碱性纤维素酶革兰氏阴性菌株筛选及酶学性质研究*

用CMC平板筛选方法,从造纸厂碱性淤泥中获得透明圈直径大于30mm的产碱性纤维素酶革兰氏阴性菌H8005。液体摇瓶培养产生碱性CMC酶活力高达4.2 IU/mL。酶学性质初步研究显示,H8005产生的CMC酶反应的pH值以8.0左右为适;在碱性条件下具有较高的酶活和一定的稳定性;反应温度以55℃左右为宜;且具有较好的温度稳定性。Mn²⁺与Fe³⁺对酶反应有促进作用,Cu²⁺和Pb²⁺对酶反应有抑制作用。该菌产生的纤维素     

产中性纤维素酶耐碱芽孢杆菌的筛选及酶学性质研究

采用CMC碱性平板筛选方法,从造纸厂碱性淤泥中获得产中性纤维素酶的耐碱枯草芽孢杆菌C3004。根据其形态特征、生理生化特性和16S rRNA序列分析鉴定该菌株为枯草芽孢杆菌,并命名为Bacillus subtilis C3004。液体摇瓶培养24 h产生CMC酶活力达46.6 U/mL。酶学性质初步研究显示,CMC酶反应的pH值以7.0左右为适;在弱酸和碱性条件下也具有较高的酶活和一定的稳定性;反应温度以50℃左右为宜;且具有较好的热稳定性。Mn~(2+)与Fe~(3+)对酶反应有促进作用,Cu~(2+)、Mg~(2+)和Zn~(2+)对酶反应有抑制作用。该菌可在碱性(pH 8.5～10)条件下培养,具有不易被杂菌污染的特点。     

产低温纤维素酶放线菌的筛选、鉴定及酶学性质初步研究

从青藏高原采集的牦牛粪中,经过CMC平板分离得到一株产低温纤维素酶能力较强的放菌Tibet-YD5227-2,经16S rDNA序列比对分析将其初步鉴定为链霉菌属(Streptomyces sp.),目前尚无链霉菌产低温纤维素酶的研究报道。Tibet-YD5227-2液体摇瓶培养产生低温CMC酶活力高达145U/mL,最适产酶温度25℃,最适产酶pH值为8.0。酶学性质初步研究显示,Tibet-YD5227-2产生的CMC酶反应温度以35℃左右为适,反应的pH值以8.0左右为适,该菌株所产的纤维素酶在中碱性条件具有较强的稳定性;K+、Fe2+、Mg2+对酶反应有促进作用,Hg2+、Cu2+对酶反应有抑制作用。     

产碱性纤维素酶兼性厌氧菌株的筛选和酶学性质的初步研究

用CMC平板筛选方法, 从造纸厂碱性土壤中获得产碱性纤维素酶兼性厌氧菌株LZ-5, 革兰氏阴性, 经鉴定为弧菌属(Vibrio sp.)中的一个种。液体摇瓶培养产生碱性纤维素酶活力高达5.8 U/mL。酶学性质初步研究显示, LZ-5产生的纤维素酶最适反应温度为40℃, 最适反应pH值为9.0, 在碱性条件下具有较高的酶活性和较好的稳定性。经传代培养证实该菌株遗传性能稳定。     

产碱性纤维素酶兼性厌氧菌株的筛选和酶学性质的初步研究

用CMC平板筛选方法,从造纸厂碱性土壤中获得产碱性纤维素酶兼性厌氧菌株LZ-5,革兰氏阴性,经鉴定为弧菌属(Vibrio sp.)中的一个种.液体摇瓶培养产生碱性纤维素酶活力高达5.8 U/mL.酶学性质初步研究显示,LZ-5产生的纤维素酶最适反应温度为40℃,最适反应pH值为9.0,在碱性条件下具有较高的酶活性和较好的稳定性.经传代培养证实该菌株遗传性能稳定.     

一株产纤维素酶细菌的分离鉴定及酶学特性研究

从采集的含腐烂树叶的土壤中,筛选到1株产纤维素酶能力较高的菌株JJ-3,经16S r RNA基因序列分析,鉴定该菌株为产酸克雷伯氏杆菌(Klebsiella oxytoca)。产酶条件及酶学特性研究表明:以滤纸为碳源、蛋白胨为氮源、初始p H为8.0的培养基中发酵3 d更利于纤维素酶的合成;菌株发酵液在中性和碱性条件下均有较高的滤纸酶活力,分别可达118.7 U/m L(p H7.0),167.8 U/m L(p H8.0)和120 U/m L(p H9.0);所产纤维素酶的最适酶反应p H为7.0,最适酶反应温度为40℃,对温度比较敏感,在p H7.0-8.0的范围内具有较好的稳定性,能满足中性和碱性纤维素酶的要求。     

有机复合物H对纤维素CMC酶活的影响

采用3,5-二硝基水杨酸(DNS)为显色剂,CMC为底物,测定纤维素酶的酶活。考察了在不同的酶促反应温度、pH值、底物浓度、反应时间等反应条件下,有机复合物H对纤维素酶CMC酶活(CMCA)的影响。结果表明,有机复合物H对纤维素酶的CMCA活性有明显促进作用,且在不同条件下的促进效果有较大差异。     

1株高效降解纤维素的槲寄生内生真菌研究

利用刚果红-CMC平板染色法、DNS法从槲寄生内生真菌中筛选获得1株高效纤维素酶产生菌H-3-3,通过分析其菌落形态特征和18S rDNA序列的同源性,将菌株H-3-3鉴定为拟茎点霉属Phom opsissp.;对其酶学性质研究得到：槲寄生内生真菌H-3-3中CMC酶、β-葡糖苷酶、滤纸酶这3种组分酶最适温度均为50℃,β-葡糖苷酶活和滤纸酶活最适pH值均为4.8,CMC酶最适pH值为4.4;3种酶在30～45℃,pH4.0～8.0稳定性较强。金属离子Mn^2＋、Co^2＋、Mg^2＋和Ca^2＋对3组分酶都有不同程度的促进作用,其中以Co^2＋效果最佳;而Ba^2＋、Zn^2＋、Cu^2＋对3组分酶分均表现出明显的抑制作用。     

有机复合物H对纤维素酶促反应动力学特性的影响

采用3,5-二硝基水杨酸(DNS)为显色剂,滤纸和CMC为底物,测定纤维素酶的酶活.考察了在不同温度、pH值、反应时间、底物浓度等反应条件下,有机复合物H对纤维素酶滤纸酶活(FPA)和CMC酶活(CMCA)的影响.结果表明,有机复合物H对纤维素酶的FPA活性和CMCA活性均有一定的促进作用,且在不同条件下的促进效果有较大差异.     

一株碱性纤维素酶产生菌的分离、鉴定及酶谱分析

目的:从土样中分离株碱性纤维素酶高产菌株.方法:利用CMC平板初筛,然后利用摇瓶复筛,筛选酶活力高的菌株,对分离出的一株高产菌株进行了鉴定并对其所产酶进行了酶谱分析.结果:获得一株碱性纤维素酶高产菌株H12,酶活力达到1.96U/ml.结论:该菌株呈长杆状、革兰氏染色为阳性、产芽孢;16S rDNA基因序列为1 419bp,与短小芽孢杆菌16S rDNA基因序列具有最高的同源性,基于16S rDNA基因序列的同源性分析以及系统发育分析等方面的多相分类研究,鉴定菌株H12为为短小芽孢杆菌;碱性纤维素酶的酶谱分析只有一条水解条带,酶分子量在75kD左右.     

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.     

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.     

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。     

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.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。     

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.