河鲀毒素的色谱检测法

河■毒素是一种重要的天然海生毒素。１９０９年日本学者田原纯首先从河■鱼中发现，并定名Ｔｅｔｒｏｄｏｔｏｘｉｎ。１９５０年～１９５７年间，横尾晃、津田藤介等人首先从红鳍东方■，紫色东方■卵巢中独立地分离到了结晶态的河■毒素。其为无臭、易潮解的白色结晶体，分子式Ｃ１１Ｈ１７Ｎ３Ｏ８，相对分子量为３１９．２７。该毒素结构的测定由Ｗｏｏｄｗａｒｄ（哈佛大学）、平田和后藤（名古屋大学）及津田小组（东京大学—三共中央研究所）等分别完成。其结构如下图所示： 河■毒素在发现之初人们就在不断寻找其更好的检测方法。…     

长江口花鲈的生长和食性

花鲈为沿海及河口的经济鱼类，亦可溯河生活于淡水。在长江口水域，花鲈属中型鱼类，其体长和体重的相关关系式为：Ｗ＝０．０６０５Ｌ＾２．６３４６（ｒ＝０．９８７８），生长方程为：Ｌｔ＝１００．９９５７［１－ｅ＾０．１７６８（ｔ＋０．７６３３）］，Ｗｔ＝１１５４２．２６［１－ｅ＾－１７６８（ｔ＋０．７６３３）］＾２．６３４６，体重生长拐点ｔｒ＝４．７龄，拐点处体重为３２８１．４克。早期幼鱼以浮游动物为食，     

制度建设

《中国渔船船东互保协会互保凭证管理办法》（渔保保发［2000］9号）于2000年2月23日颁布实施。《中国渔船船东互保协会审批权限规定》（渔保保发［2000］10号）于2000年2月28日颁布实施。《中国渔船船东互保协会财务管理暂行办法》（渔保财发［2000］11号）于2000年3月1日颁布实施。制度建设     

我国海产贝类体中的麻痹性毒素及其来源

在目前已知的海洋藻类毒素中麻痹性毒素（Ｐａｒａｌｙｔｉｃ　Ｓｈｅｌｌｆｉｓｈ Ｐｏｉｓｏｎ,ＰＳＰ）是毒害事件发上频率最高、对人类影响最为严重的一类毒素。文献记载最早发生该类中毒事件的地区,主要是在欧洲和北美的一些海域［１、２］。据不完全统计,在我国因食用染毒贝类引起的中毒事件有几十起,主要发生在东海和南海海域。因此,贝类麻痹性毒素的含量状况和上市贝类的质量是消费者极为关注的问题,同时也是有关海域渔业可持续发展的保证条件之一。为维护和发展贝类养殖业,保证海产品的质量和促进海产品的出口贸易等,深入…     

咪唑类离子液体处理对草鱼CYP3A和PXR基因表达的影响

细胞色素Ｐ４５０是一类含有亚铁血红素的超家族单加氧酶,参与许多外源物质（包括药物、环境化合物等）和内源性物质（如激素）的代谢转化。ＣＹＰ３Ａ是Ｉ相解毒酶系Ｐ４５０家族中的重要成员,在肝脏对外源毒物解毒和内源激素的代谢过程中发挥重要作用。为探讨草鱼（Ctenopharygodon idellus）肝脏ＣＹＰ３Ａ在溴化１-辛基３-甲基咪唑离子液体（［Ｃ８ｍｉｍ］Br）的解毒过程作用以及鱼体对［Ｃ８ｍｉｍ］Br的解毒是否通过ＰＸＲ-ＣＹＰ３Ａ转录调控途径作用,通过预试验获取［Ｃ８ｍｉｍ］Br对草鱼的急性毒性效应,选取２２ｍｇ／Ｌ（１／１０ＬＣ５０）和１０９ｍｇ／Ｌ（１／２ＬＣ５０）浓度组［Ｃ８ｍｉｍ］Br对草鱼染毒２４ｈ,荧光定量ＰＣＲ检测ＣＹＰ３Ａ和ＰＸＲ的表达情况。结果表明,草鱼肝脏ＣＹＰ３Ａ水平与对照组相比极显著上升（Ｐ＜００１）,ＰＸＲ基因表达量与对照组相比也极显著升高（Ｐ＜０．０１）,ＣＹＰ３Ａ与ＰＸＲ基因表达水平呈现出一定的相关性;推测在草鱼体内ＰＸＲ可能就是［Ｃ８ｍｉｍ］Ｂｒ作用于ＣＹＰ３Ａ的受体。     

柴河水库大银鱼生殖腺组织学的初步研究

对自然分布的大银鱼（Ｐｒｏｔｏｓａｌａｎｘｈｙａｌｏｃｒａｎｉｕｓ）成熟和产卵有过报道［１］,人工增养殖水域大银鱼的生物学和人工繁殖有过研究［２,３］,但其生殖腺组织学尚未见报道。大银鱼作为北方地区重要的移植增殖鱼类,我们在柴河水库移植增殖过程中,对...     

两种草鱼出血病病毒株的比较↑（*）

草鱼出血病病毒（ＧＣＨＶ）是我国分离成功的第１种鱼类病毒,隶属于呼肠孤病毒科水生呼肠孤病毒属（Ａｑｕａｒｅｏｖｉｒｕｓ）［７,１４］。ＧＣＨＶ是草鱼出血病的病原体,可导致当年龄草鱼（Ｃｔｅｎｏｐｈａｒｙｎｇｏｄｏｎｉｄｅｌｈｕｓ）鱼种大批死亡［５,８...     

鱼类基因分子生物学及转基因鱼研究进展↑（*）

真核基因分子克隆技术的建立，提供了从核苷酸水平了解鱼类基因结构的手段。鱼类基因的分子克隆始于八十年代初、中期对虹鳟（Ｓａｌｍｏｇａｉｒｄｎｅｒｉ）鱼精蛋白基因［５２］和美洲黄盖鲽（Ｐｓｅｎｄｏｐｌｅｕｒｏｎｅｃｔｅｓａｍｅｒｉｃａｎｕｓ）抗冻蛋白（ＡＦＰ）基因［２２］的分子克隆，随后扩展到其他极地鱼类ＡＦＰ基因，接着扩展到鱼类生长激素（ＧＨ）基因、催乳激素（ＰＲＬ）基因、生长催乳素（ｓｏｍａｔｏｌａｃｔｉｎＳＬ）基因等数十个基因。对这些控制鱼类重要生理机能的基因结构的认识，无论在理论上还是在渔业…     

池养尖吻鲈和花鲈的生长特性

尖吻鲈（Ｌａｔｅｓｃａｌｃａｒｉｆｅｒ）、花鲈（Ｌａｔｅｏｌａｂｒａｘｊａｐｏｎｉｃｕｓ）为河口性鱼类,可作为池塘养殖的对象。尖吻鲈的适宜生长水温为２５℃～３４℃,快速生长年龄在Ⅰ～Ⅱ龄;花鲈在珠江口地区一年四季均能生长,快速生长年龄在Ⅲ～Ⅳ龄。应用ＶｏｎＢｅｒｔａｌａｎｆｙ方程求得它们在人工饲养条件下体长、体重生长方程：尖吻鲈Ｌｔ＝７０６．５５５３［１－ｅ－０．５１２８（ｔ＋０．２０３２）］,Ｗｔ＝６５５４．４６４９［１－ｅ－０．５１２８（ｔ＋０．２０３２）］３．０３３５;花鲈Ｌｔ＝８８７．４９５８［１－ｅ－０．４０２５（ｔ＋０．０２０９）］,Ｗｔ＝１０８８２．１８８４［１－ｅ－０．４０２５（ｔ＋０．０２０９）］３．１４２７。它们的体重生长拐点分别位于１．９６和２．８２龄处。商品鱼的合理起捕时间应选在生长转折点。参照生物学指标,珠江口地区池养尖吻鲈、花鲈的上市商品鱼应为Ⅰ～Ⅱ龄和Ⅲ～Ⅳ龄,这不仅符合经济原则,也适应当地的消费习惯。     

不同投饵方式对黑鲪生长的影响

鱼类的生长受众多因素的影响,如温度、盐度、光周期、食物以及鱼类自身的生理状态等［１］。单就食物而言,生长就不仅受食物性质、食物数量的影响,而且还受投饵方式的影响［２,３］。在自然状态下,鱼类摄食有一定的周期性;在养殖中,投饵也常采用一定的时间间隔［４,５］,但研究不同投饵方式对鱼类生长的影响还较少。黑鲪（Ｓｅｂａｓｔｏｄｅｓｆｕｓｃｅｓｃｅｎｓ）是重要的海水养殖鱼种之一,目前关于黑鲪的研究还比较少［６］。本研究考察了不同投饵方式对黑鲪生长的影响,以期为其养殖提供基础数据。收稿日期：１９９８－１２…     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.