Transcriptional regulation of agmatine deiminase pathway in Enterococcus faecalis was adapted to respond to oral and gastrointestinal mileu. A bioinformatic aproach

ESPARIZ, M; SUAREZ, CRISTIAN; BLANCATO, VS; MAGNI, C

San Miguel de Tucuman

Simposio; IV Simposio Internacional de Bacterias Lácticas (SIBAL); 2013

CERELA

Polyamines (PAs) (putrescine, spermidine and spermine) are bioactive compounds present in all living cells. PAs have been described in association with a wide variety of biological reactions, including cellular growth, proliferation, stress response, allergy and inflammatory regulation. In mammals, agmatine absorption and PA concentration in the intestinal lumen are mainly dependent on colonic microbiota. Enterococcus faecalis is a homofermentative lactic acid bacterium (LAB) which is an important nosocomial opportunistic pathogen responsible for bacteremia, endocarditis and infections in immunocompromised patients. Despite this, E. faecalis is frequently isolated from diverse types of commercial and traditional food products and is part of the normal human diet around the world. E. faecalis is able to convert agmatine to putrescine; hence it could increase the amount of the latter compound directly in the gastrointestinal tract of mammals or the exogenous putrescine present in food. In this study we analyzed the presence of genes of the agmatine deiminase system (AgDI) in available genome sequences. We found AgDI coding genes in both prokaryotic and eukaryotic organisms. They were found in commensal and industrial microorganisms such as Lactococcus, Lactobacillus and Clostridium species but also in pathogenic microorganisms and microorganisms non-phylogenetically related to LAB such as fusobacteria and coriobacteria. We identified the presence of at least three different types of protein regulators: AguR, RpiR and MerR. Though, AguR-coding genes have been previously reported in S. mutans and L. lactis, we also found them codified in the phylogenetically distant bacteria Clostridium clostridioforme, Olsenella uli, Sebaldella termitidis, and Eggerthella. Interestingly, albeit their lineage differences, all these microbes cohabit the oral cavity and/or the gastrointestinal tract. The similar architecture of the AgDI system operon and the high degree of homology among their respective components suggest this system has represented an adaptive advantage to colonize either the oral and/or the gastrointestinal milieu. Since agmatine is a novel endogenous regulatory compound of intracellular processes in humans and considering that PA produced by intestinal microbiota affects host welfare, we would expect that function of the AgDI system and the regulation exerted by AguR in oral and/or gastrointestinal bacteria will acquire more relevance in the future.