副溶血弧菌海产品和临床分离株的表型及溶血素相关基因分析

副溶血弧菌是(Vibrio parahaemolyticus)常见的食源性病原菌,可污染多种水产品,并引起人的食物中毒,其致病性与溶血素密切相关,如直接耐热溶血素(TDH)、TDH-相关溶血素(TRH)、不耐热溶血素(TLH)。用PCR方法对分离自浙江省部分地区的副溶血弧菌临床和海产品分离株的3种溶血素基因进行检测。结果表明,所有副溶血弧菌菌株均可检测到tlh基因;11株临床分离株均检测到tdh基因,而42株水产品分离株中只有1株检出tdh基因,携带tdh的分离株神奈川试验(KP)均为阳性。所有分离菌株中均未检测到trh基因以及其尿素酶试验呈阴性,由此可知trh基因可能与尿素酶基因连锁。副溶血弧菌分离株中致病性相关毒力因子TDH的阳性率极低,然而副溶血弧菌性食物中毒发生率较高,它们之间的关系及其发病机制还有待深入研究。     

辽宁省2014‒2016年副溶血性弧菌毒力基因及 血清型、耐药性

摘要：目的 研究辽宁省近三年副溶血性弧菌毒力基因携带、血清型分布及抗生素的耐药情况,为副溶血性弧菌疾病防治提供科学依据。方法 运用多重荧光定量PCR对2014?2016年共计317株食品中和临床分离出的副溶血性弧菌进行毒力基因tdh、trh和tlh检测,同时进行血清分型,并用肉汤稀释法测定对15种抗生素的耐药性。结果 317株分离菌中均携带tlh基因,其中有50.5％的菌株携带tdh基因。167株临床分离株中158株携带tdh基因,检出率为94.6％。317株副溶血性弧菌中85株不能进行K分型,其他菌株共分为29个血清型,167株临床分离株中71.3%为血清型为O3:K6。150株食品分离株中8%为血清型O2:K28,6%为血清型O2:K3。317株副溶血性弧菌对头孢唑啉耐药率达36.9%。结论 辽宁省副溶血性弧菌临床分离株多携带tdh毒力基因,食品分离株毒力基因tdh、trh携带率低。临床分离株中O3:K6血清型菌株均携带tdh基因,且更易产生耐药。辽宁省副溶血性弧菌食源性疾病菌株以携带tdh基因的O3:K6型菌株为主。食品分离株血清型分布比较分散,O2血清群为主要流行血清型。辽宁省地区副溶血性弧菌主要对β-内酰胺类和大环内酯类抗生素产生耐药性。     

辽宁省食源性副溶血性弧菌毒力基因、血清分型及耐药性分析

目的 研究辽宁省2017-2020年市售水产品及其制品中分离的158株副溶血性弧菌的毒力基因、血清分型和耐药性,为食源性疾病的暴发和散发进行评估和预警.方法 采用多重荧光定量PCR技术对毒力基因tlh、tdh和trh进行检测,同时检测血清分型;采用肉汤稀释法测定副溶血性弧菌MIC值并分析其耐药性.结果 158株副溶血性...     

副溶血性弧菌耐热性直接溶血素(TDH)的研究进展

副溶血性弧菌(Vibrio parahaemolyticus)是海产品中一种常见的食源性致病菌,常导致水产养殖动物患病或者引起食物中毒。耐热性直接溶血素(thermotolerant direct hemolysin,TDH)是副溶血性弧菌最为重要的致病因子之一。本文围绕tdh基因在弧菌属中的广泛分布与传播、tdh基因的多样性及其表达调控、TDH的蛋白结构及其生物活性进行了综述,并对未来TDH的研究方向进行了展望。旨在进一步了解由副溶血性弧菌感染所引起的病症,为预防副溶血性弧菌的感染和临床治疗提供理论支撑。     

副溶血弧菌的毒力基因表达调控的分子机制

副溶血弧菌是革兰氏阴性嗜盐细菌,是海洋脊椎动物和无脊椎动物中主要致病菌,也是引起人类急性肠胃炎、败血症和坏死性筋膜炎等疾病的主要病原体。在过去,由副溶血弧菌引起的致病感染在世界范围内有不断增加的趋势。副溶血弧菌的致病性与其自身产生的多种毒力因子有关,这些毒力因子包括粘附因子、脂多糖、溶血素、III型分泌系统、VI型分泌系统、铁摄取系统、蛋白酶、外膜蛋白等。然而,这些毒力因子的表达都受到环境因子以及宿主体内信号因子的调控。副溶血弧菌通过感知外界生存环境的各种信号因子,从而激活体内不同的信号通路,进而诱导不同的毒力因子的表达。本文主要对副溶血弧菌毒力因子表达调控的分子机制进行综述,为更好地理解宿主与病原体的相互作用对副溶血弧菌的致病机制的影响,以及为今后预防和治疗由副溶血弧菌所引起的疾病提供理论参考。     

副溶血弧菌的致病机制

副溶血性弧菌是引发微生物食源性疾病的首要病原菌,其在临床上主要引起3种疾病,即胃肠炎、伤口感染和败血症。经过多年的研究,人们对副溶血性弧菌的致病机制有了一定的认识。我们着重介绍副溶血性弧菌的主要毒力因子、毒力基因表达调控及常用的毒力表型研究方法。     

2013‒2015年杭州地区急性腹泻患者来源 副溶血弧菌毒力基因及耐药性调查

摘要：目的 对2013?2015年杭州地区腹泻患者副溶血弧菌（Vibrio parahaemolyticus）毒力基因的携带和耐药进行调查研究。方法 可疑菌株用全自动细菌鉴定仪（VITEK2 Compact,生物梅里埃,法国）进行鉴定,用PCR方法检测其8种毒力基因,用纸片扩散法检测13种抗生素的敏感性。结果 120株副溶血弧菌中,tdh+或trh+的致病菌株占95.0%（114株）,tdh-且trh-的非致病株占5.0%（6株）。所有120株副溶血弧菌均含有T3SS1基因,T3SS2α基因主要存在于tdh+/trh-的菌株中,T3SS2β存在于trh+的菌株中,2株tdh-的菌株首次检出T3SS2α基因。本研究中大流行菌株占64.2%（77株）,非大流行菌株占35.8%（43株）。多达65.8%的副溶血弧菌对氨苄西林耐药,而90.0%以上的副溶血弧菌对其他抗生素包括喹诺酮类、第三代头孢菌素类、氨基糖苷类、四环素类和磺胺类抗菌药物较敏感。结论 杭州地区腹泻来源的副溶血弧菌多为大流行菌株,对常见抗菌药物敏感性高,但耐药率有所上升,要加强监测并引起临床重视。     

荧光定量PCR法检测副溶血弧菌tlh和tdh基因的表达差异

副溶血弧菌是广泛存在于近海区域,盐湖和海产品中的食源性致病菌,会引起大规模的食物中毒。TLH(不耐热溶血毒素)和TDH(耐热直接溶血毒素)是副溶血弧菌最主要的毒力基因,通过比较毒力基因的表达量可以间接比较同种菌株在不同应激条件下以及不同菌株之间的毒力差异。本文以在不同条件下培养的3株Vp为材料,分别提取其总RNA,以16S rRNA为内标基因,运用荧光定量PCR技术检测副溶血弧菌TLH和TDH基因在不同应激条件下的表达差异。结果表明:不同菌株和同种菌株在不同应激条件下tlh、tdh基因表达差异均显著;tlh的最适表达条件分别为5%盐度和20°C;tdh的最适表达条件分别为1%盐度和25°C。运用SPSS软件对实验结果进行统计学分析表明:菌株对tlh表达的影响大于盐度大于温度;菌株对tdh表达的影响大于温度大于盐度。     

近岸及河口环境中副溶血弧菌的生态适应性及其主要毒力基因分布特征

副溶血弧菌作为一种革兰氏阴性海洋菌,在海洋及河口环境中普遍存在,并占据了多种生态位。近年来,近岸及河口环境中副溶血弧菌引发疾病事件已成为国内外研究热点。该文综述了沿海地区副溶血弧菌的分布规律,着重阐述了影响副溶血弧菌在近岸沿海分布的主要环境生态因子,以及副溶血弧菌的主要毒力基因tdh、trh和tlh的分布特征,为开展近岸及河口环境中副溶血弧菌分布研究及沿海生态系统中副溶血弧菌相关疾病的暴发预测打下基础。     

霍乱弧菌和副溶血弧菌分离株的gyrB基因系统发育分析

依据gyrB基因部分编码序列构建系统发育树以分类和鉴别霍乱弧菌和副溶血弧菌,并探讨其种系发生关系。扩增并测序13株霍乱弧菌、8株副溶血弧菌、2株嗜水气单胞菌及1株类志贺邻单胞菌的gyrB基因(编码DNA促旋酶B亚单位)序列,并采用距离法与最大似然法构建系统发育树。两种方法所构建的树结构完全一致,霍乱弧菌、副溶血弧菌、嗜水气单胞菌及类志贺邻单胞菌各自形成一个独立的簇。其中,霍乱肠毒素基因(ctxA)阳性的霍乱弧菌(8株O139群与2株O1群ElTor型)聚类成一分枝;3株副溶血弧菌临床株(1株2002年流行株,2株2004年分离株)与1日本菌株及2001年1株自环境分离的毒力株聚类。系统发育分析靶分子gyrB基因可以良好区分上述4种常见病原菌。产毒O139群霍乱弧菌与产毒O1群ElTor型霍乱弧菌关系密切。副溶血弧菌环境毒力株与本地区临床主要流行株在系统发育关系上较为接近,可能是潜在的致病菌。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.