title: Chemotactic responses of Chlamydomonas reinhardtii.
abstract: A capillary chemotaxis assay revealed that among a wide range of inorganic and organic chemicals, only ammonium ion (NH4+) could serve as an attractant of Chlamydomonas reinhardtii. NH4+ (10(-2) M) gave the maximum response, with up to a 15-fold increase in accumulated algae being measured. No repellents for the chlorophyte were detected. The response to NH4+ was influenced by exogenous levels of calcium, but not by L-methionine. The optimal pH for positive chemotaxis was 7.0; however, attraction was measurable from pH 4.0 to 9.0. Positive chemotaxis was stimulated by performing the assay under fluorescent illumination rather than in the dark.
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002633:Chemotaxis; D002696:Chlamydomonas / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008715:Methionine / Q000494:pharmacology
chemical_list: D000643:Ammonium Chloride; D008715:Methionine; D002118:Calcium