Biomedical subjects

Jian-Ye Chen

Publications and source records attributed to Jian-Ye Chen.

5 recordsLinked to original sources

PubMed2006

Activity and subcellular localization of glucose-6-phosphate dehydrogenase in peach fruits.

The subcellular distribution and activity of glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) were studied in developing peach (Prunus persica L. Batsch cv. Zaoyu) fruit. Fruit tissues were separated by differential centrifugation at 15,000g into plastidic and cytosolic fractions. There was no serious loss of enzyme activity (or activation) during the preparation of fractions. G6PDH activity was found in both the plastidic and cytosolic compartments. Moreover, DTT had no effect on the plastidic G6PDH activities, that is, the redox regulatory mechanism did not play an important role in the peach fleshy tissue. Results from the immunogold electron-microscope localization revealed that G6PDH isoenzymes were mainly present in the cytosol, the secondary wall and plastids (chloroplasts and chromoplasts), but scarcely found in the starch granules or the cell wall. In addition to a decrease in fruit firmness, the G6PDH activity in the cytotolic and plastidic fractions increased, and anthocyanin started to accumulate during fruit maturation. These results suggest that G6PDH, by providing precursors for metabolic processes, might be associated with the red coloration that occurs in peach fruit.

Anthocyanins↗

PubMed2006

[Inhibitory effect of human brain myelin basic protein on H2O2-induced apoptosis of human lung cancer cell line YTLMC-90].

BACKGROUND & OBJECTIVE: Human brain myelin basic protein (MBP) distributes in nervous system and other tissues extensively, and can be detected in many kinds of tumor cells, such as lung cancer, breast cancer, and neuroglioma. However, it has not been reported whether MBP is relevant to the activity of neural invasion of tumors and whether MBP plays a role in biological behaviors of human lung cancer cells. This study was to investigate the inhibitory effect of MBP on hydrogen peroxide (H2O2)-induced apoptosis of human lung cancer cell line YTLMC-90. METHODS: YTLMC-90 cells were transfected with plasmid pSVCEPMBPCAT containing MBP cDNA minigene (test group), or empty vector pSVCEPCAT, or received no transfection (control group), and exposed to H2O2. The expression of MBP in YTLMC-90 cells was detected by Western blot. Cell proliferation was measured by MTT assay. The morphologic and ultra-structural changes of apoptotic cells were observed by microscopy with fluorescent staining of acridine orange (AO) and electron microscopy. The DNA fragmentation was examined by agarose gel electrophoresis. RESULTS: After exposed to 200 micromol/L H2O2 for 24 h, the inhibitory rate of cell growth was significantly lower in test group than in empty vector group and control group (36.67% vs. 78.67% and 84.00%, P<0.001). The morphologic and biochemical changes of apoptotic cells, such as shrinkage of cytoplasm and nucleus, fragmentation of chromatin, and ladder pattern of DNA, were commonly observed in cells in control group, but these apoptotic features were not discovered in test group. CONCLUSION: MBP markedly inhibits H2O2 cytotoxicity to YTLMC-90 cells through promoting cell proliferation and antagonizing H2O2-induced apoptosis.

Apoptosis↗

PubMed2005

Changes and subcellular localizations of the enzymes involved in phenylpropanoid metabolism during grape berry development.

The phenylpropanoid pathway yields a variety of phenolics that are closely associated with fruit qualities in addition to structural and defense-related functions. However, very little has been reported concerning its metabolism in fruit. This experiment was designed to assess changes of eleven phenolic acids in grape berry (Vitis vinifera L. cv. Cabernet Sauvignon) and explore both the activities and amounts of three key enzymes--phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate:coenzyme A ligase (4CL)--catalyzing the biosynthesis of these compounds during berry development. Finally, the subcellular localizations of the enzymes within berry tissues were also investigated using immuno-gold electron microscopic technique. The results indicated that the contents of gallic, protocatechuic, gentisic and caffeic acid all changed drastically during berry development, while other compounds containing p-hydroxybenzoic, vanillic, syringic, chlorogenic, p-coumaric, ferulic and sinapic acid varied only slightly. Activities of PAL, C4H and 4CL showed similar pattern changes with two accumulated peaks throughout berry development. In addition, their activities all showed a highly positive correlation with the total contents of phenolic acids, whereas the immunoblotting analysis showed that changes in enzyme activities were independent of the enzyme amounts. Results from the subcellular-localization study revealed that PAL was mainly present in the cell walls, secondarily thickened walls, and the parenchyma cells of the berry mesocarp cells, C4H was found primarily in the chloroplast (plastid) and nucleus and 4CL predominantly in the secondarily thickened walls and the parenchyma cells of mesocarp vascular tissue.

Coenzyme A Ligases↗

PubMed2003

[Suppressive effect of brain derived neurotrophic factor on H2O2-induced apoptosis in human lung cancer cell YTMLC-90].

BACKGROUND & OBJECTIVE: It has been shown that neurotrophic factors such as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), and neurotrophin (NT-3/4) are synthesized in a variety of cells inside and outside the nervous system. These factors are not only able to promote neural survival, proliferation and apoptosis of neural cells but also relevant to the activity of neural invasion of tumors. It has not been reported to date whether BDNF may play roles in the biological behavior of human lung cancer cells. The aim of this experiment was to investigate the effect of BDNF on hydrogen peroxide (H2O2)-induced apoptosis in the human lung cancer cell line YTMLC-90. METHODS: The minigene pSVCEPBFCAT containing the promoter and enhancer elements of the human a1(I) collagen gene(COLIA1) at its 3' terminus followed by hBDNF gene cDNA was transfected and derived BDNF ectopic expression in the human lung cancer cells. The cell proliferation was measured by MTT assay. The morphological and ultra-structural changes of apoptotic cells were observed by microscopy with fluorescent stain of acridine orange and electron microscopy. The DNA fragmentation was examined by agarose gel electrophoresis. RESULTS: After exposure of growing cells to 200 micromol/L H2O2 for 24 hours, the inhibition rate of cell growth was 30% in the pSVCEPBFCAT-transfected YTMLC-90, 84.60% in controls of non-transfected YTMLC-90, and 80.00% in pSVCEPCAT-transfected YTMLC-90, respectively (P< 0.001). The morphological and biochemical changes of apoptotic cells such as shrinkage of cytoplasm and nucleus,fragmentation of the chromatin, and ladder pattern of DNA were commonly observed in the cell population of controls, but these apoptotic features were not discovered in the pSVCEPBFCAT-transfected YTMLC-90. CONCLUSION: BDNF markedly inhibits H2O2 cytotoxicity on human lung cancer cell YTMLC-90 by promoting YTMLC-90 proliferation and antagonizing H2O2-induced apoptosis.

Apoptosis↗

PubMed1996

A Structure-function Analysis of the Human Ciliary Neurotrophic Factor.

The ciliary neurotrophic factor (CNTF) plays a very important role in the development and regeneration of the nervous system. In this study, the prediction of secondary structure and the hydrophobicity analysis of human CNTF were performed according to the amino acid sequence deduced from the nucleotide sequence of the cDNA. Based on the results of the prediction of structure, the human CNTF gene was modified by insertion and deletion mutagenesis. The various mutants were all highly expressed in E. coli. The recombinant proteins were purified from bacterial via DEAE A-50 and Sephacryl S-200 chromatography, and their survival-promoting activities were determined by using cultures of the dorsal root ganglion neurons of embryonic chick. The results showed that the alpha-helixes in CNTF were critical for the biological activity and the flexible C-terminus of human CNTF was not essential. Our data also indicated that the middle and the tail part of the D-helix might play crucial roles in the biological functions of CNTF.

Journal Article↗