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151.
Monnard PA 《Cellular and molecular life sciences : CMLS》2005,62(5):520-534
Micro- and nanoenvironments formed by amphiphile self-assembled structures, water-ice lattices and minerals have well-defined, repeating, chemical and physical properties that can be used for selective synthesis of biopolymers, such as RNAs and proteins. The advances made in the development of polymerization supported by these micro- and nanosystems are reviewed here. In particular, it is shown that these systems promote non-enzymatic biopolymerization, yielding long polymers whose sequence composition is determined by the interactions between monomers and the supporting environment. When used to compartmentalize enzymatic biopolymerization, micro- and nanostructures allow the implementation of molecular selection and evolution schemes, which are difficult in homogeneous medium, yielding very active molecules. Thus, micro- and nanoenvironment approaches to the synthesis and selection of biopolymers could be developed into a new biotechnological tool for the production of biopolymers with novel functions.Received 3 August 2004; received after revision 6 October 2004; accepted 21 October 2004 相似文献
152.
Dewji NN 《Cellular and molecular life sciences : CMLS》2005,62(10):1109-1119
The presenilins (PSs) were new proteins discovered in 1995 to be involved, among other functions, in the molecular mechanisms leading to Alzheimers disease. These proteins have been the subject of many investigations since then to elucidate their molecular structures and functions. Until now, the conclusions about PS structure have been discordant, but the 8-TM structure has been accepted by the Alzheimers community, with the evidence for the 7-TM structure largely ignored. Here the evidence is reviewed for the 6-TM, 7-TM, 8-TM and other proposed models of PS topography and possibilities offered for the differences in interpretation of the various sets of data. The conclusion is that at this stage, the 7-TM model for cell surface PS is most likely the correct one.Received 22 December 2004; accepted 26 January 2005 相似文献
153.
Role of Sam68 as an adaptor protein in signal transduction 总被引:3,自引:0,他引:3
Najib S Martín-Romero C González-Yanes C Sánchez-Margalet V 《Cellular and molecular life sciences : CMLS》2005,62(1):36-43
Sam68, the substrate of Src in mitosis, belongs to the family of RNA binding proteins. Sam68 contains consensus sequences to interact with other proteins via specific domains. Thus, Sam68 has various proline-rich sequences to interact with SH3 domain-containing proteins. Moreover, Sam68 also has a C-terminal domain rich in tyrosine residues that is a substrate for tyrosine kinases. Tyrosine phosphorylation of Sam68 promotes its interaction with SH2 containing proteins. The association of Sam68 with SH3 domain-containing proteins, and its tyrosine phosphorylation may negatively regulate its RNA binding activity. The presence of these consensus sequences to interact with different domains allows this protein to participate in signal transduction pathways triggered by tyrosine kinases. Thus, Sam68 participates in the signaling of T cell receptors, leptin and insulin receptors. In these systems Sam68 is tyrosine phosphorylated and recruited to specific signaling complexes. The participation of Sam68 in signaling suggests that it may function as an adaptor molecule, working as a dock to recruit other signaling molecules. Finally, the connection between this role of Sam68 in protein-protein interaction with RNA binding activity may connect signal transduction of tyrosine kinases with the regulation of RNA metabolism.Received 16 July 2004; received after revision 12 August 2004; accepted 18 August 2004 相似文献
154.
155.
Xiaoning Li Xing Yang Xujie Liu Wei He Qianli Huang Shengrong Li Qingling Feng 《自然科学进展(英文版)》2018,28(5):598-608
Rhombohedron-like and fusiform calcium carbonate nanoparticles were fabricated using a new method. Their geometry was controlled by varying the mixing speed and ratio of ethanol versus water in reaction system. The calcium carbonate nanoparticles(CCNPs) have slight effect on viability of human bone-marrow mesenchymal stem cells(hBMSCs) with dose-dependent and shape-dependent, but they can significantly promote osteogenic differentiation of hBMSCs in vitro by 10–37% increase of alkaline phosphatase(ALP) activity, 9–36% growth of collagen secretion and 1.13–1.83 folds upregulation of osteogenesis-related genes, even at lower dose ranges(5–20 μg/ml). The efficacity of promoting osteogenesis depends on the shape and dose of CCNPs. Furthermore,adipogenesis was inhibited by less accumulation of lipid droplets, lower triglyceride(TG) secretion and downregulation of adipogenesis-related genes. These findings improve the understanding of effects CCNPs on hBMSCs fate towards osteoblasts or adipocytes and have meaningful impact for combining use of CCNPs and hBMSCs in tissue engineering and regenerative medicine fields. 相似文献
156.
D. Robinette S. Wada T. Arroll M. G. Levy W. L. Miller E. J. Noga 《Cellular and molecular life sciences : CMLS》1998,54(5):467-475
Three antibacterial proteins were isolated from acid extracts of channel catfish (Ictalurus punctatus) skin by cation exchange chromatography and reverse-phase high-pressure liquid chromatography. The molecular masses of the
proteins were 15.5, 15.5 and 30 kD as determined by SDS-polyacrylamide gel electrophoresis. Mass spectrometry, amino acid
composition and amino acid sequence data suggest that the most abundant protein is closely related to histone H2B. The H2B-like
protein was inhibitory to Aeromonas hydrophila and Saprolegnia spp., which are important bacterial and fungal pathogens of fish. These findings suggest that histones may be important defensive
molecules in fish.
Received 22 December 1997; received after revision 5 March 1998; accepted 5 March 1998 相似文献
157.
158.
花生(Arachis hypogea L.)体细胞胚胚性特异蛋白的研究 总被引:2,自引:0,他引:2
花生萌发3d的胚叶在诱导培养基上出现高频率的体细胞胚发生.SDS-PAGE分析结果表明:在体细胞胚发生过程中,诱导第三天开始出现3条新的蛋白谱带,7d后出现2条新带,15d后又出现3条;而在非胚性组织中检测到抑制性的特异蛋白条带. 相似文献
159.
Haiping Kou Songsen Chen Weidong Chen Jingqiu Zhang Xu Di Zhiquan Liang 《科学通报(英文版)》1999,44(17):1576-1576
By electrophoretic mobility shift assay (EMSA), the effect of point mutation C→T at - 64 of human δ-globin gene on its binding proteins has been studied. Two segments of 36 bp from - 83- - 48 bp of the 6 globin gene promoter, named WOG and MOG, were synthesized. WOG includes wild type CAAT-like box (CCAAC), while MOG includes the mutant CAAT-like box (CCAAT, -64 C→T). Results indicate that: ( i ) in erythroid cell lines MEL, K562 and Hemin induced K562, the affinity of MOG with CCAAT binding protein (CBF) and GATA-1 was greatly increased; ( ii ) in Hemin induced K562 cell line, there were another two novel specific DNA binding proteins, named C and D temporarily, besides the above two factors. The former was combined with WOG and MOG, likely indicating its relation with the increased gene expression after induction. The latter was only combined with MOG, which had possible relationship with the point mutation of - 64 C→T; ( iii ) EMSA also indicates that the suppression mechanisms of the expression of 6 globin gene is different in various periods of human developments. The result evidently supports the hypothesis that the defect CAAT-like box in human 6 globin gene contributes the main reason of its low level expression. The defect c/s-acting element CAAT-like box affects gene expression by its combination with the frans-acting element CBF and GATA-1. 相似文献
160.
纤毛虫皮层的研究对探讨细胞的发育、分化、结构模式及其遗传控制有着极其重大的生物学意义,纤毛虫细胞皮层中含有非常丰富的细胞骨架成分,它们在结构上表现出来的特殊性有利于更深地探索皮层分化和皮层模式的控制机理,本综述了有关纤毛虫皮层细胞骨架的结构和形态发生方面的研究及皮层细胞骨架蛋白质构成的生化和分子生物学研究进展。 相似文献