Ref ID : 3743
Robert L. Conner and Barbara Y. Stewart; The Effect of Temperature on the Fatty Acid Composition of Tetrahymena pyriformis WH-14. J.Protozool. 23(1):193-196, 1976
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A reduction in the growth temperature of Tetrahymena pyriformis strain WH-14 from 35 degrees C to 15 degrees C resulted in distinct alterations in the fatty acid composition of the glycerophospholipids. The proportion of normal saturated acids declined from 26 to 19%; palmitoleic acid increased by 6%, and the composition of the polyunsaturated fatty acids increased in 18:2 delta(6,11)(n) and decreased in 18:2 delta(9,12)(n) and 18:3 delta(6,9,12)(n). The unsaturation index (the average number of double bonds/100 molecules) did not change with a shift in temperature. Two biosynthetic pathways exist in Tetrahymena for the formation of unsaturated fatty acids. The observed changes in fatty acid composition that accompany a lowering of the environmental temperature can be accounted for by a reduction in the accumulation of products of the fatty acid pathway leading to the formation of gamma-linolenic acid [16:0(n) - 18:0(n) - 18:1 delta(9)(n) - 18:2 delta(9,12)(n) - 18:3 delta(6,9,12)(n)] and an increase in the components of the pathway leading to the formation of 18:2 delta(6,11)(n) [16:0(n) - 16:1 delta(9)(n) - 18:1 delta(11)(n) - 18:2 delta(6,11)(n)]. The data suggest that the regulatory mechanism in Tetrahymena differs from that found in some bacteria where a simple substitution of unsaturated fatty acids for saturated fatty acids occurs at low culture temperatures.