Construction of a recombinant Lactobacillus acidophilus expressing high levels of Helicobacter pylori adhesin Hp0410 / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a recombinant Lactobacillus acidophilus that expresses high levels of Helicobacter pylori (Hp) adhesin Hp0410.</p><p><b>METHODS</b>The gene fragment encoding Hp0410 was amplified by PCR from the DNA of H. pylori NCTC11639 strain and cloned into the shuttle plasmid pMG36e to construct pMG36e-Hp0410, which was transformed into Lactobacillus acidophilus by electroporation. The target protein was confirmed with SDS-PAGE and silver nitrate staining and analyzed by Western blotting. The stability of the recombinant plasmid was assessed by drawing the growth curve of the recombinant Lactobacillus acidophilus.</p><p><b>RESULTS</b>A 750-bp fragment was inserted into the pMG36e plasmid and transformed into Lactobacillus lactis. The transformed bacterium expressed the target protein with a relative molecular mass of about 34 kD. Western blotting confirmed that the expressed proteins could be recognized by the serum of patients with Hp infection. The recombinant plasmid pMG36e-Hp0410 exhibited good stability in the presence or absence of erythromycin.</p><p><b>CONCLUSIONS</b>The recombinant Lactobacillus acidophilus with high constitutive expression of Hp0410 has been constructed successfully.</p>

Effects of Newcastle disease virus on the expression of survivin and cell cycle in human tongue squamous carcinoma TSCCa cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of Newcastle disease virus (NDV) infection on the expression of survivin and cell cycle in human tongue squamous carcinoma TSCCa cells.</p><p><b>METHODS</b>The proliferation of TSCCa cells infected with NDV in vitro was evaluated by means of MTT assay, and survivin expression in the infected cells was detected using RT-PCR and Western blotting. Flow cytometry was performed to assess the changes in the cell apoptosis, cell cycle and cell proliferation index (PI) of the cells.</p><p><b>RESULTS</b>NDV infection resulted in decreased survivin expression and increased apoptosis of TSCCa cells, with reduced cell percentage in G2/M and S phases and lowered PI of the cells, showing significant differences from those of the negative control cells (P<0.05).</p><p><b>CONCLUSION</b>NDV infection can inhibit survivin expression, affect the cell cycle of TSCCa cells and induce their apoptosis.</p>

Variability analysis of S2 gene of SARS-CoV / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the sequence of S2 gene of SARS-associated coronavirus (SARS-CoV) GD322 and analyze the phyletic evolution of S2 gene.</p><p><b>METHOD</b>S2 gene fragment was amplified from SARS-CoV GD322 genome with RT-PCR and ligated to pGEM-T vector for sequence analysis after transformation of the plasmid into E. coli DH5a. The variability of S2 genes and S2 proteins from 12 strains isolated in the early, intermediate and advanced stages of the SARS outbreak were analyzed and the phylogenetic tree was constructed with Lasergene, Clustal X, DNAman and Treeview. T cell antigen epitopes of S2 protein were predicted on the basis of Internet database.</p><p><b>RESULT</b>With the epidemic spread of SARS-CoV, the S2 genes of the virus tended to become stable. Homology of S2 genes of SARS-CoV isolated in advanced stage of the outbreak reached 99.9%. Prediction of T cell antigen epitope showed that mutation at the 57th amino acid effected T cell antigen epitope.</p><p><b>CONCLUSION</b>S2 gene of GD322 SARS-CoV is relatively stable during the epidemic spread of the virus, and mutation at the 57th amino acids of S2 protein may affect the T cell antigen epitope.</p>

Advanced in Origin of SARS Coronavirus / 微生物学通报

SARS coronavims is an emerging virus. A lot of animals could be infected by SARS-CoV and Himalayan palm civets, as one of important hosts, is an ideal animal model. Viral genetic factors have been implicated in the emergence of SARS-CoV, with the suggestion that this virus is a recombinant between mammalian and avian coronaviruses. However, the recombination is unlikely to explain the appearance of SARS in humans.