[Prokaryotic expression and identification of S-dsRNA gene from Cryptosporidium parvum virus].

OBJECTIVE: To clone and express S-dsRNA gene of Cryptosporidium parvum virus, and investigate the reactogenicity of the recombinant. METHODS: Total RNA was extracted from Cryptosporidium parvum and S-dsRNA gene was amplified by RT-PCR. The PCR product was cloned into pET-28a(+) expression vector. The recombinant plasmid pET-28a(+)-S was transformed into E. coli BL21 (DE3) and induced with IPTG. The expression situation of recombinant protein was analyzed by SDS-PAGE. Its reactogenicity was examined by Western blotting analysis. RESULTS: pET-28a (+)-S was identified by PCR and double endonuclease digestion. SDS-PAGE result showed that the recombinant protein (M, 37,000) was expressed in the form of inclusion body. High level expression of recombinant protein was found at 1 mmol/L IPTG condition after incubation at 37 degrees C for 4 h and reached up to 72.6% of the total protein. The protein was recognized by the antisera from mice immunized with antigens from Cryptosporidium parvum oocysts. CONCLUSION: The S-dsRNA gene of Cryptosporidium parvum virus has been expressed with adequate reactogenicity.

Rho-associated protein kinase inhibitor, Y-27632, significantly enhances cell adhesion and induces a delay in G1 to S phase transition in rabbit corneal endothelial cells.

Human corneal endothelial cells are a non-proliferative cell type. As a result of the increase in corneal endothelium disease, increasing numbers of studies have been conducted in order to promote corneal endothelial cell proliferation. The aim of the present study was to investigate the proliferative effects of Rho-associated protein kinase inhibitor, Y-27632, on rabbit corneal endothelial cells (rCECs). Y-27632 (1, 10 or 30 µM) was added at two different time points to two groups of rCECs. The first group received Y-27632 when rCECs were initially plated, and the second following 72 h of cell growth. Cell morphology and cell adhesion ratios were subsequently observed using light microscopy. A cell counting kit was used to measure the number of viable cells that adhered to culture plates. Cell cycle transitions and levels of Annexin V-positive apoptotic cells were detected using flow cytometry. Cells treated with 1 µM Y-27632 and 10 µM Y-27632 retained their cell shape. At a concentration of 30 µM Y-27632, the cell shape became irregular. Cell adhesion ratios, in 1 µM Y-27632 (36.84%), 10 µM Y-27632 (84.21%) and 30 µM Y-27632 (84.21%) were higher than the adhesion ratio in the control group (P<0.01). The optical densities of rCECs treated with 10 µM or 30 µM Y-27632 following 72 h of cell growth was less than that of the control cells (P<0.01), but higher than that of cells which received Y-27632 at the time of plating (P<0.01). Flow cytometry results also demonstrated that there was a delay in G1 to S phase cell cycle progression in rCECs following administration of 10 µM Y-27632 (P<0.01). Cell apoptosis was inhibited when 10 µM Y-27632 was added, at the time of cell plating, as well as when added following 72 h of cell growth (P<0.01). At a concentration of 10 µM Y-27632, there was an improvement in cell adhesion and an inhibition of the cell cycle in rabbit corneal endothelial cells. In conclusion, Y-27632 has different effects on rCECs when administered at varying concentrations and at particular stages of cell growth.

Feasibility and safety of porcine Descemet's membrane as a carrier for generating tissue-engineered corneal endothelium.

The aim of this study was to evaluate the feasibility and safety of porcine Descemet's membrane (DM) as a carrier for the generation of tissue-engineered corneal endothelium by analyzing porcine endogenous retroviruses (PERVs) and the α-gal epitope. The morphology of porcine and human DM was observed by hematoxylin and eosin staining and scanning electron microscopy. Immunohistochemical staining was used to investigate the location of α-gal epitopes on porcine DM used for xenotransplantation. The porcine DM was treated with ethylene glycol diglycidyl ether (EDGE) for 2 weeks, and then the PERV gene sequences in porcine DM and DM-EDGE were detected by polymerase chain reaction (PCR) and real-time PCR, respectively. The porcine DM had tight basement membrane morphology, which was similar to human DM in terms of thickness. No positive immunohistochemical staining of the α-gal epitope was detected in porcine DM. PERV expression of pol, gag, env-A and env-B was noted in porcine DM, but in DM-EDGE it was completely degraded. Based on structural, immunological and etiological studies, porcine DM may be an ideal and viable carrier for the generation of tissue-engineered corneal endothelium.