不同细菌及酵母菌对阴道毛滴虫体外生长的影响

目的研究大肠埃希菌J20、保加利亚乳杆菌、金黄葡萄球菌及AH109酵母菌体外对阴道毛滴虫生长的影响。方法分别将不同浓度(104、105、106和107个/ml)的大肠埃希菌J20、保加利亚乳杆菌、金黄葡萄球菌及AH109酵母菌与阴道毛滴虫进行体外共培养,并对不同培养时间(2、4、6和8 h)的虫体进行计数。结果与空白对照组相比,大肠埃希菌J20及金黄葡萄球菌在低浓度(104个/ml)时即明显影响阴道毛滴虫体外生长(P均0.01),在6 h时即可见白色死亡虫体沉淀:保加利亚乳杆菌仅在高浓度(106和107个/ml)时对阴道毛滴虫的生长有明显影响(P均0.01):AH109酵母菌在不同浓度及不同培养时间对阴道毛滴虫的生长均无明显影响(P0.05)。结论大肠埃希菌J20、金黄葡萄球菌及高浓度(106和107个/ml)保加利亚乳杆菌对阴道毛滴虫生长影响显著,而AH109酵母菌无明显影响,为进一步研究阴道毛滴虫感染后,在体内与阴道菌群的相互作用关系奠定了理论基础。     

VC发酵大菌不同组分对小菌生长及产酸的影响

在VC的二步混菌发酵中,作为伴生菌,巨大芽孢杆菌(大菌)对酮古龙酸杆菌(小菌)的生长和产酸有促进作用.通过比较大菌培养液不同分子量的组分对小菌的促进作用,发现分子量小于1 000的组分对小菌的促进作用最明显.     

修复肠黏膜芽孢杆菌制剂的制备及其对断奶仔鼠生长性能的影响

目的制备具有肠黏膜修复功能的芽孢杆菌制剂,并探讨其对断奶仔鼠生长性能的影响。方法正交试验法优化芽孢杆菌固体发酵原料配比。确定不同发酵时间对嗜热芽孢杆菌活菌数的影响,应用均匀设计试验优化发酵条件。采用最佳发酵原料配比、发酵时间及发酵条件进行3次发酵验证试验,同时检测芽孢杆菌制剂对断奶仔鼠生长性能的影响。结果最佳发酵原料配比为:米糠57.45%,玉米面7.5%,豆粕7.5%,DDGS 22.5%,稻壳5%,硫酸锰0.05%。最佳发酵条件为:温度37℃,底物厚度31 cm,发酵初始p H 7.5,菌液量6%,料水比1.2∶1,发酵时间72 h。验证试验结果表明,嗜热芽孢杆菌固体发酵的活菌数稳定在2.5×10~(11)cfu/g。在仔鼠日粮添加1%芽孢杆菌制剂可显著提高断奶仔鼠3周的体重和日增重(P0.05)。结论成功制备了具有肠黏膜修复功能的芽孢杆菌制剂,日粮中添加1%芽孢杆菌制剂对幼龄动物具有促生长的作用。     

Preparation,physicochemical properties and biocompatibility of biodegradable poly(ether-ester-urethane) and chitosan oligosaccharide composites

In the paper, novel composites of biodegradable poly(ether-ester-urethane) (PEEU) and water-soluble chitosan oligosaccharide (CHO) were prepared using a simple physical mixing method and their potential application as biomaterials was assessed. The PEEU and CHO were dissolved in N,N-dimethylformamide to get a homogenous solution, then the composite films were obtained by the solvent evaporation method. The composites were characterized by FT-IR, and the influence of CHO content on the physicochemical properties of the composite films, including thermal properties, surface morphologies, mechanical properties, surface and bulk hydrophilicity, and in vitro biodegradability, were researched. The thermal stability studies indicated that the composite films had lower initial decomposition temperature and higher maximum decomposition temperature than PEEU film. Only one broad endothermic peak found in DSC curves demonstrated the high compatibility of CHO with PEEU. The ultimate stress and elongation at break of composite films decreased with the increment of CHO content, and the CHO content in the composites should be controlled no more than 25 wt% in order to maintain the mechanical properties (ultimate stress: 18.5 MPa; elongation at break: 890%) to meet the requirement of implant materials. The surface morphologies of composite films were observed by cold field emission scanning electron microscope (FE-SEM), and the results indicated that the homogeneous-dispersed composites could be obtained with CHO content being less than 20 wt%. The results of water contact angle and water absorption showed that the surface and bulk hydrophilicity were closely related with the water-solubility of CHO component. In vitro degradation studies showed that the degradation rate increased with the increasing content of CHO in composites, indicating that the degradation rate of composite films could be controlled by adjusting CHO content. The surface blood compatibility of the composite films was examined by bovine serum albumin adsorption and platelet adhesion tests. It was found that composite films had improved resistance to protein adsorption and possessed excellent resistance to platelet adhesion.     

香根草精油微胶囊的制备及其体外抗炎作用

以明胶和壳聚糖为壁层材料,以香根草精油为囊芯,采用复凝聚法制备香根草精油微胶囊。通过单因素和正交实验筛选微胶囊最佳制备工艺,采用SEM、粒度仪、Zeta电位仪和FTIR对样品进行了表征。测定微胶囊于pH 1.5和7.4时香根草精油的释放率,观察微胶囊对小鼠RAW 264.7细胞的体外抗炎作用。结果表明,香根草精油用量0.3 g,壁材用量1.0 g(其中明胶与壳聚糖的质量比为30∶2)时,封装率可达90.96%;制备的微胶囊表面呈球形,微胶囊粒径为2.303μm,电位–33.8 mV,具有良好的稳定性,封装效果好;该微胶囊于pH 7.4下释放度较佳,72 h内累积释放达87.49%;细胞实验表明,该微胶囊(质量浓度为60、90、120 mg/L)安全无毒,能有效抑制RAW 264.7细胞白介素-1β(IL-1β)、白介素-6(IL-6)和肿瘤坏死因子α(TNF-α)的分泌。香根草精油微胶囊处方工艺简单,质量稳定,抗炎活性良好。     

4-羟甲基-2(5H)-呋喃酮的合成及对铜绿假单胞菌生物膜的影响

对天然化合物4-羟甲基-2(5H)-呋喃酮的合成路线进行了改进,采用三羟甲基氨基甲烷盐酸盐为起始原料,经二羟基保护、氧化成酮,再与乙酸乙酯基三苯基膦叶立德反应,脱保护成内酯环合成出4-羟甲基-2(5H)-呋喃酮,总产率为23%。考察了其对铜绿假单胞菌生物膜的影响,结果显示该化合物对细菌生物膜的形成有一定的抑制作用。     

Preparation and characterization of amidated graphene oxide and its effect on the performance of poly(lactic acid)

An improved Hummers method was used to prepare graphene oxide (GO). Then, the orthogonal experiment design methods were used to select the optimum conditions of the preparation for amidated graphene oxide (AGO) via amidation. The optimum scheme was followed by: reaction temperature 70 °C, reaction time 5 h and GO: benzohydrazide of 1:3 (g:g). The structure of AGO was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscope (TEM) techniques, which demonstrated that the amidation of GO was successful. Furthermore, poly(lactic acid) (PLA)/AGO nanocomposites were prepared by melt blending to improve the comprehensive performance of PLA. Mechanical properties, thermal stabilities, crystallization properties, and rheological behavior of PLA/AGO nanocomposites were investigated, which showed that the addition of 0.3 wt % of AGO increased the tensile strength, elongation-at-break, and impact strength of PLA/AGO nanocomposites by 7.68, 47.32 and 41.27%, respectively, compared with neat PLA. Scanning electron microscopy analysis showed ductile fracture of the PLA/AGO nanocomposites. TEM analysis showed that nano-AGO single layers were evenly dispersed in the PLA matrix, confirming the formation of an exfoliated nanocomposite structure. Differential scanning calorimetry demonstrated that AGO eliminated the cold crystallization of PLA matrix and improved the crystallinity of PLA by 34.1%. In all, this study provided an effective and feasible method for improving the comprehensive performance of PLA.     

肠道病毒71型多克隆抗体F(ab’)2片段的制备及其体外中和效果评价

目的制备肠道病毒71型(enterovirus 71,EV71)多克隆抗体F(ab’)2片段,并评价其体外中和效果。方法采用硫酸铵分级沉淀法从EV71感染的兔血清中提取Ig G,用胃蛋白酶进行酶解,正交试验确定最佳酶解条件;使用阴离子交换层析(Q Sepharose Fast Flow)纯化得到F(ab’)2片段,采用体外中和试验检测其对EV71的中和效果。结果硫酸铵分级沉淀法得到电泳纯的Ig G;最佳酶解条件为:胃蛋白酶与Ig G按1∶10的质量比混合,47℃反应4 h,在此条件下,F(ab’)2的产率最大值为79.51%,且方差分析表明,酶切比例对F(ab’)2产率的影响最大,温度次之,时间对F(ab’)2产率的影响不明显;经阴离子交换层析纯化,可有效去除Fc片段,得到电泳纯的F(ab’)2;F(ab’)2具有与Ig G、正常血清同等的中和效果。结论成功制备了EV71兔多克隆抗体F(ab’)2片段,初步确定该F(ab’)2片段具有良好的体外中和效果。     

Assessment of a new synbiotic preparation in healthy volunteers: survival,persistence of probiotic strains and its effect on the indigenous flora

Background  

Use of synbiotic preparations as dietary supplement is believed to be a valid approach to restore and maintain colonic microflora. However, only few papers have been published on the assessment of these food supplements and none of them have used molecular biology techniques to evaluate the effects of the probiotic components.     

Preparation of monodisperse poly(methyl methacrylate) microspheres: effect of reaction parameters on particle formation, and optical performances of its diffusive agent application

A 3.84 um monodisperse poly(methyl methacrylate) (PMMA) microsphere was prepared by dispersion polymerization in methanol (MeOH)/water (H₂O) media. 2,2′-azobis(isobutyronitrile) (AIBN) and poly(acrylic acid) (PAA) were utilized as initiator and steric stabilizer, respectively. The effects of the PAA stabilizer, AIBN initiator, H₂O solvent and MMA monomer on PMMA particle size and size distribution were reviewed in the first section. The optical properties including total transmittance (T%) and transmittance haze (H%) were performed when the monodisperse PMMA microsphere was applied as a diffusive agent. The result was examined in terms of total interface area in system, and to compare with the performance of three polystyrene (PSt) microspheres with 1.10 um, 3.13 um and 5.21 um in diameter under the same condition.     

重组瑞替普酶包涵体制备及其体外复性

将携带重组瑞替普酶(reteplase, rt-PA)的质粒成功转化到大肠杆菌BL21(DE3)后,诱导表达获得包涵体,考察了诱导剂浓度、培养温度和培养时间等条件对目标蛋白表达量的影响。在此基础上,对高效表达的rt-PA包涵体体外复性过程进行了详细研究。首先利用单因素实验考察了复性液pH、GSH浓度、GSH/GSSG比例、蛋白浓度等各种复性条件对复性效果的影响;并结合正交实验设计,进一步研究了高蛋白浓度下复性后rt-PA酶活变化情况。以0.2 mmol·L^-1 IPTG诱导,在33℃下培养6 h,每升发酵液约可获得1.7 g粗制包涵体。适宜的复性条件为蛋白浓度50 mg·ml^-1,pH 10.0,GSH浓度1 mmol·L^-1,GSH/GSSG比例8,复性收率为87.2%。影响高蛋白浓度下rt-PA复性的关键因素为复性液初始pH及GSH浓度,在800 mg·ml^-1蛋白浓度下复性后rt-PA比活可达7.54×10⁴ IU·mg^-1,荧光光谱分析结果表明复性后rt-PA恢复了其天然态结构。     

Preparation,structure-property relationships of zinc oxide pillared organic layered double hydroxides and its effect on the performance of poly (lactic acid)

Zinc oxide pillared organic layered double hydroxides (ZnO-LDHs-S) were synthesized with sodium dodecyl sulfate (SDS) via a intercalation method. Meanwhile, the properties of ultraviolet (UV) absorbance and antibacterial of ZnO-LDHs-S were investigated. To improve the performances of poly (lactic acid) (PLA), PLA/ZnO-LDHs-S nanocomposites were prepared by melt blending using ZnO-LDHs-S as nucleating agent. Structure and properties of PLA/ZnO-LDHs-S nanocomposites were investigated by Fourier transform infrared spectra, transmission electron microscopy, mechanical properties testing, differential scanning calorimetry, polarized optical microscopy and rheological analysis. It was shown that the introduction of ZnO-LDHs-S improved the comprehensive performance of PLA.