基于不同检测方法的养殖鱼类昼夜摄食节律研究进展

摄食节律是鱼类在长期演化过程中对光照、温度、饵料等周期性变动的环境条件主动适应的结果,掌握鱼类摄食节律直接关系到对养殖对象投喂时间、投喂方式、投喂频率等投喂策略的决定,继而影响饲料效率和养殖水体的污染负荷。综述了国内外养殖鱼类昼夜摄食节律检测方法的研究进展,总结分析了胃肠充塞度法、日摄食率法、自适应投喂法以及观察法这4种摄食节律研究方法的具体实施过程,比较了各自的优缺点,指出目前养殖鱼类摄食节律研究方法的局限性,并对未来养殖鱼类摄食节律的研究和应用进行了展望,旨在为已有摄食节律检测方法的优化改进以及新检测方法的提出提供参考。     

基于细胞色素b基因的鱇浪白鱼野生群体和养殖群体遗传多样性分析

为探讨鱇浪白鱼野生群体和养殖群体的遗传多样性,测定了野生群体和养殖群体共29尾鱇浪白鱼的线粒体DNA细胞色素b基因的全序列.结果显示:在所有个体1 140 bp序列中检测到31个变异位点,其中28个转换位点,3个颠换位点,发现21种单倍型.养殖群体的核苷酸多样性指数(0.003 38)和单倍型多样性指数(0.980 95)高于野生群体核苷酸多样性指数(0.003 21)和单倍型多样性指数(0.934 07).野生群体和养殖群体内的遗传距离分别为0.003 39和0.003 43,群体间的遗传距离(0.003 64)略大于群体内遗传距离.分子变异分析(AMOVA)结果显示:Fst=0.064 1(P<0.01),即6.41%的变异来自群体间,93.59%的变异来自群体内,变异大多发生在群体内,野生群体和养殖群体间未发生显著的遗传分化.2个群体Tajima's D检验、Fu和Li's D与F检验均为负值,表明2个群体的检验结果均偏离中性模式,鱇浪白鱼群体可能受到群体扩张和自然选择的作用.     

不同砂质砂培漂浮育苗对烤烟烟苗及其产质量的影响

 为确定适宜的育苗用砂质基质,以草炭、蛭石和腐殖酸为材料的传统基质材料为对照,进行丽江市永胜县当地的砂质山砂、热河河砂和金砂江江砂3种砂质基质与材料对烤烟砂培育苗成苗的影响研究。结果表明：烟苗的出苗率和成苗率,金砂江江砂和热河河砂处理的与现行漂浮基质接近。壮苗率接近或超过现行漂浮苗。热河河砂低于对照2%,金砂江江砂高于对照1.7%。热河河砂和金砂江江砂的烟苗根系发育良好,地上部与地下部比例协调,烟苗生长及素质好,而砂质山砂处理稍差。3种砂质处理烟苗的指标均在壮苗要求范围内,且成本投入低于现行漂浮苗33.1%。     

大鲵的生物学特性与人工养殖技术

大鲵是我国特有的濒危两栖物种,具有很高的食用、药用价值,对于科学研究具有巨大的潜在贡献。本文对大鲵的生物学特性及人工养殖技术进行了研究,旨为这一珍稀物种的进一步保护、开发利用提供有价值的参考。     

Antimutagenicity and antiproliferative studies of lipidic extracts from white shrimp (Litopenaeus vannamei)

An organic extract from fresh shrimp (Litopenaeus vannamei) was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC) and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B(1), showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB(1) and proliferation of a cancer cell line.     

组培脱毒半夏与普通半夏田间栽培比较试验

对组培半夏与普通半夏的田间栽培进行比较研究,结果发现：C2代组培半夏较普通半夏具有更强的生长和产量优势,C3代后比较优势减弱。     

不同诱导处理后水稻悬浮细胞的活性氧变化与有关酶系的关系

以水稻（Oryza sativa L.）感病品种浙福802为材料,研究了3种不同因子处理后其悬浮细胞中活性氧及其一些抗病酶系的变化情况。结果表明：(1) 3种因子均能导致H2O2的形成和积累。XOO.75-1处理后的H2O2含量分别在0.5和6 h出现突增现象,而XOO.76-25处理只在0.5～1 h达到一个峰值。推测XOO.75-1和浙辐802间的互作属于非亲和性互     

利用高通量测序开发的熊本牡蛎微卫星标记评价野生和养殖群体的遗传多样性及通用性

利用高通量测序的方法,从熊本牡蛎基因组中开发了20对具有多态性的微卫星标记,通过微卫星标记位点比较了野生群体和养殖群体的遗传多样性。野生群体中,所有位点共扩增出330个等位基因,等位基因数(N_a)范围为6～39,平均等位基因数为16.500 0;有效等位基因数(N_e)范围为1.352 9～33.361 7,平均值9.517 2;观测杂合度(H_o)范围为0.200 0～1.000 0,平均值0.671 5;期望杂合度(H_e)范围为0.265 6～0.987 7,平均值0.832 1;ShannonWeiner指数(Ⅰ)范围为0.648 3～3.585 8,平均值2.276 9;多态信息含量(PIC)范围为0.254 5～0.969 2,平均值0.803 5,共有16个位点符合Hardy-Weinberg平衡。养殖群体中,N_a平均值为10.250 0,N_e平均值为5.843 4,H_o平均值为0.639 1,H_e平均值为0.763 6,I平均值为1.791 4,PIC平均值为0.720 7。结果显示,熊本牡蛎养殖群体的遗传多样性低于野生群体,但仍然维持在高度多态水平。研究表明,在熊本牡蛎人工繁育过程中,使用大数量的亲本进行繁育,可有效防止选育群体的遗传多样性降低,但人工选育对选育群体的遗传多样性也产生了一定的影响。另外,分析了这些引物在近缘种葡萄牙牡蛎、长牡蛎、香港牡蛎、有明牡蛎、僧帽牡蛎、咬齿牡蛎以及舌骨牡蛎中的通用性情况,发现XB1-6、XB1-39和XB1-45 3个位点在8个物种中均能扩增出目的条带,XB1-41仅能在熊本牡蛎中扩增出目的条带。     

Genetic divergence among broodstocks of Arctic charr Salvelinus alpinus in eastern Canada derived from the same founding populations

We examined the amount and distribution of molecular variation at microsatellite loci in 21 broodstocks of Arctic charr Salvelinus alpinus derived from the Fraser River, Labrador and the Nauyuk Lake, Nunavut, Canada. Our goal was to assess the amount of genetic diversity and differentiation as broodstocks are subdivided and propagated in different hatcheries and grow‐out facilities. We observed significant heterogeneity across pairs of ancestral and descendant broodstocks in the mean numbers of alleles at microsatellite loci. We detected a significant decrease in the observed heterozygosity between ancestors and descendants but the amount of decrease did not depend on either the degree of removal from the wild (number of sequential transfers) or the strain (Fraser vs. Nauyuk). Based on allele frequency distributions, there was little genetic evidence of bottlenecks during the creation of subsequent broodstock populations after the initial founding events. All broodstock samples were significantly differentiated from each other but those within the same strain were more similar to each other than to broodstocks from different strains. Broodstocks from the Nauyuk Lake broodstocks showed greater differentiation from each other than did Fraser River broodstocks, which could be attributed to differences in the number of founders.     

Quantitative structure–activity studies of insect growth regulators xiv. Three-dimensional quantitative structure–activity relationship of ecdysone agonists including dibenzoylhydrazine analogs

N-tert-Butyl-N,N′-dibenzoylhydrazines such as tebufenozide (RH-5992) mimic the action of a molting hormone, 20-hydroxyecdysone, and cause premature molting of larvae leading to their death. Previously, it was shown that one of the benzoyl moieties in dibenzoylhydrazines plays a role similar to that of the aliphatic side chain at the C-17 position of ecdysones. In the present study, N-benzoyl-N′-benzylhydrazine, N,N′-dibenzylhydrazine, and N-alkanoyl-N′-benzoylhydrazine analogs have been synthesized to compare the effects of two carbonyl groups as well as two benzene rings of dibenzoylhydrazine. The quantitative structure–activity relationship of ecdysone agonists including dibenzoylhydrazine analogs was analyzed three-dimensionally using the CoMFA (comparative molecular field analysis) procedure. The CoMFA results suggested that the two carbonyl oxygen atoms of the diacylhydrazine skeleton probably correspond to the oxygens of the 20- and 22-OH groups of ecdysones, and that the benzoyl moiety located closer to the tert-butyl group is important for retaining high activity. © 1998 SCI