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Biomedical subjects

M POLLARD

Publications and source records attributed to M POLLARD.

At least 19 recordsLinked to original sources
PubMed1964

ELECTRON MICROSCOPY OF LATENT PSITTACOSIS VIRUS IN MCCOY CELLS.

Kajima, Masahiro (University of Notre Dame, Notre Dame, Ind.), Nehama Sharon, and Morris Pollard. Electron microscopy of latent psittacosis virus in McCoy cells. J. Bacteriol. 88:709-715. 1964.-Replication of psittacosis virus in McCoy cells was observed periodically by electron microscopy, and was correlated with the appearance of inclusion bodies in infected cells stained by acridine orange fluorochrome. Three well-defined morphological stages characterized the replication cycle: (i) noninfectious initial body, (ii) noninfectious intermediate body, and (iii) infectious mature or elementary body. When replication of virus was interrupted by aminopterin, the virus failed to develop beyond the noninfective initial body stage; however, after treatment of such cultures with folinic acid, intermediate and mature virus particles appeared in the cells. Latent psittacosis virus, as described here, represented a virus in which the replication process was interrupted at a noninfective (eclipse) stage of the developmental cycle.

Acridines↗
PubMed1963

PSITTACOSIS-INFECTED CELL SYSTEM FOR STUDIES ON RADIATION DAMAGE.

Sharon, Nehama (University of Notre Dame, Notre Dame, Ind.), Morris Pollard, and W. R. Klemm. Psittacosis-infected cell system for studies on radiation damage. J. Bacteriol. 86:1139-1144. 1963.-The unique replication pattern of the agent of psittacosis in cells provides a means for studying biological effects of radiation and the influence of radioprotective drugs on this cell virus system. Intracellular psittacosis virus (strain TT) showed a distinctive sensitivity to X irradiation at 3 to 9 hr after onset of infection. This sensitivity to X rays disappeared later in the replication cycle when the virus-orientated ribonucleic acid matrix appeared in the infected cell. The effect of X rays was on the early stages of the virus, since evidence of subsequent developmental stages could not be observed. During the sensitive stage, the amount of surviving virus was related to the dose of X rays. Irradiation caused an irreversible reaction on sensitive virus. The progeny of surviving virus were unaltered in susceptibility to X rays. Addition of glutathione to infected cultures before irradiation increased the amount of surviving virus. Cysteine.HCl and heat-inactivated calf serum were only protective to the virus. Cysteamine was toxic to the cells, and low concentrations gave no protection. Other compounds tested failed to protect the viral agent against the effect of X rays.

Animals↗
PubMed1962

Effect of p-fluorophenylalanine of psittacosis virus in tissue cultures.

Tanami, Yoh (University of Texas Medical Branch, Galveston) and Morris Pollard. Effect of p-fluorophenylalanine on psittacosis virus in tissue cultures. J. Bacteriol. 83:437-442. 1962.-The inhibitory effect of p-fluorophenylalanine (FPA) on maturation of psittacosis virus was investigated, with attention to the time sequence of viral protein synthesis. Extracellular virus particles were not inactivated by FPA at a concentration of 100 mug per ml, at which level it interfered with maturation of intracellular virus. When FPA was added to infected tissue cultures earlier than 15 hr after infection, intracellular virus maturation was suppressed. However, when FPA was added after 15 hr, infective virus was produced, which indicates that the synthesis of a FPA-sensitive virus precursor (presumably viral protein) had already occurred. A latent ("dormant") infection of psittacosis virus, established in a medium deficient in phenylalanine and tyrosine, was also investigated.

Chlamydia↗