Bacteria and bacterial products: Foe and friends to Caenorhabditis elegans.

Caenorhabditis elegans is a model organism for the study of different molecular, biochemical, microbial and immunity-related mechanisms. In its natural habitat, C. elegans survives by feeding microorganisms (mainly bacteria), though majorly on Escherichia coli OP50 when grown in the laboratory. Numerous bacteria are shown to influence the lifespan, behavioural responses and innate immunity of C. elegans. The secondary metabolites produced by bacteria have shown to play key role in C. elegans longevity. This behaviour provides insights for potential development of new strategies for the treatment of diseases in other species, including humans. This review explains the concept of C. elegans microbiome, different mechanisms employed in its longevity and resistance against bacterial pathogens and the effects of various bacteria (both beneficial and harmful) as well as their products on the life cycle of C. elegans.