Endotoxin from Mycoplasma mycoides

Lipoglycans from mycoplasmas

Lipoglycans , distinguishable from bacterial lipopolysaccharides, are associated with the cytoplasmic membranes of several genera of Mollicutes, namely Acholeplasma, Mycoplasma neurolyticum , Anaeroplasma , and Thermoplasma. Structurally, the lipoglycans are long heteropolysaccharides covalently linked to a lipid. The exact structures of three have been determined. Thermoplasma oligosaccharide is attached to a diglycerol tetraether ; A. granularum to a diacyl glycerol. The lipoglycan from A. axanthum is unique by its possession of glycerol phosphate and galactose phosphate side chains and the occurrence of fatty acids in N-acyl linkages. Only one molecular species of lipoglycan occurs in a given species. These lipoglycans possess a variety of biological activities. The terminal three sugar residues define their antigenic specificity; they attach to specific receptors on mammalian cells; they exhibit pyrogenicity in rabbits and clot Limulus lysate; they stimulate the production of IgM antibody both in vivo and in vitro; they modulate the immune response to T-cell dependent antigens; they exhibit immunosuppressive and immunostimulatory activities.

Experimental infection of goats, sheep and calves with the large colony type of Mycoplasma mycoides subsp. mycoides

Goats, sheep and calves were inoculated intravenously with strain Y3343 of the large colony type of Mycoplasma mycoides subsp. mycoides isolated from a goat with polyarthritis. The goats and sheep died of septicemia (one was killed in extremis) within eight days. The goats had leukopenia and granulocytopenia. Coagulopathy was indicated in some goats; the fibrinogen titer, prothrombin and partial thromboplastin times increased with the progress of disease and the number of platelets decreased dramatically in one goat. Goats and sheep had cellulitis at the site of inoculation, pleural hemorrhages, pneumonia, myocarditis, renal infarcts, glomerulitis, adrenal cortical necrosis, enteritis, focal splenic necrosis, polyarthritis and lymphadenitis. Vasculitis and thrombi were seen occasionally, suggesting that vascular changes, perhaps together with coagulopathy, had a role in pathogenesis. One of two experimental calves developed a slight fever, arthritis and minor inflammation of adrenal tissue. Calves seen less susceptible to the mycoplasma organism given intravenously than do goats or sheep.

Mycoplasma-associated induction of interferon in ovine leukocytes

A mycoplasmal species, Acholeplasma laidlawii, isolated as a contaminant from a fetal lamb kidney cell line, was shown to be associated with the induction of interferon in cultures of ovine peripheral blood leukocytes. Broth cultures of the mycoplasma induced between 20 and 230 U of interferon per ml in leukocytes from two adult ewes. The amount of interferon produced correlated with the inoculum size of mycoplasma. Interferon production was associated with replication of the mycoplasma in the leukocyte cultures. Interferon was not induced by sterile mycoplasmal broth, a cell-free filtrate of the mycoplasmal cultures, or heat-inactivated mycoplasmas. The antiviral substance was characterized as interferon by the usual criteria.

Toxic membrane fractions from Mycoplasma fermentans

A recent isolate of Mycoplasma fermentans (strain K10, from human leukemic bone marrow) induced a lethal toxicity syndrome in mice. High doses of both viable and inactivated cells were toxic when injected intraperitoneally. Whole lysates and membranes from osmotically shocked cells killed mice, but cytoplasm did not. When membranes were dissolved in detergents and reaggregated by dialysis in the presence of Mg(2+), the lipid-protein complex thus formed was toxic. Lipids extracted from membranes with chloroform-methanol did not kill mice. Protein-rich fractions (obtained by reaggregation plus acetone washes or ammonium sulfate precipitation of dissolved membranes) were also not toxic. No qualitative differences in proteins from three toxic isolates and three nontoxic laboratory strains of M. fermentans were detectable by polyacrylamide gel electrophoresis. The toxic factor contained in reaggregated membranes was heat-stable but sensitive to Pronase, trypsin, and lipase.

PRODUCTION AND BIOLOGICAL CHARACTERISTICS OF AN EXTRACELLULAR NEUROTOXIN FROM MYCOPLASMA NEUROLYTICUM

Tully, Joseph G. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.). Production and biological characteristics of an extracellular neurotoxin from Mycoplasma neurolyticum . J. Bacteriol. 88: 381–388. 1964.—Toxigenic strains of Mycoplasma neurolyticum were found to produce a potent extracellular neurotoxin for mice under a variety of cultural conditions. The observed biological characteristics of this toxin were quite similar to those originally described by Sabin. The toxin was again found to be readily inactivated by prolonged incubation and, when separated from Mycoplasma cells by filtration, possessed a greater heat resistance than whole cells. Young mice and rats were generally susceptible to neurotoxin, whereas most other experimental animals were resistant. Filtration results confirmed a minimal reproductive unit of 125 to 200 mμ for two neurotoxic Mycoplasma strains, with both cell-free filtrates reproducing the rolling disease syndrome in mice. Twice-washed Mycoplasma cells were also observed to be as neurotoxic as filtrates. Plate counting results revealed an intravenous ld 50 of approximately 3 × 10 8 washed cells for young mice.