Effects of Potential Probiotic Lactic Acid Bacteria on Survival, Stress, and Development of Caenorhabditis elegans

The benefits of having a diverse gut microbiome are supported by a variety of sources across many species. A human diet supplemented with probiotics is found to promote digestion and support immune function. We observed the probiotic capabilities of Lactococcus lactis and Leuconostoc mesenteroides in the gut of C. elegans to investigate benefits and potential therapeutic applications relating to survival, stress, and development. Treatments of all studies consisted of a standard laboratory diet of E. coli strain OP50, lactic acid monocultures, and OP50 supplemented with either lactic acid bacteria. Survival and development studies were conducted using wild type worms C. elegans. Stress studies were conducted using transgenic worm strains containing fluorescent stress reporters to indicate reactive oxygen species stress, cytoplasmic, endoplasmic reticulum, and mitochondria unfolded protein response. Both potential probiotic strains demonstrated an overall health span benefit. A correlation was detected between survival and stress response. Homeostasis of C. elegans was better maintained with the presence of lactic acid bacteria when stressed. Also, a survival increase was observed in worms given the probiotic supplements compared to OP50 alone. Development studies showed slight difference between OP50 and other treatments but not enough to affect the overall lifespan of the worm. Stress and survival study results demonstrate the potential probiotic effects of L. lactis and L. mesenteroides in C. elegans. Biomarkers of reduced stress observed in these studies could be used in as an indicator of overall health. Development results showed the lactic acid bacteria increased the development by 1-2 hours, which is not significant in C. elegans short lifespan, but could show a significant difference in a more complex species with a longer average lifespan.