排序方式: 共有38条查询结果,搜索用时 15 毫秒
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Dynamic anatomy of the ulnar nerve at the elbow 总被引:1,自引:0,他引:1
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William J Holmes Richard AJ Darby Martin DB Wilks Rodney Smith Roslyn M Bill 《Microbial cell factories》2009,8(1):35-14
Background
The optimisation and scale-up of process conditions leading to high yields of recombinant proteins is an enduring bottleneck in the post-genomic sciences. Typical experiments rely on varying selected parameters through repeated rounds of trial-and-error optimisation. To rationalise this, several groups have recently adopted the 'design of experiments' (DoE) approach frequently used in industry. Studies have focused on parameters such as medium composition, nutrient feed rates and induction of expression in shake flasks or bioreactors, as well as oxygen transfer rates in micro-well plates. In this study we wanted to generate a predictive model that described small-scale screens and to test its scalability to bioreactors. 相似文献34.
Phylogenetic relationships of bolitoglossine salamanders: a demonstration of the effects of combining morphological and molecular data sets 总被引:2,自引:0,他引:2
We analyzed sequence data for 555 bp of the mitochondrial gene cytochrome b
in plethodontid salamanders, taken from 18 ingroup (tribe Bolitoglossini)
and 4 outgroup (tribe Plethodontini) taxa. There were 257 variable sites,
of which 219 were phylogenetically informative. Sequence differences among
taxa exceeded 20%, and there were up to 15% amino acid differences among
the sequences. We also analyzed 37 morphological (including karyological)
characters, taken from the literature. Data were analyzed separately and
then combined using parsimony and likelihood approaches. There is little
conflict between the morphological and DNA data, and that which occurs is
at nodes that are weakly supported by one or both of the data sets. Treated
separately, the morphological and DNA data provide strong support for some
nodes but not for others. The combined data act synergistically so that
good support is obtained for nearly all of the nodes in the tree. Recent
divergences are supported by silent transitions, and older divergences are
supported by a combination of morphological, karyological, DNA
transversion, and amino acid changes. Eliminating silent changes from the
DNA data improves the consistency index and improves some bootstrap and
decay index values for several deeper branches in the tree. However, the
combined data set with all characters included provides a better supported
tree overall. Maximum likelihood and parsimony with all of the data give
not only the same topology but also remarkably similar branch lengths.
Results of this analysis support the monopoly of the supergenera
Hydromantes and Batrachoseps, and of a sister group relationship of
Batrachoseps and the supergenus Bolitoglossa (represented in this study one
species of the genus Bolitoglossa).
相似文献
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DC White JO Stair DB Ringelberg 《Journal of industrial microbiology & biotechnology》1996,17(3-4):185-196
Microscopic examinations have convinced microbial ecologists that the culturable microbes recovered from environmental samples represent a tiny proportion of the extant microbiota. Methods for recovery and enzymatic amplification of nucleic acids from environmental samples have shown that a huge diversity existsin situ, far exceeding any expectations which were based on direct microscopy. It is now theoretically possible to extract, amplify and sequence all the nucleic acids from a community and thereby gain a comprehensive measure of the diversity as well as some insights into the phylogeny of the various elements within this community. Unfortunately, this analysis becomes economically prohibitive if applied to the multitude of niches in a single biome let alone to a diverse set of environments. It is also difficult to utilize PCR amplification on nucleic acids from some biomes because of coextracting enzymatic inhibitors. Signature biomarker analysis which potentially combines gene probe and lipid analysis on the same sample, can serve as a complement to massive environmental genome analysis in providing quantitative comparisons between microniches in the biome under study. This analysis can also give indications of the magnitude of differences in biodiversity in the blome as well as provide insight into the phenotypic activities of each community in a rapid and cost-effective manner. Applications of signature lipid biomarker analysis to define quantitatively the microbial viable biomass of portions of an Eastern USA deciduous forest, are presented. 相似文献
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