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71.
Caldesmon and smooth-muscle regulation 总被引:5,自引:0,他引:5
Wang CL 《Cell biochemistry and biophysics》2001,35(3):275-288
Smooth muscles exist in the wall of hollow organs in our body and are responsible for controlling the flow of vital fluids
that are essential for the normal function of the cardiovascular, respiratory, digestive, and reproductive systems. Many diseases,
such as hypertension, asthma, indigestion, and premature birth, may attribute to malfunction of smooth-muscle contraction.
It is therefore important to decipher how smooth-muscle contraction is regulated. This review attempts to give a brief overview
of current understanding about the molecular mechanisms of smooth-muscle regulation and, in particular, to discuss possible
roles of caldesmon in this regulatory process. 相似文献
72.
The band 3 protein is the major integral protein present in the erythrocyte membrane. Two tissue-specific isoforms are also expressed in kidney alpha intercalated cells and in cardiomyocytes. It has been suggested that the cardiac isoform predominantly mediates the anion exchange in cardiomyocytes, but the role of the cytoplasmic domain of the band 3 (CDB3) protein in the cardiac tissue is unknown. In order to characterize novel associations of the CDB3 in the cardiac tissue, we performed the two-hybrid assay, using a bait comprising the region from leu 258 to leu 311 of the erythrocyte band 3, which must also be present in the cardiac isoform. The assay revealed two clones containing the C-terminal region of the alpha-cardiac actin. Immunoprecipitation of whole rat heart using an anti-actin antibody, immunoblotted with anti-human band 3, showed that actin binds to band 3 which was confirmed in the reverse assay. The confocal microscopy showed band 3 in the intercalated discs. Thus, besides the in vivo physical interaction in the Saccharomyces cerevisiae cell, we demonstrated using immunopreciptation that there is a physical association of band 3 with alpha-cardiac actin in cardiomyocyte, and we suggest that the binding occur "in situ," in the intercalated disc, a site of cell-cell contact and attachment of the sarcomere to the plasma membrane. 相似文献
73.
Wulf-Peter?SchmidtEmail author 《The International Journal of Life Cycle Assessment》2003,8(3):167-174
Background In developing products various requirements have to be integrated including functionality, quality, affordability as well
as environmental aspects. Often conflicting requirements have to be fulfilled. Therefore, multi-dimensional decision support
approaches are necessary.
Methods Here, one approach is to relate the conflicting requirements to each other. Life Cycle Costing (LCC) has the potential to
support the trade-off between some environmental targets and overall affordability targets by including all monetary flows
along the product life cycle (going beyond the well-known costs of ownership by integrating also long-term use and end-of-life
costs). Those solutions can be identified that (a) have the highest efficiencies (where do we get most environmental improvements
per Ϊ and (b) have the highest affordability for the customer along the life cycle. Furthermore, on-costs in the design phase
can be justified in terms of future savings either for the customer or for the recycling of the products. These represent
real business cases for environmental actions. Three types of environmental business cases can be differentiated.
Results and Discussion This paper presents various examples where LCC is integrated into product design. However, there are a number of open issues
in the implementation of LCC within real product development including data availability and uncertainty (future costs/ savings),
level of discounting, accounting and compensation. Various internal case studies done in the last years showed that already
few changes in the costs structure can significantly affect the identi-fied future costs.
Recommendation and Outlook Uncertainties in LCC are higher than in LCA and highest when applied in the stage of product develop-ment, i.e. used to support
DfE action. As a consequence, the result-ing figures can only be seen as directional. Therefore, the use of LCC in Design
for Environment cannot be recommended without major restrictions in terms of guidance, experience/training. The link-age between
LCC and DfE can either be established via (1) experts supporting design teams or (2) as part of a DfE tool. The DfE tool has
to include detailed guidance for interpretation, and its application should be based on a solid training for DfE engineers. 相似文献
74.
75.
A method was designed to produce rapidly (10–14 days) and directly (without intermediate callus) whole plants of Digitaria sanguinalis with a high yield without subculture. These plants developed from new structures, designated “pseudo-embryogenic structures”,
initiated only 1 week after the culture of tranverse thin cell layers (tTCLs), i.e., thin stem sections, on a Murashige and
Skoog medium containing 3% sucrose and a combination of a low concentration of 2,4-dichlorophenoxyacetic acid (1 μm) and a high concentration of 6-benzylaminopurine (10 μm). The fresh weight of plants regenerated per tTCL on gelrite was 6 times higher than with agar and 30 times higher than with
agarose.
Received: 25 August 1997 / Revision received: 18 February 1998 / Accepted: 10 March 1998 相似文献
76.
Prasert Sinsermsuksakul Leizhi Sun Sang Woon Lee Helen Hejin Park Sang Bok Kim Chuanxi Yang Roy G. Gordon 《Liver Transplantation》2014,4(15)
Thin‐film solar cells are made by vapor deposition of Earth‐abundant materials: tin, zinc, oxygen and sulfur. These solar cells had previously achieved an efficiency of about 2%, less than 1/10 of their theoretical potential. Loss mechanisms are systematically investigated and mitigated in solar cells based on p‐type tin monosulfide, SnS, absorber layers combined with n‐type zinc oxysulfide, Zn(O,S) layers that selectively transmit electrons, but block holes. Recombination at grain boundaries is reduced by annealing the SnS films in H2S to form larger grains with fewer grain boundaries. Recombination near the p‐SnS/n‐Zn(O,S) junction is reduced by inserting a few monolayers of SnO2 between these layers. Recombination at the junction is also reduced by adjusting the conduction band offset by tuning the composition of the Zn(O,S), and by reducing its free electron concentration with nitrogen doping. The resulting cells have an efficiency over 4.4%, which is more than twice as large as the highest efficiency obtained previously by solar cells using SnS absorber layers. 相似文献
77.
78.
《Journal of molecular biology》2021,433(13):167014
Much of our understanding of the homologous recombination (HR) machinery hinges on studies using Escherichia coli as a model organism. Interestingly enough, studies on the HR machinery in different bacterial species casts doubt on the universality of the E. coli paradigm. The human pathogen Mycobacterium tuberculosis encodes two Holliday junction (HJ)‐resolvase paralogues, namely RuvC and RuvX; however, insights into their structural features and functional relevance is still limited. Here, we report on structure-guided functional studies of the M. tuberculosis RuvX HJ resolvase (MtRuvX). The crystalline MtRuvX is a dimer in the asymmetric unit, and each monomer has a RNAse H fold vis-à-vis RuvC-like nucleases. Interestingly, MtRuvX also contains some unique features, including the residues essential for ATP binding/coordination of Mg2+ ions. Indeed, MtRuvX exhibited an intrinsic, robust ATPase activity, which was further accentuated by DNA cofactors. Structure-guided substitutions of single residues at the ATP binding/Mg2+coordination sites while markedly attenuating the ATPase activity completely abrogated HJ cleavage, indicating an unanticipated relationship between ATP hydrolysis and DNA cleavage. However, the affinity of ATPase-deficient mutants for the HJ was not impaired. Contrary to RuvC, MtRuvX exhibits relaxed substrate specificity, cleaving a variety of branched DNA/RNA substrates. Notably, ATP hydrolysis plays a regulatory role, rendering MtRuvX from a canonical HJ resolvase to a DNA/RNA non-sequence specific endonuclease, indicating a link between HJ resolvase and nucleic acid metabolism. These findings provide novel insights into the structure and dual-functional activities of MtRuvX, and suggest that it may play an important role in DNA/RNA metabolism. 相似文献
79.
80.
This paper describes a joint study of the structure and nonlinear optical properties of vacuum evaporated thin films of copper phthalocyanine (CuPc for brevity). Film thickness ranges from 50 to 500 nm. The anisotropic paramagnetic resonance of Cu++ ions reveals that the Pc rings lie almost parallel to the substrate plane with however a large angular distribution (30° FWHM). Third harmonic optical generation measurements performed at 1.064 m and 1.907 m fundamental wavelengths give respectively an average value of the cubic susceptibility (3)(-3,)=(4±0.4)·10–12 e.s.u. and (2.1+-0.2) · 10-12 These values, although significantly higher than for a common ionic crystal, are about one order of magnitude lower than in conjugated 1-D systems, which shows that the 2-D -electron delocalization is less profitable than the 1-D one. Besides third harmonic, we have also observed second harmonic generation. Its polarization dependence is characteristic of a quadratic susceptibility enhanced in one direction, almost perpendicular to the substrate, withd
eff comprised between 30 and 60 · 10-9 e.s.u. The possible origins ofd
eff are discussed. 相似文献