The Mollicutes are cell wall-free prokaryotes thought to be the smallest free-living organisms in existence Many, although not all, are pathogenic. Members of the genus Mycoplasma are animal parasites and tend to colonize the mucus membranes of the respiratory and urogenital tracts, often causing diseases that are confined to those sites. Those able to penetrate the mucosal barrier frequently show a tropism for the joints, and arthritis is a common primary or secondary manifestation of mycoplasmal infection. Mycoplasma arthritidis-induced arthritis of rats is an acute, self-limiting, migratory polyarthritis affecting primarily the periphery joints. It is an old and well-established model for some of the inflammatory and immunological aspects of human arthritis and is also quite similar to mycoplasmal arthritides of larger economically important, animals. However, until recently, very little was known about M. arthritidis virulence factors. It is now clear that virulence is heavily influenced by the presence of temperate bacteriophage MAV1. Lysogenized strains are highly virulent, while nonlysogenized strains arc avirulent or induce only low-grade oligoarthritis. Identification of putative virulence factors carried by MAV1 is the subject of another proposal on which the PI is a co- investigator; however, many other aspects of the interaction between MAV1 and its host have yet to be characterized. The primary aim of this project is to begin to characterize mechanisms of MAV1 integration into the host chromosome. Additional information on mechanisms of DNA replication (e.g., whether circular intermediates are present and whether MAV 1 actually functions like a transposon) will also be collected; MAV1 absorption to host cells will be characterized, and the MAV1 specific receptors on the mycoplasmal surface identified. Although it has been known for a long time that these small and simple organisms, the mycoplasmas, can themselves be parasitized by yet smaller entitIes, these phages have proven elusive and difficult to work with, partly because their hosts also display those traits. However, with the increased availability of molecular techniques allowing analysis of very small samples, our understanding of these fascinating and potentially important entities is increasing. This study should add to that understanding.
| Washburn, L R; Miller, E J; Mukherjee, S et al. (2004) Mycoplasma arthritidis bacteriophage MAV1 prophage integration, deletions, and strain-related polymorphisms. Plasmid 52:31-47 |
