Transcriptional and metabolomic consequences of luxS inactivation reveal a metabolic rather than quorum sensing role for LuxS in Lactobacillus reuteri 100-23

ABSTRACT: Autoinducer-2 (AI-2)-mediated quorum sensing has been extensively studied in relation to the regulation of microbial behaviour. There are however two potential roles for the AI-2 synthase (LuxS). The first is in the production of AI-2 and the second is as an enzyme in the activated methyl cycle where it catalyses the conversion of S-ribosylhomocysteine to homocysteine. The by-product of the reaction catalysed by LuxS is (S)-4,5-dihydroxy-2,3-pentanedione (DPD), which spontaneously forms the furanones known collectively as AI-2. The mammalian gastrointestinal tract contains a complex collection of bacterial species so a method of interspecies communication might influence community structure and function. Lactobacillus reuteri 100-23 is an autochthonous inhabitant of the rodent forestomach where it adheres to the non-secretory epithelium of the forestomach forming a biofilm. Microarray comparisons of gene expression profiles of the L. reuteri 100-23 wild type and a luxS mutant under different culture conditions revealed altered transcription of genes encoding proteins involved in cysteine biosynthesis, the oxidative stress response and cell wall proteins. Metabolomic analysis revealed that the luxS mutation affected cellular levels of fermentation products, fatty acids and amino acids. Cell density-dependent changes (log phase versus stationary phase growth) in gene transcription were not detected. Overall, the results indicated that AI-2 was unlikely to be involved in gene regulation in L. reuteri 100-23 in a classical quorum-sensing type manner. Analysis of the microarray data was obtained from two or more independent biological replicates.

ORGANISM(S): Lactobacillus reuteri 100-23

SUBMITTER: Charlotte Wilson 

PROVIDER: E-GEOD-32520 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress