Cytotoxic Responses and Apoptosis in Rat Kidney Epithelial Cells Exposed to Lead / 生物医学与环境科学（英文）

The toxic effects of lead on normal rat kidney epithelial cells (NRK cells) may occur via various pathways. However, the role of intrinsic mitochondrial pathway in Lead-induced apoptosis in NRK cells has not been investigated. The purpose of our study was to investigate cytotoxic responses and cell apoptosis mediated by lead in NRK cells. NRK cells were treated with different concentrations of Lead acetate for 12 h to determine the cytotoxicity of lead. Mitochondrial transmembrane potential was also analyzed using a fluorescence spectrophotometer. Moreover, the activities of caspase-3 and caspase-9 were detected in the presence of lead. Finally, the lead-induced cell apoptosis was evaluated by flow cytometry in the present of caspase inhibitors Z-VAD-FMK and Ac-LEHD-FMK, respectively. The results would contribute to clarify the role of Lead in proliferation and apoptosis of NRK cells, and help to understand the underlying mechanism responsible for lead-induced cell apoptosis.

Isolation, identification and full-length genome sequence analysis of encephalomyocarditis virus from local aardvarks / 病毒学报

Encephalomyocarditis virus (EMCV) is a natural epidemic zoonotic pathogen. However, no reports have been published regarding the isolation, identification and full-length genome of EMCV from a local aardvark population. In present study, an EMCV isolate HNXX13 was isolated from aardvarks named Huainan-pig in Henan Province. The systematic identification, full-length genome sequencing and molecular characteristic analysis of the isolate HNXX13 were conducted. The result showed that the isolate was spherical with a diameter of 24-30 nm, neither heat- nor acid-resistant, sensitive to trypsin, insensitive to chloroform, not protected by bivalent cationic, and the specific fluorescence was observed in the cytoplasm of BHK-21 cells infected with the isolate by using indirect fluorescence assay. The full-length genome of EMCV HNXX13 generated a 7 725bp sequence (GenBank: F771002), with 81.0%-99.9% nucleotide identity to reference strains from different animals, and 99.5% with a Chinese reference strain isolated earlier from a commercial pig herd. The phylogenetic tree based on the full-length genome and ORF sequences identified that all EMCV strains were divided into three groups G1, G2 and G3, and strain HNXX13 belonging to the G1 group with other Chinese reference strains. The result also identified that this EMCV infection could cause severe clinical signs in a local aardvark population, and enriches the molecular epidemiological data of EMCV in China. Regional differences exist in EMCV genome and transmission is limited within a certain area. However, the cross-infection and transmission of EMCV between aardvark and mice appears most likely. Mutations have occurred in some amino acids of EMCV strain HNXX13 during the transmission in local aardvark herd and these mutations might make the virus easier to infect the aardvark.

Enhancing mucosal immunity in mice by recombinant adenovirus expressing major epitopes of porcine circovirus-2 capsid protein delivered with cytosine-phosphate-guanosine oligodeoxynucleotides

A recombinant replication-defective adenovirus expressing the major epitopes of porcine circovirus-2 (PCV-2) capsid protein (rAd/Cap/518) was previously constructed and shown to induce mucosal immunity in mice following intranasal delivery. In the present study, immune responses induced by intranasal immunization with a combination of rAd/Cap/518 and cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) were evaluated in mice. The levels of PCV-2-specific IgG in serum and IgA in saliva, lung, and intestinal fluids were significantly higher in the group immunized with rAd/Cap/518 and CpG ODN than animals immunized with rAd/Cap/518 alone. The frequencies of IL-2-secreting CD4+ T cells and IFN-gamma-producing CD8+ T cells were significantly higher in the combined immunization group than mice immunized with rAd/Cap/518 alone. The frequencies of CD3+, CD3+CD4+CD8-, and CD3+CD4-CD8+ T cells in the combined immunization group were similar to that treated with CpG ODN alone, but significantly higher than mice that did not receive CpG ODN. PCV-2 load after challenge in the combined immunization group was significantly lower than that in the phosphate-buffered saline placebo group and approximately 7-fold lower in the group treated with CpG ODN alone. These results indicate that rAd/Cap/518 combined with CpG ODN can enhance systemic and local mucosal immunity in mice, and represent a promising synergetic mucosal vaccine against PCV-2.