Increase of ornithine amino lipid content in a sulfonolipid-deficient mutant of Cytophaga johnsonae.
The gram-negative gliding bacterium Cytophaga johnsonae contains not only large quantities of unusual sulfonolipids but also, as we report here, a second class of unusual lipids. These lipids were detected and quantified by two-dimensional thin-layer chromatography of lipids from cells grown in the presence of [14C]acetate and shown by chemical studies to be alpha-N-(3-fatty acyloxy fatty acyl)ornithines. Like the sulfonolipids, these ornithine lipids were localized in the outer membrane (whereas phosphatidylethanolamine was the predominant lipid of the inner membrane). In a sulfonolipid-deficient mutant, the missing lipid was replaced, specifically, by an increased amount of ornithine lipid. Cells grown in liquid media contained predominantly ornithine lipids with nonhydroxylated residues in the O-fatty acyl position. In contrast, surface-grown cells contained a high proportion of ornithine lipids in which the O-fatty acyl group was 3-hydroxylated. The sulfonolipids and ornithine lipids are apparently coregulated in the sense that, regardless of perturbations caused by mutation or growth conditions, their total amounts remain constant at 40% of total cell lipid.
Pitta
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Department of Molecular and Cell Biology, University of Connecticut, Storrs 06269-2131.
Leadbetter
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Godchaux
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D002462:Cell Membrane / Q000378:metabolism; D003589:Cytophaga / Q000235:genetics* / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000235:genetics* / Q000302:isolation & purification; D009154:Mutation; D009952:Ornithine / Q000378:metabolism* / Q000031:analogs & derivatives
D008055:Lipids; C051524:ornithine containing aminolipid; C015518:sulfolipids; D009952:Ornithine