Abstract
Alkylphenol ethoxylates are biodegraded to alkylphenols in the environment. The 4-t-octylphenol (4-t-OP) is found to show endocrine disrupting action with estrogen-like properties and to be severely toxic to aquatic organisms. We have studied whether 4-t-OP affects gametogenesis of Chlamydomonas reinhardtii cells seen after nitrogen-starvation.
The mating ratios of gametes cells at the early stages of gametogenesis were increased by addition of 4-t-OP at the concentrations of 10-11 to 10-9 M, but were significantly decreased by that above the concentration of 10-6 M. Thus, we analyzed the expression of gametogenesis-related genes (NIT1, NAR3, FUS1, MID, GAS28) during gametogenesis, in the range of 4-t-OP concentrations at which the mating was stimulated. Effects of 4-t-OP on the expression of these genes were dependent on the mating types, mt+ and mt-: some genes of mt- were expressed more intensely than those of mt+. These results suggest that 4-t-OP enhances the expression of gametogenesis-related genes sex-specifically.
