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1.
Background
Phylogenies capture the evolutionary ancestry linking extant species. Correlations and similarities among a set of species are mediated by and need to be understood in terms of the phylogenic tree. In a similar way it has been argued that biological networks also induce correlations among sets of interacting genes or their protein products. 相似文献2.
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南瓜雌蕊与自花及远缘花粉的相互作用 总被引:2,自引:0,他引:2
南瓜柱头表面经去垢剂、蛋白酶及Con A处理后花粉不能萌发或花粉管生长受阻,Con A能专一地与柱头表面结合。柱头块加入培养液可促进花粉萌发。不同的远缘花粉授粉后在雌蕊不同部位受阻。在成熟南瓜雌蕊提取液中检测到血凝活性,凝集素可能参与雌蕊对远缘花粉的抑制。 相似文献
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BACKGROUND: Fractionated plasma metanephrine measurements are commonly used in biochemical testing in search of pheochromocytoma. METHODS: We aimed to critically appraise the diagnostic efficacy of fractionated plasma free metanephrine measurements in detecting pheochromocytoma. Nine electronic databases, meeting abstracts, and the Science Citation Index were searched and supplemented with previously unpublished data. Methodologic and reporting quality was independently assessed by two endocrinologists using a checklist developed by the Standards for Reporting of Diagnostic Studies Accuracy Group and data were independently abstracted. RESULTS: Limitations in methodologic quality were noted in all studies. In all subjects (including those with genetic predisposition): the sensitivities for detection of pheochromocytoma were 96%-100% (95% CI ranged from 82% to 100%), whereas the specificities were 85%-100% (95% CI ranged from 78% to 100%). Statistical heterogeneity was noted upon pooling positive likelihood ratios when those with predisposition to disease were included (p < 0.001). However, upon pooling the positive or negative likelihood ratios for patients with sporadic pheochromocytoma (n = 191) or those at risk for sporadic pheochromocytoma (n = 718), no statistical heterogeneity was noted (p = 0.4). For sporadic subjects, the pooled positive likelihood ratio was 5.77 (95% CI = 4.90, 6.81) and the pooled negative likelihood ratio was 0.02 (95% CI = 0.01, 0.07). CONCLUSION: Negative plasma fractionated free metanephrine measurements are effective in ruling out pheochromocytoma. However, a positive test result only moderately increases suspicion of disease, particularly when screening for sporadic pheochromocytoma. 相似文献
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de Graaf C Oostenbrink C Keizers PH van Vugt-Lussenburg BM Commandeur JN Vermeulen NP 《European biophysics journal : EBJ》2007,36(6):589-599
Detailed molecular dynamics (MD) simulations have been performed to reproduce and rationalize the experimental finding that
the F483A mutant of CYP2D6 has lower affinity for R-propranolol than for S-propranolol. Wild-type (WT) CYP2D6 does not show this stereospecificity. Four different approaches to calculate the free
energy differences have been investigated and were compared to the experimental binding data. From the differences between
calculations based on forward and backward processes and the closure of thermodynamic cycles, it was clear that not all simulations
converged sufficiently. The approach that calculates the free energies of exchanging R-propranolol with S-propranolol in the F483A mutant relative to the exchange free energy in WT CYP2D6 accurately reproduced the experimental
binding data. Careful inspection of the end-points of the MD simulations involved in this approach, allowed for a molecular
interpretation of the observed differences.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Dasgupta S Hu X Keizers PH Liu WM Luchinat C Nagulapalli M Overhand M Parigi G Sgheri L Ubbink M 《Journal of biomolecular NMR》2011,51(3):253-263
Calmodulin is a two-domain protein which in solution can adopt a variety of conformations upon reorientation of its domains.
The maximum occurrence (MO) of a set of calmodulin conformations that are representative of the overall conformational space
possibly sampled by the protein, has been calculated from the paramagnetism-based restraints. These restraints were measured
after inclusion of a lanthanide binding tag in the C-terminal domain to supplement the data obtained by substitution of three
paramagnetic lanthanide ions to the calcium ion in the second calcium binding loop of the N-terminal domain. The analysis
shows that the availability of paramagnetic restraints arising from metal ions placed on both domains, reduces the MO of the
conformations to different extents, thereby helping to identify those conformations that can be mostly sampled by the protein. 相似文献