Existence of Microsatellites in Expressed Sequence Tags of Common Carp （Cyprinus carpio L. ） Available in GenBank dbEST Database

Common carp expressed sequence tags （ESTs） were analyzed for the existence of microsatellites, or simple sequence repeats （SSRs）. In the NCBI dbEST database, a total of 10612 sequences were registered before December 31, 2004. A complete search of 2-6 nucleotide microsatellites resulted in the identification of 513 SSR-containing ESTs, accounting for 4.8% of the total. Cluster analysis indicated that 73 sequences of SSR-containing ESTs fell into 27 groups and the remaining 440 ESTs were independent. A total of 467 unique SSR-containing ESTs were identified. These EST-SSRs contained a vari- ety of simple sequence types, and di- and tri-nucleotide repeats were the most abundant, accounting for 42.1% and 27.9% of the whole, respectively. Of the dinucleotide repeats, CA/TG was the most abundant, followed by GA/TC. BLASTx search showed that 38.1% of the SSR loci could be associated with genes or proteins of known or unknown function. BLASTx searches of SSR-containing ESTs also showed high frequencies （98/179） of hits on zebrafish sequences.     

高淀粉水平下精氨酸对松浦镜鲤肠道形态与功能的影响

【目的】探讨高淀粉饲料中添加精氨酸对松浦镜鲤(CyprinuscarpioL.)肠道消化酶活性及肠道形态的影响。【方法】选用初始体质量(6.84±0.02)g的松浦镜鲤360尾,随机分为5组,每组4个重复,每个重复18尾鱼。实验饲料分为5组,分别在45%水平的高淀粉饲料中添加质量分数0%、0.6%、1.2%、1.8%、2.4%的精氨酸,实验周期为8周,进行肠道消化酶和形态的测定。【结果】前、中、后肠的淀粉酶活性,各组之间没有显著差异(P> 0.05);添加2.4%精氨酸组的前肠脂肪酶活性显著高于对照组(P <0.05),中肠和后肠的脂肪酶活性各组间没有显著差异(P>0.05);前、中、后肠蛋白酶活性随精氨酸添加量的增加而增加,添加1.8%和2.4%精氨酸组的前肠和中肠蛋白酶活性显著高于对照组(P<0.05),添加2.4%精氨酸组后肠的蛋白酶活性显著高于对照组(P<0.05)。高淀粉饲料中添加Arg显著影响了肠道皱襞高度,但对肠绒毛宽度和肌层厚度没有显著影响。2.4%精氨酸组前肠皱襞高度显著高于其他各组(P <0.05),1.8%精氨酸组中肠和后肠皱襞高度显著高于对照组(P <0.05)。1.2%、1.8%和2.4%组肠体指数显著高于对照组(P <0.05),2.4%精氨酸组肠长指数显著高于对照组(P <0.05)。各组前、中、后肠肠绒毛密度没有显著差异,且排列较整齐。【结论】高淀粉饲料中添加1.8%~2.4%精氨酸可以增加松浦镜鲤肠道消化酶活性,同时改善了松浦镜鲤的肠道形态结构。