Molecular Approaches to Characterization of Mycoplasmal Adhesins

The mycoplasmas (class Mollicutes) constitute a very large and widespread group of parasitic prokaryotes, causing a variety of diseases in man, animals, plants and insects (Razin, 1978; Razin and Barile, 1985). They are distinguished from other prokaryotes by the total lack of a cell wall and by their minute dimensions. In fact, mycoplasmas can be considered as the smallest self-replicating organisms, closest to the concept of a “minimal cell” (Morowitz, 1984). The presence of only one membrane type, the plasma membrane, in mycoplasmas, combined with the ease of membrane isolation and manipulation of its lipid components, contributed to the establishment of this membrane as one of the most useful experimental models in membrane research (Razin, 1981). Recognition of the mycoplasma genome as the smallest among self-replicating organisms has a great appeal for those studying molecular biology, genetics and evolution, leading to significant progress in these aspects of recent mycoplasma research (Razin, 1985a; Woese, 1987). The great majority of mycoplasmas, which parasitize man and animals, colonize the epithelial linings of the respiratory and urogenital tracts.