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1.
对蟹源拟态弧菌HX-4菌株外毒素的酶活性、溶血活性、细胞毒性和致死性等生物学特性进行了系统研究。采用固体硫酸铵盐析法和层析技术提取拟态弧菌HX-4菌株外毒素,所得外毒素具有酪蛋白酶、明胶蛋白酶、溶血素等多种毒性酶活性、细胞毒性(HEp-2)、肠毒性和致死性等生物学特性,TC ID50为0.025μg,对中华绒螯蟹的半数致死量(LD50)为1.40μg。  相似文献   

2.
中华绒螯蟹“腹水病”及“抖抖病”并发病病原的研究   总被引:49,自引:4,他引:45  
于1998~1999年对中华绒螯蟹主要细菌性疾病“腹水病”、“抖抖病”并发病病原进行研究。结果表明经细菌学鉴定6株病原菌,其中5株为嗜水气单胞菌(Aeromonas hydrophila),1株为拟态弧菌(Vibrio mimicus),用细菌人工感染蟹,其LD  相似文献   

3.
中华绒螯蟹免疫因子—溶菌酶的初步研究   总被引:9,自引:3,他引:6  
研究了在自然状态下中华绒螯蟹成蟹血淋巴和大眼幼体组织匀浆上清液中溶菌酶的活性。结果表明,在中华绒螯蟹成蟹血淋巴中均检测出溶菌酶的活性,为(0.0286±0.0081)活力单位(n=30),而在中华绒螯蟹大眼幼体组织匀浆上清液中亦检测到溶菌酶的活性,为(0.0318±0.0073)活力单位(n=4)。  相似文献   

4.
蟹源致病性拟态弧菌的粘附及侵袭特性   总被引:4,自引:1,他引:3  
胡守奎 《水产学报》2004,28(5):541-546
病原菌对机体的致病作用是由其产生的各种毒力因子共同作用的结果,其中病原菌对组织细胞或粘膜的表面粘附是造成机体感染的首要条件。病原菌的粘附因子主要包括菌毛粘附素和其它非菌毛粘附素(如鞭毛、外膜蛋白和血凝素等),其中以菌毛介导的病原菌对组织细胞的粘附是细菌在体内定居、增殖释放毒力因子发挥致病作用的关键。为了揭示拟态弧菌HX 4的致病机理,以经典粘附模式细胞HEp 2细胞作为体外细胞模型,探讨蟹源致病性拟态弧菌HX 4株的粘附特性以及受体物质和抗全菌抗体对细菌粘附作用的影响,同时采用庆大霉素清洗裂解培养法测定该菌对HEp 2细胞的侵袭力。结果显示,HX 4菌株能粘附HEp 2细胞,对HEp 2细胞具有侵袭力。细菌对HEp 2细胞的粘附方式为集聚性粘附,最佳粘附时间为1h,甘露糖和抗体能显著抑制该菌的粘附,表明HEp 2细胞上含有甘露糖样受体。该菌的粘附素除了主要是菌毛外,可能还含有鞭毛、外膜蛋白、血凝素等多种成分。  相似文献   

5.
中华绒螯蟹超氧化物歧化酶的初步研究   总被引:5,自引:0,他引:5  
对自然状态下长江水系的中华绒螯蟹成蟹血淋巴和大眼幼体组织匀浆上清液中超氧化物歧化酶(SOD)的活性进行了初步研究。结果表明,在中华绒螯蟹成蟹血淋巴中均检测出超氧化物歧化酶的活性,为182.96±45.66 U/mL(n=29),而在中华绒螯蟹大眼幼体组织匀浆上清液中亦检测到超氧化物歧化酶的活性,为94.29±15.65 U/mL(n=4)。超氧化物歧化酶在河蟹的自身防御系统中起着重要的作用。  相似文献   

6.
中华绒螯蟹血淋巴钙离子和17_雌二醇浓度与性早熟的关系   总被引:9,自引:2,他引:7  
吴嘉敏 《水产学报》2001,25(2):112-115
中华绒螯蟹的性腺发育与血淋巴钙离子浓度相关.性早熟雌性扣蟹(一秋龄)血淋巴钙离子浓度为21.25±11.89mmol@L-1,明显高于正常发育的13.70±1.17mmol@L-1;雄性扣蟹(一秋龄)则相反,性早熟扣蟹血淋巴钙离子浓度为16.33±1.38mmol@L-1,低于正常发育的20.13±2.37mmol@L-1.二秋龄雄性成蟹的血淋巴钙离子指标与性早熟雄性扣蟹相当,无显著差异.随着个体的生长发育,雌性中华绒螯蟹血淋巴17β-E2浓度逐步提高,正常发育扣蟹为0.15±0.05pg@mL-1,性早熟扣蟹为0.59±0.15ng@mL-1,二秋龄成蟹为2.31±1.08pg@mL-1.  相似文献   

7.
为明确江苏苏州某养殖场中华绒螯蟹(Eriocheir sinensis)死亡病因,本研究从病蟹肝胰腺组织中分离到优势生长菌,对分离菌进行致病性、形态与生理生化特征及gyrB基因同源性与系统发育分析。结果显示:分离菌为豚鼠气单胞菌(Aeromonas caviae),分离菌SHZ1对中华绒螯蟹半数致死量(LD50)为1.6×106 CFU/mL,表明分离株可以引起中华绒螯蟹死亡,确定豚鼠气单胞菌是此次造成中华绒螯蟹出现大规模死亡的病原。为进一步明确分离菌SHZ1毒力携带基因情况,对分离菌进行热敏蛋白酶(eprCAI)、溶血素(hly)、弹性蛋白酶(ahpB)、外膜蛋白(ompA)、胆固醇酰基转移酶(gcaT)和鞭毛蛋白(flgN、flgM、flgA、flaH)共9种毒力基因进行检测,结果表明分离菌携带以上9种毒力基因。耐药性检测结果表明,分离菌对头孢唑啉、万古霉素、苯唑西林、青霉素G、哌啦西啉、氨苄西林等9种药物耐药。  相似文献   

8.
丁皓  栗阳 《河北渔业》2005,(3):6-9,26
通过研究大豆浓缩蛋白(SPC)对中华绒螯蟹生长的影响,来对大豆浓缩蛋白在中华绒螯蟹养殖饵料中替代鱼粉的前景进行了评估。在为期5 0d的实验饲养期间,我们用六组含有不同含量大豆浓缩蛋白的鱼粉饵料在(2 4±1)℃的温度下分别饲喂中华绒螯蟹,并且从生长情况和身体组成两方面进行了科学的研究。结果显示用全鱼粉饵料(对照组)和含有11% ,2 2 % ,33% ,4 4 %和5 6 %的SPC的饵料喂养的中华绒螯蟹生长情况不同。前五组饵料喂养的中华绒螯蟹生长情况没有显著的差异,而鱼粉被SPC完全替代的饵料对生长有抑制作用。基于实验各项结果,SPC替代鱼粉的合适比率大约为37.93%~5 6 .89%。  相似文献   

9.
用α-苯基苯并吡喃作为饲料添加剂饲喂中华绒螯蟹(Eriocheir sinensis)10 d后,测定了其对中华绒螯蟹血淋巴细胞中相关免疫因子的影响。实验设3个α-苯基苯并吡喃添加重复组,分别为A组(2 mg/kg)、B组(4 mg/kg)、C组(6 mg/kg)和1个对照重复组(0 mg/kg)。结果表明:α-苯基苯并吡喃添加剂量为4 mg/kg(B组)可显著地提高中华绒螯蟹血淋巴细胞中酚氧化酶(PO)、溶菌酶(LSZ)和超氧化物歧化酶(SOD)的活力(P<0.05),说明具有生物活性的α-苯基苯并吡喃可刺激中华绒螯蟹机体免疫相关酶活性的提高。  相似文献   

10.
中华绒螯蟹血清凝集素的生物学特性   总被引:2,自引:0,他引:2       下载免费PDF全文
将中华绒螯蟹(Eriocheir sinensis)血清凝集素与动物(鳖、鲫鱼、鸡、鸽、兔、鼠、人A、B、O型)红细胞和细菌(八叠球菌、嗜水气单胞菌、短小芽孢杆菌、大肠杆菌、葡萄球菌、假单胞菌和拟态弧菌)进行凝集反应。结果表明,中华绒螯蟹血清凝集素有明显的选择性,与小白鼠红细胞和八叠球菌的凝集活性最高(P<0.01)。血清凝集价在蟹个体之间变化范围较大,性别之间无显著差异(P>0.05)。10 mmol/L的CaCl2和300 mmol/L的NaCl不影响凝集素与小鼠红细胞和细菌的凝集活性,600 mmol/L的NaCl可降低其活性。pH 5~9不影响蟹凝集素活性,但400 mmol/L的EDTA在pH 7.0可部分抑制其活性,100 mmol/L的EDTA在pH 5.0则可完全抑制其活性。在细菌刺激下,中华绒螯蟹血清凝集素活性在2 d达到峰值,随后逐步缓慢下降。接种细菌(八叠球菌)的数量(3.0×109~9.0×109)显著影响血清凝集素的产生(P<0.05),而环境水温度(18~30℃)和蟹体质量(35~80 g)的影响则不显著(P>0.05)。  相似文献   

11.
12.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

13.
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.  相似文献   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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.  相似文献   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

17.
18.
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.  相似文献   

19.
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.  相似文献   

20.
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).  相似文献   

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