- Volume 43, Issue 2, 1979

The virus-specific nucleotide sequences in the RNA and DNA of a Kirsten mouse sarcoma virus (Ki-MSV)-transformed non-producer human osteosarcoma cell clone and two subclones of these cells that reverted to a normal phenotype have been analysed by hybridization of sarcoma virus-specific complementary DNA (cDNA) to cellular RNA or DNA. Whereas the transformed clone had acquired de novo Ki-MSV sequences in the RNA and DNA of the cells, both the revertant cell lines seemed to have lost most or all of this information from the cellular nucleic acids. The DNA from the revertant cells lacked the sequences represented either in the Ki-MSV-specific cDNA or in the total cDNA of the leukaemia-sarcoma virus complex. Thus, the reversion of the virus-transformed human cells to normal morphology is associated with the loss of most or all of the proviral sequences from the cellular DNA.

A novel aggregation form of particles of a pea isolate of broad bean wilt (BBWV) is described. The aggregates consist of hollow tubules that are square or rectangular in section (quadrangular tubules) and have walls made up of two parallel rows of virions. These aggregates, which may be specific for the virus strain under study, occur in the same tissues as the cylindrical virus tubules typically induced by many other strains of BBWV.

Interferon production was inhibited in the Namalwa line of human lymphoblastoid cells by treatment with 2-deoxy-d-glucose or d-glucosamine. d-Glucosamine also inhibited protein synthesis and the cells were no longer viable, whereas 2-deoxy-d-glucose allowed protein and RNA synthesis to continue at control rates, and the cells remained fully viable. It is concluded that a glycosylation step is essential for production of lymphoblastoid interferon.

Simian rotavirus (SA-11) isolated from infected African green monkey kidney cells was separated into two virus fractions in a CsCl density gradient and their proteins analysed on a continuous phosphate buffered polyacrylamide gel electrophoresis system. One peak (buoyant density 1.37 g/ml) contained double capsid virus particles which were radioimmunoassay (RIA)- and haemagglutinin (HA)-positive and yielded eight polypeptides whose mol. wt. ranged from 48000 to 128000. The second peak (buoyant density 1.39 g/ml) which contained 70% single capsid particles and was RIA-positive but HA-negative, yielded only five polypeptides. The three polypeptides missing in the second peak are associated presumably with the outer capsid of SA-11 virus particles and one or more of these is assumed to be the HA of SA-11 rotavirus.

Infection of cell cultures with herpes simplex virus type 1 (HSV-1) under standard culture conditions yielded persistently infected cells capable of continued growth in the presence of virus and of forming colonies in agarose. The ability of an infected culture to yield cells able to survive HSV-1 infection was directly related to the presence of S phase cells (cells actively engaged in DNA synthesis) at the time of infection. Only when very high multiplicities of infecting virus (> 10) were used did cultures fail to yield persistently infected cells capable of colonial growth in agarose. Cell clones derived from colonies grown in agarose established cell cultures which possessed all the characteristics of HSV-1 persistently infected cultures. When cultures were cloned a second time in agarose, as a rare event, cell cultures which did not immediately liberate infectious virus could be isolated. These cell cultures, however, possessed an increased resistance to superinfection by HSV-1. On continued cultivation they reverted to persistence as exhibited by the sudden onset of virus cytopathic effects and release of infectious virus.