PHOTOSYNTHESIS, LIPIDS AND PROTEINS IN THE CYANOBACTERIUM SYNECHOCYSTIS PCC-6803 AS AFFECTED BY TEMPERATURE

The cyanobacterium Synechocystis PCC 6803 was grown photoautotrophical ly in an inorganic medium at constant growth temperatures of 20, 38 (c ontrol) or 43-degrees-C for 9 h. The up and down-shift of cultivation temperature decreased the growth as measured by culture absorbance and chlorophyll a content. However, high temperature slightly increased t he oxygen evolution while temperature lower than control inhibited oxy gen evolution during the whole incubation period. The protein synthesi s studied by C-14-labeled protein declined under low temperature by ab out 50%. The fatty acid pattern is characterized as lacking in C20/C22 acids but containing large amounts of C-16 and C18 polyunsaturated fa tty acids, 16:2 and 18:3 in particular. The lower temperature increase d the percentage of monounsaturated fatty acids while higher temperatu re increased the saturated fatty acid content in total lipids and lipi d classes studied.