be cheaters too
Strategy to save resources uncovered at the molecular level
Some strains of the pathogen Enterococcus faecalis are able to make a call for war against the host immune system but then rely on the weapons of other bacteria, sparing their own resources. This cheating beaviour is now pinpointed at the molecular level by ITQB/IBET researchers from the SAVE Lab and collaborators and published in the journal Microbiology.
In a process known as quorum-sensing bacteria are able to side up with each other, behaving as a single entity. Enterococcus faecalis uses this ability to trigger the production of proteases that are able to degrade antimicrobial peptides produced by the host. A few strains, however, produce the quorum-sensing molecule but do not respond with the concomitant protease production, even though the corresponding genes (operon fsr) are present. What researchers found is that a single mutation renders one of these proteins (histidne kinase FsrC) inactive, thus causing the deafness to the population’s call.
Researchers believe that cheating can be beneficial for these strains. By producing the quorum-sensing signal but not responding to it, bacteria gain a metabolic advantage while profiting from the response of other bacteria.
The incongruent gelatinase genotype and phenotype in Enterococcus faecalis are due to shutting off the ability to respond to the gelatinase biosynthesis-activating pheromone (GBAP) quorum-sensing signal
Neuza Teixeira1,2, Sofia Santos1,Paulo Marujo1, Ryoji Yokohata3, Vijayalakshmi S. Iyer4, Jiro Nakayama3, Lynn E. Hancock4, Pascale Serror5,6 and Maria de Fátima Silva Lopes1,2
1- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Portugal
2- IBET, Portugal
3 - Faculty of Agriculture, Kyushu University, Japan
4 - Division of Biology, Kansas State University, USA
5 - INRA, France
6 - AgroParisTech, France