南极放线菌菌株N-1抗菌活性物质的初步研究及其菌种鉴定

对一株从南极海泥样品中分离出的放线菌菌株N-1分泌的抗菌活性物质进行初步研究,并对该菌进行菌种鉴定。通过纸片法对其发酵液进行体外抗菌活性研究;将其发酵液调至不同pH用不同极性的有机溶剂萃取,研究该活性物质的酸碱性和极性;将调至不同pH值的发酵液按不同时间温度梯度做加热处理,研究该活性物质的稳定性;并通过形态学观察、培养特征、生理生化特征及16S rDNA分析方法对其进行系统发育分析和菌种鉴定。结果表明该菌株发酵液对耐青霉素G、苯唑西林、四环素、莫西沙星、氯洁霉素、红霉素等抗生素的葡萄球菌、无乳链球菌等有明显抗菌作用,其抗菌活性物质在酸性条件下有良好的热稳定性,碱性条件下易于被氯仿等有机溶剂萃取;菌种鉴定数据表明该菌归属于生金链霉菌(5treptomyces aureofaciens)。研究确定南极放线菌菌株N-1为生金链霉菌,其代谢产生的抗菌活性物质稳定性好,大部分为极性中等的弱碱性化合物,对多重耐药菌有良好的抑制作用,有很好的研发价值。     

农用抗真菌海洋微生物的筛选及放线菌T19-07活性代谢产物的初步研究

目的通过筛选获得具有拮抗植物病原真菌活性的海洋微生物菌株,并对其中一株海洋生境的结节链霉菌(Streptomyces nodosus)T19-07的活性代谢产物进行初步研究。方法以植物病原真菌为靶标,采用平板对峙培养法筛选出活性菌株;再以抑菌活性为指标,考察较强活性菌株T19-07在5L发酵罐中的培养过程特征,并通过大孔吸附树脂XAD-16柱层析对活性物质进行分离提取,结合TLC生物自显影和HPLC快速确定代谢产物中的活性组分。结果从31株海洋微生物中筛选出12株对多种植物病原真菌具有拮抗作用的菌株;确定了菌株T19-07的代谢产物中的主要抑菌活性物质,其相对分子质量为214,并且它对茄交链格孢霉的离体抑菌活性和已登记的化学农药异菌脲活性相当,MIC<12.5μg.mL-1。结论海洋微生物是寻找农用抗生素的重要资源,海洋放线菌T19-07产生的拮抗植物病原真菌物质具有较好的离体抑菌活性,具有进一步研究开发的潜力。     

FIM-0916菌株中代谢产物的抗菌活性及稳定性考察

目的：鉴定链霉菌Streptomyces sp.FIM-0916发酵液中的抗菌活性代谢产物并探讨其化合物的稳定性。方法采用大孔吸附柱层析、常压反相色谱、高效液相色谱等方法对FIM-0916菌株发酵液进行分离纯化,通过现代波谱分析对获得抗菌活性物质0916A进行鉴定,并考察其稳定性。结果从FIM-0916菌株发酵液中分离到1个环脂肽类化合物并具有相关抑菌活性,根据理化性质研究和波谱分析,证实该化合物与Amphomycin（安福霉素）同质,该化合物在在偏碱性水溶液、低温温度条件下稳定。结论从FIM-0916发酵液中分离得到环脂肽化合物0916A,与amphomycin同质,有机溶剂、pH、温度对0916A的稳定性具有重要影响。活性研究表明该化合物对革兰氏阳性菌如枯草芽孢杆菌、耐药金黄色葡萄球菌等具有明显的抑制活性。     

响应面法优化紫色链霉菌发酵液的发酵工艺及其抑菌活性研究

目的抗生素的滥用带来了很大的问题,分离并寻找新的具有抑菌活性的次生代谢产物的链霉菌是开发新型抗菌药物的主要手段。方法采用滤纸片法研究紫色链霉菌发酵液的抑菌活性,并通过响应面法优化其液体发酵产抑菌活性物质的发酵工艺。结果紫色链霉菌发酵液对细菌有较强的抑菌作用,而对真菌的抑菌作用较弱、对金黄色葡萄球菌的抑菌作用最强,对白色葡萄球菌和禽巴杆菌有较强的抑菌作用,对沙门菌、大肠埃希菌和中华根霉有较弱的抑菌作用,对枯草芽孢杆菌、铜绿假单胞菌和黑曲霉没有抑菌效果。经响应面法优化后,紫色链霉菌液体发酵的最优工艺参数为葡萄糖+可溶性淀粉20.23g/L、蛋白胨2.54g/L、NaCl 0.76g/L、K_2HPO_4 0.99g/L。结论在此条件下,紫色链霉菌发酵液的抑菌圈直径为19.63mm,比优化前提高了18.9%。本研究为筛选新的天然抗菌活性物质提供了一定的理论基础。     

土茯苓体外抗菌活性实验

目的用改良方法测定土茯苓水煎液对金黄色葡萄球菌等 8种细菌的抗菌活性。方法用K B法 (培养基为MH固体培养基 )测定抗菌活性 ;以液体稀释法及MH固体培养法测定最小抑菌浓度、最小杀菌浓度值及抑菌率。结果土茯苓水煎液对金黄色葡萄球菌、福氏痢疾杆菌、白喉杆菌、炭疽杆菌有极强的抑菌活性和很高的抑菌率 ;对大肠杆菌、溶血链球菌、绿浓杆菌、鼠伤寒沙门菌的抑菌活性稍弱。结论土茯苓水煎液具有较强的抗细菌活性及较宽的抗菌谱 ,作为抗细菌资源具有一定的利用价值     

海洋放线菌M324抑菌活性代谢产物的研究初报

M324是从中国江苏连云港沿海海泥中分离出的一株放线菌,能产生广谱抗菌活性物质.文章报道了对该菌株的分子生物学鉴定、其抑菌活性产物的粗提取和部分化学性质的研究结果.发现海洋放线菌M324为灰菌素链霉菌的一个新菌株.归属球孢哑群;抗菌物质具有强极性,易溶于水和二甲基亚砜,微溶于甲醇和乙醇.能够被弱极性大孔树脂所吸附,并能用低浓度甲醇溶液解吸;活性物质中有糖环结构,为一种中性糖苷类抗生素.     

海洋放线菌F1发酵条件优化及抑菌物质性质的初步研究

目的 对筛选出的海洋放线菌F1的发酵培养基及条件进行优化,并对菌株F1分泌的有活性的次级代谢产物的特性进行了初步研究。 方法 采用单因素实验和正交试验的方法对发酵培养基及发酵条件进行优化,观察pH值、温度、光照、紫外线、储藏温度对抑菌物质稳定性的影响,了解抑菌物质的极性及疏水特性。结果 优化的最佳培养基为：可溶性淀粉20.0 g,NaCl 1.0 g,胰蛋白胨 0.5 g,Yeast Extract 2.0 g,K2HPO4 ? 3H2O 0.5 g,MgSO4 ? 7H2O 0.5 g,FeSO4 ? 7H2O 0.01 g,陈海水1000 mL, pH7.4-7.6,固体培养基加1.5%的琼脂粉。摇瓶装量30％,接种量10％,发酵时间168 h时抑菌抑菌圈最大,抑菌物质有较好的热、光、紫外线及储藏温度稳定性,pH值在3～12有活性,在强酸环境中失活,耐碱不耐酸,活性物质溶于石油醚和乙酸乙酯,不溶于正丁醇。结论 通过优化实验确定了菌株F1最优发酵培养基及发酵条件,抑菌物质有较好的稳定性,有较大极性和水溶性。     

北极放线菌BF-1发酵条件优化及代谢产物抑菌活性研究

目的优化发酵工艺以提高北极放线菌BF-1发酵液中抑菌活性物质的产量;测定BF-1次级代谢产物的体外抑菌活性。方法以发酵液抑菌活性为指标,采用单因素实验和正交实验对放线菌BF-1发酵培养基和发酵条件进行优化;琼脂稀释法测定BF-1发酵液最低抑菌浓度。结果最佳发酵培养基:淀粉5g.L-1,NH4Cl 5g.L-1,黄豆15g.L-1,MgSO40.25g.L-1,海水晶30g.L-1;最佳发酵条件:28℃,起始pH7,接种量5%;BF-1发酵液对绿脓杆菌的最低抑菌浓度(MIC)为640μg.mL-1。结论北极放线菌BF-1发酵液中次级代谢产物具有显著的体外抑菌活性,优化后BF-1发酵液的抑菌活性与优化前相比提高了约2.6倍。     

环丙沙星在不同pH条件下的体外抗菌活性比较

目的:比较环丙沙星在5种不同pH条件下对受试菌的体外抗菌活性,为临床合理用药提供依据。方法:体外敏感试验采用微量稀释法,测定环丙沙星在各pH条件下对受试菌的最低抑菌浓度。结果:pH升高可降低环丙沙星对受试菌的最低抑菌浓度,其中以铜绿假单胞菌所受影响最大。结论:升高pH能增强受试菌对环丙沙星的敏感性。     

海洋小单孢菌FIM03-345产生的活性成分的初步研究

目的 研究海洋小单孢菌FIM 03-345所产生的抗菌活性物质.方法 以14种菌为供试菌,纸片法测定发酵液的抗菌谱;以枯草芽孢杆菌为指示菌检测活性.发酵产物采用有机溶媒提取、硅胶柱层析及HP20大孔吸附树脂柱层析等方法分离活性物质.结果 小单孢菌FIM03-345发酵上清液对枯草芽抱杆菌和变形杆菌有强的抑制作用;发酵上清液60℃水浴2h活性不变,温度升高到80℃时活性明显降低;发酵液在pH 2～8时活性无明显变化,在pH10～12时活性略下降;薄板层析结果表明该抗菌物质至少含有2个组分.结论 海洋小单抱菌FIM 03-345发酵液具有抗G+细菌活性.该活性物在酸性和中性下较稳定,在pH 10以上及温度80℃时活性下降.发酵液粗提物中A为主要活性组分.     

Studies on medium optimization for the production of antifungal and antibacterial antibiotics from a bioactive soil actinomycete

A microbial isolate, characterized as Streptomyces sp. (MTCC 6819), produced antifungal metabolite intracellularly and antibacterial metabolite extracellularly under submerged fermentation conditions. This Gram-positive bacterium showed broad antimicrobial activity spectra against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) of partially purified (68.4%) antibacterial metabolite ranged between 50 and 12.5 μg/mL against multiple-drug-resistant bacteria. The producer organism exhibited strong activity against various yeast and fungi. The MIC values of the partially purified (70%) antifungal metabolite ranged between 6.25 and 3.125 μg/mL for unicellular fungi and 12.5 and 6.25 μg/mL for filamentous fungi. The conditions for the production of these bioactive agents were optimized and the effects of various nutritional factors were studied by classical and statistical methods.     

1株发光杆菌Photorhabdus asymbiotica的次级代谢产物研究

摘要：目的 研究1株发光杆菌Photorhabdus asymbiotica抗革兰阴性菌的活性次级代谢产物。方法 以抗革兰阴性菌活性为导向,采用大孔吸附树脂、MCI柱色谱,以及反相高效液相色谱等多种分离纯化技术,利用HR-ESIMS和NMR等波谱学方法,分离Photorhabdus asymbiotica发酵液中的化合物并鉴定其结构。结果 从菌株Photorhabdus asymbiotica中获得3个次级代谢产物,并鉴定为darobactin(1)、环(L-色氨酸-L-脯氨酸)(2)和环(L-脯氨酸-L-苯丙氨酸)(3)。其中化合物1对大肠埃希菌、肺炎克雷伯菌和鲍曼不动杆菌均具有显著的抗菌活性。结论 化合物1为发光杆菌Photorhabdus asymbiotica中主要的抗革兰阴性菌活性化学成分。     

五味子对耐甲氧西林金黄色葡萄球菌体外抑菌活性部位的筛选和UPLC-QTOF-MS/MS分析活性组分化学成分

目的：研究五味子对耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus,MRSA）体外抑菌活性部位的筛选以及分析五味子活性组分化学成分。方法：采用系统溶剂法分段萃取和AB-8大孔吸附树脂分离技术,结合管碟法对各分离组分进行体外抗耐甲氧西林金黄色葡萄球菌活性追踪检测,筛选出五味子抑菌活性最强组分。超高效液相（UPLC）、电喷雾四级杆飞行时间质谱（ESI-QTOF-MS）和二级质谱（MS/MS）对五味子抑菌活性组分进行分析。结果：筛选出70%乙醇提取的五味子依次经乙酸乙酯萃取和AB-8大孔吸附树脂水洗脱的组分（EEW component）为抗MRSA体外抑菌活性部位,同时对抗生素敏感金黄色葡萄球菌和临床分离的耐药MRSA均具有较强的抑菌活性。UPLC-QTOF-MS/MS分析体外抑菌活性组分,根据一级质谱提供的相对分子质量和二级质谱高能量碰撞碎片信息,初步鉴定了11个化合物,这11个化合物分别为奎尼酸（1）、苹果酸（2）、柠檬酸（3）、苹果酸异构体（4）、咖啡酰奎尼酸（5）、莽草酸（6）、柠檬酸单甲酯（7）、原儿茶酸（8）、富马酸单乙酯（9）、2-羟基-丙基三羧酸-2-乙酯（10）和柠檬酸二甲酯（11）。结论：本实验初步筛选了五味子抑菌活性部位,为开发天然抑菌制剂提供了方法和思路。     

SIP系列大孔吸附树脂的性能及应用

大孔吸附树脂能从水溶液中有选择地吸附有机物质,它与离子交换法和溶媒法相比,具有许多独特的优点.本文介绍 SIP 系列大孔吸附树脂的性能、规格,并通过实例阐述其应用。     

Identification and characterization of a novel antimicrobial peptide compound produced by Bacillus megaterium strain isolated from oral microflora

In recent years, the decreased efficacy of existing antibiotics toward management of emergent drug-resistant strains has necessitated the search for novel antibiotics from natural products. In this regard, Bacillus sp is well known for producing variety of secondary metabolites of potential use. Therefore, we performed an investigation to isolate and identify Bacillus sp from oral cavity for production of novel antimicrobial compounds. We extracted, purified, and identified a novel bioactive compound by B. megaterium (KC246043.1). The optimal production of compound was observed on de Man Rogosa and Sharpe broth by incubating at 37?°C, and pH 7.0 for 4?days. The bioactive compound was extracted by using n-butanol (2:1 v/v), purified on TLC plates with detection at R_f 7.8?cm; further characterized and identified as a cyclic ploypeptide sharing structural similarity with bacitracin. Minimum inhibitory concentration of bioactive compound was found to be 0.25, 0.5, 1.0, 3.125 and 6.25?μg/ml against Micrococcus luteus ATCC10240, Salmonella typhi ATCC19430, Escherichia coli ATCC35218. Pseudomonas aeruginosa ATCC27853 and Staphylococcus aureus ATCC25923 respectively, with no activity against Candida albicans ATCC10231. Our findings have revealed a novel cyclic peptide compound from B. megaterium with broad spectrum antimicrobial activity against both Gram positive and Gram negative bacteria.     

Evaluation of microalgae and cyanobacteria as potential sources of antimicrobial compounds

In recent decades, marine microorganisms have become known for their ability to produce a wide variety of secondary bioactive metabolites. Several compounds have been isolated from marine microorganisms for the development of novel bioactives for the food and pharmaceutical industries. In this study, a number of microalgae were evaluated for their antimicrobial activity against gram-positive and gram-negative bacteria, including food and plant pathogens, using various extraction techniques and antimicrobial assays. Disc diffusion and spot-on-lawn assays were conducted to confirm the antimicrobial activity. To measure the potency of the extracts, minimum inhibition concentrations (MIultCs) were measured. Three microalgae, namely Isochrysis galbana, Scenedesmus sp. NT8c, and Chlorella sp. FN1, showed strong inhibitory activity preferentially against gram-positive bacteria. These microalgal species were then selected for further purification and analysis, leading to compound identification. By using a mixture of different chromatography techniques gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS), we were able to separate and identify the dominant compounds that are responsible for the inhibitory activity. Additionally, nuclear magnetic resonance (NMR) was used to confirm the presence of these compounds. The dominant compounds that were identified and purified in the extracts are linoleic acid, oleic acid, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). These compounds are the potential candidates that inhibit the growth of gram-positive bacteria. This indicates the potential use of microalgae and their antimicrobial compounds as biocontrol agents against food and plant pathogens.     

Effect of pH on metabolism of glycyrrhizin, glycyrrhetic acid and glycyrrhetic acid monoglucuronide by collected human intestinal flora

Collected human intestinal flora (whole bacteria) was incubated with glycyrrhizin (GL), glycyrrhetic acid (GA), glycyrrhetic acid monoglucuronide (GAMG) and a combination of the three for 10 min at 37 degrees C under pH 5.6 and 7.0. The effect of these components on GL beta-D-glucuronidase activity, GAMG beta-D-glucuronidase activity and metabolite production in whole bacteria was examined. GL and GA were not metabolized at pH 5.6 and 7.0 by whole bacteria, while the level of GAMG changed at both pH 5.6 and 7.0. However, preincubated whole bacteria converted GA and a combination containing GA to other metabolites removed 3alpha-hydroxyglycyrrhetic acid and 3-oxoglycyrrhetic acid. The level of GL beta-D-glucuronidase activity remaining in whole bacteria after exposure to both GA and GAMG was above its initial level at pH 5.6 and 7.0, and the level of GAMG beta-D-glucuronidase activity remaining after exposure to GL, GA and GAMG was suppressed against control at pH 5.6 and 7.0. It is found that intestinal bacteria had similar action against GL, GA and GAMG at between pH 5.6 and 7.0.     

西兰花总黄酮的制备及体外抗肿瘤活性研究

目的探讨西兰花总黄酮的抗肿瘤活性。方法新鲜西兰花花蕾晒干粉碎后,用超声辅助70%的乙醇提取其中黄酮类成分,然后采用AB-8型大孔吸附树脂进行纯化,利用紫外扫描光谱法进行定量鉴定;采用MTT方法检测纯化前后西兰花黄酮类化合物对SMMC-7721细胞的生长抑制作用。结果使用超声辅助乙醇提取法西兰花黄酮得率为0.1%,粗提物纯度为2.63%,大孔吸附树脂纯化后纯度为9.28%。结论纯化后的西兰花总黄酮对SMMC7721细胞生长的抑制作用随剂量增加而增强,呈剂量依赖性。西兰花总黄酮可显著抑制肝癌细胞株SMMC-7721的生长。     

大孔吸附树脂分离岩黄连总生物碱的研究

利用大孔吸附树脂分离岩黄连中的总生物碱,采用静态和动态吸附-解吸附方法,以总生物碱和脱氢卡维丁含量为指标,考察了6种大孔吸附树脂对岩黄连总生物碱的吸附能力,其中D101型大孔吸附树脂的比吸附量和比洗脱量均较高.优化后的提取上艺为:上样药液原药材浓度0.2g/ml,吸附流速为2BV/h,解吸附溶剂为60%乙醇(3BV),所得岩黄连提取物中总牛物碱含量人于60%.