CYTOPATHOGENIC MYCOPLASMAS ASSOCIATED WITH TWO HUMAN TUMORS. I. ISOLATION AND BIOLOGICAL ASPECTS

CYTOPATHOGENIC MYCOPLASMAS ASSOCIATED WITH TWO HUMAN TUMORS. II. MORPHOLOGICAL ASPECTS

Hummeler, K. (The Children's Hospital of Philadelphia, Philadelphia, Pa.), D. Armstrong, and N. Tomassini. Cytopathogenic mycoplasmas associated with two human tumors. II. Morphological aspects. J. Bacteriol. 90:511-516. 1965.-Cytopathic effects (CPE) produced in HeLa cell cultures by two strains of mycoplasmas (F-11 and F-12) were studied by light and electron microscopy. CPE, which was marked by cytoplasmic vacuolization, did not appear to depend on intracellular mycoplasma infection. The cytopathogenic mycoplasmas appeared to be similar, both morphologically and in their intra- and extracellular distribution, to noncytopathogenic mycoplasmas previously studied by others. The probability that the CPE is related to depletion of essential nutrients is discussed, and the fine structure of the mycoplasmas is described.

Biological and physical properties of the suckling mouse cataract agent grown in chicken embryos

Experiments were carried out with the suckling mouse cataract agent (SMCA) in an attempt to better characterize the nature of this agent. Despite the fact that high titers of SMCA were found in the chorioallantoic fluid of inoculated chicken embryos, the agent did not replicate in chicken embryo epithelial cell cultures. SMCA did not interfere with Sindbis virus plaque formation and was not inhibited by chicken interferon or polyinosinic-polycytidylic acid. The agent was relatively resistant to high pH and osmotic shock but was inactivated by low pH. Electron micrographs of negatively stained particles concentrated and semipurified from infected chicken embryo chorioallantoic fluids revealed pleomorphic particles ranging from approximately 70 to 400 nm in diameter. SMCA was resistant to kanamycin, novobiocin, and sodium aurothiomalate.

Mycoplasmas and cell cultures

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New assay procedure for separation of mycoplasmas from virus pools and tissue culture systems

Presence of mycoplasma organisms in tissue culture systems and virus pools was detected by titration of the contaminated material on agarose-suspended BHK21/13S cells. The use of this method permitted isolation of mycoplasmas which could not be detected by standard assay methods. Mycoplasma colonies at concentrations ranging from 10(4) to 10(6) colony-forming units/ml in agarose-BHK21/13S media could be distinguished from virus plaques, and the two populations of microorganisms could be easily disassociated either by electron microscopy or by biological methods. All isolated mycoplasmas were identified in growth inhibition tests as belonging to the GDL group. The growth inhibition test on agarose-BHK21/13S cell suspension plates could also be applied directly to those strains which could not be isolated by standard assay procedures.

The interaction of mycoplasmas with mammalian cells. I. HeLa cells, neutrophils, and eosinophils

The ultrastructure of three mycoplasma species, Mycoplasma pneumoniae, Mycoplasma gallisepticum, and Mycoplasma neurolyticum, has been studied in isolated form as well as in HeLa cell cultures and following incubation with human peripheral blood leukocytes. During log growth phase, the organisms could be distinguished from each other on the basis of their fine structure. In mammalian cell cultures, PPLO's appeared to proliferate on the plasma membranes which had markedly increased their surface area by means of long cytoplasmic processes which extended toward and surrounded them. Some of the microorganisms affected in this way may well have lain, not in vacuoles, but at the bottom of crypts. It is suggested that the cytopathogenic effect exerted by PPLO's on some tissue cultures may be attributable to membrane damage. Mycoplasmas adhered to leukocyte plasma membranes in a similar manner. They were avidly phagocytosed by neutrophils and eosinophils with accompanying degranulation of the white cells. It is thus likely that the local inflammatory reaction induced by PPLO's does not differ in essence from that caused by bacteria.

Genetic Differentiation by Nucleic Acid Homology II. Genotypic Variations Within Two Mycoplasma Species

Somerson, Norman L. (National Institutes of Health, Bethesda, Md.), Paul R. Reich, Barbara E. Walls, Robert M. Chanock, and Sherman M. Weissman. Genetic differentiation by nucleic acid homology. II. Genotypic variations within two Mycoplasma species. J. Bacteriol. 92:311-317. 1966.-A deoxyribonucleic-ribonucleic acid (DNA-RNA) homology technique was used to determine genetic relatedness among the nucleic acids of eight mycoplasmas which were serologically classified as Mycoplasma hominis type 1. The DNA preparations from these organisms were each found to be distinct. No subgrouping of the M. hominis type 1 strains could be demonstrated. In contrast, when the nucleic acids from six serologically related mycoplasmas which were isolated from tissue cultures were studied, the DNA from these species could not be distinguished. The DNA buoyant densities of the tissue culture isolates were similar. These isolates were closely related genetically to a porcine mycoplasma, M. hyorhinis.

Effect of mycoplasma on interferon production and interferon assay in cell cultures

Armstrong, D. (The Children's Hospital of Philadelphia, Philadelphia, Pa.), and K. Paucker. Effect of mycoplasma on interferon production and interferon assay in cell cultures. J. Bacteriol. 92:97-101. 1966.-The influence of mycoplasma on the production and action of interferon was studied in cultures of both L and human embryonic kidney (HEK) cells. Mycoplasma hominis 1, the Negroni agent, and the F12 mycoplasma were used for infection of L cells, and M. hominis 1 and M. pneumoniae for inoculation of HEK cells. All strains were capable of multiplication in the culture systems employed. None produced detectable levels of interferon, and responsiveness of the cells to induction of interferon by virus remained unaltered. Infection with mycoplasma did not impair the sensitivity of the cells to the action of interferon, nor was the replication of vesicular stomatitis virus noticeably diminished.

Compraison of mycoplasmas associated with human tumors, leukemia, and tissue cultures

Leach, R. H. (Wellcome Research Laboratories, Beckenham, Kent, England), and M. Butler. Comparison of mycoplasmas associated with human tumors, leukemia, and tissue cultures. J. Bacteriol. 91:934-941. 1966.-Mycoplasmas originally isolated by various workers from tissue cultures prepared from or inoculated with tumor or leukemic cells fell into four groups; each related to existing species or serotypes. These were Mycoplasma pulmonis, M. fermentans, M. hominis, and the GDL serotype, the last two being well known as contaminants of uninoculated cell lines. All the test strains were able to grow well in certain tissue cultures, and some caused cytopathic effects and acidity. These observations are discussed in terms of the relationship of these strains to the malignant tissues with which they were originally associated. The variable results obtained in certain biological tests on these strains emphasized the need for standardization of the conditions under which such tests may be employed to assist in identification of Mycoplasma species.

Genetic relatedness among mycoplasmas as determined by nucleic acid homology

Reich, Paul R. (National Institutes of Health, Bethesda, Md.), Norman L. Somerson, James A. Rose, and Sherman M. Weissman. Genetic relatedness among mycoplasmas as determined by nucleic acid homology. J. Bacteriol. 91:153-160. 1966.-A sensitive membrane filter method to detect nucleic acid homology was used to determine genetic relatedness among mycoplasma isolates. Deoxyribonucleic acid (DNA) was isolated from mycoplasmas and used as a primer for synthesis of tritium-labeled, complementary ribonucleic acid (RNA) by the enzyme RNA polymerase. DNA from each mycoplasma isolate tested was reacted separately with complementary RNA synthesized with homologous or heterologous DNA as primer. The quantity of DNA-RNA hybrids formed was assayed by the nitrocellulose membrane filter method. The amount of radioactivity bound to the membrane filter was used to measure the degree of homology between the nucleic acids. The three mycoplasma isolates from human oral cavities (DC 63, V2785, Botteicher) and the prototype strain PG21 placed in the Mycoplasma hominis type 1 group by gel diffusion and complement-fixation testing were investigated with this technique. Analysis of the data confirmed their immunological grouping with the M. hominis type 1 and their distinction from other human mycoplasmas. In contrast to the data from immunological studies, none of the four isolates tested appeared to be identical to any other. Preliminary experiments with DNA from four other mycoplasma isolates from tissue cultures inoculated with human material revealed them to be closely related, and possibly identical. The advantages of this nucleic acid homology technique for the study of relatedness among mycoplasmas are described.