Probiotic Capability of Lactococcus lactis and Leuconostoc mesenteroides Bacterial Strains When Used to Supplement the Diet of Caenorhabditis elegans and the Potential Effects on Worm Longevity, Stress, and Development

There are a variety of sources supporting the benefits of a diverse gut microbiome on longevity and quality of life across many species. A human diet supplemented with probiotics is found to promote digestion and support immune function. In this study, we propose to investigate the probiotic capabilities of Lactococcus lactis and Leuconostoc mesenteroides in the gut of C. elegans to understand if they have potential therapeutic applications. Preliminary lifespan studies suggest that worms given a diet closer to their natural microbiome (CeMBio) live longer than worms given the standard laboratory diet, OP50, E. coli. Our study has shown that when CeMBio is supplemented with L. lactis or L. mesenteroides the median lifespan decreases. This difference in longevity could be due to a decrease in variability introduced by the probiotic supplementation to an already healthy microbiome. To detect potential probiotic benefits of these microbes, lifespan and health span studies will be conducted using wild type worms and transgenic strains containing fluorescent stress reporters. Worms will be fed a standard laboratory diet of OP50, simulating an unhealthy and undiversified microbiome, supplemented with L. lactis and L. mesenteroides. The stress reporters used in this study will indicate metabolic, environmental, or chemical stress within the experimental system. Stress pathways will be studied along with classical development assays to see the range of potential therapeutic benefits provided by L. lactis or L. mesenteroides within an unhealthy and undiversified microbiome.