短小芽孢杆菌溶藻效应研究

随着全球水体富营养化的加剧,有害藻类水华的暴发日趋频繁,其造成的环境和经济问题日益引起人们的重视,寻求有效的水华和赤潮防治途径势在必行。溶藻细菌作为水生生态系统中生物种群结构和功能的重要组成部分,对维持浮游植物生物量平衡具有非常重要的作用。不少研究认为水华和赤潮的突然消亡可能与溶藻细菌的感染有关。有些溶藻细菌能够分泌细胞外物质,对宿     

溶藻细菌

利用溶藻细菌防治水华和赤潮,作为富营养化水体藻类生物防治的方法已经受到广泛关注.多项研究表明,许多溶藻细菌能分泌胞外活性物质,对宿主藻类的生长起抑制作用.因此,分离筛选环保、高效、专一的溶藻活性代谢产物,最终开发安全、高效的生物杀藻剂已经日渐成为治理藻类水华和赤潮问题的方法之一.近年来,国内外相关人员和机构对溶藻细菌的溶藻机理以及溶藻活性物质的分离、提纯和鉴定进行了较为深入的基础性研究.     

溶藻细菌的生态学作用及其生物量检测方法

有害藻类水华已成为当今世界水体普遍存在的环境问题,溶藻细菌作为水华和赤潮防治的可能生物,引起了众多科研人员的关注。介绍了溶藻细菌的研究概况,重点对溶藻细菌的生态学作用及其生物量的检测方法进行了综述。     

溶藻微生物净化富营养化水体的作用

湖泊富营养化导致的水华藻类频繁暴发已成为当今世界性的环境问题,溶藻微生物作为生物法防治有害藻类水华具有广泛的研究前景,通过查阅文献对微生物控制有害藻类水华进行概述,并探讨进一步的研究趋势和应用前景,以期对微生物溶藻方面的研究及开发应用有一定的参考价值。     

溶藻细菌杀藻物质的研究进展*

溶藻细菌作为防治有害藻类水华的一种可能微生物,已引起了众多科研人员的关注。大多数溶藻细菌分泌的生物活性杀藻物质对宿主藻类具有强烈的杀灭作用。首先讨论了细菌活性杀藻物质的生态作用,重点阐述了目前已经报道的细菌杀藻物质的种类及其提取和分离方法,最后对细菌杀藻物质的进一步研究提出几点看法。     

溶藻微生物的研究进展

溶藻微生物在防治有害藻类水华中的作用和潜力,已受到学者的广泛关注.综述溶藻微生物(主要是溶藻细菌和噬藻体)的溶藻作用机制,量效关系及分子生物学.阐述溶藻微生物对蓝藻水华治理存在的问题,并对溶藻微生物作为潜在的控藻因子进行展望.     

滇池中溶藻细菌的分离鉴定及其溶藻效应

【背景】藻类水华或赤潮在世界范围内频发,带来各种危害,亟需找到有效途径控制水华或赤潮。溶藻细菌具有杀死藻类控制藻类生物量的能力,可以作为防治水华和赤潮的有效工具。【目的】分离并鉴定滇池中的铜绿微囊藻(Microcystisaeruginosa)及其溶藻细菌,对溶藻菌作用于铜绿微囊藻的溶藻效应进行研究,初步了解其溶藻特性与溶藻机制。【方法】采用LB平板稀释涂布,再经多次划线分离纯化细菌,测定16SrRNA基因序列以鉴定细菌种类;采用毛细管分离的方法分离铜绿微囊藻,并测定其cpcBA基因序列以鉴定蓝藻种类;采用热乙醇法提取叶绿素a,从而计算溶藻效率;基于过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)和丙二醛(MDA)探究藻细胞在溶藻菌处理下的抗氧化系统响应。【结果】共分离获得11株微囊藻和17株针对铜绿微囊藻的高效溶藻菌。选取其中一株生长速度最快的铜绿微囊藻DCM4和一株溶藻效果最好的溶藻菌Sp37 (Bacillus siamensis)进行后续研究。Sp37对DCM4的4 d溶藻率达到92.4%±1.5%,且对微囊藻属的水华微囊藻(M. flos-aquae)和惠氏微囊藻(M.wesenbergii)均有溶藻效果,而对绿藻没有溶藻效果。Sp37的原菌液和无菌滤液对DCM4的4d溶藻率分别为86.8%±4.3%和81.1%±2.2%,两者没有显著差异(P0.05)。Sp37菌体对DCM4的溶藻率为25.4%±7.3%。Sp37无菌滤液经不同温度和pH处理之后的溶藻率与未经处理的无菌滤液的溶藻率无明显差异。Sp37无菌滤液处理藻细胞会使藻细胞的CAT、GSH和MDA含量发生变化。【结论】菌株Sp37对铜绿微囊藻DCM4具有高效的溶藻作用,而且对微囊藻属具有一定的溶藻特异性。Sp37是通过分泌胞外物质间接溶藻,且溶藻物质具有热稳定性和酸碱稳定性。Sp37无菌滤液处理藻细胞会触发藻细胞抗氧化系统,并且会损伤藻细胞膜。Sp37无菌滤液很可能是通过对藻细胞造成氧化胁迫,最终导致藻细胞死亡的。     

溶藻细菌对固氮藻氮代谢的影响

随着水体富营养化的加剧,有害藻类水华和赤潮的爆发日趋频繁,导致水质的恶化,水体资源丧失其功能和价值。修复藻型富营养化水体生态系统可以从控制藻类繁殖和调整藻类群落结构方面着手,使整个水生     

溶藻细菌及溶藻化合物研究进展

生物治理有害藻华因其具有无毒、高效、专一性强等特点,已成为富营养化水体治理的研究热点。本文从溶藻细菌种类、溶藻机制和溶藻化合物等三个方面对近十年已报道的溶藻细菌及其化合物的研究进展进行了归纳和总结,并探讨了溶藻细菌工业化应用研究中遇到的问题及其原因,据此提出了建议以期促进溶藻细菌的工业化应用研究。     

一株中肋骨条藻特异溶藻菌的分离鉴定及溶藻特性

【背景】赤潮频发引起严重的海洋生态学问题,不仅直接影响到海洋生态系统稳定、海洋生物资源可持续利用和水产养殖业等海洋产业的健康发展,而且对人类健康也构成了严重威胁。高效的溶藻细菌是生物法防控赤潮的有效工具之一。【目的】分离得到对中肋骨条藻具有高效溶藻效果的溶藻细菌,并对其进行分子鉴定,研究该菌株的溶藻机理以及溶藻菌所分泌溶藻物质的特性。【方法】采用2216E平板稀释涂布法分离纯化细菌,测定16S rRNA基因序列以鉴定细菌种类,利用显微镜计数溶藻菌处理后的目标藻种计算溶藻率,通过扫描电镜观察溶藻菌对中肋骨条藻的溶藻过程,利用常规生理生化方法研究溶藻菌溶藻物质的特征,并通过透析袋截留法研究溶藻物质分子量大小。【结果】分离得到一株中肋骨条藻高效溶藻菌FDHY-CJ,该菌株属于交替单胞菌属(Alteromonas sp. FDHY-CJ)。该菌株72 h处理赤潮藻结果显示,对中肋骨条藻溶藻率为95.45%,对于其他常见赤潮藻溶藻率低于40%。溶藻菌FDHY-CJ通过胞外分泌物溶藻;溶藻物质的溶藻特性不受反复冻融的影响,但对酸碱性及温度较为敏感;扫描电镜观察结果显示该溶藻菌的溶藻物质直接溶解中肋骨条藻的细胞壁,致使硅质壳打开、内容物流出,达到溶藻的效果;溶藻活性物质具有被乙醇和乙酸乙酯沉淀的特性。【结论】溶藻菌FDHY-CJ对中肋骨条藻具有特异溶藻作用,对其他常见赤潮溶藻效果不明显;该细菌溶藻方式为通过分泌物间接溶藻,溶藻物质属于蛋白类,大小在3.5?10 kD之间。     

有害微藻抑藻细菌多样性及抑藻机制研究进展

有害藻暴发能够破坏水生生态系统,对水环境、人类健康及各国经济构成严重威胁。寻找能够有效防治有害藻华或赤潮的方法是现阶段水生生态保护与修复领域的重要研究内容之一。其中,微生物因其分布广、种类多和易繁殖等特点,在有害藻华或赤潮防治方面表现出巨大潜力,正逐渐得到广泛关注。本文从抑藻细菌分布、物种多样性及抑藻机制(抑藻方式、细胞形态、光合作用和氧化损伤)等角度对当前有害微藻抑藻细菌研究进展进行梳理总结,为微生物控藻提供理论参考。     

Dynamics of cyanophage-like particles and algicidal bacteria causing Microcystis aeruginosa mortality

The dynamics of cyanophage-like particles and algicidal bacteria that infect the bloom-forming cyanobacterium Microcystis aeruginosa was followed in a hyper-eutrophic pond from September 1998 to August 1999. The densities of M. aeruginosa ranged between 4.0 × 10⁵ and 1.9 × 10⁷ cells ml⁻¹, whereas those of algicidal bacteria were between 4.0 and 5.1 × 10² plaque-forming units (PFU) ml⁻¹ and those of cyanophage-like particles were between <5.0 × 10² and 7.1 × 10³ PFU ml⁻¹. A significant relationship was found between the densities of algicidal bacteria and M. aeruginosa (r = 0.81, n = 69, P < 0.001), suggesting that the dynamics of the algicidal bacteria may regulate the abundance of M. aeruginosa. Occasional peaks of density of cyanophage-like particles were detected in October, June, and August, when sharp declines in M. aeruginosa cell densities were also observed. The densities of cyanophage-like particles became undetectable when the abundance of M. aeruginosa was low, suggesting the density-dependent infection of M. aeruginosa by cyanophage-like particles. Thus, we suggest that infections of both algicidal bacteria and cyanophage-like particles are important biological agents that decompose blooms of M. aeruginosa in freshwater environments. Received: August 31, 2000 / Accepted: December 6, 2000     

水华杀藻微生物的分离与分子生物学鉴定

正除藻方法一般分为工程物理方法、化学药剂法和生物方法三大类。作为庞大的富营养化湖泊的藻类控制技术,利用工程物理方法和化学药剂法显然是行不通的,对环境友好的生物控藻技术受到越来越多的关注,国内外许多富营养化湖泊水华的控藻技术的研究热点转向生物控藻技术。在利用生物控藻上,目前主要有三个方面,一是以鱼类控制藻类的生长;二是以水生高等植物控制水体富营养盐及藻类; 三是以微生物来控制藻类的生长。其中由于微生物易于繁殖的特点,使得微生物控藻是生物控藻里最有前途的一种控藻方式。这些杀藻微生物主要包括细菌(溶藻细菌)、病毒 (噬藻体)、原生动物、真菌和放线菌等五类。国内外对杀藻微生物的分离和鉴定有一些报道,但都不够系统和全面, 本文以本实验室的工作为基础,较全面、系统地介绍前三类水华杀藻微生物的分离与纯化及其分子生物学鉴定方法。       

Characterization of an algicidal bacterium Brevundimonas J4 and chemical defense of Synechococcus sp. BN60 against bacterium J4

As part of efforts to enhance the strategies explored to eliminate the adverse impacts of cyanobacterial blooms, we isolated an algicidal bacterium, J4, from Lake Taihu. Analysis of 16S rDNA sequence revealed that strain J4 belonged to the genus Brevundimonas. Bacterium J4 exhibited algicidal activity mainly through excretion of extracellular algicidal compounds that were further extracted with methanol and purified by silica gel chromatography and high performance liquid chromatography (HPLC). The compounds showed thermal stability, strong polarity and water solubility in J4 cultures. Study on the algicidal activity of J4 against two dominant cyanobacterial bloom-forming species in Lake Taihu showed that J4 exhibited lower algicidal rate against Synechococcus sp. BN60 (48.6%, t = 6 days) than against Microcystis aeruginosa 9110 (91.8%, t = 6 days). Additionally, rapid reduction in cell density of J4 was observed in co-cultures of Synechococcus sp. BN60 and bacterium J4 but not observed in co-cultures of M. aeruginosa 9110 and bacterium J4 during algicidal process, which was the main reason why the algicidal rate of J4 against BN60 was lower than against 9110. The reduction in cell density of J4 resulted from inducible production of antimicrobial-like compound secreted by Synechococcus sp. BN60 in co-cultures of Synechococcus sp. BN60 and bacterium J4, which reflected a kind of chemical defense from cyanobacteria (BN60) against algicidal bacteria (J4). However, M. aeruginosa 9110 had no chemical defense against J4, suggesting that whether cyanobacterial chemical defense occurs or not between cyanobacteria and algicidal bacteria depends on specific cyanobacteria–algicidal bacteria pairs. These results show that not only one-sided algicidal effect but also two-sided reciprocal inhibition interactions exist between algicidal bacteria and cyanobacteria, indicating the complexity of cyanobacteria–algicidal bacteria interactions in Lake Taihu and the need to take the cyanobacterial defensive responses into consideration when assessing potential use of algicidal bacteria.     

抑藻菌株Bacillus sp. hsn03分离鉴定及其对铜绿微囊藻的抑制效果与特征

【背景】蓝藻常形成水华,严重破坏水生环境及威胁水生生物。微生物能够专一性地抑制蓝藻的生长,从而可以被用于蓝藻水华的控制。【目的】分离筛选一株对有害水华藻——铜绿微囊藻(Microcystisaeruginosa)7806有高效抑藻能力的菌株,对其进行生理生化和分子鉴定,并研究其抑藻效果与特征。【方法】通过API试剂条确定其生理生化特征,对细菌的16SrRNA基因进行测序并构建系统进化树,通过探究细菌菌体、上清、发酵液的抑藻效果确定该菌的抑藻方式,通过测定不同温度、pH、蛋白酶K、有机溶剂萃取和透析条件下的抑藻效果及傅里叶红外光谱来确定胞外抑藻物质的性质。【结果】菌株hsn03与芽孢杆菌属(Bacillus sp.)的Bacillus sonorensis NBRC101234有最高相似性,达99.59%;通过分泌胞外抑藻物质对铜绿微囊藻生长表现出抑制效果,且最佳抑藻添加量为7.0%(体积比);胞外抑藻物质为一类分子量大于500 Da且小于1 kD,耐高温,耐酸碱,含有叁键和累积双键,非蛋白、多糖类的小分子物质。【结论】抑藻菌株的挖掘与鉴定对于丰富有害藻华藻的抑藻菌质资源有非常大的促进作用,通过对抑藻方式、效果和特征的研究为进一步将抑藻菌应用于铜绿微囊藻的治理奠定基础。     

Novel algicidal evidence of a bacterium Bacillus sp. LP-10 killing Phaeocystis globosa,a harmful algal bloom causing species

While searching for effective bio-agents to control harmful algal blooms (HABs), the bacterial strain LP-10, which has strong algicidal activity against Phaeocystis globosa (Prymnesiophyceae), was isolated from surface seawater samples taken from the East China Sea. 16S rDNA sequence analysis and morphological characteristics revealed the strain LP-10 belonged to the genus Bacillus. The lytic effect of Bacillus sp. LP-10 against P. globosa was both concentration- and time-dependent. Algicidal activities of different growth stages of the bacterial culture varied significantly. The lytic effect of different parts of the bacterial cultures indicated that the algal cells were lysed by algicidal active compounds in the cell-free filtrate. Analysis of the properties of the active compounds showed that they had a molecular weight of less than 1000 Da and that the active compounds were stable between −80 and 121 °C. The algicidal range assay indicated that five other algal species were also suppressed by strain LP-10, including: Alexandrium catenella, A. tamarense, A. minutum, Prorocentrum micans and Asterionella japonica. Our results suggested that the algicidal bacterium Bacillus sp. LP-10 could be a potential bio-agent to control the blooms of harmful algal species.