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J Pages

Publications and source records attributed to J Pages.

27 records · Page 2Linked to original sources
PubMed1973

Aspects of the encapsidation of simian virus 40 deoxyribonucleic acid.

Growing subcloned CV1-cells were infected with simian virus 40, and the time course of virus formation was determined. When infected cells were fractionated into cytoplasmic and nuclear fractions, most of the progeny virus particles were recovered in the cytoplasmic extract and not in the nuclei. This result was independent of the technique used for the preparation of nuclei and of the time after infection at which the extracts were prepared. Leakage of the virions from the nucleus occurred during the course of cell fractionation, suggesting that the nuclear membrane of the infected cells is damaged. Virions were found to accumulate in a nonlinear fashion, at the time when the number of viral deoxyribonucleic acid (DNA) molecules increases linearly with time after infection. This suggests that the size of the intracellular pool of capsid proteins increases constantly during the late phase of virus replication. Progeny viral DNA to become encapsidated is withdrawn at random from the pool of replicated DNA molecules.

Animals↗
PubMed1973

Replication of simian virus 40 deoxyribonucleic acid: analysis of the one-step growth cycle.

The time course of replication of simian virus 40 deoxyribonucleic acid (DNA) was investigated in growing monolayer cultures of subcloned CV1 cells. At multiplicities of infection of 30 to 60 plaque-forming units (PFU)/cell, first progeny DNA molecules (component 1) were detected by 10 hr after infection. During the following 10 to 12 hr, accumulation of virus DNA proceeded at ever increasing rates, albeit in a non-exponential fashion. The rate of synthesis then remained constant, until approximately the 40th hour postinfection, when DNA replication stopped. Under these conditions, the duration of the virus growth cycle was approximately 50 hr. The time needed for the synthesis of one DNA molecule was found to be approximately 15 min. At multiplicities of infection of 1 or less than 1 PFU/cell, the onset of the linear phase of DNA accumulation was delayed, but the final rate of DNA synthesis was the same, independent of the input multiplicity. This was taken as a proof that templates for the synthesis of viral DNA multiply in the cell during the early phase of replication. However, the probability for every replicated DNA molecule to become in turn replicative decreased constantly during that phase. This could be accounted for by assuming a limited number of replication sites in the infected cell.

Animals↗
PubMed1973

Relationship between replication of simian virus 40 DNA and specific events of the host cell cycle.

The relationship between replication of simian virus 40 (SV40) DNA and the various periods of the host-cell cycle was investigated in synchronized CV(1) cells. Cells synchronized through a double excess thymidine procedure were infected with SV40 at the beginning or the middle of S, or in G(2). The first viral progeny DNA molecules were in all instances detected approximately 20 h after release from the thymidine block, independent of the time of infection. The length of the early, prereplicative phase of the virus growth cycle therefore depended upon the period of the cell cycle at which the cells were infected. Infection with SV40 was also performed on cells obtained in early G(1) through selective detachment of cells in metaphase. As long as the cells were in G(1) at the time of infection, the first viral progeny DNA molecules were detected during the S period immediately following, whereas if infection took place once the cells had entered S, no progeny DNA molecule could be detected until the S period of the next cell cycle. These results suggest that the infected cell has to pass through a critical stage situated in late G(1) or early S before SV40 DNA replication can eventually be initiated.

Animals↗
PubMedDate not supplied

[Diagnosis of extraintestinal amebiasis by an indirect ELISA method].

Immunoglobulins G and M, parenchymal lysis witness, are searched by Indirect ELISA technique. This methodology, epidemiologic studies applied, presents with reference technique: Indirect Hemagglutination a good correlation (r = 0.93). Other qualities are big specificity and good reproducibility .

Amebiasis↗
PubMedDate not supplied

[Multiple expressions of mouse peritoneal cell immune potential].

Peritoneal cells (PC) from unstimulated mice are able to form a high number of rosettes (RFC) (20 to 50%) with sheep red blood cells (SRBC) or bromelin treated isologous mouse red blood cells (MRBC(b)). In culture, this population develops a high number of plaque forming cells (PFC) against SRBC and MRBC(b) with a maximum at day 3-4, while the number of RFC decreases in such a way that the total number of RFC + PFC remains constant. The significance of such results is discussed. Evidence is provided, by the use of radioactive labelling, that IgM antibodies and different sub-classes of IgG are synthesized in vitro by PC during culture.

Animals↗