Abstract:
The fatty acid composition of the total cellular lipids of Choanephora
cucurbitarum incubated for 96 hrs on either glucose-ammonium sulfate or
malt-weast extract media was determined. The major fatty acids were palmitic,
palmitoleic, stearic and linoleic acids. The saturated fatty acid possessing
the longest acyl chain was stearate (C 18:0). The presence of glutamic
acid (2.0 x 10-1% or 1.36 x la-2M) in either of the above growth media
resulted in increase in percent of 1f-linolenic acid, decrease in percent
of linoleic ~iCid and appearance of a new series of fatty acid> C ~8 e.g. C ",,,,'V'
C2k:O, C26,O. The addition of glutamic acid had no effect on the lipid yield
but slightly decreased the degree of unsaturation.
Compounds which duplicated the effect of glutamic acid were acetate,
malate, citrate, succinate, 0( -ketoglutarate, prOline, -y -aminobutyric
acid and glucose (3%) but not aspartic acid or alanine.
~o correlation was found between glutamic acid pool concentration and
the presence in the growth medium of those compounds which stimulate long
chain fatty acid production.
Four hours of incubation with 27 JJ 1-1 glutamate supported the production
of long chain fatty acids. This stimulation is inhibited if 272 .u M
isophthalic acid is added with 27 AJ M glutamate. But, long chain fatty
acids were detected when 27 JJ M eX -ketoglutarate is also present in the
incubation mixture.
Five hours of incubation with 100 ,Mg/ml of cycloheximide resulted
in over 9CY/o inhibition of cytoplasmic :protein synthesise Glutamate
(27 .uM) enhanced the synthesis of long chain fatty acids under these
conditions.
These findings are discussed in an attempt to provide a plausible
explanation COmmon to compounds that support the production of long chain
fatty acids.
