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1.
We investigated genetic variation within and between 3 populations of Gaura neomexicana ssp. coloradensis , a federally listed threatened species, using inter-simple sequence repeats. The data matrix included 24 individuals scored for 88 bands, with 3.4% missing data. Cluster analysis showed that members of the 3 populations are very similar and are intermixed in the phenogram. Principal coordinate analysis indicated that members of the Crow Creek population are different from the Diamond Creek and ""unnamed drainage"" populations. This could be the result of historic differences, current changes in vegetation at the Crow Creek site, or an artifact of limited sampling. In any case, for management purposes it is best to preserve the dwindling population at Crow Creek as well as the thriving populations at the other 2 sites. 相似文献
2.
Dorothy E. Beetle 《西北部美国博物学家》2011,49(4)
Wyoming lacks a rich molluscan fauna due to its considerable elevation, extremes of temperature, the short period between killing frosts, scanty, moisture, and intermittent creeks. Recent mollusks found in the state total 42 genera (109 species), including 6 genera (23 species) of bivalves, 15 genera (42 species) of freshwater gastropods, and 21 genera (44 species) of land gastropods. Synonymy, the counties in which each species was collected, and habitat notes are given. 相似文献
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Dorothy Chase W. C. Ullrick K. A. Dasse D. J. Burke A. H. Goldberg 《Cellular and molecular life sciences : CMLS》1981,37(12):1300-1301
Summary Results of unilateral achilles tenotomy on older (350–410 g) male rats, showed that the general width of Z-lines in the tenotomized muscles was not significantly altered by this procedure. Streaming of the Z-lines and rod formations was still present, as in younger rats.This investigation was supported in part by NIH grants 1-RO1-NS-14033 and 1-T32-07224. 相似文献
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Mariathasan S Newton K Monack DM Vucic D French DM Lee WP Roose-Girma M Erickson S Dixit VM 《Nature》2004,430(6996):213-218
Specific adaptors regulate the activation of initiator caspases; for example, FADD and Apaf-1 engage caspases 8 and 9, respectively. The adaptors ASC, Ipaf and RIP2 have each been proposed to regulate caspase-1 (also called interleukin (IL)-1 converting enzyme), which is activated within the 'inflammasome', a complex comprising several adaptors. Here we show the impact of ASC-, Ipaf- or RIP2-deficiency on inflammasome function. ASC was essential for extracellular ATP-driven activation of caspase-1 in toll-like receptor (TLR)-stimulated macrophages. Accordingly, ASC-deficient macrophages exhibited defective maturation of IL-1beta and IL-18, and ASC-null mice were resistant to lipopolysaccharide-induced endotoxic shock. Furthermore, activation of caspase-1 in response to an intracellular pathogen (Salmonella typhimurium) was abrogated severely in ASC-null macrophages. Unexpectedly, Ipaf-deficient macrophages activated caspase-1 in response to TLR plus ATP stimulation but not S. typhimurium. Caspase-1 activation was not compromised by loss of RIP2. These data show that whereas ASC is key to caspase-1 activation within the inflammasome, Ipaf provides a special conduit to the inflammasome for signals triggered by intracellular pathogens. Notably, cell death triggered by stimuli that engage caspase-1 was ablated in macrophages lacking either ASC or Ipaf, suggesting a coupling between the inflammatory and cell death pathways. 相似文献
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Spatial scale dictates the productivity-biodiversity relationship 总被引:30,自引:0,他引:30
The diversity of life is heterogeneously distributed across the Earth. A primary cause for this pattern is the heterogeneity in the amount of energy, or primary productivity (the rate of carbon fixed through photosynthesis), available to the biota in a given location. But the shape of the relationship between productivity and species diversity is highly variable. In many cases, the relationship is 'hump-shaped', where diversity peaks at intermediate productivity. In other cases, diversity increases linearly with productivity. A possible reason for this discrepancy is that data are often collected at different spatial scales. If the mechanisms that determine species diversity vary with spatial scale, then so would the shape of the productivity-diversity relationship. Here, we present evidence for scale-dependent productivity-diversity patterns in ponds. When the data were viewed at a local scale (among ponds), the relationship was hump-shaped, whereas when the same data were viewed at a regional scale (among watersheds), the relationship was positively linear. This dependence on scale results because dissimilarity in local species composition within regions increased with productivity. 相似文献
9.
Floyd JA Gold DA Concepcion D Poon TH Wang X Keithley E Chen D Ward EJ Chinn SB Friedman RA Yu HT Moriwaki K Shiroishi T Hamilton BA 《Nature genetics》2003,35(3):221-228
Endogenous retroviruses have shaped the evolution of mammalian genomes. Host genes that control the effects of retrovirus insertions are therefore of great interest. The modifier-of-vibrator-1 locus (Mvb1) controls levels of correctly processed mRNA from genes mutated by endogenous retrovirus insertions into introns, including the Pitpn(vb) tremor mutation and the Eya1(BOR) model of human branchiootorenal syndrome. Positional complementation cloning identifies Mvb1 as the nuclear export factor Nxf1, providing an unexpected link between the mRNA export receptor and pre-mRNA processing. Population structure of the suppressive allele in wild Mus musculus castaneus suggests selective advantage. A congenic Mvb1(CAST) allele is a useful tool for modifying gene expression from existing mutations and could be used to manipulate engineered mutations containing retroviral elements. 相似文献
10.
S. G. Sullivan Dorothy A. Potter Marjorie R. Krauss J. Dancis R. P. Cox 《Cellular and molecular life sciences : CMLS》1979,35(8):1043-1044
Summary Valine decarboxylation was significantly increased and leucine decarboxylation was significantly decreased in rat liver slices following hypophysectomy. In both normal and hypophysectomized rats decarboxylation of leucine exceeded that of valine in slices whereas the reverse was observed with the respective keto acids and mitochondria.Acknowledgments. This study was supported by the National Institutes of Health and the Samuel A. Berger Foundation. 相似文献