Highly active Cu/SiO_2 catalysts for hydrogenation of diethyl malonate to 1,3-propanediol

Cu/SiO2 catalysts prepared by the ammonia evaporation method were applied to hydrogenation of diethyl malonate to 1,3‐propanediol. The calcination temperature played an important role in the structural evolution and catalytic performance of the Cu/SiO2 catalysts, which were systematically characterized by N2 adsorption‐desorption, inductively coupled plasma‐atomic emission spectros‐copy, N2O chemisorption, X‐ray diffraction, Fourier transform infrared spectroscopy, H2 tempera‐ture‐programmed reduction, transmission electron microscopy, and X‐ray photoelectron spectros‐copy. When the Cu/SiO2 catalyst was calcined at 723 K, 90.7%conversion of diethyl malonate and 32.3%selectivity of 1,3‐propanediol were achieved. Compared with Cu/SiO2 catalysts calcined at other temperatures, the enhanced catalytic performance of the Cu/SiO2 catalyst calcined at 723 K can be attributed to better dispersion of copper species, larger cupreous surface area and greater amount of copper phyllosilicate, which results in a higher ratio of Cu＋/Cu0. The synergetic effect of Cu0 and Cu＋is suggested to be responsible for the optimum activity.

Effects of Adaptation to Elevated Salinity on Some Enzymes' Salt_tolerance in Vitro and Physiological Changes of Eelgrass

The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determined under a salinity grade in vitro So were the photosynthesis rates of the plants from the three treatments in the media with different salinities 100%, 150%, 200%, 300% ASW) and Some physiological data. The data showed that under increased salinities (concentrated seawater), Na+, Cl-, MDA (malon dialdehyde) and glucose contents and the osmotic potentials ( absolute value) in the leaves increased with the salinity elevation in the medium (ASW), but both K+ and free amino acid (mainly proline) contents decreased. Malate dehydrogenase (MDH) from the plant leaves under a salinity grade showed its activities (A) as follows: A(100%) (ASW) > A(150%) (ASW) > A(200%) (ASW). Phosphoenolpyruvate carboxylase (PEPC) extracted from the 100% ASW- and 200% ASW-treated plants showed similar activities (both insensitive to salinities) under the salinity grade in vitro, but the activities of PEPC from plants treated with 150% ASW were dependent oil salinity. Whether the plant is stressed at 150% ASW and can stand higher salinity than seawater needs to be studied further. Meantime, die data do not agree with the opinion that the adaptation of the eelgrass to seawater salinity is partly fulfilled by its insensitiveness to salinities in Some metabolic enzymes. It can be inferred that the lack of transpiration may be an important aspect of tire plant's tolerance to seawater salinity.

简论“微生物遗传学”课程

微生物遗传学是以微生物作为对象,研究遗传和变异的科学,是遗传学的分支学科。微生物的种类繁多,无论在外部形态,内部结构。

Effects of Used Battery on Key Enzyme Activity during the Germination of Wheat Seeds

[Objective] This study aimed to explore the effects of used battery lixivium on wheat germination. [Method] The wheat seeds were treated with used battery lix- ivium at different concentrations to detect the change of activities of amylase, pro- tease, pyruvate dehydrogenase （PDH） and polyphenol oxidase （PPO） during the ger- mination period. [Result] The results showed that the used battery affected enzyme activity. With the increase of concentration of used battery lixivium, trends of the changes of amylase and protease activities were not different. The activities were en- hanced at low concentrations of lixivium, while were inhibited at high concentrations. The tends of changes of pyruvate dehydrogenase （PDH） and polyphenol oxidase （PPO） activities were not consistent with that of either amylase or protease, which showed continuous downward trends with the increasing concentration of used battery lixivium. [Conclusion] This study is of great practical significance for understanding the effects of used battery lixivium on the germination of wheat seeds.

Promotive Effects of Alginate-Derived Oligosaccharides on the Inducing Drought Resistance of Tomato

In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Ly-copersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6 molL-1 PEG-6000 solution for 6 h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

Effective production of γ-valerolactone from biomass-derived methyl levulinate over CuO_x-CaCO_3 catalyst

The production of?-valerolactone(GVL)from lignocellulosic biomass has become a focus of research owing to its potential applications in fuels and chemicals.In this study,(n)CuOx-CaCO3(where n is the molar ratio of Cu to Ca)compounds were prepared for the first time and shown to function as efficient bifunctional catalysts for the conversion of biomass-derived methyl levulinate(ML)into GVL,using methanol as the in-situ hydrogen source.Among the catalysts with varied Cu/Ca molar ratios,(3/2)CuOx-CaCO3 provided the highest GVL yield of 95.6% from ML.The incorporation of CaCO3 with CuO resulted in the formation of Cu+species in a CuOx-CaCO3 catalyst,which greatly facilitated the hydrogenation of ML.Notably,CuOx-CaCO3 also displayed excellent catalytic performance in the methanolysis products of cellulose,even in the presence of humins.Therefore,a facile two-step strategy for the production of GVL from cellulose could be developed over this robust and inexpensive catalyst,through the integration of cellulose methanolysis catalyzed by sulfuric acid,methanol reforming,and ML hydrogenation in methanol medium.

Ordered macroporous boron phosphate crystals as metal-free catalysts for the oxidative dehydrogenation of propane

Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity.In this study,boron phosphate crystals with a three-dimensionally interconnected ordered macroporous structure and a robust framework were fabricated and used as stable and selective catalysts in the oxidative dehydrogenation(ODH)of propane.Due to the improved mass diffusion and higher number of exposed active sites in the ordered macroporous structure,the catalyst exhibited a remarkable olefin productivity of^16 golefin gcat^-1 h^-1,which is up to 2–100 times higher than that of ODH catalysts reported to date.The selectivity for olefins was 91.5%(propene:82.5%,ethene:9.0%)at 515℃,with a propane conversion of 14.3%.At the same time,the selectivity for the unwanted deep-oxidized CO2 product remained less than 1.0%.The tri-coordinated surface boron species were identified as the active catalytic sites for the ODH of propane.This study provides a route for preparing a new type of metal-free catalyst with stable structure against oxidation and remarkable catalytic activity,which may represent a potential candidate to promote the industrialization of the ODH process.

Gold-iridium catalysts for the hydrogenation of biomass derived products

Au-Ir and Au-Ru on TiOz catalysts prepared by sequential deposition-precipitation technique were compared with the corresponding monometallics in the hydrogenation of levulinic acid to y-valero]actone. Interestingly the addition of Ao to Ir/TiO2 showed a detrimental effect on the activity of Ir monometallic catalyst whereas a positive synergistic effect was shown in the case of Ru. Both catalysts were reduced under H2 to increase the M0-Au0 interaction, From previous DFT calculations and catalytic test, we addressed the lower activity of Au-lr/TiO2 than that of Ir/TiO2 to the interference of Au into the redox mechanism of lr atoms.

Solubilities of 1-Methyl-3-（3-sulfopropyl）-imidazolium Hydrogen Sulfate in Selected Solvents

Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC) . The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were meas-ured using a static analytical method and correlated with an empirical equation.

Tuning catalytic selectivity of propane oxidative dehydrogenation via surface polymeric phosphate modification on nickel oxide nanoparticles

Thermal stability has long been recognized as a major limitation for the application of ligand modification in high-temperature reactions. Herein, we demonstrate polymeric phosphate as an efficient and stable ligand to tune the selectivity of propane oxidative dehydrogenation. Beneficial from the weakened affinity of propene, NiO modified with polymeric phosphate shows a selectivity 2–3 times higher than NiO towards the production of propene. The success of this regulation verifies the feasibility of ligand modification in high-temperature gas-phase reactions and shines a light on its applications in other important industrial reactions.

Deuterium Isotope Effects in Oxidative Deamination of L-Alanine Catalyzed by L-Alanine Dehydrogenase

Solvent and kinetic isotope effects in the reaction of oxidative deamination of L-alanine, catalyzed by L-alanine dehydrogenase, AIaDH, （EC 1.4.1.1） were determined using a non-competitive spectroscopic method. The progress of the reaction was monitored spectrophotometrically by measuring the increasing absorbance of the reduced form of NADH at 340 nm. L-alanine, stereospecifically labeled with deuterium was synthesized by enzymatic reductive amination of pyruvate in presence of [（4R）-2H]-NADH, which was obtained by deuterium transfer from deuteriated formic acid to NAD~ catalyzed by FDH （formate dehydrogenase） （EC 1.2.1.2）. [2-2H]-L-alanine, the product of enzymatic synthesis catalyzed by AIaDH, was obtained with 75% deuterium enrichment and values of isotopic effects were approximated to the values corresponding to 100% of deuterium incorporation. The enzyme AIaDH isolated from Bacillus subtilis shows pro-R stereospecificity, what indicates that hydrogen is exclusively transferred from pro-R position at C-4 of the nicotinamide ring of NADH to C-2 of pyruvate to form L-alanine. Some intrinsic mechanistic details of enzymatic oxidative deamination of L-alanine were discussed using determined numerical values of kinetic and solvent isotope effects on Vmax and Vmax,│KM

Mitochondrial pyruvate dehydrogenase E1 of Nosema bombycis:A marker in Microsporidian evolution

Microsporidia are a group of intracelluar eukaryotic parasites, which can infected almost all animals, including human beings. Till now, no mitochodria but mitosome, a remnant of mitochondria was discovered in this phylum. We present here the mitochondrial pyruvate dehydrogenase El （PDH, including PDHα and PDHβ） of the microsporidian Nosema bombycis, the pathogen of silkworm pebrine. Compared with PDH of microsporidian Encephalitozoon cuniculi and Antonospora locustae, both subunits are eonscrced. The phylogeny indicated that both subunits are mitochondrial. The syntenic maps revealed the subunits organization of NbPDH is distributed in different scaffolds, similar to that of EcPDH but different with AIPDH, and the relationship between phylogeny tree and organization of PDH suggest that the AlPDH subunits organization is the ancestral style of microsporidia, and through the genome evolution, the reshuffling of the chromosome of microsporidia occurred, the adjacent style of ALPDHE1 organization changed, and the two subunits separated and located to different chromosomes in E. cuniculi. For N. bombycis and N. ceranae, they locate to different scaffolds. In order to determine NbPDH subcellular localizations, we prepared the polyclonal antibodies against NbPDH prokaryotic fusion proteins, and adopted the colloidal gold immunological electron microscopy, the expression signals of NbPDH were observed in spores however, the subcellular localization were not definited. In general, through comparison of three mierosporidian PDH molecular phylogeny, subunits organization in chromosomes, localization indicated that PDH is an interesting marker in microsporidia evolution

Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

In this work,a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder.The morphology and structure of the acidic montmorillonite/cordierite samples were characterized by means of X-ray diffraction(XRD),N_2 adsorption/desorption isotherms,and scanning electron microscope(SEM).The cleavage of cumene hydroperoxide(CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts.The influences of acidic montmorillonite loading,reaction temperature.CHP concentration,and weight hourly space velocity(WHSV) on the catalytic activity and selectivity of phenol were studied.The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact,and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations.The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite.Under the optimal reaction conditions(acidic montmorillonite loading of 32.5%(by mass),temperature of 80 ℃,a mass ratio of CHP to acetone of 1:3,and WHSV of CHP of 90 h^(-1)),the conversion of CHP can reach 100%,and the selectivity of phenol is up to 99.8%.

Synthesis of Some New Nitrogen Bridge-Head Pyrido [1,2,4]Triazepines

Ring closure reactions of 1, 6-diamino-4- （4-chlorophenyl）-2-oxopyridine-3, 5-dicarbonitrile （1） with various 1, 3-dielectrophiles namely, diethyl malonate, ethyl cthoxymethylene cyanoacetate, 2-cyano-3, 3-bis（methylthio） acrylonitril, dimethyl acetylenedicarboxylate, dehydroacetic acid, chromon- 3-carbonitrile and 3-formylchromone led to the formation of the target bihetherocylicl,2,4-triazepines. The effect of 3-phenylazo-2, 4-pentandione, ethyl ct-cyano-ct-phenylazoacetate and 3, 1-benzoxazin-4-one derivative on 1 was also discussed.

带脱氧反密码子的酵母丙氨酸tRNA类似物失去了它的掺入活力

在另一篇文章中,我们已经证明酵母丙氨酸tRNA接受茎中某些2′-羟基对于该tRNA与氨酰tRNA合成酶的识别是重要的。本文希望探讨酵母丙氨酸tRNA反密码子中的核糖的功能。我们以前的研究证明,酵母丙氨酸tRNA反密码环并不参与tRNA与合成酶的相互作用。因此可以用脱氧核糖核苷酸取代tRNA的反密码子而不用担心接受活力的丧失。我们的研究也证明了具有GGC(天然的为IGC)

Effects of dichloroacetate on the activation of the mitochondrial pathway in C6 cells in vitro

Mitochondria are increasingly recognized as important targets for tumor treatment because of their central roles in apoptotic pathways and cellular metabolism. Dichloroacetate （DCA）, a low molecular weight mitochondria-targeting agent, exhibits potential therapeutic effects for tumors. Based on the effects of DCA on tumor cellular metabolism, we carried out this study to investigate the anti-tumor activity of DCA in C6 glioma cells in vitro. The results showed that DCA was able to increase the activity of pyruvate dehydrogenase （PDH）, induce the production of reactive oxygen species （ROS） and reduce the mitochondrial membrane potential （MMP） in C6 ceils in vitro （P〈0.05 or 0.01）, indicating that the anti-tumor effects of DCA in C6 cells could be through the activation of the mitochondrial pathway. In conclusion, mitochondria could be a viable therapeutic target for the treatment of glioma.

An emerging hemorrhagic fever in China caused by a novel bunyavirus SFTSV

Severe fever with thrombocytopenia syndrome(SFTS) is an emerging hemorrhagic fever in rural areas of China and is caused by a new bunyavirus,SFTSV,named after the disease.The transmission vectors and animal hosts of SFTSV are unclear.Ticks are the most likely transmission vectors and domestic animals,including goats,dogs,and cattle,are potential amplifying hosts of SFTSV.The clinical symptoms of SFTS are nonspecific,but major symptoms include fever,gastrointestinal symptoms,myalgia,dizziness,joint pain,chills,and regional lymphadenopathy.The most common abnormalities in laboratory test results are thrombocytopenia(95%),leukocytopenia(86%),and elevated levels of serum alanine aminotransferase,aspartate aminotransferase,creatine kinase,and lactate dehydrogenase.The fatality rate for SFTS is 12% on average,and the annual incidence of the disease is approximately five per 100000 of the rural population.