101 resultados para arm


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Zhikong scallop Chlamys farreri(Jones et Preston) is an economically important species in China. Understanding its immune system would be of great help in controlling diseases. In the present study, an important immunity-related gene, the Lipopolysaccharide and Beta-1,3-glucan Binding Protein (LGBP) gene, was located on C. farreri chromosomes by mapping several lgbp-containing BAC clones through fluorescence in situ hybridization (FISH). Through the localization of various BAC clones, it was shown that only one locus of this gene existed in the genome of C. farreri, and that this was located on the long arm of a pair of homologous chromosomes. Molecular markers, consisting of eight single nucleotide polymorphism (SNPs) markers and one insertion-deletion (indel), were developed from the LGBP gene. Indel marker testing in an F1 family revealed slightly distorted segregation (p = 0.0472). These markers can be used to map the LGBP gene to the linkage map and assign the linkage group to the corresponding chromosome. Segregation distortion of the indel marker indicated genes with deleterious alleles might exist in the surrounding region of the LGBP gene.

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The proton-translocating NADH:ubiquinone oxidoreductase (complex I) has been purified from Aquifex aeolicus, a hyperthermophilic eubacterium of known genome sequence. The purified detergent solubilized enzyme is highly active above 50 degreesC. The specific activity for electron transfer from NADH to decylubiquinone is 29 U/mg at 80 degreesC. The A. aeolicus complex I is completely sensitive to rotenone and 2-n-decyl-quinazoline-4-yl-amine. SDS polyacrylamide gel electrophoresis shows that it may contain up to 14 subunits. N-terminal amino acid sequencing of the bands indicates the presence of a stable subcomplex, which is composed of subunits E, F, and G. The isolated complex is highly stable and active in a temperature range from 50 to 90 degreesC, with a half-life of about 10 h at 80 degreesC. The activity shows a linear Arrhenius plot at 50-85 degreesC with an activation energy at 31.92 J/mol K. Single particle electron microscopy shows that the A. aeolicus complex I has the typical L-shape. However, visual inspection of averaged images reveals many more details in the external arm of the complex than has been observed for complex I from other sources. In addition, the angle (90degrees) between the cytoplasmic peripheral arm and the membrane intrinsic arm of the complex appears to be invariant.

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Twenty microsatellite markers (Po1, Po13, Po33, Po35, Po42, Po48, Po56, Po89, Po91, kop6, kop7, kop8, kop12, kop15, kop18, kop21, kop22, kop23, kop26, Po-strl) were used to assess the meiogynogenetic and mitogynogenetic stocks of the left-eyed flounder, Paralichthys olivaceus, which were derived from single pair crossing. Twelve of the 20 loci utilized showed heterozygosity in the female and were mapped in relation to their centromeres in the meiogynogenetic diploid flounder. Microsatellite-centromere map distance, calculated under the assumption of complete interference, ranged from 15.8 cM for kop22 to 50 cM for Po13, Po56 and Po89. Excluding the kop22, the heterozygosities of the rest of the loci were close to 100%, suggesting the occurrence of near complete interference on the chromosome arms that carried these loci. In the mitogynogenetic diploid flounder, each individual showed exact homozygousity and the segregation profiles did not deviate from the Mendelian 1: 1 pattern. The results indicated that there was no lethal gene linked with the loci analyzed. Such high interference accounted for the high recombination rates and large map distances. The Po13 and Po56 loci, Po91 and kop18 loci, kop15 and kop21 loci are tightly linked on the same chromosome arm in pairs.

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Our rock magnetic analysis of core Ph05 from the West Philippine Sea demonstrates that the core preserves a strong, stable remanent magnetization and meets the magnetic mineral criteria for relative paleointensity (RPI) analyses. The magnetic minerals in the sequence are dominated by pseudosingle-domain magnetite, and the concentration of magnetic minerals is at the same scale. Both the conventional normalizing method and the pseudo-Thellier method were used in conjunction with the examination of the rock magnetic properties and natural remanent magnetization. Susceptibility (chi), anhysteretic remnant magnetization (ARM) and saturation isothermal remnant magnetization (SIRM) were used as the natural remanent magnetization normalizer. However, coherence analysis indicated that only ARM is more suitable for paleointensity reconstruction. The age model of core is established based on oxygen isotope data and AMS(14)C data, which is consistent with the age model estimated from RPI records. The relative paleointensity data provide a continuous record of the intensity variation during the last 200 ka, which correlates well with the global references RPI stacks. Several prominent low paleointensity values are identified and are correlated to the main RPI minima in the SINT-200 record, suggesting that the sediments have recorded the real changes of geomagnetic field.

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本论文的主要实验测量工作可分为古地磁学与地球化学二大部分。在古地磁学方面。对JX91-2A(168),JX91-2B(80),JX91-3A(66)和JX91-3B(137)共451个样品进行了天然剩磁(NRM)及交变退磁测量,还进行了磁化率及磁化率各向异性的测量。对JX91-2A,JX91-2B和JX91-3A开展了岩石磁学研究,测量了非粘滞性剩磁(ARM),等温剩磁(ARM),饱和等温剩磁(FIRM)以及个别样品的FIRM衰减曲线,对JX91-3B求出了中间破坏强度(MDF)。在地球化学方面,对JX91-2A(79),JX91-3B(67),JX91-3m(50)和JX91-4G(27)共223个样品进行了X光萤光(XRF)分析。包括10种主要元素及21种向量元素,以及X光衍射(XRD)分析。还对JX91-2A进行了有机碳、微体古生物学及稳定碳氧同位素分析;对JX-91-3B进行了~(210)Pb 测量。另外还对此四岩芯测定了含水量及粒度分布等。所有实验数据都用计算机进行了分析处理,并做了广泛的多学科综合对比研究。在充分借鉴前人成果的基础上,本论文就以下四个方面的问题得到了一点新的认识。一、渤海黄河口外的浊流系统及浅水浊流沉积。这一浊流系统的存在具有多方面的证据。二、渤海沉积物的高精度年代学。对于渤海中央盆地沉积物主要采用了全新世以来的海平面变化曲线及古地磁场强度曲线确定年代,定出JX91-2A底部年代为距今8,500年。三、古地磁记录改正方法及渤海地区古地磁长期变样本曲线的建立。四、渤海古环境综合分析及黄河全新世以来的河道变迁。

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沉积物可以提供连续的地磁场相对强度(RPI)记录,这些记录在全球范围内的对比具有一致性。目前RPI记录越来越多地在布容极性期内作为千年尺度高精度的地层对比手段,但由于构建RPI所需的岩石磁学标准较高,总体来说,RPI数据还相对缺乏,尤其是太平洋地区连续的RPI记录更是相对较少。本文以西太平洋特定海域沉积物为研究对象,进行了古地磁和岩石磁学方面等多个参数的综合测量,通过归一化天然剩磁得到了地磁场相对强度变化曲线,为RPI研究提供了新的记录,为研究区测年提供了新的手段。 西菲律宾海的Ph05孔沉积物的岩石磁学和古地磁研究表明,岩芯中的载磁矿物比较单一,以低矫顽力的磁铁矿为主,χ、ARM及SIRM等参数指示的磁性矿物的含量变化不大。磁性矿物的颗粒以准单畴为主,粒度指示参数χARM/χ具有冰期-间冰期旋回变化。通过交变退磁可得到稳定的特征剩磁,32-38 cm及108-110 cm处发现负倾角,并伴随着RPI的低值。谱分析检验后选择ARM作为归一化参数,通过ARM归一化天然剩磁获得了200 ka以来的地磁场相对强度记录。重建的RPI记录与综合曲线Sint-200有良好对比,可以反映全球性的信号。基于RPI建立的年代模型与氧碳同位素年代模型相似,可以作为独立的定年手段。 对东菲律宾海帕里西维拉海盆西侧F090102孔柱样沉积物进行了系统的古地磁和岩石磁学分析,结果表明样品适合进行相对强度研究。根据功率谱分析结果,选择非磁滞剩磁作为归一化的参数,得到约2 Ma以来的地球磁场相对强度变化曲线。该曲线与SINT-2000曲线可详细对比,比如呈比较典型的锯齿状特征,布容期内的记录与800 ka以来的SINT-800曲线相符。布容/松山极性转换期呈单强度降低的特征,在极性转换期和极性漂移期,相对强度曲线表现为显著低值。 对东海内陆架泥质区沉积物EC2005孔的磁学研究表明,岩芯在110 cm即受到还原成岩作用的影响;110-600 cm经历了铁氧化物还原阶段,样品中磁性矿物以PSD磁铁矿为主,随深度增加,其含量快速减少,其间随着硬磁矿物含量的波动,磁学参数也呈现出峰谷变化;600 cm向下岩芯经历硫酸盐还原阶段,各磁学参数都维持在很低的水平,顺磁性颗粒增加,并出现黄铁矿。早期成岩作用及重磁化作用使得古地磁信号被削弱和改造。

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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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Chromosomal location of the 5S ribosomal RNA gene was studied in the eastern oyster, Crassostrea virginica Gmelin. using fluorescence in situ hybridization (FISH). Metaphase chromosomes were obtained from early embryos, and the FISH probe was made by PCR (polymerase chain reaction) amplification of the 5S rRNA gene and labeled by incorporation of digoxigenin-1 1-dUTP during PCR. Hybridization was detected with fluorescein-labeled antidigoxigenin antibodies. Two pairs of FISH signals were observed on metaphase chromosomes. Karyotypic analysis showed that the 5S rRNA gene cluster is interstitially located on short arms of chromosomes 5 and 6. On chromosome 5, the 5S rRNA genes were located immediately next to the centromere, whereas on chromosome 6, they were located approximately half way between the telomere and the centromere. Chromosomes of C. virginica are difficult to identify because of their similarities in size and arm ratio, and the chromosomal location of 5S rRNA genes provides unambiguous identification of chromosomes 5 and 6. Previous studies have mapped the major rRNA gene cluster (18S-5.8S-28S) to chromosome 2. and this study shows that the 5S rRNA gene cluster is not linked to the major rRNA genes and duplicated during evolution.

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Karyotype and chromosomal location of the major ribosomal RNA genes were studied in the hard clam (Mercenaria mercenaria Linnaeus) using fluorescence in situ hybridization (FISH). Metaphase chromosomes were obtained from early embryos. Internal transcribed spacers (ITS) between major RNA genes were amplified and used as FISH probes. The probes were labeled with digoxigenin-11-dUTP by polymerase chain reaction and detected with fluorescein-labeled anti-digoxigenin antibodies. FISH with the ITS probes produced two to four signals per nucleus or metaphase. M. mercenaria had a haploid number of 19 chromosomes with a karyotype of seven metacentric, four metacentric or submetacentric, seven submetacentric, and one submetacentric or subtelocentric chromosomes (7M + 4M/SM + 7SM + 1SM/ST). Two ITS loci were observed: one located near the centromere on the long arm of Chromosome 10 and the other at the telomere of the short arm of Chromosome 12. FISH signals on Chromosome 10 are strong and consistent, while signals on Chromosome 12 are variable. This study provides the first karyotype and chromosomal assignment of the major RNA genes in M. mercenaria. Similar studies in a wide range of species are needed to understand the role of chromosomal changes in bivalve evolution.

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This paper describes a new species of Metrodoridae, Rhopalotettix taipeieiisis sp. nov. , collected from (lie (arm of Taiwan University in Taipei, Taiwan, and provides a key to the 6 species of the genus Rhopnloteltix Hancock, 1910. Type specimens are deposited in the Department ol Entomology, Taiwan University, Taipei, Taiwan.

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The rye B chromosome is a supernumerary chromosome that increases in number in its host by directed postmeiotic drive. Two types of rye B chromosomes that had been introduced into common wheat were dissected into separate segments by the gametocidal system to produce a number of rearranged B chromosomes, such as telosomes, terminal deletions and translocations with wheat chromosomes. A total of 13 dissected B chromosomes were isolated in common wheat, and were investigated for their nondisjunction. properties. Rearranged B chromosomes, separated from their B-specific repetitive sequences on the distal part of the long arm, did not undergo nondisjunction, and neither did a translocated wheat chromosome carrying a long-arm distal segment containing the B-specific repetitive sequences. However, such rearranged B chromosomes, missing their B-specific sequences could undergo nondisjunction when they coexisted with the standard B chromosome or a wheat chromosome carrying the B-specific sequences. Deficiencies of the short arm did not completely abolish the nondisjunction properties of the B chromosome, but did reduce the frequency of nondisjunction. These results confirmed previous suggestions that the directed nondisjunction of the rye B chromosome is controlled by two elements, pericentromeric sticking sites and a trans-acting element carried at the distal region of the long arm of the B chromosome. Additionally, it is now shown that the distal region of the long arm of the B chromosome which provides this function is that which carries the B-specific repetitive sequences.

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本文设计了研磨抛光机器人运动控制器的核心硬件结构和软件模块,采用了参数模糊自整定PID机器人关节位置控制策略,通过实验表明该运动控制器可以大大降低研磨抛光机器人的位置跟踪误差。建立的模块化的软件体系,便于运动控制器的维护和扩展,并可将其应用到其它工业机器人上。

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研发了基于CAN总线的新型机器人示教盒系统,采用ARM芯片为核心,并在其上运行了实时操作系统μC/OS-II。设计了一套CAN网络通讯协议,实现了一个示教盒同时示教多台机器人的一对多示教模式,在很大程度上改进和提高了机器人示教盒的性能。

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分析超高压输电线路架空地线上的障碍物类型以及跨越这些障碍的过程。可以发现,巡检机器人采用双臂交替跨越障碍,越障过程简单。但是由于受巡检机器人自身重力偏矩的影响和手臂长度尺寸的限制,当单臂悬架在架空地线上时,导致巡检机器人本体倾斜,另一手臂完成脱线和上线任务变得十分困难,有时甚至造成越障失败。为了解决上述问题,提出质量调节的控制方法。该方法通过调节巡检机器人的质心,使巡检机器人的本体保持水平状态。为了验证质量调节控制方法的正确性,采用Lagrange方法建立巡检机器人动力学模型,通过仿真试验、实验室模拟实际架空地线试验以及超高压实际现场试验说明了提出方法的可行性。

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设计了一种基于机器视觉导航和杂草识别的除草机器人模型,该机器人能沿作物行间自主行走并能准确地识别和"清除"杂草。设计了除草机器人的机械臂除草执行系统,求取了机械臂运动学逆解,用VC++开发了控制程序。试验显示,图像处理算法所需时间少,能够适应户外自然光线在一定范围的变化,机械臂能够平稳动作并精确定位杂草目标。