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41.
Assembly of the sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures: localization by immunofluorescence of sarcoplasmic reticulum proteins in differentiating rat skeletal muscle cell cultures 下载免费PDF全文
Immunofluorescent staining techniques were used to study the distribution of the Ca(2) + Mg(2+)-dependent ATPase and calsequestrin in primary cultures of differentiating rat skeletal muscle cells, grown for different periods of time under various culture conditions. In mononucleated myoblasts calsequestrin was detected after 45 h in culture whereas the ATPase was not detected until 60 h. After cell fusion began, both proteins could be identified in all multinucleated cells. Myoblasts grown for longer than 60 h in low Ca(2+) medium contained calsequestrin and the ATPase, even though they were unable to fuse. These studies at the cellular level confirm biochemical findings on the biosynthesis of calsequestrin and the ATPase. Immunofluorescent staining of myoblasts showed that calsequestrin first appears in a well-defined region of the cell near one end of the nucleus. At later times, the staining occupied progressively larger regions adjacent to the nucleus and took on a fibrous appearance. This suggests that calsequestrin first accumulates in the Golgi region and then gradually spreads throughout the cell. In contrast, the ATPase appeared to be concentrated in many small patches or foci throughout the cytoplasm and was never confined to one particular region, although some parts of the cell often stained more intensely than others. In multinucleated cells, alternating dark and fluorescent strands parallel to the longitudinal axis of the cells were evident. 相似文献
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Role of cryptic genes in microbial evolution 总被引:24,自引:1,他引:23
Cryptic genes are phenotypically silent DNA sequences, not normally
expressed during the life cycle of an individual. They may, however, be
activated in a few individuals of a large population by mutation,
recombination, insertion elements, or other genetic mechanisms. A
consideration of the microbial literature concerning biochemical evolution,
physiology, and taxonomy provides the basis for a hypothesis of microbial
adaptation and evolution by mutational activation of cryptic genes.
Evidence is presented, and a mathematical model is derived, indicating that
powerful and biologically important mechanisms exist to prevent the loss of
cryptic genes. We propose that cryptic genes persist as a vital element of
the genetic repertoire, ready for recall by mutational activation in future
generations. Cryptic genes provide a versatile endogenous genetic reservoir
that enhances the adaptive potential of a species by a mechanism that is
independent of genetic exchange.
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Ethan DH Kim Ashish Sabharwal Adrian R Vetta Mathieu Blanchette 《Algorithms for molecular biology : AMB》2010,5(1):34
Background
Affinity purification followed by mass spectrometry identification (AP-MS) is an increasingly popular approach to observe protein-protein interactions (PPI) in vivo. One drawback of AP-MS, however, is that it is prone to detecting indirect interactions mixed with direct physical interactions. Therefore, the ability to distinguish direct interactions from indirect ones is of much interest. 相似文献48.
SplitsTree: analyzing and visualizing evolutionary data 总被引:15,自引:0,他引:15
MOTIVATION: Real evolutionary data often contain a number of different and
sometimes conflicting phylogenetic signals, and thus do not always clearly
support a unique tree. To address this problem, Bandelt and Dress (Adv.
Math., 92, 47-05, 1992) developed the method of split decomposition. For
ideal data, this method gives rise to a tree, whereas less ideal data are
represented by a tree-like network that may indicate evidence for different
and conflicting phylogenies. RESULTS: SplitsTree is an interactive program,
for analyzing and visualizing evolutionary data, that implements this
approach. It also supports a number of distances transformations, the
computation of parsimony splits, spectral analysis and bootstrapping.
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