Virus diseases of farmed shrimp in the Western Hemisphere (the Americas): a review

Penaeid shrimp aquaculture is an important industry in the Americas, and the industry is based almost entirely on the culture of the Pacific White Shrimp, Litopenaeus vannamei. Western Hemisphere shrimp farmers in 14 countries in 2004 produced more than 200,000 metric tons of shrimp, generated more than $2 billion in revenue, and employed more than 500,000 people. Disease has had a major impact on shrimp aquaculture in the Americas since it became a significant commercial entity in the 1970s. Diseases due to viruses, rickettsial-like bacteria, true bacteria, protozoa, and fungi have emerged as major diseases of farmed shrimp in the region. Many of the bacterial, fungal and protozoan caused diseases are managed using improved culture practices, routine sanitation, and the use of chemotherapeutics. However, the virus diseases have been far more problematic to manage and they have been responsible for the most costly epizootics. Examples include the Taura syndrome pandemic that began in 1991-1992 when the disease emerged in Ecuador, and the subsequent White Spot Disease pandemic that followed its introduction to Central America from Asia in 1999. Because of their socioeconomic significance to shrimp farming, seven of the nine crustacean diseases listed by the World Animal Organization (OIE) are virus diseases of shrimp. Of the seven virus diseases of penaeid shrimp, five are native to the Americas or have become enzootic following their introduction. The shrimp virus diseases in the Americas are increasingly being managed by exclusion using a combination of biosecurity and the practice of culturing domesticated specific pathogen-free (SPF) stocks or specific pathogen-resistant (SPR) stocks. Despite the significant challenges posed by disease, the shrimp farming industry of the Americas has responded to the challenges posed by disease and it has developed methods to manage its diseases and mature into a sustainable industry.     

养殖对虾病毒致病性的初步研究

用从日本对虾分离的杆伏病毒扣长毛对虾分离的球伏病毒分别感染健康无病毒的日本对虾,对虾死亡率分别为６５％（杆状病毒组）和５０％（球状病毒组）,而对照组的死亡率仅为２５％,在诸环境因素中,温度的上升和低压可能是对虾病毒病发作的最重要诱因之一。     

A parvo-like virus disease of penaeid shrimp

Cultured populations of four penaeid shrimp species (Crustacea, Decapoda) from four separate culture facilities in Asia were found to be adversely affected by a disease of presumed viral etiology. Individual shrimp with the disease displayed nonspecific signs, including poor growth rate, anorexia, reduced preening activity, increased surface fouling, and occasional opacity of tail musculature. These signs were accompanied by mortalities during the juvenile stages, after apparently normal development through the larval and postlarval stages. Accumulative mortality rates in epizootics in Penaeus merguiensis and P. semisulcatus reached as high as 50 to 100%, respectively, of the affected populations within 4 to 8 weeks of disease onset. The principal lesion, common to all four species, was necrosis and atrophy of the hepatopancreas, accompanied by the presence of large prominent basophilic, PAS-negative, Fuelgen-positive intranuclear inclusion bodies in affected hepatopancreatic tubule epithelial cells (hepatopancreatocytes). These inclusion bodies presumably developed from small, eosinophilic, intranuclear bodies that were also present in the affected tissues. Electron microscopy of affected hepatopancreatocytes revealed aggregations of 22- to 24-nm-diameter virus particles within the electron-dense granular inclusion body ground substance. The virus particle size and morphology, the close association of the nucleolus with the developing inclusion body, and the presence of intranuclear bodies within developing inclusion bodies are similar to cytopathological features reported for parvovirus infections in insects and vertebrates. It is suggested that this presumed virus disease of cultured penaeid shrimp be called HPV for Hepatopancreatic Parvo-like Virus disease.     

对虾病毒病研究现状

对虾病毒病已严重危害世界对虾养殖业的发展,引起国内外学者的广泛关注。对近几年来对虾病毒病的研究现状和动态进行了概述,重点介绍了杆状病毒科(Baculoviridae)、细小病毒科(Parvoviridae)、呼肠孤病毒科(Reoviridae)、虹彩病毒科(Iridoviridae)、小RNA病毒科(Picornaviridae)、弹状病毒科(Rhabdoviridae)、被膜病毒科(Togaviridae)等几个科15种对虾病毒的特征、临床症状、病理特征、宿主范围和主要检测方法;对病毒病的传播途径、防治措施和存在的问题也进行了简要介绍。     

Analysis of expressed sequence tags (ESTs) from cocoa (Theobroma cacao L) upon infection with Phytophthora megakarya

Phytophthora megakarya, the causative agent of cacao black pod disease in West African countries causes an extensive loss of yield. In this study we have analyzed 4 libraries of ESTs derived from Phytophthora megakarya infected cocoa leaf and pod tissues. Totally 6379 redundant sequences were retrieved from ESTtik database and EST processing was performed using seqclean tool. Clustering and assembling using CAP3 generated 3333 non-redundant (907 contigs and 2426 singletons) sequences. The primary sequence analysis of 3333 non-redundant sequences showed that the GC percentage was 42.7 and the sequence length ranged from 101 - 2576 nucleotides. Further, functional analysis (Blast, Interproscan, Gene ontology and KEGG search) were executed and 1230 orthologous genes were annotated. Totally 272 enzymes corresponding to 114 metabolic pathways were identified. Functional annotation revealed that most of the sequences are related to molecular function, stress response and biological processes. The annotated enzymes are aldehyde dehydrogenase (E.C: 1.2.1.3), catalase (E.C: 1.11.1.6), acetyl-CoA C-acetyltransferase (E.C: 2.3.1.9), threonine ammonia-lyase (E.C: 4.3.1.19), acetolactate synthase (E.C: 2.2.1.6), O-methyltransferase (E.C: 2.1.1.68) which play an important role in amino acid biosynthesis and phenyl propanoid biosynthesis. All this information was stored in MySQL database management system to be used in future for reconstruction of biotic stress response pathway in cocoa.     

PCR检测中国对虾暴发性流行病毒靶基因的克隆和序列分析

An explosive epidemic disease of shrimp had occurred in China and the south Pacific coast. The causative agent is a new baculovirus called hypodermal and hematopoietic necrosis baculovirus (HHNBV) in China, and the pathogen is very much similar to Japanese panaeid rod-shaped DNA virus (PRDV) which caused mass mortality of shrimp. In order to distinguish both HHNBV and PRDV at molecular level, we have sequenced the PCR-targeted DNA fragment of HHNBV. One pair of PCR primers were prepared based on the PRDV DNA. The sequence of the PCR-targeted DNA of HHNBV is 975bp in length, and shares 99.7% homology with the PRDV. The sequence of PCR-targeted DNA of HHNBV-XIA differs from PRDV DNA in deleting three nucleotides (CAT) at 510～512 site. These characteristics of the sequence classified HHNBV and PRDV as strains of different genotypes.     

浅论围湖造田的利弊——兼谈枞阳县湖区围垦后资源的利用问题

一枞阳县位于安徽中南部,紧靠长江北岸,东经117°04′—117°44′,北纬30°39′—31°05′之间,无霜期251天,年降雨量1323.6毫米,总面积1,808.1平方公里,水田462,664亩,旱地197,135亩,境内有白荡、陈瑶、菜子三个重点湖泊。解放初期湖泊水面为51.9万亩,占总水面84.8%。1958年开始围湖造田,水面大大减少,自然生态也发生相应变化(见表1)。这些变化在人多、田少、征购任务重的情况下,为解决粮食供需矛盾起了一定作用。据统计,六十年代中期圩田生产粮食9,000多万斤,人均增粮140斤,七十     

对虾-罗非鱼-缢蛏封闭式综合养殖的水质研究

研究了对虾、罗非鱼和缢蛏封闭式综合养殖的环境状况.结果表明,混养各组环境状况总体要优于单养组.实验期间混养组DO的波动幅度略小于单养组,最低值则高于单养组;各混养组COD值和水层细菌数量相互差异不显著,但各混养组均显著低于单养组(t检验,α<0.05),混养围隔水体有机质含量明显低于单养;混养各围隔组中浮游生物生物量、Chl.a均低于单养组,滤食性动物对浮游生物的压制作用明显.在底泥中,混养组N、P的积累量比单养组低39.76%和51.26%,混养组细菌总数则比单养组低7.63%.本研究表明,封闭式综合养殖可以大大减少注入近海的养殖污水的排放量,从而降低对近海水质的污染.     

Development of simple sequence repeat markers from expressed sequence tags of the black tiger shrimp (Penaeus monodon)

In this study, we describe the development of expressed sequence tag-simple sequence repeat markers from expressed sequence tags of the black tiger shrimp (Penaeus monodon) deposited in public sequence databases. A total of 46 primer pairs were designed and screened on 26 individuals of P. monodon from a natural population. Of these, 16 primer pairs showed polymorphic profiles with between two and five alleles per locus. The average unbiased and direct count heterozygosities were 0.4662 and 0.3516, respectively. Cross-amplification was tested with five individuals of Penaeus vannamei and polymorphic products were detected at five loci.     

Isolation and characterization of 14 polymorphic microsatellite markers for the blue and red shrimp, Aristeus antennatus (Crustacea, Decapoda)

Eighteen microsatellite loci were isolated and characterized from the blue and red shrimp, Aristeus antennatus Risso 1816, a commercially exploited marine crustacean widely distributed throughout the Mediterranean Sea and in the eastern Atlantic. Polymorphism was assessed in a population (n = 20) from the southwestern Sardinian seas; 14 loci resulted polymorphic and showed from three to 13 alleles. The observed heterozygosity ranged from 0.2 to 0.85. These microsatellites will be potentially useful for the study of A. antennatus population genetic structure.     

Mass spectrometry-based prokaryote gene annotation

MS combined with database searching has become the preferred method for identifying proteins present in cell or tissue samples. The technique enables us to execute large-scale proteome analyses of species whose genomes have already been sequenced. Searching mass spectrometric data against protein databases composed of annotated genes has been widely conducted. However, there are some issues with this technique; wrong annotations in protein databases cause deterioration in the accuracy of protein identification, and only proteins that have already been annotated can be identified. We propose a new framework that can detect correct ORFs by integrating an MS/MS proteomic data mapping and a knowledge-based system regarding the translation initiation sites. This technique can provide correction of predicted coding sequences, together with the possibility of identifying novel genes. We have developed a computational system; it should first conduct the probabilistic peptide-matching against all possible translational frames using MS/MS data, then search for discriminative DNA patterns around the detected peptides, and lastly integrate the facts using empirical knowledge stored in knowledge bases to obtain correct ORFs. We used photosynthetic bacteria Synechocystis sp. PCC6803 as a sample prokaryote, resulting in the finding of 14 N-terminus annotation errors and several new candidate genes.     

白斑综合症病毒与对虾血淋巴细胞的体外结合实验

通过差速离心和蔗糖密度梯度离心,从感染了白斑综合症病毒(WSSV)的病虾头胸部分离了WSSV,利用地高辛对病毒蛋白进行了标记(DIG-WSSV),以体外培养的对虾血淋巴细胞为吸附基底,观察和分析了病毒与细胞间的结合现象及特性。以NBT/BCIP为酶反应显色底物观察到在细胞周围形成许多暗紫色颗粒,证实病毒与细胞间存在着稳定的结合。以OPD为酶反应显色底物分析了结合反应的特性:当DIG-WSSV维持恒定值时,随着血淋巴细胞数量的增加结合显色增强,细胞数量达到1.2104cells/孔,492nm处的吸光值达到饱和;当血淋巴细胞数量维持恒定值时,随着DIG-WSSV蛋白含量的增加显色增强,且在DIG-WSSV的蛋白浓度达到4g/孔时,492nm处的吸光值达到饱和;未标记WSSV可竞争抑制血淋巴细胞与DIG-WSSV间的结合作用。进一步的研究得出:4℃下,随着结合时间的延长显色增强,但继续延长结合时间显色反而减弱;缓冲液的渗透压对结合结果影响甚微,而酸性条件利于病毒与细胞间的结合。37℃孵育对病毒结合活性影响不大,55℃和70℃孵育可显著影响病毒的结合活性;短时间超声波处理病毒可增加病毒结合能力,长时间超声波处理可破坏病毒结合能力;有机溶剂处理同样可破坏病毒结合能力,其中尤以氯仿/甲醇的处理更为激烈;不同的去垢剂对病毒结合活性的影响结果不同:SDS和脱氧胆酸钠可以降低病毒的结合活性,而Triton X-100和NP-40可以提高病毒的结合活性。     

对虾—罗非鱼—缢蛏封闭式综合养殖的水质研究

研究了对虾,罗非鱼和缢蛏封闭式综合养殖的环境状况,结果表明,混养各组环境状态总体要优于单养组,实验期间混养组DO的波动幅度略小于单养组,最低值则高于单养组;各混养组COD值和水层细菌数量相互差异不显著,但各混养组均显著低于单养组（t-检验,α＜0．05）,混养围隔水体有机质含量明显低于单养;混养各围隔组中浮游生物生物量,Chl.a均低于且,滤食性动物对浮游生物的压制作用明显,在底泥中,混养组N,P的积累量比单养组低39．76％和51．26％,混养组细胞总数则比单养组低7．63％,本研究表明,封闭式综合养殖可以大大减少注入近海的养殖污水的排放量,从而降低对近海水质的污染。     

双抗体夹心ELISA法检测养殖对虾病毒的研究

用纯化的长毛对虾球状病毒（PPSV）和日本对虾中肠腺坏死杆状病毒（BMNV）制备新西兰兔抗BMNV和抗PPSV抗血清及Balb／c小鼠抗BMNV和抗PPSV抗血清,建立检测PSV和BMNV的双抗体夹心ELISA检测法,结果表明,双抗体夹心ELISA法具有较高的灵敏度,可以从100μl待测组织匀浆液中检测到50ng的PPSV蛋白,以及100ng的BMNV蛋白。不同病毒抗血清无交叉反应性,用该ELISA技术检测养殖对虾和多种采自养殖虾池及其附近的近海岸生物,发现相当比例的外观正常的对虾和近海岸生物已呈阳性反应     

PCR法检测对虾皮下和造血器官坏死杆状病毒

皮下和造血器官坏死杆状病毒（ＨＨＮＢＶ）［１］、对虾杆状ＤＮＡ病毒（ＰＲＤＶ）［２］和白斑杆状病毒（ＷＳＢＶ）［３］是近年来引起全球对虾暴发性死亡的病原。这三种病毒同属杆状病毒属Ｃ杆状病毒亚群中的新病毒,在流行病学和病理学特征上十分类似,因此,我们...     

Variations circadiennes des activités estérases de l'hémolymphe de Penaeus japonicus

The esterase activities of Penaeus japonicus hemolymph, revealed by a mixture of α- and β-naphtylacetate exhibit tricircadian variations under an LD:12-12 photoperiod. During the 24 h period, the total esterase activities can vary by 0,12 to 0,64 V/μg of protein. Under the experimental conditions adopted, circadian variations of the hemolymph esterase activities are observed whatever the sex and molt stage; the sex factor seems to be predominant for the esterase activities studied. Concurrently, a circadian rhythm of individual variabilities is observed for both sexes. The variabilities are assessed from the ratio of standard deviations on the esterase activity means, for each hour of experimentation. The minimum variabilities correspond to maximum total or specific esterase activities for the females whereas they precede the maximum esterase activities for males.