Heterologous expression of a novel β-glucosidase BglD2 and its application in polydatin-hydrolyzing / 生物工程学报

A novel β-glucosidase BglD2 with glucose and ethanol tolerant properties was screened and cloned from the deep-sea bacterium Bacillus sp. D1. The application potential of BglD2 toward polydatin-hydrolyzing was also evaluated. BglD2 exhibited the maximal β-glucosidase activity at 45 °C and pH 6.5. BglD2 maintained approximately 50% of its origin activity after incubation at 30 °C and pH 6.5 for 20 h. BglD2 could hydrolyze a variety of substrates containing β (1→3), β (1→4), and β (1→6) bonds. The activity of β-glucosidase was enhanced to 2.0 fold and 2.3 fold by 100 mmol/L glucose and 150 mmol/L xylose, respectively. BglD2 possessed ethanol-stimulated and -tolerant properties. At 30 °C, the activity of BglD2 enhanced to 1.2 fold in the presence of 10% ethanol and even remained 60% in 25% ethanol. BglD2 could hydrolyze polydatin to produce resveratrol. At 35 °C, BglD2 hydrolyzed 86% polydatin after incubation for 2 h. Thus, BglD2 possessed glucose and ethanol tolerant properties and can be used as the potential candidate of catalyst for the production of resveratrol from polydatin.

Clinical efficacy of video-assisted thoracoscopic lobectomy in the treatment of primary lung cancer in elderly patients / 中华老年医学杂志

Objective To evaluate the clinical efficacy of video-assisted thoracoscopic lobectomy in the treatment of primary lung cancer in elderly patients.Methods Clinical data of 50 elderly patients with primary non-small cell lung cancer undergoing lobectomy at our hospital from July 2016 to July 2017 were retrospectively analyzed.The patients were divided into video-assisted thoracoscopic surgery(VATS) group(n =30) and conventional thoracotomy group (n =20).General data of surgery including operating time,intraoperative bleeding volume,the total volume of intraoperative drainage,the group number of lymph node dissection and the number of dissected lymph nodes,and postoperative data including duration of chest tube drainage,the first 24 h post-operative pain numeric rating scale(NRS)score,postoperative hospitalization time and 30-day postoperative complication were analyzed and compared between the two groups.Results All operations were successfully completed in all patients of both groups,and no patient died during the perioperative period.The differences were statistically significant between VATS and traditional thoracotomy groups in operating time[(96.8 ± 10.2)min vs.(126.3±16.1)min,t =6.211,P=0.036],in transoperative bleeding[(101.3±12.7)ml vs.(128.3±14.6)ml,t =4.310,P =0.027]and in total volume of intraoperative draining[(231.7±31.6)ml vs.(295.6 ± 39.8) ml,t =5.610,P =0.018].VATS showed superiority over traditional thoracotomy.In VATS groups vs.the traditional thoracotomy group,the duration of chest tube drainage was[(3.0±0.6)d vs.(3.9±0.8)d,t =5.317,P=0.022],postoperative pain NRS score was [(3.61± 1.09)vs.(5.3 ± 1.3) score,t =6.290,P =0.016]and postoperative hospitalization time was [(5.9 ±1.6) d vs.(8.9 ± 1.9) d,t =3.069,P =0.031].In addition,the incidences of postoperative complications were lower in the VATS group than in the traditional thoracotomy group(1/30 or 3.3 ％ vs.5/20 or 25.0％,x2 =5.335,P=0.021).Conclusions Video-assisted thoracoscopic lobectomy is safe and effective in treating primary lung cancer in elderly patients and can promote postoperative recovery,which is more suitable for elderly patients with primary lung cancer.

Co-expression of β-glucosidase and Vitreoscilla hemoglobin in Escherichia coli / 生物工程学报

In producing recombinant β-glucosidase in Escherichia coli by high-cell density cultivation (HCDC), insufficient soluble oxygen is always a problem. To address it, Vitreoscilla hemoglobin (VHb) was introduced into Escherichia coli by the bicistron and T₇ promoter expression systems, to improve soluble oxygen by bacterial cells and thereby to enhance the biomass and recombinant β-glucosidase production. In the case of bicistron expression system, cell density in shaking flask reached OD₆₀₀=(4.24±0.29), 35.03% higher than that of the control without VHb. Correspondingly, the maximum activity of β-glucosidase co-expressed with VHb was (9.78±0.55) U/mL, 25.38% higher than that of the control. In a 3-L fermentor, the maximum activity of β-glucosidase was 141.23 U/mL, 35.57% higher than that of the control. In contrast, the activity of β-glucosidase co-expressed with VHb under T₇ promoter was lower than that of the control, either in flask or in fermentor. Co-expressing β-glucosidase with VHb using the bicistron expression system may improve the tolerance of E. coli to insufficient soluble oxygen and thus promote the bacterial biomass and the enzyme yield.

Bioinformatic analysis and characterization of myxobacteria laccase-like multicopper oxidases / 生物工程学报

Laccase is a widely-used environment-friendly copper-containing oxidase found in many plants, insects and fungi. Recently, more and more laccases are also found in bacteria. Myxobacteria are an important bacteria resource. However, myxobacteria are much more difficult to isolate and purify than other bacteria. We used bioinformatic approach to screen myxobacteria proteomes available in NCBI. Based on conserved sequences of four copper binding sites in multicopper oxidase, 30 potential laccase sequences were obtained. Among them, nine genes were synthesized and expressed in Escherichia coli BL21 (DE3). Seven proteins showed laccase activity when tested with traditional laccase substrates. One protein, named rSC-2, was chosen for further research because it exhibited the highest activity towards 2,6-dimethyl phenol (DMP). The molecular weight of rSC-2 was 57 kDa. Its specific activity to DMP was 0.27 U/mg. The optimal temperature and the optimal pH were 60 ℃ and 7.0, respectively. About 50% of the original activity was retained after incubation at 60 ℃ and pH 7.0-8.0 for 1 h. Metals showed different effects on rSC-2. rSC-2 activity was enhanced by several metalsat concentration of 1 mmol/L, such as Ca²⁺ and Mn²⁺. With a higher concentration of 5 mmol/L, the activity of rSC-2 was apparently inhibited. This is the first report of bioinformatics screening myxobacteria laccases in combination with expression in E. coli.

Isolation, identification and structural characterization of secondary metabolites from amarine sponge-derived rare actinobacterium Dermacoccus sp. X4 / 生物工程学报

We isolated and identified the symbiotic and adnascent microorganisms from an unidentified sponge collected from 10-meter-deep seawater of the Paracel Islands in China. A total of 16 strains were obtained and identified. Through bacteriostatic activity assay, one of the strains, Dermacoccus sp. X4, was found to effectively inhibit the growth of Staphylococcus aureus. Subsequently, its secondary metabolites were purified by silica gel partition, octadecylsilane (ODS) reverse phase, Sephadex™LH-20 size exclusion, and C18 reverse phase chromatography. Using liquid chromatography, mass spectrometry, and nuclear magnetic resonance, three of the purified compounds were structurally characterized to be one 3-(4-hydroxybenzyl) hexahydropyrrolo [1,2-a]pyrazine-1,4-dione and two indole acid glycerides. This is the first report about indole acid glyceride isolated from microbial secondary metabolites, enriching marine drug candidate resources.

The first paired-exchange kidney transplantation between two couples in China / 中华器官移植杂志

Objective To review the first case of paired-exchange kidney transplantation between two couples in China.Methods In April 2006,two cases of paired-exchange living kidney transplantations were successfully performed.Husband 1 in blood type O received a kidney donated from husband 2 in blood type O,while wife 2 in blood type A received a kidney from wife 1 in blood type A.Results The transplantation was performed smoothly.Renal graft in husband 1 functioned for 21 months,and the recipient died at 9th month due to infection.Graft survival and patient survival in wife 2 were 30 month and 31 month respectively.Conclusion Paired-exchange of living-related kidney donation and transplantation,as an effective pathway to resolve the shortage of organ,could be programmed with cautious medical guideline,ethical consideration and legal framework in China.

Diagnostic and therapeutic strategy of traumatic pulmonary pseudocyst / 中国医师进修杂志

Objective To evaluate the diagnostic and therapeutic strategy of traumatic pulmonary pseudocyst (TPP).Methods Fifteen patients who were diagnosed and treated as TPP between January 2000 and November 2011 were studied retrospectively.Results Nonpenetrating chest trauma was the underlying cause in all cases.A typical sign shown on chest radiograph was a thin-walled cavitary lesion in 9 patients,6 patients accompanied by traumatic wet lung,with or without an air-fluid level.Serial radiological images of CT showed high resolution of the above lesions.Single TPP lesion occurred in 9 patients,and multiple TPP lesions in 6 patients.The size of the lesions was 5 -75 (32 ± 17) mm.The pseudocyst was located in the left lung in 5 patients(33％),located in the right lung in 7 patients (47％),located in bilateral lung in 3 patients (20％).All TPP patients were treated conservatively with no occurrence of complications.Conclusions TPP is an uncommon benign lesion secondary to thoracic trauma.CT scan is an optimal option for diagnosis and evaluation of TPP.Uncomplicated cases can take conservative treatment.For complicated patients,theraneutic strategy should be made individually.

Dye decolorization by bacterial laccase Lac15 / 生物工程学报

We screened for laccase from a marine metagenomic library and obtained a bacterial laccase Lac15 and studied its decolorization ability. Using synthetic azo dyes and anthraquinonic dyes as substrates, we investigated the dye decolorization ability of recombinant Lac15 (rLac15). The purified rLac15 had better decolorization ability towards the azo dyes than the anthraquinonic dyes. When incubated at 45 degrees C and pH 8.5 for 1 h with methylsyringate as the mediator, 20 U/L of rLac15 could decolorize 95% of 100 micromol/L Acid Red 6B (AR-6B), 93% of Reactive Blue 194 (M-2GE), 76% of Reactive Brilliant Orange (K-7R) and 66% of Reactive Blue 171 (KE-R). The decolorization ability of rLac15 decreased with the dye concentration increasing. However, more than 80% of M-2GE and AR-6B were degraded even when the dye concentration was up to 200 micromol/L. At room temperature, rLac51 exhibited significant decolorization ability, with 96% of AR-6B, 86% of M-2GE, 66% of K-7R and 66% of KE-Rdegraded within 24 h at 25 degrees C. rLac15 has the potential of industrial applications.

Prolongation of mouse heart allograft survival by injecting T.gondii soluble tachyzoite antigen / 中华器官移植杂志

Objective To investigate the effects of T. gondii soluble tachyzoite antigen (STAgs) on the survival time of mouse heart allograft and the possible mechanism. Methods The STAgs were prepared by pulverizing T. gondii tachyzoite with ultrasound on ice. Cervical heterotopic heart transplantations were done by using Balb/c mice as donors, and C57BL/6 mice as recipients.The recipients were classified randomly into three groups: syngeneic group, acute rejection group and STAgs-treated group. The recipients in acute rejection group and STAgs-treated group were injected subcutaneously with 0. 1 ml PBS and 0. 1 ml (5 μg) STAgs at the 4th day before transplantation respectively, and those in syngeneic group were not subjected to any treatment. The grafts were observed daily by cervical palpation, and the total cessation of cardiac contraction was defined as the endpoint. The heart allografts were harvested at the 7th day after transplantation for pathological examination and immunohistochemical staining for CD4+ T, CD8+ T. Results The recipients in syngeneic group were all alive at the 100th day after transplantation. The average survival time in acute rejection group and STAgs-treated group was (6.7± 0.5) days and (70.8± 3.5) days,respectively (P＜0.05). HE staining showed that the rejection on the 7th day after transplantation in syngeneic group, acute rejection group and STAgs-treated group was fallen into 0 degree, Ⅲ-Ⅳ degree and 0- Ⅰ degree, respectively. Immunohistochemical staining revealed that the CD4+ T and CD8+T were markedly down-regulated in STAgs-treated group as compared with those in acute rejection group. Conclusion T. gondii STAgs can significantly prolong the survival time of mouse heart allograft and inhibit the rejection probably by changing the ratio of TH1/TH2, or inhibiting the effect of dendritic cells by inducing the lipoxin A4.

Changes of Tim-3 expression In T lymphocytes from different sites in mice heart-transplant recipients / 中华器官移植杂志

Objective To explore the expression level of Tim-3,the marker of activated T_H 1 cells.in T lymphocytes in different sites from recipients with acute rejection.Methods The model of cervical heterotopic heart transplantation was established in mice Two groups were get up:the isograft group(C57BL/6→C57BL/6) and the allograft group (Balb/c→C57BL/6).Lymphocytes were isolated from peripheral blood,spleens,draining lymph nodes and grafts 3 or 6 days after transplantation.The expression of TIM-3 in CD4~+ and CD8~+ T subsets was detected by flow cytometry.Results There was no significant difference in Tim-3~+/CD4~+ and Tim-3~+/CD8~+ ratio in peripheral blood or spleens between two groups.As compared with the isograft group,the proportion of Tirn-3~+/CD4~+ cells was slightly elevated in draining lymph node(P<0.05),but the percentage of Tim-3~+/CD4~+ cells had no significant change between 3 days and 6 days in the allograft group(P>0.05).The expression of Tim-3 in CD4~+ and CD8~+ of graft infiltrating T cells was obviously increased in allograft group(P<0.01),and it was significantly (P<0.01) up-regulated on the 6th day as compared with that on the 3rd day.Conclusion The dynamic changes of Tim-3 expression in T lymphocytes in draining lymph node and graft were correlated with the progresston oi acute rejection in mice.

Characterization of acute renal allograft rejection by human serum proteomic analysis / 华中科技大学学报（医学）（英德文版）

To identify acute renal allograft rejection biomarkers in human serum, two-dimensional differential in-gel electrophoresis (2-D DIGE) and reversed phase high-performance liquid chromatography (RP-HPLC) followed by electrospray ionization mass spectrometry (ESI-MS) were used. Serum samples from renal allograft patients and normal volunteers were divided into three groups: acute rejection (AR), stable renal function (SRF) and normal volunteer (N). Serum samples were firstly processed using Multiple Affinity Removal Column to selectively remove the highest abundance proteins. Differentially expressed proteins were analyzed using 2-D DIGE. These differential protein spots were excised, digested by trypsin, and identified by RP-HPLC-ESI/MS. Twenty-two differentially expressed proteins were identified in serum from AR group. These proteins included complement C9 precursor, apolipoprotein A-IV precursor, vitamin D-binding protein precursor, beta-2-glycoprotein 1 precursor, etc. Vitamin D-binding protein, one of these proteins, was confirmed by ELISA in the independent set of serum samples. In conclusion, the differentially expressed proteins as serum biomarker candidates may provide the basis of acute rejection noninvasive diagnosis. Confirmed vitamin D-binding protein may be one of serum biomarkers of acute rejection. Furthermore, it may provide great insights into understanding the mechanisms and potential treatment strategy of acute rejection.

Cloning and characterization of a beta-glucosidase from marine metagenome / 生物工程学报

In the present study, through a functional strategy, a metagenome library of the marine microbes from the surface water of the South China Sea was screened for beta-glucosidase and six positive clones were obtained. One of these clones, pSB47B2, was subcloned and further analysed in sequence. The result showed that there was an open reading frame for a novel beta-glucosidase, which was nominated as bgl1B. Using pET22b(+) as vector and Escherichia coli BL21(DE3) as host, Bgl1B was overexpressed recombinantly with high yield obtained and substantial enzymatic activity detected. The recombinant protein (rBgllB) was purified by Ni-NTA affinity chromatography and further biochemically characterized. The results indicated that, with pNPG as substrate, the optimum pH and temperature for the hydrolytic activity of rBgl1B were about 6.5 and 40 degrees C respectively. Under the optimum conditions, rBgl1B hydrolyzed pNPG with an activity up to 39.7 U/mg, Km and Vmax being 0.288 mmol/L and 36.9 micromol/min respectively. In addition, rBgl1B could also hydrolyze cellobiose, with a Km of 0.173 mmol/L and a Vmax of 35 micromol/min. However, we did not detect evident hydrolytic activity of rBgl1B to lactose, maltose, sucrose, and CMC. The enzymatic activity of rBgl1B to pNPG was stimulated to certain degrees by low concentration of Ca2+ or Mn2+, whereas it exhibited significant tolerance against high Na+. Distinguished from most of the beta-glucosidases derived from fungi, which display the highest activities under acidic conditions, rBgl1B exhibited relatively higher activity and stability at pH between 7.0 and 9.0.

Galectin-9(Tim-3L)significantly attenuates allogeneic immune response in mice / 中华微生物学和免疫学杂志

Objective To explore the subcellular localization of Galectin-9 and its effect on allogeneic immune response.Methods The plasmid pEGFP-N1 was inserted with Galectin-9 fragment which was amplified from pBKCMV-Galectin-9 by PCR.The recombinant plagmid wag then transfected into CHO cells using JetPEI in vitro.The cells were cultured in G418 selecting mediam to obtain the stably-transfected cells.The transcription and expression of Galectin-9 gene were verified by immunohistochemical staining and RT-PCR.The solid-phase transgenic CHO cells or freshly-cultured supernatant wag added into the mixed lymphocyte response system to detect the inhibitory effect of Galectin-9.Galectin-9 protein wag administered intraperitoneally for 7d consecutively.Results The expression of Galectin-9 wag localized in the cytosol of CHO.The allogeneic mix lymphocyte proliferation was dose-dependently inhibited by the freshly-cultured supernatant from stably-transfected CHO cells.Furthermore,the supernatant from stably-transfected CHO cells dose-dependently inhibited the level of IL-2.The inhibitory effect could be reversed by Tim-3-Fc blocking.Administration of Galectin-9 significantly prolonged the survival of allogeneic cardiac transplants[(22.7±1.2)d vs(7.2±0.4)d)].Conclusion Galectin-9 may be secreted in physical situation to exert its immunomodulatory function on allogeneic immune response.Furthermore.Galectin-9 may be a novel therapeutic drug in transplant medicine.