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。     

湘中地区安吉白茶病虫害防控技术

对湘中地区茶园安吉白茶主要病虫害进行调查,通过农业防治、物理防治、化学防治等措施为茶树病虫害防控提供减药控害技术支撑,提高茶叶产品竞争力,保障茶叶质量安全,促进茶产业的可持续发展.     

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.     

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…     

Rearing unit-level factors associated with bacterial gill disease treatment in two Ontario, Canada government salmonid hatcheries

Early-rearing salmonids in Ontario Ministry of Natural Resources (OMNR) fish hatcheries have been consistently affected by bacterial gill disease (BGD) (causative agent: Flavobacterium branchiophilum) for many years. Separate retrospective epidemiological investigations of BGD treatments at two OMNR fish hatcheries (Hatcheries A and B) for the 1999 production year were conducted using on-site hatchery records. Both investigations were carried out at the rearing unit-level, with early-rearing (<9 months of age) “tank-lot” as the unit of analysis to identify unique fish populations over time. Multivariable repeated measures logistic regression models were created for both hatchery datasets, controlling for lot-level and species effects. For Hatchery A, the species brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were significantly associated with BGD treatment, as well as lower water exchange rate, and higher feeding and mortality percentages during the 2 weeks previous to BGD treatment. At Hatchery B, the species brook trout (S. fontinalis) and splake (Salvelinus namaycush × S. fontinalis) were significantly associated with BGD treatment, as well as lower individual fish weights and treatment for BGD during the previous week. These results emphasize the importance of water quality, feeding rate, fish size and prior mortality on the development of BGD. Significant hatchery and species effects were evident, and future observational research on BGD must account for these factors in their design and analysis.     

Identification of Rickettsia felis in fleas but not ticks on stray cats and dogs and the evidence of Rickettsia rhipicephali only in adult stage of Rhipicephalus sanguineus and Rhipicephalus haemaphysaloides

Rickettsia spp. are zoonotic pathogens and mainly transmitted by various arthropod vectors, such as fleas, ticks, and lice. Previous epidemiological studies indicated that ectoparasites infested on dogs or cats may be infected by Rickettsia spp., and transmit them to human beings accidentally. In this study, the prevalence of Rickettsia infection was evaluated using fleas and ticks from stray dogs and cats in Taiwan. A total of 158 pools made by 451 cat fleas (Ctenocephalides felis) from 37 dogs and 4 cats were used for analysis. Besides, 386 Rhipicephalus ticks collected from the other 62 stray dogs were included in this study. Nymphal and adult ticks were individually analyzed but larvae were separated into 21 pools for molecular detection. Partial sequencing analysis of the gltA gene was applied for Rickettsia identification. The results showed that 44.3% (70/158) of the cat flea pools were harboring Rickettsia DNA. Although 6.9% (13/187) of adult ticks were infected with Rickettsia, neither larval pools nor nymphal ticks were found to contain Rickettsia DNA. According to the results of sequencing analyses, all Rickettsia PCR-positive cat flea pools were infected with R. felis, and all Rickettsia PCR-positive adult ticks were infected with R. rhipicephali. The results of this study demonstrated that C. felis but not Rhipicephlus sanguineus (the brown dog tick) and Rh. haemaphysaloides collected from stray animals in Taiwan could be infected the zoonotic pathogen R. felis. Moreover, R. rhipicephali was only identified in adult stage of Rhipicephalus sanguineus and Rh. haemaphysaloides.     

RNAi suppression of zebrafish peptidoglycan recognition protein 6 (zfPGRP6) mediated differentially expressed genes involved in Toll-like receptor signaling pathway and caused increased susceptibility to Flavobacterium columnare

In Drosophila, Toll signaling cascade, which resembles the mammalian Toll-like receptor (TLR)/IL-1R signaling pathways and regulates the expression of anti-microbial peptide genes, mainly relies on peptidoglycan recognition proteins (PGRPs) for the detection of bacterial pathogens. To explore the effect of zebrafish peptidoglycan recognition protein 6 (zfPGRP6) on Toll-like receptor signaling pathway, RNA interference (siRNA) and real time quantitative PCR (RQ-PCR) methods were used to identify differentially expressed genes regulated by zfPGRP6. The target genes included TLR2, TLR3, TLR5, TLR7, TLR8, IL1R, Sterile-alpha and Armadillo motif containing protein (SARM), myeloid differentiation factor 88 (MyD88) and nuclear factor (NF)-kappa B2 (p100/p52). The results of RQ-PCR showed that RNAi-mediated suppression of zfPGRP6 significantly down-regulated the expression of TLR2, TLR5, IL1R, SARM, MyD88 and p100/p52. The expression of beta-defensin-1 was also down-regulated in those embryos silenced by zfPGRP6. In challenge experiments to determine the anti-bacterial response to Gram-negative bacteria, RNAi knock-down of zfPGRP6 markedly increased susceptibility to Flavobacterium columnare.     

Seeking a niche: putative contributions of the hfq and bacA gene products to the successful adaptation of the brucellae to their intracellular home

Long-term residence of the brucellae in the phagosomal compartment of host macrophages is essential to their ability to produce disease in both natural and experimental hosts. Correspondingly, the Brucella spp. appear to be well adapted to resist the multiple environmental stresses they encounter in their intracellular home. This brief review will focus on the contributions of the hfq and bacA gene products to this adaptation. Studies with Brucella hfq mutants suggest that stationary phase physiology is critical for successful long-term residence in host macrophages. Analysis of Brucella bacA mutants, on the other hand, reveal very striking parallels between the strategies employed by the rhizobia to establish and maintain protracted intracellular residence in their plant host and those used by the brucellae during their long-term survival in the phagosomal compartment of host macrophages.