安吉白茶的研究进展及发展前景

从安吉白茶的栽培种植历史、栽培技术措施、生化品质和返白机理四个方面对安吉白茶进行了详尽的阐述,提出了安吉白茶的发展现状和思路,为发展和引种安吉白茶提供理论参考。     

水生动物柱状黄杆菌的研究进展

柱状黄杆菌是柱形病的病原体,可感染全球的淡水鱼类。自然和养殖条件下的海水鱼类以及观赏鱼类也可感染发病。全世界每年由柱形病所造成的经济损失极其严重。文章回顾和总结了柱状黄杆菌的发现、病理变化、超微结构特点和血液学特征等方面的研究近况,对柱状黄杆菌的分离鉴定、柱形病的爆发条件及防治措施进行了概述,并提出了柱状黄杆菌研究的发展方向。     

柱状黄杆菌胶体金免疫层析快速检测方法的建立

为建立一种通过胶体金免疫层析技术快速检测柱状黄杆菌的方法,试验采用柠檬酸三钠还原法制备粒径为20 nm的胶体金颗粒,将其标记纯化的抗柱状黄杆菌单克隆抗体(McAb)制备出金标抗体结合垫。纯化的兔抗柱状黄杆菌多克隆抗体(PcAb)和羊抗鼠IgG分别包被在硝酸纤维素膜的检测线(T)与质控线(C)上,制备出胶体金免疫层析试纸条,并对试纸条的灵敏度、特异性及稳定性进行测定。结果显示,该试纸条检测灵敏度为1×10³ CFU,检测时间为3.5 min,制备的试纸条与迟钝爱德华氏菌、大肠杆菌、嗜水气单胞菌、鳗弧菌、溶藻弧菌、副溶血弧菌、哈维氏弧菌均无交叉反应,且稳定性好。本研究首次成功建立了柱状黄杆菌胶体金快速检测方法,所制备的试纸条具有灵敏、特异、稳定、快速等优点,可用于柱状黄杆菌的检测。     

抗柱状黄杆菌多克隆抗体的制备及其免疫学特性鉴定

为制备抗柱状黄杆菌多克隆抗体,本研究利用颗粒性抗原免疫新西兰白兔,收集的抗血清通过辛酸-硫酸铵法纯化,采用间接ELISA法检测纯化后多克隆抗体的效价和交叉反应性。结果显示,制备的多克隆抗体蛋白质浓度为29.28 mg/mL,效价在1:6.4×10⁴以上,与迟钝爱德华氏菌、大肠杆菌、嗜水气单胞菌、鳗弧菌、溶藻弧菌、副溶血弧菌及哈维氏弧菌等水生动物致病菌均无交叉反应。本研究成功建立了抗柱状黄杆菌多克隆抗体的制备方法,可用于柱状黄杆菌的快速检测。     

柱状黄杆菌弱毒株和车轮虫混合感染致金鱼烂鳃病的病原分析

【目的】确诊北京地区某养殖场金鱼发生烂鳃病的病原。【方法】采集具有临床症状的濒死金鱼,制作鳃组织的水浸片进行寄生虫和真菌观察,取肝脏、肾脏、脾脏、鳃组织开展金鱼造血器官坏死病病毒(GFHNV)检测。同时,从鳃上分离病原菌,分析病原菌的形态特征、理化特性、分类地位及药物敏感性等特性;采取鳃组织划痕浸泡和未划痕浸泡方式开展病原菌的人工感染试验。【结果】自然发病鱼鳃丝上有少量车轮虫寄生,未观察到真菌菌丝,GFHNV核酸检测呈阴性。从鳃组织分离到大量假根状菌落,该菌株为革兰染色阴性长杆菌,菌体大小(0.5～0.7)μm×(4～8)μm,氧化酶、过氧化氢酶阳性,降解明胶和硫酸软骨素,产生硫化氢,不发酵葡萄糖等糖醇类,基于16S rDNA序列构建的进化树与柱状黄杆菌聚为一枝,确认分离菌为柱状黄杆菌(Flavobacterium columnare),基因型Ⅰ型。划痕浸泡的各组金鱼均出现死亡,症状与自然发病鱼相似,划痕对照组和未划痕浸泡组均未出现死亡,经计算该菌对金鱼的半数致死量(LD₅₀)为8.8×10⁶ CFU,为弱毒株。该菌对恩诺沙星、盐酸多西环素和...     

黄鳝鱼脑膜炎脓毒性黄杆菌的分离与鉴定

１９９７年８月２２日,从广西凭祥市浦寨边贸点入境的越南黄鳝鱼２吨,随机取样１千克进行实验室检验,检出脑膜炎脓毒性黄杆菌（ＦｌａｖｏｂａｃｔｅｒｉｕｍｍｅｎｉｎｇｏｓｅｐｔｉｕｍＫｉｎｇ）,主要症状为头部肿、转圈、甚至发生昏迷,腹部出血、充血,有点状白...     

华西禽灵丹对巴氏杆菌的抑菌效果

用华西禽灵丹煎煮液对巴氏杆菌进行抑菌试验，结果显示，华西禽灵丹对巴氏杆菌的抑菌圈为２５．５ｍｍ，判为高度敏感。     

七种中草药对柱状屈挠杆菌和肠型点状产气单胞菌的体外抑菌试验

试验采用试管2倍稀释法对引起淡水鱼类细菌性烂鳃病和肠炎病的柱状屈挠杆菌和肠型点状产气单胞菌进行了大黄、黄芩等7种中草药的体外抑菌试验.结果表明7种中草药对这两种菌都具抑菌作用,MIC在7.8～250mg/ml之间.黄芩的抑菌效果最好,对肠型点状产气单胞菌MIC为7.8mg/ml;连翘抑菌效果较差.     

凝结芽孢杆菌抑菌特性的研究进展

凝结芽孢杆菌是近几年来我国开始逐渐研究的新型微生态制剂。相比于乳酸菌等益生菌,其不仅拥有与之类似的保健功效,同时拥有良好的耐高温,耐酸,耐胆盐等高抗逆性,并且对肠道致病菌有较佳的抑制力。本文主要针对凝结芽孢杆菌的抑菌特性、抑菌机制和应用状况进行了综述。     

警犬黄杆菌继发感染的诊断

1999年6～8月南京某犬场2～14月龄的犬相继发病,临床主要表现为体温升高,不食,粘液便、血便,流脓性鼻涕和眼屎,病程长的出现以后肢瘫痪为主的神经症状。根据流行病学、临床症状,结合包涵体检查初步诊断为犬瘟热。当病犬第2次体温升高则针对继发细菌感染进行抗感染治疗。在对病死犬进一步检查时,从其肺组织培养物中发现黄杆菌B群。经过同源动物回归试验和小白鼠经口感染试验,证实了该菌为本次疾病流行的继发性致病菌之一。现将诊断情况报道如下:1　临床症状　6～8月份正是南京地区梅雨季节,犬用颗粒饲料的保存条件较差,部分饲料出现霉变现象…     

In vitro antagonistic activities of Lactobacillus spp. against Brachyspira hyodysenteriae and Brachyspira pilosicoli

The sensitivity of Brachyspira hyodysenteriae and Brachyspira pilosicoli, respectively the causative agents of Swine Dysentery and Porcine Intestinal Spirochaetosis to two probiotic Lactobacillus strains, L. rhamnosus CNCM-I-3698 and L. farciminis CNCM-I-3699 was studied through viability, motility and coaggregation assays. The cell-free supernatant of these lactobacilli contains lactic acid, that is stressful for Brachyspira (leading to the formation of spherical bodies), and lethal. It was demonstrated for the first time the in vitro coaggregation properties of two probiotic Lactobacillus strains (active or heat-treated) with two pathogenic strains of Brachyspira, leading to (1) trapping of spirochaetal cells in a physical network as demonstrated by SEM; (2) inhibition of the motility of Brachyspira. Such in vitro studies should encourage in vivo studies in animal model to evaluate the potential of the use of probiotic lactobacilli through a feeding strategy for the prevention of B. hyodysenteriae and B. pilosicoli.     

In vitro antiviral activity of chestnut and quebracho woods extracts against avian reovirus and metapneumovirus

Field evidences have suggested that a natural extract, containing tannins, could be effective against poultry enteric viral infections. Moreover previous studies have shown that vegetable tannins can have antiviral activity against human viruses. Based on this knowledge three different Chestnut (Castanea spp.) wood extracts and one Quebracho (Schinopsis spp.) wood extract, all containing tannins and currently used in the animal feed industry, were tested for in vitro antiviral activity against avian reovirus (ARV) and avian metapneumovirus (AMPV). The MTT assay was used to evaluate the 50% cytotoxic compounds concentration (CC₅₀) on Vero cells. The antiviral properties were tested before and after the adsorption of the viruses to Vero cells. Antiviral activities were expressed as IC₅₀ (concentration required to inhibit 50% of viral cytopathic effect). CC₅₀s of tested compounds were >200 μg/ml. All compounds had an extracellular antiviral effect against both ARV and AMPV with IC₅₀ values ranging from 25 to 66 μg/ml. Quebracho extract had also evident intracellular anti-ARV activity (IC₅₀ 24 μg/ml). These preliminary results suggest that the examined vegetable extracts might be good candidates in the control of some avian virus infections. Nevertheless further in vivo experiments are required to confirm these findings.     

家养观赏地图鱼肺炎克雷伯氏菌、维氏气单胞菌与黏质沙雷氏菌的分离鉴定及耐药性分析

本试验旨在通过细菌分离鉴定,明确家养观赏地图鱼的死因,筛选敏感药物。采用常规方法分离纯化细菌后,进行细菌形态学观察,并通过小白鼠致病性试验、细菌主要生化鉴定、16SrDNA序列测定分析、药敏试验及耐药基因检测等方法对分离的细菌进行鉴定及耐药分析。分离出3株革兰氏阴性短杆菌,根据细菌形态特征及理化特性,结合16SrDNA序列测定与系统发育分析结果,判定其分别为肺炎克雷伯氏菌(Klebsiella pneumoniae)、维氏气单胞菌(Aeromonas veronii)和黏质沙雷氏菌(Serratia marcescens),其中肺炎克雷伯氏菌具有较强致病性。3株细菌均对洛美沙星、氧氟沙星、阿米卡星、卡那霉素敏感,对阿莫西林、氟苯尼考、克林霉素、甲硝唑等具有较强耐药性。结果表明,肺炎克雷伯氏菌、维氏气单胞菌、黏质沙雷氏菌的混合感染是家养观赏地图鱼的死亡原因。     

Acaricidal effects of the essential oil of Origanum minutiflorum (Lamiaceae) against Rhipicephalus turanicus (Acari: Ixodidae)

The acaricidal effects of the volatile essential oil Origanum minutiflorum O. Schwarz & P.H. Davis (Lamiaceae) against adult Rhipicephalus turanicus was evaluated at a variety of concentrations and exposure times. Generally tick mortality increased with concentration and exposure. Ticks exposed to vapors from cotton wicks containing at least 10 μl/L resulted in complete (100%) mortality at 120 min. The major constituent of essential oil obtained from the plant material of O. minutiflorum was carvacrol.     

Protection against Toxoplasma gondii brain cyst formation in mice immunized with Toxoplasma gondii cytoskeleton proteins and Lactobacillus casei as adjuvant

The aim of the study was to evaluate the protection generated in mice against Toxoplasma gondii brain cyst burden by vaccination with T. gondii cytoskeleton proteins using Lactobacillus casei as adjuvant. One hundred and sixty-eight NIH mice were randomly allocated into eight groups of 21 mice each. Animals were immunized as follows: in group 1 with Toxoplasma lysate antigen (TLA) in Freund's modified adjuvant, containing L. casei (FMA), in group 2 with Toxoplasma cytoskeleton proteins (TCPs) in FMA, in group 3 with FMA, in group 4 with phosphate buffered saline (PBS), in group 5 with L. casei dead by heath (Lc), in group 6 with Freund's complete adjuvant (FCA), in group 7 with TLA in FCA, and in group 8 with TCP in FCA. Mean brain cyst burden (±S.E.M.) was assessed in mice 8 weeks after challenge with T. gondii Me49 strain (20 cysts per mouse). The percentages of reduction in cyst burden per brain (P < 0.01) as compared with the group 4 (control: mean 3181 ± 97.5) were 77.25% (724 ± 98) in group 1, 88.02% (381 ± 97.5) in group 2, 38.92% (1943 ± 130.3) in group 3, 44.31% (1771.4 ± 102) in group 5, 59.28% (1295.2 ± 99.1) in group 7 and 55.69% (1409.5 ± 89.9) in group 8. In order of importance, the best protection was obtained in groups 2, 1, 7, 8, 5 and 3. Noticeably the mice inoculated with L. casei alone showed a significant reduction in T. gondii brain cysts (P < 0.01), while those animals treated with FCA alone did not. Additionally, IgM anti-T. gondii antibody levels, as determined by ELISA 2 weeks after challenge, were highest in group 2 (P < 0.01) than in the other seven groups. Results suggest that T. gondii cytoskeleton proteins with L. casei as adjuvant constitute a good anti-toxoplasmosis vaccine candidate.     

Phylogentic analysis of Anaplasma ovis strains isolated from sheep and goats using groEL and mps4 genes

Evidence of Anaplasma spp. in goats and sheep in Cyprus has been demonstrated by previous research. Herein, further research was performed for the identification of the exact Anaplasma spp. resulting in the identification of Anaplasma ovis strains in all samples examined. We used a bioinformatics as well as a molecular approach (study of groEl and mps4 genes) in order to verify the validity of the results. All samples depicted the presence of A. ovis regardless of the host (goat or sheep).     

The genome of Brucella melitensis

The genome of Brucella melitensis strain 16M was sequenced and contained 3,294,931 bp distributed over two circular chromosomes. Chromosome I was composed of 2,117,144 bp and chromosome II has 1,177,787 bp. A total of 3198 ORFs were predicted. The origins of replication of the chromosomes are similar to each other and to those of other α-proteobacteria. Housekeeping genes such as those that encode for DNA replication, protein synthesis, core metabolism, and cell-wall biosynthesis were found on both chromosomes. Genes encoding adhesins, invasins, and hemolysins were also identified.     

Seroprevalence of antibodies to Encephalitozoon cuniculi and Encephalitozoon intestinalis in humans and animals

The presence of antibodies against Encephalitozoon cuniculi (E. cuniculi) and Encephalitozoon intestinalis (E. intestinalis) was examined in 215 samples from humans and in 488 samples from five different species of domestic and companion animals in Slovakia. The 215 human samples and samples from 90 swine, 123 non-infected cattle (cattle), 24 cattle infected with bovine leukosis virus (BLV-positive cattle), 140 sheep and 111 dogs were examined by the enzyme-linked immunosorbent assay (ELISA). Samples with serum titres 1:200 or higher were considered as positive. Specific anti-E. cuniculi antibodies were found in humans (0.9%), swine (52%), cattle (2%), sheep (9%) and dogs (15%) except for the BLV-positive cattle at the titre of 1:200. The titre of 1:400 was detected only in humans (0.5%). The presence of specific anti-E. intestinalis antibodies at the titre of 1:200 was confirmed in humans (6%), swine (51%), cattle (11%), BLV-positive cattle (13%) and dogs (6%) but not in sheep. The anti-E. intestinalis antibodies reached the 1:400 in humans (1%), swine (4%) and BLV-positive cattle (17%). The presence of specific anti-E. intestinalis antibodies at the titre of 1:600 was observed only in one swine (1%). Significant differences were observed in animals at titres 1:200 and 1:400 (chi-squared test: p < 0.0001) for both pathogens and in humans only for E. cuniculi at the titre of 1:400 (chi-squared test: p < 0.0075).     

Anaplasma marginale infection in a Japanese Black cow 13 years after eradication of Rhipicephalus (Boophilus) microplus in Okinawa, Japan

In October 2007, a 15-year-old Japanese Black cow on Ishigaki Island, Okinawa, Japan, was diagnosed with Anaplasma marginale infection based on clinical symptoms, blood examination, smear observation, 16S rRNA and groEL gene sequence analysis, and the result of a CF test. The cow was introduced into the farm from mainland Japan as a calf in 1993, one year before the eradication of Rhipicephalus (Boophilus) microplus, the main vector of A. marginale in Okinawa Prefecture. It is possible that the cow was first infected with A. marginale as a calf in Ishigaki Island and had been persistently infected since then. This is the first reported clinical case of A. marginale infection of cattle since the eradication of R. microplus in Okinawa Prefecture. Additional analysis of major surface protein 1α amino acid sequences revealed that the A. marginale Okinawa strain presented four new repeat forms which were not seen in other strains. This indicates that the Okinawa strain may be a unique geographical variant of A. marginale.     

Protective immunity of recombinant Mycobacterium bovis BCG expressing rhomboid gene against Eimeria tenella challenge

Two recombinant Mycobacterium bovis BCG (rBCG) strains carrying the Eimeria tenella rhomboid gene (Rho) delivered by extrachromosomal vector pMV261 and integrative vector pMV361 were evaluated for their ability to protect chickens against E. tenella challenge. The chickens were immunized intranasal with BCG, rBCG pMV261-Rho, or rBCG pMV361-Rho twice at a 2-week interval. All the recombinant BCG immunized chickens developed specific immune responses, and there was a significant increases of the percentages of CD4⁺ and CD8⁺ cells compared to the control (P < 0.05). Challenge experiments demonstrated that the two rBCG strains could provide significant protection against E. tenella challenge. But vaccination with rBCG pMV261-Rho induced higher specific antibody titers and produced greater protection rate (56.04%) than rBCG pMV361-Rho group (P < 0.05). These results indicated that M. bovis BCG is a novel vaccine vector to express and present antigens of E. tenella, and rBCG has a potential as vaccine in chickens.