产杀虫活性物质海洋放线菌的筛选和初步鉴定

从浙江宁波海域的滩涂泥样中分离到54株海洋放线菌,用卤虫液体测定法进行了杀虫活性菌株的筛选,结果显示多株放线菌具有较高的杀虫活性,菌株XS902,XS904,BL803,BL807对卤虫的ID50高达100以上。同时研究了XS904活性菌株的形态培养特征和生理生化特征,初步鉴定该菌株属于链霉菌属。     

广西茅尾海红树林土壤放线菌多样性及功能酶活性研究

研究广西茅尾海红树林自然保护区内红树林土壤中可培养放线菌的多样性,挖掘具有高产多种功能酶活性的放线菌类群.应用可培养技术和基于16S rRNA基因序列的系统发育分析研究红树林土壤中可培养放线菌的多样性;并以10种酶活底物为指示物,结合点植法和透明圈法对可培养的放线菌进行功能酶活性筛选.结果显示,从红树林土壤中共分离到4...     

广西红树林根际土壤放线菌的原位培养分离及其活性筛选

为了发掘广西红树林根际土壤的放线菌资源,本文利用原位培养装置,埋于根际土壤中俘获放线菌,30d后取回实验室,采用平板涂布法对4个地点的原位培养样品于15种培养基上进行分离纯化;对分离株基于16SrRNA基因序列进行系统发育分析;进一步进行抗菌活性和产酶活性检测。共分离得到113株放线菌。对其中33株放线菌进行测序,结果表明20株属于链霉菌属,11株属于拟诺卡氏菌属,1株属于伦兹氏菌属,1株与拟诺卡氏菌属相似性最高为90%,很可能属于放线菌一个新属。抗菌实验结果显示其中有7株、4株、18株、6株、10株、3株实验菌株分别对大肠埃希菌、铜绿假单胞菌、金黄色葡萄球菌、普通变形杆菌、乙型溶血性链球菌和肺炎克雷伯氏菌具有抑制作用;有55株、62株、24株、72株的实验菌株分别具有纤维素酶活性、淀粉酶活性、胶原蛋白酶活性、酯酶活性。原位培养可以丰富对广西红树林根际土壤的认识,分离到了新种甚至可能是新属的放线菌,分离得到的部分放线菌菌株具有较高生物活性,为后续工作提供了良好的实验材料。     

Diversity and bioactivity of actinomycetes from marine sediments of the Yellow Sea

Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.     

Isolation and phylogenetic assignation of actinomycetes in the marine sediments from the Arctic Ocean

Actinomycetes in five marine sediments collected from the Arctic Ocean at depths of 43 to 3 050 m were cultivated using a variety of media. A total of 61 actinomycete colonies with substrate mycelia only were observed, and no colonies with aerial mycelia were observed under aerobic conditions at 15 ℃. From these colonies, 28 were selected to represent different morphological types.Denaturing gradient gel electrophoresis (DGGE) was used to check the purity of isolates and select representatives for subsequent sequencing. Phylogentic analyses based on nearly full-length 16S ribosomal RNA gene (rDNA) sequences indicated that the actinomycetes isolated were accommodated within genus Rhodococcus of family Nocardiaceae, genus Dietzia of family Dietziaceae,genera Janibacter and Terrabacter of family Instrasporangiaceae and genera Kocuria and Arthrobacter of family Micrococcaceae. One of the strains (P27-24) from the deep-sea sediment at depth of 3 050 m was found to be identical in 16S rDNA sequence(1474/1474)with the radiation-resistant Kocuria rosea ATCC 187T isolated from air. More than halfofthe isolates showed the similarities ranging from 99.5% to 99.9% in 16S rDNA sequence to dibenzofran-degrading, butyl 2-ethylhexanoate-hydrolysising and nitrile-metabolizing actinomycetes. All the strains isolated were psychrotolerant bacteria and grew better on the media prepared with natural seawater than on the media prepared with deionized water. Three of them (Dietzia sp. P27-10, Rhodococcus sp. S11-3 and Rhodococcus sp.P11-5)had an obligate growth requirement for salt, confirming that these strains are indigenous marine actinomycetes.     

南大西洋深海沉积物中可培养放线菌的多样性

探究了南大西洋深海沉积物中可培养放线菌的多样性,筛选药源活性次级代谢产物产生菌,为后续资源开发奠定基础.采用3种预处理方法及8种选择性培养基对南大西洋3个深海沉积物样品中的放线菌菌株进行选择性分离鉴定;利用兼并引物扩增法,选取代表菌株进行聚酮合酶（PKSⅠ、PKSⅡ）基因和非核糖体多肽合成酶（NRPS）基因的检测;以4株细菌为指示菌检测代表菌株的抑菌活性.共分离得到132株放线菌纯菌株,分布于放线菌亚纲的6个目、13个科、19个属中,其中有5个属为较新或较稀有种属,有2株为潜在新种.34株化合物合成基因检测菌中PKSⅠ基因、PKSⅡ基因呈阳性的比率均为17.64%,NRPS基因呈阳性的则为52.94%.抗枯草芽孢杆菌（Bacillus subtilis）和抗副溶血性弧菌（Vibrio parahaemolyticus）的菌株分别有47.06%和7.82%.南大西洋深海沉积物中放线菌资源丰富,存在较多潜在新分类单元,筛选到的活性菌株可用于后续药源活性次级代谢产物的分离.     

产免疫调节活性多糖海洋放线菌的筛选

用硫酸苯酚法和实验动物模型检测分离于厦门海区潮间带的996株海洋放线菌胞外多糖产量和体内外免疫增强活性.结果表明,33%的海洋放线菌粗多糖产量大于3g/dm3;在粗多糖产量高的海洋放线菌中有3株菌株的胞外多糖在体内外均具有较好的免疫增强活性,其中链霉菌(Streptomyces sp.)2305菌株的胞外多糖具有较高的非特异性、细胞及体液免疫增强活性.研究结果表明海洋放线菌胞外多糖是免疫调节剂开发的重要资源.     

海洋放线菌ACMA006抗肿瘤活性成分的分离纯化及结构鉴定

对从中国江苏连云港海域中筛选出的海洋放线菌ACMA006的发酵产物进行了分离纯化,获得2种抗肿瘤活性化合物,并进一步鉴定其结构．海洋放线菌ACMA006经大规模发酵后,发酵液采用溶剂萃取法提取其中的抗肿瘤活性成分,并利用硅胶柱层析、制备薄层及HPLC等方法对萃取物进行分离得到单体化合物．利用红外光谱、质谱、核磁共振‘H—HMR谱和”C—NMR谱等波谱数据对单体化合物的结构进行解析和鉴定．结果表明化合物B为放线菌素D,其分子式为c62：H86N12016含有2个多肽酯环,由L一苏氨酸、D一缬氨酸、L．脯氨酸、N一甲基甘氨酸和L—N一甲基缬氨酸组成,通过羧基与发色母核吩唾嗪酮相连接．化合物A可能为放线菌素D的衍生物．这是国内外首次从海洋放线菌中分离提取出放线菌素D．     

Inhibition of Aspergillus parasiticus and cancer cells by marine actinomycete strains

Ten actinomycete strains isolated from the Yellow Sea off China's coasts were identified as belonging to two genera by 16 S r DNA phylogenetic analysis: Streptomyces and Nocardiopsis. Six Streptomyces strains(MA10, 2SHXF01-3, MA35, MA05-2, MA05-2-1 and MA08-1) and one Nocardiopsis strain(MA03) were predicted to have the potential to produce aromatic polyketides based on the analysis of the KSα(ketoacyl-synthase) gene in the type II PKS(polyketides synthase) gene cluster. Four strains(MA03, MA01, MA10 and MA05-2) exhibited significant inhibitory effects on mycelia growth(inhibition rate 50%) and subsequent aflatoxin production(inhibition rate 75%) of the mutant aflatoxigenic Aspergillus parasiticus NFRI-95. The ethyl acetate extracts of the broth of these four strains displayed significant inhibitory effects on mycelia growth, and the IC50 values were calculated(MA03: 0.275 mg m L-1, MA01: 0.106 mg m L-1, MA10: 1.345 mg m L-1 and MA05-2: 1.362 mg m L-1). Five strains(2SHXF01-3, MA03, MA05-2, MA01 and MA08-1) were selected based on their high cytotoxic activities. The ethyl acetate extract of the Nocardiopsis strain MA03 was particularly noted for its high antitumor activity against human carcinomas of the cervix(He La), lung(A549), kidney(Caki-1) and liver(Hep G2)(IC50: 2.890, 1.981, 3.032 and 2.603 μg m L-1, respectively). The extract also remarkably inhibited colony formation of He La cells at an extremely low concentration(0.5 μg m L-1). This study highlights that marine-derived actinomycetes are a huge resource of compounds for the biological control of aflatoxin contamination and the development of novel drugs for human carcinomas.     

双河洞放线菌多样性和抗菌活性的初步研究——以阴河洞和杉林洞为例

放线菌是微生物中重要的药用菌,其产生的抗生素是20世纪医学皇冠上最耀眼的明珠,但随着抗生素滥用,抗生素耐药现象日趋严重,因此从特殊生态环境中发现新放线菌物种和新抗生素克服耐药是科研人员正在尝试的途径之一,文章初步探究双河洞系统中阴河洞和杉林洞两个支洞的放线菌多样性,并对分离菌株的抗菌活性进行筛选。以纯培养方法获得放线菌,以16S rRNA基因序列比对,分析菌株类别,获得的菌株进行液体发酵,纸片琼脂扩散法测定其发酵产物对真菌和细菌的抗菌活性,同时用PCR技术进行NRPS、PKS I和PKS II抗生素生物合成基因的探测。从两个支洞样品中分离到的放线菌分布于7个科10个属,两个洞共66株放线菌中有32株的发酵产物在至少一个抗菌活性筛选中显示阳性,总阳性率为48.5%。抗生素生物合成基因的初步探测结果显示,31株菌存在至少一个生物合成基因,NRPS 28株,PKS I17株,PKS II 21株,其中12株同时具有3种生物合成基因。初步显示了双河洞系统蕴含丰富的放线菌资源,值得深入研究。