Bacteroides are present in a large percentage of healthy adult microbiomes in western cultures. They have great potential for uncovering what makes a healthy microbiome for human hosts and what causes gastrointestinal diseases like inflammatory bowel disease (IBD). Bacteroides spp. have contractile injection systems (CIS) known to mediate bacterial-bacterial interactions in the gut, but a separate gene cluster encoding a related CIS was identified and suspected to be involved in bacterial-eukaryotic interactions. This gene system, named Bacteroidales injection system, or BIS, has similarities to the CIS found in other bacterial species that induce metamorphosis in their eukaryotic partners, making them a symbiotic relationship. To detect BIS production from Bacteroides cellulosilyticus, strains with different knocked out genes were created and verified protein absence via western blot confirmation. Effector proteins are commonly injected via these contractile systems and genes encoding potential effectors have also been identified for BIS. To characterize how the BIS elicits host responses through delivery of bioactive effector proteins, these effector genes were inserted into plasmid vectors and assessed for viability in E. coli to further study these genes.
