Effect of benzimidazole and cobalt on free cystine levels of Chlamydomonas wild type and cell division mutant strains

Inclusion of benzimidazole or cobalt in the growth medium causes considerably increases in the free cystine levels of wild type and a cell division mutant strain of Chlamydomonas reinhardi. Homocystine levels are reduced slightly. Since benzimidazole and cobalt also markedly affect the expression of the mutation, it is suggested as a tentative hypothesis that this may be achieved via the rise in free cystine. Cysteine in the growth medium does not increase the internal free cystine or the expression of the mutation in a similar way to benzimidazole or cobalt.