Suppression of Rous Sarcoma Virus Growth in Tissue Cultures by Mycoplasma orale

Interaction of feline sarcoma virus (FeSV) and mycoplasma

A factor present in the supernatant of an established human glioma cell line U-251 MG strongly suppresses feline sarcoma virus (FeSV) focus forming activity on feline embryo fibroblasts. The factor was identified as mycoplasma arginini. The enriched mycoplasma fraction had no cytpathogenic effect on the glioma cells or on the embryonic feline indicator cells. An antiserum prepared against this strain of mycoplasma abolished the inhibition. The exact mechanism is not known but arginine depletion in the medium seems to be an important factor.

Mycoplasma-virus interrelationships in mouse tracheal organ cultures

The effects produced by single and mixed infections with Mycoplasma pulmonis and influenza A/PR-8 virus were studied in mouse tracheal organ cultures. M. pulmonis multiplied in the tracheal organ cultures, producing inhibition of ciliary activity and histologic tissue damage. The organism grew in close association with the cell membranes but did not appear to attach directly to the membranes or the cilia. Influenza A virus also replicated in tracheal organ cultures, producing ciliary inhibition and more extensive cytopathologic changes. Virus particles were seen by electron microscopy to attach to and cause clumping of the cilia. Simultaneous infection of the organ cultures with mycoplasma and virus resulted in more rapid inactivation of ciliary activity and greater tissue damage than occurred when the cultures were infected with only mycoplasma or virus. Presence of the virus appeared to have no effect on the growth of the mycoplasma; however, the mycoplasma partially interfered with virus replication.

Mycoplasmas and cell cultures

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Salmonella suppression by known populations of bacteria in flies

Survivorship of Salmonella typhimurium, Streptococcus faecalis, Proteus mirabilis, and Pseudomonas aeruginosa was studied in dibiotic and tribiotic interactions in vitro and in various regions of the digestive tract of the blow fly, Calliphora vicina. In dibiotic interactions, Salmonella typhimurium dominated Streptococcus faecalis and was dominated by P. mirabilis, but in neither case was it eliminated from the larval gut. In tribiotic interactions, there was synergic suppression and a definite trend toward elimination of Salmonella typhimurium from the gut. This trend approaches but does not match the total exclusion of S. typhimurium from the gut of maggots with a normal flora. Bacterial survival in the gut of the fly is discussed in relation to doubling time, sweep-out rate of the maggot and prepupal gut, and the midgut bactericide.

The development of feline cell lines for the growth of feline infectious enteritis (panleucopaenia) virus

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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.