Molecular engineering of PETase for efficient PET biodegradation.

The widespread utilization of polyethylene terephthalate (PET) has caused a variety of environmental and health problems. Compared with traditional thermomechanical or chemical PET cycling, the biodegradation of PET may offer a more feasible solution. Though the PETase from Ideonalla sakaiensis (IsPETase) displays interesting PET degrading performance under mild conditions; the relatively low thermal stability of IsPETase limits its practical application. In this study, enzyme-catalysed PET degradation was investigated with the promising IsPETase mutant HotPETase (HP). On this basis, a carbohydrate-binding module from Bacillus anthracis (BaCBM) was fused to the C-terminus of HP to construct the PETase mutant (HLCB) for increased PET degradation. Furthermore, to effectively improve PET accessibility and PET-degrading activity, the truncated outer membrane hybrid protein (FadL) was used to expose PETase and BaCBM on the surface of E. coli (BL21with) to develop regenerable whole-cell biocatalysts (D-HLCB). Results showed that, among the tested small-molecular weight ester compounds (p-nitrophenyl phosphate (pNPP), p-Nitrophenyl acetate (pNPA), 4-Nitrophenyl butyrate (pNPB)), PETase displayed the highest hydrolysing activity against pNPP. HP displayed the highest catalytic activity (1.94 µM(p-NP)/min) at 50 °C and increased longevity at 40 °C. The fused BaCBM could clearly improve the catalytic performance of PETase by increasing the optimal reaction temperature and improving the thermostability. When HLCB was used for PET degradation, the yield of monomeric products (255.7 µM) was ∼25.5 % greater than that obtained after 50 h of HP-catalysed PET degradation. Moreover, the highest yield of monomeric products from the D-HLCB-mediated system reached 1.03 mM. The whole-cell catalyst D-HLCB displayed good reusability and stability and could maintain more than 54.6 % of its initial activity for nine cycles. Finally, molecular docking simulations were utilized to investigate the binding mechanism and the reaction mechanism of HLCB, which may provide theoretical evidence to further increase the PET-degrading activities of PETases through rational design. The proposed strategy and developed variants show potential for achieving complete biodegradation of PET under mild conditions.

Three new flavonoids from the roots of Sophora tonkinensis.

Three new flavonoids including two isoflavanones sophortones A and B (1 and 2), and one chalcone sophortone C (3) were isolated from the roots of Sophora tonkinensis. Their structures were established by UV, IR, HRESIMS, and NMR data. The absolute configurations of 1 and 2 were determined by electronic circular dichroism (ECD) calculations.

Identification and characterization of potential antioxidant components in Isodon amethystoides (Benth.) Hara tea leaves by UPLC-LTQ-Orbitrap-MS.

Isodon amethystoides (Benth.) Hara (IA) tea is a commonly used dietetic Chinese herb and employed for the treatments of tumor and lung abscess. To assess chemical composition and antioxidant capacity of IA leaves extract, a UPLC-LTQ-Orbitrap-MS method and antioxidant tests were used, respectively. 17 compounds were identified including Vinyl caffeate (1), 3,4-dimethoxyphenyl-ß-D-glucopyranoside (2), Rutin (3), Quercetin (4), Loliolide (5), Caffeic acid (6), Rubesanolide D (7), Isorhamnetin (8), Lambertic acid (9), 6, 7-Dehydroroyleanone (10), Dihydrorabdokunmin C (11), Nervosin (12), Quercitrin (13), Vitexin (14), ß-sitosterol (15), Wangzaozin A (16), Amethystonoic acid (17). Among these, 1-14 compounds were novel and have not been reported ever before in IA while component 10 was a novel finding within this genus. Flavonoid components showed better free radical scavenging ability and profound correlation was observed between diterpenoid compounds content and flavonoids activity. Our results provide experimental basis for extraction and separation of chemical constituents of IA which are antioxidant in nature.

Single-port laparoscopy-assisted vaginal repair of a cesarean scar defect: a single-center retrospective study.

BACKGROUND: The incidence of uterine cesarean scar defect (niche) is high, and some patients require surgery. Single-port laparoscopy can reduce post-operative pain, and provide better cosmetic effects. This study was performed to evaluate the safety and superiority of single-port laparoscopy-assisted vaginal repair of uterine cesarean scar defect (niche) in women after cesarean section. METHODS: This study included 74 patients who were diagnosed with uterine cesarean niche at the Shanghai First Maternity and Infant Hospital from January 2013 to June 2015. Thirty-seven patients underwent single-port laparoscopy-assisted vaginal surgery as the case group, and the remaining patients underwent vaginal repair surgery as the control group. We collected data from the inpatient and follow-up medical records. The clinical characteristics of these two groups were compared. The odds ratios and 95% confidential intervals were calculated for each variable by univariate and multivariate analyses. RESULTS: Patients who underwent single-port laparoscopy-assisted vaginal repair had a significantly longer operation time (2.3 [2.0-2.7] vs. 2.0 [1.6-2.3] h, P = 0.015), shorter gas passage time (1.2 [1.0-1.5] vs. 1.7 [1.0-2.0] days, P = 0.012), shorter hospital stay (3.1 [3.0-4.0] vs. 4.5 [4.0-6.0] days, P = 0.019), and fewer complications (0 vs. 4 cases). Univariate analysis showed that depth of the niche (P = 0.021) the mild adhesiolysis score (P = 0.035) and moderate adhesiolysis score (P = 0.013) were associated with the bladder injury. Multivariate analysis showed that the moderate adhesiolysis score (P = 0.029; 95% confidence interval, 1.318-3.526) was the strongest independent predictor of bladder injury. CONCLUSION: This study confirmed the safety and superiority of single-port laparoscopy-assisted vaginal repair of uterine cesarean scars.

Establishment of complete blood count reference intervals for Chinese preschoolers.

BACKGROUND: Reference intervals are critical for interpreting test results of a clinical laboratory. The aim of this study was to establish local reference intervals of complete blood count for healthy preschoolers in China. METHODS: Three thousand eight hundred and twenty-one blood specimens from children aged 4 months to 6 years were collected and analyzed. Complete blood counts were determined by Sysmex XT-4000i Automated Hematology Analyzer. The nonparametric 2.5th to 97.5th percentile reference ranges were calculated according to CLSI EP28-A3c guideline. RESULTS: Reference intervals for each blood cell parameter are determinded as follows: total WBC 4.86-12.1×109 /L for males and 4.73-12.3×109 /L for females; RBC 4.13-5.32×1012 /L for males and 4.08-5.24×1012 /L for females; HGB 109-145 g/L for males and 111-143 g/L for females; HCT 33.1-41.2% for males and 33.3-41.1% for females; MCH 23.5-29.7 pg for males and 24.6-30.0 pg for females; MCHC 320-365 g/L for males and 321-362 g/L for females; MCV 71.4-85.1 fL for males and 73.8-86.9 fL for females; RDW-SD 33.5-41.9 fL for males and 33.5-41.0 fL for females; RDW-CV 12.0-15.2% for males and 11.8-14.5% for females; PLT 181-475×109 /L for males and 179-456×109 /L for females; PCT 0.18-0.44% for males and 0.18-0.43% for females; MPV 8.20-11.6 fL for males and 8.20-11.5 fL for females; PDW 8.40-14.4 fL for males and 8.40-14.0 fL for females; P-LCR 12.0-36.6% for males and 11.8-35.6% for females. CONCLUSIONS: We established local complete blood count reference intervals for apparent healthy preschoolers in China. It is necessary to establishing region-specific reference intervals of complete blood count for preschoolers.

Comparison of the effectiveness of whole-brain radiotherapy plus temozolomide versus whole-brain radiotherapy in treating brain metastases based on a systematic review of randomized controlled trials.

Temozolomide (TMZ) combination with whole-brain radiotherapy (WBRT) has been tested by many randomized controlled trials in the treatment of brain metastases (BMs) in China and other countries. We performed an up-to-date meta-analysis to determine (i) the log odds ratios (LORs) of objective response (ORR) and adverse effects (AEs) for all-grade, and (ii) the T value of mean overall survival in patients with BMs treated with WBRT combined with TMZ versus WBRT alone. PubMed, Chinese National Knowledge Infrastructure, and WanFang Data were searched for articles published up to 28 January 2015. Eligible studies were selected according to the PRISMA statement. ORR, AEs, and 95% confidence intervals were calculated using random-effects models. Eighteen studies were included in our analysis. A total of 1028 participants were enrolled. Summary LORs of ORR were 1.0239 (P<0.0001) on comparing WBRT plus TMZ with WBRT ORR (n=17). The overall mean difference of mean overall survival (n=17) between TMZ plus WBRT and WBRT was 2.2505 weeks (P=0.02185). There was a significant difference between WBRT plus TMZ and WBRT alone with a LOR of AEs for all-grade of (i) 0.923 for gastrointestinal toxicity and (ii) 0.7978 for myelosuppression. Sensitivity analysis and subgroup analysis were also performed. The 18 eligible randomized controlled trials demonstrated that the combination of WBRT and TMZ significantly improves the ORR and is statistically insignificant in prolonging the survival of patients with BMs. In addition, an increase in the incidence of gastrointestinal toxicity and myelosuppression was significant for all-grade.

3, 4-dihydroxyl-phenyl lactic acid restores NADH dehydrogenase 1 α subunit 10 to ameliorate cardiac reperfusion injury.

The present study aimed to detect the role of 3, 4-dihydroxyl-phenyl lactic acid (DLA) during ischemia/reperfusion (I/R) induced myocardial injury with emphasis on the underlying mechanism of DLA antioxidant. Male Spragu-Dawley (SD) rats were subjected to left descending artery occlusion followed by reperfusion. Treatment with DLA ameliorated myocardial structure and function disorder, blunted the impairment of Complex I activity and mitochondrial function after I/R. The results of 2-D fluorescence difference gel electrophoresis revealed that DLA prevented the decrease in NDUFA10 expression, one of the subunits of Complex I. To find the target of DLA, the binding affinity of Sirtuin 1 (SIRT1) to DLA and DLA derivatives with replaced two phenolic hydroxyls was detected using surface plasmon resonance and bilayer interferometry. The results showed that DLA could activate SIRT1 after I/R probably by binding to this protein, depending on phenolic hydroxyl. Moreover, the importance of SIRT1 to DLA effectiveness was confirmed through siRNA transfection in vitro. These results demonstrated that DLA was able to prevent I/R induced decrease in NDUFA10 expression, improve Complex I activity and mitochondrial function, eventually attenuate cardiac structure and function injury after I/R, which was possibly related to its ability of binding to and activating SIRT1.

[Recent advance in the mechanism study of polymeric inhibitors of P-glycoprotein].

P-glycoprotein (P-gp) is an ATP-dependent multidrug efflux pump that acts as a major obstacle for oral drug delivery and cancer therapy. Recent reports have provided evidence that excipients often used in pharmaceutical formulations, such as Pluronic and TPGS, also have inhibitory effects on P-glycoprotein. Because inhibition of efflux transporters by polymeric inhibitors may dramatically increase the bioavailability of P-gp substrates with negligible side effects, identification of the mechanism and their structure activity relationship is therefore of significant importance for pharmaceutical development. Other than competitive inhibition for traditional inhibitors, polymeric inhibitors may modify P-gp function through alterations on membrane fluidity, inhibition of P-gp ATPase, depletion of intracellular ATP and down-regulating of P-gp expression. In the present review, the inhibition mechanism of potential polymeric inhibitors and their structure activity relationship will be discussed along with a brief introduction to the established methodologies.