严重急性呼吸综合征(SARS)冠状病毒刺突蛋白基因片段的表达及其初步应用

SARS virus spike gene fra gment was expressed by Ecoli expr ession systemThe fragment enclose s major neutralization epitope of the virusThe expressed protein wa s purified and an ELISA method was set upBy using the recombinant,tw elve patients' sera were detected The recombinant SARS coronavirus s pike protein offers an efficient wa y for serological diagnosis and is useful for epidemiological survey and vaccin e development     

The C-terminal portion of the nucleocapsid protein demonstrates SARS-CoV antigenicity

In order to develop clinical diagnostic tools for rapid detection of SARS-CoV (severe acute respiratory syndrome-associated coronavirus) and to identify candidate proteins for vaccine development, the C-terminal portion of the nucleocapsid (NC) gene was amplified using RT-PCR from the SARS-CoV genome, cloned into a yeast expression vector (pEGH), and expressed as a glutathione S-transferase (GST) and Hisx6 double-tagged fusion protein under the control of an inducible promoter. Western analysis on the purified protein confirmed the expression and purification of the NC fusion proteins from yeast. To determine its antigenicity, the fusion protein was challenged with serum samples from SARS patients and normal controls. The NC fusion protein demonstrated high antigenicity with high specificity, and therefore, it should have great potential in designing clinical diagnostic tools and provide useful information for vaccine development.     

The epitope study on the SARS-CoV nucleocapsid protein

The nucleocapsid protein (N protein) has been found to be an antigenic protein in a number of coronaviruses. Whether the N protein in severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is antigenic remains to be elucidated. Using Western blot and Enzyme-linked Immunosorbent Assay (ELISA), the recombinant N proteins and the synthesized peptides derived from the N protein were screened in sera from SARS patients. All patient sera in this study displayed strong positive immunoreactivities against the recombinant N proteins, whereas normal sera gave negative immunoresponses to these proteins, indicating that the N protein of SARS-CoV is an antigenic protein. Furthermore, the epitope sites in the N protein were determined by competition experiments, in which the recombinant proteins or the synthesized peptides competed against the SARS-CoV proteins to bind to the antibodies raised in SARS sera. One epitope site located at the C-terminus was confirmed as the most antigenic region in this prot     

严重急性呼吸综合征(SARS)冠状病毒抗体的检测及其临床意义

To investigate the k inetics of antibody to SARS coronavirus in SARS patients and its clinical implication,ELISA was used to dete ct antibody to SARS coronavirus(SA RS CoV),RT-PCR was used to detect the SARS CoV RNA and,besides,the C D+4 and CD+8 T cells in peripheral blood of SARS patients and healthy controls were assayed by flowcytom etryThe results showed that SARS CoV IgM were first detected from da y 7 to day 47 after SARS onset,wit h average at day 193±101SARS Co V IgG were first detected from day 4 to day 47 after SARS onset,with average at day 207±101,and the p roduction of SARS CoV IgG was corr elated with CD+4 T cell number(P<005),but had no relationship with SARS CoV RNAMost SARS patients pr oduced SARS CoV antibody,IgM produ ced almost at the same time wit h IgGSARS CoV IgG is a protective antibody against SARS CoV and the titer of IgG may be used as an ind ex indicating the specific immunit y production in SARS patients     

Indirect Enzyme-Linked Immunosorbent Assay Based on the Nucleocapsid Protein of SARS-like Coronavlruses

The nucleocapsid protein （N） is a major structural protein of coronaviruses. The N protein of bat SARS-like coronavirus （SL-CoV） has a high similarity with that of SARS-CoV. In this study, the SL-CoV N protein was expressed in Escherichia coli, purified and used as antigen. An Indirect Enzyme-Linked Immunosorbent Assay （indirect ELISA） was developed for detection of SARS- or SL-CoV infections in bat populations. The detection of 573 bat sera with this indirect ELISA demonstrated that SL-CoVs consistently circulate in Rhinilophus species, further supporting the proposal that bats are natural reservoirs of SL-CoVs. This method uses 1-2 μl of serum sample and can be used for preliminary screening of infections by SARS- or SL-CoV with a small amount of serum sample.     

DNA vaccine of SARS-Cov S gene induces antibody response in mice

The spike (S) protein, a main surface antigen of SARS-coronavirus (SARS-CoV), is one of themost important antigen candidates for vaccine design. In the present study, three fragments of the truncated S protein were expressed in E. coli, and analyzed with pooled sera of convalescence phase of SARS patients. The full length S gene DNA vaccine was constructed and used to immunize BALB/c mice. The mouse serum IgG antibody against SARS-CoV was measured by ELISA with E. coli expressed truncated S protein or SARS-CoV lysate as diagnostic antigen. The results showed that all the three fragments of S protein expressed by E. coli was able to react with sera of SARS patients and the S gene DNA candidate vaccine could induce the production of specific IgG antibody against SARS-CoV efficiently in mice with seroconversion ratio of 75% after 3 times of immunization. These findings lay some foundations for further understanding the immunology of SARS-CoV and developing SARS vaccines.     

Expression, purification and sublocalization of SARS-CoV nucleocapsid protein in insect cells

The causative agent of severe acute respiratory syndrome (SARS) is a previously unidentified coronavirus, SARS-CoV. The nucleocapsid (N) protein of SARS-CoV is a major viral protein recognized by acute and early convalescent sera from SARS patients. To facilitate the studies on the function and structure of the N protein, this report describe the expression and purification of recombinant SARS-CoV N protein using the baculovirus     

Sequence analysis and structural prediction of the severe acute respiratory syndrome coronavirus nsp5

The non-structural proteins (nsp or replicase proteins) of coronaviruses are relatively conserved and can be effective targets for drugs. Few studies have been conducted into the function of the severe acute respiratory syndrome coronavirus (SARS-CoV) nsp5. In this study, bioinformatics methods were employed to predict the secondary structure and construct 3-D models of the SARS-CoV GD strain nsp5. Sequencing and sequential comparison was performed to analyze the mutation trend of the polymerase nsp5 gene during the epidemic process using a nucleotide-nucleotide basic local alignment search tool (BLASTN) and a protein-protein basic local alignment search tool (BLASTP). The results indicated that the nsp5 gene was steady during the epidemic process and the protein was homologous with other coronavirus nsp5 proteins. The protein encoded by the nsp5 gene was expressed in COS-7 cells and analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This study provided the foundation for further exploration of the protein‘s biological function, and contributed to the search for anti-SARS-CoV drugs.     

H9N2亚型禽流感病毒非结构蛋白（NS1）基因的克隆与表达

The nostructural protein (NS1) encoded by gene 8 of the Influenza virus is present in cells infected with Influenza virus. In this study, NS1 protein gene of the Chicken influenza virus A/chicken/Beijing/2/97 (H9N2) strain was amplified by PCR. The fragment contains EcoR Ⅰ and Xho Ⅰ restriction enzyme sites at the ends. The amplified product was cloned into the expression vector pET-30(c). Recombinant plasmid pET/NS 1 was transformed into E.coli BL21 (DE3) competent cells and induced with 0.4 mmol/L IPTG the target protein was produced, the molecular weight of the expressed protein was 30 kDa as expected. Western-blot test indicated that the expressed protein can react with the NS 1 monoclonal antibody of the influenza virus. This study laid an important foundation for H9N2 subtype avian influenza surveillance in China.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.