白色杆菌属一新种的分离鉴定及其系统发育学分析

从热带土壤中分离到一株好氧、革兰氏阳性、不产芽孢的杆状菌株F8,该菌株含有MK11为主要醌组份;细胞壁肽聚糖的氨基酸组分为2,4氨基丁酸和γ氨基丁酸等;细胞壁糖组分为鼠李糖、半乳糖和葡萄糖;DNA的G+C含量为68mol%。16SrRNA基因测序和系统发育学分析的结果表明,菌株F8与驹形白色杆菌(Leucobacter komagatae)亲缘关系最近,其16S rRNA基因的同源率为96%。两者的总DNA杂交率为62%,生理生化特征也有差异,故可把菌株F8定为一个新种,即热带白色杆菌(Leucobacter tropicalissp.nov.)。     

枯草芽孢杆菌中性内切β-甘露聚糖酶的纯化及性质

枯草芽孢杆菌(Bacillus subtilis)BM9602产生的中性内切β甘露聚糖酶(endoβ1,4Dmannan mannanohydrolase,EC,3.2.1.78)经硫酸铵分级沉淀、DEAE纤维素(DE22)离子交换柱层析,得到电泳纯的样品,提纯了455倍,收率为59%。用SDSPAGE测得该酶的分子量为35kD。用PAGEIEF测得其等电点pI为45。酶反应的最适pH为5.8,最适温度为50℃。该酶在pH60～80,50℃以下稳定。金属离子Hg2+和Ag+对酶活性强烈抑制。酶对槐豆胶、羟丙基瓜胶、田菁胶和魔芋粉的Km值分别为38、149、113和24mg/mL,Vmax值分别为245、865、384和198μmol.min-1mg-1。酶水解甘露聚糖为甘露寡糖(不含单糖)。     

杀鞘翅目苏云金芽孢杆菌新菌株及其杀虫剂的研究

从中国土壤中分离出2株杀鞘翅目昆虫的苏云金芽孢杆菌(Bacillus thuringiensis) YM03及SHQ11-10。YM03的血清型为H8a8b,SHQ1110的H血清型未知。二菌株皆产近菱形的薄扁伴孢晶体,分别含68～70kD和65kD的晶体蛋白质。毒力生物测定证明对柳蓝叶甲(Plagiodera versicolora)及马铃薯甲虫(Leptinotarsa decemlineata)有高毒效。发酵性能良好。YM03粉剂田间防治马铃薯甲虫有高效。稀释400倍喷雾,防治效果达94.6%。     

鞘氨醇单胞菌PY3菲降解基因的克隆及序列分析

将菲降解菌鞘氨醇单胞菌(Sphingomanas sp.)PY3的DNA片段与pUC119质粒连接后,转化大肠杆菌JM109,经筛选得到两个质粒,分别命名为pUp1(带有23kb外源DNA片段)和pUp2(带有39kb外源DNA片段)。pUp 1的DNA含有2个ORF。ORF 1由275个氨基酸组成,与恶臭假单胞菌(Pseudomonas putida)F1的甲苯水解酶及菌株Pseudomonas CF600的甲苯水解酶在氨基酸水平上有47%的同源性。ORF 2由327个氨基酸组成,与嗜热脂肪芽孢杆菌(Bacillus stearothermophilus)的邻苯二酚双加氧酶(phe B)及紫红红球菌(Rhodococcus rhodochrous)CTM的邻苯二酚双加氧酶(C23O)在氨基酸水平上分别有57%和44%的同源性。     

绿色荧光蛋白基因标记野生型生防枯草芽孢杆菌的研究

根据绿色荧光蛋白基因和枯草芽孢杆菌木糖诱导型启动子PxylR 序列,分别设计两对特异引物primers PxyF/R和primers gfpF/R,扩增获得了完整的启动子PxylR和-gfp基因序列。进一步以上述产物混合物为模板,以primer PxyF/primer gfpR做引物进行重迭PCR,获得了PxylR-gfp重组翻译融合表达盒。经SphⅠ和KpnⅠ完全酶切后,将PxylR-gfp表达盒分别插入大肠杆菌_苏云金芽孢杆菌穿梭载体pHT315和大肠杆菌枯草芽孢杆菌穿梭载体pRP22。相应的重组表达质粒pGFP315和 pGFP22转化枯草芽孢杆菌感受态细胞。前者在标准菌株168中得到良好发光表型,后者则在标准菌株168和野生目标菌株B916中均得到良好的发光表型。室内平板抑菌实验结果显示B916生防效果与出发菌株没有明显差异,遗传稳定性研究表明连续稀释培养约175代后,工程菌株稳定性为94%,质粒丢失频率低于3.5×10^-4/代。     

一个可降解直链烷基苯磺酸盐的新种

本文鉴定了一株可完全降解直链烷基苯磺酸盐（Linear Alkylbenzene Sulphonate,简称LAS）的菌株GZ6。革兰氏染色阴性,细胞为杆状或短杆状,大小为0.5μm～0.8 μm×1.0μm～2.0 μm,其生长pH范围为pH6.0～10.0,最适生长pH为7.0,生长温度范围为4℃～40℃,最适生长温度为30℃。生化特征测定除过氧化氢酶、尿酶、精氨酸脱羧酶反应为阳性,其它均为阴性。可利用Chloridazon、安替比林（antipyrin）以及LAS等为碳源。不能利用大多数糖醇。醌组分以泛醌Q10为主。菌体脂肪酸主要为C18∶1、C16∶0及C16∶1。DNA中G+C mol％含量为7010。16S rRNA 序列分析表明菌株GZ6 与其亲缘关系最近的菌株Phenylobacterium immobile DSM1986T序列相似值为9749％,DNADNA杂交率为40%。菌株GZ6具极生鞭毛,可运动,两者在细胞形态有很大差异。故将菌株GZ6定为苯基杆菌属的新种可动苯基杆菌（Phenylobaterium mobile） GZ6。     

苏云金杆菌辅助蛋白P20对杀虫晶体蛋白Cry1Ab表达的影响

苏云金杆菌(Bacillus thuringiensis, 简称Bt)杀虫晶体蛋白Cry1Ab因其C半端缺少了一段含4个半胱氨酸的氨基酸序列而导致蛋白的不稳定,报道苏云金杆菌辅助蛋白P20帮助Cry1Ab蛋白的表达及晶体的形成。利用穿梭载体pHT3101构建3个表达质粒,即pT1B、pP1B和pDP1B,3个质粒都含有cry1Ab基因,不同在于pT1B没有p20基因,pP1B含有p20全基因,而pDP1B不仅含有p20全基因,且在p20基因前插入cry1A?启动子。分别将这3个表达质粒经电转化到苏云金杆菌晶体缺陷型菌株CryB中,获得转化菌株T1B、P1B和DP1B。Western blot表明cry1Ab基因在这3株菌中均表达了130 kD的蛋白,部分降解为大约60 kD的蛋白。蛋白定量分析显示,3株菌130 kD蛋白量的比为1∶1.4∶1.5,降解后的60 kD蛋白量的 比为1∶1.1∶1.6,Cry1Ab蛋白总量的比为1∶1∶2∶1.6。镜检发现,Cry1Ab在3株菌中都形成典型的菱形晶体,其晶体大小为T1B Helicoverpa armigera）均具有明显的杀虫活性,三者的LC₅₀差异不显著。研究表明,P20对cry1Ab基因的表达和晶体形成均有帮助,P20表达量的多少可能是导致Cry1Ab蛋白最终产量有所不同的因素。     

枯草芽孢杆菌寡聚1，6-葡萄糖苷酶基因的克隆及其在大肠杆菌中的表达

本研究用鸟枪法构建了枯草芽孢杆菌(Bacillus subtilis)HB002的基因组文库,经平板法筛选得到了六株能水解合成底物对硝基苯αD葡萄糖吡喃糖苷的阳性克隆,经鉴定均含克隆了寡聚1,6葡萄糖苷酶基因的重组质粒(命名为pHBM001～pHBM006)。选择pHBM003,对其插入片段测序分析,此片段内有一编码561个氨基酸的开放阅读框,该蛋白质的计算分子量为65985kD。HB002的寡聚1,6葡萄糖苷酶的氨基酸序列与Bacillus sp.和凝结芽孢杆菌(Bacillus coagulans)的寡聚1,6葡萄糖苷酶的氨基酸序列一致性分别为81%、67%,相似性分别为89%、79%。从pHBM003中扩增出寡聚1,6葡萄糖苷酶基因,克隆到pBV220上,转化大肠杆菌(Escherichia coli)DH5α,得到三个能水解对硝基苯αD葡萄糖吡喃糖苷的阳性克隆HBM0031～HBM0033,将此三个菌株热诱导表达,SDSPAGE电泳可检测到特异表达的蛋白质,其中HBM0031、HBM0032表达的蛋白约66kD,为完整的寡聚1,6葡萄糖苷酶,而HBM0033表达的蛋白质偏小;表达的蛋白质均有寡聚1,6葡萄糖苷酶活性。     

土壤来源的五个苏云金芽孢杆菌新亚种的鉴定

从中国土壤中分离的大量苏云金芽孢杆菌菌株中鉴定出H42、H43、H56、H60及H62等5种新H血清型,并进行了形态、培养特征、生化反应、晶体蛋白质成分及毒力特性等项检测鉴定,鉴定了5个苏云金芽孢杆菌新亚种： Bacillus thuringiensis subsp. jinghongiensis (H42), B.thuringiensis subsp. guiyangiensis (H43),B.thuringiensis subsp. rongseni(H56),B.thuringiensis subsp. pingluonsis(H60)及B.thuringiensis subsp. zhaodongensis(H62) 。毒力生物测定证明5个新亚种的代表菌株对棉铃虫(Heliothis armigera)\,小菜蛾(Plutella xylostella)\,柳蓝叶甲(Plagiodera versicolora)幼虫均无毒力。H42、H43、H56、H60对埃及伊蚊(Aedes aegypti)\,斑须按蚊(Anopheles stephensi)及尖音库蚊(Culex pipiens)亦均无毒;H62对埃及伊蚊无毒,但对尖音库蚊与斑须按蚊有低毒。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.