Affiliation:
1. Department of Microbiology, Michigan State University, East Lansing 48824.
Abstract
In earlier studies of genetic competence in Escherichia coli induced with calcium-containing buffers, a strong correlation was found between transformation efficiency and the formation of poly-beta-hydroxybutyrate/calcium polyphosphate (PHB/Ca2+/PPi) complexes in the plasma membranes. In this study, we replaced Ca2+ with one of a number of other cations--monovalent, divalent, and trivalent--and found significant numbers of transformants (transformation efficiency, > 10(5)/micrograms of pBR322 DNA) only when the cells had high levels of PHB/Ca2+/PPi and the medium contained at least one of the divalent cations Ca2+, Mn2+, Sr2+, or Mg2+. Cells with high levels of the complexes were not competent when the medium did not contain these cations, but the cations were also ineffectual when the cells had few complexes. Surprisingly, Mn, Sr, and Mg were not incorporated into the complexes in place of Ca. These results indicate that PHB/Ca2+/PPi complexes and the above-mentioned divalent cations each have essential but disparate roles in genetic competence. Moreover, the strong selectivity of PHB/PPi for Ca2+ suggests the binding sites in the complexes are ionophoretic.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference18 articles.
1. The polyphosphate kinase gene of E. coli: isolation and sequence of the ppk gene and membrane location of the protein;Akiyama M.;J. Biol. Chem.,1992
2. Adsorption of bacteriophages to adhesions between wall and membrane of Escherichia coli;Bayer M. E.;J. Virol.,1968
3. Phosphorus. An outline of its chemistry, biochemistry and technology;Corbridge D. E. C.;Stud. Inorg. Chem.,1985
4. Studies on transformation of Escherichia coli with plasmids;Hanahan D.;J. Mol. Biol.,1983
5. Hanahan D. 1987. Mechanisms of DNA transformation p. 1177-1183. In F. C. Neidhardt J. L. Ingraham K. B. Low B. Magasanik M. Schaechter and H. E. Umbarger (ed.) Escherichia coli and Salmonella typhimurium: cellular and molecular biology vol. 2. American Society for Microbiology Washington D.C.
Cited by
45 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献