title: Effects of the temperature range and the lack of beta-ketoacyl acyl-carrier protein synthase II on fatty acid synthesis in Escherichia coli K12 after shifts in temperature.
abstract: Escherichia coli K12 cells grown at higher temperatures and then subjected to lower temperatures produce fatty acids with higher unsaturated/saturated ratios than cells completely adapted to the lower temperatures (Okuyama et al. (1982) J. Biol. Chem. 257, 4812-4817). This hyper-response was not an artefact of chloramphenicol treatment and was observed when the shift-down was more than 20 degrees C in the cells grown at either 40 degrees C or 35 degrees C. In contrast, cells grown at either 25 degrees C or 30 degrees C showed no appreciable hyper-response in terms of unsaturated/saturated ratio on temperature shifts to as low as 10 degrees C. By combining shift-down and shift-up experiments, we could show the presence of different types of temperature dependency in the fatty acid-synthesizing systems of cells grown at various temperatures. Contrary to wild-type cells which synthesized mainly cis-vaccenate on down-shift to 10 degrees C, a mutant strain lacking beta-ketoacyl acyl-carrier protein synthase II synthesized more palmitoleate (16:1) and less palmitate at 10 degrees C than at 40 degrees C. The average chain lengths of saturated and unsaturated fatty acids also changed, but differently, between the mutant and wild-type cells on shifts of temperature. Thus, the mutant strain has a temperature-dependent fatty acid-synthesizing system qualitatively different from that seen in a wild-type strain.
mesh_terms: D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000378:metabolism*; D000085:Acetates / Q000378:metabolism; D019342:Acetic Acid; D000217:Acyltransferases / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D005227:Fatty Acids / Q000096:biosynthesis*; D007700:Kinetics; D013696:Temperature
chemical_list: D000085:Acetates; D005227:Fatty Acids; D002701:Chloramphenicol; D000217:Acyltransferases; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D019342:Acetic Acid