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31.
Minjuan Shen Mingli Lin Mengqi Zhu Wenxin Zhang Danyang Lu Huanhuan Liu Jingjing Deng Kehua Que Xu Zhang 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):167-181
Since their discovery, matrix vesicles (MVs) containing minerals have received considerable attention for their role in the mineralization of bone, dentin and calcified cartilage. Additionally, MVs' association with collagen fibrils, which serve as the scaffold for calcification in the organic matrix, has been repeatedly highlighted. The primary purpose of the present study was to establish a MVs–mimicking model (PEG-S-ACP/micelle) in vitro for studying the exact mechanism of MVs-mediated extra/intra fibrillar mineralization of collagen in vivo. In this study, high-concentration serine was used to stabilize the amorphous calcium phosphate (S-ACP), which was subsequently mixed with polyethylene glycol (PEG) to form PEG-S-ACP nanoparticles. The nanoparticles were loaded in the polysorbate 80 micelle through a micelle self-assembly process in an aqueous environment. This MVs–mimicking model is referred to as the PEG-S-ACP/micelle model. By adjusting the pH and surface tension of the PEG-S-ACP/micelle, two forms of minerals (crystalline mineral nodules and ACP nanoparticles) were released to achieve the extrafibrillar and intrafibrillar mineralization, respectively. This in vitro mineralization process reproduced the mineral nodules mediating in vivo extrafibrillar mineralization and provided key insights into a possible mechanism of biomineralization by which in vivo intrafibrillar mineralization could be induced by ACP nanoparticles released from MVs. Also, the PEG-S-ACP/micelle model provides a promising methodology to prepare mineralized collagen scaffolds for repairing bone defects in bone tissue engineering. 相似文献
32.
Patterns of Sleeping Site and Sleeping Tree Selection by Black-and-Gold Howler Monkeys (Alouatta caraya) in Northern Argentina 总被引:1,自引:0,他引:1
Brividoro Melina V. Kowalewski Martin M. Scarry Clara J. Oklander Luciana I. 《International journal of primatology》2019,40(3):374-392
International Journal of Primatology - The selection of sleeping sites and sleeping trees in nonhuman primates is related to social and ecological factors. We investigate the role of body... 相似文献
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Properties of a transient current (Icont) believed to reflect a conformational change of the Na-Ca exchanger molecules after Ca2+ binding were investigated. Intracellular Ca2+ concentration jumps in isolated cardiac myocytes were generated with flash photolysis of caged Ca2+ dimethoxynitrophenamine, and membrane currents were simultaneously measured using the whole-cell variant of the patch-clamp technique. A previously unresolved shallow voltage dependence of Icont was revealed after developing an experimental protocol designed to compensate for the photoconsumption of the caged compound. This voltage dependence can be interpreted to reflect the distribution of Na-Ca exchanger conformational states with the Ca2+ binding site exposed to the inside of the cell immediately before the flash. Analysis performed by fitting a Boltzmann distribution to the observed data suggests that under control conditions most exchanger molecules reside in states with the Ca2+ binding site facing the outside of the cell. Dialysis of the cytosol with 3',4'-dichlorobenzamil, an organic inhibitor of the Na-Ca exchange, increased the magnitude of Icont and changed the voltage dependence, consistent with a parallel shift of the charge/voltage curve. This shift may result from intracellular DCB interfering with an Na(+)-binding or Na(+)-translocating step. These observations are consistent with Icont arising from a charge movement mediated by the Na-Ca exchanger molecules after binding of Ca2+. 相似文献
35.
Epstein-Barr virus transformation of human B lymphocytes despite inhibition of viral polymerase. 总被引:3,自引:3,他引:0
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Epstein-Barr virus transformed human lymphocytes despite the presence of up to 500 microM acyclovir [9-(2-hydroxyethoxymethyl)guanine], a viral DNA polymerase inhibitor. The transformed cells contained multiple Epstein-Barr virus genome copy numbers. Functional viral DNA polymerase is probably not required for cell transformation and the initial amplification of the viral genome. 相似文献
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Victoria V. Hargreaves Scarlet S. Shell Dan J. Mazur Martin T. Hess Richard D. Kolodner 《The Journal of biological chemistry》2010,285(12):9301-9310
Indirect evidence has suggested that the Msh2-Msh6 mispair-binding complex undergoes conformational changes upon binding of ATP and mispairs, resulting in the formation of Msh2-Msh6 sliding clamps and licensing the formation of Msh2-Msh6-Mlh1-Pms1 ternary complexes. Here, we have studied eight mutant Msh2-Msh6 complexes with defective responses to nucleotide binding and/or mispair binding and used them to study the conformational changes required for sliding clamp formation and ternary complex assembly. ATP binding to the Msh6 nucleotide-binding site results in a conformational change that allows binding of ATP to the Msh2 nucleotide-binding site, although ATP binding to the two nucleotide-binding sites appears to be uncoupled in some mutant complexes. The formation of Msh2-Msh6-Mlh1-Pms1 ternary complexes requires ATP binding to only the Msh6 nucleotide-binding site, whereas the formation of Msh2-Msh6 sliding clamps requires ATP binding to both the Msh2 and Msh6 nucleotide-binding sites. In addition, the properties of the different mutant complexes suggest that distinct conformational states mediated by communication between the Msh2 and Msh6 nucleotide-binding sites are required for the formation of ternary complexes and sliding clamps. 相似文献
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B Spyropoulos P B Moens J Davidson J A Lowden 《American journal of human genetics》1981,33(3):375-380
Chi-square analyses of new data as well as data previously reported by Myrianthopoulos have shown that grandparents of Tay-Sachs carriers die from proportionally the same causes as grandparents of noncarriers. It is unlikely that there is any advantage to being a Tay-Sachs carrier insofar as resistance to tuberculosis is concerned. Our results are further evidence to support Fraikor's claim that the high carrier frequency of the allele in Ashkenazi Jews is probably caused by a combination of founder effect, genetic drift, and differential immigration patterns. 相似文献
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