山东链霉菌产抗真菌物质的理化性质的初步研究

从土壤中筛选得到1株产广谱抗真菌物质山东链霉菌(Streptomyces shandongensissp．nov)，该菌代谢产物对多种植物病原真菌有很强的抗菌作用．研究了温度及pH变化、UV照射对该菌发酵液中抗菌物质的稳定性的影响；并利用pH纸层析等多种层析技术研究了该抗菌物质的水溶性、离子特性等一些理化性质，为这一农用抗生素的进一步纯化和结构测定提供依据．     

链霉菌S1的抑菌活性及其对植物病害的防治

摘要： 为了探明链霉菌S1的抑菌活性及其对植物病害的防控作用,通过抑菌圈法研究了链霉菌S1对不同病原菌的抑制作用并分析了菌株S1是否合成几丁质酶和葡聚糖酶,筛选了菌株S1的最佳发酵培养基、发酵时间和最佳接种量,进一步优化发酵培养条件。通过温室防效实验,研究了链霉菌S1发酵液对桃核腐病和番茄根结线虫的防治作用。结果表明：链霉菌S1对多种病原菌有较好的抑菌作用,其中对桃褐腐病原真菌（Monilinia fructicola）和平菇褐斑病原细菌（Pseudomonas tolaasii）的抑制效果最佳。菌株S1能够合成几丁质酶,不能合成葡聚糖酶。链霉菌S1的最佳发酵培养基为G117,最佳发酵时间为3 d,最佳接种量为8%。链霉菌S1的发酵上清液和发酵液对桃核腐病具有显著的防治作用,防效可到达80.66%。发酵代谢产物对番茄根结线虫的杀线活性最高可达90%,发酵原液对番茄根结线虫的防治效果最高到达71.02%。可见链霉菌S1具有较好的防治作用,为植物病害生物防治提供了优良的菌种资源。     

新型2-甲基-3-呋喃甲酰胺类化合物的设计、合成及抑菌活性研究

为寻找高活性抑菌化合物,20种以杀菌剂甲呋酰胺为结构基础的新型2-甲基-3-呋喃甲酰胺类化合物经过设计并合成,它们的结构已通过氢核磁确定.接着,选取5种常见且具有代表性的植物病原真菌(水稻纹枯病菌、油菜菌核病菌、马铃薯晚疫病菌、番茄绵腐病菌、苹果轮纹病菌)作为供试菌种,采用生长速率法对所合成的目标化合物进行了抑菌活性初步筛选.结果表明:在浓度为20mg/L时,化合物1e,1f,2a,2b和2f对水稻纹枯病菌的校正抑菌率分别为88.6%、74.5%、78.5%、78.7%和73.1%,优于阳性对照甲呋酰胺(70.5%).进一步对5种化合物抑制水稻纹枯病菌有效中浓度(EC_(50))的测定,发现化合物1e的EC_(50)值为2.824mg/L,优于阳性对照杀菌剂甲呋酰胺(EC_(50)=7.691mg/L).表明化合物1e对水稻纹枯病菌抑菌活性最强,可作为先导化合物进一步结构优化.     

木姜子乙醇提取物抑菌活性研究

采用生长速率法在室内测定了木姜子乙醇提取物对燕麦镰刀菌、烟草赤星病菌、石榴枯萎病菌3种植物病原菌的抑制活性.结果表明,植物提取物对3种植物病原菌都有显著的抑制作用,木姜子作为植物源杀菌剂值得进一步研究.     

Antifungal proteins: targets,mechanisms and prospective applications

All organisms have evolved several defence systems in order to protect themselves against bacteria, fungi and viruses. Higher organisms have developed a complex network of humoral and cellular responses, called adaptive immunity. A second defence system, innate immunity, was discovered in the early 1980s, consisting of small cationic peptides with a broad antimicrobial spectrum. These proteins act immediately at sites of infection or inflammation. The production of proteins with antimicrobial activity was not limited to higher organisms but was also found in insects, plants and microorganisms. During the last 2decades a broad range of proteins with very different structural features have been isolated and characterised from differing organisms ranging from bacteria to human beings. Over 500cationic membrane-acting proteins with antimicrobial and antifungal activities have been identified to date. Apart from these proteins, a very large number of antifungal proteins active on the fungal cell wall, on enzymes of the cell wall synthesis machinery, the plasma membrane and on intracellular targets have been characterised.Received 17 June 2003; received after revision 4 August 2003; accepted 18 August 2003     

海洋放线菌S—216菌株鉴定及其抗真菌抗生素合成条件研究

海洋放线菌Ｓ－２１６系从厦门杏林湾海泥中分离获得,根据该菌株在高氏合成一号培养基上的生长特征,列入链霉菌属（Ｓｔｒｅｐｔｏｍｙｃｅｓ）黄色类群;其形态、培养特征、生理生化特性与微白黄链霉菌（Ｓ．ａｌｂｉｄｏｆｌａｖｕｓ）相似,但又有明显区别;该菌全细胞水解液中含ｌ－二氨基庚二酸、甘氮酸、丙氨酸、无门冬氨酸．菌体含有特征性半乳糖、葡萄糖和核糖,ＤＮＡ中的Ｇ＋Ｃ克分子含量为７５．２ｍｏｌ．该菌株能产生专一性较强的抗真菌抗生素,对白色念珠菌（Ｃａｎｄｉｄａａｌｂｉｃａｎｓ）、新型隐球酵母（Ｃｒｙｐ－ｔｏｃｏｃｃｕｓｎｅｏｆｏｒｍａｎｓ）、烟曲霉（Ａｓｐｅｒｇｉｌｕｓｆｕｍｉｇａｔｕｓ）等十多种真菌都具有不同程度的抑制作用,但对细菌无效;能产生几丁质酶．故认为是微白黄链霉菌一新变种,定名为微白黄链霉菌海洋变种（Ｓ．ａｌｂｉｂｏｆｌａｖｕｓＶａｒ．ｍａｒｉｎａ,）在发酵培养基Ａ．接种量１０％,发酵时间９６ｈ,为合成抗生素最佳条件．     

一株生防烟管菌几丁质酶表达及抗真菌活性

为了探究烟管菌BK-1的生物防治潜力,本研究测试了一株具有生防菌活性的烟管菌BK-1的抗病效果,并使用RT-qPCR分析了该菌株的8个细胞壁裂解酶基因在与不同病原真菌对峙培养中的表达水平,结果表明,在应对链格孢、茄链格孢、尖孢镰刀菌和灰葡萄孢这4种病原真菌时,几丁质酶基因BaCHIB表达上调了27.3至50.3倍,远高于其他7个基因.BaCHIB属于糖苷水解酶18家族(GH 18),并具有Chic_BD结构域,属于B类几丁质酶(CHIB).结合基因表达谱分析,该基因诱导表达上调情况的出现与抗病效果的出现高度同步.外源表达蛋白BaCHIB显示出较高的几丁质酶活性,且表现出对多种植物病原真菌,包括链格孢,链格孢和灰葡萄孢显著的抗真菌活性,显示其对部分病原真菌具有拮抗能力.     

拮抗菌246-1 活性物质合成条件优化及其抑菌作用的研究

分离自青海湖周边土壤的菌株246-1平板对峙实验显示了对黄瓜枯萎病菌(Fusarium oxysporum f. sp. cucumerinum)的抑制作用,通过16S rDNA鉴定其为多粘类芽孢杆菌(Paenibacillus polymyxa)。本实验通过筛选fusaricidins提取纯化和检测方法,确定发酵液酸化是fusaricidins提取纯化的一个重要步骤,同时确定乙腈/水/TFA检测体系为fusaricidins HPLC检测流动相。采用抑菌圈实验筛选出最适合多粘类芽孢杆菌246-1产fusaricidins的培养基,用单因素实验方法对其培养条件进行优化。结果表明,246-1菌株的培养基配方为可溶性淀粉17.5 g.L_-1,酵母浸出粉4 g.L_-1,蛋白胨25 g.L_-1,NaCl 1.25 g.L_-1,Na₂HPO₄ 0.5 g.L_-1,CaCl₂ 1g.L_-1,蔗糖15 g.L_-1,最佳培养时间 48 h, 初始 pH 7.0, 培养温度 30 ℃。进一步分析了多粘类芽孢杆菌246-1对黄瓜幼苗的促生作用,在黄瓜幼苗根际的定殖能力和对黄瓜枯萎病的防效作用。盆栽试验结果表明,菌株246-1的发酵上清液对黄瓜枯萎病菌表现出很强的抑制作用,同时该菌株在黄瓜幼苗根际具有很好的定殖能力,表现了对黄瓜幼苗的显著促生效果。     

The Penicillium chrysogenum antifungal protein PAF, a promising tool for the development of new antifungal therapies and fungal cell biology studies

In recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due to their potential to prevent and combat microbial infections in all areas of life. A detailed knowledge about the function of such proteins is the most important requirement to consider them for future application. Our research in recent years has been focused on the low molecular weight, cysteine-rich and cationic antifungal protein PAF from Penicillium chrysogenum, which inhibits the growth of opportunistic zoo-pathogens including Aspergillus fumigatus, numerous plant-pathogenic fungi and the model organism Aspergillus nidulans. So far, the experimental results indicate that PAF elicits hyperpolarization of the plasma membrane and the activation of ion channels, followed by an increase in reactive oxygen species in the cell and the induction of an apoptosis-like phenotype. Detailed knowledge about the molecular mechanism of action of antifungal proteins such as PAF contributes to the development of new antimicrobial strategies that are urgently needed. Received 09 August 2007; received after revision 17 September 2007; accepted 19 September 2007     

苔藓植物的主要次生代谢产物与有害生物防治

苔类的主要次生代谢产物为倍半萜、联苄和二联苄,藓类则以黄酮为主。苔类植物中的抗菌、抗真菌活性成分有异戊烯基联苄、地钱素A、网地藻烷型二萜及其衍生物、酚基倍半萜、a-santonin、核子木素A、B及其衍生物、三裂鞭台醇、Dicrnenone A、DicranenoneB1等。许多苔类中富集的半月苔认为可能完全足以抵御真菌的感染。藓类中常见的双黄酮和聚酚基化合物能够抵御真菌感染和昆虫的摄食。泥炭藓醇是导致泥炭藓和灰藓类分解较慢的因素之一,苯甲酸苄酯类对昆虫和螨类是致命的,草酸对植食性昆虫有排斥作用,藓类枝条内的protocatechiuc和五倍子酸对刺激蛾科昆虫有拒食作用,其它包括绿片酮pinguisone、囊绒苔醛、桉叶油内酯、大根香叶烷、倍半萜内酯、补身基烷内酯、Gymnocolin。Albicanol aceate对金鱼有明显的拒食作用,一系列天然的补身烷及相关的合成化合物被证明对蚜虫有拒食作用。Polygodial被认为是作为昆虫拒食剂最有效的天然产物之一,还能够抑制鱼类的摄食。浮苔素A、浮苔素B、半月苔酸、半月苔甲酯、和5－羟基半月苔酸有灭螺活性。绝大多数苔藓的粗提物,特别是含有芳香性化合物的,表现出抑制发芽、根伸长、及胚芽鞘的生长的活性。半月苔酸、isobidyclogermacrenal、指叶苔醛、指叶苔醇及其羟基衍生物、硬指叶苔醇、一些2,3－断香橙烷型倍半萜半缩醛、甲氧基plagiochilines、（一）－polygodial、折瓣苔烷型二萜化合物、和3a,4a-epoxy-5a-acetoxy-18-hydroxysphenolobal13E,16E－diene对植物生长有抑制作用。