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An analysis of the lipids of the fat body of Locusta migratoria showed that approximately 97% are triglycerides and 2-3% diglycerides; free fatty acids and phospholipids were present only in small amounts. In the hemolymph, diglycerides and phospholipids were the major lipid components; free fatty acids were present in very small amounts, triglycerides were absent. The concentration of the diglycerides in the hemolymph was found to increase with the age of the locust and during sustained flight; the phospholipids remained constant. The concentration of the free fatty acids in the tissue and hemolymph was also increased during flight. When fat body tissue was incubated in vitro with [1-14C]palmitate, the acid was incorporated into the di- and triglycerides of the tissue. The specific activity of the diglycerides was at least 50 times higher than that of the triglycerides. When prelabeled tissue was transfered into a medium containing hemolymph, diglycerides were released into the medium. The amount of diglyceride released was dependent on the time of incubation and on the amount of hemolymph which was added to the medium. Although the amount of diglycerides which was released, was greater than their concentration in the tissue, the amount of the latter did not change. However, their specific activity was very markedly reduced. When the fat body tissue was prelabeled in vivo and the specific activity of the di- and triglycerides was identical, the specific activity of the diglycerides was not reduced during diglyceride release. When fat body tissue of locusts after flight was incubated with [1-14C]palmitate, incorporation of the acid into the diglycerides was very markedly reduced. This inhibition was reversed by the addition of glucose to the medium. When prelabeled tissue of locusts after flight was incubated in hemolymph obtained from the same locusts, diglycerides and free fatty acids were released into the medium. [ABSTRACT FROM AUTHOR]

The lipids of Corynebacterium ovis (strain B1/50) were successively extracted by petroleumether, ethanol-ether (1:1, v/v) and chloroform. The bulk of the petroleum-ether extract consists mainly of sodium corynomycolate together with sodium salts of C14, C16 and C18 fatty acids. Some triglycerides and free fatty acids were also detected. Isolated from the ethanol-ether extract were: hydrocarbons, palmitone, free corynomycolic acid, a small amount of free corynomycolenic acid and a peptidolipid fraction. The phospholipid fraction contains a mixture of closely related compounds, having about 3.5% P. By hydrolysis, they are split into lipid components (50-70 % of the initial products; mixtures of C16 and C18 fatty acids and corynomycolic acid), and water soluble components (glycerol, glycerophosphoric acid, inositol, arabinose, and small amounts of amino acids). Complex substances, soluble in ether, having a high content, of phosphorus (3.2 to 4.5%) were isolated from the chloroform extract. All of them contain glycerol, along with ethanolamine and sugars (glucose, galactose, arabinose, and a fast moving unidentified sugar) in one case, and with amino acids (chemically bound) in two other cases. Moreover, one third of the chloroform extract, is made of a fraction (10.8% N and 1.3% P) insoluble in ether, which gives, by hydrolysis, 19% of lipid components and a polypeptide containing all the usual amino acids; the structure of this last fraction is discussed. [ABSTRACT FROM AUTHOR]

The walls of Nocardia kirovani are composed of three main constituents: the peptidoglycan matrix, a polysaccharide polymer and a variety of free and bound lipids. The free lipids represent 17.5% (dry weight) of the walls and consist for the major part of C16-18 fatty acids and nocardic acids, and for the minor part, of nocardones, triglycerides and carotenoid pigments. The nocardic acids were identified as tri- and tetra-unsaturated, α-branched, β-hydroxylated compounds C58H110O3--C66H124O3, the nocardones as tri- and tetra-unsaturated ketones C57H106O--C63H118O, and the main carotenoid pigment as phlei-xantophylle palmitate. Esters of glycerol with C14C16C18 fatty acids and, for some of them, with odd numbered poly-unsaturated acids containing 35 to 45 carbon atoms, were also identified, Bound lipids represent about 20% (dry weight) of the walls and consist mainly of nocardic acids probably ester-linked to an arabinogalactan polymer. The peptidoglycan (about 40% dry weight) is composed of β-1,4-N-acetylglucosaminyl-N-glycolylmuramic acid disaccharide units that are substituted by diamidated L-Ala-D-αGln-(L)- A2pm-(D)-NH2 tripeptides and diamidated L-Ala-D-αGln-(L)-A2pm-(D)-NH2(L)-D_Ala tetrapeptides, where A2pm is meso-diaminopimelic acid.Crosslinking between some of the peptide units is mediated through D-Ala-(D)-A2pm linkages (peptidoglycan of ehemotype I). [ABSTRACT FROM AUTHOR]

Composition of lipids of the forehead, nose surface, and contents of sebaceous follicles of the nose is reported for subjects whose flora is predominantly C. acnes I or C. acnes II. No differences in any of the parameters examined could be attributed to the group of C. acnes which the subjects carried. The extent of triglyceride (TG) hydrolysis was a function of the lipid extraction site with nose follicles > nose surface > forehead surface, but there was extensive subject-to-subject variation at each site. The fatty acid composition data showed that the free fatty acid (FFA) pools were higher in saturated acids and lower in unsaturated acids than were the remaining TG pools. This difference in fatty acid composition cannot be attributed to specificity of hydrolysis by C. acnes. The results are discussed in terms of the hypothesis that hydrolysis of sebum TG by microbial lipase(s) gives rise to FFA, which cause follicular irritation leading to acne. [ABSTRACT FROM AUTHOR]

The importance of lipid dependent yeasts in the hydrolysis of triglycerides in human skin was investigated by selective antibiotic therapy and monitoring of the lipid composition and the microbial flora in healthy volunteers. The yeast density was reduced with topical amphotericin treatment. In the presence of high populations of Corynebacterium acnes, lipid composition was unchanged. When C. acnes was also inhibited by systemic demethylchlortetracycline, triglyceride hydrolysis was reduced to very low levels. The aerobic cocci were not implicated in lipid hydrolysis. [ABSTRACT FROM AUTHOR]

The response of the sebaceous gland to total caloric deprivation was studied in 18 obese patients undergoing fasts for periods of four to eight weeks. Sebum production was measured in 11 of the patients and was found to decrease in each individual, with an average reduction of 40%. Diminished secretion usually occurred by the fourth week but was sometimes seen as early as one or two weeks. The composition of the sebum, analyzed in 14 patients, was also altered, and this could be detected as early as five days after the onset of fast. The qualitative changes in surface lipid consisted of a reduction in the amount of triglyceride fatty acids, wax esters, cholesterol and cholesterol esters but with no significant alteration in the amount of squalene. [ABSTRACT FROM AUTHOR]

The aerobic microflora of the scalp, predominantly cocci, was virtually eliminated by the daily application of 1% aqueous neomycin for one month. This was done to test whether these organisms are an important source of the lipases which liberate fatty acids from the sebaceous triglycerides. This treatment had no effect on the proportion of free fatty acids in the surface lipids as determined by thin layer chromatography. The follicle-residing anaerobic C. acnes, was not attacked by neomycin and the yeast-like fungus P. ovale increased somewhat. The percentage of free fatty acids in any individual's sebum before and after treatment was positively correlated with the density of C. acnes. The latter organism is probably mainly responsible for lipolysis of triglycerides. [ABSTRACT FROM AUTHOR]

Serum lipids of overnight fasting and of three-hour postprandial blood were compared for 635 Anglo- and 459 Spanish-American men, ages 20 through 79 years. More than one-third of the test population were institutionalized in a state hospital for mental or geriatric patients. In the male Spanish-American population in an environment typical for the ethnic group, serum fatty acids, triglycerides and cholesterol peak early in life, ten to thirty years before the corresponding peaks in Anglo-American men. Peak concentrations are not significantly different in normal Spanish- and Anglo-Americans, but concentrations are greater in Anglos during the fifties and sixties when their incidence of cardiovascular disease is highest. Postprandial means for fatty acids and triglycerides in normal men tend to parallel fasting curves at levels 20 to 40% higher for fatty acids and 60 to 100% higher for triglycerides. In institutionalized mental and geriatric patients, maximum serum lipid values in Spanish- and Anglo-American men occur in the same or contiguous decades, not showing the normal contrasts with age or ethnic division. Except for phospholipids, all lipid concentrations are lower in institutionalized than normal men for all decades other than in the twenties. The low serum lipid concentrations in Spanish men during the later decades of life, as well as the low incidence of cardiovascular deaths in Spanish males, appear to relate the lower cardiovascular death rate in New Mexico in part to the ethnic profile. [ABSTRACT FROM AUTHOR]