963 resultados para Glycosidic linkage


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第一部分 刺参遗传连锁图谱的构建 利用AFLP和微卫星标记以一个远缘地理杂交家系为作图群体,以拟测交理论为作图策略,构建了刺参Apostichopus japonicus的雌性和雄性遗传连锁图谱。利用62对AFLP引物组合,对亲本和93个个体进行了分离分析,共得到3572个标记,其中具有多态性的标记为点数为1133个,多态性比例为31.5%。平均每个引物对产生18.3个多态片段。1133个多态性位点中,294个标记在父母本中都出现并在后代中分离,839个标记在父本或母本中出现并在子代分离,其中母本443(52.8%)个分离标记,父本396(47.2%)个分离标记。卡方检验显示,556个标记符合孟德尔1:1分离。筛选微卫星标记中30个在家系中具有作图信息,其中19个可用于母本作图,19个可用于父本作图。 利用Mapmaker 3.0/EXP软件对分离标记进行连锁分析。358个分子标记用于雌性遗传连锁分析,其中包括19个微卫星标记,199个AFLP标记和11个微卫星标记定位在雌性框架图谱中。雌性框架图谱共有25个连锁群,总长度为3148.3 cM。标记之间最大间隔为37.5 cM,平均间隔为17.0 cM,连锁群的分子标记数最大为21个最小为4个。用于雄性连锁分析的分子标记共有332个,其中包含19个微卫星标记。207个标记定位于23个连锁群上,其中AFLP标记数为196个,微卫星标记数为11个。23个连锁群总长度为3059.8 cM,标记间最大间隔38.6 cM,平均间隔16.6 cM。每个连锁群的长度范围在40 cM到271.4 cM之间,标记数在18到4个之间,包括二、三连体在内的雄性连锁图谱共覆盖3227 cM。雌雄基因组的预测长度分别为4053.7 cM和3816.3 cM,因此,所构建的雌雄连锁图谱覆盖率分别为84.0%和84.5%。通过共有微卫星标记,有3个连锁群在两个图谱中对应。分子标记在两个图谱中呈均匀分布,没有成簇现象。 分子标记筛选、遗传图谱的构建为刺参分子标记辅助选择育种,经济性状QTL定位和比较基因作图打下基础,并且最终将促进中国刺参遗传改良和新品种的培育工作。 第二部分 卵母细胞成熟过程研究 对刺参卵母细胞的体外诱导成熟方法进行探索,并且通过透射电子显微镜、扫描电子显微镜和激光共聚焦显微镜结合超薄切片技术及间接免疫荧光染色技术研究卵母细胞成熟的生物学过程。 分别利用在海参中有诱导作用的海星神经提取液和二硫苏糖醇(DTT)对从成熟卵巢解剖出的刺参卵母细胞进行诱导成熟试验,结果显示,刺参的卵母细胞在海水中不会发生自发成熟,海星神经提取液以及神经提取液加滤泡悬浮液对卵母细胞没有诱导成熟的作用,而二硫苏糖醇处理可以诱导卵母细胞生发泡破裂,当DTT溶液的浓度处于10-1 mol/L到10-3 mol/L之间时,对刺参卵母细胞的促熟作用较为明显,在10-2 mol/L左右时,卵母细胞的诱导成熟率可以达到90%以上。未成熟的卵母细胞处于第一次减数分裂前期,不具备受精能力。经DTT诱导后,生发泡发生移动并破裂,染色体排列到赤道板上,然后第一、二极体先后排出,诱导成熟的卵母细胞排出极体的时间与自然受精的卵子一致。在卵母细胞成熟过程中有受精膜举起的现象,说明精子入卵不是受精膜举起的必要条件。卵母细胞只有在生发泡破裂之后才具有受精能力,从生发泡破裂到第二极体排出前的整个减数分裂过程中,卵母细胞都可以受精,但是只有在第一极体排出前受精的卵母细胞才能发生卵裂。人工促熟的卵母细胞受精后,形成的胚胎似乎并不能正常发育,试验过程中最多只得到了8细胞期的胚胎,之后细胞便产生畸形并停止分裂,最终裂解消失。 利用DTT诱导刺参卵母细胞成熟,综合运用光镜、电子显微镜及激光共聚焦技术观察卵母细胞成熟过程,分析了卵母细胞表面动物极突起在卵母细胞脱滤泡中的作用,以及卵母细胞动物极突起和微管组织在生发泡移动过程中所起的作用。卵母细胞通过动物极突起连接到滤泡上,在脱滤泡作用开始时,卵母细胞动物极突起刺入并穿过滤泡膜,使得滤泡膜表面形成一个缺口,然后整个卵母细胞开始从缺口处挤出。脱滤泡的作用力来源有两种:胶膜层的水合作用以及滤泡的收缩。通过激光共聚焦显微镜观察,未成熟的卵母细胞中存在5种类型的微管,并且有两个微管组织中心锚定在卵母细胞突起下方。减数分裂重新启动时,生发泡沿微管向动物极移动,至细胞膜下时破裂。微管解聚对照实验证明驱动生发泡移动的细胞结构为微管束。生发泡破裂后,两个微管组织中心组织形成减数分裂纺锤体,然后第一极体以“收缩-排出”的独特方式排出。 本研究填补了刺参繁殖生物学研究中的缺失环节,为刺参人工繁育技术提供理论基础和指导。

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The locations and effects of quantitative trait loci (QTL) were estimated for nine characters for growth-related traits in the Pacific abalone (Haliotis discus hannai Ino) using a randomly amplified polymorphic DNA (RAPD), amplification fragment length polymorphism (AFLP) and SSR genetic linkage map. Twenty-eight putatively significant QTLs (LOD > 2.4) were detected for nine traits (shell length, shell width, total weight, shell weight, weight of soft part, muscle weight, gonad and digestive gland weight, mantle weight and gill weight). The percentage of phenotypic variation explained by a single QTL ranged from 8.0% to 35.9%. The significant correlations (P < 0.001) were found among all the growth-related traits, and Pearson's correlation coefficients were more than 0.81. For the female map, the QTL for growth were concentrated on groups 1 and 4 linkage maps. On the male map, the QTL that influenced growth-related traits gathered on the groups 1 and 9 linkage maps. Genetic linkage map construction and QTL analysis for growth-related traits are the basis for the marker-assisted selection and will eventually improve production and quality of the Pacific abalone.

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Chromosome identification is an essential step in genomic research, which so far has not been possible in oysters. We tested bacteriophage P1 clones for chromosomal identification in the eastern oyster Crassostrea virginica, using fluorescence in situ hybridization (FISH). P1 clones were labeled with digoxigenin-11-dUTP using nick translation. Hybridization was detected with fluorescein-isothiocyanate-labeled anti-digoxigenin antibodies and amplified with 2 layers of antibodies. Nine of the 21 P1 clones tested produced clear and consistent FISH signals when Cot-1 DNA was used as a blocking agent against repetitive sequences. Karyotypic analysis and cohybridization positively assigned the 9 P1 clones to 7 chromosomes. The remaining 3 chromosomes can be separated by size and arm ratio. Five of the 9 P1 clones were sequenced at both ends, providing sequence-tagged sites that can be used to integrate linkage and cytogenetic maps. One sequence is part of the bone morphogenetic protein type 1b receptor, a member of the transforming growth factor superfamily, and mapped to the telomeric region of the long arm of chromosome 2. This study shows that large-insert clones such as P1 are useful as chromosome-specific FISH probes and for gene mapping in oysters.

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We constructed genetic linkage maps for the bay scallop Argopecten irradians using AFLP and microsatellite markers and conducted composite interval mapping (CIM) of body-size-related traits. Three hundred seventeen AFLP and 10 microsatellite markers were used for map construction. The female parent map contained 120 markers in 15 linkage groups, spanning 479.6 cM with an average interval of 7.0 cM. The male parent map had 190 markers in 17 linkage groups, covering 883.8 cM at 7.2 cM per marker. The observed coverage was 70.4% for the female and 81.1% for the male map. Markers that were distorted toward the same direction were closely linked to each other on the genetic maps, suggesting the presence of genes important for survival. Six size-related traits, shell length, shell height, shell width, total weight, soft tissue weight, and shell weight, were measured for QTL mapping. The size data were significantly correlated with each other. We subjected the data, log transformed firstly, to a principle component analysis and use the first principle component for QTL mapping. CIM analysis revealed one significant QTL (LOD=2.69, 1000 permutation, P<0.05) in linkage group 3 on the female parent map. The mapping of size-related QTL in this study raises the possibility of improving the growth of bay scallops through marker-assisted selection. (c) 2007 Published by Elsevier B.V.

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Amplified fragment length polymorphisms (AFLP) were used to study the inheritance of shell color in Argopecten irradians. Two scallops, one with orange and the other with white shells, were used as parents to produce four F-1 families by selfing and outcrossing. Eighty-eight progeny, 37 orange and 51 white, were randomly selected from one of the families for segregation and mapping analysis with AFLP and microsatellite markers. Twenty-five AFLP primer pairs were screened, yielding 1138 fragments, among which 148 (13.0%) were polymorphic in two parents and segregated in progeny. Six AFLP markers showed significant (P < 0.05) association with shell color. All six loci were mapped to one linkage group. One of the markers, F1f335, is completely linked to the gene for orange shell, which we designated as Orange1, without any recombination in the progeny we sampled. The marker was amplified in the orange parent and all orange progeny, but absent in the white parent and all the white progeny. The close linkage between F1f335 and Orange1 was validated using bulk segregation analysis in two natural populations, and all our data indicate that F1f335 is specific for the shell color gene, Orange1. The genomic mapping of a shell color gene in bay scallop improves our understanding of shell color inheritance and may contribute to the breeding of molluscs with desired shell colors.

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提出一种新型链式可重构模块机器人平台,该机器人平台具有手动可重构和自动变形的特点,介绍一种三模块变形机器人样机。组成机器人的单个模块可以简化为由模块本体、连接臂和偏置关节组成。模块的数量可以根据实际工作的需要进行选择,模块间的连接具有规则连接和非规则连接两种方式;同时,由连接模块的偏置关节的运动,模块间的相对位置可以改变。由于模块连接方式的不同和模块间相对位置的变化,变形机器人具有多种非同构构形;为此,根据模块的物理结构和邻接关系提出了用构形矩阵来表达机器人结构的拓扑信息,并在仿真环境下进行等效描述;提出基于组合计数原理的递归算法,用于多模块变形机器人的非同构构形的计数,并根据构形矩阵的拓扑信息对构形进行评价。最后根据仿真结果给出了一种三模块变形机器人样机对称构形的设计示例,验证了算法的可行性。

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针对五轴数控机床平面约束机构进行了误差分析 ,指出了并联机床平面约束机构误差主要影响因素为机构的制造误差和安装误差·前者与由其引起的约束机构顶边中点沿x方向的位移成非线性关系 ,而后者则成线性关系·提出了一种依据测量数据反演非线性误差模型的建模方法 ,给出了五轴并联机床约束机构实测信息与模型输出间的多项式误差模型·比较仿真结果与测量结果可知 ,基于上述方法建立的误差模型精确 ,进而利用该模型对机床进行实时精度补偿 ,可使机床x方向定位精度大为提高

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介绍了OPC服务器中用于与硬件设备I/O交互的动态链接库的开发方法,并着重讨论了数据类型转换问题。

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以钢坯修磨为实用目的研制的一台机器人化三腿机床,具有刚度大、负载能力强、机构简单、工作空间大、无运动耦合及奇异位形等优点,首次解决了钢坯局部修磨自动化问题,配以其它加工执行器还可实现多种工艺要求。建立了该机床的运动学逆、正解方程,对其工作空间和受力分析进行了介绍,并介绍了局部修磨自动化控制系统

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本文阐述了大型工业企业综合自动化系统体系结构中经营管理层的对象模型(资金流模型)。首先论述了该模型在自动化体系结构中的地位和作用,然后分析了企业生产经营过程中发生的资金流,提出用借贷流程图方法表达资金流模型,并将这一方法与国际通用的借贷记帐法相联系,从而揭示了资金流模型与会计核算的内在联系.本文还对企业生产与经营活动的几个主要过程用借贷流程图进行了细化描述。

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介绍一种新型激光叠焊系统,利用该系统可将尺寸范围为12.0m×1.5m厚度不等的两块不锈钢板重叠焊接在一起。针对大尺寸不锈钢板尺寸大、易变形等特点提出了主—辅式压紧机构,有效地控制了焊接过程中大尺寸板材的变形并消除了板材间隙;设计了ufxyz型四轴联动方案:u轴与x轴同向,u轴驱动钢板进行大范围运动,x轴驱动激光头小范围运动。u轴与x轴的复合运动提高系统精度的同时提高了系统焊接动态响应速度。对实际焊接板材进行试验验证,结果表明使用该系统进行焊接的钢板可承受压强最大能达到6.1MPa。

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The loess-paleosol sequences in China are among the best continental records of paleoclimate changes. Although numerous sedimentological and geochemical studies have contributed greatly to the understanding of past climate changes during this period, it is still necessary to decipher more details through investigating these sequences using various approaches including biological analyses. In this study, we analyze the mollusk fossil assemblages preserved in the upper part of the Xifeng section, from the fifth loess layer (L5) to the Holocene soil (S0), with the sampling interval of 10 cm. The main results and conclusions obtained are as follows: 1. A continuous terrestrial mollusk fossil record, covering the past 500 ka, has been obtained from the Xifeng loess-paleosol sequence, which provides important biological data for the study of paleoenvironmental changes in the Loess Plateau and its comparison with marine record during this period. A total of 475 mollusk assemblages were studied, and twenty-one species have been identified among the 210,000 mollusk individuals counted. Among these species, most have modern representatives and are found in previous terrestrial mollusk studies of Chinese loess-paleosol sequences. Thus, they can be grouped into cold-aridiphilous, thermo-humidiphilous, oriental, and cool-humidiphilous ecological groups, as defined by previous studies. 2. Comparison of mollusk assemblages between the last five glacials and four interglacials and Holocene shows very different climate conditions. The warmest period occurred at MIS 11, MIS 5e, and Holocene, respectively. The coldest period is the Last Glacial Maximam, rather than the MIS 12. 3. Our mollusk record provides insight into the climate conditions in the Loess Plateau during the MIS 11, interpreted as the closest analog to the present interglacial. S4 paleosol, equivalent of MIS 11, developed under two major different climate regimes: ranging from the very warm–humid early phase to the mild-cool late interval. Furthermore, a cooling spell has been documented at the interglacial optimum, reflecting unstable climate conditions. The early warm–humid conditions lasted over 30 ka, supporting that MIS 11 is a unique long interglacial in the Quaternary climate history. 4. Comparison of MIS 11 and Holocene climates based on the mollusk species compositions indicates major differences. The climate at the early part of MIS 11 was warmer and more humid than during the Holocene optimum period, but the conditions during the late part of MIS 11 were similar to or cooler than late Holocene. Our study indicates that the extent of warming during the Holocene might be significantly less than the conditions that prevailed during the early part of MIS 11 interglacial period. 5. Two strong summer monsoon events were observed during the MIS 12 and MIS 10. They correspond to the maximam values of insolation gradient between low and high latitudes, suggesting a causal linkage. 6. Our study, combined with the previously investigated Luochuan land snail record, reveals that the climate in the Loess Plateau during MIS 3 experienced three stages: relatively warm, humid climate prevailed during MIS 3c, relatively cold, dry climate during MIS 3b, and relatively warm-humid period during MIS 3a. Climate at this time fluctuated frequently in Luochuan, and changed from warm-cool to cold-dry in Xifeng. Our results reveal that the relatively warm-humid climate during MIS 3c may be resulted from an increasing insolation gradient controlled by obliquity. Our result also reveals that obvious regional difference existed in the Loess Plateau during MIS 3. A greater climate gradient occurred during this time compared with today’s climate pattern in the Loess Plateau.

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The research area of this paper covers the maximum exploration projects of CNPC, including Blocks 1/2/4 and Block 6 of the Muglad basin and the Melut basin in Bocks 3/7 in Sudan. Based on the study of the evolution history of the Central African Shear Zone (CASZ), structural styles and filling characteristics of the rift basins, it is put forward that the rift basins in Sudan are typical passive rift basins undergoing the strike-slip, extension, compression and inversion since the Cretaceous. The three-stage rift basins overlapped obliquely. The extension and rifting during the Early Cretaceous is 50-70% of the total extension. The features of the passive rift basins decided that there is a single sedimentary cycle and one set of active source rocks within the middle. Influenced by the three-stage rifting and low thermal gradient, hydrocarbon generation and charging took place very late, and the oil pool formation mechanism is very unique from the Lower Cretaceous rift sequences to the Paleogene. The reservoir-seal assemblages are very complicated in time and space. The sealing capacity of cap rocks was controlled by the CASZ. In general the oils become heavier towards the CASZ and lighter far away. The oil biodegradation is the reason causing the high total acid number. The determination of effective reservoir depth ensures that all discovered fields up to now are high-production fields. The propagation and growth of boundary faults in the rift basins can be divided into a simple fault propagation pattern and a fault growth-linkage pattern. It is firstly found that the linkage of boundary fault segments controls the formation of petroleum systems. Three methods have been established to outline petroleum systems. And a new classification scheme of rift-type petroleum system has been put forward: pre-rift, syn-rift (including passive and active) and post-rift petroleum systems. This scheme will be very important for the further exploration of rift basins. This paper firstly established the formation models of oil pools for the passive rift basins in Sudan: the coupling of accommodation zones and main plays for the formation of giant fields. The overlapping of late rifting broke the anticlines to be several fault-blocks. This process determined that anti-fault blocks are the main traptypes in the cretaceous sequences and anticlines in the Paleogene. This can explain why the traptypes are different between the Muglad and Mefut basins, and will provide theoretic guidance for the exploration strategy. The established formation mechanism and models in this paper have had great potential guidance and promotion for the exploration in Sudan, and resulted in significant economic and social benefit. A giant field of 500 million tons oil in place was found 2003. The cost in Blocks 3/7 is only 0.25

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Homogeneous DNA hybridization assay based on the luminescence resonance energy transfer (LRET) from a new luminescence terbium chelate, N,N,N-1,N-1-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-phenylpyridine]tetrakis(acetic acid) (BPTA)-Tb3+ (lambda(ex) = 325 nm and lambda(em) = 545 nm) to an organic dye, Cy3 (A,. = 548 nm and A,. = 565 nm), has been developed. In the system, two DNA probes whose sequences are complementary to the two different consecutive sequences of a target DNA are used; one of the probes is labeled with the Tb3+ chelate at the T-end, and the other is with Cy3 at the 5'-end. Labeling of the Tb3+ chelate is accomplished via the linkage of a biotin-labeled DNA probe with the Tb3+ chelate-labeled streptavidin. Strong sensitized emission of Cy3 was observed upon excitation of the Tb3+ chelate at 325 run, when the two probe DNAs were hybridized with the target DNA. The sensitivity of the assay was very high compared with those of the previous homogeneous-format assays using the conventional organic dyes; the detection limit of the present assay is about 30 pM of the target DNA strand.

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Yang, Y., Humphreys, P., & McIvor, R. (2006). Business service quality in an e-commerce environment. Supply Chain Management: An International Journal, 11 (3), 195-201. RAE2008