26株具有细胞毒活性的海洋放线菌的系统发育研究

从海南红树林的海泥和海藻样品中分离得到26株具有细胞毒活性的放线菌(Actinomycetes),根据其形态学特征、生理生化特性及16SrDNA序列分析结果,确定菌株0617230属于小单孢菌属(Micromonospora),与Micromonosporaechinospora的相似性为97%。其余25株菌株属于链霉菌属(Streptomyces),其中菌株050643与其亲缘关系最近的Streptomycesviolaceolatus的相似性仅为96%;菌株061342与其亲缘关系最近的Streptomyceskasug-aensis、Streptomyceskasugaensis、Streptomycesmorookaensis的相似性仅为95%;菌株061303等11株菌株与其亲缘关系最近的Streptomyceskasugaensis、Streptomyceskasugaensis、Streptomycesmorookaensis的相似性仅为95%;因此它们可能是新种。     

分离于河口区芦苇湿地1株好氧反硝化菌的鉴定及其反硝化特性

【目的】筛选高效脱氮且N_2O释放量少的好氧反硝化细菌,并对菌株的反硝化特性进行研究,可为河口湿地富营养化水体的生物修复提供技术支撑。【方法】经BTB培养基初筛和反硝化能力测定,从辽河河口区芦苇湿地土壤中分离得到1株具有较高反硝化能力的好氧反硝化菌C3。经形态观察、生理生化鉴定和16S rRNA序列分析,对菌株进行鉴定。研究温度、碳源、pH及C/N对其生长量、反硝化能力及N2O释放的影响。【结果】筛选得到的高效好氧反硝化细菌C3,经鉴定属于假单胞菌属(Pseudomonas sp.)。反硝化特性研究结果表明,该菌最适碳源为柠檬酸三钠,在温度为30°C、pH为7.0、C/N为10时生长速率和脱氮效率最高且N_2O释放量较少。在此条件下,该菌在36 h内使NO_3~–由179.55 mg/L降至5.08 mg/L,脱氮率高达97.17%。该菌株在整个反硝化过程中中间产物N_2O的最大累积量较低,为0.22 mg/L。【结论】从湿地土壤中分离所得好氧反硝化菌C3为假单胞菌属的1个种(Pseudomonas sp.),该菌株在高效除氮和低N_2O累积方面均具有明显优势,对后续河口湿地富营养化水体治理具有重要意义。     

水霉拮抗放线菌的分离、筛选与鉴定

目的:以珍珠健康养殖水体底泥为材料分离放线菌,筛选对水产动物水霉病病原菌有抗菌活性的放线菌。方法:采用稀释涂布法,选用萘啶酮酸和放线菌酮双抗平板分离获得放线菌;以黄颡鱼和湘云鲫鱼卵水霉病原菌为靶标菌,采用琼脂块法测试所分离菌株抗水霉菌活性及其稳定性;对拮抗活性强的放线菌采用形态观察和16S r DNA序列分析进行分类鉴定。结果:从分离获得的27株放线菌中筛选出3株对水霉病原菌有拮抗活性的菌株QF1、DNC17和QHV2,其中QHV2抗菌活性与稳定性最好;形态学观察与16S r DNA序列分析结果表明QF1、DNC17和QHV2均属于链霉菌属(Streptomycete sp.),分别鉴定为Streptomyces diastatochromogenes、Streptomyces variabilis和Streptomyces collinus。结论:3株放线菌对水霉病原菌具有较好的拮抗活性,具有开发成抗水霉药物的潜在价值。     

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.     

一株海水异养硝化-好氧反硝化菌系统发育及脱氮特性

【目的】确定一株分离自海水的异养硝化-好氧反硝化菌的系统发育地位并探索其脱氮特性和机理,以期为解释异养硝化-好氧反硝化机理以及改进海水养殖及废水的生物脱氮工艺提供理论依据。【方法】通过形态观察、生理生化实验和16S rRNA基因序列分析,鉴定该菌株;通过测定菌株在不同无机氮源降解测试液中的生长和脱氮效率,分析其异养硝化和好氧反硝化性能。【结果】经鉴定该菌株属于盐单胞菌属(Halomonas);最适生长条件为盐度3%、pH 8.5、温度28℃、碳氮比10:1,在盐度为15%的培养液中仍能生长;可以同时去除氨氮、亚硝酸氮和硝酸氮,24 h时对NH4+-N、NO2--N、和NO3--N的去除率可分别达到98.29%、99.07%、96.48%,3种形态无机氮同时存在时,会优先利用NH4+-N,且总无机氮去除率较单一存在时更高,说明该菌株可实现同步硝化反硝化。【结论】该分离自海水的异养硝化-好氧反硝化菌属于盐单胞菌属(Halomonas),在高盐环境中仍能生长,同时具有高效的异养硝化和好氧反硝化能力,能够独立完成脱氮的全部过程。     

茅尾海桐花树根际放线菌的分离鉴定和抗菌活性研究

利用滤纸片扩散法,以大肠杆菌、蜡状芽胞杆菌和绿脓杆菌等为指示菌,对茅尾海桐花树根际土壤中分离的30株放线菌进行抑菌活性分析,发现其中有22株发酵液具有抗菌活性.经复筛有4株放线菌具有较强且广谱的抗菌活性,对大肠杆菌、蜡状芽胞杆菌和绿脓杆菌显示了较强的抑制活性,特别抑制临床多耐药菌肺炎克雷伯氏菌和鲍曼不动杆菌.通过形态特征、16S rRNA基因序列和生理生化分析,这4株放线菌属于链霉菌,其中S3、S4、S14分别与Streptomyces coelicolor (KF742497)、Streptomyces lateritius (AY999855)及Streptom yces variabilis (FJ486480)具有98.8％、98.6％、98.7％的相似性,S4在进化上与Streptomyces intermedius、Streptomyces silaceus和Streptomyces flavorectus在同一个分支,而S3和S14与其他菌株的进化关系较远,在生理生化及形态特征与相关的模式菌株有较明显差异,有可能是新的种.     

三株杀粘虫放线菌的分类鉴定

菌株YIM31331、YIM31333、YIM31355是从云南省丽江、中甸采集的土壤样品中分离得到的具有产杀粘虫活性物质菌株。根据其形态学特征、生理生化特性及16S rDNA序列分析结果,认为菌株YIM 31331属于链霉菌属的Streptomyces subrutilus,YIM31333属于指孢囊菌属Dactylosporangium aurantiacum,YIM31355属于链孢囊菌属Streptosporangium vulgare。     

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。     

灯盏花产黄酮内生放线菌筛选及产黄酮能力的初步研究

通过黄酮类物质特异颜色反应和可见分光光度法,筛选产黄酮的灯盏花内生放线菌,研究灯盏花产黄酮内生放线菌在PDA、高氏1号和淀粉3种培养基上的产黄酮能力。结果表明:59株灯盏花内生放线菌中,8株菌的镁粉+浓盐酸、氯化铝、浓氨水3种颜色反应均成阳性,能够产生黄酮。形态学观察初步鉴定这8株菌均为链霉菌属(Streptomyces)。3种培养基中,在PDA培养基上灯盏花产黄酮内生放线菌的菌丝体生物量、黄酮含量和产量较高。8株灯盏花产黄酮内生放线菌中,菌株RA′1-7生长较好,菌株ELA′3-2和RA2-1菌丝体黄酮含量较高,菌株ELA′3-2菌丝体黄酮产量较高。     

人参根际微生物的研究——I.菌株的筛选及功能的测定

本文报导了从人参根面、根际土壤中,分离的细菌和放线菌的抗病,刺激作用及分布规律。其放线菌均属于Streptomyces属。筛选出的菌株不仅对人参锈腐病菌、根腐病菌具有拮抗作用,同时对人参、水稻幼苗及食用菌的生长也有刺激作用。     

Fighting climate change: soil bacteria communities and topography play a role in plant colonization of desert areas

Global warming has exacerbated desertification in arid regions. Exploring the environmental variables and microbial communities that drive the dynamics of geographic patterns of desert crops is important for large-scale standardization of crops that can control desertification. Here, predictions based on future climate data from CMIP6 show that a steady expand in the suitable production areas for three desert plants (Cistanche deserticola, Cynomorium songaricum and Cistanche salsa) under global warming, demonstrating their high adaptability to future climate change. We examined the biogeography of three desert plant soil bacteria communities and assessed the environmental factors affecting the community assembly process. The α-diversity significantly decreased along elevated latitudes, indicating that the soil bacterial communities of the three species have latitude diversity patterns. The neutral community model evaluated 66.6% of the explained variance of the bacterial community in the soil of desert plants and Modified Stochasticity Ratio <0.5, suggesting that deterministic processes dominate the assembly of bacterial communities in three desert plants. Moreover, topography (longitude, elevation) and precipitation as well as key OTUs (OTU4911: Streptomyces eurythermus and OTU4672: Streptomyces flaveus) drive the colonization of three desert plants. This research offers a promising solution for desert management in arid areas under global warming.     

Lignocellulose degradation and crude protein formation by three ligninolytic Streptomyces strains

Streptomyces strains (11A, 21B and 31C) were grown on guinea grass lignocellulose and their ability to decompose lignocellulose was monitored. All three Streptomyces strains caused lignocellulose weight losses ranging from 27 to 34%. The three Streptomyces strains were also found to metabolize between 27 and 40% of the lignin component and 22–29% of the carbohydrate component of lignocellulose over the 12 week incubation period. Crude protein increases of degraded guinea grass lignocellulose were between 10–1 and 14–5% over the same period.     

Latitudinal pattern in plant composition along the Peruvian and Chilean fog oases

Fog oases in western South America (locally named lomas) are distributed in a kind of fragmented or patchy way into the coastal desert. Their origin, as well as their current ecological connections in terms of species' dispersal capability, remains an open question. We analyzed the latitudinal pattern in plant species and phylogenetic similarities of 13 lomas, which cover the latitudinal extent of these habitats, from 7°58′ to 26°15′ S. A data-set of 1004 species from available checklists was considered. Plant species composition and phylogenetic relationships among lomas were analyzed by non-metric multidimensional scaling. Our results show three main groups of lomas (northern Peruvian, southern Peruvian, and North-Central Chilean lomas) that are aligned along a complex, nonlinear north–south gradient in ordination space. The weak species overlap between Peruvian and Chilean lomas, together with the higher content in endemic species of the Chilean communities, supports the hypothesis that, at least recently, species composition of the three main groups of lomas has been shaped by desert barriers limiting plant dispersal.     

内蒙古西鄂尔多斯地区半日花荒漠群落特征及其分类

半日花(Helianthemum songaricum)为亚洲中部特有种和古地中海残遗植物, 其群落为内蒙古西鄂尔多斯地区的特有荒漠植物群落。该文以2016-2017年野外调查数据为基础, 结合相关文献资料, 对半日花荒漠群落的分布、群落特征及其分类进行了总结。结果表明: (1)半日花荒漠群落集中分布于黄河以东内蒙古西鄂尔多斯的阿尔巴斯山麓南北部、千里沟; 少量分布于黄河以西贺兰山北端内蒙古乌海市与阿拉善盟交界处及贺兰山最南端的内蒙古阿拉善盟与宁夏交界处明长城沿线的石质残丘。(2)根据样地调查, 半日花荒漠群落记录到种子植物58种, 隶属于17科39属, 其中灌木、半灌木18种, 多年生草本27种, 一年生草本植物13种; 水分生态类型中强旱生植物(15种)和旱生植物(29种)占绝对优势; 区系地理成分以中亚东部成分为主, 其次为古地中海成分和戈壁成分。(3)根据生活型和优势度, 半日花荒漠群落可分为半日花-草本荒漠群丛组、半日花-灌木-草本荒漠群丛组和半日花-半灌木荒漠群丛组, 进一步分为10个群丛。     

Structural analysis of loci involved in pSAM2 site-specific integration in Streptomyces

pSAM2 is an 11-kb plasmid integrated in the Streptomyces ambofaciens ATCC23877 and ATCC15154 genomes and found additionally as a free replicon in an uv derivative. After transfer into S. ambofaciens DSM40697 (devoid of pSAM2) or into Streptomyces lividans, specific integration of pSAM2 occurred very efficiently. A 58-bp sequence (att) present in both pSAM2 (attP) and S. ambofaciens strain DSM40697 (attB) attachment regions is found at the boundaries (attL and attR) of integrated pSAM2 in S. ambofaciens strain ATCC23877. The S. lividans chromosomal integration zone contained an imperfectly conserved att sequence (attB), and the integration event of pSAM2 was located within a 49-bp sequence of attB. Only one primary functional attB sequence was present in the S. lividans or S. ambofaciens DSM40697 total DNA. The integration zone of S. lividans hybridized with the integration zone of S. ambofaciens DSM40697. The two integration zones were homologous only to the right side of the att sequence. The conserved region contained an open reading frame (ORF A) with a stop codon located 99 bp from the attB sequence in both strains. S. ambofaciens DSM40697 contained DNA sequences related to pSAM2 on the left side of the att site. The att sequence was included in a region conserved in Streptomyces antibioticus, Streptomyces actuosus, Streptomyces bikiniensis, Streptomyces coelicolor, Streptomyces glaucescens, and Streptomyces parvulus. Site-specific integration of a pSAM2 derivative was characterized in another unrelated strain, Streptomyces griseofuscus. This strain contained an imperfectly conserved 58-bp attB sequence, and the integration event took place within a 45-bp sequence of attB. Site-specific integration of pSAM2 in three nonrelated Streptomyces strains suggests the wide host range of pSAM2 integration in Streptomyces.     

New and bioactive compounds from Streptomyces strains residing in the wood of Celastraceae

Wood from three different plants of the Celastraceae growing in their natural habitats in Brazil (Maytenus aquifolia Mart.) and South Africa [Putterlickia retrospinosa van Wyk and Mostert, P. verrucosa (E. Meyer ex Sonder) Szyszyl.] was established as a source of endophytic bacteria using a medium selective for actinomycetes. Two isolates were identified as Streptomyces setonii and S. sampsonii whereas two others were not assignable to any of the known Streptomyces species. They were preliminarily named Streptomyces Q21 and Streptomyces MaB-QuH-8. The latter strain produces a new chloropyrrol and chlorinated anthracyclinone. The chloropyrrol showed high activity against a series of multiresistent bacteria and mycobacteria.     

塔里木盆地荒漠盐碱生境土壤放线菌的初步研究

采用常规方法研究了新疆塔里木盆地荒漠盐碱生境土壤放线菌区系、放线菌的耐盐、碱性及对植物病原真菌的拮抗性。结果表明:土壤放线菌区系较单一,仅分离到链霉菌属和拟诺卡氏菌属,其中以链霉菌属为主(98.57%),链霉菌可分10个类群,以白孢类群为优势类群。土壤含盐量愈高,链霉菌组成愈简单。放线菌的最适生长盐浓度多集中在6%~8%,最适生长pH集中在7~8。24株供试放线菌中,有4株中度嗜盐放线菌对供试靶标菌有拮抗性,占供试菌的16.67%。     

Thermotolerant and thermophilic actinomycetes from soils of Mongolia desert steppe zone

In the actinomycete complexes of Mongolian desert soils, thermotolerant and thermophilic actinomycetes were found in high abundance, exceeding that of the mesophilic forms. Among the thermotolerant members of the order Actinomycetales, Streptomyces, Micromonospora, Actinomadura, and Streptosporangium species were most widespread in desert soils. Experiments with soil microcosms demonstrated that thermophilic actinomycetes in desert soils grew, developed, and formed mycelia of the length comparable to that of the mesophilic forms of actinomycetes. Molecular biological investigation of the samples of desert steppe soils by denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) revealed members of the phylum Actinobacteria. FISH analysis revealed that the biomass of the metabolically active mycelial actinobacteria in the prokaryotic community of Mongolian desert soils exceeded that of the unicellular Actinobacteria.     

Haloalkaliphilic actinomycetes in soils of Mongolian desert steppes

The abundance of actinomycetes isolated from the soils of Mongolian desert steppes varies from several thousand to hundreds of thousands of CFU/g soil, depending on soil type and isolation medium. Eight actinomycete genera have been found in these soils: Streptomyces, Micromonospora, Saccharopolyspora, Actinomadura, Microtetraspora, Thermomonospora, Nocardia, and Dactylosporangium. The streptomycete complexes of brown desert-steppe and gray-brown desert alkaline soils include halophilic, alkaliphilic, and haloalkaliphilic species that grow most successfully on the media with a salt concentration of 5% and pH 8–9.     

海绵中石油降解微生物的分离筛选及降解特性研究

从大连湾原油污染海域生长的海绵中分离筛选到一株原油降解菌OA58,根据其生长形态、培养特征、16S rRNA序列相似性比对分析和生化指标检测,初步鉴定为脱叶链霉菌（Streptomyces exfoliatus）。同时,考察了该链霉菌对原油的降解效果,OA58能以原油为唯一碳源生长,在人工海水培养基中,14 d内对原油（初始浓度为1 g/L）的平均降解率为83%,是一株具有开发潜力的原油降解放线菌。