排序方式: 共有40条查询结果,搜索用时 234 毫秒
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黄檗丛枝菌根真菌鉴定 总被引:1,自引:0,他引:1
目的:利用形态学特征与Nested-PCR技术鉴定黄檗丛枝菌根真菌。方法:采用酸性品红染色法挑选黄檗丛枝菌根。同时,利用湿筛法获得AM真菌孢子,进行形态学鉴定。运用Nested-PCR技术,对黄檗粗提DNA进行特异性扩增,采用blastn进行序列相似性比较。并构建系统进化树,确定侵染黄檗根系的AM真菌。结果:编号为HDAM-1的AM真菌孢子,形态特征与G.intraradices的特征描述一致。Nested-PCR检测到约455bp的目的片段,其序列与G.intraradices(DQ469118)相似性最高,达97.8%,有11个碱基的差异。系统进化树显示该序列在基于25S rDNA的进化树中与G.intraradices(DQ469118.1)处于同一分支,确定G.intraradices侵染黄檗根系。结论:将形态学特征与Nested-PCR技术相结合鉴定AM真菌,不仅简易、经济,而且能够提高研究结果的可靠性。 相似文献
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Bayesian adaptive sequence alignment algorithms 总被引:3,自引:1,他引:2
The selection of a scoring matrix and gap penalty parameters continues to
be an important problem in sequence alignment. We describe here an
algorithm, the 'Bayes block aligner, which bypasses this requirement.
Instead of requiring a fixed set of parameter settings, this algorithm
returns the Bayesian posterior probability for the number of gaps and for
the scoring matrices in any series of interest. Furthermore, instead of
returning the single best alignment for the chosen parameter settings, this
algorithm returns the posterior distribution of all alignments considering
the full range of gapping and scoring matrices selected, weighing each in
proportion to its probability based on the data. We compared the Bayes
aligner with the popular Smith-Waterman algorithm with parameter settings
from the literature which had been optimized for the identification of
structural neighbors, and found that the Bayes aligner correctly identified
more structural neighbors. In a detailed examination of the alignment of a
pair of kinase and a pair of GTPase sequences, we illustrate the
algorithm's potential to identify subsequences that are conserved to
different degrees. In addition, this example shows that the Bayes aligner
returns an alignment-free assessment of the distance between a pair of
sequences.
相似文献
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TRANCE/TRAF6 signalling governs osteoclastogenesis in vivo. Only the TRANCE receptor (TRANCE-R) has been shown to induce osteoclastogenesis, even though other immune receptors, including CD40 and IL-1R/Toll-like receptor, use TRAF6 to activate overlapping signalling cascades. These observations led us to question whether qualitative or quantitative differences exist between the TRAF6-mediated signals induced by TRANCE and by other ligand-receptor pairs. Here we show that stimulation by overexpressed wild-type CD40 can induce osteoclastogenesis. Stimulation through modified CD40 containing increased numbers of TRAF6-binding sites in the cytoplasmic tails showed a dose-dependent increase in the activation of p38 kinase and more pronounced osteoclastogenesis. Moreover, precursors overexpressing TRAF6 differentiate into osteoclasts in the absence of additional signals from TRANCE. Our results suggest that differences in the osteoclastogenesis-inducing capacity of TRANCE-R versus other TRAF6-associated receptors may in part stem from a quantitative difference in the TRAF6-mediated signals. 相似文献
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Ingolf Sommer Stefano Toppo Oliver Sander Thomas Lengauer Silvio CE Tosatto 《BMC bioinformatics》2006,7(1):364
Background
In the area of protein structure prediction, recently a lot of effort has gone into the development of Model Quality Assessment Programs (MQAPs). MQAPs distinguish high quality protein structure models from inferior models. Here, we propose a new method to use an MQAP to improve the quality of models. With a given target sequence and template structure, we construct a number of different alignments and corresponding models for the sequence. The quality of these models is scored with an MQAP and used to choose the most promising model. An SVM-based selection scheme is suggested for combining MQAP partial potentials, in order to optimize for improved model selection. 相似文献38.
Background
The impressive increase of novel RNA structures, during the past few years, demands automated methods for structure comparison. While many algorithms handle only small motifs, few techniques, developed in recent years, (ARTS, DIAL, SARA, SARSA, and LaJolla) are available for the structural comparison of large and intact RNA molecules. 相似文献39.
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Some aromatic prostaglandin analogs, having a benzene (2a, 2b) and a dimethoxybenzene (1) ring in place of the cyclopentane moiety, have been synthesized. The key intermediates in the syntheses were lactols 9 and 5, which were elaborated to the final products via two olefination reactions. Compound 2b was twice as potent as phenylbutazone and nine times as potent as aspirin in inhibiting prostaglandin synthetase activity. 相似文献