Pathogenic strains that undergo PV produce cell types that are less likely to be recognized by the immune system, thus affording these pathogens enhanced opportunities to survive in the host. While human pathogenic strains have been the subject of intense PF-3758309 research, non-human pathogens similarly benefit from phase switching. Photorhabdus luminescens produces M and P- morphotypes during phase variation. The P-form cells, produce larger colonies, more secondary metabolites, and generate more bioluminescence than the smaller M-form cells. The M form is critical for the life cycle of P. luminescens because it is the form that can persist in the nematode host Heterorhabditis bacteriophora. M. xanthus is a nonpathogenic bacterium with a biphasic life cycle comprised of a Thiamet G vegetative phase and a complex developmental phase that together ensure survival in harsh environments. Multiple studies have documented PV in M. xanthus and its effects on vegetative growth, swarming, and development. The predominant morphotype, or variant, in M. xanthus produces a rough, matte colony that is yellow due to production of the polyketide pigment DKxanthene. Yellow variants are proficient at swarming on agar surfaces. Colonies of the other morphotype are tan and generally have a smooth, shiny surface. Tan variants exhibit reduced swarming. The P. luminescens M and P-forms share features in common with the yellow and tan variants of M. xanthus including a property where the one form – the tan variant- can be ingested by bacteriophagous nematodes, while the other form �C the yellow variant – is resistant to the nematode. The ability to produce a variant that is resistant to a predator may enhance survival of M. xanthus in its soil habitat. Yellow and tan colonies do not represent pure populations of either variant type, but rather are dynamic mixtures. Yellow colonies contain cells capable of giving rise to <95% yellow colonies and 5% tan colonies ; these ratios are reversed in the tan variants. The rate of switching from yellow to tan has been reported to be as high as 1022 to 1023 per cell per generation; switching from tan to yellow is higher, so colonies of the yellow variant outnumber those of the tan variant. M. xanthus cells aggregate together to form fruiting bodies filled with heat and desiccation-resistant spores in response to starvation.