温郁金内生真菌Chaetomium globosum L18对植物病原菌的抑菌谱及拮抗机理

通过体外培养法,研究了药用植物温郁金内生真菌Chaetomium globosum L18对几种常见的植物病原菌的抑菌谱及其拮抗机理。结果表明,Chaetomium globosum L18对多种植物病原真菌和细菌均有不同程度的抑制作用,具有较广的抑菌谱,但对不同植物病原菌的抑制作用具有显著性差异(P<0.05),抑制率最高可达到92.9%;抑菌机制结果显示,竞争作用和重寄生作用是其主要的拮抗机制之一;发酵产物抑制作用测定发现,内生真菌Chaetomium globosum L18能够分泌产生抗菌物质抑制病原菌菌丝的生长和孢子萌发,可引起病原菌菌丝菌丝膨大成串珠状,分枝增多,分枝顶端膨胀后细胞壁破裂,原生质外溢,产生溶菌作用;使分生孢子萌发畸形,萌发率降低。     

鹅膏菌抑真菌活性及其活性物质的提取工艺优化(英文)

通过鹅膏菌抑菌活性物质对杨树烂皮病病原菌金黄壳囊孢菌的菌丝生长及其孢子抑制效果的研究,分析鹅膏菌的抗真菌活性。将培养15 d的鹅膏菌液体发酵物分成培养液和菌丝体两部分,然后分别将培养液、菌丝体提取物和发酵液本身对金黄壳囊孢菌菌丝生长和孢子萌发抑制效果进行检测。结果表明:培养液对金黄壳囊孢菌菌丝生长的抑制率最高,为68.90%;三者对孢子萌发都有明显的抑制效果,即在处理后10 d孢子都没有萌发。菌丝体在超声波、加热和浸泡的条件下,利用乙醇,丙酮、乙酸乙酯和正丁醇进行提取,其提取物用于病原菌的抑制效果检测,结果表明:用乙醇和丙酮提取时,超声波、浸泡及加热处理,对金黄壳囊孢菌的抑制效果都与对照有显著差异(a=0.01),而正丁醇的提取物的抑制效果较差,与对照没有显著差异。通过不同提取物对金黄壳囊孢菌菌丝生长和孢子萌发的抑制效果进行分析,并对抑菌活性物质提取工艺进行筛选,得到抑菌活性物质提取的最佳方法为摇床培养,乙醇是最适提取溶剂,处理方式(超声波、浸泡或者加热)相互间差异不显著。     

一株链霉菌21-1的分离鉴定及其对禾谷镰刀菌的抑菌活性

【背景】由禾谷镰刀菌（Fusarium graminearum）引起的小麦赤霉病严重威胁我国的小麦生产。【目的】筛选对禾谷镰刀菌具有拮抗能力的链霉菌菌株,为生防菌剂开发提供理论基础。【方法】利用平板对峙法筛选对禾谷镰刀菌具有拮抗能力的链霉菌;通过形态特征、生理生化特征和16S rRNA基因序列分析对其进行鉴定;通过病原菌菌丝生长、孢子产生及萌发抑制试验分析其发酵液的抑菌活性;利用人工接种试验测定该菌株发酵液的防病效果。【结果】筛选到一株对禾谷镰刀菌具有较强拮抗活性的链霉菌21-1,抑菌率为59.5%。依据形态特征、生理生化特性和16S rRNA基因序列分析,将该菌株鉴定为黄三素链霉菌（Streptomyces flavotricini）。菌株21-1发酵液能够抑制禾谷镰刀菌的菌丝生长、孢子产生及萌发过程,而且可以降低禾谷镰刀菌菌丝中可溶性蛋白质的含量,并增加丙二醛的含量。菌株21-1可以产生蛋白酶及纤维素酶。菌株21-1菌液10倍稀释液对小麦赤霉病的防效最佳,为70.1%。此外,菌株21-1发酵液对其他8种植物病原菌均有较好的抑制作用。【结论】菌株21-1对禾谷镰刀菌有较好的抑菌活性,具有潜在的应用价值。     

库尔勒香梨黑斑病菌拮抗菌筛选及其抑菌机理

【背景】由互隔交链孢(Alternaria alternata)引起的黑斑病是库尔勒香梨采后贮期的主要病害之一,严重影响果实品质,造成巨大的经济损失。【目的】筛选对梨黑斑病菌具有高拮抗活性的菌株并探究其可能的抑菌机制,为香梨采后保鲜提供理论依据。【方法】从库尔勒香梨园健康植株根际采集土壤样品,采用稀释涂布法分离细菌并进行纯化,通过平板对峙法和琼脂打孔法筛选对梨黑斑病菌具有显著拮抗作用的菌株,结合形态学观察和16S rRNA基因序列分析进行初步鉴定;通过平板对峙法对拮抗菌抑菌谱进行测定;采用特异性平板定性检测拮抗菌产酶活性,采用3,5-二硝基水杨酸比色法法及福林-酚法定量酶活;通过孢子萌发抑制试验和扫描电镜观察,测定拮抗菌对梨黑斑病菌的拮抗作用。【结果】筛选得到2株对梨黑斑病菌有较强抑制活性的菌株JE53和JE56,经分析鉴定为多粘类芽孢杆菌(Paenibacillus polymyxa)及枯草芽孢杆菌(Bacillus subtilis),其发酵上清液对梨黑斑病菌的抑菌圈直径分别为22.49 mm和22.40 mm。抑菌谱测定结果表明,菌株JE53和JE56对马铃薯黑痣病菌等9种植物病原菌均有不同程度的抑制作用。胞外酶测定结果显示这2株菌可产生4种胞外酶;其发酵上清液能够显著抑制病原菌孢子萌发,抑制率分别为70.30%和88.87%;扫描电镜发现这2株菌可导致病原菌菌丝表面粗糙、扭曲变形。【结论】JE53和JE56对梨黑斑病菌有较好的抑制效果,具有进一步开发和应用的潜力。     

丁布对小麦赤霉病菌和玉米小斑病菌的抑制作用

采用菌丝生长速率法和孢子萌发试验法检测了抗菌化合物丁布对小麦赤霉病菌和玉米小斑病菌的抑菌作用。结果表明,丁布在PDA培养基中浓度为0.2-1.0 mg/ml时对两种供试病菌的菌丝生长无抑制作用;丁布浓度为0.4-1.0 mg/ml时对两种供试病菌孢子悬浮液中孢子的萌发具有显著抑制作用;1.0 mg/ml丁布药液中培育15h的小麦赤霉病菌和培育5h的玉米小斑病菌的孢子萌发抑制率分别达到100%和83.6%。     

357细菌及其拮抗物质对植物病原真菌的抑制*

Bacilluscereus 357细菌及其分泌的拮抗物质对水稻纹枯病菌和草莓灰霉病菌有较好的拮抗作用。它们可抑制或杀死这两种病原菌的菌丝 ,可使菌丝枯萎和产生畸形。 357细菌分泌的拮抗物质还可抑制草莓灰霉病菌孢子的萌发和孢子的形成。该拮抗物质对热、酸、碱等有较高的稳定性。     

解淀粉芽孢杆菌BA-26抗菌物质分离及对灰葡萄孢抑菌作用研究

分析解淀粉芽孢杆菌(Bacillus amyloliquefaciens)BA-26发酵液中抑菌物质存在情况,明确活性物质的抑菌效果,初步探索其抗植物病原真菌的作用机制。通过硫酸铵沉淀、大孔树脂吸附及反相高效液相色谱法(RP-HPLC),从菌株BA-26的发酵液中分离纯化抗菌物质;采用平板对峙法检测抗菌物质抑菌活性;用二倍稀释法测定各活性组分的最小抑菌浓度(MIC),并研究其对菌丝和孢子萌发的影响。从菌株BA-26发酵液中获得抗菌粗提物抑菌谱广,对立枯丝核菌等多种植物病原真菌有强抑制作用;分离纯化得到11个具有抑制真菌作用的活性组分;其中A6-19和A6-20组分对灰葡萄孢(Botrytis cinerea)抑菌活性最强,最小抑菌浓度为7.81μg/mL;菌株BA-26产生的抗真菌活性物质能使灰葡萄孢菌丝生长受阻、膨大变粗、细胞膜破坏并能抑制其孢子萌发。明确了解淀粉芽孢杆菌BA-26菌株产抗菌物质情况,初步探究其抑菌作用机制,为抗菌物质在防治病原真菌等方面的应用奠定基础。     

炭团菌提取物对樟子松枯梢病菌的抑菌活性及稳定性研究

采用水提和酯提2种方式提取炭团菌液体培养菌液中高效抑制樟子松枯梢病菌活性物质。采用生长速率法测定提取物对病原菌菌丝生长的抑制率,采用悬滴法测定其对病原菌孢子萌发的抑制率。炭团菌液体培养菌液乙酸乙酯提取物稳定性试验选用紫外线、温度、pH、氧化剂与还原剂以及贮存时间5个因子。结果表明:炭团菌液体培养菌液的5种提取物对樟子松枯梢病菌均有一定的抑菌活性,乙酸乙酯提取物对病原菌菌丝生长的抑制率最高,达到73.20%;乙酸乙酯提取物、超声波提取物、正丁醇提取物对病原菌孢子萌发抑制率均超过90%。乙酸乙酯提取物对自然环境下的紫外线、温度具有很高的稳定性,并且有一定的抗氧化还原能力和良好的耐热性,长期贮存不影响其抑菌活性,具有很高的开发价值和很好的应用前景。     

357细菌及其拮抗物质对植物病原真菌的抑制

Bacillus cereus357细菌及其分泌的拮抗物质对水稻纹枯病菌和草莓灰霉病菌有较好的拮抗作用。它们可抑制或杀死这两种病原菌的菌丝,可使菌丝枯萎和产生畸形。357细菌分泌的拮抗物质还可抑制草莓灰霉病菌孢子的萌发和孢子的形成。该拮抗物质对热、酸、碱等有较高的稳定性。     

一株新的拮抗细菌SL19及其抑菌活性物质

生防菌SL19对多种植物病原菌有抑菌活性。通过形态观察、生理生化实验和基于16S rDNA同源性序列分析构建系统发育树,鉴定该菌为Bacillus velezensis。利用对峙实验测定了该菌的抑菌谱,发现该菌对大丽轮枝菌、尖孢镰刀菌、灰葡萄孢菌、立枯丝核菌、疮痂链霉菌等多种植物病原微生物有明显的抑菌作用。利用硫酸铵盐析法分离纯化活性物质,并对其理化性质进行初步探索显示:抑菌活性物质经60°C、80°C处理20 min后的抑菌活性不变;经100°C处理20 min,活性降低为原来的75.3%;经120°C处理20 min后抑菌活性完全丧失。对胰蛋白酶、胃蛋白酶、蛋白酶K、氯仿、紫外光均不敏感,SDS-PAGE检测发现该抑菌活性物质中含有分子量约为50 kD的蛋白质,初步推测该菌分泌的抑菌活性物质主要是蛋白质类物质。实验表明,该抗菌蛋白能够抑制大丽轮枝菌菌丝的生长及孢子的萌发,为该菌用于生物防治提供了理论基础。     

月腺大戟根总黄酮对尖孢镰刀菌抑制作用的研究

采用生长速率法和孢子萌发法分别测定月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发的抑制率,显微观察总黄酮处理尖孢镰刀菌后菌丝体形态结构的变化,并测定菌丝体相对电导率,菌丝体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果表明:月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发均有显著的抑制作用,抑制率随总黄酮浓度增加而增高,20 mg/L时抑制率达100%。总黄酮处理后的尖孢镰刀菌菌丝较细,分支减少,透明度差,液泡数量增多且形成较大的液泡;菌丝体细胞膜透性增加,SOD、CAT活性呈先上升后下降的趋势。以上实验结果可为植物病害生物防治及开发植物源农药方面提供理论依据和实验技术。     

青霉TS67菌株活性产物的抗真菌作用

本文初步探讨了青霉TS67(Penicillum sp.)的发酵活性产物对植物病原真菌的抑制作用机理,实验结果表明,用其50%的发酵液分别处理玉蜀黍平脐蠕孢菌(Bipolarismaydis)和大豆尖孢镰刀菌(Fusarium oxysporum)120 h后,菌丝生长的抑制率分别为77.78%和70.30%,对孢子产生的抑制率分别达58.8%和73.5%:同时发现用50%发酵液处理病原茵的无性繁殖孢子12 h后,孢子萌发抑制率分别达78.3%和62.O%.经显微镜观察抗菌活性物质处理后的菌丝体,发现菌丝体表面瘤状畸形、菌丝生长顶端不规则膨胀、内部发生原生质浓缩,初步推测青霉TS67主要通过影响植物病原真菌的细胞壁而实现抑制作用.     

黄曲霉毒素生物防控菌的筛选及鉴定

筛选黄曲霉毒素生物防控菌,为黄曲霉毒素的生物防控提供支持。以花生原产地土壤为材料,采用牛津杯法筛选所需菌株。对筛选出的拮抗菌株进行抑制产毒曲霉菌株的生长、产孢、降解黄曲霉毒素实验。筛选出2株黄曲霉毒素生防细菌,编号21-1-2、17-3,经鉴定,拮抗菌21-1-2为枯草芽胞杆菌,拮抗菌17-3为地衣芽胞杆菌。分别对拮抗菌对曲霉孢子萌发的抑制、抑制黄曲霉的生长和菌丝延长以及减少黄曲霉毒素的产生、对黄曲霉毒素的分解作用等几个方面进行研究,结果表明,拮抗菌可以明显抑制产毒曲霉孢子的萌发、生长、菌丝的延长,减少黄曲霉毒素的产生以及分解黄曲霉毒素。     

内生细菌B10对稻瘟病菌抑制作用的初步研究

目的:研究内生细菌B10对水稻稻瘟病菌的抑制作用,为菌株的应用提供理论依据。方法:采用菌丝生长速率法、孢子萌发法和田间试验测定内生细菌发酵上清液和菌液对稻瘟病菌的抑制作用。结果:内生细菌B10发酵上清液对稻瘟病菌菌丝生长和孢子萌发有较强的抑制作用,100倍稀释液对菌丝生长的抑制率为79.37%,对孢子萌发的抑制率为63.42%,对稻瘟病的田间防治效果达70.2%以上。结论:内生细菌B10对稻瘟病有较强的抑菌作用。     

灵芝S_3发酵培养基的优化及其对镰刀菌的抑制

以发酵液对镰刀菌孢子萌发的抑制率为指标,通过单因素试验,研究不同碳源、氮源、生长因子对灵芝S3发酵液抑菌活性的影响。运用响应面法,对各营养组分的含量进行优化。优化后碳源、氮源、生长因子含量分别为:乳糖3.04%,蛋白胨0.28%,VB1 0.0047%,抑菌率为91.71%,比基础发酵培养基增加了42.15%。发酵液作用12h后,光学显微镜下镰刀菌菌丝出现膨大和消融等畸变,并出现典型的"念珠状"形态;透射电镜显示镰刀菌孢子内出现大量空泡、原生质收缩,说明灵芝S3发酵液中的活性物质可有效抑制菌丝生长及孢子萌发。     

根际放线菌I06—03431产生的核苷类抗生素3431的研究

在抗稻瘟菌农用抗生素的筛选过程中,从60多种中药植物根际土壤获得的放线菌中发现,放线菌106—03431的发酵液具有强抗稻瘟菌的活性。经色谱分离纯化,获得活性成分3431,经光谱学数据分析,证明3431为已知核苷类抗生素,丰加霉素（Toyocamycin）：进一步生物活性研究表明,0．005μg／mL的3431能够抑制稻瘟菌孢子萌发和菌丝生长。另外,3431还具有与植物生长调节剂6-苄基腺嘌呤（6-BA）一样的抑制拟南芥根生长的活性。     

Initiation of DNA replication in Bacillus subtilis. IV. The effect of an intercalating dye, ethidium bromide

Summary The effects of an intercalating dye, ethidium bromide (EtBr), on the initiation of chromosome replication in Bacillus subtilis were studied. Spores of a thymine requiring mutant acquired the ability to initiate one round of replication in the absence of RNA and protein synthesis (initiation potential) during germination in a thymine starved medium. When EtBr was added after the initiation potential was fully established, initiation of replication was completely inhibited. This inhibition was reversible, and initiation was resumed when the drug was removed. The recovery of initiation occurred in the absence of protein synthesis but did require RNA synthesis and an active dna gene product.During germination both a DNA-protein complex and a DNA-membrane complex were formed at the replication origin in parallel with the establishment of initiation potential. EtBr destroyed both of these complexes at the concentration which inhibited initiation.The first round of replication of a plasmid DNA, pSL103, during spore germination was also prevented by EtBr. However a higher concentration was required to inhibit plasmid replication. It was found that the plasmid formed two complexes identical to the S- and M-complex of the chromosome origin. Compared to the chromosome complexes the plasmid complexes were less sensitive to EtBr. The loss of sensitivity was equivalent to that for the initiation of the plasmid compared to the chromosome. These results indicate that the target of EtBr is the DNA in the S- and M-complexes whose conformation is essential for the initiation of chromosome and plasmid replication.III of this series is Murakami et al. 1976     

Determination of anti-microbial properties of Ocimum viride concentrations on Rhizopus stolonifer infection and germination of soybean (Glycine max L. Merill)

Investigation was conducted to determine the anti-microbial properties of different concentrations of Ocimum viride and germination of soybean. Analysis of variance recorded a highly significant difference on the percentage occurrence of different fungal diseases at 5% probability level. Ocimum viride at 0.04 ppm had the highest mycelia growth inhibition 77.0%, while 0.00 ppm (control) recorded the lowest mycelia inhibition 1.00% of Rhizopus stolonifer. Investigation revealed that spot recorded the highest percentage occurrence 50%, scab 34%, mould 43% and blight 31.0% recording the lowest. Also the microorganisms isolated from diseased soybean were Rhizopus stolonifer, Fusarium oxysporum, Aspergillus species although the inhibition was very high on Rhizopus stolonifer, followed by Aspergillus sp, then mould when Fusarium sp was low. Also, Ocimun viride extract was observed to possess a high anti-microbial properties as it inhibited the growth of all the micro-organisms identified to be associated with the soybean sees. Result showed that seeds treated with crude extract of 0.04ppm had the highest percentage germination irrespective of the days of germination, followed by 0.03 ppm, then 0.02 ppm, when 0.00 ppm had the lowest. However, 0.01 and 0.02 ppm, respectively, recorded similar percentage germination 64%; 64% at 4 days after planting. Days of planting were highly significant on the percentage germination at 5% probability level, as germination of the soybean seeds increased with days of planting and highest percentage germination of 98% was recorded on the 6th day of planting while no germination was recorded from the 1st till the 4th day of planting.     

Synthesis and antifungal activity of aromatic bis-gamma-lactones analogous to avenaciolide

Avenaciolide is a bis-gamma-lactone isolated from Aspergillus avenaceus and possesses antifungal activity. Here, we describe the total syntheses and characterization by elemental analyses, and IR and NMR spectroscopy of three new bis-gamma-lactones analogous to avenaciolide, where the octyl group of the natural product was replaced by aromatic groups. The effects of the avenaciolide, the novel compounds, and their synthetic precursors on the mycelia development and conidia germination of Colletotrichum gloeosporioides were evaluated in vitro. The new compounds were as active as avenaciolide in the tested conditions, while the synthetic precursors were inactive. The preparation and characterization of 15 new synthetic intermediates are also described.