11/11/2023 0 Comments Endospore forming bacteriaThe guinea pig intestinal symbiont Metabacterium polyspora may undergo binary fission but the regular formation of multiple endospores, up to nine from a single mother cell, is a significant form of reproduction. Other lineages within the Firmicutes use multiple endospore formation as a reproductive strategy. These multicellular filaments live attached to the lining of the small intestine, and to disperse or reposition itself in the gut, each cell in a filament forms either an endospore containing two cells or two non-dormant intracellular offspring. Others include the Segmented Filamentous Bacteria, a group of uncultivated inhabitants of the intestinal tract of animals. For example, Clostridium oceanicum regularly forms two endospores, one at each end of the mother cell. While most sporulating species of Firmicutes produce a single endospore, some have the ability to produce multiple endospores. This form of sporulation preserves the genome in a remarkably dispersible and dormant cell type that can resume vegetative growth when the environment improves. Endospores endure environmental conditions that would kill most other bacterial cells, including prolonged periods of insufficient nutrients, moderate levels of organic solvents, exposure to phage, extremes in pH, proteases and cell wall degrading enzymes, freezing, desiccation and excessive heat or radiation. Our findings provide a framework for understanding the evolution of a novel form of cellular reproduction.Įndospore formation is an ancient and complex developmental process exclusive to certain bacteria within the Firmicutes. Low conservation of genes expressed late in endospore formation, particularly those that confer resistance properties and encode germinant receptors, suggest that Epulopiscium has lost the ability to form a mature spore. Genes coding for components of the central regulatory network which govern the expression of forespore and mother-cell-specific sporulation genes and the machinery used for engulfment appear best conserved. ![]() ![]() subtilis sporulation genes used in this analysis, we found 57 homologs in the Epulopiscium genome and 87 homologs in the C. Comparative analysis with the complete genome of its close, endospore-forming relative, Cellulosilyticum lentocellum, identified homologs of well-known sporulation genes characterized in Bacillus subtilis. ![]() To test this, we sequenced the genome of Epulopiscium sp. We hypothesize that intracellular offspring formation in Epulopiscium evolved from endospore formation and these two developmental programs share molecular mechanisms that are responsible for the observed morphological similarities. Instead, it forms multiple intracellular offspring using a process with morphological features similar to the survival strategy of endospore formation in other Firmicutes. type B, a large intestinal bacterial symbiont of the surgeonfish Naso tonganus, does not reproduce by binary fission.
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