Deoxyvasicinone with Anti-Melanogenic Activity from Marine-Derived Streptomyces sp. CNQ-617

The tricyclic quinazoline alkaloid deoxyvasicinone (DOV, 1) was isolated from a marine-derived Streptomyces sp. CNQ-617, and its anti-melanogenic effects were investigated. Deoxyvasicinone was shown to decrease the melanin content of B16F10 and MNT-1 cells that have been stimulated by α-melanocyte-stimulating hormone (α-MSH). In addition, microscopic images of the cells showed that deoxyvasicinone attenuated melanocyte activation. Although, deoxyvasicinone did not directly inhibit tyrosinase (TYR) enzymatic activity, real-time PCR showed that it inhibited the mRNA expression of TYR, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2). In the artificial 3D pigmented skin model Melanoderm^TM, deoxyvasicinone brightened the skin significantly, as confirmed by histological examination. In conclusion, this study demonstrated that the marine microbial natural product deoxyvascinone has an anti-melanogenic effect through downregulation of melanogenic enzymes.     

不同菌落形态的链霉菌对产谷氨酰胺转胺酶的影响

通过对链霉菌STK-203进行自然选育,挑选出5种不同菌落形态的单菌落。摇瓶发酵培养48h后检测发酵液中的谷氨酰胺转胺酶的活性、残余氨基氮含量、残余甘油含量、菌种生物量等4种生理指标。结果表明,编号为Ⅰ即馒头型的单菌落的酶活最高,高达5．84U／mL,其残余甘油含量为0．071g／L,残余氨基氮含量为1．48g／L,菌体浓度为36．01％。根据菌落形态和产酶的相关性,为产谷氨酰胺转胺酶的链霉菌STK-203菌株的选育和生产提供了一种简便有效的方法。     

Streptomyces yanglingensis KM-1-2遗传转化体系的建立及 km790的过表达

杨凌链霉菌（Streptomyces yanglingensis）KM-1-2是从银杏种子中分离到的一株新菌,为对其次级代谢产物基因簇进行研究,需建立该菌株的遗传转化体系。通过接合转移的方法成功建立杨凌链霉菌KM-1-2的遗传转化体系,并确定最佳接合转移条件：以2CMY为接合转移培养基,孢子于50 ℃热激10 min,抗生素覆盖时间介于18~19 h,其中萘啶酮酸质量浓度为25 mg/L,安普霉素为3 mg/L,接合转移效率达 1.052×10^-5。同时,利用该转化体系,过表达KM-1-2基因组中的1个SARP转录调控因子km790。与野生型链霉菌KM-1-2相比,过表达菌株Skm790生长速率加快,产孢时间提前,对部分病原真菌的拮抗性增强,而且代谢产物图谱发生明显变化。     

农抗120对水稻纹枯病菌抗生活性试验

采用平板培养法测定农抗120对水稻纹桔菌的抗生试验结果,表明农抗120对水稻纹枯病菌的抗生作用为抑制菌丝生长,使菌丝畸变。菌丝顶端产生不正常的分枝,分枝与主轴成直角,菌丝先端扭曲变形,不形成菌核。农抗120对纹枯菌的抑制生长最低浓度为12.5μg/ml,抑制纹枯菌核形成的最低浓度为100μg/ml,可推迟形成菌核,有效地控制水稻纹枯病流行和扩展。     

胶孢炭疽菌生防放线菌gz-8的鉴定及生物活性初步评价

从山东省临沂地区土壤中分离到一株放线菌gz-8,发现其对胶孢炭疽菌Colletotrichum gloeosporioides具有较强的抑制作用,皿内抑菌活性达72.5%。通过形态特征和生理生化测定,结合16S rDNA序列分析,鉴定该菌株为栗褐链霉菌Streptomyces badius。抗菌谱测定结果表明,菌株gz-8对6种植物病原真菌均具有较强的抑菌活性,抗菌谱较广。进一步对菌株gz-8的粗提物进行了生物活性评价,发现其发酵液粗提物可以明显抑制胶孢炭疽菌的菌丝生长（EC50=3.18 μg/mL）和分生孢子萌发（IC50=1.92 μg/mL）,且活性明显高于菌体粗提物;同时发酵液粗提物具有良好的热稳定性及pH稳定性;1 000 mg/L的发酵液粗提物对感染胶孢炭疽病芒果果实的防效达到35.94%,与同浓度下百菌清的防效（34.11%）无显著差异。     

南方根结线虫拮抗链霉菌的筛选和鉴定

通过生物测定和温室防病试验 ,对分离自江苏省南京、淮阴和上海三地 3 0份土样的 3 44株放线菌菌株进行筛选 ,得到了 1株对南方根结线虫有较高生物活性的链霉菌菌株LH1 2 1。其培养滤液在离体条件下对南方根结线虫二龄幼虫有较强的触杀作用 ,4h内击倒率达 1 0 0 % ,1 2h内致死率达 1 0 0 % ;番茄植株上的活体防病试验表明 ,2ml/株培养滤液对根结和卵块形成的抑制率分别为52 .8%和 63 .5%。遗传稳定性试验表明LH1 2 1菌株能稳定产生杀线活性物质。LH1 2 1培养滤液主要通过直接触杀二龄幼虫或干扰其侵入植株而达到防治目的。根据形态、培养和生理生化特性的分析 ,将LH1 2 1鉴定为玫瑰暗黄链霉菌     

杭白菊枯萎病的病原菌分离鉴定及淀粉酶产色链霉菌对其防治效果

杭白菊枯萎病是杭白菊重要病害之一,枯萎病的爆发对杭白菊产量造成了巨大的影响。为了明确杭白菊枯萎病的病原菌及其生防菌的防治效果,本文通过形态学和ITS序列分析方法,初步鉴定杭白菊枯萎病病原菌为半裸镰刀菌Fusarium incarnatum。进一步采用菌丝生长速率法和孢子萌发法,测定了淀粉酶产色链霉菌Streptomyces diastatochramogenes 1628代谢产物对该病原菌的抑制效果。结果发现,链霉菌1628代谢产物对菌丝生长和孢子萌发的EC₅₀分别为2.22%和4.70%（体积浓度）。盆栽试验结果表明,施用淀粉酶产色链霉菌代谢产物原液14和28 d后,其对杭白菊枯萎病的保护效果、治疗效果分别为52.84%和42.85%、19.23%和30.16%。说明淀粉酶产色链霉菌1628的代谢产物对杭白菊枯萎病具有明显的保护和治疗作用。     

Discovery and Photoisomerization of New Pyrrolosesquiterpenoids Glaciapyrroles D and E,from Deep-Sea Sediment Streptomyces sp.

Two new pyrrolosesquiterpenes, glaciapyrroles D (1) and E (2) were discovered along with the previously reported glaciapyrrole A (3) from Streptomyces sp. GGS53 strain isolated from deep-sea sediment. This study elucidated the planar structures of 1 and 2 using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), and infrared (IR) spectroscopic data. The absolute configurations of the glaciapyrroles were determined by Mosher’s method, circular dichroism spectroscopy, and X-ray crystallography. Under 366 nm UV irradiation, the glaciapyrroles were systematically converted to the corresponding photoglaciapyrroles (4–6) via photoisomerization, resulting in the diversification of the glaciapyrrole family compounds. The transformation of the glaciapyrrole Z to E isomers occurred in a 1:1 ratio, based on virtual validation of the photoisomerization of these olefinic compounds by ¹H-NMR spectroscopy and liquid chromatography/mass spectrometry (LC/MS) analysis. Finally, when encapsulated in poly(lactic-co-glycolic acid) nanoparticles, glaciapyrrole E and photoglaciapyrrole E displayed significant inhibitory activity against influenza A virus. This is the first report of antiviral effects from glaciapyrrole family compounds, whose biological functions have only been subjected to limited studies so far.     

一株海洋放线菌的分类鉴定及抗菌活性研究

从连云港海域潮间带采集的样品中筛选得到1株产广谱、高活性抗菌物质的放线菌GB-2.该菌对藤黄微球菌、蜡样芽孢杆菌、金黄色葡萄球菌等5种革兰氏阳性菌,大肠杆菌、荧光假单胞菌等4种革兰氏阴性菌及扩展青霉、黄曲霉、点青霉、犁头霉、番茄灰霉、小麦赤霉病菌、香蕉炭疽病菌、棉花枯萎病菌、稻瘟病菌等18种真菌有显著拮抗作用.根据其形态特征、培养特征、生理生化特性和16S rRNA序列分析结果,确定其为弗氏链霉菌变种.菌株GB-2所产抗菌物质的稳定性研究表明,该物质在121 ℃ pH 1和pH 12条件下抑菌活性均不变;紫外线照射不影响其抗菌活性.结果揭示该菌在生防、食品及医药方面有潜在的应用价值.     

秦岭链霉菌发酵液中杀虫活性成分分离及结构鉴定

采用大孔树脂层析、硅胶柱层析以及制备高效液相色谱等技术对具有抑菌和杀虫活性的秦岭链霉菌发酵液中的杀虫活性成分进行了分离纯化,得到3个杀虫活性化合物,经高分辨质谱和核磁共振波谱技术分别鉴定为阿维菌素B1a、B2a和A1a。研究发现,同一菌株发酵液中可以同时产生杀虫和杀菌两类成分,与阿维链霉菌Streptomyces avermectinius亲缘关系差异很大的链霉菌也可以产生阿维菌素成分。