大西洋牙鲆胚胎发育的形态观察

为了掌握大西洋牙鲆早期发育的规律,2005年2月在实验室利用显微镜和显微数码摄像显示系统观察测量拍摄大西洋牙鲆受精卵胚胎发育和初孵仔鱼的形态特征,描述并记录其发育过程和时间。大西洋牙鲆的卵为球形游离的浮性卵,卵径平均977μm,单油球,偶见2或3油球,油球径180μm。在水温19~20.8℃时孵化,大约受精后50 min胚盘形成,5 h30 min进入囊胚期,8 h后进入原肠胚期,21 h左右进入胚体器官分化期,40 h后尾部游离,心跳开始,胚体搐动,51~52 h孵出。实验表明,大西洋牙鲆受精卵的孵化进度与水温相关。孵化时间(Ht)与水温(t/℃)关系方程为Ht=3 154.8t-1.333 6(R2=0.925 4)。     

牙鲆野生群体与养殖群体的遗传多样性分析

利用AFLP技术对荣成野生群体和养殖群体牙鲆进行遗传多样性分析和比较。实验采用 7对引物组合在 2个群体中共扩增出 797个位点 ,其中多态位点数为 43 3个 ,占总位点数的 5 4.2 7%。各引物组合在 2个群体中的扩增位点数目和多态位点比例有较大不同 ,但养殖群体的总扩增位点数和多态位点比例均低于野生群体 ,野生群体和养殖群体的平均多态位点率分别为 46.18%和 40 .0 7% ,其中 ,E3 8M 5 0引物组合在两群体中扩增的多态位点比例差异显著 (P <0 .0 5 )。养殖群体中低频位点明显减少而隐性纯合基因位点显著增加。群体遗传结构分析表明 ,两群体间的遗传距离比较小 ,群体遗传结构相似 ,说明养殖群体尚没有形成自己独立的遗传结构。     

Isolation of differentially expressed genes from contaminant exposed European flounder by suppressive, subtractive hybridisation

Commercially farmed European flounder (Platichthys flesus) were treated with benzo[a]pyrene or cadmium under controlled laboratory conditions. In addition, animals were collected from the polluted Tyne and relatively clean Alde estuaries in the UK. Potential differentially expressed genes were isolated from liver tissue by means of suppressive, subtractive hybridisation. A total of 284 different mRNAs were identified as having the potential for being differentially expressed, of which 84 could be tentatively identified by homology with database sequences. These clones will form part of a flounder cDNA array for validation and future applications, with full identification being pursued for those expressed sequence tags for which differential expression can be confirmed by array technology.     

Studies on the edwardsiellosis and characterization of pathogenic bacteria from diseased flounder (Paralichthys olivaceus L.) and turbot (Scophthalmus maximus L.)

1IntroductionEdwardsiellahas been recognized as a world-wide-occurring pathogen of numerous marine fishspecies,and edwardsiellosis has been recorded in adiverse array of fish species,including chinooksalmonOncorhynchus tshawytschaL.(Amandi etal.,1982),cha…     

犬齿牙鲆幼鱼呼吸耗氧率的研究

对犬齿牙鲆幼鱼在不同环境条件下的呼吸频率、耗氧率以及窒息浮头现象进行了观测研究。结果表明:犬齿牙鲆在适宜温度范围,呼吸频率随温度的升高而加快,在适宜生长温度范围,其呼吸频率为60～100次/min。耗氧量与鱼体重正相关,二者之间的相关关系符合M=1.8469W0.8317(r=0.9116)模式。其耗氧率随温度和盐度的增加而增加,在水温20℃左右,体重108g的犬齿牙鲆24h平均耗氧率为1.6676μg/(min·g),明显低于褐牙鲆(体重69.3～151.4g)耗氧率2.68μg/(min·g)和大菱鲆(17℃体重70～110g)耗氧率3.4667μg/(min·g)的水平。其耗氧率白天为1.824μg/(min·g),夜间为1.511μg/(min·g),白天耗氧率是夜间的1 21倍,昼夜差异明显。犬齿牙鲆20℃半数死亡窒息点耗氧率为0 747mg/L,全部死亡窒息点耗氧率为0 569mg/L。