棉铃虫人工饲料主要污染细菌鉴定及其抗生素筛选

棉铃虫的人工饲养是对其进行昆虫病原菌生物测定的重要步骤,而饲料污染是影响棉铃虫培养成功率的主要因素。因此,选择合适的抗生素对棉铃虫的饲养具有重要意义。为明确棉铃虫饲料中污染细菌的组成,筛选可抑制污染菌的抗生素,本研究以受污染棉铃虫饲料中分离出的9个菌株为实验材料,观察菌株形态。采用16S rDNA系统发育分析法构建进化树,同时根据药敏与生理生化实验,确定分离菌株的生理生化特性。结果表明,9个菌株共呈现5种生理生化特性,其中,2株与肠球菌属(Enterococcus sp.)接近,2株与埃希氏菌属(Escherichia sp.)接近,2株与志贺氏菌属(Shigella sp.)接近,2株与肠杆菌属(Enterobacter sp.)接近,1株与沙雷氏菌属(Sarratia sp.)接近。抗生素筛选实验结果显示,卡那霉素对于不同菌株的抑菌效果最好。这为提高棉铃虫人工饲养成活率具有重要意义。     

海洋链霉菌S007次生代谢产物的分离鉴定(英文)

采用柱层析、制备薄层层析等方法从海洋链霉菌S007的发酵液提取物中分离得到了9个化合物,经波谱分析确定为嘧啶(1),吡咯-2-羧酸(2),卡拉霉素(3),3-吲哚丙酸(4),吲哚-3-羧酸(5),N-乙酰基酪胺(6),2’-胸腺嘧啶脱氧核苷(7),N-β-乙酰色胺酸(8)和三乙胺盐酸盐(9)。其中三乙胺盐酸盐是首次从链霉菌中得到;海虾致死实验结果显示:化合物3在40μg/mL浓度下对丰年虾的致死率为86.5%,表明卡拉霉素对丰年虾表现出很强的毒性作用。     

海洋链霉菌Streptomyces sp. SCSIO 1672及其代谢产物水杨酸的分离鉴定

从南海海洋沉积物中分离得到1株海洋放线菌,鉴定为链霉菌Streptomyces sp. SCSIO 1672。通过优化发酵条件,采用海虾生物致死活性和高效液相色谱追踪,利用有机溶剂萃取、正相硅胶、反相硅胶等各种色谱层析方法分离出活性化合物,通过波谱数据解析出海洋放线菌SCSIO 1672次级代谢产物中的该活性化合物为水杨酸。     

Draft genome sequence of marine Streptomyces sp. strain W007, which produces angucyclinone antibiotics with a benz[a]anthracene skeleton

A series of angucyclinone antibiotics have been isolated from marine Streptomyces sp. strain W007 and identified. Here, a draft genome sequence of Streptomyces sp. W007 is presented. The genome contains an intact biosynthetic gene cluster for angucyclinone antibiotics, which provides insight into the combinatorial biosynthesis of angucyclinone antibiotics produced by marine streptomycetes.     

A bleaching herbicidal activity of methoxyhygromycin (MHM) produced by an actinomycete strain Streptomyces sp. 8E-12

AIMS: To screen bioherbicidal isolates and evaluate herbicidal activity of methoxyhygromycin (MHM) produced by Streptomyces sp. 8E-12. METHODS AND RESULTS: Streptomyces sp. 8E-12 with herbicidal activity was selected through seed germination bioassay. An active metabolite, MHM was isolated from culture broth by carbon absorption, butanol extraction, silica gel, Sephadex LH-20 and G-10 chromatography, and preparative HPLC. The metabolite was identified by electrospray ionization mass spectra (ESI-MS) and 1H- and 13C-NMR spectral data analyses. In vivo herbicidal activity was examined against weeds and crops grown on pots. CONCLUSIONS: Streptomyces sp. 8E-12 produced a selective herbicidal metabolite which was identified as MHM. The metabolite showed stronger in vivo activity against monocotyledonous plants than dicotyledonous plants, and caused a bleaching (albino symptom) on some weeds including Digitaria sanguinalis and Echinochloa crus-galli. SIGNIFICANCE AND IMPACT OF THE STUDY: These results showed that Streptomyces sp. 8E-12 produced a bioherbicidal metabolite, MHM and can be developed as a biocontrol agent (BCA) for weed control.     

Besarhanamides A and B from the marine cyanobacterium Lyngbya majuscula

Besarhanamides A (1) and B (2) are fatty acid amides purified from the marine cyanobacterium, Lyngbya majuscula, collected from Pulau Hantu, Singapore. The structure determination of these secondary metabolites was carried out using extensive 2D NMR spectral data as well as chemical manipulations including the Marfey's method. In addition, besarhanamide A exhibited moderate toxicity with LD(50) at 13 microM in the brine shrimp toxicity bioassay.     

海洋微生物杀虫活性筛选方法比较

采用活体昆虫浸渍法和细胞毒性测定法对海洋微生物发酵液进行了杀虫活性比较,从294株供试菌株中,共筛选出7株活性较好的菌株;对Lv7-1、02AB8 a、T31和BBY-9四株菌株,在不同时间的生物量、发酵液pH值与细胞毒活性等方面的关系进行了研究。     

Biodegradation of shrimp processing bio-waste and concomitant production of chitinase enzyme and N-acetyl-D-glucosamine by marine bacteria: production and process optimization

A total of 250 chitinolytic bacteria from 68 different marine samples were screened employing enrichment method that utilized native chitin as the sole carbon source. After thorough screening, five bacteria were selected as potential cultures and identified as; Stenotrophomonas sp. (CFR221?M), Vibrio sp. (CFR173?M), Phyllobacteriaceae sp. (CFR16?M), Bacillus badius (CFR198?M) and Bacillus sp. (CFR188?M). All five strains produced extracellular chitinase and GlcNAc in SSF using shrimp bio-waste. Scanning electron microscopy confirmed the ability of these marine bacteria to adsorb onto solid shrimp bio-waste and to degrade chitin microfibers. HPLC analysis of the SSF extract also confirmed presence of 36-65?% GlcNAc as a product of the degradation. The concomitant production of chitinase and GlcNAc by all five strains under SSF using shrimp bio-waste as the solid substrate was optimized by 'one factor at a time' approach. Among the strains, Vibrio sp. CFR173?M produced significantly higher yields of chitinase (4.8 U/g initial dry substrate) and GlcNAc (4.7?μmol/g initial dry substrate) as compared to other cultures tested. A statistically designed experiment was applied to evaluate the interaction of variables in the biodegradation of shrimp bio-waste and concomitant production of chitinase and GlcNAc by Vibrio sp. CFR173?M. Statistical optimization resulted in a twofold increase of chitinase, and a 9.1 fold increase of GlcNAc production. These results indicated the potential of chitinolytic marine bacteria for the reclamation of shrimp bio-waste, as well as the potential for economic production of chitinase and GlcNAc employing SSF using shrimp bio-waste as an ideal substrate.     

Investigation of anti-inflammatory and toxicity effects of mangrove-derived Streptomyces rochei strain VITGAP173

Mangrove ecosystems generate the major biodiversity hotspots of actinobacteria. Among the actinobacteria, Streptomyces species are the prolific producers of bioactive natural products. In this study, with research efforts to discover biopotential compounds from marine actinobacteria, 41 actinobacterial strains were isolated from sediment soil sample of Indian mangrove regions. The phylogeny prediction using the 16S rRNA gene sequences revealed that the isolates were related to Streptomyces. Isolates were further screened based on a two-step process wherein the first step, around nine strains, unveiled the presence of type 1 polyketide synthase gene and dTDP-glucose 4,6-dehydratase gene through polymerase chain reaction. As the second step of the screening process, cell viability assay was performed in RAW264.7 cells to assess the toxicity of extracts. Among all the isolates, Streptomyces rochei strain VITGAP173 was subjected to further analysis. To explore the bioactivities, the organic solvent extraction method was utilized to extract the broth culture of VITGAP173. Inhibition of nitric oxide and cyclooxygenase enzymes upon lipopolysaccharide-induced inflammation were utilized to evaluate the anti-inflammatory efficacy, and the results showed the potency of VITGAP173 in a dose-dependent manner. The extract significantly suppressed the messenger RNA levels of the inflammatory mediators such as tumor necrosis factor-α and interleukin-6 induced by lipopolysaccharide in RAW264.7 macrophages. The presence of several chemical constituents was identified through gas chromatography-mass spectrometry analysis of VITGAP173 extract. To achieve the toxicity analysis, oral administration of VITGAP173 extract in Wistar albino rats was carried out to investigate the biochemical parameters, histopathology which revealed its nontoxic nature.     

右旋磷霉素生物转化菌株的筛选和鉴定

以右旋磷霉素为唯一碳源进行固体初筛和液体复筛,获得生物转化能力较强的32株菌;再以杀卤虫模型筛选具有杀虫活性物质的菌株,得到一株具有较强杀虫活性的真菌FM94,通过对该菌的形态特征观察及ITS序列分析,鉴定为腾仓赤霉（Gibberella fujikuroi）;初步考察其生物转化条件,结果表明在以右旋磷霉素为唯一碳源,初始pH值为3.5,转化培养第4d时转化产物杀卤虫活性最高。     

Diversity of culturable actinobacteria isolated from marine sponge <Emphasis Type="Italic">Haliclona</Emphasis> sp.

This study describes actinobacteria isolated from the marine sponge Haliclona sp. collected in shallow water of the South China Sea. A total of 54 actinobacteria were isolated using media selective for actinobacteria. Species diversity and natural product diversity of isolates from marine sponge Haliclona sp. were analysed. Twenty-four isolates were selected on the basis of their morphology on different media and assigned to the phylum Actinobacteria by a combination of 16S rRNA gene based restriction enzymes digestion and 16S rRNA gene sequence analysis. The 16S rRNA genes of 24 isolates were digested by restriction enzymes TaqI and MspI and assigned to different groups according to their restriction enzyme pattern. The phylogenetic analysis based on 16S rRNA gene sequencing showed that the isolates belonged to the genera Streptomyces, Nocardiopsis, Micromonospora and Verrucosispora; one other isolate was recovered that does not belong to known genera based on its unique 16S rRNA gene sequence. To our knowledge, this is the first report of a bacterium classified as Verrucosispora sp. that has been isolated from a marine sponge. The majority of the strains tested belong to the genus Streptomyces and three isolates may be new species. All of the 24 isolates were screened for genes encoding polyketide synthases (PKS) and nonribosomal peptide synthetases (NRPS). PKS and NRPS sequences were detected in more than half of the isolates and the different "PKS-I-PKS-II-NRPS" combinations in different isolates belonging to the same species are indicators of their potential natural product diversity and divergent genetic evolution.     

Efficient removal of hexavalent chromium by a tolerant Streptomyces sp. affected by the toxic effect of metal exposure

AIMS: To isolate and analyse chromium-resistant micro-organisms suitable for bioremediation. METHODS AND RESULTS: Strain CG252, with a minimal inhibitory concentration of 500 microg ml(-1), was isolated from contaminated soils and identified as a Streptomyces sp. by 16S rDNA sequence analysis. Assays carried out at various Cr(VI) concentrations indicated that chromium removal was more efficient at lower concentrations and that this activity resulted in accumulation of Cr(III). Atomic adsorption analysis indicated that the chromium removed was not associated with cell mass and activity assays showed that the capacity to reduce Cr(VI) was most probably due to a soluble cytosolic enzyme. Cells grown as biofilms showed enhanced removal of Cr(VI) with respect to planktonic cells, while analysis of growth and colony morphology indicated that Cr(VI) had a toxic effect on this strain. CONCLUSIONS: Streptomyces sp. CG252 tolerated heavy metals and elevated levels of chromium, despite its negative effect on growth and development, and was efficient at removing Cr(VI) by promoting reduction to Cr(III). SIGNIFICANCE AND IMPACT OF THE STUDY: Strain CG252's capacity to tolerate heavy metals and to reduce Cr(VI) to the less toxic Cr(III), especially when forming biofilms, makes it a promising candidate for detoxification of sites containing this heavy metal.     

Indoloditerpenes from an algicolous isolate of Aspergillus oryzae

Two new indoloditerpene derivatives asporyzin A (1) and asporyzin B (2), one new indoloditerpene asporyzin C (3), and three known related indoloditerpenes JBIR-03 (4), emindole SB (5), and emeniveol (6) were isolated from an endophytic fungus Aspergillus oryzae, isolated from the marine red alga Heterosiphonia japonica. Their structures were unambiguously established by spectroscopic techniques. In addition, all the isolates were evaluated preliminarily for insecticidal and antimicrobial activities in order to probe into their chemical defensive function. Compound 4 was more active against brine shrimp than the others, and 3 possessed potent activity against Escherichia coli.     

海洋放线菌Streptomyces sp.大片段DNA基因组文库的构建

目的:构建稀有海洋放线菌Streptomyces sp.基因组文库.方法:以稀有海洋放线菌Streptomyces sp.为实验材料,随机剪切提取的总DNA,5'-磷酸末端补平回收40kb左右的DNA片段,与pWEBTM载体连接,经包装蛋白包装成噬菌体后侵染宿主细胞E.coli EPI100,构建该菌株的基因组文库,并对该文库进行质量鉴定.结果:成功构建了稀有海洋放线菌Streptomyces sp.的基因组文库,效价达9.0×104CFU/mL,得到4000个阳性克隆子,远远大于按覆盖率为99%计算至少所需的837个阳性克降子数,且平均插入片段长度为36kb,重组率100%.阳性克隆子保存于96孔板中,-80℃保存.结论:所构建文库的各项指标均达到要求,为了进一步评估Streptomyces sp.所能合成的所有潜在天然产物,还需要进一步检测该文库中包含有生物合成基因簇的大肠杆菌的表达情况.     

Cristatumins A-D, new indole alkaloids from the marine-derived endophytic fungus Eurotium cristatum EN-220

Four new indole alkaloids, namely, cristatumins A-D (1-4), along with six known congeners (5-10) were identified from the culture extract of Eurotium cristatum EN-220, an endophytic fungus isolated from the marine alga Sargassum thunbergii. The structures of these compounds were established on the basis of extensive spectroscopic analysis. Each of these compounds was evaluated for antimicrobial and insecticidal activity. Compounds 1 and 9 showed antibacterial activity against Escherichia coli and Staphyloccocus aureus, respectively, while compounds 2, 6, and 7 exhibited moderate lethal activity against brine shrimp. Preliminary structure-activity relationships were also discussed.     

Screening fusarium strains isolated from overwintered Canadian grains for trichothecenes

A survey of 38 samples of Canadian overwintered grains showed that 14 (37 %) contained viableFusarium. Of a total of 38Fusarium isolates, cultured on autoclaved corn, 20 (from 7 grain samples) showed toxicity to brine shrimp larvae and 12 (from 5 samples) produced levels of trichothecenes detectable by thin layer chromatography. The principal trichothecene found was T-2 toxin, produced by 10 strains and accompanied in half of these by neosolaniol; some of these strains were identified asF. sporotrichioides Sherbakoff. Two strains ofF. poae (Peck) Wollenw. formed small amounts of diacetoxyscirpenol. T-2 toxin was the most toxic of 8 trichothecenes tested on brine shrimp larvae; the wide range of toxicities limits the usefulness of this bioassay as a general screening method for trichothecenes.     

Toxigenic Fungi in Food

Forty-five fungal isolates from moldy supermarket foods were tested for toxicity to brine shrimp, and twenty-two of these isolates were subsequently tested for toxicity to chicken embryos. Highly toxigenic fungi were Cladosporium sphaerospermum from a bakery product, Fusarium oxysporum from carrots, F. solani from cabbage, Aspergillus niger and Penicillium corylophilum from bread, P. cyclopium and P. herguei from corn meal, P. lanosum from onions,P. steckii from chocolate syrup, Penicillium sp. from jelly, and Rhizopus nigricans isolates from sweet potato, applesauce, and strawberries. Approximately one-third of the fungal cultures were moderately to highly toxigenic to brine shrimp and chicken embryos, while several additional cultures were slightly toxigenic.     

Streptomyces sp. strain isolated from river water has high bisphenol A degradability

AIMS: We report the identification of the bisphenol A (BPA) biodegradability in Streptomyces sp. strain isolated from river water. METHODS AND RESULTS: The water samples spiked with BPA (1 mg l(-1)) and the culture solution of Streptomyces sp. strain were placed at 30 degrees C for 10 days and were analysed by high-performance liquid chromatography. A half-life for BPA degradation was between 3 and 4 days. The removal rate of BPA was >90% for 10 days. CONCLUSIONS: These results show that the Streptomyces sp. strain isolated from river water has high BPA degradability. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of BPA degradation by Streptomyces sp. strain.     

Studies on bacterial flora in the population of the fall webworm, Hyphantria cunea Drury. (Lep., Arctiidae)

Abstract:  In this study, the bacterial flora of Hyphantria cunea Drury. (Lep., Arctiidae) were investigated during three hazelnut seasons from 1998 to 2000. Four different bacteria were found in dead and living larvae. They were isolated and identified as Bacillus thuringiensis , Escherichia freundii , Micrococcus sp. and Streptococcus sp. Laboratory experiments carried out to determine the insecticidal activities of these isolates showed that E. freundii and Micrococcus sp. did not have any insecticidal effect on second – third instar larvae of H. cunea . However, B. thuringiensis and Streptococcus sp. had 56 and 38% effects, respectively. Crystals and spores from B. thuringiensis were also purified and the crystals, spores and crystals–spore mixture were tested separately against the larvae of H. cunea . It was found that the insecticidal activities of the crystals, spores and crystal–spore mixture were 37.5, 25 and 62.5%, respectively, on second – third instar larvae of H. cunea . These results indicate that the crystal–spore mixture has 6.5% more insecticidal effect than that of the vegetative cells of the B. thuringiensis isolate.     

Pharmacological activities of crude acetone extract and purified constituents of Salvia moorcraftiana Wall.

The crude acetone extract of aerial parts of Salvia moorcraftiana Wall. was screened for various biological activities including Lemna bioassay, antifungal, antibacterial, leishmanicidal, insecticidal activities and brine shrimp cytotoxicity. It was found to possess strong phytotoxic activity against Lemna aequinoctials Welve. and moderate antifungal activity against animal and plant pathogens. The purified chemical constituents were tested for enzyme inhibition activity. Two constituents (compounds 3 and 8) were found to be effective inhibitors of alpha-glucosidase.