Changes in buoyant density and cell size of Escherichia coli in response to osmotic shocks.

W. W. Baldwin, M. J. Sheu, Patrick Bankston, C. L. Woldringh

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The buoyant density of Escherichia coli was shown to be related to the osmolarity of the growth medium. This was true whether the osmolarity was adjusted with either NaCl or sucrose. When cells were grown at one osmolarity and shocked to another osmolarity, their buoyant density adjusted to nearly suit the new osmolarity. When cells were subjected to hyperosmotic shock, they became denser than expected. When cells were subjected to hypoosmotic shock they occasionally undershot the new projected density, but the undershoot was not as dramatic as the overshoot seen with hyperosmotic shocks. Shrinkage and swelling of the cells in response to osmotic shocks could account for the change in their buoyant density. The changes in cell size after osmotic shocks were measured by two independent methods. The first method measured cell size with a Coulter Counter, and the second method measured cell size by stereologic analysis of Nomarski light micrographs. Both methods gave qualitatively similar results and showed the cells to be flexible. The maximum swelling recorded was 23% of the original cell volume, while the maximum shrinkage observed was 33%.

Original languageEnglish
Pages (from-to)452-455
Number of pages4
JournalJournal of Bacteriology
Volume170
Issue number1
StatePublished - Jan 1988

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Osmotic Pressure
Cell Size
Osmolar Concentration
Escherichia coli
Shock
Sucrose
Light
Growth

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

Cite this

Changes in buoyant density and cell size of Escherichia coli in response to osmotic shocks. / Baldwin, W. W.; Sheu, M. J.; Bankston, Patrick; Woldringh, C. L.

In: Journal of Bacteriology, Vol. 170, No. 1, 01.1988, p. 452-455.

Research output: Contribution to journalArticle

Baldwin, W. W. ; Sheu, M. J. ; Bankston, Patrick ; Woldringh, C. L. / Changes in buoyant density and cell size of Escherichia coli in response to osmotic shocks. In: Journal of Bacteriology. 1988 ; Vol. 170, No. 1. pp. 452-455.
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