A new method for determining transaminase activity based on the color change of the reaction solution was established, by using alanine-dependent transaminase VfTA from Vibrio fluvialis JS17 as the research object coupled with pyruvate oxidase and horseradish peroxidase. After the optimization of the conditions, the linear relationship between VfTA activity units and the absorbance at 400 nm was investigated. This method was also applied to determine the activity of commercial transaminase ATA117. The results showed that the detection limit of transaminase VfTA activity was up to 0. 45 U/mL and the detection limit of ATA117 activity was up to 0. 5 U/mL. The transaminase activity could be quickly judged according to the color depth of the reaction solution.

Diketoreductase can catalyze a double reduction of β,δ-diketo ester to corresponding dihydroxv product with enantiomeric excess(ee)and diastereomeric excess(de)both greater than 99.5%.In order to explore the catalytic mechanism of this unique enzyme,the present study investigated the diketone reduction process and reaction characteristics by diketoreductase.We found that two mono-hydroxy intermediates were produced during the diketone reduction and its reverse reaction.The two intermediates were further separated by C18 column chromatography and structurally confirmed by chiral HPLC with authentic standards.Two mono-hydroxy intermediates could be served as the substrates for the reduction by diketoreductase with different reaction velocities.The formation and disappearance of intermediates were largely affected by temperature and substrate concentration.In addition,steady state kinetics with the two intermediates showed different reaction rates in their disappearance.Collectively,the results indicate that the diketone reduction undergoes a two-step process with the formation of both intermediates,but the disappearance rates for the two intermediates are slightly different.

BACKGROUND:Old femoral neck fractures with senile osteoporosis have more surgical difficulties.There are a lot of intraoperative and postoperative complications and long-term effects are poor.OBJECTIVE:To explore the clinical outcomes of hip arthroplasty in patients with old femoral neck fractures with senile osteoporosis.METHODS:From October 2012 to July 2014,20 patients with old femoral neck fractures and senile osteoporosis were enroled in this study.Posterolateral approach was used to perform hip arthroplasty.Of them,14 patients received primary total hip arthroplasty with biological prosthesis,and 6 patients were subjected to semi-hip arthroplasty with straight shank cylindrical renovated biological prosthesis.RESULTS AND CONCLUSION: The patients were folowed up for 3 to 24 months.Harris score was apparently increased after arthroplasty in patients with old femoral neck fractures and senile osteoporosis compared with pre-arthroplasty.Postoperative radiographs revealed that femoral stem biological fixation was good.Bone fixation was visible in radiographs at 3 months after arthroplasty.These findings suggested that old femoral neck fractures and senile osteoporosis could be treated with hip arthroplasty.To select the type of prosthesis and surgical methods according to the femoral calcar-medulary cavity ratio in patients with old femoral neck fractures and senile osteoporosis can effectively restore the function of hip joint.

To explore the current status of children receiving primary health services at a community health service center in Shenzhen so as to provide references for the formulation of children health care policies.According to the patient electronic data in 2011,the clinical profiles were analyzed for children aged under 7 years seeking the advice of general practitioners (GPs) at Niuhu Community Health Service Center.Children aged under 7 years accounted for 12.4％ of all subjects.The causes of seeing the GPs were as follows:acute upper respiratory.infection(58.2％),acute bronchitis(14.9％),gastroenteritis(5.6％),trauma(3.3％)and dermatitis(3.2％).And no difference existed in the workload between pediatrists and surgeons,internists or herbalists.The common and frequent community diseases may be diagnosed and managed at a community health service center.

Objective To study the clinical effect and application value of micro-plasma beam joint radiofrequency treatment for the striae of pregnancy.Methods 21 female patients with the striae of pregnancy were included in this study,treated from the July 2012 to March 2014,aged 25-37 years;and time of the striae was from 3 months to 7 years.Micro-plasma radiofrequency technology was used to treat the striae,with interval of 30 days each time for total seven months.The total effective rate,satisfaction,and the adverse reaction were evaluated after the treatment.Results 21 patients included grade 4 in 6 cases,grade 6 in 10 cases,grade 2 in 4 cases and grade 1 in 1 case;the total effective rate was 95.2％ (20/21).Satisfactory degree was for the level C in 6 cases,B in 14 cases,and A in 1 case,with total satisfactory rate of 95.2％ (20/21).Adverse reactions included mild pigmentation in 2 patients after scab skin falling off,and disappeared at the end of the treatment course.Conclusions Micro-plasma beam combined with radio frequency in treating the striae of pregnancy has clear curative effect and good clinical application value.

NAD(P)(H)-dependent oxidoreductase catalyzes the reduction of ketones or aldehydes to prepare a wide variety of valuable chiral alcohols or amines. However, expensive cofactors are absolutely required for the biocatalytic processes with oxidoreductases, which severely hinder their industrial applications. Consequently, the issue on reducing cofactor costs has become one of the major focuses in the field of biocatalysis. With the substantial development in recent years, a number of strategies have been proposed and implemented to solve the cofactor issues in the oxidoreductase catalyzed biocatalysis, including the establishment of cofactor regeneration system, the improvement of endogenous cofactor availability via metabolic engineering and the development of biomimetic agents to replace cofactors. In this review, recent trends and advances on these strategies are presented, and respective advantages and shortcomings are also discussed with a number of examples.
Alcohols ; metabolism ; Biocatalysis ; Ketones ; metabolism ; Metabolic Engineering ; NADH, NADPH Oxidoreductases ; metabolism ; Oxidation-Reduction

The aim was to develop the simple preparation method of mogroside ⅢE,and to lay the foundation for the development of the mogroside sweeteners. In the present study,the glycosidase CPU-GH17,which can regio-selectively biosynthesize mogroside ⅢE from mogroside V,was screened from the established library of glycosi-dases. Then,the soluble expression condition of CPU-GH17 in E. coli was exploited by investigating isopropyl β-D-thiogalactoside (IPTG)concentration,culture temperature and induction time,and 0. 4 mmol/L IPTG,15 °C and 12 h was used as optimal condition. The result showed that mogroside V could be completely converted into mogroside ⅢE under the conditions of pH 6. 0,45 °C,3 U/mL enzyme loading,5 mg/mL substrate concentration for 20 h. In conclusion,a biosynthetic system for the regio-selective preparation of mogroside ⅢE by recombinant CPU-GH17 was successfully established and verified at a preparative scale.

Objective To investigate the screening strategy of group B streptococcus (GBS) in the reproductive tract of women in the third trimester and analyze its impact on pregnancy outcome. Methods A total of 85 461 pregnant women in 35-37 weeks of gestation from Bao′an Maternity and Child Health Hospital, Jinan University from January 2011 to June 2018 were enrolled. They were divided into 3 periods according to different GBS screening strategies, the unscreened period included 31 384 cases (36.72%), 33 267 cases (38.93%) were included in partial screening period, 20 810 cases (24.35%) were included in screening period. All GBS screening positive pregnant women were given intrapartum antibiotic prophylaxis (IAP). The impact on pregnancy outcomes, and the impact of different GBS collection transport and culture methods on the positive rate of GBS screening were analyzed. Results (1) The incidence of neonatal early onset GBS disease (EOGBSD) in unscreened period was 0.03% (11/31 773), in partial screening period was 0.02%(6/33 887), and in screening period, the incidence of neonatal EOGBSD decreased to 0, the difference was statistically significant (χ2=7.86, P=0.02).(2) The incidence of hematogenous infection of GBS in pregnant women was 0.02%(6/33 887) in partial screening period, and there was none in screening period, there was no significant difference (adjusted χ2=3.75, P=0.05). (3) In the screening period, the positive rate of GBS was 14.08%(2 719/19 306), which was significantly higher than the positive rate of GBS in the partial screening period (11.48%, 2 058/17 920; χ2=56.12, P=0.00). (4) Antibiotic sensitivity tests of 4 777 GBS strains showed that the antibiotics with higher resistance rate were tetracycline (81.52%, 3 896/4 777), erythromycin (66.59%, 3 181/4 777), and clindamycin (64.31%, 3 072/4 777). The combination of erythromycin, clindamycin and tetracycline was the most common resistant pattern, accounting for 48.80% (2 331/4 777). No penicillin, ceftriaxone or vancomycin resistant strains was found. Conclusions GBS screening strategy in different regions could combine the local neonatal EOGBSD incidence rate, maternal GBS colonization rate, and the socioeconomic factors to determine whether universal GBS screening or screening for high-risk maternal women. GBS screening positive rate is related to the population, scope of the investigation, the sample collection, delivery and culture methods. The multi-drug resistance rate of GBS is high.[Key words] Streptococcus agalactiae; Streptococcal infections; Neonatal sepsis; Prenatal diagnosis; Pregnancy trimester, third; Pregnancy outcome

Mogrosides, the main sweet components isolated from Siraitia grosvenorii, are a family of cucurbitane-type tetracyclic triterpenoid saponins. Given that the high sweetness, low calorie and excellent taste, mogrosides have become the important resource for the development of natural non-nutritive sweeteners. As reported, 11α-hydroxyl group in the structural skeleton of mogrosides was closely related to sweetness and taste, but it had not been confirmed experimentally. In this work, we used mogroside IIIE as a model compound, which was 300 times sweeter than 5% sucrose and tasted better, and modified its 11α-hydroxyl group through glycosyltransferase to elucidate the relations between structure and sweetness of mogroside compounds. The glycosyltransferase HXSW-GT-2 was obtained to regio-selectively glycosylate the 11α-hydroxyl group of mogroside IIIE through the screening of glycosyltransferase library. And then, the soluble expression of HXSW-GT-02 in Escherichia coli was efficiently achieved by optimizing the induction conditions. Subsequently, the yield of glycosylated mogroside IIIE(MG-IIIE-Glu)was increased to > 85% through optimizing reaction pH, temperature, UDP-G dosage and biocatalyst loading. The product MG-IIIE-Glu was bio-prepared at a 0. 5 L scale and the final purity was 97. 8%. A “mouth feel” test showed that MG-IIIE-Glu had no sweetness and displayed obvious bitterness through the comparison with mogroside IIIE and 5% sucrose. In conclusion, the function of the 11α-hydroxyl group of mogrosides in sweetness and taste was preliminarily elucidated which would be beneficial for the structural modification and development of mogroside sweeteners.