Current understanding of genomic DNA of porcine circovirus type 2.

Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases in swine and is also described as the modulator of host immunity that exacerbates the clinical outcome of many bacterial and viral infections. To date, it has caused increasingly larger losses in the pig industry worldwide. The genomic DNA of PCV2 is predicted to contain 11 open reading frames (ORFs) and at least seven potential ORFs-encoding proteins larger than 5 kDa. Currently, however, only five virally encoded proteins (Rep, Rep', Cap, ORF3, and ORF4 protein) have been identified in PCV2 replication. In the present review, we strive to discuss the current understanding of the genomic DNA of PCV2 with the purpose of providing insight into the scientific basis of the pathogenesis of PCV2 and the prevention of its infection.

Identification of two internal signal peptide sequences: critical for classical swine fever virus non-structural protein 2 to trans-localize to the endoplasmic reticulum.

BACKGROUND: The membrane topology and molecular mechanisms for endoplasmic reticulum (ER) localization of classical swine fever virus (CSFV) non-structural 2 (NS2) protien is unclear. We attempted to elucidate the subcellular localization, and the molecular mechanisms responsible for the localization of this protein in our study. The NS2 gene was amplified by reverse transcription polymerase chain reaction, with the transmembrane region and hydrophilicity of the NS2 protein was predicted by bioinformatics analysis. Twelve cDNAs of the NS2 gene were amplified by the PCR deletion method and cloned into a eukaryotic expression vector, which was transfected into a swine umbilical vein endothelial cell line (SUVEC). Subcellular localization of the NS2 protein was characterized by confocal microscopy, and western blots were carried out to analyze protein expression. RESULTS: Our results showed that the -NH2 terminal of the CSFV NS2 protein was highly hydrophobic and the protein localized in the ER. At least four transmembrane regions and two internal signal peptide sequences (amino acids103-138 and 220-262) were identified and thought to be critical for its trans-localization to the ER. CONCLUSIONS: This is the first study to identify the internal signal peptide sequences of the CSFV NS2 protein and its subcellular localization, providing the foundation for further exploration of this protein's function of this protein and its role in CSFV pathogenesis.

[Analysis of rare earth elements in pu'er tea of Yunnan by ICP-AES].

The 150 samples of pu'er tea collected from the main producing area of Yunnan were detected by ICP-AES method, to investigate the current safety status of pu'er tea rare earth elements. The rare earth elements contents were found to be in the range 0.26-4.07 mg x kg(-1) in all detected samples, with the 43.0% samples exceeding the maximum levels of contaminants of 2 mg x kg(-1) set by GB 2762-2005 "Maximum levels of contaminants in foods". There was a significant difference between ripened tea rare earth elements and raw tea's from the same sources, which affected some ripened tea quality at last. There was a significant difference among the rare earth elements contents of the pu'er tea main producing areas, and the condition of pu'er tea quality and safety controlling was not optimistic at individual producing areas.

Cytopathic effect of classical swine fever virus NS3 protein on PK-15 cells.

In order to further research the relationship between classical swine fever virus' (CSFV) NS3 protein and the cytopathic effect (CPE) in cells infected with the CSFV, and to reveal the effect of protein NS3 on the host cells, the NS3 of CSFV Shimen strain amplified by RT-PCR was subcloned into the pEGFP-C1, named pEGFP-C1-NS3. The insert position, the size and the reading frame were correct for restriction enzyme digestion and sequence analysis. The pEGFP-C1-NS3 and pEGFP-C1 were transfected into PK-15 cells by liposome, and positive cell clones were gained by G418. The NS3-EGFP fusion protein expressed in pEGFP-C1-NS3 cells was observed by inverted fluorescence microscopy and identified by Western blot. The CPE appeared in positive pEGFP-C1-NS3 cells 72 h after passaging, apoptosis detection was also performed on positive pEGFP-C1-NS3 cells and pEGFP-C1 cells 72 h after passaging by TUNEL assay. The apoptosis rates in the positive pEGFP-C1-NS3 and pEGFP-C1 cells were 43.4 and 13.1%, respectively (p < 0.05). The results suggest that the CPE in positive pEGFP-C1-NS3 cells was induced by apoptosis and there is a relationship between the expression of NS3 and apoptosis.