中国对虾呼肠孤样病毒感染的电镜观察

呼肠孤病毒在自然界广泛存在于脊椎动物、无脊椎动物和植物中.水产动物呼肠孤病毒感染曾见于鱼、贝、蟹.近几年随着对对虾病毒病害研究的日益重视,在对虾中也发现呼肠孤病毒的感染.Tsing等[1]最早于1987年在法国南部养殖的日本对虾(P.japonicus)幼虾中发现呼肠孤病毒感染.Krol等[2]于1990年在试验感染的南美白对虾(P.vannamei)中发现呼肠孤样病毒与对虾杆状病毒混合感染.中国大陆养殖的中国对虾自1993年全面暴发流行病以来,许多学者进行了对虾流行病的病原学、流行病学及诊断和防治方法的研究,部分学者曾在中国对虾(P.chinensis)中观察到呼肠孤样病毒颗粒[3],但未报道较详细的电子显微镜观察资料.     

养殖对虾病害生态防治的探讨

养殖对虾病害的生态防治尚处于探索研究阶段。从养殖水环境控制、养殖方式和结构调整等方面,综合分析了近年虾病生态防治研究工作的成果,提出要建立一套科研、生产、推广的完整生态防治体系应从以下几方面着手：调查虾池及近海水域生态环境,加强近海环境保护;利用复合生态渔业提高虾池能量转换效率,达到生态效益和经济效益的统一;用模拟试验研究,为评价和完善对虾养殖管理对策提供根据。     

不同模式对虾养殖的自身污染及其环境效应

对虾养殖污染主要来源于过量的饵料,对虾排泄物、粪便和生物遗骸溶出或分解产生的N、P营养盐和有机质,以及在养殖过程中所投放的化学或抗生素类药物残留。本文根据有关调查和研究的资料,阐述对虾养殖自身污染的机制,着重分析目前我国南方较为普遍的高位池和低位池对虾养殖模式的特点与自身污染的关系及其环境效应,并提出针对这两种养殖模式的污染防治对策。     

渤海西岸急性致死性对虾病的病毒病原研究

目前,在全世界养殖及野生对虾中已发现至少有10～20种病毒。近年来,我国沿海省份相继发生养殖对虾大批死亡现象,造成大部分虾场严重减产甚至绝收,对滩涂对虾养殖业造成巨大经济损失。虾病已成为对虾养殖业的重要限制因素。因此研究虾病的病原,传染途径,对有效防治暴发流行性虾病,发展对虾养殖业具有重要意义。本文报导我们对渤海西岸养殖的中国对虾暴发流行病病原的部分研究结果。1材料与方法1．五病好和病虾组织的超薄切片观察病虾取自辽宁锦西首钢前所虾场加工厂冰冻中国对虾,以及上海东海水产研究所固定保存的活病虾组织。从已死…     

一株凡纳滨对虾源维氏气单胞菌的分离鉴定及药敏特性

【目的】凡纳滨对虾(Litopenaeus vannamei)是世界范围内最主要的对虾养殖品种之一,2017年5-6月上海某凡纳滨对虾养殖场出现不明原因的死亡病例,发病急,死亡率高。从患病凡纳滨对虾体内分离到一株优势菌AVZ01,旨在确定病因并筛选出敏感药物,为今后凡纳滨对虾维氏气单胞菌(Aeromonas veronii)的防治提供参考。【方法】从患病凡纳滨对虾肝胰腺和肠道中分离致病菌,通过理化特性及16S r RNA基因序列分析进行鉴定,通过人工感染试验确定病原,使用Bliss法计算出半数致死剂量(LD50),并通过纸片扩散法进行药敏试验。【结果】从患病凡纳滨对虾体内分离到一株优势菌AVZ01,进行人工回归感染试验后,对虾发病症状与自然发病症状相似,凡纳滨对虾的LD50为8.7×105 CFU/m L。根据该菌株的形态特征、理化特性、16S r RNA基因序列分析,综合判断该病原菌为维氏气单胞菌。药敏试验结果显示,该菌株对米诺环素、诺氟沙星、庆大霉素等16种抗生素高度敏感,对青霉素、苯唑西林、头孢氨苄等9种抗生素耐药。【结论】分离菌株AVZ01对凡纳滨对虾有较强的致病性,养殖过程中可选用庆大霉素及新霉素等药物进行防控。     

凡纳对虾淡化养殖池浮游纤毛虫研究

在对虾养殖环境,纤毛虫能摄食大量的腐质和藻类,促进对虾养殖水体的自身净化;但缘毛类 Peritrichida 和吸管虫类Suctorida纤毛虫能大量固着生活在对虾的附肢、鳃等部位,是对虾养殖的重要危害生物。在我国,对海水、盐碱池和淡水养殖环境的浮游动物(包括纤毛虫)有较多的研究,对河口区斑节对虾淡化养殖环境浮游生物也有报道,本文报道了珠海市斗门区某凡纳对虾 Litopenaeus vannamei(南美白对虾)养殖基地44口淡化养殖虾池浮游纤毛虫种类及数量组成, 并对其中 1-5号虾池养殖过程中的纤毛虫种群的动态变化进行了研究,以期为凡纳对虾淡化养殖提供参考。       

生态养殖

<正>加强海水养殖管理,合理确定养殖规模,调整优化海水养殖布局,积极拓展深水大网箱等离岸养殖,支持工厂化循环水养殖,加快水产养殖标准化建设和健康养殖标准推广应用。摘编自《国家海洋事业发展"十二五"规划》我国是对虾养殖大国,对虾产品总量位居世界前列,2012年我国的对虾贸易额占全球水产品贸易额的15%,总产量占全球总量的40%以上。湛江拥有全国最大的对虾种苗繁育、养殖、饲料生产和加工出口基地。隶属于湛江的雷州乌石镇,因拥有湛江为数不多的国家中心渔港,也是湛江对虾养殖重点区域之一。该镇的居民世代以海洋     

对虾小个体亲虾的人工繁殖试验

浙江省自1972年开始群众性试养对虾以来,养殖的品种主要是黄渤海产的中国对虾(Penaeus orientalis),它具有个体大、生长快、适盐性广等优点。然而浙江沿海未发现有中国对虾的亲虾及虾苗资源。要解决养殖的苗种,必须从山东运苗,花很大的人力、物力,不利养虾事业的发展。为了就地解决养殖对虾所需苗种,     

对虾白斑综合征病毒中国地方株变异区基因的比较

对虾白斑综合征病毒(White spot syndromevirus,WSSV)是对虾养殖的主要病原之一,它是目前发现的基因组最大的动物病毒,为环状双链DNA病毒[1,2],全基因组序列分析结果显示,对虾白斑综合征病毒和其他杆状病毒相差甚远,最新病毒分类报告已将该病毒划归新建立的线头病毒科(Nima-viridae)白斑病毒属(Whispovirus)[3,4]。目前Gen-Bank公布有3个版本的WSSV全序列[1,2],其基因组大小的测定结果相差较大。不同的WSSV毒株可能在形态结构、理化性质上无法区分,但病毒基因组限制酶切片段长度多态性(RFLP)可以将之区分开来,Marks等[6,7]通过计…     

对虾白斑综合症病毒与虾鳃细胞膜特异性结合关系的确立

对虾白斑综合症病毒(White spot syndrome virus,WSSV)是养殖对虾的一个主要病原,也是目前发现的基因组最大的动物病毒(基因组约290kDa,双链环状)。WSSV病毒粒子为卵形杆状,外被囊膜,囊膜在尾部延伸成一长尾。它不仅能感染对虾,还能感染其它淡水及海水甲壳类。养殖对虾被感染后,3—10d内累积死亡率可达100％,给对虾养     

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.