Cytoplasmic free-Ca2+ level rises with repellents and falls with attractants in Escherichia coli chemotaxis.
Cytoplasmic free-Ca2+ levels in Escherichia coli were measured by use of the fluorescent Ca(2+)-indicator dye fura-2. Chemotactically wild-type E. coli regulated cytoplasmic free Ca2+ at approximately 100 nM when no stimuli were encountered, but changes in bacterial behavior correlated with changes in cytoplasmic free-Ca2+ concentration. For chemotactically wild-type E. coli, addition of a repellent resulted in cells tumbling and a transient increase in cytoplasmic free-Ca2+ levels. Conversely, addition of an attractant to wild-type cells caused running and produced a transient decrease in cytoplasmic free-Ca2+ levels. Studies with mutant strains showed that the chemoreceptors were required for the observed changes in cytoplasmic free-Ca2+ levels in response to chemical stimuli.
D000596:Amino Acids / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism*; D018274:Electroporation; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D016257:Fura-2; D009154:Mutation; D011956:Receptors, Cell Surface / Q000172:deficiency; D013050:Spectrometry, Fluorescence
D000596:Amino Acids; D011956:Receptors, Cell Surface; D002118:Calcium; D016257:Fura-2