Carotenoids of Wild Type and Mutant Strains of the Green Aiga, Chlamydomonas reinhardi

Abstract

Light-grown cultures of the wild type strain of C. reinhardi have been shown to contain the usual pigments of the Chloro-phyceae: [alpha]- and [beta]-carotene, luteln, vlolaxanthin, and neoxanthin. In addition, zeaxanthin, luteoxanthin, trollein, and a new carotene, P-460, which appears to be a cis-isomer of [gamma]-carotene, have also been identified. Dark-grown cultures of the wild type strain contain less total carotenold, and this decrease occurs exclusively in the xanthophyll fraction, resulting in a lower xanthophyll carotene ratio than that found in the light-grown cultures. The dark-grown cultures are also characterized by a lower [beta]-carotene/[alpha]-carotene ratio, and 2 xanthophylls, zeaxanthin and luteoxanthin, are absent. The mutant, y-2, when cultured in the light, is similar to the wild type strain, except that it lacks luteoxanthin and contains a small amount of cryptoxanthln. In the dark it shows a very marked decrease in total carotenoids. Light-grown cultures of 4 mutant strains with impaired photosynthetic ability (ac-16, ac-21, ac-115, and ac-141) all have characteristic carotenold patterns which distinguish them from the light-grown wild type strain. They share the properties of having higher xanthophyll carotene ratios, lower total carotenoids, and loser [beta]-carotene/[alpha]-carotene ratios than the corresponding wild type culture. The latter 2 properties are also characteristic of the wild type strain cultured in the dark.