蟹源致病性拟态弧菌的粘附及侵袭特性

病原菌对机体的致病作用是由其产生的各种毒力因子共同作用的结果,其中病原菌对组织细胞或粘膜的表面粘附是造成机体感染的首要条件。病原菌的粘附因子主要包括菌毛粘附素和其它非菌毛粘附素(如鞭毛、外膜蛋白和血凝素等),其中以菌毛介导的病原菌对组织细胞的粘附是细菌在体内定居、增殖释放毒力因子发挥致病作用的关键。为了揭示拟态弧菌HX 4的致病机理,以经典粘附模式细胞HEp 2细胞作为体外细胞模型,探讨蟹源致病性拟态弧菌HX 4株的粘附特性以及受体物质和抗全菌抗体对细菌粘附作用的影响,同时采用庆大霉素清洗裂解培养法测定该菌对HEp 2细胞的侵袭力。结果显示,HX 4菌株能粘附HEp 2细胞,对HEp 2细胞具有侵袭力。细菌对HEp 2细胞的粘附方式为集聚性粘附,最佳粘附时间为1h,甘露糖和抗体能显著抑制该菌的粘附,表明HEp 2细胞上含有甘露糖样受体。该菌的粘附素除了主要是菌毛外,可能还含有鞭毛、外膜蛋白、血凝素等多种成分。     

乳酸菌及其代谢产物对鳗弧菌生长的抑制作用

鳗弧菌(Vibrio anguillarum)广泛分布于近海及河口海水环境,是导致多种海水鱼类疾病的重要的条件性病原菌之一,在世界范围内流行。控制鳗弧菌的数量和生长是防治鳗弧菌导致海水鱼类疾病的重要手段。抗生素的使用在防治弧菌病方面发挥了重要作用,但是由于细菌耐药性及抗生素残留等问题,抗生素的使用今后将受到限制。生物防治由于其特殊的优点正成为水产动物疾病防治的重要措施。乳酸菌是一类可以发酵糖类产生大量乳酸的细菌总称。它通过产生乳酸等有机酸、分泌乳酸菌素等代谢产物抑     

不同环境条件对溶藻弧菌粘附大黄鱼肠粘液的影响

研究了不同环境条件下溶藻弧菌对大黄鱼肠粘液的粘附作用。采用细菌计数法测定溶藻弧菌的粘附作用。粘附的细菌经SYBR GreenⅠ染色后在荧光显微镜下观察，用数码相机拍照后在电脑上计数。试验结果表明，溶藻弧菌对大黄鱼肠粘液的粘附量随菌浓度的升高而升高，并在1—1．5h内趋于饱和；粘附作用在15—30℃、pH偏酸时较强；盐度在5—35范围内对前肠粘液的粘附作用影响不明显，后肠粘液的粘附作用在此范围内随盐度增大而加强，在盐度为0时，溶藻弧菌对前、后肠粘液都无粘附作用；56℃热处理5min及60℃处理1h均能大幅减弱溶藻弧菌对两种肠粘液的粘附作用，表明溶藻弧菌表面的某些热敏结构在粘附作用中起着重要作用。根据以上结果，可以认为溶藻弧菌能够很好地粘附于大黄鱼肠粘液层，其粘附作用受温度、盐度、pH值等环境因子影响很大，溶藻弧菌表面的某些热敏结构可能在粘附过程中起着重要作用。研究结果表明，溶藻弧菌对大黄鱼肠粘液的粘附作用是可控制的，这对于鱼类养殖疾病的控制有一定的参考价值。     

光合细菌在水产养殖业中的应用

<正> 光合细菌是地球上出现最早的具有原始光能合成体系的生物,是一类在厌养条件下进行不放氧光合作用的细菌的通称。广泛分布于海洋、江河、湖泊、池塘等水域环境中,在自然界的物质循环过程中发挥着十分重要的作用。光合细菌个体小、繁殖快、适应性强、代谢方式多样,菌体细胞中含有丰富的营养成分,是一类极具开发潜力的有益微生物,在水产养殖业     

噬菌蛭弧菌、噬菌体和细菌素(三)

<正>3.3细菌素的化学组分及理化性质细菌素是一种具有生物活性蛋白质类物质。大多数细菌素是含有蛋白质和脂多糖的复合物多浆体,相当于菌体O抗原。细菌素抑制菌体的生长作用与蛋白质成分有关,在蛋白酶的作用下,可破坏其抑菌活性,其活性也与糖脂质有关。弧菌在pH1.3～12.5的范围内作用30min不受影响,56℃环境经5h或煮沸1min不被灭活。但是37℃、pH8.0的环境中与0.05%的胰蛋白酶接触20min,或100℃、10min可灭活。绿脓菌素在pH6.5～9.5环境中是稳定的,经蛋白酶作用,冻融或蒸镏水透     

“益生康”浓缩乳酸菌在水产养殖中的应用

正乳酸菌指发酵糖类主要产物为乳酸的一类无芽孢、革兰氏染色阳性细菌的总称,广泛存在于畜、禽肠道中。粪肠球菌是一种兼性厌氧的乳酸菌,是人和动物肠道内主要菌群之一,能产生天然抗生素,有利于机体健康。同时还能产生细菌素等抑菌物质,抑制大肠杆菌和沙门氏菌等病原菌的生长,改善肠道微环境。"益生康"是以粪肠球菌为主、辅以芽孢杆菌、酵母菌、反硝化细菌等有益微生物菌群发酵而成,在发酵时辅以生物多糖、蛋白质、氨基     

科技与学术动态

一项能防治虾病、降低养殖成本、提高产量和效益的光合细菌养虾新技术,已在日照市对虾养殖生产中被广泛推广应用。光合细菌是生活在水域中的一类种类繁多、有特殊功能的细菌。光合细菌和菌体含有丰富的蛋白质,是对虾的优质饵料;它能够利     

网箱养殖丁柱形病的诊治

<正>鱼类柱形病(Columnaris disease)是淡水鱼类养殖中的一类严重的细菌性疾病,该疾病分布广泛,曾有马鞍病、烂鳍病之称。对其病原的研究可以追溯到20世纪初,最早在密西西比河发现并命名,由于菌体为一种细长杆菌且能形成柱状堆积,将其命名为柱状芽孢杆菌(Bacillus columnaris)。随后,又经学者们多次分离不同鱼类柱形病的病原菌,将其命名为柱形粒球黏细菌(Chondrococcus columnaris)与柱状嗜纤维菌(Cytophaga columnaris)等。到20世     

光合细菌的特性及其在水产养殖上的应用

光合细菌是一类能够利用光能作为能源进行生长和繁殖的细菌的总称。它隶属于细菌门、真菌纲、红螺菌目。红螺菌目可分为二个亚目,三个科和十八个属。目前都已分离到纯种。当前在水产养殖业上使用的主要是红螺菌科的一类细菌。一、光合细菌的生态特性光合细菌主要生活在水田、浅的池塘、污浊的水体中。在氧气含量有限而光线能到达的沟渠、稻田以及鱼池的表层水、泥中,出现数量较多.可达105～107个菌体/mL。而在氧气充足的富营养化池塘和江河水体中却较少,但几乎所有的活性污泥中均可发现。由此可见,合适的光照、有限的供氧及丰富的有机营养成分,是光合细菌所赖以生存的生态环境所应具有的特性。     

中华鳖腐皮病的病原研究

从具有典型腐皮病症状的中华鳖体中分离到P—1、P—2两株细菌,经人工感染试验对健康鳖均产生了较强的致病力,出现与自然病鳖相同的症状,从而证实这两株菌株是中华鳖腐皮病的病原菌。经对菌体的形态特征、培养特性和生理生化反应进行鉴定,证明致病菌为嗜水气单胞菌。     

副溶血弧菌与肝素结合相关黏附蛋白的鉴定

黏附因子在病原菌的致病过程中发挥了重要作用,鉴定新的黏附因子是了解病原菌致病机制的重要手段。本研究中首次发现游离肝素能够竞争性抑制副溶血弧菌与Hela细胞的黏附,表明细胞外基质中的肝素可能是细菌重要的细胞表面黏附受体。进一步利用肝素亲和层析技术垂钓到6种副溶血弧菌的外膜蛋白,并通过基因克隆和原核表达技术成功获得重组的外膜蛋白并对其进行了深入研究。重组蛋白IMPDH、EF-Tu和Opp A可黏附Hela细胞,并可以显著抑制副溶血弧菌与Hela细胞的黏附,说明这3种蛋白可能是其重要的潜在黏附因子。     

Isolation and characterization of fish Aeromonas hydrophila adhesins important for in vitro epithelial cell invasion

The molecular mechanisms involved in the invasion of Aeromonas hydrophila (strain PPD 134/91) into host cells were studied in vitro using a carp epithelial cell line. Bacterial fractions were extracted with potassium thiocyanate (KSCN) to investigate the adhesins involved. Two groups of adhesins were found. The major group was high molecular weight proteins with the largest component being a 43-kDa protein. Amino terminal sequence analysis indicated that this may have been an outer membrane porin. This supports previous suggestions that a 43-kDa outer membrane protein may be important in adhesion of a human isolate of A. hydrophila . The minor group of adhesins were low molecular weight proteins likely to be less effective in mediating bacterial adhesion and invasion into carp epithelial cells.     

鱼精蛋白的抑菌机理

鱼精蛋白对细菌呼吸系统能产生微弱的抑制作用，但这并不是其抑菌活性的主要途径；鱼精蛋白主要是以分子中多聚精氨酸或多聚精氨酸与其它少数几个氨基酸以某一种结构或形式和细菌细胞壁结合，破坏细胞壁的形成，从而达到其抑菌效果。     

In-Pack Surface Pasteurization of Capture-Based,Pre-Rigor Filleted Atlantic Cod (Gadus morhua)

In this study, we targeted the surface bacteria of high quality vacuum-packed cod loins to investigate how this affected the shelf life. After heat processing, the storage temperature was kept at 4°C in order to mimic supermarket shelf conditions. Samples that had undergone minimal heating regimes were compared with control samples as well with samples that were heated into the core. Shelf life was assessed based on the findings of a sensory analysis and on microbial growth data and supported by measurements of liquid loss and pH. Surface pasteurization of these samples seems to prolong shelf life only to a limited degree, even for samples with a low initial contamination level. Transportation of some bacteria into the filet, possibly during the intense rigor mortis progress triggered by the heat process, may have created a general flux of water in the samples. Underneath the surface, these bacteria are exposed to a limited thermal load and very little microbial competition. Surface pasteurization is an efficient method to reduce microbial contamination of many foodstuffs. In the case of fresh fish, however, surface pasteurization seems to have a limited effect due to the structure of the muscle and the subsequent storage condition.     

中国对虾越冬期褐斑病的组织病理观察

由患不同程度褐斑病对虾的组织病理切片观察发现,各时期的褐斑病都包括甲壳及壳下内部组织两部分的病变;都有增生性和非增生性两种组织应答。故推论是由多种病原菌混合污染所致。在早期褐斑病虾之甲壳表面发现有粘液状分泌物,说明此时在对虾甲壳表面已有了局部免疫反应。     

Interaction of grammistins with lipids and their antibacterial activity

ABSTRACT: Grammistins are hemolytic and ichthyotoxic peptides in the skin secretion of soapfishes and are structurally characterized by their abundance in amphiphilic α-helicity. In the present study, their interaction with lipids and lipid vesicles as well as antibacterial activity were examined using four grammistins (Gs 1 and Gs 2 from Grammistes sexlineatus and Pp 1 and Pp 3 from Pogonoperca punctata ). The hemolytic activity of grammistins was inhibited by phospholipids but not by cholesterol. Moreover, grammistins released carboxyfluorescein entrapped within liposomes made of phosphatidylcholine. In contrast, grammistins were found to have antibacterial activity with a broad spectrum against nine species of bacteria, including both Gram-negative and Gram-positive groups. The potency of their antibacterial activity was not related to that of hemolytic activity, suggesting that grammistins bind to membrane phospholipids but lyse erythrocyte and bacterial membranes via different mechanisms. Conclusively, grammistins are new members of the family of cell non-selective membrane-lytic peptides with amphiphilic α-helices, being similar to pardaxins, which are secreted from the skin of soles, and to melittin, which is derived from bee venom.     

Using cell and developmental biology to enhance embryo survival in aquaculture

Research on how the young embryo protects itself from normal environmental stresses reveals that the earliest phases of development have unique, innate mechanisms to protect the embryo during this most sensitive phase of embryogenesis. This paper shows ways in which knowledge of these protection mechanisms might be used to advantage in the aquaculture situation. These include novel mechanisms to deter bacteria and fungi such as secretion of anti-bacterial/anti-fungal substances from the egg at fertilization, as well as the utilization of anti-fungal metabolites provided by symbiotic bacteria associated with egg cases. UV damage is avoided by provision of unique sunscreens to the embryos so that UV penetration into the cytoplasm is avoided. Finally, embryos have exaggerated mechanisms to avoid the effect of toxicants on development but these are inadequate to remove pollutants present in feed used in aquaculture. Approaches are suggested on how this knowledge about adaptations might be used in the aquaculture setting to avoid pathogens, increase UV resistance and reduce levels of pollutants.     

Pathology of bacterial gill disease: ultrastructure of branchial lesions

Abstract. The range of branchial lesions associated with bacterial gill disease (BGD) in rainbow trout, Oncorhynchus mykiss (Richardson), was investigated through the ultrastructural examination of 23 separate outbreaks of the disease condition within commercially reared stocks. Diseased branchial tissues had a large and diffusely distributed monomorphic population of filamentous bacteria which were strictly epicellular. Although bacterial colonization was restricted to the branchial cavity, it was neither site nor cell specific: epithelial and chloride cells of the lamellae, filaments and lining tissues of the branchial cavity were all uniformly affected. The bacteria possessed an extensive glycocalyx which appeared to facilitate adhesion to the apices of the microridged sub-unit modifications of the cell surface. Sites of colonization were accompanied by a diffuse pattern of cellular degeneration and necrosis that was generally restricted to the outer layers of epithelium. The polarity and nature of these changes suggest that the mechanism of interaction between the bacteria and host cells includes progressive hydropic change as a sequel to primary membrane damage and consequent increased cell permeability. These cellular changes were accompanied by the range of stereotypical responses of the gill to damage frequently reported for BGD including lamellar fusion, epithelial hyperplasia, and squamous and mucous cell metaplasia, in addition to lamellar spongiosis.     

冻融期刺参养殖池塘沉积物菌群结构特征及其影响因素

本研究以我国北方典型岸基半开放刺参(Apostichopus japonicus)养殖池塘为对象,利用高通量测序技术构建冻融期刺参养殖池塘沉积物菌群16S rRNA基因测序文库,解析封冰期、融冰期和化冰期刺参养殖池塘沉积物菌群结构特征,并查明影响菌群结构的主导环境因子。结果显示,冻融期刺参养殖池塘沉积物菌群丰度和多样性表现为整体下调趋势,在融冰初期呈现显著性波动(P<0.05)。冻融期刺参养殖池塘沉积物菌群结构呈现显著性差异,封冰期、融冰期和化冰期差异菌群分别隶属于厚壁菌门(Firmicutes)、酸杆菌门(Acidobacteria)和软壁菌门(Tenericutes)。尽管不同阶段微生物相对丰度比例不同,但第一优势菌门均隶属于变形菌门(Proteobacteria),相对丰度高于49.04%;次优势菌门则呈现出显著性变化,其中,封冰期为拟杆菌门(Bacteroidetes),融冰期为绿弯菌门(Chloroflexi)和放线菌门(Actinobacteria),化冰期为浮霉菌门(Planctomycetes)。环境因子与菌群相关性分析表明,冻融期刺参养殖池塘沉积物菌群结构与环境因子具有显著相关性(P<0.05),温度、盐度、总氮和总有机碳是沉积物菌群的主导环境因子。本研究将为刺参养殖池塘精细化管理提供理论依据。     

虾夷扇贝雄性生殖系统的组织学研究

１９９７年取材研究了大连长海县的虾夷扇贝的雄性生殖系统的组织结构。虾夷扇贝的精巢构造与栉孔扇贝,贻贝的相似,也是由外膜及其内的无数生殖小管构成。外膜含单层柱状上皮及较厚的肌层。生殖小管间充填着结缔组织及来自外膜的薄层肌肉,结缔组织中含有血管,神经及输精细管。生殖小管由位于基膜上的生殖上皮构成,生殖上皮不断向腔内增殖出精原细胞,初级精母细胞,精细胞及业郛。