病原中的活性氧释放研究进展

活性氧的释放在动植物-病原菌互作过程中有着非常重要的作用.一般认为互作中的活性氧来源于动植物细胞生物膜中的氧化还原体系.但近年来随着互作研究的深入,发现动植物病原菌自身也有活性氧的释放以及复杂的调控系统,它们的活性氧释放能力很有可能与其致病性有一定的联系,并可能参与了互作,这些发现对深入了解动植物-病原菌的互作机制具有重要意义.概述了在细菌、真菌等多种动物病原菌中存在的活性氧释放现象,这些微生物活性氧产生的位点、相关功能分子以及调控机制,介绍了目前研究仍然较少但其潜在意义重大的植物病原菌中的活性氧释放现象、可能的调节机制和病理学意义.     

半边旗和阴地蕨粗多糖抗鱼病病原菌活性初步研究

采用4种方法提取阴地蕨和半边旗多糖,并利用圆形纸片法进行抑菌实验。结果表明:阴地蕨和半边旗多糖提取物显示出不同程度的抑制3种鱼病病原菌的活性,阴地蕨多糖提取物对肠炎病病原菌的最小抑菌浓度为6.25mg/ml。     

杜仲内生真菌DZJ03发酵液生物活性的研究

测定处于不同生长期的杜仲内生真菌DZJ03胞外多糖含量、发酵液中3种核苷含量,并对其菌株发酵液抑菌效果进行了研究,按50μg/mL的浓度测定了发酵液的石油醚、乙酸乙酯和甲醇等3种提取物对水稻恶苗病菌、棉花枯萎病菌2种植物病原菌以及烟草青枯病菌、金黄色葡萄球菌的抑制活性。结果表明:内生真菌DZJ03胞外多糖含量最高可达到2.0410g/L,其发酵液中所含腺苷、尿苷以及鸟苷的含量分别为1.2647 mg/g、0.8586 mg/g、1.0493 mg/g;发酵液乙酸乙酯相具有较强的抑菌活性,其对水稻恶苗病菌的抑制率为71.92%,抗烟草青枯病菌的抑菌圈直径达到19.21 mm。     

不同种类石韦的总多糖含量分析

对不同品种石韦的总多糖含量进行比较分析。取9种石韦经脱脂、除杂、超声水提、除蛋白、脱色、离心等得到总多糖溶液,再采用苯酚-硫酸法,以葡萄糖为对照品,在490nm处测定多糖的含量。结果显示,不同品种石韦多糖含量不同,庐山石韦总多糖含量最高,有柄石韦和石韦含量次之,西南石韦含量最少,其他品种石韦含量不高但相差不大。     

鲎G因子实验法定量测定药用、食用蘑菇多糖中的(1,3)-β-葡聚糖含量

(1,3)--葡聚糖是蘑菇免疫调节和抗肿瘤多糖的核心结构。通过鲎的G因子法测定了从19种药用和食用蘑菇中提取的27个多糖样品中(1,3)--葡聚糖的含量,我们发现(1,3)--葡聚糖普遍存在于这些蘑菇多糖提取物中。但是,(1,3)--葡聚糖的含量随蘑菇的种类和多糖提取的部位不同有着很大的差异,平均值大约占多糖的34.8%。从香菇、裂褶菌、云芝、草菇、灰树花、鸡腿菇和姬菇中提取的9种多糖中(1,3)--葡聚糖含量远高于其余的多糖。适当的纯化可以提高蘑菇多糖中(1,3)--葡聚糖的含量。我们的研究表明鲎G因子法可以用来快速有效地测定蘑菇多糖提取物中的(1,3)--葡聚糖含量。     

陕西省烟草灰霉病病原及云芝多糖对其防治研究

采用形态学观察和分子鉴定方法对2011年在陕西省发生的一种烟草未知病害的病原菌进行鉴定。从病叶组织分离纯化得到病原菌,通过致病性测定以及人工接种后再分离病菌,证明编号LJL007的菌株为该病的致病菌。依据病原菌的形态学和培养特征,将菌株LJL007鉴定为灰葡萄孢Botrytis cinerea Pers.,其有性型为富氏葡萄孢盘菌Botryotinia fuckeliana Whetzel。通过核糖体DNAITS序列分析,分离菌株LJL007序列(登录号:HM17900)与富氏葡萄孢盘菌序列(登录号:HM849615)同源性达100%,进一步证明该病原菌是灰葡萄孢Botrytis cinerea。云芝多糖在离体条件下,对灰葡萄孢的菌丝生长和孢子萌发均无直接抑制作用。云芝多糖对烟草灰霉病有较好预防保护作用,其预防效果可达56.29%。云芝多糖可显著提高烟草体内几丁质酶和β-1,3-葡聚糖酶活性,其活性峰值分别比对照提高56.89%和429.83%,说明云芝多糖可诱导植物产生抗病性。     

鲎G因子实验法定量测定药用、食用蘑菇多糖中的（1，3）-β-葡聚糖含量

(1,3)-β-葡聚糖是蘑菇免疫调节和抗肿瘤多糖的核心结构。通过鲎的G因子法测定了从19种药用和食用蘑菇中提取的27个多糖样品中(1,3)-β-葡聚糖的含量,我们发现(1,3)-β-葡聚糖普遍存在于这些蘑菇多糖提取物中。但是,(1,3)-β-葡聚糖的含量随蘑菇的种类和多糖提取的部位不同有着很大的差异,平均值大约占多糖的34．8％。从香菇、裂褶菌、云芝、草菇、灰树花、鸡腿菇和姬菇中提取的9种多糖中(1,3)-β-葡聚糖含量远高于其余的多糖。适当的纯化可以提高蘑菇多糖中(1,3)-β-葡聚糖的含量。我们的研究表明鲎G因子法可以用来快速有效地测定蘑菇多糖提取物中的(1,3)-β-葡聚糖含量。     

富硒灵芝菌丝多糖、蛋白的提取及其体外抗氧化和抗肿瘤活性研究

灵芝具有较强的硒富集能力，其中的硒元素多以硒多糖、硒蛋白等有机硒形式存在。本研究以灵芝菌丝为研究对象，采用不同方法提取菌丝多糖及菌丝蛋白，探究外源施硒对二者的含量及其抗氧化活性的影响，并初步探究了水提多糖和可溶性蛋白的抗肿瘤活性。结果表明，以硒含量为95μg/mL的培养基发酵得到的菌丝体，其可溶性蛋白及硒含量较高，分别为1.630 8 mg/g和36.905 7μg/g;采用超声辅助碱提法时，多糖含量较高，为32.070 9 mg/g,且该多糖的硒含量为33.864μg/g。与对照组相比，富硒组灵芝菌丝体其多糖和蛋白的抗氧化性较强，且均表现出浓度依赖性。此外，富硒灵芝菌丝体其硒多糖对肿瘤细胞的抑制增殖效果较好，对HCCLM、A549和HSC-3肿瘤细胞的IC₅₀值分别为3.765、3.23和2.267 mg/mL;但其硒蛋白对上述三种癌细胞的增殖抑制效果较差，其IC₅₀值分别为636.987、506.97、555.598μg/mL。     

红景天根中总黄酮和多糖的微波提取及含量分析

目的;从红景天中提取有效成分总黄酮,多糖,并测定其含量。方法：分光光度法,结果：测得红景天总黄酮含量4．62％,平均回收率为98．59％,RSD1．23（n=3),多糖含量9．12％,平均回收率为99．25％,RSD1．12％（n=3)。结论：运用微波技术辅助测定红景天中总黄酮和多糖的含量,反应速度加快,收率提高。     

甜菜渣中多糖的分析

近年来,发现动植物蛋白、酶、核酸、多糖组成的生物大分子具有多种多样的生理活性,特别是在免疫、抗肿瘤、抗病毒和心血管疾病的防治方面引起了国内外学者的关注。因此,对植物的有效成分的研究开始活跃起来。本文以甜菜渣中多糖成分含量进行了分析,结果如下: 采自制糖后的甜菜渣为原料,提取甜菜渣     

小桐子枝叶提取物对植物病原真菌的生物活性

采用菌丝生长抑制法,测定了小桐子枝叶6种不同溶剂提取物对小麦赤霉病菌、稻瘟病菌、烟草疫霉菌和辣椒疫霉菌的抑制作用,从中筛选出抑制作用最强的粗提物进行进一步的活性组分分离和抑菌活性测定。结果表明小桐子枝叶的乙醇提取物对4种植物病原菌抑制活性最高,在浓度为0.8 g·L^-1时,小桐子枝叶的乙醇提取物对小麦赤霉病菌、稻瘟病菌、烟草疫霉菌、辣椒疫霉菌菌丝生长抑制率分别为：87.1%、90.3%、86.4%、77.9%,其抗菌活性与农药世高均无显著差异;在小桐子枝叶乙醇提取物的不同溶剂萃取物对稻瘟病菌和烟草疫霉病菌进行生物活性追踪测试中发现,石油醚和水萃取物都具有较好的活性,当浓度为0.8 g·L^-1时,石油醚和水萃取物对两种病菌抑制率都达50%以上。表明小桐子枝叶含有丰富的抗植物病原真菌活性物质,且主要存在于小桐子枝叶乙醇提取物的石油醚相和水相中。     

Antibacterial potentiality of Argemone mexicana solvent extracts against some pathogenic bacteria

The sensitivity of two Gram positive (Staphylococcus aureus and Bacillus subtilis) and two Gram negative (Escherichia coli and Pseudomonas aeruginosa) pathogenic multi-drug resistant bacteria was tested against the crude extracts (cold aqueous, hot aqueous, and methanol extracts) of leaves and seeds of Argemone mexicana L. (Papaveraceae) by agar well diffusion method. Though all the extracts were found effective, yet the methanol extract showed maximum inhibition against the test microorganisms followed by hot aqueous extract and cold aqueous extract.     

金银花和苦丁茶多糖提取物抗菌活性研究

从金银花和苦丁茶中提取水溶性多糖,利用圆形纸片法对7种常见的食品腐败菌进行抗菌试验。结果表明:金银花和苦丁茶多糖提取物都具有一定程度的抗细菌与抗真菌活性,抗细菌活性比抗真菌活性强;苦丁茶多糖提取物对金黄色葡萄球菌的最低抑菌浓度为5mg/ml。     

Antimicrobial activity of the resins obtained from the roots and stems of Cedrus libani and Abies cilicica

The antimicrobial activity of the ethanol extract of resins obtained from the roots and stems of Cedrus libani and Abies cilicica was investigated using a disc diffusion method. Results revealed that crude extracts of the resins of both plants are highly effective against tested microorganisms by preventing their growth to a greater extent.     

Environmental and spatial drivers of beta diversity components of chironomid metacommunities in contrasting freshwater systems

Marine sponges are exposed to predation as well as to a wide array of potentially harmful microorganisms, and therefore they often possess chemical activity against putative predators and/or pathogens. Some crude extracts from sponges are effective in avoiding microbial colonization or potential infections, and in protecting them against predation. Here, the antibacterial activity of 18 sponge species of Antarctic shallow-waters was tested against four Antarctic and four human pathogenic bacteria. Moreover, all sponge extracts were tested for feeding repellence against the seastar Odontaster validus, one of the main predators living in those habitats. All the sponges showed antibacterial activity against at least one bacterial isolate, although not all of them were active against pathogenic bacteria. The antibacterial effect against sympatric bacteria was stronger than to pathogenic bacteria. In contrast, feeding deterrence was low, with similar activities in both hydrophilic and lipophilic extracts. Only four sponges (Myxilla lyssostyla, Phorbas areolatus, Polymastia invaginata and Iophon sp.), presented repellent chemical defenses. Therefore, we conclude that chemical defenses are widespread in Antarctic shallow-water sponges, and in fact, these sponges are better protected against bacteria than against the seastar predator. We conclude that Antarctic sponges represent a valuable source of biological active compounds with pharmacological and potential ecological relevance.     

水产品病原菌及其检测与控制技术研究进展

病原微生物一直以来是影响水产品质量安全的重要因素, 本文阐述了当前水产品中存在的主要病原微生物及其污染现状, 介绍了病原微生物快速检测新技术的研究进展, 并就如何控制水产品中病原微生物的污染, 提出预防措施和建议。     

Natural products of Alternaria sp., an endophytic fungus isolated from Salvadora persica from Saudi Arabia

This study is to evaluate the potential of endophytic fungi of Salvadora persica for the production of bioactive compounds against pathogenic bacteria and fungi. Forty-two fungal isolates were obtained from 135 young and old stem and 125 root segments. Those 42 isolates representing ten fungi include: Trichoderma sp. (the most common), two species of Alternaria, Rhizopus arrhizus and 6 sterile mycelia. The ten fungi were grown in liquid culture and their crude extracts were tested against pathogenic bacteria and fungi. Nine crude extracts gave positive reactions against pathogenic bacteria of which Alternaria sp. (A8) was chosen further study. The fungal isolate was growing as sterile mycelium and was identified by phylogenetic analyses based on LSU rDNA sequence data and it might represent undescribed species of Alternaria. Sixty-two bioactive chemical compounds were identified from the ethyl acetate crude extracts of Alternaria sp., of which the following were recorded as major compounds in the active sub-fractions. These compounds showed strong antibacterial activity in combination.     

Inhibition of the development of microorganisms (bacteria and fungi) by extracts of marine algae from Brittany, France

The inhibitory effects of aqueous, ethanolic and dichloromethane fractions from 16 marine algae from the Atlantic shores of North-East Brittany, France, have been investigated against microorganisms frequently associated with immersed surfaces. The extracts were tested in vitro against isolates of marine fungi, bacteria and yeasts potentially involved at different stages in the formation of biofilms in the sea. The high levels of inhibitory activity of nine extracts against marine fungi and Gram-positive bacteria and their apparent absence of toxicity against larvae of oysters and sea urchins suggests a potential for novel active ingredients. Received: 30 December 1998 / Received revision: 25 April 2000 / Accepted: 1 May 2000     

六种藜科植物提取物对植物病原菌的抑制活性

研究了角果藜（ Ceratocarpus arenarius）、盐穗木（ Halostachys caspica）、里海盐爪爪（ Kalidium caspicum） 、叉毛蓬（ Petrosimonia sibirica ）、盐角草（ Salicornia europaea ）和小叶碱蓬 （ Suaeda microphylla ）等六种新疆藜科植物提取物及其不同极性萃取部分对根癌土壤杆菌（Agrobacterium tumefaciens ）、黄瓜角斑病菌（P Pseudomonas lachrymarts）、番茄疮痂病菌（ Xanthomonas vesicatoria ） 等植物病原细菌以及杨树溃疡病菌（ Botryosphaeria dothidea ）、棉花枯萎病菌（Fusarium oxysporum f. sp. vasinfectum ）、稻纹枯病菌（Rhizoctonia solani）等病原真菌的抑制活性。结果显示角果藜、叉毛蓬和盐角草乙醇粗提物表现出一定抗细菌活性,其中以叉毛蓬和盐角草提取物对黄瓜角斑病菌的抑制活性最强。多数植物提取物及其不同极性萃取部分对杨树溃疡病菌表现出强的抑制活性。抗真菌活性成分主要存在于供试植物的石油醚、氯仿和正丁醇萃取部分中,提示活性成分为极性中等的化合物。角果藜和盐角草乙醇粗提物及其不同极性萃取部分对供试真菌有较好的抑制活性。     

Screening of Brazilian basidiomycetes for antimicrobial activity

A total of 103 isolates of basidiomycetes, representing 84 species from different Brazilian ecosystems, were evaluated for their antifungal and antibacterial activity in a panel of pathogenic and non-pathogenic microorganisms. Tissue plugs of the fruiting bodies were cultivated in liquid media and the whole culture extracted with ethyl acetate. Crude extracts from Agaricus cf. nigrecentulus, Agrocybe perfecta, Climacodon pulcherrimus, Gloeoporus thelephoroides, Hexagonia hydnoides, Irpex lacteus, Leucoagaricus cf. cinereus, Marasmius cf. bellus, Marasmius sp., Nothopanus hygrophanus, Oudemansiella canarii, Pycnoporus sanguineus, Phellinus sp., and Tyromyces duracinus presented significant activity against one or more of the target microorganisms. Eight isolates were active only against bacteria while three inhibited exclusively the growth of fungi. Two extracts presented wide antimicrobial spectrum and were active against both fungi and bacteria. Differences in the bioactivity of extracts obtained from isolates from the same species were observed.