正烷酵母饵料致突变性的研究

本试验用鼠伤寒沙门氏菌组氨酸缺陷型——哺乳动物肝微粒体酶测试系统(Ames’Test)，对正烷酵母饵料浸出液的非极性树脂XAD-2吸附物进行检测，以查明其是否具有致突变或致癌作用。结果表明，正烷酵母对菌株TA98及TA100有致突变作用，由此证明这种饵料中存在着引起DNA移码突变和碱基对置换突变的化合物，故这种酵母在被用作鱼类饵料或其他动物饲料之前，还应作进一步研究，防止其对环境的污染和其他潜在的危害性。     

锯缘青蟹蜕皮抑制激素cDNA的分子克隆及其表达分析

根据近缘种类同源序列设计简并引物,采用逆转录聚合酶链式反应(RT—PCR)技术,首次扩增获得锯缘青蟹(Scylla serrata)眼柄组织中编码蜕皮抑制激素(MIH)成熟肽全长cDNA序列及部分信号肽序列。将该序列克隆到pUCm—T载体上进行序列测定。结果表明,编码锯缘青蟹MIH成熟肽的cDNA由234个碱基组成,由此推测MIH成熟肽含78个氨基酸残基。该序列不仅与其它短尾类甲壳动物的MIH氨基酸序列具有高度的同源性(79％～9l％),还与该激素同一家族的性腺抑制激素、大颚器抑制激素的氨基酸序列具有较高的相似性。RNA斑点杂交结果显示,MIH基因在眼柄神经节及脑组织中均有表达,而在肌肉、中肠腺中不表达。     

温度对锯缘青蟹幼体存活与发育的影响

锯缘青蟹溞状幼体生长发育的适温范围为25—30℃。在该范围内,随着幼体发育,其生存最适温度逐渐上升。各期溞状幼体的发育均随温度的提高而加快,从孵化至第一次变态,30℃时平均发育时间比 25℃时短 6天。温度对溞状幼体的变态过程亦有明显影响,水温大于或达到 30℃时不利于变态的进行,但变态后的大眼幼体对高温适应力增强,35℃时仍可正常生长发育。不同批孵化的幼体在相同温度下存活与发育有明显差异。在对后期溞状幼体相对不适的 25℃下,溞状幼体发育期数变异的出现率较高。     

光照强度对拟穴青蟹幼体生长及能量收支的影响

以拟穴青蟹为研究对象,研究了1 000 lx、3 000 lx、5 000 lx、7 000 lx、9 000 lx五组光照强度对其溢状幼体蜕皮、生长及能量收支的影响.结果表明:(1)1 000 lx试验组幼体从第4期潘状幼体(Z<,4>)阶段起即期变态成活率明显下降,全部实验幼体最终均不能变态为大眼幼体(M);5 0...     

恩诺沙星及其代谢产物环丙沙星在拟穴青蟹体内的药代动力学

采用高效液相色谱法,研究盐度33条件下恩诺沙星口灌和肌肉注射给药(剂量10 mg/kg)后,恩诺沙星及其代谢物环丙沙星在拟穴青蟹体内的药代动力学和组织分布。血淋巴和组织中药代动力学参数采用基于统计矩原理的非房室模型进行计算。恩诺沙星口灌和肌肉注射拟穴青蟹给药后,血药达峰快,分别为0.5 h和1 min,达峰浓度分别为12.90和31.86 μg/mL,曲线下面积(AUC)分别为216.1和816.8 μg/(mL·h)。恩诺沙星在拟穴青蟹组织中分布较广,口灌给药下肌肉和肝胰腺AUC分别为445.9和817.6 μg/(g·h),肌肉注射给药下的AUC分别为554.7和2 573.7 μg/(g·h)。与其它水产动物相比,恩诺沙星在拟穴青蟹体内消除速度为中等水平,口灌和肌肉注射恩诺沙星后血药消除半衰期(t_1/2z)分别为26.45和57.02 h,总体清除率(CL_z)分别为0.054和0.012 L/(h·kg)。恩诺沙星在拟穴青蟹体内代谢生成环丙沙星的量较少,口灌给药下血淋巴、肌肉和肝胰腺的AUC_CIP/AUC_ENR分别为6.66%、3.66%和4.78%,肌肉注射给药下,其相应值分别为4.16%、7.24%和1.48%,在拟穴青蟹体内起药效作用仍是以恩诺沙星为主。以C_max/MIC、AUC_0-24/MIC评价恩诺沙星在青蟹体内的药效作用,建议给拟穴青蟹以10 mg/kg剂量每隔24小时投喂一次恩诺沙星,对弧菌引起的细菌性疾病具有较好的防治效果。     

锯缘青蟹精子入卵过程的扫描电镜观察

利用扫描电镜详细观察了锯缘青蟹精子入卵的过程。精子以其核突起附着在卵膜上，并迅速发生顶体反应。顶体反应时，顶体囊外翻，顶体管前伸，精子核辐射臂收缩，并拖至顶体囊的后部。顶体管迅速穿过卵黄膜，携带核物质一同进入卵子。锯缘青蟹为多精着卵，数精入卵。本文同时探讨了精子顶体反应机制以及受精过程卵子的作用。     

拟穴青蟹卵巢蛋白质双向电泳的样品制备方法

为探索适用于拟穴青蟹卵巢蛋白质双向电泳的样品制备方法,比较了TCA/丙酮沉淀法和3种裂解液抽提法对总蛋白的提取效果,4种方法分别得到133、369、306和417个蛋白点。采用裂解液Ⅲ(7 mol/L尿素、2 mol/L硫脲、4% CHAPS、40 mmol/L Tris-base、65 mmol/L DTT、2% IPG Buffer、Protease in hibitor cocktail、1 mmol/L EDTA)提取蛋白所得图谱效果最好,背景清晰,蛋白点最多。     

Parentage determination of the mud crab Scylla paramamosain using microsatellite markers

This study evaluated the properties of nine Scylla paramamosain microsatellite loci screened by us previously for inclusion in a parentage assignment marker suite. These nine highly polymorphic markers (mean He=0.847 and PIC=0.830) were determined as being suitable for parentage assignment. Simulations based on allele frequency data from 15 known maternal families (165 individuals) demonstrated that at least four loci were required to assign >95% of offspring to maternal parents with 95% confidence. In actual parentage assignments, all progenies were assigned to the maternal parents with six or more loci, which was similar to the simulation predictions. Our results suggest that this set of microsatellites provide a powerful and efficient tool for identifying pedigree information for selective breeding programmes of S. paramamosain.     

Effect of dietary cholesterol levels on growth performance,body composition and gene expression of juvenile mud crab Scylla paramamosain

A 56‐day feeding trial was conducted to investigate the effect of dietary cholesterol (CHOL) levels on growth performance, body composition and gene expression of juvenile mud crab (Scylla paramamosain). Four isonitrogenous and isoenergetic diets were formulated with 0.4%, 0.8%, 1.2% and 1.6% CHOL supplemented, and the final dietary CHOL concentrations were 0.72%, 1.11%, 1.49% and 1.83% respectively. Each dietary treatment was performed with three replicates (28 crabs per replicate, initial body weight 0.04 g). At the termination of the experiment, although the survival had no statistic difference in all treatments, the mud crabs fed the lowest CHOL diet had the lowest survival rate. The weight gain (WG) of mud crab significantly increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL level further increased. The total‐cholesterol (T‐CHOL) content in whole body had an increasing trend with the dietary CHOL level increased. Besides, dietary CHOL supplement generally increased the hepatic superoxide dismutase (SOD) activity, and the mud crabs fed diets CHOL1.11 and CHOL1.49 showed significantly higher value than those fed other diets. The hepatic aspartate aminotransferase (AST) activity decreased slightly with dietary CHOL level up to 1.11% and then significantly increased with CHOL level further increased. The mRNA expression of ecdysone receptor (EcR) gene in the eyestalk obviously increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL further increased. These results suggested that about 1.11% dietary CHOL seem fulfil to maintain good growth performance and healthy condition for juvenile S. paramamosain.     

氨氮对拟穴青蟹的急性毒性及对其血清免疫相关酶活力的影响

采用静水法研究氨氮对拟穴青蟹(Scylla paramamosain)的急性毒性及在氨氮初始浓度分别为0(C0,对照组)、10(C10组)、20(C20组)、30(C30组)、40(C40组)、50 mg/L(C50组),胁迫时间分别为0、6、24、48、72 h的条件下对其血清中碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、溶菌酶(LZM)、超氧化物歧化酶(SOD)和酚氧化酶(PO)活力的影响。结果显示,总氨氮对拟穴青蟹24 h和48 h的半致死浓度分别为104.793、66.124 mg/L,安全浓度为7.90 mg/L,非离子氨对拟穴青蟹24 h和48 h的半致死浓度分别为8.396、5.298 mg/L,安全浓度为0.63 mg/L。在胁迫6、24、48与72 h时,各实验组的LZM活力均显著低于对照组(P0.01)。相较于对照组,C10、C20及C40组在24 h的AKP、ACP活力均显著升高(P0.05)。C20组在24 h的SOD活力则显著低于其他胁迫时间点(P0.05)。胁迫72 h时,C30、C40及C50组的PO活力显著高于对照组(P0.05)。该实验条件下,不高于40 mg/L的氨氮可在24 h内使拟穴青蟹血清中的AKP与ACP活力显著升高,而50 mg/L的氨氮则对其具有抑制作用;各实验组浓度氨氮均在72 h内对拟穴青蟹血清中的LZM活力具有显著的抑制作用,对PO活力具有明显的刺激作用,对SOD活力无显著影响。