Composition of polar lipid acyl chains of Bacillus stearothermophilus as affected by temperature and calcium.
Bacillus stearothermophilus was grown within the temperature range of 48 to 68 degrees C in a complex medium and in the range of 45 to 72 degrees C in the presence of 2.5 mM Ca2+. The main fatty acids of lipid extracts contain 15 to 17 carbon atoms, mostly branched-chain species. The most prevalent saturated straight-chain fatty acid is n-C16. The total amount of branched-chain species decreases with increasing temperature of growth from 48 to 68 degrees C, whereas the straight-chain species increase. Thus, n-C16 almost doubles while i-C16, i-C17 and a-C17 decrease by 41.2, 28.9 and 41.9%, respectively. In the presence of Ca2+, the lipid metabolism favours the biosynthesis of straight-chain fatty acids with depression of branched-chain species, especially at lower temperatures. At high temperatures, Ca2+ has a less pronounced effect in the lipid biosynthesis. However, above 68 degrees C, a significant decrease is observed among the branched-chain fatty acids i-C15, i-C17 and a-C17 with a consequent increase in n-C16. Furthermore, a remarkable increase is observed in oleic acid (from 2.7% at 68 degrees C to 11.5% at the extreme 72 degrees C.
Martins
L O
LO
Centro de Biologia Celular, Universidade de Coimbra, Portugal.
Jurado
A S
AS
Madeira
V M
VM
D000215:Acylation; D002118:Calcium / Q000494:pharmacology*; D005227:Fatty Acids / Q000302:isolation & purification / Q000378:metabolism*; D001411:Geobacillus stearothermophilus / Q000187:drug effects / Q000254:growth & development*; D013696:Temperature
D005227:Fatty Acids; D002118:Calcium