Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.8 (hypoxanthine-guanine phosphoribosyltransferase)
 2,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mutagenicity of N-nitrosobis(2-oxopropyl)amine was measured in the V79 assay using homogenates of acinar cells and duct tissue from the pancreases of Syrian hamsters and MRC-Wistar rats as the activating systems. Mutations at the sodium/potassium ATPase and hypoxanthine:guanine phosphoribosyltransferase loci were measured by resistance to ouabain and 6-thioguanine (TG). The order of effectiveness in generating mutagens from BOP was hamster duct, hamster acinar, rat duct, rat acinar. These data show extensive differences in BOP activation by hamster acinar and duct tissue.
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PMID:The mutation of V79 cells by N-nitrosobis(2-oxopropyl)amine activated by pancreas acinar and duct tissue from Syrian hamsters and MRC-Wistar rats. 215 24

The effects of Mycoplasma pneumoniae on host cell metabolism were studied by using two types of host cells, MRC-5 human lung fibroblasts, a normal cell line, and Lesch-Nyhan fibroblasts, a cell line deficient in hypoxanthine-guanine phosphoribosyl transferase (EC 2.4.2.8). The susceptibilities of the two cell types were determined by infecting the cells with M. pneumoniae at different multiplicities of infection (MOI). Our data indicate that the Lesch-Nyhan cells were four times more susceptible to damage by M. pneumoniae than the MRC-5 cells. The effects of different MOIs (10 and 50) on de novo purine synthesis. DNA synthesis, and the development of a cytopathic effect were determined. In both cell types, the higher MOI inhibited de novo purine synthesis to a greater extent than the lower MOI. This correlated closely with the cytopathic effect which developed in the monolayers (i.e., the more the inhibition of de novo purine synthesis, the greater the cytopathic effect which developed). In the Lesch-Nyhan cells, DNA synthesis was completely inhibited by the high MOI, whereas in the MRC-5 cells, DNA synthesis was stimulated by the high MOI. In the MRC-5 cells infected with M. pneumoniae, purine salvage activity increased, as indicated by an increase in adenosine deaminase (EC 3.5.4.4) activity. These data indicate that M. pneumoniae alters host cell metabolism, particularly the nucleic acid metabolic pathways. This may explain in part the mechanism of pathogenesis of M. pneumoniae infection.
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PMID:De novo purine synthesis, purine salvage, and DNA synthesis in normal and Lesch-Nyhan fibroblasts infected with Mycoplasma pneumoniae. 640 90

Human diploid fibroblasts, strain MRC-5, were permeabilized by electroporation and treated with 5-methyl deoxycytidine triphosphate (5-methyl dCTP) in the S phase of the cell cycle. The frequency of TGR HPRT- cells was increased up to 20-fold in comparison to control untreated cultures. Representative TGR clones were unable to grow in HAT, and these were treated with 5-azacytidine (5-aza-CR). In many cases subsequent growth in HAT medium was observed, but in others it is likely that the cells had run out of growth potential. The results provide the first evidence of the silencing and reactivation of a gene in normal diploid mammalian cells.
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PMID:Evidence for gene silencing by DNA methylation in normal human diploid fibroblasts. 748 35