三江源地区不同退化程度草地的土壤放线菌区系

用不同分离方法,对三江源地区不同退化程度草地土壤放线菌的数量和多样性进行了比较.从5份土样中共分离放线茵178株,根据表型特征和16S rRNA基因序列分析,分别归入7个已知属:小单孢菌属(Micromonospora)、原小单孢菌属(Promicromonospora)、诺卡氏菌属(Nocardia)、假诺卡氏菌属(Pseudonocardia)、游动放线菌属(Actinoplanes)、韩国生工茵属(Kribbella)和链霉菌属(Streptomyces).其中链霉菌属分离菌株可归入7个表型类群.发现轻度退化高寒草原的土壤放线菌数量,丰度和多样性高于重度退化高寒草原;针茅高寒草原的土壤放线菌数量和多样性高于蒿草高寒草甸,而其中链霉菌的种类低于后者.表明高寒草地的退化程度与其中土壤放线茵的数量和多样性呈负相关.     

四川阿坝不同生境绿绒蒿内生放线菌多样性

【背景】目前国内外对绿绒蒿内生放线菌的研究较为鲜见,利用可培养和免培养的方法可以丰富绿绒蒿内生放线菌资源。【目的】药用植物绿绒蒿生长于高海拔地区,而四川阿坝州生态环境适合绿绒蒿的生长,本研究旨在探究绿绒蒿内生放线菌的多样性及群落结构。【方法】从阿坝州6个不同地理位置采集的药用植物绿绒蒿,经严格的表面消毒后,用可培养和PCR-DGGE技术相结合的方法对其内生放线菌进行分析。【结果】可培养方法分析表明不同器官放线菌数量为根叶茎花;16S r DNA限制性内切酶片段长度多态性(RFLP)分析将供试菌株分为7个遗传群,系统发育分析表明,绿绒蒿内生放线菌可分为3簇遗传群落,链霉菌属(Streptomyces)为优势菌群,占总数的50%,还包括北里孢菌属(Kitasatospora)和厄氏菌属(Oerskovia),其中茎分离的放线菌多样性最好。不同地理位置的绿绒蒿经过PCR-DGGE技术分析表明,采样点松潘尕力台的根、茎、叶多样性指数最好,红原安曲乡的花多样性指数最好,而同一地理位置绿绒蒿内部组织之间总体来看茎和花的多样性指数最好,通过测序条带系统发育发现绿绒蒿内生放线菌可分为8簇遗传群落,红球菌属(Rhodococcus)为优势菌群,占总数的70%,还包括棒杆菌属(Corynebacterium)、诺卡氏菌属(Nocardia)、微球菌属(Micrococcus)、栖霉菌属(Mycetocola)、微杆菌属(Microbacterium)、假诺卡氏菌属(Pseudonocardia)和链霉菌属(Streptomyces)。【结论】绿绒蒿根、茎、叶、花组织中具有丰富的多样性,能够为以后活性物质和药用功效的研究奠定基础。     

青海盐碱环境中具抗肿瘤活性放线菌的筛选和多样性研究

从我国青海省采集盐碱土样或泥样,用添加1.0~3.0mol/L NaCl的GPY琼脂培养基和ISP2琼脂培养基分离到145株典型放线菌菌株。采用6种肿瘤细胞株对分离菌株的发酵产物进行体外筛选,得到26株抗肿瘤活性阳性菌株(17.9%),19株为拟诺卡氏属(Nocardiopsis)菌株,7株为链霉菌属(Streptomyces)菌株。在抗肿瘤活性、形态特征、生理生化特性和全细胞水解物氨基酸组分分析等实验结果的基础上,选取差异较大的8株抗肿瘤活性阳性菌株进行16S rRNA基因序列测定和系统发育多样性分析。结果表明,2株属于链霉菌属(Streptomyces)的1个已知物种和1个潜在新种;6株属于拟诺卡氏菌属(Nocardiopsis),可能代表该属的4个新种。研究表明青海盐碱环境中存在产生抗肿瘤活性物质的重要放线菌资源,也提示其中蕴藏着较丰富的微生物多样性。     

广西沿海地区红树林根系土壤中放线菌的分离与鉴定

本研究通过分离纯培养,从广西北海及防城港红树林根系土壤中分离出放线菌并提取其总DNA,用放线菌通用引物对获得菌株的16S rDNA进行PCR扩增,对获得的扩增产物进行DNA序列测定及菌株鉴定.研究结果表明,从红树林根系土壤样品中分离出15株典型放线菌菌株.16S rDNA测序比对鉴定结果显示,15株典型放线菌菌株中有12株属于链霉菌属(Streptomyces),是常见菌属;3株属于拟诺卡氏菌属(Nocardiopsis),为稀有放线菌.本研究分离纯化获得15株典型放线菌,初步揭示了广西沿海地区红树林土壤中放线菌的多样性.     

川楝内生放线菌的分离及多样性研究

【目的】分离四川省各个地区川楝内生放线菌并研究其物种多样性。【方法】应用7种选择性分离培养基分离样品根、茎、叶、树皮和果实中的内生放线菌,采用16SrRNA基因RFLP分析代表菌株多样性。【结果】研究共获得403株内生放线菌。不同地点、不同植株部位、不同培养基分离得到的内生放线菌数目均有差异。广元采集的样品分离得到的数目最多,为86株;最少的是绵阳,仅有12株。从植物表皮中分离到148株放线菌,占获得菌株总数的36.7%;而从果中分离到31株,仅占获得菌株总数的7.6%;虽然从根部分离到的数量也很少,但是其出菌率却是最高的。5号和3号培养基的分离效果最为理想。16S rRNA基因RFLP分析结果显示所有供试菌株在68%的相似性上聚在一起,在84%的相似水平上分成了10个遗传类型。代表菌株的16SrRNA基因序列测定及系统发育分析结果表明:分离得到的放线菌包括4个属,分别是链霉菌属(Streptomyces)、北里孢菌属(Kitasatospora)、节杆菌属(Arthrobacter)、克里布所菌属(Kribbella)。其中,链霉菌是优势类群,占代表菌株数目的比例高达91%,而稀有放线菌的比例只有9%。【结论】研究发现的川楝内生放线菌主要属于链霉菌属(Streptomyces)、北里孢菌属(Kitasatospora)、节杆菌属(Arthrobacter)、克里布所菌属(Kribbella)。     

罗布泊盐湖可培养放线菌多样性及PKS Ⅱ功能基因筛选

目的:挖掘新疆罗布泊盐湖可培养放线菌的资源和探索该环境放线菌产生Ⅱ型聚酮合成酶(PKS)基因的潜能。方法:从新疆罗布泊盐湖采集到10份样品,采用不同盐浓度的9种选择性培养基分离放线菌,并通过PCR技术扩增其16S r DNA序列、聚酮合成酶(PKS)基因分子筛选,测序后进行系统发育分析和BLAST比较研究。结果:试验结果共得42株放线菌,包括6个属,链霉菌属(Streptomyces)和拟诺卡氏菌属(Nocardiopsis)的类群最多,糖霉菌属(Glycomyces)、放线多孢菌属(Actinopolyspora)、微球菌(Micrococcus)和栖白蚁菌属(Isoptericola)的菌株相对较少。研究获得新的放线菌分类单元,其16S r DNA基因序列与已知菌株的序列相似性低于97%。42株放线菌中共有29株产生PKSⅡ基因,主要是链霉菌属和拟诺卡氏菌属。结论:研究结果表明罗布泊盐湖放线菌具有丰富的资源多样性和较强合成抗生素的潜在能力。     

嗜酸丝状放线菌的选择性分离与多样性

摘要:【目的】针对酸性土壤中的嗜酸丝状放线菌,建立有效的选择性分离方法,并了解其多样性。【方法】用不同的样品预处理方式和分离培养基,并添加不同的抑制剂进行分离;根据放线菌的菌落数和出菌率确定最佳分离方法组合。采用最佳分离方法对从江西采集的17份酸性土壤样品进行分离;根据培养特征对分离菌株进行分群,进一步通过对各类群的显微形态观察和pH梯度生长实验确定代表菌株;对代表菌株进行16S rRNA基因序列分析研究其多样性。【结果】嗜酸丝状放线菌的最佳分离方法为：土壤样品经分散差速离心预处理后,涂布添加了放线菌酮、制霉菌素和萘啶酮酸（各50 mg/L）的GTV培养基。用此方法共分离到放线菌369株,归为10个不同的颜色类群,其中6.6%为严格嗜酸放线菌,72.4%为中度嗜酸放线菌,21.0%为耐酸放线菌。52株嗜酸放线菌代表菌株分布于放线菌目中的12个属：链霉菌属(Streptomyces)、小单孢菌属(Micromonospora) 、诺卡氏菌属(Nocardia)、野野村菌属(Nonomuraea) 、韩国生工属(Kribbella) 、小双孢菌属(Microbispora)、马杜拉菌属(Actinomadura)、拟无枝菌酸菌属(Amycolatopsis)、指孢囊菌属(Dactylosporangium)、伦茨氏菌属(Lentzea)、游动四孢菌属(Planotetraspora) 和链嗜酸菌属(Streptacidiphilus),其中链霉菌分离菌株在系统发育树上形成12个不同的进化类群。【结论】所建立的选择性分离方法可用于土壤嗜酸丝状放线菌的高效分离;江西酸性土壤含有丰富多样的嗜酸丝状放线菌种属。     

百部内生放线菌的分离、分类及次级代谢潜力

【目的】以对叶百部块根为材料分离内生放线菌,并对分离菌株进行分类、抗菌活性和次级代谢产物合成基因研究。【方法】样品经过严格的表面消毒,选用4种培养基分离百部内生放线菌;分离菌株通过形态观察和16S rRNA序列分析进行分类鉴定;采用琼脂移块法测试分离菌株的抗菌活性;通过PCR检测分离菌株的PKS/NPRS和卤化酶基因;使用HPLC-UV/VIS-ESI-MS/MS分析发酵产物。【结果】从6个样品中获得18株内生放线菌,分属链霉菌属(Streptomyces)、小单孢菌属(Micromonospora)、假诺卡氏菌属(Pseudonocardia)和甲基杆菌属(Methylobacterium)。分离菌株绝大部分具有抗菌活性和次级代谢产物合成基因,其中13株对耐药金黄色葡萄球菌和/或绿脓杆菌有拮抗活性,17株具有PKS/NRPS基因,8株菌具有卤化酶基因,且卤化酶阳性代表菌株的发酵产物具有抗细菌活性和卤代化合物特征。【结论】百部作为一种传统中药,其内生放线菌以链霉菌和小单孢菌为主,在次级代谢产物合成方面具有很好的潜力,可作为一类重要微生物资源进行活性产物开发。     

8种贵州药用植物内生放线菌的分离及多样性研究

【背景】药用植物内生菌能产生多种活性较好的次级代谢产物,是新抗生素发现的重要来源。目前,药用植物内生菌的研究主要集中在内生真菌,内生放线菌研究相对较少,是一个尚未充分开发的新领域。【目的】研究贵州药用植物内生放线菌多样性,以期发现新种放线菌或产新活性物质的放线菌,为微生物药物研究奠定基础。【方法】药用植物样品表面消毒后用粉碎机粉碎,采用9种不同分离培养基分离放线菌;通过提取放线菌基因组DNA,PCR扩增16S rRNA基因序列,测定序列并提交EzBioCloud数据库进行序列比对,构建系统进化树,进行内生放线菌多样性分析。【结果】通过形态特征初步排重,从8种药用植物样品中共分离得到内生菌62株,测定其16S rRNA基因序列,序列比对结果表明其中的57株菌分布于放线菌域的5目8科16属,分别是短小杆菌属(Curtobacterium)、链霉菌属(Streptomyces)、微杆菌属(Microbacterium)、纤维单胞菌属(Cellulomonas)、植物杆菌属(Plantibacter)、原小单孢菌属(Promicromonospora)、动球菌属(Kineococcus)、壤球菌属(Agrococcus)、沼杆菌属(Patulibacter)、气微菌属(Aeromicrobium)、拉贝达氏菌属(Labedella)、叶居菌属(Frondihabitans)、冷杆菌属(Frigoribacterium)、节杆菌属(Arthrobacter)、动孢菌属(Kineosporia)、Amnibacterium属,其中短小杆菌属(Curtobacterium)为优势菌属,菌株M8JJ-5和M2KJ-4的16S rRNA基因序列分别与有效发表菌株AmnibacteriumkyonggienseKSL51201-037T(FJ527819)和Aeromicrobiumfastidiosum DSM10552T (Z78209)的相似性最高,相似性分别为97.29%和98.95%,可能为潜在新物种。【结论】贵州药用植物中蕴藏着多样性丰富的放线菌且具有从中发现新放线菌的潜力,能为新抗生素的发现提供菌种储备,也为今后对该地区放线菌资源的认识和开发利用提供理论依据。     

云南金铁锁根可培养放线菌多样性及其抗菌活性研究

【目的】探索云南金铁锁根部可培养放线菌资源及筛选高抗病原菌活性菌株。【方法】以云南4个地方金铁锁的根为研究对象,采用不同温度预处理及14种分离培养基对其进行放线菌分离;选用74株内生放线菌菌株,以5种病原菌为指示菌,使用倒置法测定供试放线菌的抗菌活性。【结果】从金铁锁根部分离获得121株内生放线菌,基于16S rRNA基因序列比对和系统发育分析,将其归属于10个目、15个科和24个属,其中链霉菌(Streptomyces)为绝对优势菌群,其后依次为诺卡氏菌属(Nocardia)、小单孢菌属(Micromonospora)和分枝菌酸小杆菌属(Mycolicibacterium)。分离效果最好的培养基为D4 (酵母粉0.3 g,干酪素0.3 g,葡萄糖0.3 g,骨粉0.3 g);最优的预处理温度为80℃;74株内生放线菌中的37株对至少一种指示病原菌具有抑制活性,且活性强的主要类群为链霉菌属。【结论】金铁锁根部蕴藏着丰富的放线菌种质资源,且蕴含着具有产次级代谢产物能力的菌株,这将为后续的医药及农业生产提供了丰富的菌种资源,同时为其栽植、保护、开发及应用提供了一定的基础数据和理论依据。     

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.     

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.     

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.     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

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.     

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.     

（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。