Factors affecting the intracellular parasitic growth of Bdellovibrio bacteriovorus developing within Escherichia coli.

  • Seidler R
  • Starr M
  • 19

    Readers

    Mendeley users who have this article in their library.
  • 44

    Citations

    Citations of this article.

Abstract

A procedure for one-step growth experiments on Bdellovibrio bacteriovorus growing parasitically in Escherichia coli B was developed. The resulting one-step growth curves showed that, under defined conditions at 30 C, each singly infected E. coli host cell, on the average, gave rise to 5.7 Bdellovibrio cells. This value was confirmed by single-burst experiments and by microscopic observations. In the temperature range of 25 to 38 C, the average burst size and the duration of the latent period were inversely proportional to the temperature. The effect of hydrogen ion concentration on the one-step growth kinetics in this system indicated a broad pH optimum, ranging from neutrality to slightly alkaline pH values. After Bdellovibrio cells and host cells were mixed, there was always a delay (the so-called "lag phase") before the parasite titer increased in terms of plaque-forming units. Phase-contrast microscopic observations indicated that this delay stems in part from the polyphasic nature of the Bdellovibrio life cycle. We propose the following five terms to make explicit the sequence of events in this life cycle: "attachment," "penetration," "elongation," "fragmentation," and "burst." Nutritional experiments revealed that Bdellovibrio obtains a major fraction of its cellular components from host-cell material. Infection of E. coli by Bdellovibrio without added Mg(++) or Ca(++) (0.003 m Mg(++), 0.002 m Ca(++)) resulted in partial or total lysis of the host cell soon after infection. Protoplast integrity was necessary for the normal completion of the intracellular growth phase of Bdellovibrio in E. coli; normal development of the parasite took place only in the presence of Mg(++) or Ca(++).

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

  • PMID: 4886299
  • PUI: 89070146
  • SGR: 0014470841
  • SCOPUS: 2-s2.0-0014470841
  • ISSN: 00219193

Authors

  • R. J. Seidler

  • M. P. Starr

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free