松材线虫携带细菌产生抑制真菌的物质

研究发现松材线虫携带的两株荧光假单胞菌GcM5-1A、ZM4A和恶臭假单胞菌ZpB1-2A具有抑制真菌菌丝生长的作用.首先对供试的8个细菌菌株进行抑菌活性生物测定,从中筛选出3个具有抑菌活性的细菌菌株;接着对细菌培养液及滤液、死细菌及活细菌进行生物测定;最后对细菌代谢物的性质进行生物测定.实验证明抑制真菌菌丝生长的活性成分为松材线虫携带细菌的挥发性代谢产物.     

肉桂枝枯病菌毒素的研究

本文是对肉桂枝枯病病原菌毒素研究的首例报道。生物活性测定显示，病菌知液体培养基中可产生导致内桂嫩梢萎蔫和叶盘褐变坏死的致病毒素。改良Fries液体培养基振荡培养和PD液体培养基青止培养为较好的产毒培养方式。病原菌毒素为非寄主专化性毒素，除肉桂外，还对香樟、马尾松、薇苷菊、卤地菊和番茄等植物具有致萎活性，毒素为弱酸性（pH5.4），对冷、热稳定性强，极性较大，易深于水、乙醇、丙酮、正丁醇＋丙桐及乙酸乙酯，部分溶于氯仿，基本不溶于乙醚。研究表明毒素为非蛋白质、多糖及核酸类大分子物质。含毒滤液可能含有糖醛类物质，其致毒活性经乙醇和丙酮纯化后有所增强，经HPLC分离出的组分I可能为毒性成份。肉桂叶盘经毒素处理后，其相对电导率较对照大幅度增加，感病的本地桂比抗病的大叶青化桂增加更为明显。     

松材线虫携带的一株致病细菌对非寄主植物的毒性及对黑松LOX酶活性的影响

在实验中发现松材线虫携带的一株致病菌株荧光假单孢菌Pseudomonas fluorescens GcM51A毒素液对玉米、小麦、木耳菜和油麦菜均有毒害作用。以松针为材料，用不同浓度的毒素液处理，测定不同时间内松针细胞脂氧和酶活性的变化。结果表明毒素原液处理的松针LOX活性在处理后的18h达到高峰，随后逐渐下降；稀释5倍处理的松针LOX活性在6～12h呈上升趋势，之后逐渐下降。     

杨树内生菌球毛壳抗生物质的培养基优化、检测和动力学

以杨树内生真菌球毛壳ND35为供试菌株,采用L<,16>(4<'5>)正交试验法对液体培养基进行优化;利用pH纸色谱、捷克八溶剂系统纸色谱方法及紫外-可见光谱扫描法对该内生菌的抗生物质进行理化性质初步分析;用薄层层析、高效液相色谱及平板抑菌法检测分析该菌粗提液的活性成分及对杨树腐烂病菌的抑菌效果;对抗生物质液体培养的主要动力学指标进行分析.结果表明:优化后培养基配方为:1%葡萄糖,1%蔗糖,0.5%牛肉膏,0.02%硫酸亚铁,0.01%维生素B<,1>,pH值为7.球毛壳ND35菌株的抑菌作用分为活菌体的抑菌作用和代谢活性物质的抑菌作用,液体培养后的菌丝胞内和胞外均产生抗生物质,并具有较好的热稳定性.该抗生物质pH值为7,易溶于有机溶剂,难溶于水.球毛壳ND35抗生物质在221 nm处有最大的吸收峰,该抗生物质有4个组分,均对杨树腐烂病菌有抑菌活性.生长动力学表明,在液体发酵培养过程中,球毛壳ND35抗生物质的产量、吸光值、pH及其抑菌率是连续变化的.     

绿僵菌产毒素能力及产毒素动态分析

以绿僵菌素A(DxtA)和绿僵菌素B(DxtB)的产量为指标,分析了僵菌属5个种15个菌株液体培养的产毒素能力差异,确定了高产毒素优良菌株,并拟合了高产毒菌株在摇瓶条件下的产毒素动态.结果表明,不同种绿僵菌间的产毒素能力差异极显著(P<0.01),黄绿绿僵菌(Metarhizium flavoviride)、戴氏绿僵菌(M. taii)和蚱蜢绿僵菌(M. acridum)均不产生毒素,鳞腮绿僵菌(M. lepidiotae)可产少量毒素,金龟子绿僵菌(M. anisopliae)产毒素能力最强,其中M19的DxtA产量最高(144.12 μg·mL-1), M25菌株的DxtB产量最高(65.31 μg·mL-1);M25菌株的综合表现最佳;M25菌株在液体摇瓶培养条件下DxtA产量经SPSS拟合,符合Logist模型:Y=84.99/(1+11.82×e-0.3X),即前4 d是营养生长,毒素分泌量较少,4 d后生物量维持平衡,第5天起毒素产量进入指数增长期,9 d后毒素产量进入平台期.     

核桃炭疽病生物防治菌株YB-4-15的筛选和鉴定

核桃炭疽病给云南核桃产业的发展造成了严重的影响。为给核桃炭疽病生物防治制剂的开发提供理论支撑,以核桃炭疽病菌为指示菌,采用土壤稀释平板法及对峙培养法,对生防菌株进行了分离与筛选,结果表明:菌株YB-4-15、YB-8-11-1、YB-7-9-1对核桃炭疽病菌均有80%以上的抑菌活性,其中,抑菌作用最稳定、抑菌效果最佳的菌株为YB-4-15。然后对YB-4-15菌株进行了形态学鉴定和ITS分析,鉴定结果表明:YB-4-15菌株为钩状木霉菌。最后,对该木霉菌的生物学特性及次生代谢产物的性质进行了研究,结果表明:该菌最适温度为28℃,其菌丝生长对光照条件不敏感,适合在p H为4~8的PDA培养基上生长,其无菌滤液的热稳定性较差,仅在45℃及以下温度条件下才有较好的抑菌效果。     

产漆酶半知真菌Myrothecium verrucaria NF-08菌株的分离及产酶研究

[目的]采集凉水国家级自然保护区原始森林土壤样品,分离产漆酶真菌并优化产酶条件,旨在开发产漆酶半知真菌种质资源,提高漆酶产量,为微生物漆酶扩大生产提供菌种资源和条件参数.[方法]以木质素磺酸钠为唯一碳源的无机盐培养基为富集培养基,在愈创木酚-PDA选择性平板上分离产漆酶真菌.利用ABTS[2,2 ′-连氮一双(3-乙基苯并噻唑-6-磺酸)]和SGZ [4-羟基-3,5-二甲氧基一苯甲醛连氮,即丁香醛联氮]显色反应初筛和摇瓶发酵复筛.确定供试菌株后,利用形态观察结合rDNA-ITS序列分析技术,将菌株鉴定至种.以ABTS法测定供试菌发酵液漆酶活性,以Lowry法测定发酵液总蛋白含量.在考察供试菌株生长、产酶及胞外蛋白总量动态变化基础上,通过单因素试验,研究碳源种类及浓度、氮源种类及浓度、培养基起始pH、装液量、接种量及底物诱导对菌株产漆酶的影响,获得菌株产酶最适培养基组分和培养条件参数.[结果]获得1株发酵周期短、初始酶活高的产酶菌株NF-08.结合形态学特征与rDNA-ITS序列分析结果,鉴定菌株NF-08属于为半知菌亚门疣孢漆斑菌.该菌株在液体发酵培养基中产漆酶活性与菌丝生长和胞外蛋白总量基本同步,发酵第6天达到酶活峰值9.28 U·mL-1.疣孢漆斑菌NF-08产酶最佳碳、氮源分别为4.0％葡萄糖和3.5％蛋白胨,培养基初始pH7.0.最适装液量60 mL·(250 mL)-1,最适接种量4％,最适培养温度和摇床转速分别为30℃和140 r·min-1.没食子酸、阿魏酸和单宁酸显著诱导疣孢漆斑菌NF-08漆酶活性的产生,以没食子酸效果最好.经过培养基组分和培养条件优化以及底物诱导,疣孢漆斑菌NF-08产酶水平达到16.82 U·mL-1,比优化前提高了81.25％.[结论]建立环境样品中产漆酶真菌的分离、纯化及筛选方法,获得了一株发酵周期短、产漆酶活力高的半知真菌疣孢漆斑菌NF-08.该菌株经单因素试验产酶条件优化效果明显,酶活水平提高显著,可为微生物发酵产漆酶提供新的菌株资源,在微生物发酵漆酶工业生产中具有应用潜力.后续对疣孢漆斑菌NF-08漆酶产生、性质及基因表达调控的深入研究,将有助于了解漆酶在半知真菌生活史中的作用及生态学功能,同时拓展半知真菌漆酶的应用领域.     

四川松针上散斑壳菌致病毒素的确定及其致病性差异研究

生物活性测定表明,针叶树散斑壳真菌、松针散斑壳真菌、四川散斑壳真菌及二郎山散斑壳真菌在液体培养基中均可产生导致其寄主针叶枯死的致病毒素。研究表明4种散斑壳真菌毒素均为非蛋白质类组分,结合电导率的测定,发现4种毒素对其来源寄主松针及其他几种松针的毒性存在着差异,其中四川散斑壳真菌所分泌的毒素致病性相对最强。通过对3种不同科属杂草和雪松针叶的生物测定,得出4种毒素均为非寄主专化性毒素。     

具有解磷能力的相思根瘤菌的筛选

对海南、福建、广州、清新分离的根瘤菌和实验室保存的部分根瘤菌进行了解磷能力的研究,从200多株根瘤菌中筛选出40株具有解磷能力的菌株,通过测定根瘤菌在固体培养基和液体培养基中溶解无机磷和有机磷的能力,筛选出2株解磷能力较强的菌株G7-3和菌株DH001.菌株G7-3在无机磷和有机磷培养基中的解磷量分别是4.142、9.944 μg·mL-1,与其它菌株有明显的差异;在无机磷液体培养基中,菌株DH001微克菌体解磷量为0.086 7 μg,和其它菌株有显著差异.对筛选出的菌株进行了16S rDNA测序分析,确定筛选出的菌株除H1-1-1和H2-1-2外,其它菌株均为根瘤菌.     

青枯假单胞杆菌对木麻黄致病机理的初步研究

通过用病原菌悬浮液及培养滤液等对木麻黄无根苗和有根苗进行接种处理，发现青枯菌ＰｓｅｕｄｏｍｏｎａｓｓｏｌｏｎａｃｅａｒｕｍＥ．Ｆ．Ｓｍｉｔｈ培养滤液对木麻黄具有强烈的致萎作用。小苗枯萎主要是由滤液中毒性物质诱导植物产生填充体堵塞导管所致。细菌培养滤液中毒性物质对热稳定，在ｐＨ４～１０的范围内毒性不受影响，而且能够致萎多种针阔叶树种小枝，具有非特异性     

Mutual influences in growth and reproduction between pine wood nematode Bursaphelenchus xylophilus and bacteria it carries

The interactions between pine wood nematode and three bacterium strains isolated from the nematode, Bursaphelenchus xylophilus, which are two strong pathogenic bacterium strains, Pseudomonas fluorescens GcM5-1A and Pseudomonas putida ZpB1-2A and a weak-pathogenic bacterium strain, Pantoea sp. ZM2C, were studied. The result showed that the strong-pathogenic GcM5-1A strain and ZpB1-2A strain significantly increased fecundity, reproduction rate, and the body volume of the adult nematode. Meanwhile, pine wood nematodes significantly promoted reproduction of the two strong-pathogenic bacterium strains. However, the weak-pathogenic bacterium strain, ZM2C, completely inhibited reproduction of pine wood nematodes. Aseptic pine wood nematodes significantly inhibited reproduction of the strain ZM2C. The results indicated that mutualistic symbiosis exists between pine wood nematodes and the two pathogenic bacteria it carries. The phenomenon showed that the pathogenic bacteria carried by the nematode were not accidentally contaminated, but rather had existed as symbionts of the nematode with which it had coevoluted over a long period. The role of mutualistic symbiosis in the process of pine wilt disease was also discussed. __________ Translated from Journal of Nanjing Forestry University, 2005, 29(3): 1–4 [译自: 南京林业大学学报, 2005, 29(3): 1–4]     

Bioactivity of gentiopicroside from the aerial parts of Centaurium erythraea

Gentiopicroside (1), a secoiridoid glycoside isolated from the methanol extract of the aerial parts of Centaurium erythraea, has been assessed for antibacterial and free radical scavenging activities. General toxicity of 1 has also been determined by brine shrimp lethality bioassay.     

白僵菌代谢提取物对美国白蛾毒性生测方法的研究

以美国白蛾幼虫为试虫，采用饲喂、口服、表皮接触和血腔注射4种生测方法测定了白僵菌代谢提取液的毒性。结果表明，4种生测方法代谢提取液均表现一定的毒性，血腔注射生测所表现的毒性最高。通过对着4种生测方法的比较分析，建议白僵菌的代谢物中毒素物质的生物测定首先采用血腔注射法生测。     

白僵菌代谢蛋白对松墨天牛毒性生测方法试验

从白僵菌代谢物中提取蛋白类毒素用于防治松墨天牛,以松墨天牛幼虫为试虫,采用饲喂、口服、表皮接触和血腔注射4种生测方法测定了白僵菌蛋白类代谢物提取液的毒性。结果表明,4种生测方法样品均表现一定的毒性,血腔注射生测所表现的毒性最高。通过对4种生测方法的比较分析,表明白僵菌代谢物中毒素物质的毒性采用血腔注射法最容易检测到。     

Effects of some bacteria (Pseudomonas spp. and Erwinia herbicola) on in vitro growth of Piptoporus betulinus

Summary Bacteria including Pseudomonas putida, Pseudomonas fluorescens biovar I, Pseudomonas fluorescens biovar V, Pseudomonas aureofaciens and Erwinia herbicola were isolated from discoloured zones in birch trunks. Antagonistic effects of these bacteria to growth of Piptoporus betulinus mycelium were tested in vitro, both in dual culture and using bacterial cell‐free culture filtrates. In dual cultures, P. putida was most effective at inhibiting mycelial growth of Piptoporus betulinus. Filtrates of P. putida inhibited growth of P. betulinus mycelium irrespective of filtrate concentration, incubation time of bacteria and timing of recording mycelium growth. The strongest antagonistic effect (inhibition of fungal growth) was observed on a medium containing 80% of sterile filtrate obtained from 15‐day‐old bacterial cultures. The highest stimulating effect on mycelium growth was noted on medium containing 80% filtrate obtained from 7‐day‐old E. herbicola cultures.     

Biological activity of serotonin conjugates from the seeds of Centaurea nigra

Two serotonin conjugates, N-(trans-p-coumaroyl)-serotonin (1) and N-(trans-feruloyl)-serotonin (maoschamine, 2), isolated from the methanol extract of the seeds of Centaurea nigra, have been assessed for antibacterial and free radical scavenging activities. The general toxicity of 1 and 2 has also been determined by the brine shrimp lethality bioassay.     

城市树木生长质量的检测

城市绿化树木的核心功能是为城市居民的工作和生活提供一个良好的生态环境,与此同时对它们的基本要求就是要安全,不能对人们造成任何形式和程度的伤害。但由于城市所处环境的特殊性,城市绿化树木的生长质量普遍不是很好,例如连云港市一条主干道两侧的树木有80%存在不同程度的树干腐朽现象(瞿世涛等,2003)。存在健康问题的树木在恶劣天气条件下(如大风、大雪、暴风雨等)容易折断,从而容易给人们生命、财产带来危害,是城市生活重要的安全隐患之一。我国地域辽阔、历史悠久,各个城市几乎都有很多古树名木。这些古树名木不仅是重要的自然景观,也…     

Anti-inflammatory, cyclooxygenase inhibitory and antioxidant activities of standardized extracts of Tridax procumbens L.

The standardized EtOAc, MeOH and 70% EtOH extracts of Tridax procumbens aerial parts showed significant inhibition of rat paw edema at a medium dose of 200 mg/kg and the EtOAC extract was the most active. These extracts were standardized by HPLC with the help of chemical markers. Further, the extracts were evaluated for COX-1 and COX-2 inhibitory activity and EtOAc extract exhibited the highest inhibition of COX-1 and COX-2 at 50 μg/mL. Cent aurein, centaureidin and bergenin were isolated as COX-1 and COX-2 inhibitory principles from the EtOAc extract. The extracts also exhibited antioxidant activity against DPPH and ABTS free radicals. The anti-inflammatory activity of T. procumbens aerial parts could be at least in part due to COX-1, COX-2 enzyme inhibition and free radical-scavenging activities which may be attributed to the presence of flavonoids and other polyphenols in the extracts.