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Migration Activity (migration + activity)
Selected AbstractsReducing Irregular Migration from ChinaINTERNATIONAL MIGRATION, Issue 3 2003James K. Chin With the development of China's economy since 1979, a new type of Chinese migration has emerged, which is more diversified and quite distinct from previous migration patterns. Trafficking in human beings and other forms of irregular migration are one of the most pressing and complex human rights issues today, reaching across borders and affecting most of the countries in the world, with new and serious security implications. As part of the international irregular migration flows toward and into the European Union (EU), the Chinese, particularly from Fujian and Zhejiang provinces, have played a major role since the 1980s. To some extent, it could be said that China provides the largest number of East Asian irregular immigrants to Europe. Based on fieldwork conducted in southern China over the past seven years, this paper proposes to examine current Chinese irregular migration trends. It will further present the Government's response regarding the migratory modus operandi and policy implications with the aim of offering policy makers an empirical insight into the most active region of emigration in China. Because of the difficulty and sensitivity involved in collecting data on the topic, materials in this paper are mainly based on a content analysis of local Chinese newspapers and my interviews with various people involved in irregular migration activities, such as "snakeheads", illegal migrants and their family members, and police, local, and government officials at different levels. [source] GDF-5/7 and bFGF activate integrin ,2-mediated cellular migration in rabbit ligament fibroblastsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2010Hirokazu Date Abstract Cellular activities responding to growth factors are important in ligament healing. The anterior cruciate ligament (ACL) has poor healing potential compared to the medial collateral ligament (MCL). To assess the differences, we investigated the proliferation, migration, adhesion, and matrix synthesis responding to growth factors in rabbit ACL and MCL fibroblasts. ACL cell proliferation to basic fibroblast growth factor (bFGF), bone morphogenetic protein-2, growth and differentiation factor (GDF)-5, and GDF-7 treatment was similar to that of MCL cells. GDF-5 enhanced Col1a1 expression in ACL and MCL fibroblasts up to 4.7- and 17-fold levels of control, respectively. MCL fibroblasts showed stronger migration activities in response to bFGF and GDF-5 than ACL cells. GDF-5/7 and bFGF also changed the stress fiber formation and cellular adhesion by modulating the distribution of integrin ,2. Functional blocking analyses using anti-integrin ,2 antibodies revealed that cellular migration responding to growth factors depended on the integrin ,2-mediated adhesion on type I collagen. The expression of integrin ,2 was also increased by growth factors in both cells. Our results demonstrate that GDF-5/7 and bFGF stimulate cellular migration by modulating integrin ,2 expression and integrin ,2-dependent adhesion, especially in MCL fibroblasts. These findings suggest that the different healing potential between ACL and MCL may be caused by different cellular behavior in the integrin ,2-mediated cellular migration in response to growth factors. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:225,231, 2010 [source] The archaeal Hjm helicase has recQ-like functions, and may be involved in repair of stalled replication forkGENES TO CELLS, Issue 2 2006Ryosuke Fujikane The archaeal Hjm is a structure-specific DNA helicase, which was originally identified in the hyperthermophilic archaeon, Pyrococcus furiosus, by in vitro screening for Holliday junction migration activity. Further biochemical analyses of the Hjm protein from P. furiosus showed that this protein preferably binds to fork-related Y-structured DNAs and unwinds their double-stranded regions in vitro, just like the E. coli RecQ protein. Furthermore, genetic analyses showed that Hjm produced in E. coli cells partially complemented the defect of functions of RecQ in a recQ mutant E. coli strain. These results suggest that Hjm may be a functional counterpart of RecQ in Archaea, in which it is necessary for the maintenance of genome integrity, although the amino acid sequences are not conserved. The functional interaction of Hjm with PCNA for its helicase activity further suggests that the Hjm works at stalled replication forks, as a member of the reconstituted replisomes to restart replication. [source] Uncoupling of the ATPase activity from the branch migration activity of RuvAB protein complexes containing both wild-type and ATPase-defective RuvB proteinsGENES TO CELLS, Issue 9 2003Takashi Hishida Background:,Escherichia coli RuvAB promotes branch migration of Holliday junctions during recombination repair and homologous recombination. RuvB forms a hexameric ring through which duplex DNA passes and is translocated in an ATP-dependent manner. ATPase-deficient RuvB mutant K68A has a mutation in the Walker A motif and exerts a dominant-negative effect on in vivo repair of UV-induced DNA damage. In this study, we examined RuvAB-dependent branch migration in the presence of a mutant RuvB, K68A. Results:, Mixing K68A with wild-type RuvB resulted in the formation of heterohexamers that showed unique properties of DNA binding, ATPase, and branch migration activities different from those of either wild-type or mutant homohexamers. RuvB heterohexamers inhibited branch migration and caused Holliday junctions to accumulate during RecA-mediated strand exchange. In the presence of RuvA, RuvB heterohexamers had Holliday junction-dependent ATPase activity, but did not promote branch migration. Conclusions:, These results suggest that functional cooperation among the subunits in the hexamers is required for branch migration, but inclusion of inactive subunits is tolerated for ATP hydrolysis. Therefore, we propose that an essential ATP hydrolysis-dependent functional cooperation is induced in RuvB hexamer subunits during RuvAB-mediated branch migration. [source] Promigratory Activity of Oxytocin on Umbilical Cord Blood-Derived Mesenchymal Stem CellsARTIFICIAL ORGANS, Issue 6 2010Yong Sook Kim Abstract Recent studies show that oxytocin has various effects on cellular behaviors. Oxytocin is reported to stimulate cardiomyogenesis of embryonic stem cells and endothelial cell proliferation. Mesenchymal stem cells (MSCs) are widely used for cardiac repair, and we elucidated the effect of oxytocin on umbilical cord derived-MSCs (UCB-MSCs). UCB-MSCs were pretreated with oxytocin (100 nM) and washed with saline prior to experiments. To evaluate their angiogenic potential and migration activity, tube formation assay and Boyden chamber assay were performed. For in vivo study, ischemia-reperfusion was induced in rats, and UCB-MSCs with or without oxytocin pretreatment were injected into the infarcted myocardium to evaluate the engraftment of injected cells. Histological and hemodynamic studies were performed. Oxytocin-treated UCB-MSCs showed a decrease in tube formation but a drastic increase in transwell migration activity. The transcription level of matrix metalloproteinase (MMP)-2 was increased in oxytocin-treated UCB-MSCs. Knock-down of MMP-2 by use of siRNA restored the tube formation, while reducing transmigration activity. In rats injected with oxytocin-treated UCB-MSCs, cardiac fibrosis and CD68 infiltration in the peri-infarct zone were reduced, whereas cell engraftment and connexin43 expression were greater than in rats injected with untreated UCB-MSCs. By contrast, angiogenesis did not differ significantly between the two groups. Cardiac contractility was higher in the group injected with oxytocin-treated UCB-MSCs than in the group injected with phosphate-buffered saline alone. Collectively, oxytocin is an effective priming reagent for stem cells for application to damaged heart tissue. [source] | ||||||||||