Objective To identify the subcellular location of S AR S-CoV N protein in mammalian cells. Methods The gene fraction of SARS-CoV was cloned into the PGEFP-C1 plasmid to construct expression vecto r PGEFP-C1/N. The subcellular location of N in A549 and VeroE6 cells was observ ed under fluorescence microscope with the aid of transient transfection techniqu e. The expression of the fusion protein (GFP-N) was detected by Western blot. Results The PGEFP-C1/N was constructed. N protein was localiz ed in the cytoplasm of transfected cells and detected by Western blot. C onclusion N protein was localized in the cytoplasm of mammalian cells.

Objective To construct an expression vector pGEX-2T/N, and to express the fusion protein consisting of N protein of SARS-CoV in E. coli.Methods The N region gene of SARS-CoV was obtained by RT-PCR. The expression vector PGEX-2T/N was constructed by DNA recombination. The recombinant plasmid was transformed into E. coli BL21(DE3). The expression of the fusion protein was determined by Western blot with anti-SARS-CoV antibody positive blood sera. Results The N region gene of SARS-CoV was obtained. The fusion protein GST-N was soluble. Western blot analysis showed that the reaction of GST-N to anti-SARS-CoV sera was positive. Conclusion The pGEX-2T/N has been constructed and expressed in the form of fusion protein GST-N successfully, and the result lays the foundation for further study of SARS-CoV N protein.

Objective To prepare and characterize the polyclonal antibody against N protein of SARS-CoV. Methods The polyclonal antibody against SARS-CoV N was obtained from immunized rabbit with purified GST-N. The titer of the antibody was determined by indirect ELISA, and the specificity by Western blot and immunochemical staining. Results The rabbit′s antibody against SARS-CoV N was prepared successfully. The titer of antiserum against SARS-CoV N was about 1.2?10~ -5 . Western blot and immunochemical staining analysis showed that the polyclonal antibody could bind to the expressed fusion protein specifically. Conclusion The rabbit′s antibody against SARS-CoV N has been prepared successfully, and it can be a useful reagent for clinical diagnosis and further research.

To evaluate the charasteristics and risk factors of hospital infections in patients with contagious diseases, 489 patients with contagious diseases were analyzed. Among 18 patients who contracted hospital infections, 17 were suffering from chronic hepatitis. 77 78% of them were over 40 years old. Infection of ascitic fluid, lower respiratory tract, and blood stream comprised 77 78% of the infections. Most of the doctors used antibiotics empirically. The survey showed that patients over 40 years old in an infectious diseases hospital were vulnerable to hospital infections. Hospital infection often occurred in the abdomen, lower respiratory tract, and blood stream. Abdominal paracentesis liver puncture biopsy, and lumbar puncture were the first three exogenous risk factors.