Lipid and fatty acid composition of Gluconobacter oxydans before and after intracytoplasmic membrane formation

Abstract

Gluconobacter oxydans differentiates by forming quantities ofintracytoplasmic membranes at the end of exponential growth, and this formation occurs concurrently with a 60% increase in cellular lipid. The present study was initiated to determine whether this newly synthesized lipid differed from that extracted before intracytoplasmic membrane synthesis. Undifferentiated exponential-phase cells were found to contain 30% phosphatidylcholine, 27.1% cardiolipin, 25% phosphatidylethanolamine, 12.5% phosphatidylglycerol, 0.4% phosphatidic acid, 0.2% phosphatidylserine, and four additional unidentified lipids totaling less than 5%. The only change detected after formation of intracytoplasmic membranes was a slight decrease in phosphatidylethanolamine and a corresponding increase in phosphatidylcholine. An examination of lipid hydrolysates revealed 11 different fatty acids in the lipids from each cell type. Hexadecanoic acid and monounsaturated octadecenoic accounted for more than 75% of the total fatty acids for both cell types. Proportional changes were noted in all fatty acids except octadecenoate. Anteiso-pentadecanoate comprised less than 1% of the fatty acids from undifferentiated cells but more than 13% of the total fatty acids from cells containing intracytoplasmic membranes. These results suggest that anteiso-pentadecanoate formation closely parallels the formation of intracytoplasmic membranes. Increased concentrations of this fatty acid may contribute to the fluidity necessary for plasma membrane convolution during intracytoplasmic membrane development. viously described (6). Large numbers of cells were grown in a fermentor and prepared for lipid extraction as described by Heefner and Claus (16). The growth characteristics in the fermentor and the changing microscopic appearance of these cells during growth are fully described elsewhere (16). Labeling lipids with 32P and "4C. For labeling lipids with 32P, 200 ml of Heefner and Claus's medium (16) was heat sterilized in 2,000-ml nephelometer flasks (Beilco Glass, Inc.). Filter-sterilized [32P]phosphoric acid was added to a concentration of 6.25 #Ci/ml. Each flask was incubated at 28°C with reciprocal shaking at 200 strokes/min at 3.8-cm stroke amplitude. Early exponential-phase (early EXP) cultures were harvested at 0.3 optical density unit at 620 nm (Bausch and Lomb Spectronic 20 spectrophotom-38

Phospholipid composition of gliding bacteria: oral isolates of Capnocytophaga compared with Sporocytophaga

“…The cellular lipids in the gliding bacteria examined in this study were similar to that observed by other investigators for several gramnegative bacteria (4,15,20,23,24). The acetonesoluble or neutral glycolipid fraction accounted for 33 to 54% of the weight of the total cellular lipids of Capnocytophaga ( Table 1).…”

“…This lipid, as ( Table 2). which was iodine and ninhydrin positive and LPE) ac-molybdate negative, was identical in its chro-13% of the e remainder Ls (approxied between itified phose latter two e characterined in this ary with the ear whether products or owever, the I crop or for 26,1979 on September 8, 2020 by guest http://iai.asm.org/ Downloaded from matographic characteristics to an ornithine lipid described by Makula and Finnerty (34) in Desulfovibrio gigas and similar in its chromatographic properties to that reported in other procaryotes (15,29,46,52,53,(58)(59)(60)).…”

Effect of Intracytoplasmic Membrane Development on Oxidation of Sorbitol and Other Polyols by Gluconobacter oxydans

“…We found that this increase in oxidative activity was paralleled by the formation of intracytoplasmic membranes (3,7) and an increase in cellular phospholipids (18). Evidenced from thin sections (7) and qualitative fatty-acid analyses (19) strongly suggested that these intracytoplasmic membranes resulted from continued synthesis and subsequent convolution of the plasma membrane after cell division stopped.…”

“…Thus, it appears that membrane-bound dehydrogenases play a predominant role in sorbitol oxidation by whole cells, and it is conceivable that much if not all of the oxidation product may be formed and released without having to be transported inside the cell. Our previous studies with G. oxydans demonstrated that intracytoplasmic membranes were extensions of the plasma membrane (7) and that cells containing intracytoplasmic membranes and those lacking these extra membranes contained the same types of fatty acids (19). Therefore, we previously assumed that intracytoplasmic membranes were similar if not identical to the plasma membrane of the cell.…”

“…However, we were aware that alternate explanations were also possible. For example, all of our previous studies (3,7,18,19) used glycerol-grown cells, and it was conceivable that continued phospholipid and plasma membrane synthesis occurred only when cells were grown in media containing glycerol. It was also possible that increased respiration rates were due to increased quantities of soluble polyol dehydrogenases or caused by changes in allosteric controls as cells shifted from exponential growth to the stationary phase.…”