北京地区鲤科鱼暴发性传染病的病原研究

本文报道了北京地区从自然患暴发性传染病的鲢、鳙、鲤等鱼体上分离到16个菌株,其中有8株菌致病力明显,特别是SC96-1-1和SC96-2-4等株菌,能使受试鱼感染显症和致死,仅需6～24 h,其发病率达100％。经对该菌进行形态、生理生化特性测定及分类鉴定后,确认该菌是一种革兰氏阴性菌,为具有运动力的短杆菌,有如下特点：氧化酶和V-P反应均呈阳性,发酵葡萄糖产酸、产气,发酵甘露醇,不发酵肌醇,不分解脲素。并证实北京地区暴发性传染病病原为嗜水产气单胞菌(Aeromonas hydrophila)。该结果为进一步防治北京地区鲤科鱼暴发性传染病提供了科学依据。     

生物群落多样性的测度方法VI：与多样性测度有关的统计问题

物种多样性测度是（群落的）总体参数,它们常常是未知的,需要通过抽样将它们估计出来,因此,必须了解估计量的抽样性质。本文对与一些多样性测度的均值、方差的估计和假设检验以及大、小样本分布等有关的问题作了综述。可以看出大多数多样性测度的抽样性质还不清楚,有些甚至根本就没有研究过。Ｐｉｅｌｏｕ的合并样方法和刀切法是两个比较通用的方法,用它们可以解决其中的一些问题。但相比之下,刀切法更实用。     

生物群落多样性的测度方法Ⅵ:与多样性测度有关的统计问题

物种多样性测度是(群落的)总体参数,它们常常是未知的,需要通过抽样将它们估计出来,因此,必须了解估计量的抽样性质.本文对与一些多样性测度的均值、方差的估计和假设检验以及大、小样本分布等有关的问题作了综述.可以看出大多数多样性测度的抽样性质还不清楚,有些甚至根本就没有研究过.Pielou的合并样方法和刀切法是两个比较通用的方法,用它们可以解决其中的一些问题.但相比之下,刀切法更实用.     

生物群落多样性的测度方法：Ⅰα多样性的测度方法（上）

生物群落多样性的测度方法Ⅰα多样性的测度方法（上）马克平（中国科学院植物研究所,北京１０００４４）１引言生物群落是在一定地理区域内,生活在同一环境下的不同种群的集合体,其内部存在着极为复杂的相互联系。由于功能整合原理,即系统的加合性或突生性（ｅｍｅｒ...     

生物群落多样性的测度方法：Ⅰα多样性的测度方法（下）

生物群落多样性的测度方法Ⅰα多样性的测度方法（下）马克平（中国科学院植物研究所,北京１０００４４）刘玉明（北京市教育学院,北京１０００４４）１物种多样性指数物种多度分布模型对群落的多样性数据进行了很好的描述。当观察到的数据较好地服从某一理论分布时,则...     

生物群落多样性的测度方法 V.生物群落物种数目的估计方法

群落的物种数目,即物种丰富度,是最古老、同时也是最基本的一个多样性概念,从对它的估计中可以得到关于物种灭绝速率方面的信息,这对生物多样性保护是非常重要的。已经提出了很多方法来估计群落中的物种数目,这些方法可以分为两大类,即基于理论抽样的方法和基于数据分析的方法。前者包括经典估计方法和贝叶斯估计方法;后者包括对数正态分布的积分方法、再抽样方法和种－面积曲线的外推方法。发现：（１）有些方法适用于动物群落,如大多数基于理论抽样的方法;有些方法则适用于植物群落,如大多数基于数据分析的方法;（２）这些方法还没有经过全面而系统地比较;（３）还没有一个普遍认为比较好的方法。因此,建议采用野外调查与模拟研究相结合的方法对各种估计方法进行系统地评价。     

生物群落多样性的测度方法Ⅲ与物种－多度分布模型有关的统计问题

生物群落多样性的测度方法Ⅲ与物种－多度分布模型有关的统计问题刘灿然，马克平（中国科学院植物研究所，北京１０００４４）周文能（中国农业科学院，北京１０００８１）在过去的几十年中，生态学家们对物种相对多度分布进行了广泛的研究，采用的方法主要有两种，即物种...     

嗜水气单胞菌感染现状及耐药分析

目的调查湖州市中心医院嗜水气单胞菌感染现状和耐药情况。方法采用常规方法分离,用VITEK-32全自动微生物分析仪进行菌种鉴定为嗜水气单胞菌或豚鼠气单胞菌,依据葡萄糖产气反应鉴定为嗜水气单胞菌。并根据配套药敏卡进行药敏试验。结果共分离到34株嗜水气单胞菌,主要来自痰液、胆汁、腹腔引流液或腹水。嗜水气单胞菌对哌拉西林、替卡西林、阿莫西彬克拉维酸、妥布霉素、头孢呋辛、头孢噻肟、头孢他啶、环丙沙星、复方新诺明耐药率为52．9％～73．5％。结论目前嗜水气单胞菌也呈现多重耐药现象,临床上应予以重视。     

Analysis of the interaction of Aeromonas caviae, A. hydrophila and A. sobria with mucins

Aeromonas species are known to be involved in human gastrointestinal diseases. These organisms colonize the gastrointestinal tract. Aeromonas hydrophila, A. caviae, and A. sobria have been demonstrated microscopically to adhere to animal cell lines that express mucous receptors, but quantitative studies of adherence to mucosal components such as mucin have not been published to date. Purified bovine submaxillary gland, hog gastric mucin, and fish skin mucin were used as a model to study mucin-binding activity among A. caviae, A. hydrophila, and A. sobria strains. Our findings revealed that binding of radiolabeled and enzyme-conjugated mucins to Aeromonas cells varied depending on the labeling procedure. The highest binding was observed when the three mucin preparations were labeled with horseradish peroxidase. Binding of the various horseradish peroxidase-labeled mucins by A. caviae, A. hydrophila, and A. sobria cells is a common property among Aeromonas species isolated from human infections, diseased fish, and from environmental sources. The proportion of Aeromonas strains which bind the various horseradish peroxidase-labeled mucins was significantly higher for A. hydrophila than for A. caviae and A. sobria. Bacterial cell-surface extracts containing active mucin-binding components recognized the horseradish peroxidase-labeled mucins. The molecular masses of the mucin-binding proteins were estimated by SDS-PAGE and Western blot as follows: A. caviae strain A4812 (95 and 44 kDa); A. hydrophila strain 48748 (97, 45, 33 and 22 kDa); and A. sobria strain 48739 (95 and 43 kDa). Mucin interaction with Aeromonas cells was also studied in terms of growth in mucin-rich media. The culture conditions greatly influence the expression of A. hydrophila mucin-binding activity.     

嗜水气单胞菌生物被膜对其耐药性的影响

建立了嗜水气单胞菌(Aeromonas hydrophila, Ah)的生物被膜(Bacterial biofilm, BF) 体外形成模型, 并对11种抗菌药物对BF细菌和浮游（Freecell, FC）细菌的清除作用进行了研究。将Ah J1株在放有硅胶膜的TSB中培养7d,用银染法鉴定,发现可形成良好的BF。FC细菌对青霉素具有耐药性, 最低杀菌浓度(MBC)为256μg/mL;对蒽诺沙星和氟哌酸最敏感,MBC分别为003μg/mL和0.25μg/mL。氟苯尼考对BF细菌的清除能力最强,作用于BF细菌和FC细菌的MBC之比为2∶1;卡那霉素、青霉素、新霉素的MBC比值在32∶1以上。扫描电镜观察蒽诺沙星作用于FC及BF细菌前后的形态变化,并测定其杀菌曲线。发现4×MBC时可完全清除FC细菌,但不能完全清除BF细菌;在32×MBC时,4h内可完全清除FC细菌,而24h内完全清除BF细菌。结果表明形成BF的Ah对抗菌药物可形成强耐受性,其潜在影响应引起足够重视。     

Dissection of the Yersinia enterocolitica virulence plasmid pYVO8 into an operating unit and virulence gene modules

Abstract Mesophilic Aeromonas hydrophila from serotypes O:11 and O:34 grown in a glucose-rich medium produce a capsule that can be seen under light and electron microscopy. The purified capsular polysaccharide has a composition qualitatively similar for strains O:11 and O:34, but quantitatively different. The capsular polysaccharides were immunogenic in rabbits, and did not cross-react with specific antibodies against either purified lipopolysaccharide from strains O:34 or O:11 or against the S-layer characteristic of strains from serotype O:11.     

嗜水气单胞菌溶血素基因的克隆表达及其类毒素的免疫原性分析

根据嗜水气单胞菌溶血素保护性抗原基因序列(GenBank Accession No. AF539467)设计一对引物, 以嗜水气单胞菌河北分离株基因组为模板, 经PCR扩增得到hly基因。序列分析表明, 该基因产物大小为1485 bp, 经测序与GenBank报道的多个嗜水气单胞菌hly基因序列一致性高于99%。将得到的hly基因定向克隆到原核表达载体pET-28a中构建原核重组质粒pET-28a- hly, 转化大肠杆菌 BL21(DE3)中, 得到重组菌株BL21(DE3)(pET-28a-hly), 经IPTG诱导后, SDS-PAGE分析可见一条56 kD的特异条带。Western blotting分析结果显示表达的Hly蛋白能与抗体发生特异性结合,说明其具有较好的免疫原性。将表达的溶血素蛋白制成类毒素疫苗免疫小鼠后, 具有较高的保护效力, 表明该类毒素疫苗有望作为预防由嗜水气单胞菌引起疾病的基因工程类毒素疫苗。     

Isolation and characterization of bacteriophage PM3 from Aeromonas hydrophila the bacterial receptor for which is the monopolar flagellum

PM3 is an Aeromonas-specific bacteriophage which was isolated and characterized on A. hydrophila strain TF7. Spontaneous mutants resistant to PM3 were non-motile having lost their characteristic monopolar flagellum. In addition, purified flagella inactivated PM3. PM3 is the first filamentous bacteriophage isolated on Aeromonas, the adsorption site for which is the monopolar flagellum.     

Ultrastructure of Red-Sore Lesions on Largemouth Bass (Micropterus salmoides): Association of the Ciliate Epistylis sp. and the Bacterium Aeromonas hydrophila*

SYNOPSIS. Epizootic outbreaks of red-sore disease in several reservoirs in the southeastern United States have been reported to cause heavy mortality among several species of fish having sport and commercial value. The etiologic agent is said to be the peritrich ciliate Epistylis sp.; secondary infection by the gram-negative bacterium Aeromonas hydrophila produces hemorrhagic septicemia which results in death. However, in recent studies on the largemouth bass Micropterus salmoides, Epistylis sp. could be isolated from only 35% of 114 lesions from 114 fish, while A. hydrophila was found in 96% of the same lesions. Transmission and scanning electron microscopy of lesions associated with red-sore disease indicate that neither the stalk nor the attachment structure of Epistylis sp. have organelles capable of producing lytic enzymes. Since other investigators have shown that A. hydrophila produces strong lytic toxins, and in absence of evidence to the contrary, it is concluded that Epistylis sp. is a benign ectocommensal and that A. hydrophila is the primary etiologic agent of red-sore disease.     

山姜素对鱼源耐药性嗜水气单胞菌体外抗菌作用的研究

旨为探究山姜素对耐药性嗜水气单胞菌的体外抑菌效果及其作用机制.通过测定山姜素对嗜水气单胞菌生长、细菌形态、电导率、乳酸脱氢酶(LDH)、蛋白质代谢和DNA的影响,研究山姜素对耐药性嗜水气单胞菌的抑菌机制.山姜素对5株鱼源耐药性嗜水气单胞菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为128-256μg/mL和5...