Biofabrication, structure and characterization of an amylopectin-based cyclic glucan

A novel amylopectin-based cyclic architecture was fabricated, arising from microbial branching enzyme treated waxy rice starch. The recombinant enzyme had a molecular weight of 72.0 kDa, and exhibited optimum activity at pH 7.0 and 75 °C. During the cyclization reaction catalyzed by a branching enzyme, the molecular weight of amylopectin rapidly decreased for the initial 2 h, and then very slowly decreased, tapering off at approximately 1.8 × 105 g mol-1 at 12 h. The number of A-chain fractions greatly increased, whereas the percentage of B-chain fractions decreased after enzymatic modification, accompanied by more α-1, 6 linkage formation. The core ring structure as a glucoamylase-resistant fraction had a number-average degree of polymerization of 21, which was constructed by 19 glucose units linked with, 2 glucosyl stubs at the O-6-position of the cyclic glucan through α-1,4 and α-1,6 linkages. Similar to large-ring cyclodextrin with equal glucose units, this cyclic glucan had a cavity geometry with two-circular loops and short stubs in perpendicular planes. Moreover, this cyclic glucan could complex with iodine for the host-guest formation. These results revealed the potential application of the amylopectin-based cyclic glucan as a good delivery system to encapsulate and protect bioactive ingredients.

Synthesis of potential prebiotic α-glucooligosaccharides using microbial glucansucrase and their in vitro fecal fermentation

Novel α-glucooligosaccharides were synthesized by the acceptor reaction of Leuconostoc citreum SK24.002 glucansucrase with maltose and sucrose. The impact of synthesis conditions, including the ratio of sucrose to maltose and the substrate concentration, on the formation of α-glucooligosaccharides was evaluated. Under the optimized experimental conditions, the yield of a mixture of α-glucooligosaccharides with DP 3-5 reached approximately 56.4% with a concentration of 170.7 mg mL-1. Each of these α-glucooligosaccharides was purified, and the structures were assigned as follows: α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP3), α-D-Glcp-(1,3)-α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP4), and α-D-Glcp-(1,6)-α-D-Glcp-(1,3)-α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP5), respectively. For these three structurally different oligosaccharides, the fermentation selectivity by fecal bacteria was determined in anaerobic batch culture. Fructooligosaccharide (FOS) was used as a positive prebiotic control. Similar to FOS, all three α-glucooligosaccharides selectively stimulated the proliferation of Bifidobacteria and Lactobacilli compared with the control. DP3 exhibited the strongest prebiotic ability to increase the Bifidobacterium and Lactobacillus population, whereas DP5 produced the most short-chain fatty acids. In addition, DP4 produced the highest butyrate concentration and resulted in the lowest acetate : propionate ratio. These results suggested that the enzymatically synthesized α-glucooligosaccharides were potential prebiotics, underlining correlations between the structural features of oligosaccharides and their impact on the metabolism of fecal microbiota.

Interaction between soybean protein and tea polyphenols under high pressure

Tea polyphenols (TP) and soybean proteins (SP) are important materials in food industry. High hydrostatic pressure (HHP) is a useful tool for improvement of protein's function. This study evaluated the interactions between the polyphenol and HHP-treated protein using circular dichroism, fluorescence spectroscopy and molecular modeling. The high pressure at 400 MPa significantly modified the secondary structure of SP by increasing the β-sheet content and decreasing the α-helix content, while the addition of 0.1% (w/v) tea ployphenol appeared to protect the α-helix structure. The surface hydrophobicity decreased with HHP treatment and the addition of TP. The optimal solubility of native SP was 0.258 g/mL at 0.08% (w/v) TP. Together with HHP treatment; TP increased the protein solubility to 0.50 g/mL and the emulsifying activity was enhanced approximately three times, up to 43.5%. The micro-texture of SP matrix was also improved with TP and HHP treatment. Both the hydrogen bonding and hydrophobic interaction between TP and SP were elucidated using docking method. Apart from the hydrogen bonding, the Pi-Pi interaction was observed in the binding of phenolic compounds to 7S or 11S globular protein.

[Efficacy and safety of haploidentical hematopoietic stem cell transplantation for 17 patients with paroxysmal nocturnal hemamoglobinuria]

目的

探讨单倍型造血干细胞移植治疗阵发性睡眠性血红蛋白尿症（PNH）的疗效和安全性。

方法

回顾性分析2013年1月至2017年9月采用亲缘单倍型移植治疗的17例PNH患者临床资料。

结果

17例患者中原发PNH 4例，再生障碍性贫血（AA）-PNH综合征13例。所有患者均以改良白消安+环磷酰胺联合抗胸腺细胞球蛋白（ATG）进行清髓性预处理。G-CSF动员的供者骨髓联合外周血干细胞作为移植物来源。环孢素A+吗替麦考酚酯+短程甲氨蝶呤预防移植物抗宿主病（GVHD）。移植后17例患者均获粒系及巨核系造血重建，粒细胞中位植入时间为移植后12（10~15）d，血小板中位植入时间为移植后14（11~45）d。所有患者在+30 d经植入鉴定证实为完全供者嵌合体。7例患者发生Ⅱ~Ⅳ度急性GVHD，4例发生慢性GVHD。中位随访时间为27.1（8.6~60.4）个月，17例患者中15例存活，2例死亡，死因分别为肺部重症感染和移植相关的血栓性微血管病。3年总生存率为（77.8±15.2）%。

结论

对于无完全相合供者的PNH患者，尝试进行单倍型造血干细胞移植有效、安全。

Dietary polyphenols modulate starch digestion and glycaemic level: a review

Polyphenols, as one group of secondary metabolite, are widely distributed in plants and have been reported to show various bioactivities in recent year. Starch digestion not only is related with food industrial applications such as brewing but also plays an important role in postprandial blood glucose level, and therefore insulin resistance. Many studies have shown that dietary phenolic extracts and pure polyphenols can retard starch digestion in vitro, and the retarding effect depends on the phenolic composition and molecular structure. Besides, dietary polyphenols have also been reported to alleviate elevation of blood glucose level after meal, indicating the inhibition of starch digestion in vivo. This review aims to analyze how dietary polyphenols affect starch digestion both in vitro and in vivo. We can conclude that the retarded starch digestion in vitro by polyphenols results from inhibition of key digestive enzymes, including α-amylase and α-glucosidase, as well as from interactions between polyphenols and starch. The alleviation of postprandial hyperglycemia by polyphenols might be caused by both the inhibited starch digestion in vivo and the influenced glucose transport. Therefore, phenolic extracts or pure polyphenols may be alternatives for preventing and treating type II diabetes disease.

[Outcome of combination of HLA-haploidentical hematopoietic SCT with an unrelated cord blood unit for 127 patients with acquired severe aplastic anemia]

目的

评价单倍型造血干细胞移植（haplo-HSCT）联合第三方脐血干细胞移植治疗重型再生障碍性贫血（SAA）的疗效及安全性。

方法

对2011年9月至2017年4月间接受haplo-HSCT联合第三方脐血干细胞移植的127例SAA患者进行回顾性研究。

结果

全部127例SAA患者中，男74例，女53例，中位年龄23.5（3~54）岁，其中极重型再生障碍性贫血65例。诊断至移植中位时间2（0.5~180）个月。单倍型造血干细胞来源为骨髓+外周血。脐血均选用单份，HLA配型≥4/6相合。127例患者均接受改良Bu/Cy+ATG/ALG预处理方案（白消安+环磷酰胺+抗胸腺细胞球蛋白/抗淋巴细胞球蛋白）。以环孢素A、霉酚酸酯联合短程甲氨蝶呤预防GVHD。回输单倍型供者单个核细胞10.87（3.61~24.00）×10⁸/kg，CD34⁺细胞3.49（1.02~8.89）×10⁶/kg；回输脐血单个核细胞2.22（1.10~7.30）×10⁷/kg，CD34⁺细胞0.56（0.16~2.27）×10⁵/kg。127例患者中5例发生早期死亡。在可评估的122例患者中，1例发生原发植入失败，其余121例患者成功植入（均为单倍型造血干细胞植入）。中性粒细胞、血小板植入时间分别为11（9~28）d、15（9~330）d，5例患者发生血小板植入不良。移植过程中74例（58.27%）发生感染。存活患者中位随访20.5（4.0~60.0）个月，Ⅱ~Ⅳ度急性GVHD发生率为24.79%（30/121），中/重度慢性GVHD发生率为14.15%（15/106），预期4年总生存率为（78.5±4.3）%，无失败生存率为（77.4±4.3）%。

结论

haplo-HSCT联合第三方脐血干细胞移植治疗SAA疗效确切且安全性较好，在无全相合供者情况下可作为有价值的治疗选择。

[An experimental study of CD4 targeted chimeric antigen receptor modified T cell with anti-lymphoma activity]

目的

探讨针对CD4膜蛋白的CAR-T细胞对CD4⁺T细胞淋巴瘤细胞的靶向特异性杀伤作用。

方法

采用重组DNA技术构建含4-1BB共刺激分子的第二代针对CD4的CAR慢病毒载体，应用293T细胞包装慢病毒，采用流式细胞术检测T细胞的转染效率及T细胞亚群动态变化，采用流式细胞术微球法检测培养上清中IFN-γ浓度。

结果

①构建的慢病毒载体转染激活的T细胞后CAR膜蛋白阳性率达到50.0%~70.0%。T细胞激活后部分CD8⁺T细胞弱表达（dim）CD4膜蛋白。T细胞转染针对CD4的CAR慢病毒后CD4⁺ T细胞、CD8⁺ CD4^dim T细胞逐渐被清除。②CAR-T细胞、对照组T细胞（空载体转染的T细胞）以8∶1效靶比分别与CD4⁺人T细胞淋巴瘤细胞株KARPAS 299细胞共培养24 h，杀伤效率分别为（96.9±2.1）%和（11.2±3.1）%，前者明显高于后者（t=7.137，P=0.028）。③CAR-T细胞单独培养，与转染慢病毒载体表达人CD4的K562细胞（K562-CD4细胞）、K562细胞共培养后上清中IFN-γ浓度分别为（1 785±268）、（15 648±2 168）、（1 978±354）pg/ml，CAR-T细胞与K562-CD4细胞共培养上清IFN-γ浓度明显高于其他两组，差异有统计学意义（P<0.01）。

结论

CD4特异性CAR-T细胞效应细胞免疫表型为CD8⁺ CD4⁺ T细胞，在体外具有杀伤正常CD4⁺ T细胞和CD4⁺ T细胞淋巴瘤细胞的活性，对于CD4^dim T细胞也有较好的清除活性。

Mechanism of binding interactions between young apple polyphenols and porcine pancreatic α-amylase

The binding interactions between young apple polyphenols and porcine pancreatic α-amylase were investigated through isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC) and molecular docking. The results obtained were compared with those obtained through inhibition kinetics and fluorescence quenching. It was found that binding of tannic acid, chlorogenic acid, caffeic acid and epicatechin with α-amylase is an exothermal process, with the binding constants in the order of tannic acid > chlorogenic acid > caffeic acid > epicatechin. This is consistent with the orders of reciprocal of competitive inhibition constant and fluorescence quenching constant. The binding energy obtained through molecular docking showed the same order, except for epicatechin. These results are consistent with the inhibition of α-amylase being caused by the binding of the polyphenols with the enzyme. In addition, from the fluorescence quenching and DSC data, total polyphenols, tannic acid, chlorogenic acid and caffeic acid were found to partially unfold the enzyme structure.

Improving the properties of starch-based antimicrobial composite films using ZnO-chitosan nanoparticles

This work dealt with the antimicrobial nanoparticles and incorporated them into the modified starch matrix to prepare composite films. The ZnO-chitosan nanoparticles with 57.3 wt% ZnO were sol-gel synthesized for formation of hexagonal phase. The absorption peak and average size of nanoparticles was approximately 364 nm and 25 nm, respectively. It was observed that nanoparticles with less than 3.0 wt% were homogenously dispersed in the starch matrix. The increase of nanoparticles in films resulted in a substantial reduction of water vapor permeability from 51.0% to 43.7% accompanied with an increase of tensile strength from 4.11 to 12.79 MPa (p < 0.05). Moreover, higher addition (4.0-5.0 wt%) resulted in aggregation of nanoparticles in films and increased water vapor permeability (p < 0.05). The antimicrobial activity of starch-based films was positively correlated with the loading level of nanoparticles, and these films had stronger suppression in Gram-positive S. aureus than Gram-negative E. coli.

[Comparison of allogeneic or autologous hematopoietic stem cell transplant for high-risk peripheral T cell lymphomas]

目的

比较自体造血干细胞移植（auto-HSCT）和异基因造血干细胞移植（allo-HSCT）治疗高危外周T细胞淋巴瘤（PTCL）疗效的差异。

方法

回顾性分析苏州大学附属第一医院60例接受HSCT治疗的高危PTCL患者临床资料。

结果

60例PTCL患者均为高危组患者（IPI评分≥3分），接受移植时中位年龄31 (12~58）岁。包括PTCL非特指型22例、ALK阴性的间变大细胞淋巴瘤22例、血管免疫母细胞淋巴瘤16例。其中接受auto-HSCT的有39例（63.5%），接受allo-HSCT的有21例（36.5%）。移植前40例完全缓解（CR），2例部分缓解（PR），18例未缓解（NR）。40例CR患者中10例接受allo-HSCT, 30例接受auto-HSCT。20例PR+NR患者中11例接受allo-HSCT, 9例接受auto-HSCT。移植后中位随访时间为39 (1~96）个月，auto-HSCT和allo-HSCT组的5年无进展生存率分别为61％和60%（P=0.724）。auto-HSCT和allo-HSCT组的5年总生存率分别为62％和61%（P=0.724）。auto-HSCT和allo-HSCT组的5年移植相关死亡率分别为22.7％和41.8%（P=0.250）。截至末次随访时间，auto-HSCT中7例患者复发，allo-HSCT组中2例复发，auto-HSCT和allo-HSCT组的5年累计复发率分别为37.2％和10.1%（P=0.298）。

结论

高危PTCL患者选择auto-HSCT或allo-HSCT治疗长期生存无明显差异，但allo-HSCT组患者移植前多为NR状态，表明对于NR患者，allo-HSCT效果可能较好。

Molecular Dynamics Simulation for Mechanism Elucidation of Food Processing and Safety: State of the Art

Molecular dynamics (MD) simulation is a useful technique to study the interaction between molecules and how they are affected by various processes and processing conditions. This review summarizes the application of MD simulations in food processing and safety, with an emphasis on the effects that emerging nonthermal technologies (for example, high hydrostatic pressure, pulsed electric field) have on the molecular and structural characteristics of foods and biomaterials. The advances and potential projection of MD simulations in the science and engineering aspects of food materials are discussed and focused on research work conducted to study the effects of emerging technologies on food components. It is expected by showing key case studies that it will stir novel developments as a valuable tool to study the effects of emerging food technologies on biomaterials. This review is useful to food researchers and the food industry, as well as researchers and practitioners working on flavor and nutraceutical encapsulations, dietary carbohydrate product developments, modified starches, protein engineering, and other novel food applications.

Thermostability and Specific-Activity Enhancement of an Arginine Deiminase from Enterococcus faecalis SK23.001 via Semirational Design for l-Citrulline Production

l-Citrulline is a nonessential amino acid with a variety of physiological functions and can be enzymatically produced by arginine deiminase (ADI, EC 3.5.3.6). The enzymatic-production approach is of immense interest because of its mild conditions, high yield, low cost, and environmental benignity. However, the major hindrances of l-citrulline industrialization are the poor thermostability and enzyme activity of ADI. Hence, in this work, directed evolution and site-directed mutagenesis aided with in silico screening, including the use of b-factor values and HoTMuSiC, were applied to a previously identified ADI from Enterococcus faecalis SK23.001 ( EfADI), and a triple-site variant R15K-F269Y-G292P was obtained. The triple-site variant displays a 2.5-fold higher specific enzyme activity (333 U mg^-1), a lower K_m value of 6.4 mM, and a 6.1-fold longer half-life ( t_1/2,45°C = 86.7 min) than wild-type EfADI. This work provides a protein-engineering strategy to improve enzyme activity and thermostability, which might be transferrable to other ADIs and enzymes.

Purification and characterization of an intracellular α-l-rhamnosidase from a newly isolated strain, Alternaria alternata SK37.001

A strain, Alternaria alternata SK37.001, which produces an intracellular α-l-rhamnosidase, was newly isolated from citrus orchard soil. The molecular mass of the enzyme was 66 kDa, as evaluated by SDS-PAGE and 135 kDa, as determined by gel filtration, which indicated that the enzyme is a dimer. The enzyme had a specific activity of 21.7 U mg^-1 after step-by-step purification. The optimal pH and temperature were 5.5 and 60 °C, respectively. The enzyme was relatively stable at a pH of 4.0-8.0 and a temperature between 30 and 50 °C compared with other pH levels and temperatures investigated. The enzyme activity was accelerated by Ba²⁺ and Al³⁺ but inhibited by Ni²⁺, Cu²⁺ and Co²⁺, especially Ni²⁺. The kinetic parameters of K_m and V_max were 4.84 mM and 53.1 μmol mg^-1 min^-1, respectively. The α-l-rhamnosidase could hydrolyze quercitrin, naringin and neohesperidin, hesperidin and rutin rhamnose-containing glycosides but could not hydrolyze ginsenoside Rg2 or saiko-saponin C.

[Anti-CD(25) monoclonal antibody as a salvage therapy for steroid-refractory acute graft-versus-host disease in 80 patients receiving allogeneic hematopoietic stem cell transplantation]

Objective: To investigate the efficacy of anti-CD(25) monoclonal antibody for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Methods: A total of 80 patients with SR-aGVHD from January 1st 2012 to December 31st 20l6 were enrolled in this study. Acute GVHD were classified as classic aGVHD (n=72) and late-onset aGVHD (n=8). Anti-CD(25) monoclonal antibodys (mAb) were administrated on days 1, 4, 8, 15, and 22. The efficacy of anti-CD(25) mAb was evaluated at day 28 after the initial treatment. The associated factors of clinical outcome were analyzed. Results: The overall response (OR) rate of anti-CD(25) mAb was 75% (60/80), with complete response (CR) rate, partial response (PR) rate and no response(NR) rate 52.5% (42/80), 22.5% (18/80), and 25% (20/80), respectively. GVHD-relapse was not observed with a median follow-up time of 394.5 days (range, 12-1 761 days). The 6-month overall survival (OS) rate was 68.4%(95%CI 63.2%-73.6%). The 1-year OS rate was 63.1% (95%CI 57.6%-68.6%), and 2-years OS rate was 50.7% (95%CI 44.3%-57.1%). Non-relapse mortality (NRM) rate of 1 and 3 years was 32.6% (95%CI 27.2%-38%) and 41.7% (95%CI 35.3%-48.1%), respectively. The 1 and 2 years cumulative incidence of chronic graft versus host disease (cGVHD) was 32.9% (95%CI 26.4%-39.4%) and 38.9% (95%CI 31.8%-46.0%). By univariate and multivariate analysis, liver involvement was an independent poor risk factor of SR-aGVHD (OR=4.66, 95%CI 1.145-18.962, P=0.032). Conclusion: Anti-CD(25) mAb serves as an alternative and effective salvage therapy for SR-aGVHD at present. Liver involvement is a predictive factor of poor response in patients with SR-aGVHD.

Coupled effects of salt and pressure on catalytic ability of Rhizopus chinensis lipase

BACKGROUND

Both high pressure and environmental factors could influence the catalytic abilities of enzymes. This work investigated coupled effects of pressure and salts on Rhizopus chinensis lipase (RCL) to provide significant information for its further applications.

RESULTS

The maximum activity of RCL was observed under 200 MPa at 40 °C. The highest activity was achieved at concentrations of 0.06-0.1 mol L^-1 for tested salts. The effect of monovalent cations on RCL activity followed the Hofmeister series (K⁺ > Na⁺ > Li⁺ ) at 0.1 MPa but the order of Na⁺ and K⁺ was changed under 200 MPa. Meanwhile, the effects of anions did not follow the Hofmeister series. KCl slightly improved the thermostability of RCL at moderate concentration. At 60 °C, LiCl only stabilised RCL at 0.1 mol L^-1 . The pre-transition unfolding point was shifted from 4.5 to 3.5 mol L^-1 with pressure increasing from 0.1 to 600 MPa. In addition, KCl could not change the lipase's extrinsic fluorescence evolution versus pressure.

CONCLUSION

Pressure and salts could improve catalytic ability and stability of RCL under appropriate conditions. The effect of high pressure on RCL was influenced by salts. Meanwhile salts cannot prevent high pressure-induced damage to RCL. © 2017 Society of Chemical Industry.

[Present situation and influencing factors on classroom mobile phone dependence syndrome in college students]

Objective: To explore the current situation and influencing factors on Classroom Mobile Phone Dependence Syndrome (CMPDS) among college students, and to provide scientific basis for guiding college students to use mobile phones reasonably and healthily. Methods: Stratified cluster sampling method was used. Students from different majors and different grades in Lanzhou University were included as the research objects. Classes were recognized as a unit in receiving basic field investigation in this questionnaire related study. Informed consent principles were followed and process of survey was anonymously carried out. Results: The overall rate of CMPDS in college students was 8.7%, including 'mild rate' as 6.6% and 'seriously mild rate' as 2.1%. No significant differences were found on genders or grades. Factors as shopping in the classroom shopping (OR=3.720), being bored on courses (OR=1.740), WiFi coverage (OR=1.787), time of practice in the classrooms (OR=1.514), and the total time of daily mobile phone use (OR=1.513) etc, appeared as risk factors related to CMPDS among the college students. However. shooting courseware (OR=0.579) appeared as a protective factor. Conclusions: Rate of CMPDS was high in college students and we suggested to form a joint task force among the college authority, teachers and students to work on the related problems. Hopefully, the serious CMPDS condition will be minimized and both physical and mental health of the college students be improved.

Resveratrol and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, comprising ulcerative colitis (UC) and Crohn's disease (CD). Progression of IBD leads to long-term impairment of intestinal structure and function. The pathogenesis of IBD is complex, involving environmental, immunological, genetic, microbial, and psychological factors. The conventional therapies and many existing biopharmaceuticals for IBD have limited efficacy or adverse effects. As a promising safe and effective therapy for IBD, resveratrol has been studied widely, as it has shown anti-inflammatory and antioxidant activity. Resveratrol's mechanism of action involves multiple immune responses and signaling pathways; it is absorbed quickly and metabolized into various derivatives. However, the poor water solubility and low bioavailability of resveratrol limit its clinical applications. Further research should attempt to improve the stability and oral bioavailability of resveratrol by modification and various delivery systems.