The C. elegans proteome response to alternative food source bacteria

Understanding how C. elegans interacts with the bacteria it feeds upon enables us to better comprehend the complex interactions occurring at the interface of host and microbe. Here we have assessed the proteome of C. elegans after growth on bacteria capable of colonising the gut via a comparative analysis of C. elegans grown on two environmentally obtained species of Ochrobactrum (MYb71 and MYb237) verses C. elegans grown on E. coli OP50. A total of 4,677 C. elegans proteins were identified, with quantification under our criteria possible for more than 84% (3,941) of these proteins. Significant alterations in protein abundances were observed for 122 proteins, 48 higher in abundance and 74 lower in abundance. We observed an increase in abundance of proteins potentially regulated via host signalling pathways, in addition to several proteins involved in the breakdown and detoxification of foreign entities (e.g. lipase, proteases, glutathione metabolism). Of the proteins decreased in abundance, a number are involved in both degradation (branch chain amino acids) and biosynthesis (cysteine, methionine, glycine, serine and threonine) of amino acids. While enzymes associated with the degradation of peptidoglycan were also less abundant (Lys-4, Lys-5). The differences observed in C. elegans following growth on alternative food source bacteria, as opposed to the normal E. coli OP50, help to highlight the subtle nuances that are, more often than not, overlooked in classical host pathogen studies.