Enzymatic synthesis of structured phenolic lipids by incorporation of selected phenolic acids into triolein

The synthesis of structured phenolic lipids by lipase-catalyzed transesterification of selected phenolic acids, including p-hydroxyphenyl acetic, p-coumaric, sinapic, ferulic and 3,4-dihydroxybenzoic acids, with triolein was investigated. The highest enzymatic activity (248?nmol esterified phenolic acid/g solid enzyme/min) and bioconversion (62%) was obtained for the transesterification of p-hydroxyphenyl acetic acid with triolein. In addition, the transesterification of p-coumaric with triolein resulted in a higher enzymatic activity (87?nmol esterified phenolic acid/g solid enzyme/min) and bioconversion (46%) than those obtained for the transesterfication of ferulic and sinapic acids. The results also showed that using p-hydroxyphenyl acetic, p-coumaric and ferulic acids as substrate, the maximum bioconversion of phenolic monoacylglycerols was close to that of phenolic diacylglycerols. Although p-coumaric acid had very low radical scavenging activity (2%) compared to that of ferulic acid (62%), the p-coumaroylated lipids demonstrated a higher scavenging potency (16%) than that of the feruloylated one (10%).     

Cytochrome c oxidase subunit 1 barcode data of fish of the Nayband National Park in the Persian Gulf and analysis using meta-data flag several cryptic species

We provide cytochrome c oxidase subunit 1 (COI) barcode sequences of fishes of the Nayband National Park, Persian Gulf, Iran. Industrial activities, ecological considerations and goals of The Fish Barcode of Life campaign make it crucial that fish species residing in the park be identified. To the best of our knowledge, this is the first report of barcoding data on fishes of the Persian Gulf. We examined 187 individuals representing 76 species, 56 genera and 32 families. The data flagged potentially cryptic species of Gerres filamentosus and Plectorhinchus schotaf. 16S rDNA data on these species are provided. Exclusion of these two potential cryptic species resulted in a mean COI intraspecific distance of 0.18%, and a mean inter- to intraspecific divergence ratio of 66.7. There was no overlap between maximum Kimura 2-parameter distances among conspecifics (1.66%) and minimum distance among congeneric species (6.19%). Barcodes shared among species were not observed. Neighbour-joining analysis showed that most species formed cohesive sequence units with little variation. Finally, the comparison of 16 selected species from this study with meta-data of conspecifics from Australia, India, China and South Africa revealed high interregion divergences and potential existence of six cryptic species. Pairwise interregional comparisons were more informative than global divergence assessments with regard to detection of cryptic variation. Our analysis exemplifies optimal use of the expanding barcode data now becoming available.     

Enhancement of antioxidant enzymes activity and expression of CAT and PAL genes in hazel (Corylus avellana L.) cells in response to low-intensity ultrasound

Induction of antioxidant systems of hazel cells by low-energy ultrasound, the potential role of hydrogen peroxide (H₂O₂) as a signaling molecule in regulation of activity of stress-related enzymes, and expression of catalase (CAT) and phenylalanine ammonialyase (PAL) genes were investigated. Suspension-cultured Corylus avellana L. cells were agitated by an ultrasonic device at 29 kHz with the power of 4 mW/cm², for 8–40 min. The activities of CAT, superoxide dismutase (SOD), and ascorbate peroxidase (APX) of treated cells increased by 4, 1.7 and 7 times of the control ones, respectively. Induction of increase in the expression of CAT gene started 24 h after the treatment with ultrasound. Significant increase also was observed in the expression of PAL gene, 6 h after exposure to ultrasound, which resulted in turn to increase of total contents of soluble phenolics, 24 h of the treatment. Exposure to ultrasound up to 20 min had no adverse effects on cell viability although it slightly increased the accumulation of H₂O₂. However, it is likely that this level of increased H₂O₂ was not deteriorative for hazel cells, but rather triggered antioxidant system and provided hazel cells a sustainable growth after ultrasound treatment.     

Effect of Anatase Nanoparticles (TiO2) on Parsley Seed Germination (Petroselinum crispum) In Vitro

Nano priming is a new method for the increase of seedling vigor and improvement of germination percentage and seedling growth. The experiments to evaluate the effect of different concentrations of nano-anatase on germination parameters of parsley as a completely randomized design with five replications were performed in a tissue culture laboratory of the Department of Horticulture, Shahid Chamran University of Ahvaz. In addition, nano-anatase at four concentrations (10, 20, 30, and 40 mg/ml) was added to the Murashige and Skoog medium. At the end of the experiment, the percentage of germination, germination rate index, root and shoot length, fresh weight of seedlings, vigor index, and chlorophyll content were evaluated. The results showed that an increase in the concentration of nano-anatase caused a significant increase in the percentage of germination, germination rate index, root and shoot length, fresh weight, vigor index, and chlorophyll content of seedlings. The best concentration of nano-anatase was 30 mg/ml.     

Manganese substituted Compound I of cytochrome P450 biomimetics: a comparative reactivity study of Mn(V)-oxo versus Mn(IV)-oxo species

Manganese-oxo porphyrins have been well studied as biomimetic models of cytochromes P450 and are known to be able to catalyze substrate hydroxylation reactions. Recent experimental studies [J.Y. Lee, Y.-M. Lee, H. Kotani, W. Nam, S. Fukuzumi, Chem. Commun. (2009) 704] showed that Mn(V)-oxo porphyrins react rapidly with 10-methyl-9,10-dihydroacridine (AcrH(2)) via a proton-coupled-electron-transfer followed by an electron transfer. In this work, we present a computational study on the reactivity patterns of Mn(V)-oxo and Mn(IV)-oxo with respect to AcrH(2). This study shows that although both oxidants are capable of hydroxylating AcrH(2), the Mn(V)-oxo species is the more active oxidant. We have generalized these observations with thermodynamic cycles that explain the reaction mechanisms and electron transfer processes. For the Mn(V)-oxo mechanism the reactions proceed with a fast spin state crossing from the ground state singlet to the triplet spin state prior to a hydrogen atom transfer followed by another electron transfer. The present results are fully consistent with previous studies on iron-oxo porphyrins and manganese-oxo porphyrins and shows that the interplay of low lying singlet and triplet spin state surfaces influences the reaction mechanisms and kinetics.     

Principal Component Analysis of Time-Related Changes of Some Essential Mineral Contents of Canned Silver Carp (Hypophthalmichthys molitrix) in Different Filling Media

Biological Trace Element Research - The kinetic reaction for changes in some essential mineral contents (iron, zinc, calcium, sodium, and copper) of silver carp canned in sunflower oil, soybean...     

Theoretical investigations of the hydrolysis pathway of verdoheme to biliverdin

Conversion of iron(II) verdoheme to iron biliverdin in the presence of OH(-) was investigated using B3LYP method. Both 3-21G and 6-31G* basis sets were employed for geometry optimization calculation as well as energy stabilization estimation. Calculation at 6-31G* level was found necessary for a correct spin state estimation of the iron complexes. Two possible pathways for the conversion of iron verdoheme to iron biliverdin were considered. In one path the iron was six-coordinate while in the other it was considered to be five-coordinate. In the six-coordinated pathway, the ground state of bis imidazole iron verdoheme is singlet while that for open chain iron biliverdin it is triplet state with 4.86 kcal/mol more stable than the singlet state. The potential energy surface suggests that a spin inversion take place during the course of reaction after TS. The ring opening process in the six-coordinated pathway is in overall -2.26 kcal/mol exothermic with a kinetic barrier of 9.76 kcal/mol. In the five-coordinated pathway the reactant and product are in the ground triplet state. In this path, hydroxyl ion attacks the iron center to produce a complex, which is only 1.59 kcal/mol more stable than when OH(-) directly attacks the macrocycle. The activation barrier for the conversion of iron hydroxy species to the iron biliverdin complex by a rebound mechanism is estimated to be 32.68 kcal/mol. Large barrier for rebound mechanism, small barrier of 4.18 kcal/mol for ring opening process of the hydroxylated macrocycle, and relatively same stabilities for complexes resulted by the attack of nucleophile to the iron and macrocycle indicate that five-coordinated pathway with direct attack of nucleophile to the 5-oxo position of macrocycle might be the path for the conversion of verdoheme to biliverdin.     

Hydrodynamic Analysis and Responsivity Improvement of a Metal/Semiconductor/Metal Plasmonic Detector

Characteristic improvements of photon/plasmon detectors have been the subject of several investigations in the area of plasmonic integrated circuits. Among different suggestions, silicon-based metal-semiconductor-metal (MSM) waveguides are one of the most popular structures for the implementation of high-quality photon/plasmon detectors in infrared wavelengths. In this paper, an integrated silicon-germanium (SiGe) core MSM plasmon detector is proposed to detect λ = 1550 nm with internal photoemission mechanism. Performance characteristics of the new sub-micron device are simulated with a simplified hydrodynamic model. In a specific bias point (V = 3 V and the incident optical power of 0.31 mW), the output current is 404.3 μA (276 μA detection current and 128.3 μA dark current), responsivity is 0.89 A/W, and the 3-dB electrical bandwidth is 120 GHz. Simulation results for the proposed plasmon detector, in comparison with the empirical results of a reported Si-based MSM device, demonstrate considerable responsivity enhancement.