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BACKGROUND@#Zika virus (ZIKV) has emerged as a global pathogen causing significant public health concerns. China has reported several imported cases where ZIKV were carried by travelers who frequently travel between China and ZIKV-endemic regions. To fully characterize the ZIKV strains isolated from the cases reported in China and assess the risk of ZIKV transmission in China, comprehensive phylogenetic and genetic analyses were performed both on all ZIKV sequences of China and on a group of scientifically selected ZIKV sequences reported in some of the top interested destinations for Chinese travelers.@*METHODS@#ZIKV genomic sequences were retrieved from the National Center for Biotechnology Information database through stratified sampling. Recombination event detection, maximum likelihood (ML) phylogenetic analysis, molecular clock analysis, selection pressure analysis, and amino acid substitution analysis were used to reconstruct the epidemiology and molecular transmission of ZIKV.@*RESULTS@#The present study investigated 18 ZIKV sequences from China and 70 sequences from 16 selected countries. Recombination events rarely happens in all ZIKV Asian lineage. ZIKV genomes were generally undergone episodic positive selection (17 sites), and only one site was under pervasive positive selection. All ZIKV imported into China were Asian lineage and were assigned into two clusters: Venezuela-origin (cluster A) and Samoa-origin cluster (cluster B) with common ancestor from French Polynesia. The time of most recent common ancestors of Cluster A dated to approximately 2013/11 (95% highest posterior density [HPD] 2013/06, 2014/03) and cluster B dated to 2014/08 (95% HPD 2014/02, 2015/01). Cluster B is more variable than Cluster A in comparison with other clusters, but no varied site of biological significance was revealed. ZIKV strains in Southeast Asia countries are independent from strains in America epidemics.@*CONCLUSIONS@#The genetic evolution of ZIKV is conservative. There are two independent introductions of ZIKV into China and China is in danger of autochthonous transmission of ZIKV because of high-risk surrounding areas. Southeast Asia areas have high risk of originating the next large-scale epidemic ZIKV strains.
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Background@#Zika virus (ZIKV) has emerged as a global pathogen causing significant public health concerns. China has reported several imported cases where ZIKV were carried by travelers who frequently travel between China and ZIKV-endemic regions. To fully characterize the ZIKV strains isolated from the cases reported in China and assess the risk of ZIKV transmission in China, comprehensive phylogenetic and genetic analyses were performed both on all ZIKV sequences of China and on a group of scientifically selected ZIKV sequences reported in some of the top interested destinations for Chinese travelers.@*Methods@#ZIKV genomic sequences were retrieved from the National Center for Biotechnology Information database through stratified sampling. Recombination event detection, maximum likelihood (ML) phylogenetic analysis, molecular clock analysis, selection pressure analysis, and amino acid substitution analysis were used to reconstruct the epidemiology and molecular transmission of ZIKV.@*Results@#The present study investigated 18 ZIKV sequences from China and 70 sequences from 16 selected countries. Recombination events rarely happens in all ZIKV Asian lineage. ZIKV genomes were generally undergone episodic positive selection (17 sites), and only one site was under pervasive positive selection. All ZIKV imported into China were Asian lineage and were assigned into two clusters: Venezuela-origin (cluster A) and Samoa-origin cluster (cluster B) with common ancestor from French Polynesia. The time of most recent common ancestors of Cluster A dated to approximately 2013/11 (95% highest posterior density [HPD] 2013/06, 2014/03) and cluster B dated to 2014/08 (95% HPD 2014/02, 2015/01). Cluster B is more variable than Cluster A in comparison with other clusters, but no varied site of biological significance was revealed. ZIKV strains in Southeast Asia countries are independent from strains in America epidemics.@*Conclusions@#The genetic evolution of ZIKV is conservative. There are two independent introductions of ZIKV into China and China is in danger of autochthonous transmission of ZIKV because of high-risk surrounding areas. Southeast Asia areas have high risk of originating the next large-scale epidemic ZIKV strains.
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<p><b>BACKGROUND</b>Genetic association studies on populations of European origin have identified the DCDC2 gene as a susceptibility locus for developmental dyslexia. Here, we sought to investigate the association of DCDC2 polymorphisms with developmental dyslexia in children of Han Chinese origin.</p><p><b>METHODS</b>We undertook a case-control genetic association study on 76 dyslexic children and 79 non-dyslexic matched controls. We isolated DNA from oral mucosal cell samples and genotyped two DCDC2 coding-sequence single nucleotide polymorphisms, rs2274305 and rs6456593, in each sample using SNaPshot single nucleotide extension. We compared the allele and genotype frequencies between the groups using the χ(2) test and analyzed the relationship between dyslexia and the polymorphism at both loci using unconditional logistic regression. We also predicted haplotypes and compared their frequencies between the two groups.</p><p><b>RESULTS</b>The differences in the genotype distribution and the allelic genes of the two single nucleotide luci of the DCDC2 gene, rs2274305 and rs6456593, between the two dyslexic and non-dyslexic groups were statistically meaningless (P > 0.05). The differences in the haplotype distributions of the DCDC2 gene between the dyslexic and normal group were statistically meaningless (P > 0.05).</p><p><b>CONCLUSION</b>The DCDC2 gene may not be a susceptibility factor for developmental dyslexia among the Han Chinese. However, methodological issues may have prevented the detection of positive associations.</p>
Subject(s)
Child , Female , Humans , Male , Asian People , Dyslexia , Genetics , Genetic Predisposition to Disease , Genetics , Genotype , Haplotypes , Genetics , Microtubule-Associated Proteins , Genetics , Polymerase Chain Reaction , Polymorphism, Single Nucleotide , GeneticsABSTRACT
<p><b>BACKGROUND</b>Implantation of tissue-engineered scaffolds is one of the most promising therapeutic strategies for inducing nerve regenerations following spinal cord injuries. In this paper, we report a novel bioengineered hybrid scaffold comprised of three major extracellular matrix (ECM) proteins.</p><p><b>METHODS</b>ECM-scaffolds (ECM-S) were prepared by gelling fibrinogen, fibronectin and laminin using fresh rat plasma. Olfactory ensheathing cells (OECs) were isolated from fresh rat olfactory mucosa, purified under differential adhesion, and assessed by immunofluorescent staining. OECs were seeded onto ECM-S and cultured. The effects of the scaffolds on the seeded cells were detected using the immunofluorescent staining, Western blotting, scanning electron microscopy and transmission electron microscopy.</p><p><b>RESULTS</b>Tissue-engineered ECM-S could be easily molded into mat-like or cylindrical shapes and gelled by addition of fresh plasma. Observations by electron microscopy show that the ECM-S forms a stable three-dimensional porous network. Studies on the effects of the ECM-S on the biological behaviors of OECs in vitro indicate that the scaffold can promote OEC adhesion, proliferation and process extensions. Additionally, OECs seeded on the scaffold maintained the expression of nerve growth factor, matrix metalloproteinase-3 and matrix metalloproteinase-9.</p><p><b>CONCLUSION</b>We developed a biosynthetic hybrid gel which could be used as a scaffold for OEC transplantation; this gel can promote nerve regeneration following spinal cord injuries.</p>