应用间接荧光抗体技术快速检测花鲈病原菌——鳗弧菌

以花鲈（Lateolabrax japonicus)弧菌病的病原菌-鳗弧菌（Vibrio anguillarum)W-1为抗原，制备兔抗血清；利用异硫氰酸荧光素标记的羊抗兔免疫球蛋白（FITC-IgG）为荧光标记二抗，并以罗丹明标记的牛血清白蛋白为背景染色，建立检测鳗弧菌的间接荧光抗体快速检测技术。应用该技术对人工感染后的花鲈组织（肌肉、鳃、肠、肾）样品和养殖水体样品进行了鳗弧菌检测，结果显示间接荧光抗体技术不仅可以用于诊断发病的感染花鲈，也可用于检测带菌状态或未发病的感染花鲈。     

海水网箱养殖高体Shi弧菌病致病菌研究

从患病高体Ｓｈｉ病灶上分离到７株可疑致病菌，人工感染试验证明，菌株９５－５－３和９５－５－５为强毒菌株，这２株菌进行人工感染，死亡率均为１００％，症状与自然发病相似。这２株菌的特征一致，根据形态有主生理生化特征，应归入哈维氏弧菌。药敏实验的结果表明，磺胺类药物和先锋必素对致病菌有较强的抑制作用。     

海水网箱养殖高体鱼师弧菌病致病菌研究

从患病高体鱼师病灶上分离到７株可疑致病菌，人工感染试验证明，菌株９５－５－３和９５－５－５为强毒菌株，这２株菌进行人工感染，死亡率均为１００％，症状与自然发病相似。这２株菌的特征一致，根据形态有主生理生化特征，应归入哈维氏弧菌。药敏实验的结果表明，磺胺类药物和先锋必素对致病菌有较强的抑制作用。     

养殖牙鲆弧菌病病因菌初步研究

１９９８年７月自荣成市寻山水产集团总公司养鱼场养殖牙鲆病死鲆体内分离到１株细菌，经人工感染试验证明是鲆菌病病原菌，该菌主要特征为：革兰氏阴性，弧状，以极生单鞭毛运动，氧化酶阳性，发酵葡萄产酸不产气，不产生Ｈ２Ｓ，不产生色素，生长温度范围１０－４２℃，pH范围６－１０，盐度范围０.5-6,经Ｂiolog Microstation System鉴定为河川弧菌－Ｉ，该菌株对环丙沙星，氟哌酸，利福平，呋喃唑酮，呋喃妥因，红霉素，链老素等药物敏感.     

紫贻贝(Mytilus edulis Linnaeus)大量死亡原因的初步研究

从发病紫贻贝（Mytilus edulis）的内脏团内分离出一株菌SS1，通过人工感染试验，证实其为致病菌。经形态、生理生化等几项指标鉴定，该菌株性状与溶藻弧菌基本相符。药物敏感试验结果表明羧苄青霉、万古霉素、克林霉索、氨苄青霉索、阿莫西林等9种药物对该菌株均有明显的抑制作用。     

紫贻贝(Mytilus edulis Linnaeu)大量死亡原因的初步研究

从发病紫贻贝（Mytilus deulis）的内脏团内分离出一株菌SS1，通过人工感染试验，证实其为致病菌。经形态、生理生化等几项指标鉴定，该菌株性状与溶藻弧菌基本相符。药物敏感试验结果表明羧苄青霉、万古霉素、克林霉素、氨苄青霉素、阿莫西林等9种药物对该菌株均有明显的抑制作用。     

斜带石斑鱼病原菌(哈维氏弧菌)的分离与鉴定

从患病斜带石斑鱼 (Epinepheluscoioides)肝脏组织分离到EcGY0 2 0 4 0 1菌株 ,经人工感染、回归感染实验证实为致病菌。通过API系统和菌体常规形态特征、培养特性和生理生化反应指标测定以及 16SrRNA测序分析等综合鉴定 ,Ec GY0 2 0 4 0 1菌株为弧菌属哈维氏弧菌 (Vibrioharveyi) ,其半致死剂量LD50 为 2 .7× 10 6CFU/g鱼体重。药敏试验结果表明 ,EcGY0 2 0 4 0 1菌株对利福平、四环素、喹诺酮类及头孢曲松等抗生素较为敏感     

江苏南部河蟹幼苗培育系统中致病性弧菌的分离诊断

从急性死亡的河蟹大眼幼体体内分离得到3q8T－2、3q7T－4等菌株,经细菌学鉴定为副溶血性弧菌,回归试验表明这几种弧菌均能感染健康动物致死亡。通过药敢试验,发现试转药1号、悉复欢等对其有较强抑制作用。     

大连地区裙带菜绿烂病病原的研究↑（*）

使用涂布平板法测定发病期裙带菜栽培水域中的异养细菌数量、病藻带菌量。显微镜压片观察患病藻体细胞中有细菌寄生，从病藻上分离到优势菌株４株，人工感染试验证明为绿烂病的病原菌，经系统分类鉴定定名为火神弧菌，新霉素、庆大霉素等对该菌具有明显的抑制作用。     

鲍弧菌病的防治研究

在实验室进行鲍人工感染弧菌病的防治试验。结果说明:使用鲍防病配合饲料对于防治养殖鲍弧菌病效果显著。并从东山养鲍场患病的九孔鲍体上分离到一种致病菌,经鉴定为溶藻弧菌(Vibrio alginolyticus)。     

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.