Dayong Gu

Isolation, identification and genomic characterization of the Asian lineage Zika virus imported to China

1 Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China 2 Graduate School, Guangxi Medical University, Xining 530021, China 3 The Central Laboratory of Health Quarantine, Shenzhen Travel Healthcare Center, Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen 518033, China 4 Laboratory Animal Center, Academy of Military Medical Science, Beijing 100071, China 5 Graduate School, Anhui Medical University, Hefei 230032, China

Isolation and characterization of Zika virus imported to China using C6/36 mosquito cells

Here, we describe a cell culture-based procedure for isolating the infectious ZIKV (GenBank KU963796) from a human serum sample (ca. 50 μL) with an extremely low viral load (Ct value = 32).

Development of a smart dynamic surface chemistry for surface plasmon resonance-based sensors for the detection of DNA molecules

We report the design of a polyrotaxane surface for biosensor applications. The results show that a three-fold improvement in immobilization and hybridization efficiency has been achieved compared to PEG SAM. The results confirm that polyrotaxane is a very promising platform candidate for biosensor applications.

Surveillance of mosquito-borne infectious diseases in febrile travelers entering China via Shenzhen ports, China, 2013.

BACKGROUND About 100 million passengers enter China via Shenzhen ports every year and such huge populations increase the risk of various infectious diseases, particularly mosquito-borne diseases, entering China. This paper reports the testing and monitoring of mosquito-borne diseases in febrile travelers through Shenzhen ports in 2013. METHODS The blood samples of 619 febrile cases were collected and the serum of each sample was used for the specific gene amplification and IgM antibody detection of five typical mosquito-borne pathogens: Dengue virus (DENV), Japanese encephalitis virus (JEV), Chikungunya virus (CHIKV), yellow fever virus (YFV), and West Nile Virus (WNV). Additionally, malaria was diagnosed by rapid diagnostic tests (RDTs). RESULTS In total, 34 cases were detected of DENV infection (serotype I to IV), 17 cases of JEV infection, 2 cases of CHIKV infection, and 3 cases of malaria infection. No virus genes or IgM antibodies of YFV or WNV were detected in the samples. DENV, JEV and CHIKV cases were mainly from Southeast Asia, while malaria cases from Africa. CONCLUSIONS DENV, JEV and CHIKV were the primary pathogens imported via Shenzhen ports. International travelers with mosquito-borne infections would accelerate the spread of these diseases, thus reinforcing the need for surveillance of mosquito-borne infections at ports should become a high priority.

Multiplex biomarker analysis biosensor for detection of hepatitis B virus

In this paper, we report the development of a protein microarray-based biosensor for the detection of the hepatitis B virus (HBV) serological markers using surface plasmon resonance (SPR Printing buffer, protein immobilization time and concentration of the capture protein were optimized systematically to determine the best performance of the biosensor. Under optimal conditions, five hepatitis B markers in 20 μL human serum can be simultaneously detected within 30 minutes, whereas other methods such as ELISA and PCR can detect only one marker within four hours. This platform has been validated by analysis of 35 patients known to have hepatitis B, with 85% agreement between the test platform and analysis by commercial enzyme-linked immunosorbent assay (ELISA) kits. The results demonstrate that the protein microarray with SPR displayed a sensitivity of 0.1 ng mL(-1) for HBsAg. In addition to high sensitivity, it also shows excellent specificity, reproducibility and stability. This integrated protein microarray technique combined with SPR is a promising candidate for hepatitis B diagnosis with high-throughput.

Preparation and evaluation of a peptide nucleic acid gene chip system associated with surface plasmon resonance

The aim of this study was to construct a gene chip system based on a surface plasmon resonance technique, where peptide nucleic acid (PNA) oligomers are used as probes. Since the self-assembled monolayer (SAM) technology offers good control at the molecular level, we prepared 2D surface chemistry via SAM for probe attachments. PNA, which was designed according to the bioinformatics, was immobilized on the SAM-modified chip, and subsequently, relevant parameters of the experiment were ensured and optimized. Our results suggest that the ion strength and pH value of the buffer solution do not play significant roles in PNA or its complementary strand hybridization. The PNA probe binds to its complementary nucleic acid strand with a higher sensitivity and specificity compared to those of a traditional DNA probe. The PNA probe combined with surface plasmon resonance (SPR) technology has the benefits of being a label-free and in-real time monitor, as well as having improved hybridization and stability efficiency, which highlight the PNA gene chip detection system as a promising biosensor for clinical applications.

Development of SPR biosensor for simultaneous detection of multiplex respiratory viruses.

A surface plasmon resonance (SPR)-based biosensor was developed for specific detection of nine common respiratory virus, including influenza A and influenza B, H1N1, respiratory syncytial virus (RSV), parainfluenza virus 1-3 (PIV1, 2, 3), adenovirus, and severe acute respiratory syndrome coronavirus (SARS). The SPR biosensor was developed by immobilizing nine respiratory virus-specific oligonucleotides in an SPR chip. To increase the biosensor sensitivity, biotin was used to label the PCR primer and further amplify the signal by introducing streptavidin after hybridization. Throat swab specimens representing nine common respiratory viruses were tested by the innovative SPR-based biosensor to evaluate the sensitivity, specificity and reproducibility of this method. Results suggest that this biosensor has the potential to simultaneously identify common respiratory viruses.

Development of a replicon cell line-based high throughput antiviral assay for screening inhibitors of Zika virus

Abstract Zika virus (ZIKV) is an important emerging human pathogen associated with microcephaly, Guillain‐Barré syndrome and meningoencephalitis. Developing rapid and reliable HTS assay is important for ZIKV drug discovery. Here, we constructed a dicistronic ZIKV replicon (ZIKV‐Pac‐Rluc‐Rep) that contained the Renilla luciferase (Rluc) reporter gene separated from the puromycin N‐acetyl‐transferase (Pac) selectable marker by a short peptide cleavage site. A clonal replicon cell line stably expressing high level of ZIKV replicon was established by selection with puromycin. By optimizing cell number, compound concentration and incubation time, a robust replicon cell‐based HTS assay was developed with a calculated Z′ value of >0.5. The fully optimized assay was further validated using several known flavivirus replication inhibitors. Altogether, the replicon cell‐based HTS assay developed in this study will facilitate the discovery of antiviral compounds against ZIKV. HighlightsA novel dicistronic ZIKV replicon (ZIKV‐Pac‐Rluc‐Rep) was constructed.A clonal replicon cell line stably expressing high level of ZIKV replicon was established.A robust replicon cell‐based HTS assay was developed with a calculated Z′ value of >0.5.

Real-time monitoring of T-cell-secreted interferon-γ for the diagnosis of tuberculosis

ABSTRACT In this paper, we report the development of a label-free biosensor, based on surface plasmon resonance, for real-time monitoring of captured human CD4+T-cells, and their dynamic cytokine production upon specific antigen stimulation. Microarrays of CD4+T-cells, and interferon gamma (IFN-γ) specific antibody (Ab) spots were printed side by side onto the poly(OEGMA-co-HEMA) matrix. The placement of CD4+ T-cells near the anti IFN-γ Ab-coated spots ensured a high local concentration of secreted IFN-γ for detection. We have demonstrated that this approach enables the detection of tuberculosis (TB) infection in clinical samples, with an overall sensitivity of 85.5% and an overall specificity of 97.7%.

Differential expression of long non-coding RNAs in patients with tuberculosis infection

Tuberculosis (TB) remains a major worldwide health problem and has caused millions of deaths in the past few years. Current diagnostic methods, such as sputum smear microscopy and sputum culture, are time-consuming and cannot prevent the rapid spreading of TB during the diagnostic period. In this connection, detecting biomarkers specific to TB at molecular level in plasma of patients will provide a rapid means for diagnosis. In this study, we first evaluated the differential expression of the long non-coding RNAs (lncRNAs) in the plasma from patients with TB (TB positive), community acquired pneumonia (CAP) and healthy individuals (CG) using lncRNA microarray scanning. It was found that there were 2116 specific lncRNAs differentially expressed in the TB positive samples (1102 up-regulated and 1014 down-regulated), which accounted for 6.96% of total lncRNAs. Twelve differentially expressed lncRNAs discovered in microarray were subsequently validated by using real-time quantitative PCR (RT-qPCR). Two lncRNAs (ENST00000354432 and ENST00000427151) were further validated with more Tuberculosis samples. These results suggested the expression level of lncRNAs and the two validated lncRNAs in plasma could be the potential molecular biomarkers for the rapid diagnosis of Tuberculosis.