Two antimycin A analogues from marine-derived actinomycete Streptomyces lusitanus

Two new antimycin A analogues, antimycin B1 and B2 (1-2), were isolated from a spent broth of a marine-derived bacterium, Streptomyces lusitanus. The structures of 1 and 2 were established on the basis of spectroscopic analyses and chemical methods. The isolated compounds were tested for their anti-bacterial potency. Compound 1 was found to be inactive against the bacteria Bacillus subtilis, Staphyloccocus aureus, and Loktanella hongkongensis. Compound 2 showed antibacterial activities against S. aureus and L. hongkongensis with MIC values of 32.0 and 8.0 μg/mL, respectively.     

海洋放线菌F-1013对几丁质的利用及其发酵液的优化

研究了分离自海洋虾壳的一株放线菌F-1013对几丁质的利用及其发酵液的优化。结果表明：该菌具有较高的几丁酶活力。通过对该菌发酵液的筛选和优化,认为该菌在pH8-9、5%的虾壳粉培养液中发酵5-7d,甲壳低聚糖含量达到0.3mg.mL-1,产菌量优于其他基质的培养基。     

生防放线菌153固态发酵条件的优化及其耐热力检测

【目的】探讨生防放线菌153的固态发酵条件,并考察其耐热力,为生防放线菌的大规模生产及活体菌剂的研制提供技术支持。【方法】将发酵物的含菌量作为筛选指标,以玉米粉、甘油、蔗糖、葡糖糖和可溶性淀粉为碳源,以小米粉、蛋白胨、酵母浸粉、黄豆粉和尿素为氮源,通过单因素试验获得适宜的碳、氮源,再采用L25(56)正交设计优化固体培养基配方,在此基础上确定固态发酵终点以及所需的接种量和种子液种龄。最后将壳聚糖、非耕作层黄土、高岭土、炉渣、碳酸钙、面粉和几丁质分别与生防放线菌153菌粉混合,55℃水浴至致死中时,测定生防放线菌153的耐热力,筛选适宜的载体。【结果】生防放线菌153固体培养基配方为:80mg/g麦麸、8mg/g玉米粉、10mg/g小米粉和2mg/g蛋白胨,初始含水量(含0.5g/L石灰的自来水)为60%,在此条件下培养,培养物的含菌量较对照增加了94.1%。生防放线菌153固态发酵培养终点为216h,接种量为20%(每100g固态培养基接种20mL种子液),种子液种龄为84h。生防菌153的适宜载体为壳聚糖和非耕作层黄土。【结论】确定了生防放线菌153的固态发酵条件,该条件可以促进生防菌153的生长产孢,并提高菌株的保存稳定性;确定了筛选生放菌153载体的方法,即55℃条件下水浴处理136min。     

防治辣椒疫病的生防放线菌固体发酵培养基优选试验

采用固体发酵的方式研究了2株防治辣椒疫病生防放线菌固体发酵培养基的种类和配方。结果表明:采用固态发酵工艺培养2株生防放线菌可获得活孢子数高的生防菌剂。玉米粉是适于A3和A5的2株放线菌固态发酵优良C、N源物质,玉米粉Ⅴ培养基可作为2株生防放线菌共同发酵的固态培养基质。     

New Benzoxazine Secondary Metabolites from an Arctic Actinomycete

Two new secondary metabolites, arcticoside (1) and C-1027 chromophore-V (2), were isolated along with C-1027 chromophore-III and fijiolides A and B (3–5) from a culture of an Arctic marine actinomycete Streptomyces strain. The chemical structures of 1 and 2 were elucidated through NMR, mass, UV, and IR spectroscopy. The hexose moieties in 1 were determined to be d-glucose from a combination of acid hydrolysis, derivatization, and gas chromatographic analyses. Arcticoside (1) and C-1027 chromophore-V (2), which have a benzoxazine ring, inhibited Candida albicans isocitrate lyase. Chromophore-V (2) exhibited significant cytotoxicity against breast carcinoma MDA-MB231 cells and colorectal carcinoma cells (line HCT-116), with IC₅₀ values of 0.9 and 2.7 μM, respectively.     

人参锈腐病菌拮抗放线菌JY36发酵条件研究

对人参锈腐病拮抗放线菌JY36的发酵条件进行研究,确定了其最佳培养基组成及培养条件。单因素试验和正交试验结果表明,最佳斜面固体培养基为3号培养基,最佳种子培养基为4号培养基,最佳发酵培养基为6号培养基。最适发酵时间为120 h,最适发酵培养温度为30℃,最适初始pH值为7。     

木麻黄根瘤内生菌的分离、培养和回接*

从福建、广东、海南岛的木麻黄根瘤中分离到16株内生菌，它们都具有Frankia菌的典型形态特征。回接鉴定表明，除4株不侵染原寄主植物外，其余12株均具有侵染能力，但各菌株的侵染能力不同，这些菌株在培养基上的培养特征有一定的差异，实验菌株在BAP培养基上生长最好，在Jan B10m,Qmold等培养基上生长较差。     

苹果树腐烂病菌拮抗放线菌JPD-1的筛选及鉴定

为筛选对苹果树腐烂病菌Valsa mali具有拮抗作用的放线菌,从苹果树根际土壤中分离获得放线菌,利用平板对峙法和生长速率法筛选拮抗活性较高的菌株,通过菌株培养特征、形态特征、生理生化特性及16S rDNA序列分析确定其分类地位,并采用离体枝条烫伤接种法测定所筛选获得的拮抗菌株对苹果树腐烂病的防效。结果表明,从苹果树根际土壤中共分离获得28株放线菌,其中菌株JPD-1对苹果树腐烂病菌的拮抗作用最强,抑制率为72.50%,该菌在高氏合成1号培养基上生长最好,培养7 d时菌落生长旺盛,气生菌丝白色,基生菌丝深粉红色,无可溶性色素产生;经形态特征观察、生理生化试验及16S rDNA序列分析,将菌株JPD-1鉴定为公牛链霉菌Streptomyces tau‐ricus。菌株JPD-1发酵滤液对苹果树腐烂病菌的抑制率及对离体枝条上苹果树腐烂病的防效均随稀释倍数的增大而减弱,发酵滤液原液使苹果树腐烂病菌菌丝膨大、末端畸形,抑制率为78.14%,对离体枝条上苹果树腐烂病的防效为76.37%。表明分离到的放线菌菌株JPD-1可以用作苹果树腐烂病的生防材料,具有很好的开发及应用前景。     

放线菌Lj20抗真菌物质的分离及其在病害防治中的作用

菌株Lj20是从健康辣椒植株分离得到的一株有杭真菌活性的植物内生放线菌,为了进一步明确其生物防治潜力,利用大孔吸附树脂、离心薄层层析以及柱层析等技术对Lj20代谢产物中的抗真菌活性物质进行了分离和提纯,并采用生长速率法测定了其代谢产物对黄瓜灰霉病菌的抑制作用,同时在温室中对Lj20发酵液粗提物的防病效果进行了试验.从Lj20代谢产物中分离得到一个抗真菌活性物质,该化合物时黄瓜灰霉病菌具有较强抑制作用,EC50值为174.94 mg/L;500mg/LLj20发酵液粗提物对黄瓜灰霉病的防治效果达62.5%;经鉴定其化合物结构为3,5-二叔丁基-4-羟基-卞基甲醚.结果表明,放线菌Lj20有进一步开发和利用的价值.     

Deoxyuridines from the marine sponge associated actinomycete Streptomyces microflavus

One new nucleoside derivative, named 3-acetyl-5-methyl-2'-deoxyuridine (1), along with two known compounds 3,5-dimethyl-2'-deoxyuridine (2) and 3-methyl-2'-deoxyuridine (3), were isolated from the cultures of Streptomyces microflavus. This strain was an associated actinomycete isolated from the marine sponge Hymeniacidon perlevis collected from the coast of Dalian (China). Their structures were elucidated by detailed NMR and MS spectroscopic analysis as well as comparison with literature data.