代谢物组分析利迪链菌素生物合成代谢转变

为进一步明确利迪链菌素生物合成时从初级代谢到次级代谢的转变，运用ESI-MS和PCA分析，对利迪链霉菌AS 4．2501生产利迪链菌素不同发酵阶段的细胞内外代谢物进行代谢物组研究。结果表明，利用代谢物组学的方法能区分开不同发酵阶段的代谢产物，特别是根据第三主成分（PC3）可明显将细胞进入次级代谢与初级代谢阶段区分开，结合文献和MS／MS分析，推断代谢转变过程的生物标志物主要源于磷脂和蛋白类化合物。     

高通量筛选技术在菌种进化中的研究进展

菌种进化工程是绿色生物制造的重要策略，利用高效的高通量筛选方法和技术可以快速地获得理想的实用菌株。针对菌种进化工程中的高通量筛选方法，本文重点综述了基于颜色或荧光、基于细胞生长、基于生物传感器以及基于液滴微流体平台等4个方面的高通量筛选技术的重要进展，同时也介绍了各种高通量筛选技术的应用范围和特点，为研究人员从不同进化文库中获得生理特性或者代谢能力显著提高的目标菌株提供了理论指导，极大地提高进化文库的筛选效率，降低了菌株筛选的时间和成本。最后展望了人工智能、合成生物学以及生物信息学的发展对高通量筛选技术的重要影响，以期提高高通量筛选技术的精度、效率和应用范围，进而加速菌种进化过程和工业化进程。     

泰乐菌素高产菌株的筛选

以弗氏链霉菌(Streptomyces fradiae)TP-116菌株作为出发菌株,采用紫外线、氯化锂和微波三重复合诱变,通过泰乐菌素抗性定向筛选,获得一株高产菌株YBT-06,并对其进行了遗传稳定性试验,结果表明突变株YBT-06生产代谢旺盛,遗传稳定性好,发酵效价比出发菌株提高了25%,达到11066μg/m L。     

2010年授权的农药专利集锦(十)

具毒杀植物线虫活力的链霉菌的制备方法及其应用本发明涉及一株具毒杀植物线虫作用的链霉菌的培养方法及其代谢物制备方法和应用,属于微生物农药技术领域。本发明涉及的链霉菌菌株Snea253为委内瑞拉链霉菌Streptom ycesvenezue-lae,已于2008年1月18日保藏在中国微生物菌种保藏管理委员会普通微生物中心(地址:北京市     

防治作物真菌病害新农药——武夷菌素

武夷菌素是一种高效、广谱、低毒的大公害生物农药,其产生菌为不吸水链霉菌武夷变种,主要活性组分武夷菌素A为结构全新的具有胞苷骨架的核苷类抗生素。武夷菌素能通过干扰病原菌蛋白质的合成而起到防治真菌病害的作用,对黄瓜白粉病等作物真菌病害的防治效果为70％～98％。菌种选育获得的高产菌株摇瓶发酵水平稳定在4000μg/ml以上,并已实现工业化生产。     

防治作物真菌病害新农药——武夷菌素

武夷菌素是一种高效、广谱、低毒的无公害生物农药,其产生菌为不吸水链霉菌武夷变种,主要活性组分武夷菌素A为结构全新的具有胞苷骨架的核苷类抗生素.武夷菌素能通过干扰病原菌蛋白质的合成而起到防治真菌病害的作用,对黄瓜白粉病等作物真菌病害的防治效果为70%～98%.菌种选育获得的高产菌株摇瓶发酵水平稳定在4000μg/ml以上,并已实现工业化生产.     

风化煤的微生物转化:Ⅱ.作用机理(待续)

微生物能够利用风化煤中的碳，本文采用离心过滤，结合加热处理，得到无菌滤液和无酶活性滤液，再加入风化煤进行培养，对4株真菌：青霉菌GRF4，镰抱霉菌WF2、未知菌LF1和根霉AHBPF2和2株放线菌(浅黄链霉菌ACBPA1，沙阿雷素链霉菌B2cA2)转化风化煤的机理进行了初步的研究，发现不同菌株对风化煤中不同组分的转化能力不同，菌体存在对一些菌株转化风化煤十分必要，而另一些菌株依赖螯合作用和酶解作用。     

防治作物真菌病害新农药——武夷菌素

武夷菌素是一种高效、广谱、低毒的无公害生物农药,其产生菌为不吸水链霉菌武夷变种,主要活性组分武夷菌素A为结构全新的具有胞苷骨架的核苷类抗生素.武夷菌素能通过干扰病原菌蛋白质的合成而起到防治真菌病害的作用,对黄瓜白粉病等作物真菌病害的防治效果为70%～98%.菌种选育获得的高产菌株摇瓶发酵水平稳定在4000μg/ml以上,并已实现工业化生产.     

放线菌BOS-009的分离、拮抗活性及鉴定

对从长白山不同海拔环境中分离筛选出可以产生抗菌活性物质的BOS-009放线菌菌株进行了研究,测定了该菌的抗菌谱,发现该菌株对多种植物病原性真菌及细菌有拮抗作用.通过形态特征、培养特征观察,生理生化特性及抑菌谱等系列比较.发现该菌株与链霉菌属的除虫链霉菌(Streptomyces avermitilis)的特征基本相符;通过16s rDAN序列比对,发现该菌株16s rDAN与除虫链霉菌的16s rDAN同源性达99%.根据多项分类原则和系统进化树的构建分析,将该菌株暂归入除虫链霉菌类.     

核糖霉素高产菌株的选育

以核糖苷链霉菌03-8为出发菌株，经紫外线和氯化锂的复合处理得到一株产核糖霉素的能力比出发株提高27.8%的菌株。对该菌株再采用微波诱变，筛选自身产物抗性解除反馈调节变株，同时结合单菌落自然分离纯化法，得到了稳定高产菌株563-44是一株高产的工业生产菌种。     

丙酸盐影响利迪链霉菌AS 4.2501生产利迪链菌素及其碳流分布

To achieve higher antibiotic streptolydigin productivity through metabolic regulation, propionate was fed during the fermentation of Streptomyces lydicus AS 4.2501. The effects of propionate feeding on streptolydigin production and intracellular fluxes were investigated. The highest streptolydigin production yield of 95.10mg·L^-1 was obtained when 2mmol·L^-1 of sodium propionate was added at 60h of cultivation into shake-flask culture. This yield is 23.06% higher when compared to that of a batch culture without propionate supplementation. It was also found that when propionate was added, much more organic acids were excreted. Metabolic flux analysis was performed and it demonstrated that the carbon fluxes of the pentose phosphate pathway and the anaplerotic reaction were significantly increased after propionate feeding. The carbon flux from pyruvate to acetyl-CoA was determined to be 24.7, which was 12.27% higher than that in the batch culture. This study indicated that the glucose-6-phosphate and pyruvate nodes were potential bottlenecks for increasing streptolydigin productivity. Potential targets and strategies that could be manipulated through genetic and process engineering to increase the production of streptolydigin were also suggested.     

氮源对利迪链菌素生产及相关次级代谢物分布的影响

The effects of nitrogen sources on streptolydigin production and distribution of secondary metabolites were investigated for flask cultured S.lydicus AS 4.2501.When peptone,asparamide,and glutamic acid were ex- amined as the nitrogen source,respectively,liquid chromatography-mass spectrometry（LC-MS）and photodiode array（PDA）analyses revealed the formation of two analogues of streptolydigin in the fermentation broth.When soybean meal was used as the source of nitrogen,three analogues of streptolydigin were detected.The use of am- monium sulfate as a source of nitrogen resulted in a lower pH value of the fermentation system,thus inhibiting streptolydigin biosynthesis and changing the metabolic profiling.Among the nitrogen sources that were made use of,glutamic acid was most favorable to the formation of streptolydigin.Simultaneously,this study also showed that the changing nitrogen sources resulted in altering the production and relative ratios of streptolydigin and its analogues.     

Biosynthesis of Colabomycin E,a New Manumycin‐Family Metabolite,Involves an Unusual Chain‐Length Factor

Colabomycin E is a new member of the manumycin‐type metabolites produced by the strain Streptomyces aureus SOK1/5‐04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of “lower” carbon chains were constructed and expressed in S. aureus SOK1/5‐04 ΔcolC11–14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain‐length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL‐1β release from THP‐1 cells and might thus potentially act as an anti‐inflammatory agent.     

螺旋链霉菌的推理选育

以螺旋链霉菌25-1为出发菌株,分别采用紫外线(UV)、Co60射线、甲基磺酸乙酯(EMS)、氯化锂(LiCl)、UV+LiCl、亚硝基胍(NTG)+UV进行诱变筛选,比较各方法的致死率、正变率、最大提高幅度及对传代稳定性的影响,结果发现UV、Co60射线、UV+LiCl 3种方法对螺旋链霉茵的诱变效果较好,化学诱变剂...     

Streptomyces phospholipase D mutants with altered substrate specificity capable of phosphatidylinositol synthesis

The substrate specificity of a phospholipase D (PLD) from Streptomyces antibioticus was altered by site-directed saturation mutagenesis, so that it was able to synthesize phosphatidylinositol (PI). Mutations were introduced in the pld gene at the positions corresponding to three amino acid residues that might be involved in substrate recognition, and the mutated genes were expressed in Escherichia coli BL21 (DE3). High-throughput screening of approximately 10,000 colonies for PI-synthesizing activity identified 25 PI-synthesizing mutant PLDs. One of these mutant enzymes was chosen for further analysis. The structure of the PI synthesized with the mutant enzyme was analyzed by HPLC-MS and NMR. It was found that the mutant enzyme generated a mixture of structural isomers of PIs with the phosphatidyl groups connected at different positions of the inositol ring. The phosphatidylcholine-hydrolyzing activity of the mutant PLD was much lower than that of the wild-type enzyme. The mutant enzyme was able to transphosphatidylate various cyclohexanols with a preference for bulkier compounds. This is the first example of alteration of the substrate specificity of PLD and of PI synthesis by Streptomyces PLD.     

Metabolomic Fingerprinting for the Detection of Early-Stage Lung Cancer: From the Genome to the Metabolome

The five-year survival rate of lung cancer patients is very low, mainly because most newly diagnosed patients present with locally advanced or metastatic disease. Therefore, early diagnosis is key to the successful treatment and management of lung cancer. Unfortunately, early detection methods of lung cancer are not ideal. In this brief review, we described early detection methods such as chest X-rays followed by bronchoscopy, sputum analysis followed by cytological analysis, and low-dose computed tomography (LDCT). In addition, we discussed the potential of metabolomic fingerprinting, compared to that of other biomarkers, including molecular targets, as a low-cost, high-throughput blood-based test that is both feasible and affordable for early-stage lung cancer screening of at-risk populations. Accordingly, we proposed a paradigm shift to metabolomics as an alternative to molecular and proteomic-based markers in lung cancer screening, which will enable blood-based routine testing and be accessible to those patients at the highest risk for lung cancer.     

Improving thermostability of phosphatidylinositol-synthesizing Streptomyces phospholipase D

Aimed to produce thermostable phosphatidylinositol (PI)-synthesizing phospholipase D (PLD), we initiated site-directed combinatorial mutagenesis followed by high-throughput screening. Previous site-directed combinatorial mutagenesis of wild-type Streptomyces PLD produced a mutant, DYR (W187D/Y191Y/Y385R) with PI-synthesizing ability. Deriving PI as a product of transphosphatidylation between phosphatidylcholine and myo-inositol, with myo-inositol in excess at high-temperature reaction conditions can increase yield due to enhanced solubility of this substrate. Thus, we improved DYR's thermostability by introduction of random mutations into selected amino acid positions having high B-factor. Screening of the libraries under restricted conditions yielded single-point mutants, specifically D40H, T291Y and R329G. Combinations of these point mutations yielded double (D40H/T291Y, D40H/R329G and T291Y/R329G) and triple (D40H/T291Y/R329G) mutants. PI synthesis at elevated temperatures pointed at D40H/T291Y as the most efficient enzyme. Circular dichroism analysis revealed D40H/T291Y to have increased melting temperature and postponed onset of thermal unfolding compared with DYR. Thermal tolerance study at 65°C confirmed D40H/T291Y's thermostability as its half-inactivation time was 8.7 min longer compared with DYR. This mutant had significantly less root-mean-square deviation change compared with DYR and showed no change in root-mean-square fluctuation when temperature shifts from 40 to 60°C, as determined by molecular dynamics analysis. Acquired different degrees of thermostability were also observed for several other DYR mutants.     

Functional Characterization of Different ORFs Including Luciferase‐Like Monooxygenase Genes from the Mensacarcin Gene Cluster

The biologically active compound mensacarcin is produced by Streptomyces bottropensis. The cosmid cos2 contains a large part of the mensacarcin biosynthesis gene cluster. Heterologous expression of this cosmid in Streptomyces albus J1074 led to the production of the intermediate didesmethylmensacarcin (DDMM). In order to gain more insights into the biosynthesis, gene inactivation experiments were carried out by λ‐Red/ET‐mediated recombination, and the deletion mutants were introduced into the host S. albus. In total, 23 genes were inactivated. Analysis of the metabolic profiles of the mutant strains showed the complete collapse of DDMM biosynthesis, but upon overexpression of the SARP regulatory gene msnR1 in each mutant new intermediates were detected. The compounds were isolated, and their structures were elucidated. Based on the results the specific functions of several enzymes were determined, and a pathway for mensacarcin biosynthesis is proposed.     

INSIDIA 2.0 High-Throughput Analysis of 3D Cancer Models: Multiparametric Quantification of Graphene Quantum Dots Photothermal Therapy for Glioblastoma and Pancreatic Cancer

Cancer spheroids are in vitro 3D models that became crucial in nanomaterials science thanks to the possibility of performing high throughput screening of nanoparticles and combined nanoparticle-drug therapies on in vitro models. However, most of the current spheroid analysis methods involve manual steps. This is a time-consuming process and is extremely liable to the variability of individual operators. For this reason, rapid, user-friendly, ready-to-use, high-throughput image analysis software is necessary. In this work, we report the INSIDIA 2.0 macro, which offers researchers high-throughput and high content quantitative analysis of in vitro 3D cancer cell spheroids and allows advanced parametrization of the expanding and invading cancer cellular mass. INSIDIA has been implemented to provide in-depth morphologic analysis and has been used for the analysis of the effect of graphene quantum dots photothermal therapy on glioblastoma (U87) and pancreatic cancer (PANC-1) spheroids. Thanks to INSIDIA 2.0 analysis, two types of effects have been observed: In U87 spheroids, death is accompanied by a decrease in area of the entire spheroid, with a decrease in entropy due to the generation of a high uniform density spheroid core. On the other hand, PANC-1 spheroids’ death caused by nanoparticle photothermal disruption is accompanied with an overall increase in area and entropy due to the progressive loss of integrity and increase in variability of spheroid texture. We have summarized these effects in a quantitative parameter of spheroid disruption demonstrating that INSIDIA 2.0 multiparametric analysis can be used to quantify cell death in a non-invasive, fast, and high-throughput fashion.