997 resultados para Kipke, Harry G.


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The Philippine Expedition of 1907-10 was the longest and most extensive assignment of the Albatross's 39-year career. It came about because the United States had acquired the Philippines following the Spanish-American War of 1898 and the bloody Philippine Insurection of 1899-1902. The purpose of the expedition was to surbey and assess the aquatic resources of the Philippine Islands. Dr. Hugh M. Smith, the Deputy Commissioner of the U.S. Bureau of Fisheries, was the Director of the Expedition. Other scientific participants were Frederick M. Chamberlain, Lewis Radcliffe, Paul Bartsch, Harry C. Fasset, Clarence Wells, Albert Burrows, Alvin Seale, and Roy Chapman Andrews. The expedition consisted of a series of cruises, each beginning and ending in Manila and exploring a different part of the island group. In addition to the Philippines proper, the ship also explored parts of the Dutch East Indies and areas around Hong Kong and Taiwan. The expedition returned great quantities of fish and invertebrate speciments as well as hydrographic and fisheries data; most of the material was eventually deposited in the Smithsonian Institution's National Museum of Natural History. The fisehs were formally accessioned into the museum in 1922 and fell under the car of Barton A. Bean, Assistant Curator of Fishes, who then recruited Henry W. Fowler to work up the material. Fowler completed his studies of the entire collection, but only part of it was ever published, due in part to the economic constraints caused by the Depression. The material from the Philippine Expedition constituted the largest single accession of fishes ever received by the museum. These speciments are in good condition today and are still being used in scientific research.

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Harry Hess's hypothesis of sea-floor spreading brought together his long-standing interests in island arcs, oceanic topography, and the oceanic crust. The one unique feature of Hess's hypothesis was the origin of the oceanic crust as a hydration rind on the top of the mantle -- an idea that was not well received, even by the early converts to sea-floor spreading. Hess never changed his mind on this issue, and his stubbornness illuminates the logic of his discovery. Published and archival records show that 1) Hess became convinced the oceanic crust was a hydration rind as early as mid 1958, when he was still a fixist, 2) he devised sea-floor spreading in 1960 to reconcile the hydration-rind model with the newly discovered, high heat flow at oceanic ridge crests, and 3) Hess's new mobilist solution did the least amount of violence to his older fixist solution.

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Interest in development of offshore renewable energy facilities has led to a need for high-quality, statistically robust information on marine wildlife distributions. A practical approach is described to estimate the amount of sampling effort required to have sufficient statistical power to identify species specific “hotspots” and “coldspots” of marine bird abundance and occurrence in an offshore environment divided into discrete spatial units (e.g., lease blocks), where “hotspots” and “coldspots” are defined relative to a reference (e.g., regional) mean abundance and/or occurrence probability for each species of interest. For example, a location with average abundance or occurrence that is three times larger the mean (3x effect size) could be defined as a “hotspot,” and a location that is three times smaller than the mean (1/3x effect size) as a “coldspot.” The choice of the effect size used to define hot and coldspots will generally depend on a combination of ecological and regulatory considerations. A method is also developed for testing the statistical significance of possible hotspots and coldspots. Both methods are illustrated with historical seabird survey data from the USGS Avian Compendium Database.

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  锌指蛋白在植物生长发育中具有重要功能,它们可以识别并结合特定的DNA序列进行转录调控,还能够参与蛋白之间相互作用的调节。我们根据锌指蛋白等转录因子特征结构域的序列特点,从来自10 K水稻芯片的EST数据库中筛选出编码58个EST序列。通过对器官表达特异性的比较分析,从中选出七个只在单一器官表达的基因,并对这七个基因的功能进行研究。对其转基因水稻的表型分析发现,C1基因调节水稻的株高和穗的发育;LIM 家族的F9影响小花的形态,主要体现在雌蕊与雄蕊的发育;锌指蛋白S34调控叶倾角的变化;F14基因编码一个核定位的TFIIIA类锌指蛋白,具体功能尚不清楚;锌指蛋白F35转基因水稻主根缩短,侧根数目显著减少。它编码一个推测的ArfGAP (Arf GTPase activating protein),据此我们将其命名为OsAGAP,并对其进行深入研究。   OsAGAP的cDNA全长为1328bp,编码的蛋白由320个氨基酸组成,含有两个保守结构域:锌指结构域和C2 结构域。其中锌指结构域属于CX2CX16CX2C类,即ArfGAP domain的特征结构。GTP酶活性测定试验表明,OsAGAP蛋白能够激活水稻Arf的GTP酶活性,另外,OsAGAP还能够恢复酵母ArfGAP缺失突变体的表型。说明OsAGAP编码的蛋白是水稻中的一个ArfGAP。   OsAGAP在水稻各器官中均有表达,但强弱有所不同。RNA原位杂交结果显示,它在茎尖分生组织与侧生原基及侧根部位表达强烈;它在根尖主要分布于中央维管组织、分生区、皮层细胞,最有趣的是恰好与生长素在根尖极性运输路径相吻合。在亚细胞水平,OsAGAP广泛分布于细胞膜、细胞质、细胞核。   OsAGAP超表达水稻主根、不定根长度缩短,侧根数目显著减少表现出类似于生长素极性运输突变体的表型。其主根伸长对TIBA的抑制作用不敏感,这暗示OsAGAP超表达水稻的生长素极性运输被破坏;另外,其对各种生长素的作用敏感性也发生变化,对IAA、2,4-D的不敏感,而对NAA的反应与野生型一致,根据各类生长素进出细胞机制不同,可以推测超表达水稻的输入能力存在缺陷。极性运输实验结果表明,超表达水稻极性运输能力被破坏;对生长素输入能力的测定进一步表明,超表达水稻根载体的介导的生长素输入能力显著下降。另外,NAA处理能够恢复超表达水稻中侧根发育受抑的表型缺陷。由此可见,OsAGAP在水稻中超表达破坏了生长素极性运输的输入能力。   FM1-43是一类特异标记囊泡运输的荧光染料。经其染色标记后,OsAGAP超表达水稻细胞内囊泡成片聚集,形成“BFA区间”,表现出囊泡运输被破坏的典型特征。透射电镜观察发现,超表达水稻细胞内有大量的小液泡,其中积累了电子密度很高的颗粒物质。由此推测,可能由于细胞的囊泡运输被破坏,导致胞内的代谢物质不能被正常运送或分泌,而在液泡中暂时贮存以维持细胞环境的稳定。   在酵母和动物细胞中的研究表明, ArfGAP是调控囊泡运输的一个重要因子,然而目前还没有关于ArfGAP在植物细胞中生理作用的报道。我们的结果说明,OsAGAP作为的一个ArfGAP,它通过调控水稻中的囊泡运输,而影响了生长素的极性运输,具体表现在对生长素输入能力的调控。由此,我们推测ArfGAP可能在生长素的极性运输中也起着重要的调控作用。   但OsAGAP在拟南芥中却通过调控植株生长素的水平,而影响了转基因拟南芥根的发育。每种生物都有多个ArfGAP,它们之间的分工存在联系,但各不相同。OsAGAP是拟南芥的外源基因,它在拟南芥中可能以不同于水稻的机制起作用。