Changes of C-Phycocyanin in Synechococcus 6301 in Relation to Growth on various Sulfur Compounds

Synechococcus, C-Phycocyanin, Sulfur Nutrition The cyanobacterium Synechococcus 6301 is able to use a lim ited number o f sulfur compounds as the only source o f sulfur supply such as sulfate, thiosulfate, thioacetic acid, mercaptoacetic acid, thioacetamide, L-cysteine and glutathione. Compounds containg thioether linkages such as methionin or S-methylcysteine and all compounds investigated so far containing sulfonic acid structures do not support growth. Growth inhibiton was observed by addition o f aminomethanesulfonic acid or cysteamine. When non-growth sustaining sulfur compounds are added as sulfur source, the C-phycocyanin content o f the Synechococcus cultures decreased drastically, causing a shift in color from bluegreen to yellow-green. An analysis reveals the degradation o f C-phycocyanin whereas chlorophyll formation still proceeds to a certain degree in growing sulfur-starved cells. Supplem entation o f a suitable sulfur source induces a period o f intense and preferential C-phycocyanin synthesis prior to resumption o f normal growth.