Calcium-independent phospholipase A2 (iPLA2) belongs to the group VI family of phospholipase superfamily (PLA2) that catalyses the hydrolysis of glycerophospholipids at the sn-2 ester bond, producing unesterified fatty acids and 2-lysophospholipids. Research interests on iPLA2 have not been as significant as those on secretary PLA2 and cytosolic PLA2. However, more efforts have been made recently on understanding the expression, regulation and biological function of iPLA2. iPLA2 plays important roles in several biological processes, including signal transduction, phospholipid remodelling, eicosanoid formation, cell proliferation, cell differentiation and apoptosis. Modulation of iPLA2 activity can have prominent effects on cellular metabolism, central nervous system and cardiovascular functions. Thus, dysregulation iPLA2 can play a vital role in the pathogenesis of several diseases. The aim of this review is to provide the current understanding of the structure, function and regulation of group VI iPLA2 and highlight its potential mechanisms of action in mediating several neurological disorders and cancer.
We investigated the effects of ultrasound treatment on cellulase adsorption and lignocellulose hydrolysis. The activity of cellulase remained constant upon low-power ultrasound treatment (<120 W) and decreased using high-power ultrasound (>280 W). Oscillating cellulase adsorption occurred upon ultrasound treatment with any intensity. The maxima for desorption and adsorption were 41.9 and 83.1%, respectively, during 1 h of 90 W ultrasound treatment at 50 °C. A comparison between the short-time with long-time ultrasound experiments indicated that ultrasound treatment tended to desorb cellulase from substrate. However, ultrasound treatment also led to further surface erosion of biomass, which increased cellulase accessibility. These joint actions of ultrasound treatment induced the oscillating adsorption of cellulase. The increase in cellulase accessibility caused by ultrasound treatment led to a significant enhancement in lignocellulose hydrolysis.
Hydrogen dielectric-barrier discharge (H2-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H2-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H2-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer–Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H2-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H2-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.
The selection and design of an optimal solvent for extractive distillation require reliable vapour–liquid phase equilibrium data and knowledge of extraction mechanisms. Compared with time-consuming experiments, molecular simulation presents great potential in research on the properties of fluids. Therefore, in this work, Gibbs ensemble Monte Carlo was applied to successfully predict the vapour–liquid phase equilibrium data of binary and ternary systems containing benzene, thiophene and N, N-dimethylformamide (DMF) at P = 101.3 kPa. The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene, whereas the OPLS potential model was selected for DMF. The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model. A good agreement was obtained, which corroborated the validity of the potential models. In addition, the extraction mechanism was explored by radial distribution function (RDF) of the liquid-phase structure. The RDFs showed that thiophene and benzene shared a similar liquid-phase structure because of the intermolecular interaction. The distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene, which may be responsible for the extraction effect of DMF.
In this study, we used a simple impregnation method to prepare Fe–Ce–O x catalysts and tested them regarding their low-temperature (200–300 °C) selective catalytic reduction (SCR) of NO using NH3. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO2/H2O resistance of the catalysts. The results showed that the FeCe(1:6)O x (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O x catalyst had the highest NO conversion with an activity of 94–99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h−1. The NO conversion for the FeCe(1:6)O x catalyst also reached 80–98% between 200 and 300 °C at a space velocity of 204,000 h−1. In addition, the FeCe(1:6)O x catalyst demonstrated good stability in a 10-h SCR reaction at 200–300 °C. Even in the presence of SO2 and H2O, the FeCe(1:6)O x catalyst exhibited good SCR performance.
ZSM-5 zeolite prepared by a hydrothermal method with the addition of seeds was treated with different concentrations of NaOH. The obtained samples were characterized by XRD, N2 adsorption, NH3-TPD, FT-IR, SEM, and studied in the catalytic performance of the hydration of cyclohexene to cyclohexanol. The characterization results showed that with the increase of NaOH concentration, the crystallinity of the treated samples decreased monotonously, and the acid sites of ZSM-5 zeolites first increased and then decreased, while more mesopores formed inside the ZSM-5 zeolites. The experimental results of catalytic performance showed that cyclohexene conversion can be improved through introducing the mesopores and enhancing the acidity of ZSM-5 with the NaOH treatment at a low concentration. The highest cyclohexene conversion of 12.8% was obtained when the concentrations of NaOH solution were in the range of 0.2–0.6 mol/L. The selectivity of cyclohexanol on all samples was higher than 99.6%.
The development of edible coatings has been lauded with respect to their safety and effectiveness. In this study, we researched the effects of edible coatings (2% CaCl2, 1% chitosan and 1% pullulan) on the nutrient content and antioxidant abilities of jujube (Zizyphus jujuba Miller cv. Dongzao). Using the new analysis technique for order of preference by similarity to ideal solution (TOPSIS), we evaluated the effects of these coatings. Compared with the control fruit group, test results showed that coating treatment significantly delayed fruit senescence. Specifically, CaCl2 treatment not only maintained fruit storage quality and antioxidant activity but also restrained the production and accumulation of malondialdehyde in jujube. Chitosan treatment delayed decreases in secondary metabolites and superoxide dismutase and catalase activity. Pullulan coatings performed better in terms of proanthocyanidin and cyclic adenosine monophosphate (cAMP). We also used TOPSIS to evaluate the preservation effect of different film coatings and found 2% CaCl2 to be the best treatment for jujube, followed by 1% chitosan and 1% pullulan. Based on the appropriate materials and concentration of the film coatings, edible coatings have the potential to retain the quality and antioxidant capacity of the Chinese jujube cv. Dongzao.
Carotenoid cleavage dioxygenases (CCDs) are a class of enzymes in plants involved in the biosynthesis of apocarotenoids, such as phytohormones, flavour compounds, and other compounds with yet unknown functions. To date, several CCDs have been functionally characterised in plants, but little is known about the CCD4 members. A carotenoid cleavage dioxygenase 4 gene (LcCCD4) was isolated from the leaves of wolfberry (Lycium chinense) to gain insight into its biological function. Multiple sequence alignment and phylogenetic analyses showed that the deduced amino acid sequence of LcCCD4 shares high homology with that of CCD4 proteins from other plants. Expression analysis using semi-quantitative polymerase chain reaction revealed that LcCCD4 was strongly expressed in leaves and flowers and that the expression level was in accordance with β-carotene concentration. LcCCD4 transcripts in fruits tended to decrease as carotenoids accumulated. Recombinant expression of LcCCD4 cleaved β-carotene to produce β-ionone in in vivo assays. These results show that LcCCD4 is a CCD gene that may be involved in producing aromatic apocarotenoids in leaves and flowers, whereas it may be involved in controlling carotenoid accumulation in fruits.
In this study, we aimed to examine the inhibitory effect of PA003, a Pediococcus acidilactici that produces lactic acid and antimicrobial peptides pediocin, on pathogenic biofilm formation on abiotic surfaces. PA003 and pathogens (Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus and Listeria monocytogenes) were used to evaluate auto-aggregation, hydrophobicity, biofilm formation and biofilm formation inhibition on stainless steel, polyvinyl chloride and glass slides in terms of exclusion, displacement and competition. The results showed the highest auto-aggregation abilities were observed for one of the E. coli strains EAggEC (E58595) and the highest hydrophobic strain was observed with EPEC (E2348/69) (51.9%). The numbers of biofilm cells of E. coli, S. Typhimurium, S. aureus and L. monocytogenes on stainless steel, polyvinyl chloride and glass slide coupons were effectively reduced by approximately 4 log CFU/coupon. These results demonstrate that lactic acid bacteria can be used as an alternative to effectively control the formation of biofilms by food-borne pathogens.
Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation. Initially, the component factors, which influence antifungal substance production, were studied by varying one factor at a time. Starch, soybean cake powder, K2HPO4·3H2O and MgSO4·7H2O were found to have a significant effect on the production of antifungal substances by the traditional design. Then, a Box–Behnken design was applied for further optimization. A quadratic model was found to fit antifungal active substance production. The analysis revealed that the optimum values of the tested variable were starch 84.96 g/L, soybean cake powder 4.13 g/L, glucose 5 g/L, MgSO4·7H2O 1.23 g/L, K2HPO4·3H2O 2.14 g/L and NaCl 0.5 g/L. The test result of 67.44% antifungal inhibition agreed with the prediction and increased by 14.28% in comparison with the basal medium.
Fasudil (HA-1077) is the first small-molecule inhibitor of Rho-kinase and has been employed for clinical treatment of cerebral vasospasm. Hydroxyfasudil, as a metabolite of fasudil, exhibited better activity than fasudil. However, it also suffered from quick metabolisation, weak lipotropy and worse penetration of the blood–brain barrier. Thus, some hydroxyfasudil derivatives such as hydroxyfasudil acetate, hydroxyfasudil phosphate and 1-methoxyfasudil as the prodrugs of hydroxyfasudil were designed and synthesised. Meanwhile, the stability of these three compounds was also investigated. Furthermore, the reason and mechanism of hydrolysis of these compounds were discussed. This work could provide a useful guide for future research.
To guarantee the safety of drinking water quality after chlorination, the formation, distribution and factors influencing the concentrations of haloacetic acids (HAAs) in a water distribution system (WDS) were investigated both on a full-scale WDS (FWDS) and pilot-scale WDS (PWDS) within a city in northern China. The results of both investigations showed that trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA) were the dominating types of HAAs. In the FWDS, variations in the HAA content showed negative correlations with total residual chlorine, pH and non-purgeable organic carbon (NPOC) and positive correlations with temperature and UV254. In the PWDS, the concentration of HAAs after rechlorination followed the rule of ‘first rise and then fall’; therefore, locating an appropriate rechlorination point and lowering the single chlorine dosage could be used as effective measures to control the HAA content in WDSs.