Baeyer-Villiger monooxygenases (BVMOs) are important biocatalysts to synthesize a series of valuable esters and lactones. Based on protein sequence alignment and crystal structure analysis, a nonconserved hinge which linked NADPH domain and FAD domain was speculated to play an important role in substrate recognition and catalytic oxidation process. Cyclohexanone monooxygenase (CHMO) was selected as a model. Mutants obtained by homologous replacement of the whole hinge almost completely lost its original catalytic activity, demonstrating that the overall hinge structure was of great importance. Some significant sites were identified to greatly affect the catalytic activity and stereoselectivity by alanine scanning mutagenesis, accompanied by enzyme activity assessments and chiral kinetic resolutions. Altering K153 decreased the activity of the enzyme but enhanced the stereoselectivity. Changing L143 site reduced stereoselectivity but had little effect on enzyme activity. Mutation at L144 site dramatically weakened both activity and stereoselectivity. Subsequently, these corresponding sites in phenylacetone monooxygenase were also illustrated to follow a similar rule, revealing a universal importance of these sites in the BVMO family. These results expanded our understanding of the structure-activity relationship of these enzymes and provided more proofs for future directed evolution of BVMOs.
Amino Acid Sequence ; Catalysis ; Mixed Function Oxygenases ; chemistry ; Models, Molecular ; NADP ; Oxidation-Reduction ; Oxygenases ; chemistry ; Protein Conformation ; Sequence Alignment ; Structure-Activity Relationship ; Substrate Specificity

Objective To evaluate the influence of SP600125,a selective c-Jun N-terminal kinase (JNK) inhibitor,on the levels of serum total bile salt (TBA) and Bsep,Ntcp expression in the hepatic tissue of rats with ethinylestradiol induced intrahepatic cholestasis.Methods Rats pregnant for 15days were administered the subcutaneous injection of 17- b -estradiol propylene ( EE ) to modulate the ICP animal models,and be SP600125 to intervene.Testing the level of serum TBA and the expression of c-Jun,Bsep,Ntcp in the hepalatic tissue.Results The average gray values of c-Jun in the group of ICP models were significantly lower than the normal control group ( 101.05 ± 5.20 vs 118.99 ± 5.95,P ＜ 0.05 ).After the intervention of SP600125,comparing with the group of ICP models,the expression of Bsep,Ntcp in the group of SP600125 intervention were significantly higher,and this change in the high dose of SP600125 intervention group was more obvious ( low dose intervention group Bsep:0.452 ±0.031 vs 0.291 ±0.043,Ntcp:0.462 ± 0.015 vs 0.285 ± 0.021,P ＜ 0.05 ; high dose intervention group Bsep:0.568 ± 0.038 vs 0.291 ±0.043,Ntcp:0.605±0.020 vs 0.285 ±0.021,P ＜0.05),while the level of TBA in the serum was significantly lower.Conclusions Treatment with SP600125 can down-regulate the level of c-Jun/AP-1,and it may participate in the lower expression of Bsep、Ntcp in the ICP rats which were induced by 17-bestradiol.

Objective To study the effect of SDF1/CXCR4 and FN/?1 integrin modulated by curcumin on the adhesion and migration of B lymphoma Raji cell and to explore the mechanism of curcumin to inhibit the invasiveness of lymphoma.Methods The experiment consisted of eight groups: Control,FN,SDF,FN+anti-?1 integrin,SDF+anti-CXCR4,curcumin+FN,curcumin+SDF.Adhesion assay and migration assay were used to detect the difference of invasiveness among different groups.Results In vitro,SDF1 and FN can increase the adhesion and migration of Raji cells,which can be blocked by ?1 integrin antibody and CXCR4 antibody.Curcumin can inhibit the adhesion and migration of Raji to FN in a dose-dependant manner.Low dosage curcumin had minimal effect on the adhesion and migration of Raji induced by SDF except that 25?mol/L curcumin can inhibit the adhesion and migration of Raji.Conclusion FN/?1 integrin and SDF1/CXCR4 pathway play important roles in the adhesion and migration of Raji cells.Curcumin can decrease the invasiveness of Raji cells through inhibiting FN/?1 integrin.It has good prospect of clinical application.

AIM:To investigate the inhibitory effects of triptolide on cell proliferation and metastasis in Burkitt's lymphoma cell line Raji cells.METHODS: The effects of triptolide on the growth of Raji cells were studied by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium(MTT) assay.The effects of triptolide on the cell apoptosis of Raji cells were detected by using Annexin Ⅴ/PI double-labled cytometry.The effects of triptolide on CXCR4 expression on Raji cells were studied by flow cytometric analysis.Chemotaxis assays were performed to observe the effects of triptolide on migration of Raji cells towards recombinant human SDF-1?(rhSDF-1?)in vitro.RESULTS: Triptolide inhibited the proliferation of Raji cells in a dose-and time-dependent way with a 24 h IC50 value of 43.06 nmol/L and a 36 h IC50 value of 25.08 nmol/L.Following the treatment of triptolide,the cell apoptosis rate was increased as the treatment concentration increased and the culture time extended.The effects were dose-and time-dependent.Triptolide could downregulate the expression of CXCR4 on Raji cells in a dose-dependent manner.Moreover,chemotaxis assay suggested that triptolide could block the migration of Raji cells to rhSDF-1? in vitro,and the inhibition was dose-dependent.CONCLUSION: Triptolide could inhibit the cell proliferation and induce the cell apoptosis of Raji cells.Furthermore,it could block the cell metastasis of Raji cells in vitro and the underlying mechanism might be related to the inhibition of the SDF-1/CXCR4 axis.

OBJECTIVE To survey the current situation of disinfection and supply rooms in 34 hospitals of Hubei Province under the Committee of Hubei Distinfection.METHODS On the basis of certain references,an questionaire was designed to survey on site.RESULTS All 34 hospitals were taken disperse control mode of disinfection;the education was not good enough;most of the disinfection and supply rooms covered limited space,without meeting the standards of Ministry of Health.The rate of equipement usage was low;the working spheres were narrow.CONCLUSIONS There is not any control mode of disinfection and supply rooms in these 34 hospitals;if working staff and equipment are improved,the working spheres can be broaden.it should be transferred to the centralized control mode of disinfection.

Objective To understand psychiatry hospital nurse' s self-compassion situation, explore the influencing factors, for nursing managers to know about the clinical nurses psychological health and to provide a reference data of intervention to improve the level of self-compassion. Methods A total of 381 clinical nurses from the Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital) completed the survey using the questionnaire including the Self-Compassion Scale (SCS) and general information questionnaire. The influence factors were analyzed by chi-square test and Logistic regression analysis. Results The total score of SCS was (85.43 ± 10.23) points in 381 clinical nurses with the medium level, which was less than that of other nurse group (109.21±9.76) points, and there was significant difference(t=-45.388, P < 0.01).The Logistic regression analysis showed that female and working in the psychiatric ward were the risk factors of self compassion(OR=1.772, 1.995, P<0.05 or 0.01). While on the night shift was the protective factor(OR=0.536, P < 0.01). Conclusions Psychiatric hospital nurse' s self-compassion is at medium level. When the nurses cope with the negative events may lack adjustment method. Nursing managers should pay attention to train the ability of the nurse individual self-compassion, targeted to carry out active intervention measures.

In order to investigate the anti-cancer effects of deguelin and on K562 and K562/ADM cells in vitro and the underlying molecular mechanism and compare the cytotoxicity of deguelin on K562, K562/ADM cells and human peripheral blood mononuclear cells (PBMCs). The effects of deguelin on cell proliferation were assessed by MTT assay. Apoptosis were detected by Annexin V/PI double-labeled cytometry. The effects of deguelin on the cell cycle were studied by a propidium iodide method. Our study showed that deguelin inhibited the proliferation of K562 cell and K562/ADM cell in a time- and dose-dependent manner and had minimal effects on normal human peripheral blood mononuclear cells. The ratio of IC(50) value of deguelin of 24 h on K562/ADM cells to K562 cells was only 1.27, which was significantly lower than the ratio of IC(50) value of ADM (higher than 20). Deguelin could induce apoptosis of K562 cells and K562/ADM cells. K562 cells were arrested at G(2)/M phase while K562/ADM cells were arrested at G(0)/G(1) phase. Our results suggested that deguelin was a novel anti-leukemia agents with high efficacy and low toxicity and it is also a promising agent for reversing drug resistance.

The effects of betulinic acid (BA), a pentacyclic lupane-type triterpene, on the cell viability, cell cycle and apoptosis in human leukemia K562 cells were investigated. The effects of BA on the growth of K562 cells were studied by MTT assay. Apoptosis was assayed through Annexin V/propidium iodide (PI) double-labeled cytometry. The effects of BA on the cell cycle of K562 cells were studied by a PI method. The expression of Bax and capase-3 was detected by using Western blot. The results showed that BA was cytotoxic to K562 cells with an IC(50) of 21.26 mug/mL at 24 h. After treating K562 cells with 10 mug/mL BA for 72 h, the number of cells was reduced by 58%. BA induced apoptosis of K562 cells in a time- and dose-dependent manner. The proportion of cells in G(0)/G(1) and G(2)/M phases was decreased and that in S phase was increased after K562 cells were treated with BA for 24 h. BA treatment also increased the expression of the pro-apoptotic proteins Bax and caspase-3. It suggested that BA could inhibit the proliferation of K562 cells through the induction of cell cycle arrest and apoptosis. The antitumor effects of BA were related with up-regulation of the expression of Bax and caspase-3 proteins. BA may qualify for the development of new therapies for leukemia.

The anti-cancer effects of betulinic acid (BA) on Jurkat cells and its in vitro mechanism were examined by using MTT assay. Apoptosis was detected by using Hoechst33258 staining and annexin-V/PI double-labeled cytometry. The effects of betulinic acid on the cell cycle of Jurkat cells were studied by propidium iodide method. RT-PCR and Western blotting were used to analyze the changes of cyclin D3, bcl-xl mRNA and protein levels in Jurkat cells after treatment with betulinic acid. Our results showed the proliferation of Jurkat cells was decreased in betulinic acid-treated group with a 24-h IC50 value being 70.00 mumol/L. Betulinic acid induced apoptosis of Jurkat cells in a time- and dose-dependent manner. The number of Jurkat cells treated with betulinic acid showed an increase in G(0)/G(1) phase and decrease in S phase. After treatment with 0, 20, 60, 100 mumol/L betulinic acid for 24 h, the number of Jurkat cells was increased from (31.00+/-1.25)% to (58.84+/-0.32)% in G(0)/G(1) phase, whereas it was decreased from (61.45+/-1.04)% to (35.82+/-1.95)% in S phase. PBMCs were less sensitive to the cytotoxicity of betulinic acid than Jurkat cells. The expressions of cyclin D3, bcl-xl mRNA and protein were decreased sharply in Jurkat cells treated with betulinic acid. It is concluded that betulinic acid is able to inhibit the proliferation of Jurkat cells by regulating the cell cycle, arrest cells at G(0)/G(1) phase and induce the cell apoptosis. The anti-tumor effects of betulinic acid are related to the down-regulated expression of cyclin D3 and bcl-xl.
Antineoplastic Agents, Phytogenic/*pharmacology ; Apoptosis/*drug effects ; Cell Proliferation/*drug effects ; Cyclin D3/metabolism ; Down-Regulation/drug effects ; Jurkat Cells ; Triterpenes/*pharmacology ; bcl-X Protein/metabolism

DNA repair processes play a role in the development of drug resistance which represents a huge obstacle to leukemia chemotherapy. Histone H2AX phosphorylation (ser139) (γH2AX) occurs rapidly at the onset of DNA double strand break (DSB) and is critical to the regulation of DSB repair. If DNA repair is successful, cells exposed to anti-neoplastic drugs will keep entering the cycle and develop resistance to the drugs. In this study, we investigated whether γH2AX can be used as an indicator of tumor chemosensitivity and a potential target for enhancing chemotherapy. K562 and multi-drug resistant cell line K562/A02 were exposed to adriamycin (ADR) and γH2AX formed. Flow cytometry revealed that percentage of cells expressing γH2AX was increased in a dose-dependent manner and the percentage of K562/A02 cells was lower than that of K562 cells when treated with the same concentration of ADR. In order to test the potential of γH2AX to reverse drug resistance, K562/A02 cells were treated with PI3K inhibitor LY294002. It was found that LY249002 decreased ADR-induced γH2AX expression and increased the sensitivity of K562/A02 cells to ADR. Additionally, the single-cell gel electrophoresis assay and the Western blotting showed that LY249002 enhanced DSBs and decreased the expression of repair factor BRCA1. These results illustrate chemosensitivity can partly be measured by detecting γH2AX and drug resistance can be reversed by inhibiting γH2AX.