Bacillus altitudinis 1.4 genome analysis - functional annotation of probiotic properties and immunomodulatory activity

Abstract

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. They are often used to improve intestinal health. In this study, phenotypic and genotypic methods were used to evaluate the probiotic properties of Bacillus altitudinis 1.4. The isolate was sensitive to all tested antimicrobials and showed a positive result in the hemolysis test. The results also indicated that the spores of B. altitudinis 1.4 were more resistant than the vegetative cells, when evaluated in a simulation of cell viability in the gastrointestinal tract, as well as adhesion to the intestinal mucosa. The isolate was able to self-aggregate and coaggregate with pathogens such as Escherichia coli ATCC 25922 and Salmonella Enteritidis ATCC 13076. Genomic analysis revealed the presence of genes with probiotic characteristics, such as fglA-L, motA, motB, luxS, pgaA-D, exoX, epsG. From this study, it was possible to evaluate the gene expression of pro-inflammatory and anti-inflammatory cytokines for different treatments. Viable vegetative cells of B. altitudinis 1.4 increased the transcription of pro-inflammatory factors, such as TNFα, NFkβ, TLR2, in addition to also increasing the transcription of IL-10, indicating a tendency to stimulate a pro-inflammatory profile. In view of the results presented, B. altitudinis 1.4 showed the potential to be applied in the incorporation of this microorganism in animal feed, since the spores could tolerate the handling and pelleting processes of the feed.