A thermophilic, acidophilic procaryote lacking a cell wall has been isolated from a coal refuse pile which had undergone self-heating. Electron micrographs, chemical assays for hexosamine, and the inability of vancomycin to inhibit growth confirm the lack of a cell wall. The apparent ability of the organism to reproduce by budding and the low guanine plus cytosine content of its DNA indicate a relation to the mycoplasmas. The temperature optimum of the organism is 59 degrees C, and growth occurs over a range of 45 degrees to 62 degrees C. No growth occurs at 37 degrees C or at 65 degrees C. The optimum pH for growth is between 1 and 2, and growth occurs between pH 0.96 and 3.5 but does not occur at pH 0.35 and only poorly at pH 4.0. We propose to call this organism Thermoplasma acidophila. The existence of this organism extends considerably the range of habitats in which mycoplasma may occur.

Expression studies have shown that the coronavirus small envelope protein E and the much more abundant membrane glycoprotein M are both necessary and sufficient for the assembly of virus-like particles in cells. As a step toward understanding the function of the mouse hepatitis virus (MHV) E protein, we carried out clustered charged-to-alanine mutagenesis on the E gene and incorporated the resulting mutations into the MHV genome by targeted recombination. Of the four possible clustered charged-to-alanine E gene mutants, one was apparently lethal and one had a wild-type phenotype. The two other mutants were partially temperature sensitive, forming small plaques at the nonpermissive temperature. Revertant analyses of these two mutants demonstrated that the created mutations were responsible for the temperature-sensitive phenotype of each and provided support for possible interactions among E protein monomers. Both temperature-sensitive mutants were also found to be markedly thermolabile when grown at the permissive temperature, suggesting that there was a flaw in their assembly. Most significantly, when virions of one of the mutants were examined by electron microscopy, they were found to have strikingly aberrant morphology in comparison to the wild type: most mutant virions had pinched and elongated shapes that were rarely seen among wild-type virions. These results demonstrate an important, probably essential, role for the E protein in coronavirus morphogenesis.

BackgroundMassive die-offs of little brown bats (Myotis lucifugus) have been occurring since 2006 in hibernation sites around Albany, New York, and this problem has spread to other States in the Northeastern United States. White cottony fungal growth is seen on the snouts of affected animals, a prominent sign of White Nose Syndrome (WNS). A previous report described the involvement of the fungus Geomyces destructans in WNS, but an identical fungus was recently isolated in France from a bat that was evidently healthy. The fungus has been recovered sparsely despite plentiful availability of afflicted animals.Methodology/Principal FindingsWe have investigated 100 bat and environmental samples from eight affected sites in 2008. Our findings provide strong evidence for an etiologic role of G. destructans in bat WNS. (i) Direct smears from bat snouts, Periodic Acid Schiff-stained tissue sections from infected tissues, and scanning electron micrographs of bat tissues all showed fungal structures similar to those of G. destructans. (ii) G. destructans DNA was directly amplified from infected bat tissues, (iii) Isolations of G. destructans in cultures from infected bat tissues showed 100% DNA match with the fungus present in positive tissue samples. (iv) RAPD patterns for all G. destructans cultures isolated from two sites were indistinguishable. (v) The fungal isolates showed psychrophilic growth. (vi) We identified in vitro proteolytic activities suggestive of known fungal pathogenic traits in G. destructans.Conclusions/SignificanceFurther studies are needed to understand whether G. destructans WNS is a symptom or a trigger for bat mass mortality. The availability of well-characterized G. destructans strains should promote an understanding of bat–fungus relationships, and should aid in the screening of biological and chemical control agents.