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

Transducer and base compliance alter the in situ 6 dof force measured from muscle during an isometric contraction in a multi-joint limb.

Although musculoskeletal models are commonly used, validating the muscle actions predicted by such models is often difficult. In situ isometric measurements are a possible solution. The base of the skeleton is immobilized and the endpoint of the limb is rigidly attached to a 6-axis force transducer. Individual muscles are stimulated and the resulting forces and moments recorded. Such analyses generally assume idealized conditions. In this study we have developed an analysis taking into account the compliances due to imperfect fixation of the skeleton, imperfect attachment of the force transducer, and extra degrees of freedom (dof) in the joints that sometimes become necessary in fixed end contractions. We use simulations of the rat hindlimb to illustrate the consequences of such compliances. We show that when the limb is overconstrained, i.e., when there are fewer dof within the limb than are restrained by the skeletal fixation, the compliances of the skeletal fixation and of the transducer attachment can significantly affect measured forces and moments. When the limb dofs and restrained dofs are matched, however, the measured forces and moments are independent of these compliances. We also show that this framework can be used to model limb dofs, so that rather than simply omitting dofs in which a limb does not move (e.g., abduction at the knee), the limited motion of the limb in these dofs can be more realistically modeled as a very low compliance. Finally, we discuss the practical implications of these results to experimental measurements of muscle actions.

Asymptotic stability for time-variant systems and observability: Uniform and nonuniform criteria

This paper presents some new criteria for uniform and nonuniform asymptotic stability of equilibria for time-variant differential equations and this within a Lyapunov approach. The stability criteria are formulated in terms of certain observability conditions with the output derived from the Lyapunov function. For some classes of systems, this system theoretic interpretation proves to be fruitful since - after establishing the invariance of observability under output injection - this enables us to check the stability criteria on a simpler system. This procedure is illustrated for some classical examples.

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)

Histone H2A Has a Novel Variant in Fish Oocytes

Histone variants and their modification have significant roles in many cellular processes. In this study, we identified and characterized the histone H2A variant h2af1o in fish and revealed its oocyte-specific expression pattern during oogenesis and embryogenesis. Moreover, posttranslational modification of H2af1o was observed that results from phosphorylation during oocyte maturation. To understand the binding dynamics of the novel core histone variant H2af1o in nucleosomes, we cloned ubiquitous gibel carp h2afx as a conventional histone control and investigated the dynamic exchange difference in chromatin by fluorescence recovery after photobleaching. H2af1o has significantly higher mobility in nucleosomes than ubiquitous H2afx. Compared with ubiquitous H2afx, H2af1o has a tightly binding C-terminal and a weakly binding N-terminal. These data indicate that fish oocytes have a novel H2A variant that destabilizes nucleosomes by protruding its N-terminal tail and stabilizes core particles by contracting its C-terminal tail. Our findings suggest that H2af1o may have intrinsic ability to modify chromatin properties during fish oogenesis, oocyte maturation, and early cleavage.

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.

The first study on the effects of microcystin-RR on gene expression profiles of antioxidant enzymes and heat shock protein-70 in Synechocystis sp PCC6803

Microcystins are heptapeptide toxins produced by cyanobacteria. Microcystin-RR(MC-RR) is a common variant among the 80 variants identified so far. There have been many investigations documenting the toxic effects of microcystins on animals and higher plants, but little is known on the toxic effects of microcystins on algae, especially at molecular level. We studied the effects of MC-RR on gene expression profile of a few antioxidant enzymes and heat shock protein-70 (Hsp70) in Synechocystis sp. PCC6803. After two days post-exposure, a high dose toxin (5 mg/l, about 4.8 x 10(-3) mM) significantly increased expression levels of the genes gpx1, sodB, katG, acnB, gamma-TMTand dnaK2, while a relatively low dose toxin (1 mg/l, about 9.63 x 10(-4) mM) induced a moderate and slow increase of gene expression. Our results indicate that MC-RR could induce the oxidative stress in Synechocystis sp. PCC6803 and the increase in gene expression of antioxidant enzymes and Hsp70 might protect the organism from the oxidative damage. in addition, cell aggregation was observed during the early period of exposure, which might be a specific oxidative stress reaction to MC-RR. (C) 2008 Elsevier Ltd. All rights reserved.

Design and performance analysis of a 6 MW medium-speed Brushless DFIG

The paper presents the design and performance analysis of a 6 MW medium-speed Brushless Doubly-Fed Induction Generation (Brushless DFIG) for a wind turbine drivetrain. Two machines with different frame sizes have been designed to show the flexibility of the design procedure. The mediumspeed Brushless DFIG in combination with a two stage gearbox offers a low-cost, low-maintenance and reliable drivetrain for wind turbine applications.