The formation of heteroagglutinins in rats "chemically" splenectomized by ethyl palmitate, in comparison to animals surgically splenectomized.

In Wistar rats "chemically splenectomized" by an i.v. injection of ethyl palmitate the formation of heteroagglutinins against human O-erythrocytes has been followed. Ethyl palmitate applied 2 hrs before immunization induced on the 5th day a significant decrease of the antibody level. This temporary inhibition, however, was at a later stage replaced by a significant increase of antibody level with the peak of 8--14 days. Animals surgically splenectomized 24 hrs prior to immunization displayed a weak antibody response throughout the experiment. An injection of the ethyl palmitate on the 6th day after immunization induced a pronounced and persistent decrease of the antibody level. Surgical splenectomy performed within the same interval had a comparable effect. The experiments revealed that the inhibitory effect of ethyl palmitate on antibody production was temporary only, and at a later stage could be compensated by an enhanced antibody activity.     

The inhibitory effect of methyl palmitate on heteroagglutinin formation in rats.

In Wistar rats the immunosuppressive effect of methyl palmitate on the formation of heteroagglutinins against human O-group erythrocytes was followed. An i.v. injection of methyl palmitate both delayed the heteroagglutinin formation and decreased its intensity. The inhibitory effect of methyl palmitate was not accompained by the subsequent hyperactive phase as could be observed in the previous experiments using ethyl palmitate.     

Triglyceride Interesterification by Lipases: 2. Reaction parameters for the reduction of trisaturated impurities and diglycerides in batch reactions

A model system consisting of pure triolein and palmitic acid and LipozymeTM, an immobilized lipase (E.C. 3.1.1.3.). has been used to determine the effects of various reaction parameters on the reaction rate and the formation of by-products in the interesterification reaction. The goal was to minimize the level of diglycerides and eliminate trisaturated triglycerides at an endpoint chosen so that the results could be applied to the production of cocoa butter substitutes. The levels of diglycerides, which are essential reaction intermediates, and trisaturated glycerides, which are believed to be formed as a result of spontaneous acyl migration of mono- and diglyceride intermediates, were determined at a defined endpoint. A lag period was observed in which no tripalmitate was formed. The content of Lipozyme used was the most powerful factor in eliminating tripalmitate formation and reducing diglycerides; by using large quantities of Lipozyme, the reaction reached the endpoint before the tripalmitate formation became measurable and low levels of diglycerides were formed. The effects of varying the ratio of palmitic acid to triolein were investigated. A complex relationship between the ratio of substrate components emerged in which the diglyceride content increased with increasing triolein concentration and the tripalmitate content was lowest at a molar ratio of palmitic acid to triolein of 3.5. The reaction was run at 70, 80, and 90°C; best results were obtained at 70°. The water activity of the reaction was adjusted prior to catalysis and maintained during the reaction by equilibrating the reaction mixture and enzyme and running the reaction in an atmosphere of controlled water activity. A direct relationship between diglycerides and water activity was observed, and the level of tripalmitate formed corresponded to the time required to reach the endpoint. The reaction system was tested using ethyl palmitate instead of palmitic acid as acyl donor; the diglyceride content again increased with increasing water activity, but larger amounts of diglycerides were formed. Much shorter reaction times were required, with small quantities of tripalmitate formed.     

Substrate specificity of regiospecific desaturation of aliphatic compounds by a mutant Rhodococcus strain

Substrate specificity of cis-desaturation of alipahtic compounds by resting cells of a mutant, Rhodococcus sp. strain KSM-MT66, was examined. Among substrates tested, the rhodococcal cells were able to convert n-alkanes (C13-C19), 1-chloroalkanes (C16 and C18), ethyl fatty acids (C14-C17) and alkyl (C1-C4) esters of palmitic acid to their corresponding unsaturated products of cis configuration. The products from n-alkanes and 1-chloroalkanes had a double bond mainly at the 9th carbon from their terminal methyl groups, and the products from acyl fatty acids had a double bond mainly at the 6th carbon from their carbonyl carbons.     

Acylation of the lymphoma transmembrane glycoprotein, GP85, may be required for GP85-ankyrin interaction.

The lymphoma plasma membrane glycoprotein, GP85, is a transmembrane glycoprotein that binds directly to ankyrin, a molecule known to link the plasma membrane with the underlying cytoskeleton. In this study, we have demonstrated that palmitic acid is incorporated into GP85 in vivo and that the amount of palmitic acid incorporated is greatly stimulated during lymphoma cap formation. The majority of the incorporated palmitic acid appears to be strongly linked to GP85 since it is not dissociated by strong detergents (e.g. sodium dodecyl sulfate) or by chloroform/methanol extraction, but is labile to alkaline or acid hydrolysis. Furthermore, we have established that deacylation of GP85 (i.e. removal of the palmitic acid moiety from GP85 by 1 M hydroxylamine treatment) significantly reduces the binding affinity between GP85 and ankyrin, and reacylation of GP85 restores the binding affinity. These findings suggest that fatty acid acylation of GP85 by palmitic acid may be required for the stable attachment of the cytoskeleton to the lymphoma plasma membrane.     

Induction of Antibiotic Formation in Streptomyces sp. No. 362 by the Change of Cellular Fatty Acid Spectrum

Microorganisms which require oleic acid for the formation of antibiotics were screened. Streptomyces sp. No. 362, one of the selected organisms, produced antimicrobial substances only when oleic acid, palmitic acid or the high concentration of l-glutamic acid (or l-glutamine) was supplemented to the medium. The cellular fatty acid composition was changed by the supplement of these fatty acids, but not by l-glutamic acid (or l-glutamine). Antibiotic-producing cells had about 4 to 10 times larger amino acid pools, especially l-glutamic acid pool, and hexosamine pools. The ability for l-glutamate uptake of cells grown in the oleic or palmitic acid supplemented medium was markedly enhanced and the efflux of the accumulated l-glutamate was reduced. The antibiotic produced by this strain was identified as one of the streptothricin-group antibiotics and the role of these additives in the antibiotic formation is discussed.     

Substrate Specificity of Regiospecific Desaturation of Aliphatic Compounds by a Mutant Rhodococcus Strain

Substrate specificity of cis-desaturation of alipahtic compounds by resting cells of a mutant, Rhodococcus sp. strain KSM-MT66, was examined. Among substrates tested, the rhodococcal cells were able to convert n-alkanes (C13-C19), 1-chloroalkanes (C16 and C18), ethyl fatty acids (C14-C17) and alkyl (C1-C4) esters of palmitic acid to their corresponding unsaturated products of cis configuration. The products from n-alkanes and 1-chloroalkanes had a double bond mainly at the 9th carbon from their terminal methyl groups, and the products from acyl fatty acids had a double bond mainly at the 6th carbon from their carbonyl carbons.     

Fatty acid biosynthesis in the integument tissue of Triatoma infestans

1. The biosynthesis of lipids and their distribution in several tissues were investigated by injection of 1-14C acetate in females and 5th instar nymphs of the hematophagous hemiptera T. infestans. 2. Biosynthesis of palmitic, palmitoleic, stearic, oleic and very long chain fatty acids up to 26 carbons and hydrocarbons, was shown. They were found in haemolymph, fat body, integument, epicuticle and oocytes with special distribution. 3. Epicuticular hydrocarbon labelling was shown to precede that of haemolymph hydrocarbons. 4. Radioactivity incorporation into each lipid class depends on the developmental stage and the time after injection. 5. "In vitro" incubation of integument tissue with 1-14C acetate demonstrated the biosynthesis of palmitic and stearic acids, a low desaturation to oleic and palmitoleic and an elongation to acids of up to 34 carbons. Hydrocarbons were also synthesized. 6. Haemolymph in the incubation medium has a positive effect on the release of newly-synthesized fatty acid and unsaponifiable material from the integument.     

Long-chain fatty acid perturbations in Mycoplasma pneumoniae

The fatty acid content of Mycoplasma pneumoniae increased 2.5- to 9.6-fold when the growth medium was supplemented with a saturated, unsaturated, or beta-hydroxy fatty acid, the greatest increase occurring with palmitic acid. The amount of each supplemented fatty acid found within this organism was 2.8 to 5.5% of the total fatty acid content; the exception was palmitic acid. Up to 57% of the palmitic acid was utilized from the supplemented medium, whereas only 0.2 to 10% of the other fatty acids was utilized. Chromatographic and isotopic analyses revealed that 22% of the labeled palmitic acid incorporated from the palmitic acid-supplemented medium remained free in this organism. Also, even though complex lipid synthesis increased a minimum of 3.8-fold under these conditions, this mycoplasma continued to incorporate intact complex lipids from the growth medium. Bacteriostatic and bactericidal studies which used high concentrations of various long-chain fatty acids showed that only palmitic, myristic, and beta-hydroxydecanoic acids were not bactericidal. The addition of palmitic acid to the growth medium resulted in the formation of exceedingly long, filamentous cells in approximately 25% of the population. Osmotic fragility and electron spin resonance spectroscopy studies showed a correlation among this increased fatty acid content, decreased membrane fluidity, and the increased osmotic fragility of palmitic acid-grown cells. In addition, these cells had a lowered cholesterol content. The effect of such compositional changes on osmotic fragility is discussed in this paper. Finally, the profound increase in the total fatty acid content of palmitic acid-grown cells altered neither sensitivity to tetracycline or erythromycin nor the amount of hydrogen peroxide secreted.     

Structure and phase behavior of hydrated mixtures of L-dipalmitoylphosphatidylcholine and palmitic acid. Correlations between structural rearrangements, specific volume changes and endothermic events

Several new features of the phase diagram of L-dipalmitoylphosphatidylcholine (DPPC)/palmitic acid mixtures in excess water were established by means of static and time-resolved X-ray diffraction, densitometry and differential scanning calorimetry (DSC). At low temperatures, palmitic acid has a biphasic effect on the lamellar subgel phases: at concentrations below 5-6 mol%, it prevents formation of the DPPC subgel phase (Lc), while at higher contents (between about 40 and 90 mol%) another subgel phase (Lccom) is formed as a result of lipid co-crystallization at 1 DPPC: 2 palmitic acid stoichiometry. A crystalline palmitic acid phase separates from Lccom above 70-80 mol% of fatty acid. The Lccomphase transforms into a lamellar gel phase (L beta) in an endothermic transition centered at 38 degrees C. At high temperatures, the mixtures form hexagonal liquid-crystalline phase (HII) in the region of 60-70 mol% and an isotropic phase (I) at 90-100 mol% of palmitic acid. No coexistence of HII phase with the fluid lamellar phase of DPPC was observed at intermediate compositions (20 and 50 mol% of palmitic acid) but rather formation of a complex phase with non-periodic geometry characterized by molten chains and a broad, continuous small-angle scattering band. No evidence for fluid phase coexistence was found also at compositions between HII and I phases. The L beta--HII transition at 60-70 mol% of palmitic acids is readily reversible and two-state in both heating and cooling modes. It is characterized by the coexistence of initial and final phases with no detectable intermediates by time-resolved and static X-ray diffraction. The crystalline-isotropic transition in palmitic acid is two-state only in heating direction. On cooling, it is characterized by strong undercooling and gradually relaxing lamellar crystalline structures. The slowly reversible Lccom--L beta transition proceeds continuously through intermediate states. Although clearly discernible by both DSC and X-ray diffraction, it is not accompanied by specific volume changes.     

Anaerobic biodegradation of oleic and palmitic acids: evidence of mass transfer limitations caused by long chain fatty acid accumulation onto the anaerobic sludge

Palmitic acid was the main long chain fatty acids (LCFA) that accumulated onto the anaerobic sludge when oleic acid was fed to an EGSB reactor. The conversion between oleic and palmitic acid was linked to the biological activity. When palmitic acid was fed to an EGSB reactor it represented also the main LCFA that accumulated onto the sludge. The way of palmitic acid accumulation was different in the oleic and in the palmitic acid fed reactors. When oleic acid was fed, the biomass-associated LCFA (83% as palmitic acid) were mainly adsorbed and entrapped in the sludge that became "encapsulated" by an LCFA layer. However, when palmitic acid was fed, the biomass-associated LCFA (the totality as palmitic acid) was mainly precipitated in white spots like precipitates in between the sludge, which remained "non-encapsulated." The two sludges were compared in terms of the specific methanogenic activity (SMA) in the presence of acetate, propionate, butyrate, and H(2)CO(2), before and after the mineralization of similar amounts of biomass-associated LCFA (4.6 and 5.2 g COD-LCFA/g of volatile suspended solids (VSS), for the oleic and palmitic acid fed sludge, respectively). The "non-encapsulated," sludge exhibited a considerable initial methanogenic activity on all the tested substrates, with the single exception of butyrate. However, with the "encapsulated" sludge only methane production from ethanol and H(2)/CO(2) was detected, after a lag phase of about 50 h. After mineralization of the biomass-associated LCFA, both sludges exhibited activities of similar order of magnitude in the presence of the same individual substrates and significantly higher than before. The results evidenced that LCFA accumulation onto the sludge can create a physical barrier and hinder the transfer of substrates and products, inducing a delay on the initial methane production. Whatever the mechanism, metabolic or physical, that is behind this inhibition, it is reversible, being eliminated after the depletion of the biomass-associated LCFA.     

Whole cell catalyzed esterification of fatty acids to biodiesel using Aspergillus sp.

Abstract

Powdered biomass of Aspergillus sp. (RBD01) was used to carry out esterification of long chain fatty acids for biodiesel production. Dry biomass of Aspergillus sp. at 20% (w/w) with respect to the fatty acid was able to completely esterify oleic acid to ethyl ester at 35°C, in 36 h, with step wise addition of alcohol. Similar conditions also resulted in yield of 64.5% and 58% of ethyl ester from stearic acid and palmitic acid, respectively. However, the presence of methanol resulted in 87.5%, 71% and 41% of methyl ester from oleic, palmitic and stearic acid. Furthermore, it was found that the efficiency of biomass decreased by only 10% with its repeated use up to four cycles.     

Positional Distribution of Fatty Acids in Glycerolipids of the Marine Red Alga, Porphyra yezoensis

The positional distribution of fatty acids in glycerolipidsfrom thalli of Porphyra yezoensis was studied by enzymatic hydrolysis.In monogalactosyl diacylglycerol, icosapentaenoic acid was amajor fatty acid at both the sn-1 and sn-2 positions of theglycerol moiety, whereas palmitic acid was a minor componentat both positions. In digalactosyl diacylglycerol and sulfoquinovosyldiacylglycerol, icosapentaenoic and palmitic acids were almostexclusively distributed at the sn-1 and sn-2 positions, respectively.In phosphatidylglycerol, palmitic and trans--13-hexadecenoicacid were exclusively located at the sn-2 position. In phosphatidylcholine,icosapentaenoic acid occurred in both the sn-l and sn-2 positions,whereas palmitic acid was confined to the sn-1 position. Itis suggested that monogalactosyl diacylglycerol in P. yezoensissynthesized in both the cytoplasmic and chloroplastic pathways,while the diacylglycerol moieties of the other chloroplast lipidsare virtually all derived from the chloroplastic pathway. (Received March 7, 1986; Accepted April 6, 1987)     

Fatty acid biosynthesis in the peripheral nervous system of normal and Trembler mice

De novo fatty acid biosynthesis was demonstrated in a particle-free supernatant from normal and Trembler mouse sciatic nerves. In both systems, it required acetyl-CoA and malonyl-CoA, and led chiefly to the formation of free palmitic acid. No palmitoyl-CoA formation was detected. The ability of the cell-free extract of the mutant to form palmitic acid in vitro was greater than that of the control extracts when the results were expressed as the total activity per 100 mg of freshly excised sciatic nerves.     

Rapid and efficient gas chromatographic method for measuring the kinetics of lipase-catalyzed transesterification of phosphatidylcholine

Both n-3 polyunsaturated fatty acids (n-3 PUFA) and phospholipids have a lot of special functions on human body. n-3 PUFA includes α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Among them, ALA is the precursor of EPA and DHA. The synthesis of ALA-containing phospholipids can solve the problems of low content of EPA and DHA in phospholipids and show an increased double effect on human body. At a water activity of 0.33, a rapid and efficient method was used for kinetics of the transesterification of phosphatidylcholine (PC) with α-linolenic acid ethyl ester (ALAEE). The rate equation was obtained using palmitic acid ethyl ester (PAEE) as index for reaction rate and the reaction proved to proceed via a Ping-Pong mechanism without inhibition by both the substrates.     

瑞香狼毒茎叶化学成分研究

新鲜瑞香狼毒(Stellera chamaejasme)茎叶经正已烷提取,脱腊后进行GC-MS-DS联用分析,鉴定出20个化合物。主要成分为正十八烷;正十九烷;2,6,10,14 — 四甲基十六烷;十六烷酸;十六烷酸甲酯;十六烷酸乙酯;9,12,15-十八碳三烯酸甲酯;9,12-+八碳二烯酸;9,12,15-十八碳三烯酸和十八烷酸。     

Use of prodigioza in the overall treatment of chronic osteomyelitis]

Treatment of 188 patients suffering from chronic osteomyelitis of various etiology and localization with prodigiosan, a bacterial lipopolysaccharide favoured an increase in the nonspecific immunobiological reactivity: the phagocytic activity and leucocytic intensity increased, the average titers of iso- and heteroagglutinins, as well as the complementary activity of the serum became higher. The results of the clinico-laboratory studies are indicative of advisable use of prodigiosan in complex therapy of cases with chronic osteomyelitis.     

Characterization of the stimulatory effects of PGF2alpha on the release of arachidonic acid

Fibroblasts derived from a rat carrageenin granuloma were cultured in the presence of radioactive arachidonic acid, palmitic acid and linoleic acid. More than 90% of each labeled fatty acid was incorporated into a phospholipid fraction by the cells in 18 hrs. Arachidonic acid was evenly incorporated into phosphatidylcholine and phosphatidylethanolamine, while both palmitic acid and linoleic acid were almost entirely incorporated into phosphatidylcholine. The position of phosphatidylcholine where the fatty acids were incorporated was different for each fatty acid. The ratio of the amount of fatty acid incorporated into the 2-position to the amount incorporated into the 1-position of phosphatidylcholine for each fatty acid was greater than 90% for arachidonic acid, 2:1 for palmitic acid and 5:1 for linoleic acid. In the case of phosphatidylethanolamine, most arachidonic acid (greater than 90%) was incorporated into the 2-position. PGF2alpha caused the stimulation of arachidonic acid release but not of palmitic acid and linoleic acid from pre-labeled fibroblasts. The serum in the medium was completely replaceable by bovine serum albumin. The effect of PGF2Alpha increased with an increasing concentration of bovine serum albumin, suggesting that serum only acts as a "trap" for released arachidonic acid. The effect of PGF2Alpha was greater than bradykinin, and no synergistic effect was seen, although an additive effect was observed. The effect of PGF2Alpha depended on the concentration of calcium ions under magnesium-supplemented conditions.     

The effect of beta-chloro D-alanine and L-cycloserine on the serine, phosphorus and palmitic acid uptake and metabolism of Tetrahymena lipids

The serine palmitoyltransferase inhibitors beta-chloro-D-alanine and L-cycloserine resulted in the uptake and metabolism of 3H-serine, 3H-palmitic acid and 32P significant alterations in the unicellular Tetrahymena pyriformis GL as compared to the untreated cells. In contrast with the higher eukariotic cells, by these treatments - except 5 mM L-cycloserine - the ceramide formation were not inhibited in Tetrahymena. L-cycloserine inhibited the conversion of phosphatidylserine (PS) to phosphatidyl-ethanolamine (PE) by decarboxylation, and the conversion of PE to phosphatidylcoline (PC) by methylation. The shorter L-cycloserine treatments caused lower, and the longer treatments higher label in glycerophospholipids. beta-chloro-D-alanine resulted in the glycerophospholids higher lipid precursor incorporation both in the shorter and longer treatments. Presumably beta-chloro-D-alanine treatments inhibit the transaminase activity, and the higher concentration (5 and 10 mM) proved to be toxic for Tetrahymena. We found differences between the metabolism of serine and palmitic acid labeled lipids in the beta-chloro-D-alanine and L-cycloserine treated groups. This phenomenon is probably due to a difference in the uptake of phospholipid head group component serine and hydrophobic tail precursor palmitic acid: the incorporation of palmitic acid in Tetrahymena is extremely quick, on the other hand, the uptake of serine is slower, a clear time dependence was measured.     

Formation of ethyl acetate by Kluyveromyces marxianus on whey: studies of the ester stripping

Kluyveromyces marxianus is capable of converting lactose into ethyl acetate offering a chance for an economical reuse of whey. The microbial formation of ethyl acetate as a bulk product calls for an aerobic process and, thus, the highly volatile ethyl acetate is discharged from the aerated bioreactor. This stripping process was modeled and investigated experimentally. The stripping rate was proportional to the gas flow and nearly independent of the stirring rate since the stripping was governed by the absorption capacity of the exhaust gas rather than the phase transfer. Cooling the exhaust gas did not noticeably influence the stripping. One batch experiment is presented in detail to demonstrate the formation of ethyl acetate by K. maxianus DSM 5422 on whey. Further batch experiments showed that a substantial formation of ethyl acetate only occurred when the yeast growth was limited by a lack of trace elements. The highest product yield observed was 0.25 g ethyl acetate per g lactose which is nearly 50% of the theoretical maximum.