The fatty acid composition and temperature/growth characteristics of a psychrophilic bacterium, strain ACAM 456, isolated from Antarctic sea-ice is reported. The bacterium produced acyl components that may be grouped in three different carbon chain types: even-chain, odd-chain and iso-branched odd-chain. The proportions of these chain types varied according to growth temperature, and were manipulated by growth on L-serine, L-leucine or propionic acid as sole carbon sources, De novo fatty acid synthesis was investigated using sodium [1-14C]acetate, L-[U-14C]leucine and L-[U-14C]serine as radioactive precursors. Compared with a control culture, resuspension of mid-exponential phase cells in artificial seawater led to a change in the selection and/or intracellular availability of acyl chain primer molecules. The proportion of radiolabel incorporated into even-chain length components from cells declined, whereas the percentage of radiolabel present in odd-chain length components increased. An increase in incubation temperature augmented this effect, and also elicited a rise in the proportion of label present in branched-chain products. ACAM 456 manipulated the utilization of acyl chain primer molecules as an adaptive response to changes in environmental conditions. In particular, the regulation of odd-chain length fatty acids is described as a novel adaptational response.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Microbiology
Research Field:	Bacteriology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
UTAS Author:	Nichols, DS (Dr David Nichols)
ID Code:	6730
Year Published:	1996
Web of Science® Times Cited:	25
Deposited By:	Agricultural Science
Deposited On:	1996-08-01
Last Modified:	2011-08-16
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