Severe acute respiratory syndrome (SARS)-CoV is a newly emerging virus that causes SARS with high mortality rate in infected people. To study the humoral responses against SARS-CoV, we evaluated nucleocapsid (N) and spike (S) proteins-specific antibodies in patients' sera by Western blotting and enzyme-linked immunosorbent assay (ELISA). Recombinant N and S proteins of SARS-CoV were purified from transformed E. coli. Serum specimens from 40 SARS-CoV-infected patients in the convalescent phase were analyzed by Western blotting using the purified antigens. Serial serum specimens from 12 RT-PCR-confirmed SARS patients were assayed by ELISA using the recombinant N protein as coated antigen. By Western blotting, 97.5% of the SARS patients were positive for N protein-specific antibodies whereas only 47.5% of the samples were positive for S protein-specific antibodies. Using N protein-based ELISA, 10 out of the 12 patients were positive for N protein-specific antibodies and 6 of them showed seroconversion at mean of 16 days after onset of fever. Immunoblotting was useful for detecting the humoral immune response after SARS-CoV infection. Antibodies against SARS-CoV N protein appear at the early stage of infection, therefore, N protein-based ELISA could serve as a simple, sensitive, and specific test for diagnosing SARS-CoV infection.
Lactobacillus plantarum 510, previously isolated from a koshu vineyard in Japan, was found to produce a bacteriocin-like inhibitory substance which was purified and characterized. Mass spectrometry analysis showed that the mass of this bacteriocin is 4,296.65 Da. A partial sequence, NH2- SSSLLNTAWRKFG, was obtained by N-terminal amino acid sequence analysis. A BLAST search revealed that this is a unique sequence; this peptide is thus a novel bacteriocin produced by Lactobacillus plantarum 510 and was termed plantaricin Y. Plantaricin Y shows strong inhibitory activity against Listeria monocytogenes BCRC 14845, but no activity against other pathogens tested. Bacteriocin activity decreased slightly after autoclaving (121 °C for 15 min), but was completely inactivated by protease K. Furthermore, trypsin-digested bacteriocin product fragments retained activity against L. monocytogenes BCRC 14845 and exhibited a different inhibitory spectrum.
Aim: To isolate and characterize bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria from the intestine of grey mullet. Methods and Results: Inhibitory activity against at least one or more indicator strains was observed in one Enterococcus thailandicus, one Enterococcus faecium and two Lactococcus garvieae strains. Enterococcus faecium B3-8 and Ent. thailandicus B3-22 showed the greatest inhibitory activities against Listeria monocytogenes ATCC 19111 and were therefore further characterized. The results suggested that the inhibitory substances from the two strains showed similar characteristics with respect to sensitivity to heat and proteolytic enzymes. BLIS from Ent. thailandicus B3-22 was characterized by a broader inhibitory spectrum than that from Ent. faecium B3-8. SDS-PAGE revealed that the molecular size of partially purified BLISs from Ent. faecium B3-8 and Ent. thailandicus B3-22 was c. 5 and 3 kDa, respectively. The molecular mass of purified bacteriocin from Ent. thailandicus B3-22 was further determined to be 6319 Da by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The results indicated that BLIS from Ent. thailandicus B3-22 can effectively inhibit the growth of all tested L. garvieae strains. Conclusions: The findings obtained in this study suggest the potential use of Ent. thailandicus B3-22 as a biocontrol agent against pathogenic L. garvieae in the aquaculture. Significance and Impact of the Study: This is the first report describing the characteristics of BLIS from Ent. thailandicus that showed potential for use as a biocontrol agent in the aquaculture.
Results from biochemical and functional characterizations of Nopp140 mutants defective in PKA phosphorylation sites suggest that PKA-dependent Nopp140 phosphorylation is important for its role in agp gene activation. Furthermore, maximal activation of the agp gene by PKA-phosphorylated Nopp140 depends on the presence of CREB and C/EBP. The participation of CREB in the activation is, however, independent of its PKA-mediated phosphorylation. In summary, we demonstrate the existence of a novel Nopp140-mediated PKA signaling pathway that leads to the activation of agp, one of the major acute phase response genes.
Nampt/visfatin acts in both intracellular and extracellular compartments to regulate multiple biological roles, including NAD metabolism, cancer, inflammation, and senescence. However, its function in chronic inflammation and carcinogenesis in hepatocellular carcinoma (HCC) has not been well-defined. Here we use Huh-7 hepatoma cells as a model to determine how Nampt/visfatin affects cellular survival under oxidative stress. We found that the transition of Nampt/visfatin from intracellular into extracellular form was induced by H2O2 treatment in 293T cells and confirmed that this phenomenon was not due to cell death but through the secretion of Nampt/visfatin. In addition, Nampt/visfatin suppressed cell viability in oxidative treatment in Huh-7 cells and acted on the inhibition of hepatoma cell growth. Oxidative stress also reduced the Nampt-mediated activation of NF-κB gene expression. In this study, we identify a novel feature of Nampt/visfatin which functions as an adipokine that can be secreted upon cellular stress. Our results provide an example to understand how adipokine interacts with chemotherapeutic treatment by oxidative stress in HCC.
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