Physicochemical and transcriptomic responses of Lactobacillus brevis JLD715 to sodium selenite

Elemental selenium, as a new type of selenium supplement, can be prepared by microorganisms reducing inorganic selenium. In this study, Lactobacillus brevis JLD715 was incubated in broth containing different concentrations of sodium selenite (Na₂ SeO₃ ).

The results showed that the bacterial biomass of L. brevis JLD715 decreased due to the inhibition of Na₂ SeO₃ . The cell membrane of L. brevis JLD715 treated with Na₂ SeO₃ was damaged, as evidenced by the reduction of intracellular ATP concentration, depolarization of cell membrane, reduction of intracellular pH and impairment of membrane integrity. In addition, we investigated the metabolism mechanism of Na₂ SeO₃ by L. brevis JLD715 based on transcriptome sequencing. A total of 461 genes were significantly differentially expressed under Na₂ SeO₃ treatment, of which 231 genes were up-regulated and 230 genes were down-regulated. These genes were involved in pathways such as pyruvate metabolism, fatty acid biosynthesis, selenocompound metabolism and nucleotide-binding oligomerization domain-like (NOD-like) receptor signaling. Meanwhile, the genes related to sulfhydryl oxidoreductase, electron carrier proteins and transmembrane transport proteins synthesis were significantly up-regulated.

To sum up, the findings of this research will contribute to providing support for the application of L. brevis JLD715 in selenium-enriched functional foods. © 2021 Society of Chemical Industry.