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S R Tronick

Publications and source records attributed to S R Tronick.

104 records · Page 6Linked to original sources
PubMed1974

Immunological properties of two polypeptides of Mason-Pfizer monkey virus.

Two polypeptides were isolated from the Mason-Pfizer monkey virus (MP-MV). The polypeptides, designated MP-MV p26 and MP-MV p15, were 26,000 and 15,000 molecular weight, respectively, based on gel filtration chromatography in the presence of 6 M guanidine hydrochloride. Radioimmunoassays developed for MP-MV p26 and p15 were, respectively, 10 and 100 times more sensitive than immunodiffusion and 1 and 10 times more sensitive than micro-complement fixation for the detection of MP-MV. Antigens of other reverse transcriptase-containing RNA viruses did not cross-react in either MP-MV radioimmunoassay. Further, antisera against these other viruses did not react with the radioiodine-labeled MP-MV polypeptides. The MP-MV radioimmunoassays should be useful in studying the natural occurrence of this virus and its relationship to primate tumors.

Animals↗
PubMed1974

Temperature-sensitive mutants of murine leukemia virus. IV. Further physiological characterization and evidence for genetic recombination.

Several temperature-sensitive mutants of the Rauscher strain of murine leukemia virus representing three distinct physiological groups have been further characterized. Genetic recombination between different pairs of these mutants has been demonstrated. Several representative genetic recombinants were isolated and shown to replicate equally well at the permissive (31 C) and nonpermissive (38 C) temperatures and to have serological characteristics of the wild-type parental virus. Alternative models for the mechanisms involved in recombination between type C RNA viruses are discussed.

Animals↗
PubMed1973

Comparative biochemical and immunological studies of bacterial glutamine synthetases.

Antisera prepared against adenylylated and unadenylylated Escherichia coli glutamine synthetase cross-reacted with the glutamine synthetases from a number of gram-negative bacteria and one gram-variable species as demonstrated by immunodiffusion and inhibition of enzyme activity. In contrast, the antisera did not cross-react with the glutamine synthetases from gram-positive bacteria (with one exception) nor with the synthetases of higher organisms. Modification of the various glutamine synthetases by covalent attachment of adenosine 5'-monophosphate (or other nucleotides) was tested for by determining whether or not snake venom phosphodiesterase altered catalytic activity in a manner similar to its effect on adenylylated E. coli glutamine synthetase. Only the activity of the glutamine synthetases from gram-negative bacteria grown with specific levels of nitrogen sources could be altered by snake venom phosphodiesterase. In addition, a relative order of antigenic homology between cross-reacting enzymes was suggested based on the patterns of spur formation in the immunodiffusion assay.

Adenine Nucleotides↗
PubMed1971

Methylation of the flagellin of Salmonella typhimurium.

The methylation of endogenous proteins by Salmonella typhimurium SL 870 was investigated in cell-free extracts by using S-adenosylmethionine as methyl donor. Several lines of evidence are presented which suggest that one of the methylated products is the protein flagellin. Mutant strains of SL 870 (nml(-)fla(+) and nml(+)fla(-)) were also found to synthesize epsilon-N-methyl-lysine. It is proposed that S. typhimurium possesses at least two genes specifying different methylating enzymes. One gene product is a flagellin-specific methylating enzyme, whereas the other gene(s) codes for enzymes that methylate one or more other cell proteins.

Acrylates↗
PubMedDate not supplied

Nucleotide sequence evidence for relationship of AIDS retrovirus to lentiviruses.

Lentiviruses are a subfamily of retroviruses which have been aetiologically linked to the induction of arthritis, encephalitis, progressive pneumonia and slow neurological diseases in certain species. Relatively little is known about their genome structure, mechanisms of pathogenesis or evolutionary relationships with other retroviral subfamilies. In an effort to understand better the mechanisms by which these viruses induce such a variety of chronic diseases, we have molecularly cloned and physically characterized the genomes of caprine arthritis-encephalitis virus (CAEV) and equine infectious anaemia virus (EIAV) (A.Y. et al., in preparation). The latter, which bears some morphological similarity to the lentiviruses, has yet to be classified definitively as one. Here, we have determined the nucleotide sequence of a highly conserved region within the CAEV and EIAV pol genes. We demonstrate a much closer relationship of their predicted pol gene products to that of the presumed aetiological agent of human acquired immune deficiency syndrome (AIDS) than to those of other retroviruses. Additional pairwise comparisons allowed us to generate an evolutionary tree showing that the pol genes of lentiviruses and oncoviruses have evolved from a common progenitor.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

fgr proto-oncogene mRNA induced in B lymphocytes by Epstein-Barr virus infection.

Several acute transforming retroviruses encode tyrosine-specific protein kinases which possess structural and functional relationships to cell-surface receptors for certain growth factors. One such tyrosine kinase is encoded by the onc gene, v-fgr, of Gardner-Rasheed feline sarcoma virus (GR-FeSV). Recently, we have isolated and characterized the human gene, c-fgr, corresponding to the viral onc sequence and have shown that c-fgr is a unique gene located on the short arm of chromosome 1 (ref. 7). Here we report that certain lymphomas (but not sarcomas or carcinomas) express fgr-related messenger RNA. This transcript is detected in Burkitt's lymphoma cell lines naturally infected with Epstein-Barr virus (EBV), but not in EBV-negative Burkitt's lymphoma cells. Normal umbilical cord or peripheral blood lymphocyte lines established in vitro by EBV infection also contain detectable c-fgr mRNA. Moreover, a 50-fold increase of the steady-state c-fgr mRNA concentration is observed when uninfected Burkitt's lymphoma cell lines are deliberately infected with EBV. These findings demonstrate for the first time the induction of a proto-oncogene in response to infection by a DNA tumour virus.

B-Lymphocytes↗