黄孢原毛平革菌对固体介质中染料的降解反应

用黄孢原毛平革菌(Phanerochaetechrysosporium)3品系在固体介质中建立染料的降解反应体系,分光光度法测定染料的脱色降解率。黄孢原毛平革菌在琼脂、沙子及土壤等固体介质中均能有效地降解偶氮染料、蒽醌染料及聚合染料;植物材料玉米芯和木屑可作为共代谢碳源被该菌利用;BKM F 1767菌种降解能力最强,对活性艳蓝KN R的进攻性优于对PolyR 478和比布列希猩红。     

白腐真菌降解五氯酚的初步研究

研究了白腐真菌黄孢原毛平革菌在不同营养条件下对五氯酚的降解.采用土豆葡萄糖液体培养基,接种后第2天投加PCP,在胞外木质素降解酶活性极低的真菌反应体系中,五氯酚能够有效降解,4d内10mg·1-1五氯酚降解率达到98%;采用高氮培养基,接种后第6天投加五氯酚,在胞外木质素酶含量极低的真菌反应体系和不含胞外酶的菌丝体反应体系中,五氯酚均能有效降解,1d内降解率分别达到56%和22%;采用低氮培养基,接种后第6天投加五氯酚,在胞外木质素酶含量较高的真菌反应体系、胞外酶液反应体系和不含胞外酶的菌丝体反应体系中,五氯酚均能有效降解,1d内降解率分别达到86%,17%和46%.结果表明,黄孢原毛平革菌在非木质素降解条件下,依赖胞内酶能有效地降解PCP;在木质素降解条件下依赖胞外木质素降解酶和胞内酶降解五氯酚,降解效率高于非木质素降解条件.     

嗜热子囊菌光孢变种β-葡萄糖苷酶的基因克隆、表达及酶学性质分析

从嗜热子囊菌光孢变种(Thermoascus aurantiacus var.levisporus)RNA中通过RT-PCR克隆出β-葡萄糖苷酶基因bgl Ⅰ的全长序列,cDNA序列为2 672 bp.Genbank登录号为EU269025,将该片段插入巴斯德毕赤酵母Pichia pastoris分泌型表达载体pPIC9K中,获得重组质粒pPIC9K/bgl,经线性化后用电穿孔法导入毕赤酵母GS115中,在醇氧化酶AOXI基因启动子作用下,获得高效表达β-葡萄糖苷酶的毕赤酵母工程菌株.经DEAE-Sepharose Fast Flow阴离子层析纯化了该重组表达蛋白.SDS-PAGER测得该重组蛋白相对分子质量(M)约为120×103.经甲醇诱导,培养基中β-葡萄糖苷酶的活力可达1.2 U/mg,小规模发酵量达0.45 mg/mL.该酶的最适反应温度为60℃,最适反应pH为5.0.于70℃保温30 min仍保持80%的酶活力,具有较高的热稳定性,在pH 3.0～9.0的条件下酸碱耐受性强.图6表1参22     

酵母双杂交筛选OIPK相互作用蛋白

前期研究发现烟草中一个壳寡糖诱导的Ser/Thr蛋白激酶(Oligochitosan induced protein kinase,OIPK)在壳寡糖诱导的烟草抗性反应中起着重要作用.目前在烟草中发现OIPK基因的两个选择性剪接体:OIPKL和OIPKS,其中OIPKL是3个选择性剪接体中序列最长的.为进一步研究OIPK在壳寡糖诱导植物抗性中起的作用,本研究采用酵母双杂交方法,以pGBKT7-OIPKL为诱饵质粒,筛选构建在pACT2载体上的烟草cDNA文库,寻找OIPKL的相互作用蛋白.结果表明OIPKL蛋白在酵母中可以和烟草的S-腺苷甲硫氨酸合成酶、泛素激活酶E1、丙酮酸激酶、过氧化物酶相互作用.实验结果为研究壳寡糖诱导抗性机理提供了一定依据.图3参26     

水稻RBX1基因cDNA的分离及其过量表达载体对水稻的转化

RBX1蛋白是基于Cullin蛋白的E3复合体中的一个亚基,对于基于Cullin蛋白的E3复合体结合E2及Cullin蛋白的活化具有重要作用.利用RT-PCR分离到水稻RBX1cDNA,序列比对分析显示,水稻RBX1与拟南芥、人、果蝇及酵母中该同源蛋白的氨基酸序列一致性分别为80%、74.4%、72%和51.2%.酵母双杂交实验显示,水稻RBX1与水稻Cullin4蛋白有着相互作用.将水稻RBX1cDNA插入植物表达质粒pHB,利用农杆菌介导法将构建好的植物表达载体导入水稻,获得植株38株.以基因组DNA为模板对潮霉素抗性基因片段进行扩增,初步确定其中32株为转基因植株.图5表1参17     

麻疯树叶绿ω3脂肪酸脱饱和酶基因的克隆和鉴定

根据几个已知的植物ω3脂肪酸脱胞和酶基因序列,利用RT-PCR和RACE技术从麻疯树中克隆了一条编码叶绿体ω3脂肪酸脱饱和酶的cDNA序列.对该序列的分析表明,该cDNA的编码区长1 368bp,编码一个长度为455个氨基酸的蛋白质,推测的蛋白质相对分子质量(Mr)大小为52.1×103.同源分析显示,推测的氨基酸序列与其他物叶绿体脂肪酸脱饱和酶具有很高的相似性.RT-PCR分析表明,该基因在麻疯树叶片中有着稳定的表达.此外,还通过酵母表达系统鉴定了该基因编码的酶的功能.对转基因酵母的脂肪酸组成分析发现,α亚麻酸在转基因酵母中积累.上述结果表明,该麻疯树cDNA编码了一个叶绿体ω3脂肪酸脱饱和酶.     

水稻不同亚家族SR蛋白的相互作用

精氨酸和丝氨酸富集蛋白(Arginine/ser ine-rich proteins,SR proteins)是剪切复合体中的重要成员.SR蛋白能够通过C端结构域相互作用并参与前体信使RNA的组成性剪切及可变剪切加工过程.为了揭示水稻SR蛋白间的相互作用网络,利用GAL4酵母双杂交系统,对来自不同亚家族的6个水稻SR蛋白进行相互作用分析.结果发现,来自两个不同亚家族的SR基因SCL30a和SC34共转化酵母能在相应缺陷培养基上生长,α-半乳糖苷酶活性约为对照的17倍,表明两者存在直接的相互作用关系,同时也暗示水稻可能通过SR蛋白直接相互作用,对重要基因的剪切加工及表达进行再次精细调控以应对外界复杂的环境变化.     

黄孢原毛平革菌对氯代蒽的生物降解及降解途径

氯代多环芳烃(chlorinated polycyclic aromatic hydrocarbons, Cl-PAHs)是多环芳烃的氯代衍生物,其毒性与母体相当甚至高于母体,在各种环境介质中广泛存在且难以降解,对生态环境和人类健康具有一定的潜在威胁.微生物降解是环境中去除有机物的主要途径之一,本文以白腐真菌的模式菌种-黄孢原毛平革菌(Phanerochaete chrysosporium, Pc)为代表,优化了Pc菌对氯代蒽的降解条件、探究了降解效果以及降解动力学,并分析了可能的降解途径.结果表明,Pc菌对氯代蒽有一定的降解能力.当液体培养基的初始pH值为4.5,Pc菌接种量约为每毫升1×10~5个时,在35℃,120 r·min~(-1)的恒温摇床中培养6 d后,接入浓度为100 mg·L~(-1)的底物能够达到较高的降解效率.在此条件下降解16 d后9-ClAnt和9,10-Cl_2Ant的降解率分别达到了96.45%和92.83%.动力学分析表明,Pc菌降解氯代蒽的过程符合一级动力学方程.分析降解过程,检测到5种降解中间产物,结合生物催化反应的特点推测了氯代蒽可能的降解途径.     

重金属暴露铜锈环棱螺全组织均一化cDNA文库构建及表达序列标签特征分析

构建cDNA文库是寻找生物新功能基因的有效手段.采用SM ART技术构建了重金属铜和镉暴露铜锈环棱螺全组织均一化cDNA文库,文库库容为1.78×106克隆,重组率大于99%.从初始文库中随机挑取6000个克隆进行测序,获得5 473个高质量表达序列标签(ESTs)序列.经聚类分析得到3 961个Unigene(平均长...     

黄孢原毛平革菌对染料和印染废水的降解

白腐真菌黄孢原毛平革菌在合成木素过氧化物酶的限碳培养条件下，可以降解酶性、直接、活性、阳离子等多种类型的印染工业染料、在培养的d5木素过氧化物酶活力最高时，分别加入酸性染料卡布龙红和弱酸大红，质量浓度（ρ/mgL^-1)分别为25、50、100和12．5、25．50，48h后培养液基本脱色，较高浓度下菌膜上有残余染料吸附，5d后染料质量降解率分别是100％、88％、92％和58％、58％、65％、38％。以含有上述两种染料的印染废水置换培养液，并加入葡萄糖1g/L，黄孢原毛平革菌可以直接使废水脱色，菌丝可以重复培养脱色废水至少5批，每批废水的脱色率均大于90％，5批废水总的染料质量降解率约为80％，在重复培养脱色废水的过程中，测不到木素过氧化物酶的活力，说明废水中的染料分子是在细胞表面或进入胞内被降解的，若加入的葡萄糖浓度降低一半以上，菌丝脱色废水的效果将有所下降，图5表5参11     

HCO3-对铜绿微囊藻、四尾栅藻和小环藻增长特性及竞争行为的影响

HCO3-为湖泊水体中藻类重要的无机碳源,其含量多少的变化对藻类优势种的形成起到重要作用。文章采用含HCO3-培养基HAC与无HCO3-培养基HA对铜绿微囊藻(Microcystis aeruginosa)、四尾栅藻(Scenedesmus Quadricauda)和小环藻(Cyclotellasp.)进行纯培养和共培养竞争实验,考察HCO3-对藻类优势种形成的影响。利用logistic种群增长模型拟合纯培养三藻的生长曲线,并求出最大增长速率r以及Lotka-Volterra竞争模型求出各自竞争参数。铜绿微囊藻与四尾栅藻在HAC中纯培养和共培养的生物量K和最大增长速率r均远大于在HA中,表明这两种藻的增殖需要HCO3-作为碳源平衡胞内营养平衡;小环藻不能在有HCO3-的培养基中生存。在HAC中,铜绿微囊藻与四尾栅藻的平均抑制作用相当,实现共存。铜绿微囊藻在无HCO3-环境中对营养资源更具竞争力,其对四尾栅藻的平均抑制作用是相反抑制的1.6倍,对小环藻的抑制是相反抑制的61倍;四尾栅藻在无HCO3-环境中竞争力弱于铜绿微囊藻强于小环藻,其对小环藻的抑制是相反抑制的10倍;小环藻在HA竞争试验中被淘汰。     

微杆菌3-28对萘、菲、蒽、芘的降解

研究了以多环芳烃为唯一碳源富集培养的微杆菌3-28对不同多环芳烃化合物(Polycyclic aromatichydrocarbons,PAHs)及混合PAHs的降解能力,以及在无机基础培养基中生长时PAHs浓度与一些主要环境因子如pH值、盐度、温度对细菌降解PAHs的影响.结果表明,微杆菌3-28X对萘、菲、蒽和芘均有较高的降解能力,112 h后萘与菲完全降解,而蒽和芘28 d的降解率分别为97.54%、90.2%.初始底物浓度会影响细菌生长速率,底物浓度过高不利于细菌生长.相同培养时间下多底物培养液中的菌群浓度明显高于单底物系统.微杆菌3-28能够在pH 6.0-9.0、盐度10～30g/kg,温度40～55℃的环境下生存,并保持较高的降解能力.图8参33     

灭幼脲（Ⅲ）在甲醇中的光解作用

本文研究了灭幼脲(Ⅲ)在甲醇中的光解作用。以氮气和氧气作饱和气体时,灭幼脲(Ⅲ)在甲醇中的光化学反应均表现为一级动力学形式,其速率常数分别为0.118h~(-1)和0.129h~(-1);当光强为0.50和0.62cal/cm~2·min时,其半衰期分别为5.37和4.42h;灭幼脲(Ⅲ)在甲醇中光解的主要产物包括:邻氯苯甲酰胺,N-苯基氨基甲酸甲酯,N-(对氯苯基)氨基甲酸甲酯以及对氯苯基脲等。本文还对灭幼脲(Ⅲ)在甲醇中的光化学反应机理作了初步探讨。     

基于Web的信息技术考试系统的设计与实现过程

基于Web的考试系统是考试的发展方向，是远程教育的一个重要组成部分．它采用B／S模型．本文分析了基于WEB系统的考试模型及功能，研究了考试系统实现的关键技术，并在具体系统中做了实现．     

Denitrification potential in a Louisiana wetland receiving diverted Mississippi River water

Excess nitrate in Mississippi River water entering offshore areas is reported to contribute to low oxygen (hypoxia) conditions in the Gulf of Mexico. Excessive algal growth driven by the excess nitrogen results in a decrease in dissolved oxygen in bottom water. Reintroduction of Mississippi River waters into a Louisiana coastal wetland has the potential to reduce the amount of nitrate reaching offshore waters. In this study, reduction in the concentration of added NO₃^- was determined in sediment-water-columns collected from a wetland site in Breton Sound estuary receiving nutrient inputs from the Mississippi River. The capacity of a wetland to process nitrate in floodwater was determined in the laboratory. The rates of NO₃^- removal (determined from change in nitrate concentration in the floodwater) averaged 97 mg N m^-2 d^-1 over 16 d for a 1750-mg NO₃-N m^-2 addition, and 170 mg N m^-2 d^-1 over 16 d for a 3500-mg NO₃-N m^-2 addition. The total N₂O-N emissions from the 1750- and 3500-mg NO₃-N m^-2 additions were 19 and 54 mg N m^-2 accounting for 1.1% and 1.5% of the applied NO₃-N, respectively. Using the acetylene-inhibition technique, the average denitrification rate was determined to be 57 and 87 mg N m^-2 d^-1 (21 and 32 g N m^-2 yr^-1) during the most active denitrification period of 5 d after incubation for 1750 and 3500 mg NO₃^--N m^-2 of added nitrate in floodwater, respectively. The total N evolved over 11 d as N₂O + N₂ was equivalent to 436 and 921 mg N m^-2 (24.9% and 26.3%, respectively, of added N). Increasing the amount of NO₃^- applied to the overlying water increased the rate of NO₃^- loss and N₂O emission significantly. The thickness of the oxidized surface sediment layer was also influenced by the NO₃^- application to the floodwater with a significant linear correlation between nitrate addition and thickness of the oxidized layer (r = 0.9998, p = 0.01). This study indicates that wetlands receiving diverted Mississippi River water have the potential to process and remove NO₃^- in the river water, reducing the amount of NO₃^- reaching to offshore areas.     

Hepatoprotective activity of 1-(4-(Dimethylamino)Benzylidene)-5-(2-Oxoindolin-3-ylidene) Thiocarbohydrazone in rats

The aim of the present study was to evaluate the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone, a novel isatin derivative against carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats. Hepatic damage was induced by administration of CCl₄ (1 ml/kg, b.w., p.o.) in combination with liquid paraffin (1:1) as a single dose. The hepatotoxic rats were treated with test compound at doses of 50 or 100 mg/kg for three days and liver damage biomarkers, including activities of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), serum alkaline phosphatase (ALP), and levels of total serum bilirubin (TB) measured in blood samples. Results demonstrated that treatment with test compound at doses of 50 or 100 mg/kg to hepatotoxic rats produced a significant dose-dependent reduction of elevated SGOT, SGPT, ALP activities and TB levels indicating a hepatoprotective effect that was confirmed by histopathological examination of liver tissues. The study results confirmed the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone in rats.     

叠氮化钠对亚硝酸根分解能力的探讨

分析了采用叠氮化钠修正法测定水中溶解氧时，对水中亚硝酸根含量与叠氮化钠加入量的关系。     

灭幼脲(Ⅲ)在水相中光解产物的鉴定

采用HPLC—UV及GC—MS技术鉴定了灭幼脲(Ⅲ)在水相中的表观光解产物,通过分析表观光解反应与暗反应产物的相对含量,确认对氯苯基异氰酸酯和邻氯苯甲酰胺是灭幼脲(Ⅲ)在永相中光解的主要产物。另外,依据反应产物的组成和相对含量,对灭幼脲(Ⅲ)在水相中的光解反应速率常数作了估算。     

Allocation of herbivory-induced hydroxamic acids in the wild wheat Triticum uniaristatum

Summary. We characterized the induction of hydroxamic acids (Hx) by aphid infestation in the wild wheat Triticum uniaristatum by addressing the following questions: i) Do different leaves have similar responses to aphid damage?, ii) Is the Hx induction localized or systemic?, iii) How long does the induction last?, and iv) Is the degree of damage related to the magnitude of induced Hx? Based on earlier results on this wheat/aphid system (lack of costs of Hx induction) we expected to find the plant exhibiting cost-saving patterns of response to herbivory. Aphid infestation in the primary leaf led to induced levels of Hx, but no differences in Hx levels were found after infestation of the secondary leaf. Induction of Hx was restricted to the infested leaf (primary leaf). Induced Hx levels exhibited by the primary leaf at the end of aphid infestation were not observed 2 days later. Finally, different aphid densities (between 10 and 40 aphids per leaf) did not produce significant differences in Hx levels in infested primary leaves. Characteristics of Hx induction by aphid infestation in T. uniaristatum partially support the expected cost-saving patterns in the allocation of induced defenses. Received 15 January 1997; accepted 7 July 1997.     

Oviposition of carrot fly (Psila rosae) in response to foliage and leaf surface extracts of host plants

Summary. Foliage of twelve host and two non-host species and surrogate leaves treated with the respective leaf extracts were presented to laboratory populations of the carrot fly (Psila rosae) in oviposition choice assays. The stimulatory activity of dichloromethane surface extracts and the diethyl ether fraction of hot water extracts did not reflect accurately the differences in acceptability observed among intact leaves. A better correlation was found using hexane extracts prepared in a microwave oven. Two out of five fractions of this crude hexane extract obtained by silica gel column chromatography stimulated oviposition. The diethyl ether fraction, which contained the previously identified oviposition stimulants (propenylbenzenes, furanocoumarins, polyacetylenes), could account for only a minor part of the variation in the acceptability of host leaves. The preference hierarchy for intact leaves corresponded better to the ranking of species according to activity of the methanolic fraction, which apparently contains unknown stimulatory compounds.? The water fractions of the hot water extracts were shown to reduce egg-laying underneath surrogate leaves treated with a stimulatory extract. This oviposition-deterring effect was particularly strong with the non-preferred species Pimpinella major, which is also highly resistant in the field. Hence, unidentified inhibitory compounds may also contribute to differential accept ability of host plants. It is concluded that antixenotic (non-preference) resistance of host plants to carrot fly attack depends on complex mixtures of semiochemicals. Received 11 June 1997; accepted 26 November 1997.