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Activity enhancement of CotA laccase by hydrophilic engineering, histidine tag optimization and static culture
No full textCotA protein from Bacillus subtilis is of laccase activity. The solubility of recombinant CotA is low, which hinders its application. In this study, histidine tag position optimization and hydrophilic engineering were applied to increase the yield and activity of CotA protein. The results showed that the protein yield of CotA with his tag at C-terminal (CH6-CotA) was four times of that of NH6-CotA (His tag at N-terminal). Then, 23 single mutants were constructed by substitutions of hydrophobic residues with hydrophilic amino acids. Among them, the protein yield of the mutant F207Y was increased by 30%; the catalytic activity (kcat/Km) of V403T and P455S was two and three times higher than that of CH6-CotA, respectively. Finally, triple mutant F2071Y/V403T/P455S with C-terminal his-tag (CH6-TSY) was constructed. When the proteins were expressed in microanaerobic condition, the activities of mutants CH6-P455S and CH6-TSY were enhanced about 48- and 42-folds compared to that of NH6-CotA in non-static culture
Alteration in sperm characteristics, endocrine balance and redox status in rats rendered diabetic by streptozotocin treatment: attenuating role of Loranthus micranthus
No full textObjectives: Loranthus micranthus is widely used in Nigerian folklore treatment of male infertility and diabetes complications. We investigated this claim in rats rendered diabetic by streptozotocin (STZ). Methods: Induction of diabetes mellitus in adult male Wistar rats was by intraperitoneal injection of STZ (60 mg/kg). The diabetic rats were thereafter treated orally once/day with 5 mg/kg Gilbenclamide or L. micranthus (100 mg/kg or 200 mg/kg) and monitored for 14 days. Clinical observations, hormonal profile, oxidative stress parameters, glucose metabolism enzymes, histopathological examination, apoptotic marker immunoreactivity and western blotting in testes and sperm parameters were evaluated to examine effects of L. micranthus on STZ-diabetic rats. Results: L. micranthus treatment significantly reduced the blood glucose level (45.9% and 84.7% on the 7th and 14th post-treatment days, respectively); increased antioxidant status, improved microarchitecture of testes, reduced lipid peroxidation and increased BCI-2 protein expression in diabetic rats relative to control. Furthermore, treatment with L. micranthus increased steroidogenic enzymes activities, levels of steroid hormones and improved sperm quality, relative to control. Conclusion: The anti-diabetic and aphrodisiac properties exhibited by L. micranthus could be contingent on its ability to restore a balance to the compromised redox status that characterizes male reproductive dysfunction in diabetes
Antioxidant and Hepatoprotective Effects of Methanolic Extracts of Zilla spinosa and Hammada elegans Against Carbon Tetrachloride-induced Hepatotoxicity in Rats
No full textThe detoxification, metabolism, and excretion of various endogenous and exogenous materials occur mainly in the liver. Liver diseases are a global concern, and classified as chronic hepatitis, cirrhosis, and hepatosis. The development of safe hepatoprotective agents remains an unmet need. Therefore, we investigated the antioxidant effects of methanolic and n-hexane fractions of Zilla spinosa (ZSM and ZSH, respectively) and Hammada elegans (HEM and HEH, respectively) against carbon tetrachloride (CCl4)-induced liver toxicity in rats. Antioxidant activity was studied by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The rats were divided into 11 groups (n=6)-group 1 (control), group 2 (CCl4 only), group 3 (CCl4 + silymarin 10 mg/kg), group 4 (CCl4 + HEM 250 mg/kg), group 5 (CCl4 + HEM 500 mg/kg), group 6 (CCl4 + HEH 250 mg/kg), group 7 (CCl4 + HEH 500 mg/kg), group 8 (CCl4 + ZSM 250 mg/kg)
A base promoted one pot solvent free version of the Ramachary reductive coupling/alkylation reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates
No full textAn N,N-diisopropylethylamine promoted solvent-free Ramachary reductive coupling/alkylation (RRC/A) reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates has been developed. A series of 2,2-disubstituted ethyl cyanoacetates were synthesized in one pot by the RRC/A reaction of commercially available aldehydes, ethyl cyanacetates, alkyl halides and Hantzsch ester. A solvent free two step multicomponent reaction has also been developed for the preparation of 2,2-dialkylated malononitriles and 2,2-dialkylated 4-nitrophenyl acetonitriles. All the designed RRC/A products could be easily obtained with good yields by these methods
The distributional list of amphibians and reptiles in Sichuan Province,China
No full text四川省两栖爬行动物分布名录在《四川两栖类原色图鉴》和《四川爬行类原色图鉴》的基础上,参照《中国两栖动物及其分布彩色图鉴》(2012)和《中国爬行纲动物分类厘定》(2015)的分类体系,对四川省的两栖爬行动物种类和分布进行了核实和厘定。统计显示,目前四川省分布的两栖动物有2目12科37属107种,其中特有种80种,外来种1种;爬行动物有2目15科47属107种,其中特有种42种,外来种1种。本名录的发布,能在一定程度方便相关人员更好地了解四川省两栖爬行动物种类变动和分布,为四川省两栖爬行动物资源保护提供依据
Salinity Adaptation in Ions Adjustments of the Red-eared Slider Turtle Using Liver Transcriptomic Data
No full text外来有害入侵物种红耳龟(Trachemys scripta elegans),原属于淡水龟类,但目前研究发现其可存活于半咸水环境中,这使得未来红耳龟可入侵的潜在范围及危害将增大。为了探究红耳龟对盐度适应的分子机制,本研究应用高通量转录组测序技术,分析其在不同盐度环境中参与离子调节的主要基因及通路。我们设计了三个处理组:对照组(自来水)、低盐度组(0.5%,即盐度5组)和高盐度组(1.5%,即盐度15组),慢性胁迫8周后,分析血液中无机离子、葡萄糖及皮质醇含量,并对其肝脏转录组数据进行分析。结果表明,与对照组相比,盐度5组血液渗透压、[Na+]和血糖差异不显著(p>0.05),而盐度15组显著升高;血液[Cl-]三组间差异均显著;两个盐度处理组血液[K+]显著低于对照组(p<0.05);但血液皮质醇含量在三组之间差异均不显著。 GO (Gene ontology)富集分析发现,参与离子调节的基因主要有电压门控钾通道亚家族5 (KCNH5)、电压门控钠通道I (SCN1B)、利尿肽前体A (NPPA)、ATP酶(ATPeFOA, MTATP6, ATP6)、葡萄糖激酶(GCK)、盐诱导激酶(SIK)、脂联素(ACDC)和类固醇17alpha-单氧酶(CYP17A)等。所筛选出的基因大多被富集到与能量代谢、脂肪代谢、碳水化合物代谢以及内分泌系统等KEGG通路类别中。综上所述,红耳龟在盐度适应过程中参与离子调节的大部分KEGG通路以及相关的生理指标均未发生显著变化,说明它能较好地适应慢性低盐度胁迫(盐度0.5%左右)
Recent advances in poly-gamma-glutamic acid production by microbial fermentation
No full text天然存在的高分子生物聚合物gamma-聚谷氨酸(gamma-PGA)因具生物可降解性、无毒性和非免疫原性而被广泛应用于食品、工业和医疗等领域,主要由微生物发酵制备;当前gamma-聚谷氨酸的微生物发酵制备技术在我国基本上处于实验室研究阶段,距离大规模的工业化生产还有很大差距.综述gamma-聚谷氨酸的高产菌株选育,包括分离筛选新的gamma-PGA生产菌株以及对原有的菌株进行遗传诱变和基因操作、合成机制;发酵条件优化,包括对培养基的组成成分(碳源、氮源和金属离子等)和发酵因素(温度、pH和溶氧等)进行优化;发酵方式选择,包括常规的液体发酵方式以及以工农业废弃物为原料的固体发酵方式;分离方法的建立,包括有机溶剂沉淀法和金属离子沉淀法的比较等.最后对gamma-PGA相对分子质量的调控、生产成本、分离纯化、具体合成机制和大规模生产进行展望,以期为gamma-聚谷氨酸工业化生产及在我国进一步的推广应用提供理论支撑
Effects of different sizes of simulated gaps on the soil water-holding capacity of a Picea asperata plantation
No full text选择川西亚高山云杉人工林,模拟自然林窗形成,布置扩展面积分别为小(74 m~2)、中(109 m~2)、大(196 m~2)3个等级的林窗,探索不同疏伐强度对土壤结构及持水性能的影响,并结合细根生物量、土壤有机质含量等参数,试图揭示导致林窗式疏伐后土壤结构及持水性能差异的因素.结果表明,疏伐初期(1年),林窗的形成对表层(0-10 cm)土壤的孔隙状况及持水性能没有显著影响;随着时间的演替,各处理土壤结构及持水性能均得到不同程度的改善.疏伐后8年,小林窗、中林窗和大林窗表层土壤的容重较对照分别低17.91%、7.33%和9.24%,其总孔隙度较对照分别高7.16%、2.81%和3.65%,其非毛管孔隙度较对照分别高32.89%、8.16%和15.79%,但不同强度疏伐对土壤持水性能的影响不显著.细根生物量、土壤有机质含量和水占孔隙比是影响土壤物理结构及持水性能的主要因素.上述结果表明随着林窗式疏伐抚育进程的推进,小林窗能显著改善表层土壤结构,但对土壤持水性能方面的影响不显著
The Morphology of Cloacae in Female Yaoshan Stout Newt, Pachytriton inexpectatus
No full text本文对雌性瑶山肥螈(Pachytriton inexpectatus)的泄殖腔进行了组织学研究,其具有和其他有尾两栖类相似的皮肤形态.虽然不同部位皮肤组织的厚度存在一定差异,但都具有表皮和真皮等相同的基本结构.雌性瑶山肥螈的泄殖腔还具有与精子储藏相关的特殊腺体储精管腺和腹腺,及与腺体结构相关的泄殖腔管.这表明该物种雌性个体的泄殖腔具备了精子储藏功能的形态结构,为其进行多次交配、分批产卵提供了基础
Innovation Trend of International Agricultural S&T and Supply-side Structural Reforms of Agriculture in Southwest Mountainous Area of China
No full text农业科技创新是制约农业发展的主要因素。目前,我国农业的发展正处于变革的重要时期,面对我国农业内部深层次的结构性矛盾,如何加快传统农业的改造、推进农业科技化和现代化建设,是实现我国农业转型发展的关键所在。本文总结了发达国家在农业整体战略布局、人才队伍建设、农业科研机构的职能布局及农业科技创新主体等方面的优化措施,结合我国多山特点,提出山地农业科技化发展的重点方向:以生产、生态、服务及产业化带动能力方面为方向,促进山地农业供给侧结构性改革;同时,结合地方特点,构建现代山地特色农业体系