The tolerance of cyanobacterium Cylindrospermopsis raciborskii to low-temperature photo-inhibition affected by the induction of polyunsaturated fattyacid synthesis

Acyl-lipid desaturation introduces double bonds (unsaturated bonds) at spec ifically defined positions of fatty acids that are esterified to the glycer ol backbone of membrane glycerolipids. Desaturation patterns of the glycero lipids of Cylindrospermopsis raciborskii, a filamentous cyanobacterium, wer e determined in cells grown at 35 degreesC and 25 degreesC. The lowering of the growth temperature from 35 degreesC to 25 degreesC resulted in a consi derable accumulation of polyunsaturated octadecanoic fatty acids in all lip id classes. The tolerance to low-temperature photo-inhibition of the C, rac iborskii cells grown at 25 degreesC and 35 degreesC was also compared. The lower growth temperature increased the tolerance of C. raciborskii cells. T hese results strengthen the importance of polyunsaturated glycerolipids in the tolerance to environmental stresses and may give a physiological explan ation for the determinative role of C. raciborskii in algal blooming in Lak e Balaton (Hungary).