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Stereospecificity of microbial hydrations of oleic Acid to 10-hydroxystearic Acid.

We recently described a simple method for ascertaining the stereochemical purities of hydroxy fatty acids (S. H. El-Sharkawy, W. Yang, L. Dostal, and J. P. N. Rosazza, Appl. Environ. Microbiol. 58:2116-2122, 1992) based on the H-nuclear magnetic resonance spectral analysis of diastereomeric S-(+)-O-acetylmandelate esters of hydroxystearates. This report describes the stereochemistries of microbial hydrations of oleic acid to 10-hydroxystearic acid by Nocardia aurantia (also known as Rhodococcus rhodochrous) ATCC 12674, Nocardia restrictus ATCC 14887, Mycobacterium fortuitum UI-53387, Pseudomonas species strain NRRL-2994, Pseudomonas species strain NRRL B-3266, and baker's yeast. 10(R)-hydroxystearic acid isolated from Pseudomonas species strain NRRL-2994 was the standard for use in the H-nuclear magnetic resonance spectral technique to permit simple assignments of the absolute configurations of 10-hydroxystearic acid produced by different microorganisms. While the R. rhodochrous ATCC 12674-mediated hydration of oleic acid gave mixtures of enantiomers 10(R)-hydroxystearic acid and 10(S)-hydroxystearic acid, Pseudomonas species strain NRRL-B-3266 produced optically pure 10(R)-hydroxystearic acid. The remaining microorganisms stereoselectively hydrated oleic acid to 10(R)-hydroxystearic acid containing between 2 and 18% of the contaminating 10(S)-hydroxystearic acid.

Journal Article↗

A diet rich in high-oleic-acid sunflower oil favorably alters low-density lipoprotein cholesterol, triglycerides, and factor VII coagulant activity.

OBJECTIVE: To compare concentrations of factor VII coagulant activity (factor VIIc), fibrinogen, plasminogen activator inhibitor-1, and blood lipids on a saturated fat-rich diet with one rich in monounsaturated fat. DESIGN: Subjects were randomly allocated to two groups. The study design was an ABB/BAA extra-period crossover. One group consumed a diet rich in saturated fatty acid (SFA) with fat making up 20.8% of total energy, for 5 weeks and then one rich in monounsaturated fatty acid (MUFA), with fat making up 20.3% of total energy for 10 weeks. The other group consumed the MUFA diet for 5 weeks followed by the SFA diet for 10 weeks. SUBJECTS/SETTING: Men and women aged 35 to 69 years who were nonsmokers with no chronic illness and not on any medication were recruited to participate. Eighteen subjects were recruited and 15 (5 men, 10 women) completed the community-based study. INTERVENTION: Blood was sampled at the beginning and end point of each 5-week diet period for analysis of coagulation and fibrinolysis factors and blood lipids. Subjects kept 3-day food diaries twice during each of the three diet periods and were weighed on each visit for blood collection. Analysis of plasma fatty acids was used to indicate dietary compliance. MAIN OUTCOME MEASURES: Differences in fasting factor VIIc, fibrinogen, plasminogen activator inhibitor-1, insulin, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoproteins A-1 and B, and plasma oleic acid levels while receiving the SFA diet vs MUFA diet. STATISTICAL ANALYSIS: A general linear model allowing for the ABB/BAA extra-period crossover, was used for each of the outcome measures. RESULTS: Factor VIIc was lower on the MUFA diet ( P <.05) but fibrinogen and insulin concentrations and plasminogen activator inhibitor-1 activity did not differ between diets. Low-density lipoprotein cholesterol ( P <.001) and triglyceride ( P <.01) levels were lower on the MUFA diet compared with the SFA diet. A significant increase in both plasma phospholipid and neutral lipid oleic acid (P <.0001) occurred on the MUFA diet. CONCLUSIONS: Substitution of foods rich in saturated fat with foods rich in high-oleic-acid sunflower oil and margarine has favorable outcomes on blood lipids and factor VIIc. This oil presents another useful source of MUFA for diets aimed at prevention of heart disease.

Adult↗

Band analysis of temperature-dependent near-infrared spectra of oleic acid in the pure liquid state by the analytic geometric approach.

The applicability of the band-stripping and complementary matching method has been demonstrated by the analysis of temperature-dependent near-infrared (NIR) absorption spectra in the 7500-6500 cm(-1) region of oleic acid (cis-9-octadecenoic acid) in the pure liquid state. This method is based on first derivative-second derivative pair (D1-D2) plots and a new concept called the complementary band, cBDi, created by subtracting all the rest of the bands, exclusive of the ith estimated band, eBDi, from an experimental spectrum. The degree of coincidence of both band shapes provides a suitable measure for the quality of fit for each individual component band. It has been confirmed from the present analysis of the NIR spectra of oleic acid measured over a temperature range of 16-79 degrees C that the change of the peak intensity of the component band at around 6915 cm(-1) due to the first overtone of an O-H stretching vibration of the monomer has two transition points around 35 and 55 degrees C. Moreover, the present study has provided new insight into the analysis of temperature-dependent spectral variations of oleic acid. Among the three temperature ranges, 16-35 degrees C, 35-55 degrees C, and 55-79 degrees C, in the first range the band near 6915 cm(-1) shows a slight increase and in the second range it has a linear intensity change with a slope of 0.002 a.u./degree C. In the third range, a rapid increase of the peak intensity is observed. This band exists even at 15 degrees C (just below the melting point) and shows a shift from 6910 to 6915 cm(-1) and a band narrowing from 85 to 80 cm(-1) (full width at half-height) over a temperature range of 16 to 79 degrees C. Furthermore, it has been found that there are two broad bands at around 6835 and 6778.

Mathematics↗

Effects of ricinoleic and oleic acids on the digestive contractile activity of the canine small and large bowel.

Oleic and ricinoleic acids or their trans isomers, elaidic and ricinelaidic acids, were administered intraduodenally and evaluated for their effects on the digestive motor activity of the canine small and large bowel. Four dogs of mixed breed were implanted with duodenal cannulas and extraluminal strain gage transducers along the circular axis of the proximal and mid-jejunum, terminal ileum, and proximal colon. After feeding 200 g of canned dog food to induce continuous contractile activil of isotonic saline was given into the duodenum as a single bolus infusion and recordings were made for a 1-hr period. A 30-ml volume of saline served as control. Administration of each cis fatty acid produced an initial stimulation in jejunal areas of about a 2-min duration followed by a post-stimulatory inhibition. Both the initial stimulation and post-stimulatory inhibition were greater for ricinoleic acid than for oleic acid. Minimal or no effects were produced in ileal or colonic areas. In contrast, the trans isomers produced little or no effect on either the small or large bowel. Alterations in the digestive contractile patterns produced by oral administration of 10 ml of oleic, ricinoleic acid or their respective triglycerides were also tested. Triolein had no effects. Ricinoleic acid and castor oil poduced a brief initial stimulation followed by polonged inhibition of small bowel motor activity. Both cathartics had a mild laxative effect. Digestive motor patterns returned to control approximately 45 min after oleic acid. There was no indication at any time of an initiation of continuous contractile activity after ricinoleic acid or castor oil which could justify the use of the terms irritant of stimulant to describe their actions.

Administration, Oral↗

Does indomethacin affect shunt and its response to PEEP in oleic acid pulmonary edema?

We assessed hemodynamics, lobar perfusion, and shunts at base line 1.5 h after unilobar oleic acid edema, 15 min after indomethacin (10 mg/kg iv), and 15 min after positive end-expiratory pressure (PEEP) (10 cm) in 10 dogs. In 10 additional dogs (control) the same measurements were made but no indomethacin was administered. Shunts of the edematous lobe were: 10.6 +/- 6.3, 54.1 +/- 22.8, 30.8 +/- 16.6, and 12.4 +/- 6.3% for dogs administered indomethacin and 10.9 +/- 4.2, 53.8 +/- 13.1, 72.3 +/- 14.6, and 11.5 +/- 4.1% for the controls. Perfusions (% cardiac output) to the edematous lobe were 27.6 +/- 3.6, 14.6 +/- 2.0, 9.9 +/- 1.5, and 27.9 +/- 2.9% in the dogs administered indomethacin and 27.3 +/- 3.1, 14.0 +/- 1.7, 13.2 +/- 1.3, and 26.9 +/- 2.8% in controls. The decrease in lobar perfusion was similar before indomethacin with a further decrease in lobar perfusion and an increase in lobar vascular resistance 15 min after indomethacin. The increase in vascular resistance of the edematous lobe was three times that of nonedematous lobes after indomethacin (149.6 +/- 76% vs. 58.0 +/- 43%). Indomethacin, therefore, decreases shunt possibly by enhancing alveolar hypoxic vasoconstriction and does not block the improvement in shunt with PEEP.

Animals↗

Identification of oleic acid binding sites in cytolysin A-III from the heteronemertine Cerebratulus lacteus.

We previously demonstrated that binding of oleic acid to Cerebratulus lacteus cytolysin A-III results in aggregation of this monomeric protein to a tetramer, concomitant with an increase in hemolytic activity. In the present study, incubation of cytolysin A-III with [14C]-oleic acid in the presence of a water-soluble carbodiimide results in covalent incorporation of a maximum of two molecules of the fatty acid into the protein. Labeling is restricted to two large tryptic peptides. Sequence analysis of peptide mixtures derived from the labeled protein reveals that the predominant sites of labeling are Lys-31 and Lys-71; the latter site is part of the C-terminal amphipathic helix previously shown to be important for hemolytic activity while the former lies in the other significant hydrophobic region of this largely hydrophilic protein.

Alkylation↗

Metabolism in vivo of [14C]oleic acid and [3H]retinol of lipid-poor and lipid-rich chyle.

[3H]Retinol and [14C]oleic acid labelled fresh chyle was obtained from thoracic duct cannulated rats. The labelled compounds were fed dispersed in either a small amount of egg phosphatidylcholine to produce a lipid-poor chyle, or in a soy bean lipid emulsion to produce a lipid-rich chyle. Small amounts (100 microliters, 24 and 172 micrograms triacylglycerol, respectively) of fresh labelled chyle preparations were injected i.v. into fed recipient animals, which were killed after 10, 20 or 30 min. At 20 min, more [3H]retinyl ester remained in plasma in the rats injected with lipid-rich than in those injected with lipid-poor chyle. The difference was, however, smaller than the difference in the hepatic uptake of 3H. Both the uptake of 3H by the liver and the hydrolysis of [3H]retinyl ester after the uptake, was faster in the group that had been injected with the lipid-poor chyle. The 3H/14C ratios of the serum and liver lipids in relation to that of the injected material did not differ between the two groups, indicating that the proportion of the [14C]triacylglycerol that underwent hydrolysis before clearance of remnants by the liver did not differ. Particularly in the heart, but also in adipose tissue, lungs and kidneys the 3H radioactivity after injecting lipid-rich chyle was highest at 10 min and then decreased with time, being similar in the two groups at 30 min. The results suggest that the formation of remnants from lipoproteins formed after a fat meal requires a longer time for the interaction with endothelial-bound lipoprotein lipase. The uptake by the spleen was also 6-9-fold higher than in the group receiving lipid-poor chyle, indicating that the reticuloendothelial system participates in the metabolism of chyle lipoproteins after a fat meal.

Adipose Tissue↗

Continuous versus pulsatile pulmonary hemodynamics in canine oleic acid lung injury.

Pulmonary hypertension occurs commonly in the acute respiratory distress syndrome (ARDS), but associated right ventricular failure is relatively rare. We tested the hypothesis that this apparent contradiction is explained by a peripheral location of the increased pulmonary vascular resistance (Rpva). Experimental ARDS was induced in eight dogs by injection of oleic acid (0.07 ml/kg). Changes in Rpva were evaluated by measurements of pulmonary artery pressure (Ppa) at several levels of flow (Q), which was altered by manipulation of venous return. The analysis of Ppa decay curves after arterial balloon occlusion was used to partition Rpva into arterial and venous segments. Right ventricular afterload was evaluated by determination of pulmonary vascular impedance (Zpva), which was calculated from spectral analysis of Ppa and Q waves. Oleic acid lung injury was associated with an increase in both the slope and the extrapolated pressure intercept of Ppa/Q plots, no change in the partitioning of Rpva, no change in time-domain indices in wave reflection or in pulmonary arterial compliance, and a decrease in both the characteristic impedance and pulsatile component of total right ventricular hydraulic load. We conclude that the site of increased Rpva in oleic acid lung injury is the smallest pulmonary arterioles, which, together with a decreased characteristic impedance, contributes to minimize right ventricular afterload.

Animals↗

Preparation of inside-out vesicles from erythrocyte membranes inactivates the pathway for oleic acid incorporation into phospholipid.

The pathway for membrane phospholipid fatty acid turnover in situ may be important in the regulation of the composition and turnover of the lipid microenvironment of membrane proteins. This pathway has been characterized further by studying the activation and incorporation of [9,10(n)-3H]oleic acid and transesterification of [1-14C]oleoyl-CoA into membrane phospholipids by isolated erythrocyte membrane ghosts and inside-out vesicles derived from these ghosts. Erythrocyte ghosts and sealed vesicles of defined orientation prepared from them have been widely employed in studies of the function of membrane proteins, particularly those which mediate the transport of ions and sugars. Preparation of inside-out vesicles from ghosts by exposure to alkaline hypotonic conditions results in elution of some membrane proteins but no loss of membrane phospholipid. Compared to ghosts, the ability of inside-out vesicles to activate and incorporate [9,10(n)-3H]oleic acid into phospholipid is diminished by over 90% and the ability of inside-out vesicles to transesterify [1-14C]oleoyl-CoA to phospholipid is diminished by over 50%. These findings indicate that exposure of erythrocyte membranes to the alkaline hypotonic conditions required for inside-out vesicle preparation results in loss or inactivation of both acyl-CoA ligase and acyl-CoA-lysophospholipid acyltransferase activities. This lability of the enzymes for in situ phospholipid fatty acid turnover should be considered in the design and interpretation of studies concerned with elucidation of the relationship between phospholipid fatty acid turnover and the regulation of membrane protein function in this membrane preparation.

1-Acylglycerophosphocholine O-Acyltransferase↗

Synthesis of enantiopure non-natural alpha-amino acids using tert-butyl (2S)-2-[bis-(tert-butoxycarbonyl)amino]-5-oxopentanoate as key-intermediate:the first synthesis of(S)-2-amino-oleic acid.

A general method for the synthesis of enantiopure non-natural alpha-amino acids is described. The key intermediate tert-butyl (2S)-2-[bis(tert-butoxycarbonyl)amino]-5-oxopentanoate was obtained from l-glutamic acid after suitable protection and selective reduction of the gamma-methyl ester group by DIBALH. Wittig reaction of this chiral aldehyde with various ylides led to a variety of delta,epsilon-unsaturated alpha-amino acids. This methodology was applied to the synthesis of (S)-2-amino-oleic acid.

Amino Acids↗

The role of cytochrome b5 in delta 12 desaturation of oleic acid by microsomes of safflower (Carthamus tinctorius L.).

The electron donors for the membrane-bound fatty acid desaturases of higher plants have not previously been identified. In order to assess the participation of cytochrome b5 in microsomal fatty acid desaturation, the cytoplasmic domain of microsomal cytochrome b5 was purified from Brassica oleracea, and murine polyclonal antibodies were prepared. The IgG fraction from ascites fluid inhibited 62% of NADH-dependent cytochrome c reduction in safflower (Carthamus tinctorius L.) microsomes. These antibodies also blocked desaturation of oleic acid to linoleic acid in lipids of C. tinctorius microsomes by 93%, suggesting that cytochrome b5 is the electron donor for the delta 12 desaturase.

Carbon Radioisotopes↗

Neurotensin stimulates [3H]oleic acid translocation across rat small intestine.

The effect of neurotensin (NT) on the translocation of intraluminally administered lipid across the duodenum as well as across the entire length of the small intestine was studied in the rat. In the first series of experiments, the appearance in the lymph of [3H]oleic acid instilled as a bolus into a segment of the duodenum was followed for 3 h. Infusion of NT (0.6 pmol X kg-1 X min-1) via the superior mesenteric artery resulted in a significant increase in the appearance of label in the lymph when compared with saline infusion (17.3 +/- 3.1 vs. 8.6 +/- 1.4%, P less than 0.01, respectively). In the second series of experiments, lipid was infused into the entire length of the small intestine over 4 h, and the accumulation of label in the lymph was measured. The infusion of NT (1.0 pmol X kg-1 X min-1) into the femoral vein also significantly increased the appearance of label when compared with animals infused with saline (49.0 +/- 2.0 vs. 34.2 +/- 5.2%, P less than 0.05, respectively). In this study, the specific activity of the triglyceride recovered in the lymph was higher in the rats given NT than in the controls (P less than 0.05). No significant changes in lymph flow were observed as a consequence of NT infusion. These results indicate that NT infusion into the circulation increases the translocation of oleic acid from the intestinal lumen into the lymph of rats.

Animals↗

[Prophylactic effects of Salvia miltiorrhizae and ligustrazine on experimental respiratory distress syndrome induced by oleic acid in rats].

The prophylactic effects of Salvia miltiorrhizae and ligustrazine on experimental respiratory distress syndrome (RDS) in Wistar rats were observed and compared with the dexamethasone. Sixty-two male rats weighing 194.68 +/- 20.40 g (M +/- SD) were used in this experiment. The rats were randomly divided into five (A-E) groups. Group A was given normal saline 0.1 ml/kg alone and group B oleic acid 0.1 ml/kg; both were injected in tail vein, and the latter produced typical RDS. Group C, D, E were injected intraperitoneally with agents of dexamethasone 2 mg/kg, Salvia miltiorrhizae 1.5 g/kg, and ligustrazine 20mg/kg, respectively, 15 minutes before oleic acid intravenous injection. All of the animals were sacrificed quickly 6 hours after injections and lung tissues were taken and examined with light and electronic microscope. The results showed that all of these medicines could minimize the lesions caused by oleic acid. Lung/body index was reduced. Prophylactic effects of Salvia miltiorrhizae and ligustrazine were similar to dexamethasone. The authors considered that preventive use of Salvia miltiorrhizae or ligustrazine could protect the lung from the development of RDS.

Animals↗

Comparison of the effects of medium-chain triacylglycerols, palm oil, and high oleic acid sunflower oil on plasma triacylglycerol fatty acids and lipid and lipoprotein concentrations in humans.

Although medium-chain triacylglycerols (MCTs, composed of medium-chain fatty acids 8:0 and 10:0) have long been described as having neutral effects on serum cholesterol concentrations, experimental evidence supporting this claim is limited. In a randomized, crossover, metabolic-ward study, we compared the lipid effects of a natural food diet supplemented with either MCTs, palm oil, or high oleic acid sunflower oil in nine middle-aged men with mild hypercholesterolemia. Rather than having a neutral effect, MCT oil produced total cholesterol concentrations that were not significantly different from those produced by palm oil (MCT oil: 5.87 +/- 0.75 mmol/L; palm oil: 5.79 +/- 0.72 mmol/L) but significantly higher than that produced by high oleic acid sunflower oil (5.22 +/- 0.52 mmol/L). Low-density-lipoprotein (LDL)-cholesterol concentrations paralleled those of total cholesterol. MCT oil tended to result in higher triacylglycerol concentrations than either palm oil or high oleic acid sunflower oil, but this difference was not significant. There were no differences in high-density-lipoprotein cholesterol concentrations. The palmitic acid and total saturated fatty acid content of plasma triacylglycerols in the MCT-oil diet was not significantly different from that in the palm oil diet. On the basis of percentage of energy, this study suggests that medium-chain fatty acids have one-half the potency that palmitic acid has at raising total and LDL-cholesterol concentrations.

Aged↗

Inhibition of the activity of human leukocyte elastase by lipids particularly oleic acid and retinoic acid.

The effect of various natural hydrophobic lipids on the in vitro and in vivo activity of human leukocyte elastase has been examined. In vitro studies using 2 different substrates indicated that fatty acids inhibit human leukocyte elastase activity, with maximum inhibition observed with oleic acid. Triolein, cholesterol, and beta-carotene caused little inhibition. The presence of a carboxyl group appears important since retinoic acid but not retinol also inhibited activity. In vivo studies of an emphysema model in mice indicated that intrapulmonary instillation of oleic or retinoic acid reduced lung injury caused by human leukocyte elastase. The possibility of using these compounds to diminish elastolytic damage in emphysema is raised.

Animals↗

Transcriptional regulation of the Bacillus subtilis bscR-CYP102A3 operon by the BscR repressor and differential induction of cytochrome CYP102A3 expression by oleic acid and palmitate.

The adjacent yrhI and yrhJ genes were identified by the Bacillus subtilis genome sequencing project. We now report that yrhJ (renamed CYP102A3) encodes a cytochrome P450 and that yrhI (renamed bscR) encodes a repressor that negatively regulates the transcription of the bscR-CYP102A3 operon. The transcriptional initiation site of bscR has been mapped by primer extension analysis. An 18-bp perfect palindromic sequence centered 65.5 bp downstream from the transcriptional initiation site of bscR has been identified as the binding site for BscR by gel mobility shift assays. Base substitutions in the 18-bp inverted repeat resulted in derepression of the bscR-xylE transcriptional fusion in vivo. bscR-xylE fusion studies and Northern blot analysis revealed that oleic acid and palmitate could induce the expression of the bscR-CYP102A3 operon to a considerable extent. However, only oleic acid was capable of preventing the binding of BscR to its operator DNA in vitro, suggesting that the induction of CYP102A3 expression by oleic acid and palmitate in B. subtilis might be mediated through different mechanisms.

Amino Acid Sequence↗

Oleic acid is elevated in cell membranes during rapid cold-hardening and pupal diapause in the flesh fly, Sarcophaga crassipalpis.

The integrity of cellular membranes is critical to the survival of insects at low temperatures, thus an advantage is conferred to insects that can adjust their composition of membrane fatty acids (FAs). Such changes contribute to homeoviscous adaption, a process that allows cellular membranes to maintain a liquid-crystalline state at temperatures that are potentially low enough to cause the membrane to enter the gel state and thereby lose its ability to maintain homeostasis. Flesh flies (Sarcophaga crassipalpis) were subjected to two experimental conditions that elicit low temperature tolerance: rapid cold-hardening and diapause. FAs were isolated and analyzed using gas chromatography-mass spectrometry. FAs changed in response to both rapid cold-hardening and diapause. In response to rapid cold-hardening (8 h at 4 degrees C), the proportion of oleic acid (18:1n-9) in pharate adults increased from 30% to 47% of the total FA pool. The proportion of almost every other FA was reduced. By entering diapause, pupae experienced an even greater increase in oleic acid proportion, to 58% of the total FA pool. Oleic acid not only promotes membrane fluidity at low temperature but also allows the cell membrane to maintain a liquid crystalline state if temperatures increase.

Acclimatization↗