Biomedical subjects

Yue-Jun Wang

Publications and source records attributed to Yue-Jun Wang.

7 recordsLinked to original sources

PubMed2006

A polypeptide from Chlamys farreri abolishes UV-induced apoptosis in murine thymocytes in vitro.

Previously we reported that a polypeptide from Chlamys farreri (PCF) was a potent photoprotective agent against ultraviolet (UV) irradiation in vitro. To understand the mechanism by which PCF protects cells from irradiation, we studied anti-apoptotic effects of PCF against UV irradiation on the murine thymocytes in vitro. MTT and flow cytometric analysis assays showed that 2h pretreatment with PCF completely abolished UV induced cell death. TEM examination showed that PCF fully protected the ultrastructure of thymocytes exposed to UV irradiation. Lipid peroxidation and intracellular reactive oxygen species assays indicated that PCF efficiently blocked production of reactive oxygen intermediates induced by UV irradiation. Further, PCF protected UV-irradiated thymocytes from losing mitochondrial transmembrane potential and DNA fragmentation. Based on these observations we propose that PCF is a potent anti-apoptotic factor, which protects cells from irradiation at multiple steps.

Animals↗

PubMed2005

Polypeptide from Chlamys farreri inhibits murine thymocytes apoptosis and modulates UVB induced signaling pathway activation.

Polypeptide from Chlamys farreri (PCF) has been identified as a potent antioxidant and photoprotective agent. In this study, we investigated whether PCF could inhibit apoptosis of murine thymocytes induced by ultraviolet B (UVB) and modulate UVB induced the mitogen-activated protein kinases (MAPKs) cascade in vitro. Our results show that PCF inhibit UVB-induced apoptotic cell death in murine thymocytes. We also found that PCF potently stimulated the phosphorylation of ERKs, which is involved in the cell survival-signaling cascade. Furthermore, the specific inhibition of the ERKs pathways by PD98059 reduced the cytoprotective effect of PCF. On the other hand, the JNKs and p38 inhibitor SP600125 and SB203580 additively enhanced the cytoprotective effect of PCF. We concluded that the activation of JNKs and p38 kinase played an important role in UVB-induced apoptosis, and PCF likely exerted its cytoprotective effect in thymocytes through ERKs activation. These suggested that part of the antiapoptotic effect of PCF might be mediated by its ability to modulate the MAPKs cascade.

Analysis of Variance↗

PubMed2005

[Purification and characterization of a lysozyme from a marine microorganism].

A novel lysozyme was purified from a marine microorganism and its major characteristics were studied. Cell-free supernatant was prepared by centrifugation of culture broth, ultrafiltration using a hollow fiber (molecular weight cut off, 50kD) and concentration using a hollow fiber (molecular weight cut off, 10kD). The crude lysozyme was purified 34.7 fold to electrophoretic homogeneity with a recovery of 24.1% by CM-Sepharose FF cationic-exchange and Sephadex G-100 gel chromatography. The relative molecular weight of this lysozyme was determined as about 39 kD. The optimum pH and temperature towards Micrococcus lysodleikticus were pH 8.0 and 35 degrees C respectively, and the enzyme was stable at temperature below 50 degrees C and pH 5.0 - 10.0. The lysozyme activity was slightly enhanced by Zn2+ and Cu2+ and slightly inhibited by Mn2+ and Ag+. The lysozyme showed good compatibility to many common chemical agents such as EDTA (0.1%) and KH2 PO4 (1.0%). The lysozyme had broad-spectrum against many bacteria, including a number of pathogens, which were resistant to egg-white lysozyme.

Bacterial Proteins↗

PubMed2004

Inhibitory effect of polypeptide from Chlamys farreri on ultraviolet A-induced oxidative damage on human skin fibroblasts in vitro.

We have previously reported that polypeptide from Chlamys farreri (PCF) inhibits the oxidative damage of ultraviolet A (UVA) on HeLa cells in vitro [Acta Pharm. Sin. 23 (2002) 961]. To further elucidate a possible role for PCF on UVA-damaged normal human cells, we established the oxidative damage models of normal human dermal fibroblasts (NHDF) exposed to UVA to study the protective effect of PCF on human dermal fibroblasts in vitro. In this study, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the cell viability. The intracellular superoxide dismutase (SOD), glutathione peroxidase (GSH-px), catalase (CAT), xanthine oxidase (XOD), malondialdehyde (MDA), reactive oxygen species (ROS), total antioxidative capacity (T-AOC), and anti-superoxide anion capacity (A-ASC) were measured. The effect of PCF on UVA-induced apoptosis were investigated by Annexin V-FITC assay. Intracellular calcium was determined with the calcium-sensitive fluorochrome Fluo-3, and mitochondrial transmembrane potential with rhodamine 123. Comet assay was employed to detect the UVA-induced DNA damage. The ultrastructure of cell was observed under transmission electron microscope. The results indicated that PCF could greatly enhance the viability of NHDF and markedly promote SOD, GSH-px, T-AOC, and A-ASC, while the amounts of MDA and ROS, the activity of XOD were decreased. PCF could inhibit UVA-induced apoptosis and DNA damage in NHDF. The concentration of cellular free calcium was decreased and the mitochondrial transmembrane potential was increased by PCF. In ultrastructure of NHDF, PCF could greatly decrease UVA-induced damage, especially membrane. Our results suggest that the supplementation of PCF appears to reduce the UVA-induced normal human dermal fibroblasts damage efficiently. It may be involved in the PCF's abilities of scavenging oxygen free radical, inhibiting lipid peroxidation, increasing antioxidative enzymes, decreasing intracellular calcium and protection of membrane structure in NHDF irradiated by UVA.

Animals↗

PubMed2004

[Study on low-temperature alkaline lipase from Bohaisea-9145].

Lipase-overproducing marine yeast Bohaisea-9145 isolated from the Bohai sea region was identified as psychrotrophlic Yarrowia lipolytica. The optimum composition of culture medium was ground soybean 4%, rice bran 4%, peanut power 4%, crude peanut oil 0.5%, MgSO4 0.05%, KH2PPO4 0.2%. The optimum temperature and pH were 26 +/- 1 degrees C pH5.0, the time of fermentation cycle was 23h. The lipase activity was improved to 258.67 U/mL through optimization, four-fold more than that of initial strain. The lipase displayed maximum activity at pH 8.5, 35 degrees C and was stable within the range of pH 4.0 - 9.0 at low temperature. It had high thermosensitivity, good compatibility with familiar metal ions and chemical reagents. It was antioxidant and had strong resistance to high salinity. As a novel marine low-temperature lipase, it has promising prospect in many fields, especially as an additive of detergent.

Lipase↗

PubMed2003

Protective effect of polypeptide from Chlamys farreri on mitochondria in human dermal fibroblasts irradiated by ultraviolet B.

AIM: To study the effect of polypeptide from Chlamys farreri (PCF) on mitochondria of human dermal fibroblasts irradiated by ultraviolet B (UVB) in vitro. METHODS: Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were determined by biochemical methods. Mitochondrial transmembrane potential was measured by flow cytometry. Ultrastructure of fibroblasts was observed with transmission electron microscope. RESULTS: UVB (1.176 x 10(-4) J/cm(2)) induced mitochondria damage in dermal fibroblast and PCF (0.25%-1%) reduced the damage in a concentration-dependent manner. Furthermore, PCF also concentration-dependently maintained the stability of mitochondrial transmembrane potential. PCF was able to reduce the MDA formation caused by UVB, meanwhile increased the activities of SOD and GSH-PX. The differences among the PCF groups and UVB model group were significant (P<0.05, P<0.01). CONCLUSION: The UVB-induced mitochondria damage was alleviated by PCF in human dermal fibroblasts.

Adolescent↗

PubMed2002

Protective effect of polypeptide from Chlamys farreri on hairless mice damaged by ultraviolet A.

AIM: To study the protective effect of the polypeptide isolated from Chlamys farreri (PCF) on hairless mice skin damaged by ultraviolet A. METHODS: Enzymes and malondialdehyde (MDA) were determined by biochemical methods; the expressions of Bcl-2 protein and NOS protein were examined by immunohistochemical technique. The ultra-structure of the skin was observed through electronic microscope. RESULTS: PCF could enhance the activities of glutathione peroxidase (GSH-px), superoxide dismutase (SOD), and total anti-oxidative capacity (T-AOC). Also PCF could reduce the amount of MDA, increase the expression of Bcl-2 protein, and inhibit the expression of NOS protein. The ultra-structure of epidermis and fibroblasts remained normal in 20 % PCF groups; there were vacuoles in smooth endoplasm reticulum in epidermis of mice and the number of rough endoplasm reticulum in fibroblasts was decreased in model group. CONCLUSION: PCF had the protective effects on hairless mice skin damaged by ultraviolet A via its anti-oxidative mechanisms.

Animals↗