Genetics of the relB locus in Escherichia coli.Diderichsen, B; Fiil, N P; Lavallé, R
doi: N/Apmid: 326765
Genetics of the relB locus in Escherichia coli. B Diderichsen , N P Fiil and R Lavallé ABSTRACT A mutant of Escherichia coli with a delayed relaxed phenotype very similar to that of a previously described relB mutant has been obtained using a new selection procedure. The mutation giving rise to this phenotype has been shown to map at 34.5 min and to be 12% cotransducible with man. It is recessive, revertible, and most likely an allele of the relB gene. CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? « Previous | Next Article » Table of Contents This Article J. Bacteriol. July 1977 vol. 131 no. 1 30-33 » Abstract PDF Classifications Research Article Services Email this article to a colleague Similar articles in ASM journals Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of JB Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Load citing article information Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Diderichsen, B. Articles by Lavallé, R. Search for related content PubMed PubMed citation Articles by Diderichsen, B. Articles by Lavallé, R. Related Content Load related web page information Social Bookmarking CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? current issue January 2012, volume 194, issue 1 Alert me to new issues of JB About JB Subscribers Authors Reviewers Advertisers Inquiries from the Press Permissions & Commercial Reprints ASM Journals Public Access Policy JB RSS Feeds 1752 N Street N.W. • Washington DC 20036 202.737.3600 • 202.942.9355 fax • [email protected] Print ISSN: 0021-9193 Online ISSN: 1098-5530 Copyright © 2011 by the American Society for Microbiology. For an alternate route to JB .asm.org, visit: http://intl- JB .asm.org | More Info»
Control of Protein Synthesis in Escherichia coli: Analysis of an Energy Source Shift-DownJohnsen, Knud; Molin, Soren; Karlstrom, Olle; Maaloe, Ole
doi: N/Apmid: 326760
The energy source shift-down described in the preceding paper (Molin et al., J. Bacteriol. 131: 7–17, 1977) was used to study the effects of shift-down on protein synthesis. The overall rate of protein synthesis was reduced immediately, and to the same extent, in stringent and relaxed strains. The primary effect of the shift was a slowing down of the polypeptide chain growth rate, a finding not previously reported. In stringent strains the normal, preshift rate was reestablished within 2 to 3 min, whereas in relaxed strains the chain growth rate remained low for about 20 min before slowly returning to the normal value, which was reestablished some 50 to 60 min after the shift. Throughout this transition, the stability of messenger ribonucleic acid (mRNA) remained unchanged in both strains. We interpret these findings as evidence of the more rapid reduction of the mRNA pool in the stringent strain after shift-down: we believe that very soon after the shift, the stringent strain reduces its pool of mRNA and with it the number of ribosomes engaged in protein synthesis. In this manner the number of active ribosomes is adjusted to the availability of energy and carbon. The relaxed strain cannot rapidly reduce its mRNA pool, which thus remains large enough to engage a near-preshift number of ribosomes during a prolonged period; as a consequence its ribosomes must work at a reduced rate. The possibility that ppGpp is involved in the control of mRNA production is discussed. After shift-down, the initial part of ß-galactosidase (the auto- fragment) was produced at a higher rate than complete ß-galactosidase in the relaxed strain, as expected when translation is impeded. FOOTNOTES
Morphology and ultrastructure of Crenothrix polyspora Cohn.Völker, H; Schweisfurth, R; Hirsch, P
doi: N/Apmid: 873887
Morphology and ultrastructure of Crenothrix polyspora Cohn. H Völker , R Schweisfurth and P Hirsch ABSTRACT Naturally grown cell material of Crenothrix polyspora from the well of a waterworks was studied by means of phase-contrast and Nomarski interference microscopy as well as by transmission electron microscopy. The material consisted of clusters of sheathed filaments up to 2 cm long. Propagation forms observed were nonmotile, spherical cells that arose by simple ("macrogonidia") or multiple ("microgonidia") septation of the filamental tips. Ultrastructural analysis revealed Crenothrix to be procaryotic and gram negative, with several layers of sheath material surrounding the filaments. On thin sections, individual cells had elaborate membrane systems in the form of lamellar stacks. They resembled thylakoids of photosynthetic bacteria. Spectrophotometric analysis gave no indication of photosynthetic pigments. The cells also contained large hexagonal bodies, rod-shaped fibrillar elements, and polyphosphate granules. CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? « Previous | Next Article » Table of Contents This Article J. Bacteriol. July 1977 vol. 131 no. 1 306-313 » Abstract PDF Classifications Research Article Services Email this article to a colleague Similar articles in ASM journals Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of JB Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Load citing article information Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Völker, H. Articles by Hirsch, P. Search for related content PubMed PubMed citation Articles by Völker, H. Articles by Hirsch, P. Related Content Load related web page information Social Bookmarking CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? current issue January 2012, volume 194, issue 1 Alert me to new issues of JB About JB Subscribers Authors Reviewers Advertisers Inquiries from the Press Permissions & Commercial Reprints ASM Journals Public Access Policy JB RSS Feeds 1752 N Street N.W. • Washington DC 20036 202.737.3600 • 202.942.9355 fax • [email protected] Print ISSN: 0021-9193 Online ISSN: 1098-5530 Copyright © 2011 by the American Society for Microbiology. For an alternate route to JB .asm.org, visit: http://intl- JB .asm.org | More Info»