Biomedical subjects

Guo-Ping Sun

Publications and source records attributed to Guo-Ping Sun.

6 recordsLinked to original sources

PubMed2007

Antiproliferation and apoptosis induction of paeonol in HepG2 cells.

AIM: To investigate the antiproliferative effect of paeonol (Pae) used alone or in combination with chemotherapeutic agents [cisplatin (CDDP), doxorubicin (DOX) and 5-fluorouracil (5-FU)] on human hepatoma cell line HepG2 and the possible mechanisms. METHODS: The cytotoxic effect of drugs on HepG2 cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Morphologic changes were observed by acridine orange (AO) fluorescence staining. Cell cycle and apoptosis rate were detected by flow cytometry (FCM). Drug-drug interactions were analyzed by the coefficient of drug interaction (CDI). RESULTS: Pae (7.81-250 mg/L) had an inhibitory effect on the proliferation of HepG2 cells in a dose-dependent manner, with the IC50 value of (104.77 +/- 7.28) mg/L. AO fluorescence staining and FCM assays showed that Pae induced apoptosis and arrested cell cycle at S phase in HepG2 cells. Further, different extent synergisms were observed when Pae (15.63, 31.25, 62.5 mg/L) was combined with CDDP (0.31-2.5 mg/L), DOX (0.16-1.25 mg/L), or 5-FU (12.5-100 mg/L) at appropriate concentrations. The IC50 value of the three drugs decreased dramatically when combined with Pae (P < 0.01). Of the three different combinations, the sensitivity of cells to drugs was considerably different. CONCLUSION: Pae had a significant growth-inhibitory effect on the human hepatoma cell line HepG2, which may be related to apoptosis induction and cell cycle arrest. It also can enhance the cytotoxicity of chemotherapeutic agents on HepG2 cells, and the S phase arrest induced by Pae may be one of the mechanisms of these interactions.

Acetophenones↗

PubMed2006

[Properties of a triphenylmethane dyes decolorization enzyme TpmD from Aeromonas hydrophila strain DN322].

A novel bacterial decolorization enzyme for triphenylmethane dyes from Aeromonas hydrophila strain DN322 was purified, named TpmD. The purified enzyme catalyzes the decolorization of several triphenylmethane dyes, i.e., crystal violet, basic fuchsin, brilliant green and malachite green. The enzyme was identified by the clear transparent band development of zymogram stained with crystal violet, basic fuchsin, brilliant green and malachite green after polyacrylamide gel electrophoresis (PAGE) respectively. The decolorization enzyme was enzymologically characterized. The results showed that the molecular weight of TpmD is 29.4kDa and its isoelectric point (pI) is 5.6. The maximal activity of TpmD for above four triphenylmethane dyes was observed at 50 degrees C - 55 degrees C and pH 7.4 - 8.0. The temperature for losing half of the activity (t1/2) within 4h is 62 degrees C. The activities of decolorization enzyme are relatively stable at pH range of 5.5 - 9.0. The K(m) and V(max) of TpmD for decolorizing crystal violet, basic fuchsin, brilliant green and malachite green are 24.3, 40.6, 54.2, 68.5 micromol/L respectively, V(max) are 19.6, 74.1, 82.8, 115.6 micromol x L(-1) x s(-1) respectively. Both NADH/NADPH and molecular oxygen are necessary for the enzyme to decolorize triphenylmethane dyes, indicate the enzyme is an NADH/NADPH-dependent oxygenase.

Aeromonas hydrophila↗

PubMed2006

[Isolation and characterization of a facultative anaerobic aniline-degrading bacterium].

An aniline-degrading bacterium (designated strain AN29) was isolated from dyeing wastewater process (anaerobic baffled reactor, ABR) with the capability of utilizing aniline as sole carbon source and nitrogen source. It was identified as Pseudomonas sp. based upon the phenotypic properties and a partial analysis of the 16S rDNA. The strain could degrade aniline under the aerobic and anaerobic conditions, the optimal initial pH 6.5 - 8.0, a temperature of 37 degrees C, and initial aniline concentrations of 500 - 2 000 mg/L with maximum concentration of 4 000 mg/L respectively.

Aerobiosis↗

PubMed2006

[Properties of a triphenylmethane dyes decolorization enzyme (TpmD) from Aeromonas hydrophila strain DN322].

A novel bacterial enzyme for decolorization of triphenylmethane dyes from Aeromonas hydrophila strain DN322 was purified and named TpmD. The basic properties of this enzyme including molecular weight, isoelectric point Km as well as the optimum temperature and pH were determined and the enzyme was identified as an NADH/NADPH-dependent oxygenase in previous research. Based on previous results, the effect of different inhibitor including Vc, metyrapone, rotenone, antimycin A and NaN3 as well as the effect of FAD and FMN on the activity of TpmD were measured. The results indicated that the activity of the decolorization enzyme was inhibited by Vc and metyrapone in a concentration-dependent manner, but wasn't inhibited by rotenone, antimycin A and NaN3. The activity of the decolorization enzyme was not enhanced by addition of FAD or FMN. The solution of the enzyme protein displayed only a single peak at 408nm in the Soret region, a characteristic peak of porphyrin, but did not show the characteristic peak of the cytochrome P450 proteins at 450nm in sodium dithionite (DTN)-reduced enzyme solution after treatment with carbon monoxide. The amino acid sequence of N-terminal of TpmD provided further evidence that the enzyme is an oxygenase. All these results suggest that decolorization enzyme TpmD is a new hemo-containing oxygenase. The decolorization enzyme would be a good material for further research of the enzymological mechanism of triphenylmethane dyes decolorization by bacteria.

Aeromonas hydrophila↗

PubMed2005

[Cloning and analysis of genes encoding 2-naphthoate monooxygenase and NADH:flavin oxidoreductase].

In Burkholderia sp. JT1500, a key step of 2-naphthoate biodegradation pathway is carried out by 2-naphthoate monooxygenase (Nmo) in which 2-naphthoate is oxidized to 1-hydroxy-2-naphthoate. A gene cluster of 4.8kb from Burkholderia sp. JT1500 was cloned and sequenced, four open reading frames named orfB, orfC, orfD and orfA were identified in this region. Sequence alignment showed that orfA had a high homology of nucleotide acid composition to monooxygenase genes from both Japonicum USDA 110 and Ralstonia eutropha HF 39, orfB had some homology to the component of flavin reductase genes from Bordetlla pertussis Tohama I, Ralstonia solanacearum GMI1000 and Bordetella bronchiseptica RB50. Enzyme activity analysis showed that the cell extracts of recombinant E. coli S(A) (only harboring orfA) showed very low oxygenase oxidation activity as detected by NADH decreasing, while the cell extracts of recombinant S(B) (only harboring orfB) did not show any oxidation activity at all. But when the cell extracts of S(B) and S(A) were mixed, which showed very strong oxidation activity when flavin (FMN or FAD) provided; the recombinant S(B + A) cells harboring both orfB and orfA genes also showed strong oxidation activity when flavin provided; weak flavin deoxidization activity could be detected from the cell extracts of E. coli S(B) under anaerobic conditions. Based on above message, a conclusion was drawn that Nmo is consisted of two components: a flavin oxidoreductase (NmoB) and a monooxygenase (NmoA). First NmoB uses NADH to reduce flavin and supplies reduced flavin to NmoA to catalyze O2 oxidizing 2-NAT. NmoB is NmoA' s coupling protein.

Chromatography, High Pressure Liquid↗

PubMed2005

[Bacterial Fe(III) reduction].

Bacterial Fe(III) reduction is an important pathway of bioenergy metabolism in the process of life evolution. Many kinds of archaebacteria and eubacteria are capable of reducing Fe(III) to conserve energy. Anaerobic Fe(III) respiration pathway involves many membranous proteins and regulating factors, especially the muti-haem c-type cytochromes are very important in the course of electron transportation. In addition, bacterial Fe(III) reduction play important roles in the biological geochemistry circulation and environmental remediation, therefore has vital environmental significance.

Bacteria↗