1.Research Advance in Recombinant Expression of Microbial Lipases
China Biotechnology 2006;0(05):-
Microbial lipases have been widely used in traditional industries,as well as in emerging biocatalysed areas owing to their ability to catalyze a variety of reactions in aqueous and non-aqueous media.Therefore,it is very important to enhance amount of lipase production by recombinant overexpression for meeting market demand.A critical review of main and novel strategies which have been employed for recombinant expression of microbial lipases are presented,including codon optimization,fusion and co-expression,dual expression system based on hybrid promoters,homologous overexpression,cell surface displaying and high-throughput screening based on gene library of expression.These new technologies are gradually coming to the forefront in the recombinant expression of lipase,especially for cell surface displaying and high-throughput screening based on gene library of expression.Meanwhile,several recombinant expressions for representative microbial lipases were also introduced and discussed,which are available for consultation when attempting to overexpress any lipases by scientists and industrialists.
2.AZT inhibit telomerase activity of squamous cell carcinoma of tongue
China Oncology 2001;0(02):-
Purpose:To study the effect of inhibition of telomerase activity and cell cycle by transcriptase telomerase inhibitors (3′ azido 3′ deoxythymidine, AZT) on squamous cell carcinoma of tongue in vitro.Methods:Human squmous cell carcinoma of tongue cell line Tca8113 was used as target cell. Telomerase activity was determined by TRAP PCR ELISA in untreated and treated Tca8113 by AZT, cell cycle phases were analyzed by flow cytometry. Results:Telomerase activity of Tca8113 was significantly inhibited when treated with AZT, and the effect of inhibition was dose dependant (rate of telomerase activity treated with AZT in 0.3, 0.6, 1.0, 1.5mol 10 -1 was 0.69 0.03, 0.61 0.08, 0.53 0.11, 0.50 0.02 respectively, rate of telomerase activity treated without AZT was 0.76 0.06). Cell cycle of treated Tca8113 was changed with marked increase in G 2 /M phase compared with untreated Tca8113 (62.8% vs 19.7%, P
3.Determination of Capsaicine, Dihydrocapsaicin, Imperatorin and Isoimperatorin in Guanjie Jietong Plas-ters by HPLC
China Pharmacist 2014;(11):1965-1967
Objective:To develop an HPLC method for the determination of capsaicine, dihydrocapsaicin, imperatorin and isoim-peratorin in Guanjie Jietong plasters. Methods:A CAPCELL PAK C18 column was used as the chromatographic column, and the flow rate was 0. 8 ml·min-1. The mobile phase A consisted of methanol-acetonitrile(1∶1), the mobile phase B was of 1% phosphoric acid. The detection wavelength was 280 nm and 254 nm, respectively. Results:There was a good linear relationship between the con-centrations and the peak areas within the range of 0. 298-5. 956μg(r=0. 9998) for capsaicine, 0. 152-3. 044μg(r=0. 999 6) for di-hydrocapsaicin, 0. 018-0. 352 μg(r=0. 999 5) for imperatorin and 0. 010-0. 204 μg(r=0. 999 3) for isoimperatorin. The average re-covery was 97. 8%(RSD=1. 02%), 97. 0%(RSD=0. 76%), 96. 6%(RSD=0. 65%) and 98. 1%(RSD=1. 35%), respectively. Conclusion:The method is convenient, accurate, sensitive and repeatable, which can be used in the determination of capsaicine, di-hydrocapsaicin, imperatorin and isoimperatorin in Guanjie Jietong plasters.
4.Up-regulating effect of hepatitis C virus core protein on inducible nitric oxide synthase gene promoter
Feng-Jin GUO ; Jun CHENG ; Yan LIU ;
Chinese Journal of Infectious Diseases 1997;0(04):-
Objective To investigate the transactivating effect of hepatitis C virus(HCV)core protein on inducible nitric oxide synthase(iNOS)gene promoter and the molecular biological mecha- nisms of HCV pathogenesis.Methods Polymerase chain reaction(PCR)technique was employed to amplify the sequence of iNOS promoter by using HepG2 genomic DNA as template,and the product was cloned into pGEM-T vector.The iNOSp gene was cut from T-iNOSp by KpnⅠand XhoⅠ,and then was cloned into pCAT3-Basic,the constructed vector was named as pCAT3-iNOSp,pCAT3-iN- OSp was transfected into the LO_2 cell line.LO_2 cell was also cotransfected with pcDNA3.1(-)-core and pCAT3-iNOSp by FuGENE 6 transfection reagents.The LO_2 cells transfected with pCAT3-Basic was used as negative control.The activity of CAT in LO_2 cells was detected by an ELISA kit after 48 hours,which reflected the transactivating function of HCV core protein to iNOS gene promoter.Re- sults The expressive vector pcDNA3.1(-)-core and report vector pCAT3-iNOSp had been construc- ted and confirmed by restriction enzyme digestion and sequencing.The expression of CAT in LO_2 cells transfected with pCAT3-iNOSp and peDNA3,1(-)-core was 11 times as higher as that of pCAT3-bas- ic,and 6 times as higher as that of pCAT3-iNOSp.Conclusion It is suggested that HCV core protein can transactivate iNOS gene promoter.
5.Optimization of Lipase Production Conditions by Geotrichum candidum Y162 Using Single Factor-response Surface Methodology
Jin-Yong YAN ; Jiang-Ke YANG ; Yun-Jun YAN ;
China Biotechnology 2006;0(08):-
The fermentation conditions of lipase production by Geotrichum candidum Y162 were optimized. Initially, the most suitable carbon olive oil, nitrogen source soybean flour and NH4Cl, salt BaCl2 and MgCl2 were selected according to single factorial experiments respectively. Based on the result, screening methodology Plackett-Burman design was used to evaluate the effects of twelve factors related to lipase production and three statistically significant factors olive oil, BaCl2 and NH4Cl were selected. The path of steepest ascent was used to approach the optimal region of lipase production subsequently. Then, the optimal combined concentration for maximum enzyme activity were further optimized by response surface methodology and determined as follows: olive oil 2.35%, BaCl2 0.36%,and NH4Cl 4.69%.The optimization of culture conditions of G.candidum Y162 led to a 2.25-fold increase in lipase production relative to initial result 14.16 U/ml, which indicate that single factor in combination with response surface methodology is an effective method for optimization of lipase production conditions by G.candidum Y162.
7.Relationship between Th17 cell number and Helicobacter pylori-infected chronic gastritis in children
Yulin YUE ; Yan ZHANG ; Jun HAN ; Tianying ZHONG ; Yu JIN
Chinese Journal of Applied Clinical Pediatrics 2014;29(22):1717-1720
Objective To explore the relationship between peripheral Th17 cell number and chronic gastritis in Helicobacter pylori(H.pylori)-infected children.Methods Children were diagnosed as chronic gastritis by endoscopy.The degree and activity of inflammation were graded by histopathology examinations.The patients with both 13C urea breath test and urease test positive were diagnosed as H.pylori infection.The peripheral Th17 cell number was measured by flow cytometry and expressed as a ratio to total T cell.Results The Th17 cell number in HP group (chronic gastritis with H.pylori infection,n =33),non-HP group (chronic gastritis without H.pylori infection,n =24) and normal controls (n =15) were (1.55 ±0.30)%,(1.06 ±0.33)%,and (1.04 ±0.35)%,respectively.HP group included a statistically higher Th17 cell number than the other groups (all P < 0.05),while no obvious difference was found between non-HP group and controls (P > 0.05).According to the degree of inflammation,the chronic gastritis with H.pylori infection was categorized into non-apparent (n =10),mild (n =8),moderate (n =9) and severe (n =6) subgroups.The Th17 cell number in each subgroup was (1.64 ± 0.21)% (non-apparent),(1.61 ± 0.23)%(mild),(1.25 ± 0.29) % (moderate) and (1.75 ± 0.20) % (severe),respectively.The moderate group had a lowest Th17 cell number among 4 groups (P < 0.05).And significant differences did not exit in the other 3 groups (P > 0.05).The HP group patients with different inflammatory activity had a Th17 cell number of (1.23 ±0.25)% in nonapparent (n=15),(1.53 ±0.15)% in mild (n=6),(1.55 ±0.32)% in moderate (n=6) and (1.71 ±0.35)% in severe (n =6) subgroup,respectively.However,there were no significant differences among 4 subgroups (P > 0.05).Conclusions In the progress of chronic gastritis with H.pylori infection,Th17 cells may play a role as a double-edged sword by protecting and fighting against H.pylori infection and immunopathologic insults.This would provide more insights into the treatment of H.pylori infection.
8.Invasive Fungal Infection in ICU:A Retrospective Analysis
Jun LU ; Jin ZHU ; Lifeng XU ; Yan CHEN
Chinese Journal of Nosocomiology 2006;0(02):-
OBJECTIVE To have an retrospective analysis of the prevalent fungi infected in patients in ICU,and their pathologic sites and drug resistance and to find out the hazard factors.METHODS The research used API 20C AUX and Rosco disk diffusion method to test the drug resistance of fungi isolated from the infected samples collected from ICU patients in our hospital between Jan 2006 and Mar 2007.RESULTS Totally 123 fungi strains were spotted,the majority of them being Candida albicans,accounting for 34.1%;Candida glabrata 26.8% and Candida tropicalis 18.7%.All the fungi were sensitive to amphotericin B and nystatin(Mycostatin) and partially resistant to fluconazole,itraconazole and ketoconazole.Patients with long term use of wide-spectrum antibiotics and catheters and elder patients would have higher fungi infection rate.CONCLUSIONS Candida are the major pathogens of fungal infections in ICU.The major infected site is lower respiratory tract.Amphotericin B and nystatin have good sensitivity but higher toxicity.Conazole medicines also have good sensitivity to C.albicans and C.tropicalis.But they are resisted largely by C.glabrata and C.krusei.Reasonable use of bacteriophage and reduction of unnecessary diagnosis and treatment procedures,and early discovery,diagnosis and treatment are keys to prevent and cure the invasive fungal infections.
9.Value of procalcitonin on predicting the severity and prognosis in patients with early ARDS: a prospective observation study
Zhixin YU ; Musen JI ; Xiulan HU ; Jun YAN ; Zhaochen JIN
Chinese Critical Care Medicine 2017;29(1):34-38
Objective To investigate the value of procalcitonin (PCT) on predicting the severity and prognosis in patients with early acute respiratory distress syndrome (ARDS).Methods A prospective observation study was conducted. A total of 113 patients with ARDS undergoing mechanical ventilation admitted to intensive care unit (ICU) of Affiliated People's Hospital ofJiangsu University from October 2012 to April 2016 were enrolled. Based on oxygenation index (PaO2/FiO2), the patients were classified into mild, moderate, and severe groups according to Berlin Definition. Twenty-five healthy volunteers were served as controls. Demographics, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, and Murray lung injury score were recorded. Within 24 hours after diagnosis of ARDS, the serum levels of PCT and C-reactive protein (CRP) were determined by enzyme-linked fluorescence analysis (ELFA) and immune turbidimetric method, respectively. The patients were also divided into survival and non-survival groups according to clinical outcome within 28-day follow-up, and the clinical data were compared between the two groups. Spearman rank correlationwas applied to determine the correlation between variables. The predictive value of the parameters on 28-day mortality was evaluated with receiver operating characteristic curve (ROC). Kaplan-Meier survival curve analysis was used to compare different PCT levels of patients with 28-day cumulative survival rate. Results After excluding patients who did not meet the inclusion criteria and loss to follow-up, the final 89 patients were enrolled in the analysis. Among 89 ARDS patients analyzed, 27 of them were mild, 34 moderate, and 28 severe ARDS. No significant differences were found in age and gender between ARDS and healthy control groups. Infection and trauma were the most common etiology of ARDS (55.1% and 34.8%, respectively). Compared with healthy control group, both CRP and PCT in serum of ARDS group were higher [CRP (mg/L): 146.32 (111.31, 168.49) vs. 6.08 (4.47, 7.89), PCT (μg/L): 3.46 (1.98, 5.56) vs. 0.02 (0.01, 0.04), bothP < 0.01], and the two showed sustained upward trends with the ARDS course of disease. Compared with mild group, severe group had significantly higher APACHE Ⅱ and Murray scores. Spearman rank correlation analysis showed that both serum PCT and CRP in patients with ARDS was correlated well with APACHE Ⅱ score (r values were 0.669 and 0.601, respectively, bothP < 0.001), while PCT was weakly but positively correlated with Murray score (r = 0.294,P = 0.005), but not the case of CRP (r = 0.203,P = 0.052). APACHE Ⅱ score and serum PCT in non-survival group (n = 38) were significantly higher than those of the survival group [n = 51; APACHE Ⅱ score: 26.00 (23.00, 28.50) vs. 21.00 (17.00, 25.00), PCT (μg/L): 6.38 (2.82, 9.49) vs. 3.09 (1.08, 3.57), both P < 0.01], but Murray score and CRP level were similar between survivors and non-survivors. The areas under ROC curve (AUC) of APACHE Ⅱ score and PCT for predicting 28-day mortality were 0.781 and 0.793, respectively, which were better than those of AUC of Murray score and CRP (0.606 and 0.561, respectively, allP < 0.05). The AUC of APACHE Ⅱ score combined with PCT was significantly higher than that of PCT (0.859 vs. 0.793,P = 0.048) or APACHE Ⅱ score alone (0.859 vs. 0.781,P = 0.038). Using a PCT cut-off value of > 4.35μg/L for predicting 28-day mortality, the sensitivity and specificity was 92.2% and 63.2%, respectively, and the positive and negative likelihood ratios were 2.50 and 0.12 respectively. Kaplan-Meier survival curve analysis indicated that the patients whose PCT more than 4.35μg/L, had lower 28-day cummulative survival rate as compared with those with PCT ≤ 4.35μg/L (log-rank test: χ2 = 5.013,P = 0.025).Conclusion The elevated serum PCT level in patients with ARDS seems to be correlated well with the severity of lung injury, and appears to be a useful prognostic marker of outcome in the early phases of ARDS.