Lactobacillus rhamnosus GG does not increase Caenorhabditis elegans longevity

Caenorhabditis elegans is used as a model organism to study longevity. In recent years, C. elegans have helped advance knowledge regarding the human microbiome and host-pathogen interactions due to its characteristic as a bacterivore. Studies have reported that a strain of Lactobacillus rhamnosus, CNCM I-3690, enhances the lifespan of C. elegans by inducing the expression of genes under the control of the DAF-16 transcription factor. Although the effects of pathogens on C. elegans have been well-studied, the effects of a commonly used human probiotic, L. rhamnosus GG (LGG), on C. elegans are not well-characterized. We hypothesized that LGG would enhance longevity in C. elegans in a DAF-16-dependent manner, similar to previous observations of L. rhamnosus CNCM I-3690. Based on a series of survival assays, we observed the lifespan of the wild-type and daf-16 C. elegans fed with E. coli OP50 or LGG. We determined that the lifespans of neither C. elegans strain increased when fed with LGG, which contradicts our hypothesis and contrasts with previous research that has demonstrated that Lactobacilli can enhance C. elegans lifespan. Interestingly, we also observed that starved C. elegans appear to avoid MRS media, which is used to culture LGG.