Skip to main content
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1982 Apr;150(1):239–244. doi: 10.1128/jb.150.1.239-244.1982

Electrical nature of the taxis signal in cyanobacteria.

G V Murvanidze, A N Glagolev
PMCID: PMC220105  PMID: 6801020

Abstract

Electrical events after a light-dark stimulus were studied in the multicellular organism Phormidium uncinatum. Normally, such a stimulus causes the gliding trichome to reverse direction. By directing a large light spot on the end of a batch of trichomes and then switching it off, we achieved synchronization of the trichomes, since the "head" is much more sensitive than the "tail." The abrupt disappearance of a uniform light produced a depolarization wave which initiated at the head, as registered by externally applied electrodes. The second stimulus produced a depolarization of the opposite direction, reflecting the reorientation of the trichomes. No electrical response was observed at Ca2+ concentrations less than or equal to 10(-8) M. Factors causing oscillatory reversals, i.e., a combination of Ca2+ and A23187, or a viscous environment also abolished the electrical signal. Changes in an externally applied electrical field (4 V/cm2) had little effect on the motile behavior of P. uncinatum or Oscillatoria princeps. However, in the presence of 5 microM Ca2+-1 microM A23187, all the trichomes reversed synchronously to the anode after a change in polarity of an externally applied electrical field. We suggest that an increased Ca2+ concentration together with a change in delta psi (or delta mu H+) represents the taxis signal in cyanobacteria.

Full text

PDF

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adler J. Chemotaxis in bacteria. Annu Rev Biochem. 1975;44:341–356. doi: 10.1146/annurev.bi.44.070175.002013. [DOI] [PubMed] [Google Scholar]
  2. Häder D. P. Influence of electric fields on photophobic reactions in blue-green algae. Arch Microbiol. 1977 Jul 26;114(1):83–86. doi: 10.1007/BF00429635. [DOI] [PubMed] [Google Scholar]
  3. Khan S., Macnab R. M. The steady-state counterclockwise/clockwise ratio of bacterial flagellar motors is regulated by protonmotive force. J Mol Biol. 1980 Apr 15;138(3):563–597. doi: 10.1016/s0022-2836(80)80018-0. [DOI] [PubMed] [Google Scholar]
  4. Krieg N. R., Tomelty J. P., Wells J. S., Jr Inhibitio of flagellar coordination in Spirillum volutans. J Bacteriol. 1967 Nov;94(5):1431–1436. doi: 10.1128/jb.94.5.1431-1436.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Macnab R. M., Ornston M. K. Normal-to-curly flagellar transitions and their role in bacterial tumbling. Stabilization of an alternative quaternary structure by mechanical force. J Mol Biol. 1977 May 5;112(1):1–30. doi: 10.1016/s0022-2836(77)80153-8. [DOI] [PubMed] [Google Scholar]
  6. Miller J. B., Koshland D. E., Jr Membrane fluidity and chemotaxis: effects of temperature and membrane lipid composition on the swimming behavior of Salmonella typhimurium and Escherichia coli. J Mol Biol. 1977 Apr;111(2):183–201. doi: 10.1016/s0022-2836(77)80122-8. [DOI] [PubMed] [Google Scholar]
  7. Ordal G. W. Calcium ion regulates chemotactic behaviour in bacteria. Nature. 1977 Nov 3;270(5632):66–67. doi: 10.1038/270066a0. [DOI] [PubMed] [Google Scholar]
  8. Szmelcman S., Adler J. Change in membrane potential during bacterial chemotaxis. Proc Natl Acad Sci U S A. 1976 Dec;73(12):4387–4391. doi: 10.1073/pnas.73.12.4387. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES