title: Lipopolysaccharide changes and cytoplasmic polyphosphate granule accumulation in Pseudomonas aeruginosa during growth on hexadecane.
abstract: Pseudomonas aeruginosa ATCC 9027 grew on 0.5% (v/v) hexadecane as a sole carbon source in a chemically defined medium which required the addition of Fe3+ and Ca2+. There was a variable and extended lag period before an active growth rate was attained. Visible light microscopic evidence revealed that the bacteria did not adhere to hexadecane droplets suggesting the absence of a bioemulsifier. When compared with glucose-grown cells, hexadecane-grown cells produced 75% less lipopolysaccharide (on a total protein basis); this lipopolysaccharide contained 30-40% less carbohydrate, yet 50-75% more 2-keto-3-deoxyoctonate. These chemical changes made the cell surface appear more hydrophobic when tested in a biphasic hydrophobicity index system. Electron microscopy of thin sections and freeze etchings revealed hexadecane-grown cells contained granules which were judged to be polyphosphate by energy dispersive X-ray analysis. There was no apparent major morphological envelope alteration within the two cell types.
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D002462:Cell Membrane / Q000648:ultrastructure; D003470:Culture Media; D003594:Cytoplasmic Granules / Q000648:ultrastructure*; D005613:Freeze Etching; D005947:Glucose / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism*; D008854:Microscopy, Electron; D011122:Polyphosphates; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000473:Alkanes; D003470:Culture Media; D008070:Lipopolysaccharides; D011122:Polyphosphates; C007932:n-hexadecane; D005947:Glucose