Immunological and physiological validation of enzyme-linked immunosorbent assay for growth hormone of the Asian catfish, Clarias batrachus

This study describes the development and validation of competitive antigen capture enzyme-linked immunosorbent assay (ELISA) for growth hormone (GH) of the catfish, Clarias batrachus. Isolated GH was characterized first through bioassay, amino acid sequencing, immunoblotting and immunocytochemistry, and then used to raise antibody to develop ELISA. The lowest detection limit of the assay system was 0.17 ng ml⁻¹, and the standard curve had an ED₅₀ value of 0.35 ng ml⁻¹. Repeated determination of GH in a plasma pool exhibited intra- and interassay co-efficient of variation of 8.1% and 7.09% (n=5), respectively. Dose–response inhibition curves resulting from dilutions of plasma and pituitary homogenate of C. batrachus were parallel to the standard curve, while such parallelism in the case of Cyprinus carpio and H. fossilis was absent revealing no cross reaction of them in the present ELISA. In vivo effects of sGnRH, testosterone, 5-HT and morphine on plasma GH were also examined to validate the ELISA physiologically. sGnRH, testosterone and morphine increased, while 5-HT decreased GH level in a dose-dependent manner.     

涨渡湖黄颡鱼的地理标志产品保护现状与对策

我国淡水鱼类国家地理标志产品现有涨渡湖黄颡、泰山赤鳞鱼等10种。本文介绍我国淡水鱼类资源的地理标志产品保护概况,分析涨渡湖黄颡鱼的地理标志产品保护现状,探讨其地理标志知识产权保护的发展对策,并从地理标志知识产权保护模式、＂地理标志产品专用标志＂、国家推荐性标准、区域专业化发展、农业文化遗产保护、原产地域湿地环境保护等方面,提出了相关建议。     

Mechanism of fenvalerate-withdrawal-dependent recovery in metabolism of a catfish, Clarias batrachus

The effects of protein synthesis inhibitors on fenvalerate-withdrawal-dependent recovery in citrate synthase (CS), glucose 6-phosphate dehydrogenase (G6-PDH), lactate dehydrogenase (LDH), RNA, and protein of brain, liver, and skeletal muscle of Clarias batrachus were studied to explore possible mode of action of a pyrethroid insecticide at metabolic level. The administration of actinomycin D or cycloheximide inhibited partially or completely the withdrawal-dependent increase in enzyme activities, RNA, and protein contents, substantiating de novo synthesis of these macromolecules during recovery. The inhibition was more pronounced in response to cycloheximide reflecting recovery in translation process. This also suggests the possibility of fenvalerate-induced impairment of metabolism through inhibition of enzyme synthesis.     

不同脂肪酸含量及比例对黄颡鱼幼体组成影响的研究

在粗蛋白42%和粗脂肪8%的半精制饵料中,添加不同剂量的鱼油、玉米油、花生油和芝麻油,使20C:5n-3(EPA)+22C:6n-3(DHA)的含量(占总脂肪的%)和n-3/n-6比例分别为14.942,0.728;15.551,0.851;19.365,1.238;19.976,1.345和20.457,1.406。饲喂黄颡鱼(Pelteobagrus fulvidraco,Richardson)幼鱼50 d,研究了不同脂肪酸含量及比例对黄颡鱼幼鱼体组成的影响。结果表明,随着饵料中EPA+DHA的含量和n-3/n-6比例的逐渐增加,鱼体肌肉中水分含量逐渐增加,粗蛋白含量逐渐降低,肌肉中的n-3脂肪酸含量和n-3/n-6比例逐渐增加,肌肉的n-6和n-9脂肪酸含量逐渐降低。     

Seismic Behaviors of Frames in Frame Wall Structures under Rare Earthquakes on the Zone of Fortification Intensity 8 in China

To investigate the seismic behaviors of frames in frame wall structures (dual system), which may be different from those of frame structures, two frame wall structures were designed conforming to current Chinese design codes. One is a twenty four story building on the Zone of Fortification Intensity 8 (0.3g), and the other is a thirty story building on the Zone of Fortification Intensity 8 (0.2g). Then inelastic dynamic response analyses of the two structures were conducted with series of inputs of ground motions in a rare earthquake level. The seismic behaviors of the two structures were investigated preliminarily. It was found that the columns and beams of the frames in the frame wall structures did not experienced yielding under strong earthquake, while coupled beams in walls were the major energy dissipation elements with their post yielding plasticity. And the bases of some walls formed hinges as well. The reasons for the frames of dual system remained non yielding states were analyzed and discussed from the aspects of their favorable load carrying state and strengthening measures for them in dual systems in Chinese design codes. A preliminary proposal was made that it may be feasible to loosen moderately some seismic fortification measures concerning the frame in the dual system with a height exceeding 60m on the Zone of Fortification Intensity 8.     

饲料中添加苯甲酸雌二醇诱导黄颡鱼性别转化的初步研究

[目的]确定苯甲酸雌二醇诱导黄颡鱼性转化的条件.[方法]分别以浮游动物和微颗粒饲料作为激素载体,研究了添加不同浓度的苯甲酸雌二醇对黄颡鱼性转化诱导过程中成活率、雌性率以及体长的影响.[结果]浮游动物与微颗粒饲料作为载体进行投喂对黄颡鱼鱼苗成活率、雌性率和体长具有较明显差异,浮游动物组成活率为43.1％ ～66.5％,而微颗粒饲料组成活率为17.1％ ～52.1％;过高的激素浓度处理会导致死亡率升高,而过低的激素浓度处理会导致雌性率大大降低;不同载体和激素处理浓度对黄颡鱼鱼苗生长均具有明显的抑制作用.[结论]以浮游动物或微颗粒饲料为载体,苯甲酸雌二醇的最适浓度分别为150 μg/L和50 mg/kg.     

Circadian locomotor activity in Japanese sea catfish <Emphasis Type="Italic">Plotosus lineatus</Emphasis>

To find out whether or not the locomotor activity of the Japanese sea catfish, Plotosus lineatus, shows a circadian rhythmicity, the locomotor activity of this catfish was recorded in a laboratory. All of the catfish recorded (n = 20) showed a nocturnal locomotor activity rhythm under a light–dark (LD) cycle (LD 12:12). The locomotor activity started after the light was turned off, and declined during the period of darkness. In five of the six catfish we examined, locomotor activity shifted gradually over the course of 3–4 days in order to synchronize to the LD cycle after it was advanced by 6 h. Locomotor activity persisted within a constant darkness (DD) in all eight of the catfish. The average free-running period of locomotor activity under DD lasted for 24.2 ± 0.4 h (mean ± SD). Thus, the present results demonstrate that the Japanese sea catfish has an endogenous circadian oscillator entrained by an LD cycle.     

黄颡鱼源温和气单胞菌对氟苯尼考耐药性获得与消失速率研究

在离体条件下,以36℃培养48 h为1代,测定5株黄颡鱼源温和气单胞菌(Aeromonas sobri)对氟苯尼考的耐药性获得与消失速率.结果显示,试验菌株在含有氟苯尼考的药物培养基中经连续传代诱导7代后,对氟苯尼考均获得了较高且稳定的耐药性,最低抑菌浓度(MIC)值分别上升了8～64倍;将已获得高耐药性的试验菌株接种在不含药物的营养肉汤培养基中连续传代至第5代后,MIC值呈稳定状态,但耐药性的消失速率很慢,其中As-004菌株的MIC值不变,其他4株菌株的MIC值也仅下降了50％.试验结果为水产养殖中科学选药和规范用药提供了理论依据,在生产实践中具有参考价值和指导意义.     

Factors influencing the variance in expected yield on catfish farms in the United States

Analysis of data from a cross-sectional survey of 571 catfish farmers in the four major catfish-producing states in the United States showed that variability in production fell as farm size increased. Increasing pond size was associated with increasing variability in production. The variance of production was higher on operations that had watershed ponds than on operations with levee ponds.     

Advances on Structure and Function of Genomic DNA of Porcine Circovirus Type 2

Porcine circovirus type 2 (PCV2) is a disease caused by porcine circovirus, which can damage the host's immune system and exacerbate the clinical symptoms of many bacterial and viral infections.It has caused increasingly larger losses in the pig industry wordwide.The genomic DNA of PCV2 contains 11 open reading frames (ORFs) and at least seven potential ORFs-encoding proteins larger than 5 ku.However, only five virally encoded proteins, including Rep, Rep', Cap, ORF3 and ORF4, had been identified in PCV2 replication.In this review, we discussed the progress on structure and function of genomic DNA of PCV2 in order to provide insight into the scientific basis of the pathogenesis of PCV2 and prevent its infection.