Universal Dynamic DNA Assembly-Programmed Surface Hybridization Effect for Single-Step, Reusable, and Amplified Electrochemical Nucleic Acid Biosensing

The traditional sensitive electrochemical biosensors are commonly confronted with the cumbersome interface operation and washing procedures and the inclusion of extra exogenous reagents, which impose the challenge on the detection simplicity, reliability, and reusability. Herein, we present the proof-of-principle of a unique biosensor architecture based on dynamic DNA assembly programmed surface hybridization, which confers the single-step, reusable, and enzyme-free amplified electrochemical nucleic acid analysis. To demonstrate the fabrication universality three dynamic DNA assembly strategies including DNA-fueled target recycling, catalytic hairpin DNA assembly, and hybridization chain reaction were flexibly harnessed to convey the homogeneous target recognition and amplification events into various DNA scaffolds for the autonomous proximity-based surface hybridization. The current biosensor architecture features generalizability, simplicity, low cost, high sensitivity, and specificity over the traditional nucleic acid-related amplified biosensors. The lowest detection limit of 50 aM toward target DNA could be achieved by hybridization chain reaction-programmed surface hybridization. The reliable working ability for both homogeneous solution and heterogeneous inteface facilitates the target analysis with a robust reliability and reproducibility, also making it to be readily extended for the integration with the kinds of detecting platforms. Thus, it may hold great potential for the biosensor fabrication served for the point-of-care applications in resource constrained regions

Molecular Typing and Epidemiology Profiles of Human Adenovirus Infection among Paediatric Patients with Severe Acute Respiratory Infection in China

<div><p>Background</p><p>Human adenoviruses (HAdVs) have been recognised as pathogens that cause a broad spectrum of diseases. The studies on HAdV infection among children with severe acute respiratory infection (SARI) are limited.</p><p>Objective</p><p>To investigate the prevalence, epidemiology, and genotype of HAdV among children with SARI in China.</p><p>Study Design</p><p>Nasopharyngeal aspirates (NPAs) or induced sputum (IS) was collected from hospitalised children with SARIs in Beijing (representing Northern China; n = 259) and Zhejiang Province (representing Eastern China; n = 293) from 2007 to 2010. The prevalence of HAdV was screened by polymerase chain reaction (PCR), followed by sequence typing of PCR fragments that targeted the second half of the hexon gene. In addition, co-infection with other human respiratory viruses, related epidemiological profiles and clinical presentations were investigated.</p><p>Results and Conclusions</p><p>In total, 76 (13.8%) of 552 SARI patients were positive for HAdV, and the infection rates of HAdV in Northern and Eastern China were 20.1% (n = 52) and 8.2% (n = 24), respectively. HAdV co-infection with other respiratory viruses was frequent (infection rates: Northern China, 90.4%; Eastern China, 70.8%). The peak seasons for HAdV-B infection was winter and spring. Additionally, members of multiple species (Human mastadenovirus B, C, D and E) were circulating among paediatric patients with SARI, of which HAdV-B (34/52; 65.4%) and HAdV-C (20/24, 83.3%) were the most predominant in Northern and Eastern China, respectively. These findings provide a benchmark for future epidemiology and prevention strategies for HAdV.</p></div

Genotype profiles and co-infection of HAdV.

<p>*, indicated the statistically difference of the HAdV infection rate between the Northern and Eastern China.</p><p>Genotype profiles and co-infection of HAdV.</p

Seasonal distribution of HAdV infection.

<p>*, also contain one HAdV-D (HAdV-37) and one HAdV-E (HAdV-4)</p><p>**, indicated the statistically difference of the HAdV infection rate among four seasons</p><p>Seasonal distribution of HAdV infection.</p

Phylogenetic analysis of HAdV based on the partial hexon gene.

<p>The phylogenetic tree was constructed by the neighbour-joining method, and bootstrap values were determined by 1000 replications in MEGA5.0. (Prefix-N: samples from Northern China; Prefix-E: samples from Eastern China; ■, sequences of the reference strains of HAdV-A cut from genomes found in GenBank; ●, sequences of reference strains of HAdV-B; ▼, sequences of reference strains of HAdV-C; Δ, sequences of reference strains of HAdV-D; ○, sequence of reference strain of HAdV-E; ◆, sequences of reference strains of HAdV-F.</p

Demographic data in this study.

<p>Demographic data in this study.</p

Age distribution of HAdV infection.

<p>*, also contain one HAdV-D (HAdV-37)</p><p>* *, also contain one HAdV-E (HAdV-4)</p><p>*** indicated the statistically difference of the HAdV infection rate among four age groups</p><p>Age distribution of HAdV infection.</p

Prevalence and Genetic Diversity Analysis of Human Coronavirus OC43 among Adult Patients with Acute Respiratory Infections in Beijing, 2012

<div><p>To determine the prevalence, epidemiology and genetic diversity of human coronavirus OC43 (HCoV-OC43) among adult patients with acute respiratory infections (ARI) in Beijing,five hundred and fifty-nine nasopharyngeal swab samples were collected from adult patients with ARI in Beijing. The prevalence of HCoV-OC43 infection among these patients was assessed using two different OneStep reverse transcription polymerase chain reaction (RT-PCR) assays. The epidemiological profiles of the patients with HCoV-OC43 infection were described. Partial S and N genes of HCoV-OC43 circulating strains were sequenced followed by phylogenetic analysis and amino acid alignment. Our results showed that the prevalence of HCoV-OC43 infection was 12.52% (95% CI: 9.78–15.26%), and the epidemic peak occurred in autumn. Fifty partial S and 40 partial N fragments were obtained from these patients. Phylogenetic analysis based on neighbour-joining method showed that at least three distinct clusters (A, B, C/D) of HCoV-OC43 strains were circulating among adult patients with ARI in Beijing. In addition, some novel unique clusters (UNT) of HCoV-OC43 were found in the S- and N-based phylogenetic trees. Furthermore, consensus amino acids substitutes for each cluster were also found after alignment of partial S or N sequence coding region in this study. In conclusion, we herein describe the prevalence of HCoV-OC43 among adult patients and provide substantial evidence for the genetic diversity of HCoV-OC43 circulating in Beijing.</p></div

Summary on consensus amino acid changes for each cluster among S coding region of HCoV-OC43.

<p>Summary on consensus amino acid changes for each cluster among S coding region of HCoV-OC43.</p