6种常用渔药对厚颌鲂鱼苗的急性毒性试验

在水温29~30℃条件下,用硫酸铜与硫酸亚铁合剂(比例5:2)、高锰酸钾、晶体敌百虫、强氯精、溴氯菊脂、甲醛共6种药物对厚颌鲂(Megalobrama pellegrini)鱼苗进行急性毒性试验。试验结果显示,6种药物48h的半致死浓度分别为5.78、6.50、4.90、2.55、0.042、120mg/L,安全浓度分别为0.445、0.528、0.268、0.190、0.003、7.500mg/L,厚颌鲂鱼苗对药物敏感性比一般鱼类高,实际用药时应根据具体情况确定用药时间和用药量,溴氯菊脂不宜作为治疗药物

蛙虹彩病毒一个晚期基因的鉴定

从沼泽绿牛蛙虹彩病毒(Rana gryliovirus,RGV)基因组中克隆了十四烷基化膜蛋白(myristylated membrane protein,MMP)基因的全部编码区,序列分析表明,RGVmmp基因全长972 bp,编码一个长为323 aa,分子量为35×103的蛋白.氨基酸同源性比对分析,与同为蛙病毒属的其他病毒的相应蛋白同源性都在64%以上.构建重组表达载体,进行了原核表达,获得一条约53×103的融合蛋白,并制备出抗血清.通过RT-PCR和Westernblot分析确定了RGV感染过程

长吻和异育银鲫对玉米淀粉利用差异的比较研究

在同一实验条件下,通过8周生长实验比较研究了不同玉米淀粉含量的饲料对长吻和异育银鲫生长、饲料利用和鱼体组成的影响,以探讨肉食性和杂食性鱼类对玉米淀粉利用的差异。长吻的实验饲料是5种等氮等脂、玉米淀粉含量分别为0、5%、10%、15%和20%的半精制饲料。异育银鲫的实验饲料是5种等氮等脂、玉米淀粉含量分别为6%、12%、18%、24%和30%的半精制饲料。每天饱食投喂鱼两次。实验结果表明:对于长吻,玉米淀粉含量为5%和10%饲料组的特定生长率显著高于另外3组(Duncan s多重比较,P<0.05)。

鲤鱼3个亚种线粒体DNA ND5/6区段的PCR-RFLP分析及亚种间分子标记的确立

从鲤鱼3个亚种(Cyprinus carpio carpio,Cyprinus carpio haematopterus和Cyprinus carpiorubrofuscus)中选出具代表性的品系共10个,运用PCR方法,扩增出2.4 kb的mtDNA ND5/6区段.共用9种限制性内切酶进行酶切分析,结果表明,每个亚种拥有一种单倍型,有4种限制性内切酶(Dde I,Hae III,Taq I和Mbo I)酶切后产生了能将3个亚种区分开来的诊断性限制性酶切位点.可利用其作为鉴定3个亚种的遗传标记和遗传育种

6种累枝虫(Epistylis)rRNA基因18S-ITS1序列及其分子系统发育关系

建立了由采自自然界中的样品、不经实验室培养而直接用于大核DNA提取和PCR反应的原位（in situ）方法;在此基础上,测定并比较了6种累枝虫（Epistylis wenrichi,E.urceolata,E.chrysemydis,E.plicatilis,E.hentscheli,E.galea）的18S-ITS1序列,结果显示:E.wenrichi,E.urceolata,E.chrysemydis,E.plicatilis和E.hentscheli间18S和ITS1区序列的碱基相似性很高,而它们与

鲤科鱼类6个正反交人工异源三倍体胚胎的染色体变化及其发育命运

采用静水压休克保留第二极体的方法,在鲤(♀)×鲢(?)、鲫(♀)×鲢(?)、白鲫(♀)×鲢(?)和鲢(♀)×鲤(?)、鲢(♀)×鲫(?)、鲢(♀)×白鲫(?)6个正反交组合中都诱导出了异源三倍体,但只有正交鲤(♀)×鲢(?)、鲫(♀)×鲢(?)和白鲫(♀)×鲢(?)3个处理组中整倍性的异源三倍体胚胎才有可能正常发育,孵化出苗;而反交鲢(♀)×鲤(?)、鲢(♀)×鲫(?)和鲢(♀)×白鲫(?)3个处理组中的异源三倍体胚胎在发育过程中不断发生染色体排除和丢失,形成非整倍体而死亡,只有少数雌核发育二倍体鲢才能孵

果糖1,6-二磷酸酯酶的代谢调控

<正> 果糖1,6-二磷酸酯酶(FBPase 1)在生物体内糖异生代谢途径中起着重要的作用。当二价金属离子存在时,它催化果糖1,6-二磷酸(Fru-1,6-P_2)水解生成果糖6-磷酸(Fru-6-P)和无机磷。它是一个由4个相同亚单位构成的蛋白质,其亚单位分子量约为35 000～40 000。FBPase 1可被蛋白水解酶降解修饰,使其最适pH从7.5变为9.2。该酶受AMP及果糖2,6-二磷酸(Fru-2,6-P_2)

Waterborne exposure to fluorotelomer alcohol 6:2 FTOH alters plasma sex hormone and gene transcription in the hypothalamic-pituitary-gonadal (HPG) axis of zebrafish

Fluorotelomer alcohols (FTOHs) have shown estrogenic activity in vitro and in vivo, but the mechanism of this activity is not known. In this study, 18-week-old zebrafish (Danio rerio) were exposed to 0, 0.03, 0.3 and 3.0 mg/l 1H, 1H, 2H, 2H-perfluorooctan-1-ol (6:2 ETCH) for 7 days, and the effects on plasma sex hormone levels were measured followed by use of real-time PCR to examine selected gene expression in hypothalamic-pituitary-gonadal (HPG) axis and liver. Exposure to 6:2 FTOH significantly increased plasma estradiol (E2) and testosterone (T) levels in both males and females. Furthermore, the ratio of T/E2 was reduced in females while increased in males. In females, the increase of E2 was accompanied by up-regulated hepatic estrogenic receptor alpha (ER alpha) and vitellogenin (VTG1 and VTG3) expression. In males, the elevation of the T level is consistent with the up-regulation of cytochrome P450 c17 alpha-hydroxylase, 17, 20-lase (CYP17) and the down-regulation of cytochrome P450 aromatase A (CYP19A). The present study demonstrated that waterborne exposure to 6:2 FTOH alter plasma sex hormone levels and the ratio of T/E2, as well as the transcriptional profiles of some genes in the HPG axis and liver. The results suggested that FTOHs may disturb fish reproduction through endocrine disrupted activity. (C) 2009 Elsevier B.V. All rights reserved.

RNAi suppression of zebrafish peptidoglycan recognition protein 6 (zfPGRP6) mediated differentially expressed genes involved in Toll-like receptor signaling pathway and caused increased susceptibility to Flavobacterium columnare

In Drosophila, Toll signaling cascade, which resembles the mammalian Toll-like receptor (TLR)/IL-1R signaling pathways and regulates the expression of anti-microbial peptide genes, mainly relies on peptidoglycan recognition proteins (PGRPs) for the detection of bacterial pathogens. To explore the effect of zebrafish peptidoglycan recognition protein 6 (zfPGRP6) on Toll-like receptor signaling pathway, RNA interference (siRNA) and real time quantitative PCR (RQ-PCR) methods were used to identify differentially expressed genes regulated by zfPGRP6. The target genes included TLR2, TLR3, TLR5, TLR7, TLR8, IL1R, Sterile-alpha and Armadillo motif containing protein (SARM), myeloid differentiation factor 88 (MyD88) and nuclear factor (NF)-kappa B2 (p100/p52). The results of RQ-PCR showed that RNAi-mediated Suppression of zfPGRP6 significantly down-regulated the expression of TLR2, TLR5, IL1R, SARM, MyD88 and p100/p52. The expression of beta-defensin-1 was also down-regulated in those embryos silenced by zfPGRP6. In challenge experiments to determine the anti-bacterial response to Gram-negative bacteria, RNAi knock-down of zfPGRP6 markedly increased susceptibility to Flavobacterium columnare. (C) 2008 Elsevier B.V. All rights reserved.

PCR-RFLP analysis of mitochondrial DNA ND5/6 region among 3 subspecies of common carp (Cyprinus carpio L.) and its application to genetic discrimination of subspecies

Mitochondrial DNA ND5/6 region was studied by PCR-RFLP analysis among ten representative strains belonging to three subspecies (Cyprinus carpio carpio, Cyprinus carpio haematopterus and Cyprinus carpio rubrofuscus) of common carp (Cyprinus carpio L.). A total of 2.4 kb fragment was amplified and subjected to restriction endonuclease analysis with nine restriction endonucleases subsequently. The results indicated that each subspecies owned one hyplotype and four restriction enzymes (Dde I, HaeIII, Taq I and Mbo I) produced diagnostic restriction sites which could be used for discriminating the three subspecies and as molecular genetic markers for assistant selective breeding of common carp.

Isolation by phage display and characterization of a single-chain antibody specific for O-6-methyldeoxyguanosine

New approaches of making single chain Fv antibodies against O-6-methyl-2'-deoxyguanosine (O(6)MdG) have been demonstrated by using the phage antibody display system. Using O(6)MdG as an antigen, 21 positive clones were identified by ELISA from this library, one of which, designated H3, specifically binds to O(6)MdG with high affinity. The H3 scFv antibody has an affinity constant (K-aff) of 5.94 x 10(11)(mol/L)(-1). H3 scFv has been successfully used to detect O-6 MdG in DNA hydrolyses from yeast or E. coli cells treated with a DNA methylating agent. To our knowledge, this is the first report of the selection of a specific scFv against DNA adducts. The results demonstrate the potential applications of the phage display technology for the detection of DNA lesions caused by mutagens and carcinogens.

Persistence of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in Ya-Er Lake area, China

The concentrations of polychlorinayed dibenzo-p-dioxins and dibenzofurans (PCDD/F) in surface sediment, soil, human hair, acid fish muscle from Ya-Er Lake area, China, were analyzed. The results showed that there were very high concentrations of PCDD/F existing in these samples. The results also indicated that Ya-Er Lake, which received a large amount of waste water from a nearby chloroalkali plant, was heavily polluted by PCDD:F. The present study demonstrated that those congeners, which possess at least three chlorine atoms in the lateral position with a fourth chlorine atom in the neighborhood bond of the third single chlorine atom, such as 1,2,7,8-TCDF and 2,3.6,7-TCDF, were very resistant to biodegradation due to the "neighbor effect" of every two chlorine atoms. The present study suggested that human hair may be a suitable alternative bioindicator for detecting PCDD/F exposure. (C) 2001 Elsevier Science Ltd. All rights reserved.