Isolation and characterization of a new species of Vibrio-Vibrio olivaceus sp.nov. from diseased flounder （Paralichthys olivaceus temminck et schlegel）

One kind of pathogenic bacteria was isolated from diseased (or dead) flounder (Paralichthys olivaceus L.) which expressed bacterial septicaemia. The phenotyic information of the 10 pure cultures was studied extensively, including morphological characteristics, colony characteristics in different media, physiological and biochemical characteristics, and the mol%G C ratio of the DNA for representative strain. The results showed that the isolates belonged to a new species of Vibrio. In addition, the representative strains have been re-checked by China Center for Type Culture Collection (CCTCC), the results were the same as ours, the examined strains were also regarded as a new species of Vibrio, and designated as Vibrio olivaceus sp.nov. by its isolated fish (Paralichthys olivaceus) based on its biological properties following Rules of International Code of Nomenclature of Bacteria. In the same time, we conducted studies on the serum homology of isolates, pathogenicity of isolates by experimental infection. The results showed that all the isolates were of serologic similarity and the isolates have strong pathogenicity to flounder. Inspection to pure cultures and isolates from liver of moribund fish from infection experiment by fluorescent antibody technique showed the feasibility of fluorescent antibody technique as an auxiliary method of examination.     

牙鲆家系的建立及早期生长比较

以东海舟山海域野生牙鲆群体为亲本,采用人工授精技术,共构建14个牙鲆家系,分别测定了各家系120日龄30个个体的全长、体长和体重,对家系间的生长和家系内的个体体重变异进行了比较。结果表明:不同家系间的全长、体长和体重的差异均极显著(P<0.01)。家系1、3、4、10、11和14为生长较快家系,按体重大小依次排列为3>10>11>1>14>4,按全长长短依次顺序为3>14>1>4>11>10。家系2内个体体重变异最大。家系3个体体重变异小,其体重平均值要高出体重最小家系35%,表现出明显的生长优势。这一研究为进一步通过家系选育方法培育适合浙江沿岸生长的优良品系奠定基础。     

Ultrastructural Observation of the Skin Chloride Celis of Japanese Flounder Paralichthys olivaceus and Turbot Scophthamus maximus Larvae

The ultrastructures of skin chloride celis in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride celis were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride celis of euryhaline fish gill. They lo-cate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying net-work of tubules. The degeneration of skin chloride celis is observed with development of Japanese flounder larvae. Skin chloride celis of turbot are less developmental than those of Japanese flounder in the same developmental stage.     

Ultrastructural Observation of the Skin Chloride Cells of Japanese Flounder Paralichthys olivaceus and Turbot Scophthamus maximus Larvae

The ultrastructures of skin chloride cells in cultured Japanese flounder and turbot larvae in metamorphosis,which grow in the same feeding conditions,are examined with a transmission electron microscope.These developed skin chloride cells were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride cells of euryhaline fish gill.They locate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels.The cytoplasm of cell is full of numerous mitochondria and a ramifying network of tubules.The degeneration of skin chloride cells is observed with development of Japanese flounder larvae.Skin chloride cells of turbot are less developmental than those of Japanese flounder in the same developmental stage.     

耐温牙鲆分子标记辅助选育研究

应用分子标记进行耐温牙鲆的辅助选育.首先应用已知的与耐温性为极显著负相关的牙鲆微卫星引物Po42对50尾牙鲆亲鱼DNA进行PCR分析,根据PCR分析结果将其分成耐温组和非耐温组.经过人工催产,耐温组的产卵量明显大于非耐温组和对照组.耐温组繁育的子代仔鱼变态率明显比非耐温组和对照组子代高.在人工增温的条件下,耐温组仔鱼成活率比非耐温组和对照组的仔鱼显著提高.本研究结果证明,牙鲆微卫星引物Po42可用于耐温牙鲆的分子标记辅助选育,同时也进一步确认其与牙鲆耐温性状具有关联性.     

野生与养殖褐牙鲆亲鱼营养学分析与繁殖力的研究

比较了野生与养殖褐牙鲆(Paralichthys olivaceus)亲鱼卵、肝脏及肌肉营养学成分及繁殖力,以分析其繁殖阶段的营养需求及繁殖力的差异.结果显示:野生未成熟、野生成熟、普通养殖与维生素A、C、E营养强化的卵中粗蛋白含量分别为69.95%、74.35%、54.69%和67.30%,粗脂肪含量分别为17.88%、16.32%、19.83%和17.11%,野生亲鱼卵中粗蛋白含量显著高于养殖亲鱼(P0.05),粗脂肪含量差异不显著(P0.05).野生未成熟亲鱼肝脏中粗蛋白含量显著高于野生成熟亲鱼和养殖亲鱼(P0.05),粗脂肪含量显著低于野生成熟亲鱼和养殖亲鱼(P0.05).野生亲鱼肌肉中粗脂肪含量显著低于养殖亲鱼(P0.05).野生未成熟、野生成熟、普通养殖和营养强化亲鱼的绝对繁殖力分别为1.88×106、2.40×106、0.68×106和1.38×106(粒),相对繁殖力分别为422、703、349和538(粒/克净体重),野生亲鱼的繁殖力显著高于养殖亲鱼(P0.05),营养强化显著提高了养殖亲鱼的繁殖力(P0.05).     

氯霉素在牙鲆体内的药代动力学及残留消除规律研究

采用高效液相色谱法测定牙鲆体内氯霉素的药物浓度,非房室模型统计矩原理分析药动学数据.结果表明:1)单次口服剂量为80 mg·kg-1的氯霉素,药物在牙鲆体内的药-时曲线呈明显双峰现象:第一次达峰时间Tmax(1)出现在2.00 h,鳃、肝、肾、血、肌的第一次达峰浓度Cmax(1)依次为15.01、11.80、10.35、8.56、5.21μg·mL-1;第二次达峰浓度Cmax(2)小于第一次的浓度Cmax(1),第二次达峰的时间Tmax(2)出现在8.00 h,药-时曲线下面积(AUC):肾、鳃、肝、血、肌分别为176.87、133.77、118.77、65.33、50.36μg·mL-1·h.消除半衰期(T1/2)为4.89-10.39 h,平均滞留时间(MRT)为8.67-17.05 h,说明氯霉素在牙鲆体内吸收较迅速,但滞留时间较长.2)连续5 d口服剂量为40 mg·kg-1的氯霉素,药物消除半衰期(T1/2)为39.40-115.50 h,说明口服氯霉素在牙鲆体内消除缓慢,残留较严重,其中以肾脏和肝脏组织中残留最明显.     

不同光照时间、强度对舟山褐牙鲆稚幼鱼摄食、生长的影响

光照时间和光照强度对舟山牙鲆稚幼鱼摄食和生长有显著的影响。(1)全黑暗和全亮试验组增长率最小,仅为5.0%和5.9%,成活率最低;光照16h和12h组幼鱼的成活率最高,均为100%,光照12h时牙鲆幼鱼摄食强度最大,幼鱼体长及其增长率均显著高于其它各组,(P<0.05);(2)光照强度为500lx时,牙鲆幼鱼日摄食强度最大,体长及其增长率均显著高于其它各组(P<0.05)。     

Subcellular localization and inductive expression of the dsRNA-dependent protein kinase PKR from Japanese flounder, Paralichthys olivaceus

The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) belongs to the eIF2α kinase family and plays a critical role in interferon (IFN)-mediated antiviral response. Recently, in Japanese flounder (Paralichthys olivaceus), a PKR gene has been identified. In this study, we showed that PoPKR localized to the cytoplasm, and the dsRNA-binding motifs (dsRBMs) played a determinative role in protein localization. In cultured FEC cells, PoPKR was detected at a low level of constitutive expression but was highly induced after treatment with UV-inactivated grass carp hemorrhagic virus, active SMRV and Poly I:C although with different expression kinetics. In flounder, PoPKR was ubiquitously distributed in all tested tissues, and SMRV infection resulted in significant upregulation at mRNA and protein levels. In order to reveal the role of PoPKR in host antiviral response, its expression upon exposure to various inducers was characterized and further compared with that of PoHRI, which is another eIF2α kinase of flounder. Interestingly, expression comparison revealed that all inducers stimulated upregulation of PoHRI in cultured flounder embryonic cells and fish, with a similar kinetics to PoPKR but to a less extent. These results suggest that, during antiviral immune response, both flounder eIF2α kinases might play similar roles and that PoPKR is the predominant kinase.     

牙鲆幼鱼饲料中锰、钴适宜添加量的初步研究

锰和钴是鱼类必需的微量元素,具有重要的生理功能.在以鱼粉为基础的牙鲆幼鱼实用饲料中分别添加不同浓度的锰或钴,投喂初始平均重量为10.03～10.87 g的牙鲆幼鱼一个月.结果表明,所有各组鱼的成活率相近.饲料添加锰0～50 mg/kg,添加量为10 mg/kg时牙鲆幼鱼生长最快,增重率达到159.4 %,比不添加组高出近一倍,添加量大于30 mg/kg则鱼的增重率明显下降.肌肉和骨骼中的锰含量随着饲料中锰添加量的增加而明显上升.而饲料中添加钴0～0.8 mg/kg,鱼的增重率、肌肉和骨骼中钴的含量虽有所上升,但并不显著.根据生长和元素在组织中的含量,初步确定了以鱼粉为基础的牙鲆幼鱼实用饲料中锰和钴的适宜添加量分别为锰10～20 mg/kg,钴0.8 mg/kg左右.