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871.
S. Kjellev 《Cellular and molecular life sciences : CMLS》2009,66(8):1350-1369
The trefoil factor family (TFF) comprises a group of small peptides which are highly expressed in tissues containing mucus-producing
cells – especially in the mucosa lining the gastrointestinal tract. The peptides seem crucial for epithelial restitution and
may work via other pathways than the conventional factors involved in restitution. In vitro studies have shown that the TFFs promote restitution using multiple mechanisms. The peptides also have other functionalities
including interactions with the immune system. Moreover, therapeutic effects of the TFFs have been shown in several animal
models of gastrointestinal damage. Still it is not clear which of their in vitro properties are involved in the in vivo mode of action. This review describes the TFF family with emphasis on their biological properties and involvement in mucosal
protection and repair.
Received 10 October 2008; received after revision 07 November 2008; accepted 10 November 2008 相似文献
872.
A. Shukla P. Chaurasia S. R. Bhaumik 《Cellular and molecular life sciences : CMLS》2009,66(8):1419-1433
Methylation of lysine residues of histones is associated with functionally distinct regions of chromatin, and, therefore,
is an important epigenetic mark. Over the past few years, several enzymes that catalyze this covalent modification on different
lysine residues of histones have been discovered. Intriguingly, histone lysine methylation has also been shown to be cross-regulated
by histone ubiquitination or the enzymes that catalyze this modification. These covalent modifications and their cross-talks
play important roles in regulation of gene expression, heterochromatin formation, genome stability, and cancer. Thus, there
has been a very rapid progress within past several years towards elucidating the molecular basis of histone lysine methylation
and ubiquitination, and their aberrations in human diseases. Here, we discuss these covalent modifications with their cross-regulation
and roles in controlling gene expression and stability.
Received 24 September 2008; received after revision 21 November 2008; accepted 28 November 2008 相似文献
873.
The elucidation of assembly pathways of multi-subunit membrane proteins is of growing interest in structural biology. In this
study, we provide an analysis of the assembly of the asymmetrically oriented PsaC subunit on the pseudo C2-symmetric Photosystem I core. Based on a comparison of the differences in the NMR solution structure of unbound PsaC with
that of the X-ray crystal structure of bound PsaC, and on a detailed analysis of the PsaC binding site surrounding the FX iron-sulfur cluster, two models can be envisioned for what are likely the last steps in the assembly of Photosystem I. Here,
we dissect both models and attempt to address heretofore unrecognized issues by proposing a mechanism that includes a thermodynamic
perspective. Experimental strategies to verify the models are proposed. In closing, the evolutionary aspects of the assembly
process will be considered, with special reference to the structural arrangement of the PsaC binding surface.
Received 22 October 2008; received after revision 17 November 2008; accepted 05 December 2008 相似文献
874.
借鉴经典动力学中约束力的思想,提出了一种编队卫星构形精确保持的非线性控制方法.该方法首先将非线性和摄动条件下编队卫星构形保持问题转换为带有完整约束的拉格朗日动力学系统,然后将问题转换为一组微分代数方程,通过求解微分代数方程,确定编队卫星构形保持的非线性控制律.由于借鉴了约束力的思想,该方法自然地利用了编队卫星动力学系统的力学特性,具有节省能量和高精度的特点.通过对线性和非线性条件下空间圆编队卫星构形保持问题的仿真,验证了提出的非线性控制方法的这些特性. 相似文献
875.
Wolfs JL Comfurius P Bekers O Zwaal RF Balasubramanian K Schroit AJ Lindhout T Bevers EM 《Cellular and molecular life sciences : CMLS》2009,66(2):314-323
The exposure of phosphatidylserine (PS) at the cell surface plays a critical role in blood coagulation and serves as a macrophage
recognition moiety for the engulfment of apoptotic cells. Previous observations have shown that a high extracellular [K+] and selective K+ channel blockers inhibit PS exposure in platelets and erythrocytes. Here we show that the rate of PS exposure in erythrocytes
decreases by ~50% when the intracellular [K+] increases from 0 to physiological concentrations. Using resealed erythrocyte membranes, we further show that lipid scrambling
is inducible by raising the intracellular [Ca2+] and that K+ ions have a direct inhibitory effect on this process. Lipid scrambling in resealed ghosts occurs in the absence of cell shrinkage
and microvesicle formation, processes that are generally attributed to Ca2+-induced lipid scrambling in intact erythrocytes. Thus, opening of Ca2+-sensitive K+ channels causes loss of intracellular K+ that results in reduced intrinsic inhibitory effect of these ions on scramblase activity.
Received 11 September 2008; received after revision 17 October 2008; accepted 27 October 2008 相似文献
876.
J. Kim D. C. Han J. M. Kim S. Y. Lee S. J. Kim J. R. Woo J. W. Lee S.-K. Jung K. S. Yoon H. G. Cheon S. S. Kim S. H. Hong B.-M. Kwon 《Cellular and molecular life sciences : CMLS》2009,66(10):1766-1781
Indenone KR-62776 acts as an agonist of PPARγ without inducing obesity in animal models and cells. X-ray crystallography reveals
that the indenone occupies the binding pocket in a different manner than rosiglitazone. 2-Dimensional gel-electrophoresis
showed that the expression of 42 proteins was altered more than 2.0-fold between KR-62776- or rosiglitazone-treated adipocyte
cells and control cells. Rosiglitazone down-regulated the expression of ERK1/2 and suppressed the phosphorylation of ERK1/2
in these cells. However, the expression of ERK1/2 was up-regulated in KR-62776-treated cells. Phosphorylated ERK1/2, activated
by indenone, affects the localization of PPARγ, suggesting a mechanism for indenone-inhibition of adipogenesis in 3T3-L1 preadipocyte
cells. The preadipocyte cells are treated with ERK1/2 inhibitor PD98059, a large amount of the cells are converted to adipocyte
cells. These results support the conclusion that the localization of PPARγ is one of the key factors explaining the biological
responses of the ligands.
Received 04 March 2009; received after revision 13 March 2009; accepted 17 March 2009 相似文献
877.
Large conductance, Ca2+-activated potassium (BK) channels are widely expressed throughout the animal kingdom and play important roles in many physiological
processes, such as muscle contraction, neural transmission and hearing. These physiological roles derive from the ability
of BK channels to be synergistically activated by membrane voltage, intracellular Ca2+ and other ligands. Similar to voltage-gated K+ channels, BK channels possess a pore-gate domain (S5–S6 transmembrane segments) and a voltage-sensor domain (S1–S4). In addition,
BK channels contain a large cytoplasmic C-terminal domain that serves as the primary ligand sensor. The voltage sensor and
the ligand sensor allosterically control K+ flux through the pore-gate domain in response to various stimuli, thereby linking cellular metabolism and membrane excitability.
This review summarizes the current understanding of these structural domains and their mutual interactions in voltage-, Ca2+ - and Mg2+ -dependent activation of the channel.
Received 25 September 2008; received after revision 23 October 2008; accepted 24 October 2008 相似文献
878.
Dynamic protein methylation in chromatin biology 总被引:1,自引:1,他引:0
879.
Learning organisation literature has widely discussed the connections between “double-loop” learning and its significance to organisational performance, but paying little attention to tools and systems that can operationalise “double-loop” learning in organisations. This paper investigates the impact of applying a systems approach for service operations design, expressed as the Vanguard Method (Seddon, Freedom from command and control: a better way to make the work work, 2003), in order to activate “double-loop” learning in service organisations. Two case studies were conducted in the banking mortgage operations and adults’ social care services in the UK, using the dimensions of the learning organisation questionnaire (DLOQ), semi-structured interviews, observations, and documents. The findings of the cross-case analysis support the link of applying the Vanguard Method with operationalising “double-loop” learning through three main factors, namely systematic-operations improvement, organisational capacity development, and outside-in mode of work; that are all embedded into the seven dimensions of the DLOQ. The value of this paper is the introduction of a service operations design tool that can activate “double-loop” learning performance in the fast changing knowledge era. It also provides an impetus for service organisations to creatively influence employees’ competencies to effectively improve internal systems. 相似文献
880.
Shirin Kalyan Vijayanand Chandrasekaran Elgar S. Quabius Thisbe K. Lindhorst Dieter Kabelitz 《Cellular and molecular life sciences : CMLS》2014,71(12):2335-2346
Nitrogen-bisphosphonates (n-BP), such as zoledronate, are the main class of drugs used for the prevention of osteoporotic fractures and the management of cancer-associated bone disease. However, long-term or high-dose use has been associated with certain adverse drug effects, such as osteonecrosis of the jaw and the loss of peripheral of blood Vγ9Vδ2 T cells, which appear to be linked to drug-induced immune dysfunction. In this report we show that neutrophils present in human peripheral blood readily take up zoledronate, and this phenomenon is associated with the potent immune suppression of human peripheral blood Vγ9Vδ2 T cells. Furthermore, we found this zoledronate-mediated inhibition by neutrophils could be overcome to fully reconstitute Vγ9Vδ2 T cell proliferation by concomitantly targeting neutrophil-derived hydrogen peroxide, serine proteases, and arginase I activity. These findings will enable the development of targeted strategies to mitigate some of the adverse effects of n-BP treatment on immune homeostasis and to improve the success of immunotherapy trials based on harnessing the anticancer potential of peripheral blood γδ T cells in the context of n-BP treatment. 相似文献