The decline in reproductive capacity is one of the first signs of aging and represents a considerable health problem in modern societies such as canada with an increasing maternal age. To prepare for challenges brough...
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The decline in reproductive capacity is one of the first signs of aging and represents a considerable health problem in modern societies such as canada with an increasing maternal age. To prepare for challenges brought up by older maternity, there is a need to understand the biology of reproductive aging at the molecular level. For instance, what are the biochemical signatures associated with aging oocytes that precede and predict the incipient loss in fertilizing ability in these cells? The simple nematode c. elegans has a short reproductive span during which it displays a corresponding drop in oocyte quality overtime thus providing a tractable and relevant model to study germ cell aging. Here, FTIR (Fourier Transform Infrared) microspectroscopy was systematically applied as an imaging platform to address in vivo changes in the macromolecular composition of c. elegans oocytes transitioning from reproductive to post-reproductive stages. Using this pioneering experimental approach optimized to image c. elegans cells, a marked increase in lipid and protein signatures consistent with an altered mobilization of yolk (lipoprotein) was detected in old wild-type oocytes. These results were corroborated using standard fluorescent and transgenic techniques demonstrating a spike in lipoprotein storage in aged oocytes. Finally, a bona fide mutant defective in yolk import served as a proof of method to validate the usefulness and reliability of FTIR microspectroscopy as a mapping tool to quickly and reproducibly draw the biochemical landscape of aging oocytes. Overall, this exploratory study supports a role of lipotoxicity in driving oocyte aging and provides an integrated experimental approach for further studies aimed at dissecting the molecular underpinnings behind reproductive decline in germ cells.
One of the most distinctive colour polymorphisms of any mammal occurs in black bears (Ursus americanus kermodei Hornaday) of the Great Bear Rainforest of coastal British columbia. We use carbon and nitrogen stable iso...
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One of the most distinctive colour polymorphisms of any mammal occurs in black bears (Ursus americanus kermodei Hornaday) of the Great Bear Rainforest of coastal British columbia. We use carbon and nitrogen stable isotope values and c/N ratios along segments of hair shafts obtained from 14 white and 12 black individual bears to quantify dietary niche of the morphs as a test of the multi-niche model for a polymorphism. On Gribbell Island, where the white bear reaches 30%, N-15 is significantly (GLM repeated measures) more enriched (more marine-derived nitrogen) in the white morph than in the black morph in each season (spring, summer, autumn). On the adjacent Princess Royal Island, where the white morph is less common, both morphs are highly enriched during autumn (delta N-15 = +11aEuro degrees), but there are no isotopic differences between morphs in any season. On both islands, c/N ratios (3.1) of the black morph decrease from spring to autumn, converging on the lower average values for the white morph. Our data suggest that niche of the white morph involves increased use of a marine-associated diet and that ecological segregation between the morphs has facilitated the historical persistence of the polymorphism.
在神话传说与现实世界中,并蒂双生的命运成就了无数令人艳羡的两全其美。无论高居奥林匹斯十二主神的同胞姐弟狩猎女神阿尔忒弥斯与太阳神阿波罗,还是实现人类翱翔蓝天梦想的菜特兄弟,亦或16年来横贯网坛的大小威廉姆斯姐妹,都如闪耀的双子星一般造就了一段段佳话。而在赛道上,当全新梅赛德斯-AMG c 63轿跑车于2015年法兰克福车展横空问世后,便与梅赛德斯-AMG c 63轿车组成了叱咤风云的双子战神。两者以无与伦比的惊艳设计、极具爆发力的动力表现以及卓越安全科技,成为当今车坛的传奇双生车型。
为解决遥感相机在运动过程中的抖动造成的图像位置偏移问题,提出了一种实时图像校正算法。由于在FPGA中采用HDL进行算法设计难度大、开发周期长,故设计中采用了c语言进行算法设计,然后借助calypto公司的catapult c Synthesis工具将抽象...
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为解决遥感相机在运动过程中的抖动造成的图像位置偏移问题,提出了一种实时图像校正算法。由于在FPGA中采用HDL进行算法设计难度大、开发周期长,故设计中采用了c语言进行算法设计,然后借助calypto公司的catapult c Synthesis工具将抽象的c设计转换成硬件RTL代码。在catapult c Synthesis中对设计的算法进行了c/c++、RLT协同仿真测试,并在Xilinx Xc5VLX110T型FPGA上进行了验证。仿真测试及硬件验证结果表明,采用catapult c Synthesis设计的算法在时序、性能方面均满足设计要求,能够对偏移的图像进行实时校正。
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