MODIFIED ETHANOL INJECTION METHOD FOR LIPOSOMES CONTAINING β-SITOSTEROL β-D-GLUCOSIDE

A modified ethanol injection method for liposomes containing soybean phosphatidylcholine (SPC), cholesterol (Ch), β-sitosterol β-D-glucoside (Sit-G) and oleic acid (OA) was developed, that can produce homogeneous unilamellar liposomes without the use of sonication and dialysis. In this method, water is poured into a concentrated lipid-ethanol solution and then ethanol is removed in an evaporator. Dilution with water causes spontaneous formation of small and homogenous unilamellar vesicles from micellar aggregate. The size of liposomes can be controlled by the ratio of ethanol to water. OA and Sit-G were distributed at the surface of liposomes and were recognized by Concanavalin A, respectively. This easy and quick method for preparation of liposomes may be applicable in many areas.     

Schistosoma mansoni: Assessment of effects of oleic acid,cercarial age and water temperature on parasite-host attraction

Although the lifecycle of Schistosoma spp. and pathophysiology of schistosomiasis have been established, the mechanism by which cercariae find their host is not well understood. Speculatively, host infection by random and accidental host contact is not as biologically plausible as a biochemical mechanism of mammalian attraction. A few studies have indicated that biochemical cues and temperature gradients may play a role in host identification, attraction and attachment triggers. This study aimed to elucidate these mechanisms more specifically through evaluation of biochemical, age and temperature influences leading to Schistosoma mansoni cercariae attraction and attachment behaviors. Oleic acid, a common unsaturated free fatty acid in the outer layer of human skin, was tested for cercariae attraction across biologically relevant concentrations. Influence of media type (beeswax, nail varnish and agar), age-dependent behavior variability and environmentally appropriate temperatures (22 and 30 °C) were also evaluated. Results indicated that oleic acid at concentrations of 0.3, 0.9 and 1.8 g/mL in beeswax significantly increased median attachment to media (median attachment of 7.50%, 4.20% and 3.71%, respectively, P < 0.001), compared with plain beeswax, with maximal attachment of 30.30% at 0.3 g/mL of oleic acid. In media containing 0.3 g/mL of oleic acid, cercarial attachment was highest for freshly emerged cercariae to 5 h post-emergence, with a significant decrease in attachment behavior at 10 h post-emergence (P < 0.01). Aquatic temperature at which cercariae were exposed to media did not yield significant results (P value >0.05). Biochemical, age and environmental factors influencing cercarial host attraction and attachment behavior have been elucidated by this study. This information will inform further development of devices for environmental surveillance and potentially improve cercarial exposure prevention strategies.     

Improved production of citric acid by Yarrowia lipolytica using oleic acid as the oxygen‐vector and co‐substrate

Yarrowia lipolytica is able to secrete large amounts of citric acid (CA), which is greatly affected by the dissolved oxygen concentration (DOC) in the fermentation medium. In this study, oleic acid was selected as oxygen‐vector to improve DOC during CA fermentation. When 2% (v/v) of oleic acid was added to the culture broth, higher DOC (>42.1%) was determined throughout the CA synthesis phase. The yield of CA reached a maximum of 32.1 g/L (25.4% higher than the control) and the biomass was 8.8 g/L. The substrate uptake rate, products formation rate and key enzyme activities were also determined, and the results indicated that CA synthesis was strengthened with oleic acid addition. Furthermore, it was detected that oleic acid could be assimilated by the cells, which means that oleic acid could be served both as oxygen‐vector and co‐substrate for CA synthesis by Y. lipolytica. In a bioreactor with working volume of 3 L, the highest concentration of CA reached to 36. 4 g/L in the presence of 2% (v/v) oleic acid after 192 h of fermentation. These results confirmed that oleic acid could be applied in the large‐scale production of CA by Y. lipolytica.     

Impact of Surface Active Compounds on Iron Catalyzed Oxidation of Methyl Linolenate in AOT–Water–Hexadecane Systems

Edible oils contain minor surface active components that form micro-heterogeneous environments, such as reverse micelles, which can alter the rate and direction of chemical reactions. However, little is known about the role of these micro-heterogeneous environments on lipid oxidation of bulk oil. Our objective was to evaluate the ability of water, cumene hydroperoxide, oleic acid, and phosphatidylcholine to influence the structure of reverse micelles in a model oil system: sodium bis(2-ethylhexyl) sulfosuccinate (aerosol-OT; AOT) in n-hexadecane. The influence of reverse micelle structure on iron catalyzed lipid oxidation was determined using methyl linolenate as an oxidizable substrate. The size and shape of the reverse micelle were investigated by small-angle x-ray scattering, and water contents was determined by Karl Fischer titrations. Lipid hydroperoxides and thiobarbituric acid reactive substances were used to follow lipid oxidation. Our results showed that AOT formed spherical reverse micelles in hexadecane. The size of the reverse micelles increased with increased water or phosphatidylcholine concentration, but decreased upon addition of cumene hydroperoxide or oleic acid. Iron catalyzed oxidation of methyl linolenate in the reverse micelle system decreased with increasing water concentration. Addition of phosphatidylcholine into the reverse micelle systems decreased methyl linolenate oxidation compared to control and reverse micelles with added oleic acid. These results indicate that water, cumene hydroperoxide, oleic acid, and phosphatidylcholine can alter reverse micelle size and lipid oxidation rates. Understanding how these compounds influence reverse micelle structure and lipid oxidation rates could provide information on how to modify bulk oil systems to increase oxidative stability.     

Development of high oleic and low linoleic acid transgenics in a zero erucic acid Brassica juncea L. (Indian mustard) line by antisense suppression of the fad2 gene

A zero erucic acid (C22:1) line of Brassica juncea (VH486), adapted to the agronomic conditions of Northern India, has been modified for its fatty acid composition in the seed oil with antisense constructs using the sequence of fad2 gene of B. rapa. The full-length B. rapa fad2 cDNA sequence was determined by 5 and 3 RACE of a partial sequence available in the EST database. Construct pASfad2.1 contained 315 to 1251 bp and construct pASfad2.2 contained 1 to 1251 bp fragment of the fad2 gene, both in antisense orientation, driven by a truncated napin promoter. Analysis of the levels of linoleic acid (C18:2) in the BC1 seeds of single-copy transgenics showed that the construct pASfad2.2 gave better suppression of the fad2 gene as compared to the construct pASfad2.1. The BC1 transgenic seeds containing the pASfad2.2 construct segregated into two distinct classes of C18:2>20% (putative null homozygotes) and C18:2<20% (putative heterozygotes) in a 1:1 ratio, while the T1 seeds segregated into three classes, C18:2>20%, C18:2 between 12% and 20%) and C18:2<12% (putative homozygotes) in a 1:2:1 ratio. Putative homozygous T1 seeds (C18:2<12% analyzed by the half-seed method) of four of the transgenic lines were grown to establish T2 homozygous lines. These had ca. 73% C18:1 and 8 to 9% each of C18:2 and C18:3 (-linolenic acid) fractions in comparison to ca. 53% C18:1, 24% C18:2 and 16% C18:3 in the parental line VH486.     

A dominant mutation for high oleic acid content in sunflower (Helianthus annuus L.) seed oil is genetically linked to a single oleate-desaturase RFLP locus

Pervenets is a sunflower mutant with a seed oil oleic acid content greater than 65%. It was obtained after mutagenesis treatment on VNIIMK 8931. Several commercial varieties derived from Pervenets and breeding materials with a high oleic acid content have been marketed. However, the genetics of this trait are still not fully understood by breeders. To characterize the Pervenets mutation, we studied RFLP in relation to high oleic acid content. We performed diversity analyses on 239 genotypes with cDNA sequences coding for 9- and 12-desaturases as probes. The 12 RFLPs enabled us to identify at least two independent loci. One 12 RFLP allele (12HOS) was strictly correlated to high oleic acid content, whereas no correlation was found between 9-desaturase polymorphism and high oleic acid content. These results enabled to us estimate the genetic distance between the marker and the Pervenets mutation loci. An F₂ segregating population of 107 plants confirmed the correlation between high oleic acid content and 12HOS, indicating tight genetic linkage. The nature of the Pervenets dominant mutation and the complexity of the high oleic acid content trait are discussed.     

Expressed variants of Δ12-fatty acid desaturase for the high oleate trait in spanish market-type peanut lines

Increasing the oleic to linoleic acid ratio (O/L) in peanut has positiveeffects on peanut quality and its nutritional value. ¹²-Fattyacid desaturases (¹²-Fad) have been targeted as logicalcandidates controlling the high oleate trait. A previous study using genomicDNA identified an insertion and a polymorphism resulting in an amino acid changeassociated with the high oleate trait in Spanish-type peanut cultivars. Theobjectives of this research were to use RT-PCR to confirm that the SingleNucleotide Polymorphims (SNPs) identified by analysis of genomic DNA wereexpressed, and to determine if expression patterns for ¹²-Fadwere the same in both seeds and leaves. A polymorphic region of the¹²-Fad containing a series of nucleotide changes wasamplified, cloned, and sequenced from mRNA of 155 clones of two parental linesand their independent derived backcross lines (IDBLs). The latter differed intheir oleic to linoleic ratio. Data indicated that the Ainsertion and the amino acid change were expressed in both leaf and seed tissue of thehigh and low-intermediate O/L genotypes. It is postulated that several copiesof the ¹²-Fad are present in the genome. It is reasonable toconclude that total activity, and ultimately the O/L ratio, is dependent on thenumber of functional copies. The results provide the basis for an assay toscreen for the high O/L ratio at the molecular level. We also report thepresence of another isozyme of ¹²-Fad with high homology tosoybean isozyme 2 that was expressed in seeds. These authors contributed equally to this work     

龙生型高油酸花生种质油酸亚油酸含量及其比值的遗传分析

应用植物数量性状主基因+多基因混合遗传模型,对2个龙生型花生高油酸种质与低油酸珍珠豆型品种杂交组合F2的油酸、亚油酸含量及其比值(O/L值)进行遗传分析,结果表明:花生油酸、亚油酸含量的遗传均表现为1对主基因加性-显性模型。控制油酸含量主基因的加性、显性效应值和遗传率在组合I中分别为8.6281、-2.0164和65.26%,在组合II中则分别为10.6638、1.0652和71.39%;控制亚油酸含量主基因的加性、显性效应值和遗传率在组合I中分别为8.0327、1.2858和73.64%,在组合II中则分别为9.0885、-1.0826和71.59%。O/L值的遗传表现为2对主基因加性-显性-上位性模型。2对主基因的加性效应值分别为0.6855、0.6814(组合I)和1.6842、0.8835(组合II),显性效应值分别为-0.6838、0.024(组合I)和-1.6559、-0.5127(组合II);加性×加性效应(i)、加性×显性效应(jab)、显性×加性效应(jba)、显性×显性效应(l)分别为0.6812、0.024、-0.6803、-0.0244(组合I)和0.8822、-0.5124、-0.8594、0.496(组合II);组合I、II主基因遗传率分别为82.57%和88.64%。     

Nitric oxide-independent lipid metabolism in RAW 264.7 macrophages loaded with oleic acid

The role of nitric oxide (NO) in the regulation of lipogenesis and lipolysis in RAW 264.7 macrophages loaded with oleic acid (OA) was investigated in this paper. Magnolol stimulated full lipolysis without affecting NO levels. Both inhibition and elevation of NO production in OA-loaded macrophages did not induce lipolysis. Besides, lipopolysaccharide (LPS)-induced increased accumulation of lipid droplets was not reduced by down-regulation of NO levels. Moreover, incubation of macrophages with sodium nitroprusside (SNP), an NO donor, stimulated significant NO production without altering the lipid droplet accumulation. All these results clearly demonstrate that NO is not involved in the modulation of lipid metabolism in macrophages loaded with OA.     

Spatial variation in the fatty acid composition of elaiosomes in an ant-dispersed plant: Differences within and between individuals and populations

Euphorbia characias is a common myrmecochorous plant of the western Mediterranean Basin whose seeds are dispersed by ants following fruit explosion. The variation in elaiosomes’ fatty acid composition of this species was studied at three hierarchical levels (sub-individual, individual and population) in four populations from the Iberian Peninsula. We found that differences in fruit location on the inflorescence do not seem to influence the fatty acid composition of elaiosomes, providing to each propagule an equal chance of being dispersed. However, significant differences in elaiosome fatty acid composition between individuals and populations were found for most of the compounds identified. The content of oleic acid, a key mediator in the ant–seed interaction, differed widely between populations, probably reflecting geographic variations in co-adaptation between plants and their dispersers. The finding that the fatty acid composition of E. characias elaiosomes is distinct from that of the seed itself, but very similar to that of elaiosomes from unrelated species, reinforces the idea of convergent evolution in the chemical composition of these structures.