Observations on the mechanism of copper damage in chlorella

Addition of excess copper to nongrowing cells of a normal, green Chlorella caused a reduction in total pigments and a blue shift of chlorophyll absorption, concurrent with the inhibition of photosynthesis. Chlorophylless yellow and white mutant strains of the same alga showed a rise in nonspecific absorption (i.e., change in light scatter) within 5 to 10 minutes after the addition of CuSO(4); concomitantly a lowering of packed cell volume and a rise in respiration occurred. Glutathione prevented all copper-induced changes, whereas MnCl(2) protected only partially. Selective inhibition of some responses to copper was observed when O(2) was absent or an antioxidant present.