产恩拉霉素链霉菌的诱变及其发酵条件的优化

为满足恩拉霉素工业化生产对高产菌株的需求,采用N+注入技术和单因素及正交试验方法对产恩拉霉素链霉菌(Streptomyces sp.)NJWGY3665进行诱变,并对目的菌株的最佳发酵条件进行优化。结果表明:随N+注入剂量的增加,菌株的存活率呈典型的马鞍型剂量-效应曲线。在最佳注射剂量120×1013ions/cm2条件下筛选到1株具有遗传稳定性的高产链霉菌突变菌株LD1;该菌株发酵最适培养基条件为蔗糖50g/L,酵母粉20g/L,NaCl 1.5g/L,FeSO_40.5g/L;最佳发酵条件为转速190r/min,温度28℃,pH 7,接种量8%。在此条件下,发酵液恩拉霉素浓度达11 860μg/mL。     

富硒链霉菌wh63的鉴定及富硒特性研究

富硒链霉菌wh63可在平板硒浓度为100 mg/L时生长良好。低浓度的硒元素可以促进菌株生长,高浓度则会抑制菌株的生长,硒添加量为0.5和1.0 mg/L的wh63菌株生物量比对照分别提高12%和8%。通过显微形态学观察,wh63菌株孢子丝卷曲,孢子表面光滑;在高氏1号培养基上,气生菌丝为白色,后期颜色会变深。结合16S r DNA序列分析鉴定,发现其与唐德链霉菌(Streptomyces tendae)的同源性最高,为99%,且生理生化特性一致,初步鉴定wh63菌株为链霉菌属(Streptomyces)。通过菌落形态观察,结合SEM(扫描电镜)和IR(红外光谱)分析,发现链霉菌wh63可以将无机硒转化为红色单质硒,红色单质硒附着在富硒链霉菌wh63菌体表面。     

拮抗链霉菌Men-myco-93-63及其发酵液对棉花黄萎病菌生长的影响

本研究采用抑菌圈法和菌落生长法测定桔抗链霉菌 Ｍ ｅｎ－ｍｙｃｏ－ ９３－ ６３（５２３）及其发酵液对棉花黄萎病菌（Ｖｅｒｔｉｃｉｌｌｉｕｍ ｄａｈｌｉａｅ）Ｔ－９和河北省强致病力菌株Ｖ－ｈ菌体生长的影响。结果表明：链霉菌Ｍｅｎ－ｍｙｃｏ－９３－６３及其发酵液对棉花黄萎病菌菌体具有强烈的抑制作用,明显降低了棉花黄萎菌的生长量。同时发现,拮抗链霉菌及其发酵液对不同致病菌株表现不同的抑菌效果;Ｍｅｎ－ｍｙｃｏ－９３－６３发酵稀释液可使Ｖ．ｄａｈｌｉａｅ出现融菌现象。     

Unique Cyclized Thiolopyrrolones from the Marine-Derived Streptomyces sp. BTBU20218885

Two new cyclized thiolopyrrolone derivatives, namely, thiolopyrrolone A (1) and 2,2-dioxidothiolutin (2), together with the kn own compound, thiolutin (3) were identified from a marine-derived Streptomyces sp. BTBU20218885, which was isolated from a mud sample collected from the coastal region of Xiamen, China. Their chemical structures were determined using spectroscopic data, including HRESIMS, 1D and 2D NMR techniques. 1 possessed a unique unsymmetrical sulfur-containing thiolopyrrolone structure. All the compounds were tested for bioactivities against Staphylococcus aureus, Escherichia coli, Bacille Calmette–Guérin (BCG), Mycobacterium tuberculosis, and Candida albicans. 1 displayed antibacterial activities against BCG, M. tuberculosis, and S. aureus with minimum inhibitory concentration (MIC) values of 10, 10, and 100 μg/mL, respectively. Thiolutin (3) showed antibacterial activities against E. coli, BCG, M. tuberculosis, and S. aureus with MIC values of 6.25, 0.3125, 0.625, and 3.125 μg/mL, respectively.     

农用抗生素TS99产生菌YH9407的初步研究

从辽宁省丹东地区的土壤样品中分离到一株新的杀真菌链霉菌YH9407,其产生的次级代谢产物对多种植物病原真菌和细菌有较强的抑制作用。该菌株在各种合成培养基上生长良好 ,气生菌丝和孢子堆为灰白色 ,基内菌丝一般为浅黄色 ,有的可产生黄色可溶性色素 ;孢子丝柔曲或直立 ,直径为0.17～0.22μm,孢子呈球形或卵圆形 ,直径为(0.6～0.8)μm×(0.8～1.2)μm ;通过与杀真菌链霉菌已知种在形态特征、培养特征和生理生化特性方面的比较 ,YH9407为杀真菌链霉菌的一个新菌株 ,暂命名为StreptomycesfungicidicusNo.9407     

Field assessment of composts produced by highly effective cellulolytic microorganisms

 In a newly cultivated sandy soil, sugar beet haulms composted by highly effective cellulose-decomposing microorganisms (Trichoderma viride NRC6 or Streptomyces aureofaciens NRC22) were evaluated as organic manure for tomato plants (Lycopersicon esculentum L. cv. Supermarmment). The treatments were as follows: (1) control with NPK, (2) farmyard manure (FYM), (3) uninoculated compost, (4) compost inoculated with Glomus sp. NRC212, (5) compost produced by T. viride NRC6, (6) compost produced by S. aureofaciens NRC22. The organic amendments differed in their effects on total microbial counts in the rhizosphere of tomato plants. However, the amendment of soil with compost produced by highly effective cellulose-decomposing microorganisms or compost inoculated with arbuscular mycorrhizal (AM) fungi decreased the proliferation of the total bacteria in the rhizosphere of tomato plants compared with FYM or compost. The application of compost produced by T. viride NRC6 or S. aureofaciens NRC22 enriched the rhizosphere with fungi or Streptomyces more than the other manure treatments. FYM and compost enhanced both spore production and the percentage of mycorrhizal root infection of tomato plants as compared with the NPK treatment, while compost produced by T. viride NRC6 or S. aureofaciens NRC22 reduced both the mycorrhizal spore numbers and the percentage of mycorrhizal root infection as compared with the NPK treatment. However, the application of FYM or compost reduced the incidence of root rot by 8% and 32%, respectively, as compared with the NPK treatment. The use of T. viride NRC6 or S. aureofaciens NRC22 as cellulolytic microorganisms and AM fungi as inocula in the applied compost increased plant protection by 80%, 75%, and 73%, as compared with the NPK treatment, respectively. No significant differences in plant dry weight, N, P content and tomato yield were obtained between FYM and the mineral fertilizer treatment. However, different types of compost induced a significant increase in plant dry matter, N and P uptake and fruit yield relative to the FYM and mineral fertilizer treatments. Received: 17 February 1999     

拮抗链霉菌防治马铃薯疮痂病的大田试验研究

 本文报道了利用拮抗链霉菌防治马铃薯疮痂病的大田试验研究。拮抗链霉菌接种在0.8公顷的病田中。不同接种量和接种方法均显著地影响防治效果。3年的试验表明:拮抗菌系以蛭石接种形式防效优于种薯浸泡。一般情况下,连续2年接种或高接种量的防效优于1年或低接种量的防效。不同菌系的防效差异明显,单个拮抗菌的防效优于2个拮抗菌混合使用的效果。甜玉米和大豆轮作结合拮抗菌显著降低了马铃薯疮痂病的危害。     

铁矿尾矿放线菌分离株的系统发育分析

[目的]通过确定12株典型分离株的系统发育地位,初步探讨铁矿尾矿中放线菌生物多样性。[方法]采用酚-氯仿法提取基因组DNA,PCR扩增16S rDNA并测序后进行系统发育分析。[结果]12株铁矿尾矿放线菌均属于链霉菌属,与进化关系最近的已知菌株同源性为98.7%～100%。[结论]铁矿尾矿中可培养放线菌类群以链霉菌为主,其中存在大量潜在的新种。     

龟裂链霉菌M527荧光定量PCR内参基因的选择及其稳定性评估

龟裂链霉菌Streptomyces rimosus M527是龟裂霉素（rimocidin）的生产菌，其对多种植物病原真菌具有较强的拮抗作用。为从转录水平分析菌株M527以及其抗性突变株中龟裂霉素的合成调控机制，荧光定量PCR内参基因的选择与稳定性评估显得尤为重要。本研究选用16S rRNA_sr、hrdB_sr、rpoA_sr、sigF_sr、sigB_sr、gyrB_sr这6个基因作为候选内参基因，使用geNorm、NormFinder、BestKeeper三个软件分析在野生型龟裂链霉菌M527、高产龟裂霉素抗性突变株M527-GR7和低产龟裂霉素抗性突变株M527-GR21中候选内参基因的稳定性，筛选出稳定性最高的内参基因。结果显示，sigB_sr基因在菌株M527及抗性突变株M527-GR7和M527-GR21中表达稳定性最好。通过以基因sigB_sr、16S rRNA_sr、rpoA_sr为内参基因，检测龟裂霉素生物合成基因簇中的结构基因rimG_sr在菌株M527-GR7中不同时间的相对表达量，发现基因sigB_sr作为内参基因时能得到更准确的结果。     

黄瓜枯萎病拮抗放线菌S24的分离、鉴定及发酵条件优化

为了筛选黄瓜枯萎病拮抗放线菌,从蔬菜温室大棚及附近土壤中分离了59株菌落形态有差异的放线菌,通过平板对峙筛选试验,获得2株对黄瓜枯萎病菌抑菌率在60％以上的放线菌,分别是S21和S24,其中 S24的抑菌率达到74％。根据形态特征、生理生化特性和分子分类测定结果,初步将S24鉴定为黄麻链霉菌（Streptomyces corchorusii）。选用7种常用的放线菌发酵培养基对S24进行发酵,7 d后测定发现,5号培养基发酵上清液对黄瓜枯萎病菌的抑制活性最强,抑菌率达到59.44％,其细胞破碎液对黄瓜枯萎病菌的抑菌率为39.76％。通过比较发现,75 mL为放线菌S24的最适发酵装液量（250 mL三角瓶）。采用正交试验优化后的培养基进行发酵,获得的上清液及细胞破碎液对黄瓜枯萎病菌的抑菌率分别达到76.14％、52.27％,较优化前分别提高了14.64、10.11个百分点。