Acholeplasmas and similar nonsterol-requiring Mollicutes from insects: missing link in microbial ecology

Wall-less prokaryotes from the guts of the bibionid Plecia sp. from Peru, and a syrphid, the tabanids Tabanus catenatus and Chrysops discalis and the eumenid Monobia quadridens from Maryland were characterized. The strains grew at 23-32°C in conventional mycoplasma media containing 10% v/v serum, or in serum-free mycoplasma medium with or without fatty acid-Tween 80 supplements. No helical forms were noted in dark-field microscopy, and electron micrographs of thin sections of the strains showed a single membrane. Two strains, DF-2 and MQ-3 from Chrysops and Monobia, respectively, cross-reacted with antiserum against Acholeplasma florum. Although the other 3 strains did not react with Acholeplasma or Mycoplasma spp., they were otherwise characteristic of acholeplasmas. The study suggested that insects may constitute an important reservoir for acholeplasmas.