Two conserved histidines (His490 and His621) on the E2 glycoprotein of hepatitis C virus are critical for CD81-mediated cell entry.

Hepatitis C virus (HCV) entry is a sequential and multi-step process that includes receptor interactions followed by pH-dependent membrane fusion. Specific and conserved histidine residues on the viral envelope proteins are involved in most pH-induced virus entries. In the case of HCV, some conserved histidines on the E1 and E2 proteins have been investigated in HCV pseudotype particle (HCVpp) systems.

A survey of the 2014 dengue fever epidemic in Guangzhou, China.

In 2014, a serious dengue outbreak in Guangzhou occurred, consisting of 37 354 laboratory confirmed cases of infection. In this study, the clinical picture of dengue fever due to dengue virus (DENV) type 1 in Guangzhou was described. Clinical and laboratory data collected by studying 726 sera of suspected clinical cases from hospitals and 328 sera of healthy persons from two residence communities were analyzed during the outbreak, and 484 patients were diagnosed with an acute dengue infection.

[Screening and identification of dengue virus type 2-specific antigens].

Objective: To screen and identify dengue virus type 2 specific antigens and establish an enzyme-linked immunosorbent assay (ELISA) for detecting dengue virus type 2 antibody.

Methods: Using the bioinformatic software DNAstar and ANTHEPROT, we analyzed the hydrophilicity, flexibility, surface probability and antigenicity of dengue virus type 1-4, Japanese encephalitis virus, and Yellow fever virus M and E protein amino acid sequences, and also evaluated the influence of secondary structure. The specific epitopes of dengue virus type 2 were predicted according to the epitope location and amino acid sequence similarity, and the epitope conservation was assessed using the sequence information of different dengue virus type 2 strains in GenBank.

Simultaneous analysis of foodborne pathogenic bacteria by an oligonucleotide microarray assay.

A rapid and accurate method for simultaneous identification of foodborne infectious pathogens was developed based on oligonucleotide microarray technology. The proposed identification method is based on PCR amplification of the target region of the groEL genes with degenerate primers, followed by the PCR products hybridization with oligonucleotide probes specific for species. The groEL gene amplification products of seventeen species of pathogenic bacteria were hybridized to the oligonucleotide array.

[Study on the characteristics of Tsutsugamushi disease in the epidemic areas of south islands in China].

Objective: To study the increasing incidence and the characteristics of Tsutsugamushi disease in the areas of Nan Peng Lie islands, Nan Ao island, Wan Shan archipelago, Nao Zhou island and Lei Zhou peninsula, located in the southern part of China and to develop strategies for preventive measures.

Methods: Both epidemiological investigation, isolation and gene identification of Orientia tsutsugamushi, as well as pilot preventive measures were carried out.

Results: These islands belonged to the epidemic area of south subtropical zone of Tsutsugamushi disease.

Monoclonal antibody-based antigen capture enzyme-linked immunosorbent assay reveals high sensitivity of the nucleocapsid protein in acute-phase sera of severe acute respiratory syndrome patients.

Accurate and timely diagnosis of severe acute respiratory syndrome coronavirus (SARS-CoV) infection is a critical step in preventing another global outbreak. In this study, 829 serum specimens were collected from 643 patients initially reported to be infected with SARS-CoV. The sera were tested for the N protein of SARS-CoV by using an antigen capture enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibodies against the N protein of SARS-CoV and compared to 197 control serum samples from healthy donors and non-SARS febrile patients.

[An epidemiologic investigation on infection with severe acute respiratory syndrome coronavirus in wild animals traders in Guangzhou].

Objective: To investigate status of infection with severe acute respiratory syndrome coronovirus (SARS-CoV) in traders of wild animals wholesale markets in Guangzhou.

Methods: Serum antibody against SARS-CoV IgG was determined cross-sectionally and symptoms of respiratory infection were investigated retrospectively for part of traders of three wholesale markets for wild animals in Guangzhou.

Results: Overall rate of infection with SARS-CoV in 635 traders was 16.