Synthesis of chondroitin sulfate CC and DD tetrasaccharides and interactions with 2H6 and LY111

We synthesized the biotinylated chondroitin sulfate tetrasaccharides CS-CC [-3)βGalNAc6S(1–4)βGlcA(1-]₂ and CS-DD [-3)βGalNAc6S(1–4)βGlcA2S(1-]₂ which possess sulfate groups at O-6 of GalNAc and an additional sulfate group at O-2 of GlcA, respectively. We also analyzed interactions among CS-CC and CS-DD and the antibodies 2H6 and LY111, both of which are known to bind with CS-A, while CS-DD was shown for the first time to bind with both antibodies.     

g‐C3N4‐Based Heterostructured Photocatalysts

Photocatalysis is considered as one of the promising routes to solve the energy and environmental crises by utilizing solar energy. Graphitic carbon nitride (g‐C₃N₄) has attracted worldwide attention due to its visible‐light activity, facile synthesis from low‐cost materials, chemical stability, and unique layered structure. However, the pure g‐C₃N₄ photocatalyst still suffers from its low separation efficiency of photogenerated charge carriers, which results in unsatisfactory photocatalytic activity. Recently, g‐C₃N₄‐based heterostructures have become research hotspots for their greatly enhanced charge carrier separation efficiency and photocatalytic performance. According to the different transfer mechanisms of photogenerated charge carriers between g‐C₃N₄ and the coupled components, the g‐C₃N₄‐based heterostructured photocatalysts can be divided into the following categories: g‐C₃N₄‐based conventional type II heterojunction, g‐C₃N₄‐based Z‐scheme heterojunction, g‐C₃N₄‐based p–n heterojunction, g‐C₃N₄/metal heterostructure, and g‐C₃N₄/carbon heterostructure. This review summarizes the recent significant progress on the design of g‐C₃N₄‐based heterostructured photocatalysts and their special separation/transfer mechanisms of photogenerated charge carriers. Moreover, their applications in environmental and energy fields, e.g., water splitting, carbon dioxide reduction, and degradation of pollutants, are also reviewed. Finally, some concluding remarks and perspectives on the challenges and opportunities for exploring advanced g‐C₃N₄‐based heterostructured photocatalysts are presented.     

Growth and biochemical profiling of artificially associated micropropagated oil palm plantlets with Herbaspirillum seropedicae

The challenges of various biotic and abiotic stresses can imperil the growth of micropropagated plantlets either direct or indirectly. Hence, in this study, a mutual relationship was established between diazotrophs and micropropagated plantlets to enhance plant growth and development. Artificial symbiosis was created for different inoculums of Herbaspirillum seropedicae (Z78), namely sonicated cells, broth culture, and pellet cells with micropropagated oil palm plantlets Elaeis guineensis Jacq. Results reveal significant differences on root volume, total protein content, and Brix value for Z78 broth culture treatment compared with plantlets treated with 25% N. High nitrogenase enzyme activities (6.7?×?10^?4?µmol?C₂H₄ g^?1?h^?1) and indole-3-acetic acid production (205.21?µmol (g?FW)^?1) were also detected on roots of plantlets treated with Z78 broth culture. These beneficial traits reviewed that the application of diazotrophs (Z78) in associative manner for micropropagated plantlets hold vast potential for promoting plant growth and plant’s healthiness.     

Computational characterization of substrate and product specificities,and functionality of S‐adenosylmethionine binding pocket in histone lysine methyltransferases from Arabidopsis,rice and maize

Histone lysine methylation by histone lysine methyltransferases (HKMTs) has been implicated in regulation of gene expression. While significant progress has been made to understand the roles and mechanisms of animal HKMT functions, only a few plant HKMTs are functionally characterized. To unravel histone substrate specificity, degree of methylation and catalytic activity, we analyzed Arabidopsis Trithorax‐like protein (ATX), Su (var)3‐9 h omologs protein (SUVH), Su(var)3‐9 related protein (SUVR), ATXR5, ATXR6, and E(Z) HKMTs of Arabidopsis, maize and rice through sequence and structure comparison. We show that ATXs may exhibit methyltransferase specificity toward histone 3 lysine 4 (H3K4) and might catalyse the trimethylation. Our analyses also indicate that most SUVH proteins of Arabidopsis may bind histone H3 lysine 9 (H3K9). We also predict that SUVH7, SUVH8, SUVR1, SUVR3, ZmSET20 and ZmSET22 catalyse monomethylation or dimethylation of H3K9. Except for SDG728, which may trimethylate H3K9, all SUVH paralogs in rice may catalyse monomethylation or dimethylation. ZmSET11, ZmSET31, SDG713, SDG715, and SDG726 proteins are predicted to be catalytically inactive because of an incomplete S‐adenosylmethionine (SAM) binding pocket and a post‐SET domain. E(Z) homologs can trimethylate H3K27 substrate, which is similar to the Enhancer of Zeste homolog 2 of humans. Our comparative sequence analyses reveal that ATXR5 and ATXR6 lack motifs/domains required for protein‐protein interaction and polycomb repressive complex 2 complex formation. We propose that subtle variations of key residues at substrate or SAM binding pocket, around the catalytic pocket, or presence of pre‐SET and post‐SET domains in HKMTs of the aforementioned plant species lead to variations in class‐specific HKMT functions and further determine their substrate specificity, the degree of methylation and catalytic activity.     

棉铃虫雄性定向抑制剂的研究:风洞和田间试验中醇类物质的抑制效应(英文)

本文研究了棉铃虫雄蛾味刷中几种醇类物质对同种雄蛾行为反应的抑制效应。剂量范围从4×10－4到40μg的风洞剂量试验表明,当剂量为0．4μg,Z9－16∶Ald与Z11－16∶Ald两种混合物的比率为5∶95时,雄蛾有最高反应。当Z11－16∶OH加到上述混合物中,5％的醇浓度完全抑制定向行为。百分率进一步增加,不仅抑制定向行为,同时也影响起飞行为。将Z11－16∶OH与其他三种饱和醇14∶OH,16∶OH,18∶OH以及与结构上相似的Z9－16∶OH比较发现,Z11－16∶OH抑制雄蛾定向的行为最有效。田间施用Z11－16∶OH使其卵孵化率从处理前的34％降低到处理后的17％。     

内蒙古贺兰山狂蛛1新种及2新纪录种（蜘蛛目：平腹蛛科）

记述采自我国内蒙古贺兰山的３种狂蛛,其中贺兰狂蛛Ｚｅｌｏｔｅｓｈｅｌａｎｓｈａｎｓｐ．ｎｏｖ．为１新种,波氏狂蛛ＺｅｌｏｔｅｓｐｏｔａｎｉｎｉＳｃｈｅｎｋｅｌ,１９６３和蔡氏狂蛛ＺｅｌｔｏｅｓｔｓａｉｉＰｌａｔｎｉｃｋｅｔＳｏｎｇ,１９８６是内蒙古新纪录。     

Microbial production of a novel trihydroxy unsaturated fatty acid from linoleic acid

A bacterium isolated from a dry soil sample collected from McCalla, AL, USA, converted linoleic acid to a novel compound, 12,13,17-trihydroxy-9 (Z)-octadecenoic acid (THOA). The organism is a Gram-positive, non-motile rod (0.5 μ m × 2 μ m). It was identified as a species of Clavibacter ALA2. The product was purified by high pressure liquid chromatography, and its structure was determined by ¹H and ¹³C nuclear magnetic resonance and Fourier transform infrared spectroscopies, and by mass spectrometer. Maximum production of THOA with 25% conversion of the substrate was reached after 5–6 days of reaction. THOA was not further metabolized by strain ALA2. This is the first report of a 12,13,17-trihydroxy unsaturated fatty acid and its production by microbial transformation. Some dihydroxy intermediates were also detected. THOA has a structure similar to those of known plant self-defense substances. Received 13 January 1997/ Accepted in revised form 05 May 1997     

Female sex pheromone of Sesamia cretica: chemical and behavioural evidence for a three-component blend

The female‐produced sex pheromone of the Durra stem borer, Sesamia cretica (Lederer) (Lepidoptera: Noctuidae), had been previously characterized as a 75:25 blend of (Z)‐9‐tetradecenol (Z9‐14:OH) and (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc) based on field trapping experiments. The low attraction of this blend in the field led us to further investigate the sex pheromone of this pest. Coupled gas chromatography with electroantennographic detection (GC‐EAD) analysis of female pheromone gland extracts consistently revealed three EAD‐active compounds. According to their GC retention times, mass spectra, and comparative EAG analyses with authentic standards, two of these compounds were found to be the previously reported components Z9‐14:OH and Z9‐14:OAc, whereas a third compound was identified as (Z)‐11‐hexadecenol (Z11‐16:OH). In wind tunnel experiments, the highest male responses were elicited by ratios of Z9‐14:OH, Z9‐14:OAc, and Z11‐16:OH, ranging from 90:1:9 to 90:5:5. In field tests, the 90:1:9 ratio of the blend loaded onto rubber septum dispensers was significantly more effective than single‐component, two‐component, and any other ratio of the three‐component blend. The greater effectiveness of this blend resulted in a more accurate detection of S. cretica flight activity compared with the previously reported two‐component blend.     

ATPase Activity in Isolated Flagella from Euglena gracilis

SYNOPSIS. The ATPase activity of isolated flagella was studied in Euglena gracilis strain Z in the presence of Mg⁺⁺ or Ca⁺⁺. With Mg⁺⁺, the optimum activity was at pH 7 and with Ca⁺⁺, at pH 9. The K _m values were respectively 6.6 × 10⁻⁴ and 3.6 × 10⁻⁴. Activity was influenced also by temperature and ionic strength. Results with inhibitors of membrane ATPase suggest the presence of a specific contractile system in the flagella. Our results are compatible with a multicomponent enzymic system containing 2 active ATPases.     

Probing the role of Valine 185 of the D1 protein in the Photosystem II oxygen evolution

In Photosystem II (PSII), the Mn₄CaO₅-cluster of the active site advances through five sequential oxidation states (S₀ to S₄) before water is oxidized and O₂ is generated. The V185 of the D1 protein has been shown to be an important amino acid in PSII function (Dilbeck et al. Biochemistry 52 (2013) 6824–6833). Here, we have studied its role by making a V185T site-directed mutant in the thermophilic cyanobacterium Thermosynechococcus elongatus. The properties of the V185T-PSII have been compared to those of the WT*3-PSII by using EPR spectroscopy, polarography, thermoluminescence and time-resolved UV–visible absorption spectroscopy. It is shown that the V185 and the chloride binding site very likely interact via the H-bond network linking Tyr_Z and the halide. The V185 contributes to the stabilization of S₂ into the low spin (LS), S?=?1/2, configuration. Indeed, in the V185T mutant a high proportion of S₂ exhibits a high spin (HS), S?=?5/2, configuration. By using bromocresol purple as a dye, a proton release was detected in the S₁Tyr_Z?→?S₂^HSTyr_Z transition in the V185T mutant in contrast to the WT*3-PSII in which there is no proton release in this transition. Instead, in WT*3-PSII, a proton release kinetically much faster than the S₂^LSTyr_Z?→?S₃Tyr_Z transition was observed and we propose that it occurs in the S₂^LSTyr_Z?→?S₂^HSTyr_Z intermediate step before the S₂^HSTyr_Z?→?S₃Tyr_Z transition occurs. The dramatic slowdown of the S₃Tyr_Z?→?S₀Tyr_Z transition in the V185T mutant does not originate from a structural modification of the Mn₄CaO₅ cluster since the spin S?=?3?S₃ EPR signal is not modified in the mutant. More probably, it is indicative of the strong implication of V185 in the tuning of an efficient relaxation processes of the H-bond network and/or of the protein.