Subsequent infection differentially affects the proteome of Caenorhabditis elegans by abrogating the intestinal cell proliferation.

With a wide range of bacterial infections growing, it has become a big challenge to the research field to combat the newly emerging diseases. Immuno-compromised patients are vulnerable to opportunistic infections. P. mirabilis, an opportunistic pathogen infects the nematode when the immune system is compromised. In the present study, the C. elegans was pre-exposed to S. aureus for a short term, and then consecutively infected with P. mirabilis. The primary infection caused by S. aureus makes the immune system of C. elegans vulnerable making it easy for P. mirabilis to colonize efficiently during subsequent exposure, thereby stimulating the immune system of the nematode. In this study, the C. elegans exposed to the pathogens (S. aureus 4 h/P. mirabilis 40 h and S. aureus 8 h/P. mirabilis 60 h time points) showed a substantial difference in the banding patterns of SDS-PAGE gel, when compared to their respective OP50 fed controls. 2-DE identified a total of 235 proteins from all the time points which had >2 fold regulation. The regulated protein spots were identified by MALDI-ToF/ToF analysis and one common protein CDC-25.1 was found to be regulated in all the comparative time points. CDC-25.1 seemed to down regulate during subsequent infection and up regulate in single infection. The transcriptomic regulation of cdc-25.1 also reflects the protein regulation. In addition to it, survival assay in cdc-25.1 mutant nematodes confirm the susceptibility of host during subsequent infection.

Significance of probiotics in remodeling the gut consortium to enhance the immunity of Caenorhabditis elegans.

In the recent past, Caenorhabditis elegans has emerged as one of the leading nematode models for studying host-microbe interactions on molecular, cellular, or organismal levels. In general, morphological and functional similarities of the gut of C. elegans with respect to that of human has brought in speculations on the study of the intestinal microbiota. On the other hand, probiotics have proved their efficacy in metabolism, development, and pathogenesis thereby inducing an immune response in C. elegans. Nurturing C. elegans with probiotics has led to immunomodulatory effects in the intestinal microbiota, proposing C. elegans as one of the in vivo screening criteria to select potential probiotic bacteria for host health-promoting factors. The major prospect of these probiotics is to exert longevity toward the host in diverse environmental conditions. The extent of research on probiotic metabolism has shed light on mechanisms of the immunomodulatory effect exerted by the nematode model. This review discusses various aspects of the effects of probiotics in improving the health and mechanisms involved in conferring immunity in C. elegans.