Gene expression profiling of the urease operon of a Lactobacillus strain isolated from the prairie vole gastrointestinal tract

Some bacteria such as Helicobacter pylori can sense their environment and use urease to produce ammonia and carbon dioxide when exposed to acidic conditions. This will neutralize the surrounding microenvironment and potentially promote survival in conditions such those in mammalian stomachs. Lactobacilli are common commensals in the gastrointestinal tract and some strains are associated with beneficial effects on the host.

Whole genome sequencing revealed a urease operon in the prairie vole Lactobacillus strain PV034. In order to functionally characterize the urease operon, we analyzed the mRNA expression of the nine genes encoded in the operon when PV034 was grown in various conditions. The strain was cultured in de Man-Rugosa Sharpe (MRS) medium in different pH conditions (2, 4, 6, 8) with and without the presence of urea. Total RNAs were isolated from the bacterial cells and cDNAs were generated. The expression of the urease operon and several housekeeping genes were analyzed using reverse transcription-quantitative PCR. Statistical tests were performed to identify differential gene expression. A detailed mRNA expression profile of the PV034 urease operon will be presented.

This study provides insights into the gene regulation of the urease operon, which is potentially a crucial colonization factor for some Lactobacillus strains in the mammalian gastrointestinal tract. Future studies will be directed towards characterization of the in vivo role of urease production by lactobacilli.