Phospholipid molecular profiles in the seed kernel from different sunflower (Helianthus annuus) mutants

Phospholipids are essential components of plant cell membranes whose acyl composition appears to be influenced by oil composition in the sunflower. In the current study, we have determined the diacylglycerol profile of the main phospholipids using phospholipase C degradation and separation of the diacylglycerols by HPLC and GLC. The main polar lipid molecular species were defined in different classes of sunflower kernel: PC, PE, and PI. The proportions of each were determined at different stages of development in order to define the point at which the mutations carried by each sunflower line affected the phospholipid composition of the seeds. The results indicated that modifications to intraplastidial de novo FA synthesis affected the seed phospholipid profile during the whole period of the seed formation, including accumulation and maturation, whereas the influence of mutations in the endoplasmic reticulum desaturases were more readily detected at later stages of development. These results are discussed in terms of the pathways involved in glycerolipid synthesis and phospholipid conversion in sunflower seeds.     

(2S,12Z)-2-Acetoxy-12-heptadecene: Major Sex Pheromone Component of Pistachio Twig Borer, Kermania pistaciella

The sex pheromone of the pistachio twig borer, Kermania pistaciella (Lepidoptera: Oinophilidae), one of the most important insect pests of pistachio, Pistacia vera, in Turkey and Iran, was identified. In gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses of pheromone gland extracts of female K. pistaciella from Turkey, (2S,12Z)-2-acetoxy-12-heptadecene was identified as the major candidate pheromone component. In field experiments in Turkey, lures containing synthetic (2S,12Z)-2-acetoxy-12-heptadecene attracted large numbers of male moths. Its attractiveness was significantly reduced by the presence of the R-enantiomer or of either enantiomer of the corresponding alcohol. (2S,12Z)-2-Acetoxy-12-heptadecene is the first pheromone component identified in the Oinophilidae and the first secondary acetate pheromone component identified in the Lepidoptera. An erratum to this article can be found at     

Varietal and crop year effects on lipid composition of walnut (Juglans regia) genotypes

The FA, unsaponifiable, and volatile constituents of oil from three walnut varieties from two consecutive crop years were studied. The walnut oils (WO) were rich in PUFA and low in saturated FA. The tocopherol fraction consisted mainly of γ-tocopherol. High contents of β-sitosterol were found, together with campesterol and Δ⁵-avenasterol in similar amounts. Methylsterols present in WO were identified as cycloartenol, cyclolaudenol, cycloeucalenol, and 24-methylenecycloartanol. The hydrocarbon fraction was characterized by the predominance of C₁₄–C₂₀ n-alkanes. The major volatiles were aldehydes produced through the linoleic acid oxidative pathway. FA, methylsterols, and some hydrocarbons presented statistically significant differences among varieties. Most of this variation was due to the genotype. The Franquette variety was noteworthy by its higher oil and oleic acid contents. In contrast, tocopherols and volatile compounds showed minor differences among varieties; they were strongly influenced by the crop year. Chemical data were subjected to principal component analysis. The parameters that gave the greatest discrimination between the walnut varieties were oleic and linolenic acids, tetradecane, eicosane, tetracosane, cycloartenol, and 24-methylenecycloartanol. These components presented the major varietal influences and could be useful to determine the identity of walnut genotypes.     

The role of the 11-cis-retinal ring methyl substituents in visual pigment formation

Artificial visual pigment formation from ring-demethylated retinals was studied in an effort to understand the effect that methyl groups on the chromophore cyclohexenyl ring have on the visual cycle. The stereoselective synthesis of the 11-cis-ring-demethylated analogues involves thallium-accelerated Suzuki cross-coupling reactions and highly stereocontrolled Wittig reactions to form key bonds. Only 11-cis-1,1,5-trisdemethylretinal (2) failed to form an artificial pigment, whilst variable pigment-formation yields were determined for the remaining analogues, increasing with the number (and location) of the chromophore hydrophobic ring methyl groups. Our results with the monodemethylated analogues 11-cis-5-demethylretinal (4) and 11-cis-1-demethylretinal (5) show that the C1-2-CH(3) groups are more important for pigment formation than the C5-CH(3) substituent. This is reflected in the absorption maxima of the artificial pigments, with values closer to that of native rhodopsin for 4. Docking studies based on a rhodopsin crystal structure, however, predict a lower pigment stability for 4 than for 5. Gas-phase DFT (B3LYP/6-31G*) computations of the free-ligand geometries, conformational searches about the C6--C7 bond, and docking studies revealed that, although the conformation of bound 5 is close to that of the native chromophore, the ligand needs to overcome the energy cost of shifting the unbound favored 6-s-trans conformation to the bound 6-s-cis form. In addition, the presence of an extra methyl group at C18 (11-cis-18-methylretinal, 7) is tolerated well and adds further stability to the complex, most probably due to increased hydrophobic interactions.     

Chemical analysis of ozonized theobroma fat

Ozonized theobroma fat is used as raw material in the manufacture of pessaries and cosmetic creams. Ozonization of theobroma fat with water was carried out at different applied ozone dosages, and the resultant PV, acid value, iodine value, total hydroperoxide content, and FA content were determined. PV and total hydroperoxide content showed a notable increase with applied ozone dosage up to 35.7 mg/g. Acid value varied slightly from 4.1 to 9.9 mg KOH/g, and the iodine value fell to zero. PV and total hydroperoxide content increased slightly with a higher applied ozone dosage. The comparison of total hydroperoxide measurement using ferrous oxidation in xylenol orange assay and traditional iodometric assay for PV determination showed a significant linear correlation. Small amounts of oleic acid were found in ozonized theobroma fat samples with iodine value equaling zero, which demonstrated that iodine value determination is an inexact assay. During ozonization of theobroma fat, an increase in acid value of 18.9-fold with respect to the initial value was observed owing to decomposition of peroxide.     

Synthesis of Mullite Powders Through a Suspension Combustion Process

This work reports on the synthesis of mullite powders by a suspension combustion process. Aluminum nitrate, as a source of Al, and a colloidal silica suspension, as a source of Si, are used as reagents, and urea serves as the fuel. This colloidal suspension allows a complete mixing of the reactants, thus promoting a core-shell reaction to produce the mullite. The powders obtained need to be treated at a high temperature to form the mullite. However, when ammonium nitrate is also added as a combustion aid, the mullite phase is directly obtained without any further treatment. A chemical reaction involving all these compounds is proposed, and the thermodynamic parameters are calculated in order to predict the temperature reached during the combustion process. The addition of ammonium nitrate reduces the temperature of the reaction by ca. 150°C. Once the conditions for the combustion reaction are optimized, the Al/Si ratio is modified in an attempt to obtain monophasic mullite.     

Prins-type synthesis and SAR study of cytotoxic alkyl chloro dihydropyrans

A series of functionalized tetrahydropyran and dihydropyran derivatives was synthesized by means of a Prins-type cyclization between unsaturated alcohols and several aldehydes. An unprecedented dimer bearing two 4-chloro-5,6-dihydro-2H-pyran scaffolds was obtained in high yield. A panel of three representative human solid tumor cells from diverse origin was used to assess the cytotoxicity of the compounds. Overall, the results show the relevance of the chlorovinyl group in the biological activity, and 2-alkyl-4-chloro-5,6-dihydro-2H-pyrans represent interesting leads for further chemical modifications and biological studies.     

Oxidation of methane in a wide range of pressures and effect of inert gases

The analysis of methane oxidation in a wide range of pressures (0.05–10 atm) demonstrates that the efficiency of CH₃ radicals recombination is of great importance for high selectivity of C₂ hydrocarbons formation. The relative efficiency of different “colliders” assisting the stabilization of exited C₂H*₆ molecules increases in the series: solid surface> Ar> He. The increase of the overall reaction rate upon increasing pressure of the inert gases in the case of catalysts having a higher surface area and more developed pore structure is likely due to the contribution of the surface-induced chain reaction in the volume of pores.     

Characterisation and evolution of a soil affected by olive oil mill wastewater disposal.

A location used for 10 years as an uncontrolled olive oil mill wastewater disposal site is studied in this work. Once it was closed the sedimented solid waste on the soil surface was removed. In order to evaluate the influence upon soil characteristics, morphological aspects and analytical parameters of a soil profile from the affected zone are compared to those of a control soil located near the landfill. The residual contamination levels in the underlying soil are determined. The results show that the wastewater infiltration in the soil has caused carbonate dissolution and redistribution and modifications in pH values, electrical conductivity, nutrient contents, phenolic compounds and biological activity of the horizons. Removal of waste, natural leaching and biological activity, in time, led to an effective decrease in electrical conductivity and phenolic compounds, although residual levels can be important even 2 years later.