Effects of sodium chloride on the fatty acids composition in Boekelovia hooglandii (Ochromonadales, Chrysophyceae)

Abstract

SUMMARY Composition of fatty acids in Boekelovia hooglandii Nicolai et Baas Becking (Chrysophyceae) was investigated as a function of salinity. It was confirmed by gas chromatography that the composition of fatty acids in cells cultured in a 50 mmol L−1 NaCl medium consisted of C14:0, C15:0, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:4, C20:5, C22:5 and C22:6, in which C14:0, C16:0, C16:1, C18:4, C20:0, C20:5, C22:5 and C22:6 were main constituents. When the cells were cultured in a medium with different concentrations of NaCl ranging from 50 to 800 mmol L−1, the mole percentage of fatty acids such as C14:0, C16:0 and C16:1 decreased with increases in the salinity, while the mole percentage of highly polyunsaturated fatty acids such as C18:4, C20:5, C22:5 and C22:6 increased. When the cells were transferred from a 200 mmol L−1 NaCl medium to a 600 mmol L−1 NaCl medium, a decrease in mole percentage of C14:0, C16:0 and C16:1, and an increase in C18:4, C20:5, C22:5 and C22:6 were observed within 4 h. However, no change in the compositions of fatty acids was observed within 4 h when the cells were transferred from a 600 mmol L−1 NaCl medium to a 200 mmol L−1 NaCl one. The increase in the content of highly polyunsaturated fatty acids was considered to reflect the rapid response to upshock and to be the characteristic of salt tolerance in B. hooglandii.