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11.
Samuel Wilks 《BMJ (Clinical research ed.)》1879,1(964):928-930
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Planar cell polarity (PCP) controls the orientation of cells within tissues and the polarized outgrowth of cellular appendages. So far, six PCP core proteins including the transmembrane proteins Frizzled (Fz), Strabismus (Stbm) and Flamingo (Fmi) have been identified. These proteins form asymmetric PCP domains at apical junctions of epithelial cells. Here, we demonstrate that VhaPRR, an accessory subunit of the proton pump V‐ATPase, directly interacts with the protocadherin Fmi through its extracellular domain. It also shows a striking co‐localization with PCP proteins during all pupal wing stages in Drosophila. This localization depends on intact PCP domains. Reversely, VhaPRR is required for stable PCP domains, identifying it as a novel PCP core protein. VhaPRR performs an additional role in vesicular acidification as well as endolysosomal sorting and degradation. Membrane proteins, such as E‐Cadherin and the Notch receptor, accumulate at the surface and in intracellular vesicles of cells mutant for VhaPRR. This trafficking defect is shared by other V‐ATPase subunits. By contrast, the V‐ATPase does not seem to have a direct role in PCP regulation. Together, our results suggest two roles for VhaPRR, one for PCP and another in endosomal trafficking. This dual function establishes VhaPRR as a key factor in epithelial morphogenesis. 相似文献
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Susan J. Harrison-Uy Julie A. Siegenthaler Andrea Faedo John L. R. Rubenstein Samuel J. Pleasure 《PloS one》2013,8(3)
We examined the role of the orphan nuclear hormone receptor CoupTFI in mediating cortical development downstream of meningeal retinoic acid signaling. CoupTFI is a regulator of cortical development known to collaborate with retinoic acid (RA) signaling in other systems. To examine the interaction of CoupTFI and cortical RA signaling we utilized Foxc1-mutant mice in which defects in meningeal development lead to alterations in cortical development due to a reduction of RA signaling. By analyzing CoupTFI−/−;Foxc1H/L double mutant mice we provide evidence that CoupTFI is required for RA rescue of the ventricular zone and the neurogenic phenotypes in Foxc1-mutants. We also found that overexpression of CoupTFI in Foxc1-mutants is sufficient to rescue the Foxc1-mutant cortical phenotype in part. These results suggest that CoupTFI collaborates with RA signaling to regulate both cortical ventricular zone progenitor cell behavior and cortical neurogenesis. 相似文献
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Samuel M. Imathiu Rumiana V. Ray Matthew I. Back Martin C. Hare Simon G. Edwards 《Journal of Phytopathology》2013,161(7-8):553-561
Fusarium langsethiae is a toxigenic fungal species that has been reported in European small‐grain cereal crops such as oats, wheat and barley. Although its relative contribution to fusarium head blight (FHB) symptoms is not well understood, it is reported to contaminate these cereals with high levels of HT‐2 and T‐2 trichothecenes mycotoxins that are currently under consideration for legislation by the European Commission. Ten commercial oat fields in Shropshire and Staffordshire (two adjacent counties in the Midlands) in the UK were surveyed in the 2006/2007 growing season. Samples were taken from predetermined field locations at Zadoks growth stages 32/33, 69, 77‐85 and 90‐92 for F. langsethiae biomass and HT‐2 and T‐2 toxins quantification. The results from this study showed that oats can be heavily infected with F. langsethiae and have high concentrations of HT‐2 and T‐2 toxins with no apparent FHB symptoms. The regression of HT‐2 + T‐2 toxins on F. langsethiae DNA concentration was highly significant (P < 0.001, r2 = 0.55). The results indicated that although F. langsethiae had no direct effect on crop yield, it may result in indirect economic losses where the grain can be rejected or downgraded as a result of intolerable levels of HT‐2 and T‐2 toxins, which are of human food and animal feed safety concern. The influence of cultural field practices on the infection and HT‐2 and T‐2 toxins accumulation in oats was not clear and warrants further studies to identify the sources of F. langsethiae inoculum and conditions favourable for infection and mycotoxin production. 相似文献
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Accounting for historical demographic features, such as the strength and timing of gene flow and divergence times between closely related lineages, is vital for many inferences in evolutionary biology. Approximate Bayesian computation (ABC) is one method commonly used to estimate demographic parameters. However, the DNA sequences used as input for this method, often microsatellites or RADseq loci, usually represent a small fraction of the genome. Whole genome sequencing (WGS) data, on the other hand, have been used less often with ABC, and questions remain about the potential benefit of, and how to best implement, this type of data; we used pseudo‐observed data sets to explore such questions. Specifically, we addressed the potential improvements in parameter estimation accuracy that could be associated with WGS data in multiple contexts; namely, we quantified the effects of (a) more data, (b) haplotype‐based summary statistics, and (c) locus length. Compared with a hypothetical RADseq data set with 2.5 Mbp of data, using a 1 Gbp data set consisting of 100 Kbp sequences led to substantial gains in the accuracy of parameter estimates, which was mostly due to haplotype statistics and increased data. We also quantified the effects of including (a) locus‐specific recombination rates, and (b) background selection information in ABC analyses. Importantly, assuming uniform recombination or ignoring background selection had a negative effect on accuracy in many cases. Software and results from this method validation study should be useful for future demographic history analyses. 相似文献
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Dennis T. Villareal Caroline M. Apovian Robert F. Kushner Samuel Klein 《Obesity (Silver Spring, Md.)》2005,13(11):1849-1863
Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age‐related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight‐management guidelines for obese older patients. The current data show that weight‐loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight‐loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss. 相似文献
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Reinhold Benesch Samuel Waxman Ruth Benesch Charles Baugh 《Biochemical and biophysical research communications》1982,106(4):1359-1363
Pteroyl polyglutamates bind to hemoglobin with an affinity which leaves only a minor fraction of red cell folate in the free state. This could serve as a regulating mechanism for protein synthesis in the differentiating erythroblast. 相似文献
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Biosynthesis of dihydromenaquinone-9 by Mycobacterium phlei 总被引:2,自引:0,他引:2