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Ian S. Zagon Patricia J. McLaughlin James E. Seely Greg W. Hoeksema Dr. Anthony E. Pegg 《Cell and tissue research》1984,235(2):371-377
Summary Ornithine decarboxylase, a key enzyme in polyamine biosynthesis and cell growth, has been localized in mouse kidney by autoradiography after administration of radiolabeled -difluoromethylornithine. This drug is an enzyme-activated irreversible inhibitor of ornithine decarboxylase and forms a covalent bond with the enzyme. It was found that ornithine decarboxylase is present in all cell types studied but that the highest content occurs in the proximal convoluted tubules followed by the distal convoluted tubules and the collecting tubules. The majority of the enzyme is located in the cytoplasm but about 10–15% is present in the nuclei (often associated with nucleolus-like components) of the cells of the proximal and distal convoluted tubules. The labeled ornithine decarboxylase was lost rapidly from both nucleus and cytoplasm of all the cell types examined, and labeling by radioactive -difluoromethylornithine was greatly reduced if the mice were pretreated for 5 h with cycloheximide to block protein synthesis. These results indicate that ornithine decarboxylase turns over rapidly in all of the cells. 相似文献
3.
The island Koh Tao in the western Gulf of Thailand suffered severe coral bleaching in 2010. Its mushroom coral fauna of 20 species was surveyed during the bleaching in 2010 and after the bleaching in 2011. Multi-species assemblages of free-living mushroom corals occurred around the island, two of which were invaded by corallivorous Drupella snails after the bleaching. Previously these gastropods were known to mainly consume branching corals and hardly any mushroom corals. The snails were found preying on four fungiid species, three of which were susceptible to bleaching. The dietary shift became apparent after populations of preferred prey species (Acroporidae and Pocilloporidae) had died during the bleaching event. It seems that bleaching mortality reduced the availability of preferred prey, causing the corallivores to switch to less preferred species that occur in dense aggregations. 相似文献
4.
Using a battery of seven lectin-ferritin conjugates as probes for cell surface glycoconjugates, we have studied the pattern of plasmalemmal differentiation of cells in the embryonic rat pancreas from day 15 in utero to the early postpartum stage. Our results indicate that differentiation of plasmalemmal glycoconjugates on acinar, endocrine, and centroacinar cells is temporally correlated with development and is unique for each cell type, as indicated by lectin-ferritin binding. Specifically, (a) expression of adult cell surface saccharide phenotype can be detected on presumptive acinar cells as early as 15 d in utero, as indicated by soybean agglutinin binding, and precedes development of intracellular organelles characteristic of mature acinar cells; (b) maturation of the plasmalemma of acinar cells is reached after intracellular cytodifferentiation is completed, as indicated by appearance of Con A and fucoselectin binding sites only at day 19 of development; conversely, maturation of the endocrine cell plasmalemma is accompanied by "loss" (masking) of ricinus communis II agglutinin receptors; and (c) binding sites for fucose lectins and for soybean agglutinin are absent on endocrine and centroacinar cells at all stages examined. We conclude that acinar, centroacinar, and endocrine cells develop from a common progenitor cell(s) whose plasmalemmal carbohydrate composition resembles most closely that of the adult centroacinar cell. Finally, appearance of acinar lumina beginning at approximately 17 d in utero is accompanied by differenetiation of apical and basolateral plasmalemmal domains of epithelial cells, as indicated by enhanced binding of several lectin-ferritin conjugates to the apical plasmalemmal, a pattern that persists from this stage through adult life. 相似文献
5.
Background
Many high-throughput genomic experiments, such as Synthetic Genetic Array and yeast two-hybrid, use colony growth on solid media as a screen metric. These experiments routinely generate over 100,000 data points, making data analysis a time consuming and painstaking process. Here we describe ScreenMill, a new software suite that automates image analysis and simplifies data review and analysis for high-throughput biological experiments. 相似文献6.
Alain Gagnon Matthew S. Miller Stacey A. Hallman Robert Bourbeau D. Ann Herring David JD. Earn Joaquín Madrenas 《PloS one》2013,8(8)
The worldwide spread of a novel influenza A (H1N1) virus in 2009 showed that influenza remains a significant health threat, even for individuals in the prime of life. This paper focuses on the unusually high young adult mortality observed during the Spanish flu pandemic of 1918. Using historical records from Canada and the U.S., we report a peak of mortality at the exact age of 28 during the pandemic and argue that this increased mortality resulted from an early life exposure to influenza during the previous Russian flu pandemic of 1889–90. We posit that in specific instances, development of immunological memory to an influenza virus strain in early life may lead to a dysregulated immune response to antigenically novel strains encountered in later life, thereby increasing the risk of death. Exposure during critical periods of development could also create holes in the T cell repertoire and impair fetal maturation in general, thereby increasing mortality from infectious diseases later in life. Knowledge of the age-pattern of susceptibility to mortality from influenza could improve crisis management during future influenza pandemics.
“The war is over – and I must go” Egon Schiele, 1890–1918.相似文献
7.
Background
Ectomycorrhizal (ECM) fungi provide one of the main pathways for carbon (C) to move from trees into soils, where these fungi make significant contributions to microbial biomass and soil respiration.Scope
ECM fungal species vary significantly in traits that likely influence C sequestration, such that forest C sequestration potential may be driven in part by the existing community composition of ECM fungi. Moreover, accumulating experimental data show that tree genotypes differ in their compatibility with particular ECM fungal species, i.e. mycorrhizal traits of forest trees are heritable. Those traits are genetically correlated with other traits for which tree breeders commonly select, suggesting that selection for traits of interest, such as disease resistance or growth rate, could lead to indirect selection for or against particular mycorrhizal traits of trees in forest plantations.Conclusions
Altogether, these observations suggest that selection of particular tree genotypes could alter the community composition of symbiotic ECM fungi in managed forests, with cascading effects on soil functioning and soil C sequestration. 相似文献8.
9.
Peter JD Andrews Helen Louise Sinclair Claire G Battison Kees H Polderman Giuseppe Citerio Luciana Mascia Bridget A Harris Gordon D Murray Nino Stocchetti David K Menon Haleema Shakur Daniel De Backer 《Trials》2011,12(1):1-13