旱坡地间作群体对作物根际微生物数量的影响

研究了由玉米、草带、辣椒构成的不同间作群体对云南山区旱坡地土壤微生物数量的影响,结果表明:间作玉米和间作辣椒的草带根际微生物数量均高于其它间作和单作处理,其草带的根际细菌、真菌、放线菌和自生固氮菌数量平均值分别是玉米顺坡单作和辣椒单作的4.49倍和22.00倍,3.91倍和6.10倍,6.15倍和26.29倍,4.75倍和5.72倍;间作草带的玉米和辣椒其各类根际微生物数量均高于玉米和辣椒单作;玉米间作辣椒行比为4∶4和6∶6模式的根际土壤微生物数量多于2∶2模式。总的来说,玉米间作辣椒、玉米间作草带和辣椒间作草带的根际土壤微生物数量均多于各作物单作,为进一步改善旱坡地土壤根际微生物环境和明确间作群体根际土壤微生物效应提供了依据。     

Behavioral and cardiopulmonary effects of dexmedetomidine–midazolam and dexmedetomidine–midazolam–butorphanol in the silver fox (Vulpes vulpes)

Objective

To evaluate the behavior and some cardiopulmonary variables of dexmedetomidine–midazolam or dexmedetomidine–midazolam-butor-phanol in the silver fox (Vulpes vulpes).

Reduction of soil heavy metal bioavailability by nanoparticles and cellulosic wastes improved the biomass of tree seedlings

The purpose of this study was to use zero‐valent iron nanoparticles (nZVI) and cellulosic wastes to reduce bioavailability of lead (Pb) and cadmium (Cd), and to establish Persian maple seedlings (Acer velutinum Bioss.) in contaminated soil. One‐year‐old seedlings were planted in pots filled with unpolluted soil. Lead [Pb(NO₃)₂] and Cd [Cd(NO₃)₂] were added with concentrations of 0 (Control), 100 (Pb100), 200 (Pb200), and 300 (Pb300) mg kg⁻¹ and 10 (Cd10), 20 (Cd20), and 30 (Cd30) mg kg⁻¹. Cellulosic wastes were mixed with soil at the same time of planting [four levels: 0, 10 (W1), 20 (W2), 30 (W3) g 100 g⁻¹ soil]. The nZVI was prepared by reducing Fe³⁺ to Fe⁰ and injected to pots [four levels: 0, 1 (N1), 2 (N2), and 3 (N3) mg kg⁻¹]. Height, diameter, biomass, tolerance index of seedlings, bioavailability of heavy metals in soil, and removal efficiency of amendments were measured. The highest values of seedling characteristics were observed in N3. The highest removal efficiency of Pb (Pb100: 81.95%, Pb200: 75.5%, Pb300: 69.9%) and Cd (Cd10: 92%, Cd20: 73.7%, Cd30: 68.5%) was also observed in N3. The use of nZVI and cellulosic waste could be a proper approach for seedling establishment in forests contaminated with heavy metals.     

Soil Carbon Dynamics Under Changing Climate——A Research Transition from Absolute to Relative Roles of Inorganic Nitrogen Pools and Associated Microbial Processes: A Review

It is globally accepted that soil carbon (C) dynamics are at the core of interlinked environmental problems,deteriorating soil quality and changing climate.Its management remains a complex enigma for the scientific community due to its intricate relationship with soil nitrogen (N) availability and moisture-temperature interactions.This article reviews the management aspects of soil C dynamics in light of recent advances,particularly in relation to the availability of inorganic N pools and associated microbial processes under changing climate.Globally,drastic alterations in soil C dynamics under changing land use and management practices have been primarily attributed to the variation in soil N availability,resulting in a higher decomposition rate and a considerable decline in soil organic C (SOC) levels due to increased soil CO2 emissions,degraded soil quality,and increased atmospheric CO2 concentrations,leading to climate warming.Predicted climate warming is proposed to enhance SOC decomposition,which may further increase soil N availability,leading to higher soil CO2 efflux.However,a literature survey revealed that soil may also act as a potential C sink,if we could manage soil inorganic N pools and link microbial processes properly.Studies also indicated that the relative,rather than the absolute,availability of inorganic N pools might be of key importance under changing climate,as these N pools are variably affected by moisture-temperature interactions,and they have variable impacts on SOC turnover.Therefore,multi-factorial studies are required to understand how the relative availability of inorganic N pools and associated microbial processes may determine SOC dynamics for improved soil C management.     

海藻酸钙固定木霉分生孢子高效降解敌敌畏研究

成功建立了高效降解敌敌畏的海藻酸钙交联固定木霉AMT-28分生孢子体系.与固定化的菌丝或自由悬浮的菌丝相比,固定不同浓度分生孢子小球的敌敌畏降解能力均有显著提高,其中以每100 mL海藻酸钠-硅藻土悬液固定107个分生孢子小球的效果最佳.同时,孢子固定化小球在敌敌畏降解过程中保持了较高的储存稳定性和良好的重复使用性能.因此,此项技术必将在敌敌畏水污染处理方面得到广泛的应用.     

电化学酶传感器在有机磷农药残留检测中的应用

从识别有机磷农药的酶及识别机理、酶的固定化技术、酶固定化载体等不同角度,综述了有机磷农药电化学酶传感器的研究概况,并展望了其发展前景。     

家蚕核型多角体病毒ODV囊膜蛋白基因的融合表达及引导外源蛋白进入多角体的研究

为了探索家蚕核型多角体病毒(BmNPV)的包涵体衍生病毒(ODV)囊膜蛋白在病毒粒子包涵入多角体过程中的作用,选择2个ODV囊膜蛋白ODV-E25和ODV-E56作为研究对象,利用能够表达多角体蛋白的BmNPV Polh+Bac-to-Bac表达系统构建了融合表达E25-EGFP和E56-EGFP的重组病毒,在家蚕卵巢培养细胞系(BmN)中进行表达和定位分析。结果表明2种融合蛋白均在BmN细胞中成功表达,并于荧光显微镜下观察到绿色荧光主要分布在细胞核中。从感染的BmN细胞中收集纯化多角体,观察到多角体也能激发出绿色荧光,用Western blot方法进一步证实多角体中含有融合蛋白。这一现象表明当囊膜蛋白基因与外源基因融合表达时,外源融合蛋白能够进入多角体内部,推测这2种ODV囊膜蛋白不仅在病毒粒子包涵入多角体的过程中起信号引导作用,并能引导外源目的蛋白进入多角体。     

嫁接对茄子根际土壤微生物和叶片硝酸还原酶的影响

以野生茄‘托鲁巴姆’ (Solanum torvum ) 为砧木, 茄子(S. m elongena) ‘西安绿茄’品种为接穗, 研究了嫁接茄根际土壤微生物生理类群和土壤水解酶活性及叶片硝酸还原酶活性的动态变化特点,分析了嫁接茄根际土壤微生物生理类群和土壤水解酶与叶片硝酸还原酶活性的关系, 探讨了嫁接提高茄子氮素转化和吸收与土壤生物活性的关系。结果表明: 嫁接茄根际土壤微生物生理类群和土壤水解酶活性均较自根茄有增加的趋势。但不同发育时期也有一定的变化。嫁接茄叶片硝酸还原酶活性随着生育均表现出逐渐增加的趋势, 且显著高于自根处理。嫁接茄的固氮菌、硝化细菌和脲酶与其叶片硝酸还原酶活性均呈显著或极显著正相关。总体上看, 嫁接显著增加了茄子根际土壤固氮菌、硝化细菌和脲酶活性, 嫁接茄株也表现出较高的硝酸还原酶活性。     

底物添加对森林2个不同演替阶段土壤氨基糖动态的影响

以鼎湖山马尾松林和季风林2个演替阶段的土壤为研究对象,采用室内恒温(25 ℃)培养,研究了葡萄糖和不同数量无机氮施入对土壤氨基糖(氨基葡萄糖、氨基半乳糖和胞壁酸)动态的影响,并利用氨基葡萄糖和胞壁酸的比值探讨了真菌和细菌残留物在碳氮固持过程中的相对贡献。结果表明:在整个培养期间,季风林土壤氨基糖总量显著高于马尾松林,尤其在培养初期,增幅远高于马尾松林, 在培养后期,马尾松林土壤氨基糖含量下降幅度高于季风林。底物添加对不同微生物来源的氨基糖单体含量的影响也有所差异,以胞壁酸为代表的细菌细胞壁残留物比真菌更易受到外源物质的影响,但真菌细胞壁残留物对土壤有机质的截获和稳定作用大于细菌。真菌、细菌残留物的积累和转化过程可以通过氨基葡萄糖和胞壁酸的比值反映,细菌在培养前期更容易利用外源物质,但随着培养时间的进行,真菌占据了主导地位。不同碳氮比的外源底物对氨基糖总量和各氨基糖单体含量的动态影响不显著。与马尾松林相比,处在演替顶级的季风林土壤易于利用活性底物,显著促进了碳氮的微生物固持和微生物残留物在土壤中的保留,这说明土壤氨基糖作为微生物残留物可以探讨土壤碳氮的耦合机制,对调节土壤碳氮的养分平衡具有重要意义。      

基于响应面法的海藻酸钠固定β-呋喃果糖苷酶工艺优化

糖苷酶在水解/合成生产功能性食品配料(含低聚糖)方面扮演着重要角色。为提高糖苷酶的重复利用率与稳定性,本文对影响海藻酸钠固定化β-呋喃果糖苷酶(β-fructofuranosidase,FFase)工艺的因素进行分析,利用响应面法对固定化酶工艺进行优化,最后对所得固定化酶的稳定性进行评价。结果表明:影响海藻酸钠固定化FFase工艺的关键因素及最佳条件为4 g/L海藻酸钠、固定42 min、交联温度26℃,酶活回收率为60.95%;在此条件下与游离酶相比,4℃下保存12 d后,酶活力依然有60%以上,具有良好的储存稳定性;在温度低于70℃范围内有良好的热稳定性。连续使用5次后,其固定酶活仍保持初始酶活的51.71%,具有良好的重复再利用性。