title: Synthesis of DNA, rRNA, and protein by Rickettsia prowazekii growing in untreated or gamma interferon-treated mouse L929 cells.
abstract: The syntheses of DNA, rRNA, and protein by Rickettsia prowazekii growing in mouse fibroblastic L929 cells were measured at various times after the addition of gamma interferon (IFN-gamma) to correlate the inhibition of a site of macromolecular synthesis with the established IFN-gamma-induced inhibition of rickettsial growth. A method was developed to measure the syntheses of DNA, rRNA, and protein by R. prowazekii during a 2-h pulse-labeling period while the rickettsiae were growing within cultured host cells that had intact macromolecular synthesis. This method involved incubation of the rickettsia-infected cells with a radioactive precursor (H3 32PO4 or Tran35S-label), purification of the rickettsiae, purification of rickettsial nucleic acids, and analysis of rickettsial nucleic acids and proteins by electrophoresis and autoradiography. A key feature of the method involved the use of calculated specific activities from a densitometric analysis of gels and autoradiograms, a procedure that made the data independent of rickettsial recovery. Rickettsial DNA and rRNA syntheses were both inhibited 12 h after the addition of IFN-gamma to infected cultures, whereas the synthesis of rickettsial proteins was not inhibited at this time. In contrast, at 20 h after the addition of IFN-gamma, rickettsial DNA, rRNA, and protein syntheses were all inhibited.
authors.affiliation: Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile 36688.
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: J
authors.initials: J
authors.lastname: Turco
authors.forename: H H
authors.initials: HH
authors.lastname: Winkler
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002478:Cells, Cultured; D002645:Chickens; D004269:DNA, Bacterial / Q000096:biosynthesis*; D005347:Fibroblasts / Q000382:microbiology; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D012283:Rickettsia prowazekii / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D007371:Interferon-gamma