CHEMOTAXIS TOWARDS SUGARS IN CHLAMYDOMONAS-REINHARDTII

Chemotaxis of Chlamydomonas reinhardtii 137c cells towards maltose and sucrose was observed by capillary assay. The threshold concentration was approximately 10(-5) M for maltose and 10(-3) M for sucrose. The p eak accumulation of cells occurred at 10(-3) M for maltose and 10(-2) M for sucrose. A selection procedure for chemotaxis mutants was develo ped. Mutant strain CHE-1 was not attracted by maltose; mutant strain C HE-2 was not attracted by sucrose. Addition of attractant fully inhibi ted photoaccumulation of cells. After a period of time the photorespon se of cells recovered. Under the conditions of our experiments the per iod of adaptation lasted 15-20 min in wild-type cells and 4-5 min in m utant cells on the given sugar. Glucose and acetate did not attract ce lls of Chlamydomonas. Added to the medium, these compounds had no effe ct on the photoaccumulation of cells.