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PubMed1996

Oleyl Oleate and Homologous Wax Esters Synthesized Coordinately from Oleic Acid by Acinetobacter and Coryneform Strains

Newly isolated Acinetobacter (NRRL B-14920, B-14921, B-14923) and coryneform (NRRL B-14922) strains accumulated oleyl oleate and homologous liquid wax esters (C30:2-C36:2) in culture broths. Diunsaturated oleyl oleate preponderated in 75 mg liquid wax esters (280 mg lipid extract) recovered from 100-ml cultures of Acinetobacter B-14920 supplemented with 810 mg oleic acid-oleyl alcohol. With soybean oil instead of oleic acid, wax esters (260 mg) were increased to approximately 50% of the lipid extract. Production of wax esters by cultures supplemented with combined fatty (C8-C18) alcohols and acids suggests a coordinated synthesis whereby the exogenous alcohol remains unaltered, and the fatty acid is partially oxidized with removal of C2 units before esterification. Consequently, C8-C18 primary alcohols control chain lengths of the wax esters. Exogenous fatty acids are presumed to enter an intracellular oxidation pool from which is produced a homologous series of liquid wax esters.

Journal Article↗
PubMed1994

Effect of endogenous and inhaled nitric oxide on the ventilation-perfusion relationships in oleic-acid lung injury.

Previous investigations have shown that the ventilation-perfusion (VA/Q) mismatch caused by acute lung injury can be alleviated either by inducing vasodilation in ventilated lung units with inhaled nitric oxide (NO) or by inhibiting the synthesis of endogenous NO, which opposes hypoxic pulmonary vasoconstriction. To determine the effects of a combination of these interventions, we evaluated cardiopulmonary function and VA/Q distributions in 10 dogs with oleic acid-induced lung injury. Each animal received, in random order, zero or 40 ppm of NO in inspiratory gas, with and without intravenous infusion of NG-monomethyl-L-arginine (L-NMMA) (5 mg/kg/h). The multiple inert-gas elimination technique was used to estimate VA/Q distributions. Systemic L-NMMA administration alone did not affect VA/Q inequality and gas exchange, but increased pulmonary and systemic vascular resistance. Inhaled NO improved gas exchange by redistributing blood flow from shunt units to lung units with a nearly ideal VA/Q ratio, without affecting pulmonary or systemic vascular resistance. Improved VA/Q matching and gas exchange was most pronounced when NO was inhaled in the presence of systemic L-NMMA. Inhalation of NO reversed the pulmonary but not the systemic vasoconstriction caused by L-NMMA. These results suggest that endogenous NO release is not limited to hypoxic lung regions in animals with oleic acid-induced lung injury. Inhaled NO reversed L-NMMA-induced pulmonary vasoconstriction and improved VA/Q matching by selectively dilating the pulmonary vasculature in ventilated lung units.

Animals↗
PubMed1989

Hypothermia with and without end-expiratory pressure in canine oleic acid pulmonary edema.

An important goal in managing patients with respiratory failure using mechanical ventilatory support and positive end-expiratory pressure (PEEP) is to optimize tissue oxygen delivery relative to oxygen consumption. To this end, systemic hypothermia has been reported to reduce oxygen consumption. Cooling, however, may antagonize hypoxic pulmonary vasoconstriction and depress cardiac output. To determine whether these potentially adverse effects of cooling on tissue oxygen delivery would outweigh any potential benefits, we studied the effects of systemic hypothermia and end-expiratory pressure on venous admixture, intrapulmonary blood distribution, and oxygenation variables in 40 dogs with oleic acid-induced pulmonary edema of the right lung. The dogs were randomly assigned to four treatment groups of 10 dogs each: normothermia and zero end-expiratory pressure (ZEEP); normothermia and 10 cm H2O PEEP; hypothermia and ZEEP; hypothermia and PEEP. Hypothermia to 31.9 +/- 0.1 degree C (mean +/- SEM) caused no adverse effects on intrapulmonary blood flow distribution (measured by radioactive microspheres) or on venous admixture. Tissue oxygen delivery and arterial oxygenation did not improve with hypothermia, the latter being 109 +/- 13 mm Hg and 70 +/- 8 mm Hg with PEEP and ZEEP, respectively. However, hypothermia significantly reduced oxygen consumption, so that the coefficient of oxygen delivery (i.e., the ratio of oxygen supply to consumption) increased from 2.5 +/- 0.1 to 3.2 +/- 0.2 (p less than 0.01) with ZEEP and from 2.0 +/- 0.1 to 2.6 +/- 0.3 with PEEP (p = 0.016). Thus, although systemic hypothermia failed to improve arterial oxygenation and tissue oxygen delivery, it decreased systemic oxygen demands, thereby improving the oxygen supply-demand balance.

Animals↗
PubMed2000

Biologic variability in mechanical ventilation rate and tidal volume does not improve oxygenation or lung mechanics in canine oleic acid lung injury.

Mechanical ventilation in patients with acute respiratory distress syndrome and acute lung injury (ALI) remains a difficult challenge because of the conflict between maintaining adequate gas exchange and furthering lung injury via overdistention. In a recent study, Lefevre and colleagues (Am. J. Respir. Crit. Care Med. 1996;154: 1567-1572) suggested that mechanical ventilation with natural biologic variability (BV) in breath-to-breath respiratory frequency (f) and VT could reduce lung injury and improve gas exchange without increases in mean airway pressure (Paw) or peak inspiratory pressure (PIP). However, significant differences in cardiac output (CO), Pa(CO(2)), pH, and delivered VT between the treatment groups in their study could have influenced these results. Because of the potential implications of these findings for patient care, we attempted to confirm these findings by Lefevre and colleagues in a canine model of oleic acid-induced lung injury. Eighteen mongrel dogs were anesthetized in the supine position, paralyzed, and mechanically ventilated with 50% O(2) at f = 15 breaths/min, and VT was adjusted to achieve an end-tidal CO(2) of 30 to 35 mm Hg. Lung injury was produced by infusion of 0.06 ml/kg oleic acid solution into the right atrium over a 30-min period. Animals were then randomized to either conventional ventilation at the baseline settings (n = 9) or to BV at the same mean VT and f (n = 9). Both groups received comparable degrees of injury, and hemodynamic and ventilatory parameters were closely matched, with no differences in mean VT, PIP, mean Paw, Pa(CO(2)), pH, CO, pulmonary artery occlusion pressure, or arterial pressure (Pa). However, no differences between the two groups were found in Pa(O(2)), shunt, or static compliance over a 4-h period. When hemodynamic and ventilatory parameters were well matched in a canine model of ALI, BV showed no advantage over conventional ventilation at constant VT and f.

Animals↗
PubMed1996

Plasma lipids, erythrocyte membrane lipids and blood pressure of hypertensive women after ingestion of dietary oleic acid from two different sources.

OBJECTIVE: To study the effect of a diet rich in mono-unsaturated fatty acids (MUFA), from high-oleic sunflower oil (HOSO) and olive oil, on plasma lipids, erythrocyte membrane lipids (including fatty acid composition) and blood pressure of hypertensive (normocholesterolaemic or hypercholesterolaemic) women. METHODS: There were 16 participants who were hypertensive women aged 56.2 +/- 5.4 years. The participants ate a diet enriched with HOSO or olive oil for two 4-week periods with a 4-week washout period before starting the second type of MUFA diet. At entry and during study of each diet, plasma lipids and apolipoproteins were measured by conventional enzymatic methods. Erythrocyte membrane lipid and fatty acid compositions were analysed by means of the latroscan thin-layer chromatography/flame ionization detection technique and by gas chromatography, respectively. Blood pressure was also measured. The statistical analysis was conducted by using Student's two-tailed paired t-test. RESULTS: In both groups of hypertensive patients, there was a significant increase in plasma high-density lipoprotein (HDL) cholesterol concentration after the HOSO or olive oil diets, with regard to baseline. Additionally, a significant decrease in plasma HDL2 cholesterol concentration and an increase in plasma HDL3 cholesterol concentration were evident. The membrane free-cholesterol concentration increased significantly and the phospholipid concentration decreased significantly in erythrocytes after the olive oil diet, though both MUFA diets produced a significant decrease in the concentration of membrane esterified cholesterol. Therefore, the molar ratio of cholesterol to phospholipids was raised significantly in the erythrocyte membrane of hypertensive women after the dietary olive oil, but not after the HOSO diet. In the hypertensive and normo-cholesterolaemic group the HOSO diet significantly increased the content in the erythrocyte membrane of oleic, eicosenoic, arachidonic and docosapentaenoic acids, whereas the olive oil diet increased the content of palmitoleic acid and long-chain polyunsaturated fatty acids of the n-3 family besides, compared with baseline. A significant decrease in linoleic acid was also evident. In the hypertensive and hypercholesterolaemic group, the HOSO diet resulted in significant increases in palmitoleic, oleic, eicosenoic and behenic acids, whereas the olive oil diet enhanced the content of arachidonic, docosapentaenoic and docosahexaenoic acids besides, with respect to baseline. In addition, there was a significant decrease in stearic acid, but only after dietary olive oil was there a decrease in linoleic acid. The most important differences between the two MUFA diets were the increase in n-3 fatty acids and the decrease in the n-6; n-3 fatty acids ratio after dietary olive oil in the erythrocyte membranes of hypertensive patients. Interestingly, a significant reduction in systolic and diastolic blood pressures was only evident after the ingestion of olive oil. CONCLUSION: These data suggest that the beneficial effects of dietary olive oil on the plasma lipids and lipoprotein profile, lipid and fatty acid composition of erythrocyte membrane, and blood pressure in women with untreated essential hypertension are not found equally for the HOSO-rich diet, despite both vegetable oils providing a similar concentration of MUFA.

Aged↗
PubMed1999

A kinetic study on lipase-catalyzed interesterification of soybean oil with oleic acid in a continuous packed-bed reactor.

To provide a mathematical basis for the design and operation of a continuous, packed-bed reactor for the interesterification of soybean oil, soybean oil that contains 22.7% oleoyl and 54.3% linoleoyl moieties as molar acyl moiety composition was interesterified in hexane with oleic acid, using an immobilized sn-1,3-specific lipase (Lipozyme IM) from Mucor miehei. The reaction was carried out in a U-shaped Pyrex glass-made packed-bed reactor at 37 degrees C in the following system: concentration of soybean oil in the feed stream = 12.5 wt%, molar ratio of fatty acid to soybean oil = 3.0, and water content in the feed stream = 1340-2340 ppm. At these water contents, Lipozyme IM gave practically the same catalytic activity, and the content of triacylglycerols in the product oil was 91-94 wt%. Rate equations for the change in oleoyl and linoleoyl moiety compositions in soybean oil were derived and their validity was confirmed experimentally. On the other hand, the catalytic activity of Lipozyme IM decayed in the first-order fashion. Based on these deactivation kinetics, the flow rate of the feed stream is simulated for the operation of a continuous, packed-bed reactor at 37 degrees C that produces an oil of a fixed composition of oleoyl moiety.

Journal Article↗
PubMed2006

Removal of aluminum from some water samples by sorptive-flotation using powdered modified activated carbon as a sorbent and oleic acid as a surfactant.

Bench-scale experiments were conducted in the laboratory, aiming to remove aluminum from water. They were based on using powdered activated carbon (PAC), which was prepared from olive stones generated as plant wastes and modified with an aqueous oxidizing agent as HNO3 as an effective sorbent and oleic acid (HOL) as a surfactant. The main parameters (namely: initial solution pHs, sorbent, surfactant and aluminum concentrations, shaking time, ionic strength and the presence of foreign ions) that influence the sorptive-flotation process were examined. Good results were obtained under the optimum conditions, according to which nearly 100% of aluminum, at pH 7 and at room temperature (approximately 25 degrees C), was removed. The procedure was successfully applied to recover aluminum spiked to some natural water samples. Moreover, a sorption and flotation mechanism is suggested.

Journal Article↗
PubMed1995

Lipid metabolism in pigs fed beef tallow or high-oleic acid sunflower oil.

The objectives of this study were to establish the effects of high-oleic sunflower oil (HOSO) and beef tallow on tissue fatty acids and stearoyl-CoA desaturase activities in swine; and to compare effects of HOSO and tallow on swine plasma triglycerides and lipoprotein-cholesterol fractions. Sixteen gilts were divided into two groups: eight fed a control diet containing 10 g/100 g beef tallow, and eight fed a diet containing 10 g/100 g HOSO. Plasma samples were obtained before feeding began and at 4 weeks and 8 weeks of dietary treatment. Samples were obtained from longissimus dorsi muscle, liver, adipose and duodenal mucosa for the measurement of fatty acid composition and stearoyl-CoA desaturase activity. The HOSO diet increased (P < 0.05) the concentrations (mumol/g wet weight of tissue) of 18:1 and 18:2 (n-6) in adipose tissue. In muscle from pigs fed the HOSO diet, concentrations of 14:0, 16:0, 16:1, 18:0, 18:1, and 18:2 (n-6) decreased (P < 0.05) relative to muscle from pigs fed the beef tallow diet; only 14:0 and 16:1 were reduced in liver by the HOSO diet. Stearoyl-CoA desaturase specific activity [(pmol 7 min-1 mg-1 microsomal protein)] was 40 percent lower, and activity expressed as pmol 7 min-1 g-1 tissue) was 20 percent lower, in adipose tissue of pigs fed HOSO (P < 0.05). No differences due to dietary treatment were observed for desaturase activity from muscle, liver or intestinal mucosa. Plasma triglycerides declined steadily in the tallow-fed pigs, possibly reflecting the lower percentages of liver 18:0 and 18:1 acids, relative to the HOSO-fed pigs. The animals responded similarly to the addition of fat (beef tallow or HOSO) to their diets with increased (P < 0.05) plasma total, LDL- and HDL-cholesterol by 4 weeks of treatment. Total cholesterol, LDL-, VLDL- or HDL-cholesterol were not different between pigs fed beef tallow or HOSO. Thus, differences in fatty acid composition of the diets were sufficient to alter tissue fatty acid composition and adipose tissue desaturase activity, but insufficient to alter plasma lipoprotein cholesterol.

Adipose Tissue↗
PubMed1990

Effect of nifedipine on oxygen delivery in canine asymmetric oleic acid lung injury.

Increasing the ratio of tissue oxygen delivery (DO2) to oxygen consumption can improve the survival of critically ill patients, including those with acute respiratory failure. However, under conditions of ventilation/perfusion mismatch, the use of inotropic or vasodilator drugs to augment cardiac output could, in turn, worsen venous admixture. In a canine model of asymmetric oleic acid-induced pulmonary edema, we examined this possibility by studying the effect of 20 and 40-micrograms/kg doses of parenteral nifedipine on oxygenation variables, venous admixture, and intrapulmonary blood flow distribution. After oleic acid injury, nifedipine caused significant increases in cardiac index by 70% as systemic vascular resistance decreased proportionately by 61%. Stroke volume index (SI) and mean pulmonary arterial pressure increased, while venous admixture and the distribution of intrapulmonary blood flow did not change with nifedipine. However, nifedipine significantly improved the tissue DO2 index so that the coefficient of DO2 increased. Thus, nifedipine significantly increased SI in a dose-dependent manner, thereby improving the tissue oxygen supply-demand balance.

Animals↗
PubMed2005

A comprehensive study of the use of a homologous promoter in antisense cotton lines exhibiting a high seed oleic acid phenotype.

As opposed to first-generation biotechnology products, such as pest-resistant crops and herbicide-resistant crops, second-generation products often utilize plant-derived, homologous or heterologous genes and/or promoters. In this study, we evaluated the ability of a promoter from a gene encoding a major storage protein in cottonseed to drive an antisense sequence of the cotton FAD2 gene to down-regulate the activity of Delta-12 desaturase enzyme in cottonseeds. The oleic acid level in the transgenic cottonseeds approximately doubled from the wild-type level of 15%, with a concomitant decrease in the level of linoleic acid. A more extensive study of one line revealed a higher degree of seed-to-seed variability in the transgenic phenotype. A thorough investigation was conducted to determine the impact of the use of a homologous promoter to drive a transgene on the activity of the endogenous promoter. The results showed that the use of the homologous alpha-globulin B promoter for transgenic purposes did not adversely affect the expression of alpha-globulin B storage protein in cottonseed. The results obtained in this investigation on the use of a homologous promoter and antisense technology will be useful in the design of strategies to alter biosynthetic pathways for nutritional quality improvements and for the production of heterologous proteins of commercial value in seeds.

Journal Article↗
PubMed2006

Seed-specific expression of sesame microsomal oleic acid desaturase is controlled by combinatorial properties between negative cis-regulatory elements in the SeFAD2 promoter and enhancers in the 5'-UTR intron.

The regulation of genes involved in primary lipid metabolism in plants is much less well understood than that in many other pathways in plant biology. In the investigation reported here, we have characterized transcriptional regulatory mechanisms controlling seed-specific FAD2 expression in sesame (Sesamum indicum). FAD2 codes for extra-plastidial FAD2 desaturase, which catalyzes the conversion of oleic acid to linoleic acid. Promoter analysis of the sesame FAD2 gene (SeFAD2) using the beta-glucuronidase (GUS) reporter system demonstrated that the - 660 to - 180 promoter region functions as a negative cis-element in the seed-specific expression of the SeFAD2 gene. Sesame and Arabidopsis FAD2 genes harbor one large intron within their 5'-untranslated region. These introns conferred up to 100-fold enhancement of GUS expression in transgenic Arabidopsis tissues as compared with intron-less controls. Prerequisite cis-elements for the SeFAD2 intron-mediated enhancement of gene expression and the promoter-like activity of SeFAD2 intron were identified. SeFAD2 transcripts were induced by abscisic acid (ABA) in developing sesame seeds, and the - 660 to - 548 and - 179 to - 53 regions in the SeFAD2 promoter were implicated in ABA-responsive signaling. Theses observations indicate that an intron-mediated regulatory mechanism is involved in controlling not only the seed-specific expression of the SeFAD2 gene but also the expression of plant FAD2 genes, which are essential for the synthesis of polyunsaturated fatty acids.

5' Untranslated Regions↗
PubMed2004

A one-pot synthesis of oleic acid end-capped temperature- and pH-sensitive amphiphilic polymers.

A one-pot synthesis of an amphiphilic oleic acid-end capped random poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (2) is reported. In aqueous media, the solubility of 2 was temperature- and pH-sensitive. Both the lower critical solution temperature and critical micelle concentration (CMC) of 2 were pH-dependent. The LCST of 2 was around 35.2 degrees C in acidic buffer solutions (pH=2.00-5.00), and it was increased significantly to around 38.4 degrees C in neutral and alkaline buffer solutions (pH 7.00-11.00). Polymer 2 exhibited a phase transition pH around 6.7, below which the polymer became significantly less water-soluble. The CMC of 2 was 40 mg/l in pH 2.0 buffer solution, and it was increased markedly to 60-67 mg/l in pH 7.0 and pH 11.0 buffer solutions. Micelle solutions of 2 in different pH conditions were prepared by a membrane-dialysis method. In aqueous solution, dynamic light scattering studies revealed that the size of micelles was 50-90 nm with the particle size being larger in acidic solutions. In solid state, transmission electron microscope studies showed that micelles were roughly spherical, their sizes were 25-90 nm and it decreased with the increase of solution pH. The pH-sensitivity of 2 was triggered by the -COOH in the hydrophobic segment. The temperature- and pH-sensitivity of the novel polymeric micelles would make an interesting drug delivery system.

Acrylic Resins↗