黄芩苷对大肠埃希菌的抗菌活性及其作用机制

目的探讨黄芩苷对大肠埃希菌的抗菌活性及具可能的作用机制。方法在检测黄芩苷对大肠埃希菌最低抑菌浓度(minimum inhibitory concentration,MIC)及抑菌活力的基础上,进一步检测1倍MIC的黄芩苷对大肠埃希菌胞外乳酸脱氢酶活力、前向散射光及DNA含量的影响。结果黄芩苷对大肠埃希菌的MIC为7 mg/mL,干预2 h时即可达到抑菌活性高峰。1倍MIC的黄芩苷作用大肠埃希菌后,菌液中乳酸脱氢酶活力逐渐上升,8 h时抑菌活力高达(201. 48±19. 06)U/L。1倍MIC的黄芩苷作用大肠埃希菌2 h后,细胞体积缩小、DNA含量减少,与对照组相比,差异均有统计学意义(P <0. 05)。结论黄芩苷通过对大肠埃希菌细胞膜造成损伤而增加其通透性,使菌体物质大量外渗,从而实现其抗菌活性。     

我院2007年至2010年老年尿路感染患者致病细菌及其耐药性研究调查

目的了解我院2007年至2010年老年尿路感染患者致病细菌及其耐药性研究调查情况。方法对我院2007年至2009年的380例老年尿路感染患者取中段尿进行细菌培养。按照全国临床检验中心操作规程鉴定菌种,应用纸片扩散法进行药敏试验,按NCCLS标准判断结果。结果 380例患者尿细菌培养分离出400株细菌,主要为大肠埃希菌,男女感染率间差别有显著性意义(P<0.01)。其中以大肠埃希菌占多数,大肠埃希菌对阿米卡星、头孢由松、亚胺培南的耐药率较低,而对喹诺酮类、头孢噻肟、头袍哌酮、氨苄西林的耐药率较高。结论老年人尿路感染的致病菌主要为大肠埃希菌,男女感染率不同。常呈多重耐药性。抗菌药物的应用应当依据尿培养结果选择敏感药物,合理应用抗生素。     

石墨烯涤纶抗菌性能和抗菌耐洗性研究

通过熔融纺丝方法将石墨烯添加到涤纶中，使涤纶具有抗菌性。选用国标GB/T 20944.3—2008和美国标准AATCC 100—2012分别测试了石墨烯涤纶对大肠埃希菌、白念珠菌、金黄葡萄球菌的抗菌性，确定适合石墨烯涤纶的抗菌测试方法，并测试了石墨烯涤纶的抗菌耐洗性。试验表明：石墨烯涤纶对大肠埃希菌、白念珠菌和金黄葡萄球菌均具有非常好的抗菌效果；石墨烯涤纶经水洗50次以后，仍然对大肠埃希菌、白念珠菌、金黄葡萄球菌保持很好的抑菌率，说明石墨烯涤纶具有良好的抗菌耐洗性；石墨烯涤纶的抗菌测试适合采用GB/T 20944.3—2008振荡法。     

123株产ESBLs大肠埃希菌耐药监测结果分析

目的了解临床常用抗菌药物对我院临床分离产ESBLs大肠埃希菌的体外抗菌活性。方法采用法国梅里埃VITEK-2仪器微量稀释法测定抗菌药物对产ESBLs大肠埃希菌的体外抗菌活性,按CLSI2007版分析结果。结果20种抗菌药物对于所研究产ESBLs大肠埃希菌的敏感率依次为氨苄西林0.8%、哌拉西林0、氨苄西林/舒巴坦4.9%、哌拉西林/三唑巴坦95.1%、头孢唑林0、头孢呋肟0、头孢替坦98.4%、头孢他啶0、头孢曲松0、头孢吡肟0、亚胺培南100%、美罗培南100%、氨曲南0、庆大霉素36.6%、妥布霉素44.7%、阿米卡星95.1%、左旋氧氟沙星18.7%、环丙沙星16.3%、甲氧苄啶/磺胺恶唑28.5%、呋喃妥因82.1%。结论目前碳青霉烯类是对产ESBLs大肠埃希菌最为有效的一类抗菌药物。另外对产ESBLs大肠埃希菌较为有效的药物还有哌拉西林/三唑巴坦、头孢替坦、阿米卡星。     

含载金属离子沸石粉抗菌纸的抗菌性能检测

实验旨在对含载金属离子沸石粉抗菌纸的抗菌性能进行检测。采用液体连续稀释法和96孔板检测法检测载金属离子沸石粉对细菌(大肠埃希菌E.coli、金黄色葡萄球菌S.aureus)和真菌(白色念珠菌M.albican、黑根霉R.nigricans、黑曲霉A.niger)的最小抗菌浓度(MIC),以及平板菌落计数法对抗菌纸的抗菌率进行检测(抗菌率计算公式为:X 5=(A-B)/A×100%,其中X 5为抗菌率,A为对照平板菌落,B为样品平板菌落)。载金属离子沸石粉对大肠埃希菌、金黄色葡萄球菌、白色念珠菌的MIC分别达到1×10~(-7)g/m L、1×10~(-5)g/m L、1×10~(-6)g/m L,对根霉和曲霉也具有一定的抑制效果。抗菌纸对大肠埃希菌、金黄色葡萄球菌、白色念珠菌的抗菌率均在48%以上,完全符合《一次性卫生用品卫生标准》中所规定的抗菌率在26%以上的标准。     

犊牛腹泻大肠埃希菌O-抗原血清型鉴定

目的对犊牛腹泻大肠埃希菌O-抗原血清型进行鉴定。方法收集内蒙古部分地区牛场患犊牛腹泻病的犊牛直肠内容物或粪便共165份,经细菌分离培养、动物致病性试验及16s RNA PCR检测,筛选出致病性大肠埃希菌,并进行O-抗原血清型鉴定。结果分离的大肠埃希菌共165株,115株有致病性,除7株未能确定分型及3株自凝集外,其余105株鉴定为O-抗原血清型。结论大肠埃希菌O-抗原血清型鉴定对流行病学调查及疾病预防均有重要意义。     

肿节风片微生物限度检查法的方法学研究

建立肿节风片的微生物限度检查方法并进行验证,保证检验结果的正确性和可信性.采用平皿菌落计数法对本品的细菌、霉菌及酵母菌计数方法进行验证;采用常规法对大肠埃希菌方法进行验证.通过5种阳性菌的回收率试验,以平板菌落计数法测定肿节风片大肠埃希菌、枯草芽孢杆菌、金黄色葡萄球菌、白色念珠菌、黑曲霉菌回收率皆在84％以上;控制菌测定中,大肠埃希菌可检出试验菌,阴性菌对照组均无生长.本文所确定的方法可作为肿节风片的微生物限度检查方法学验证的依据.     

大肠埃希菌诱导小肠上皮细胞产生β防御素-3的机制

目的探讨大肠埃希菌诱导小肠上皮细胞产生β防御素-3(mouseβ-defensin 3,mBD-3)的机制。方法用大肠埃希菌作用于小肠上皮细胞0、24和48 h后,MTT法检测细胞增殖情况;免疫组化荧光法检测mBD-3的表达;Western blot法检测丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)通路中p-ERK1/2、p-JNK及p-p38的表达。结果大肠埃希菌作用小肠上皮细胞48 h时,细胞生长率最低,为(7. 12±0. 31)%;mBD-3的表达在48 h时最高;p-ERK1/2的表达在48 h时最高,显著高于0和24 h(P 0. 01)。结论大肠埃希菌抑制小肠上皮细胞的增殖,并促进mBD-3的表达,这种促进机制是通过ERK1/2途径实现。     

1H-吲哚亚甲基氨基硫脲席夫碱铜（Ⅱ）配合物及其涂层的抗菌性研究

选用具有生物活性的吲哚-3-甲醛与氨基硫脲制备了席夫碱及其铜（Ⅱ）配合物,通过核磁共振氢谱、红外及紫外光谱等手段鉴定了其结构并确认配合物的配位方式。选用金黄色葡萄球菌（S. aureus）与大肠埃希氏菌（E. coli）测试了席夫碱及其铜（Ⅱ）配合物的抗菌性。结果表明：所制备的铜（Ⅱ）配合物对革兰氏阳性与革兰氏阴性菌均具有较好的抗菌效果,对金黄色葡萄球菌（S. aureus）和大肠埃希氏菌（E. coli）的最小抗菌浓度分别为0.40 g/L和0.95 g/L,具备广谱抗菌性。以吲哚甲醛氨基硫脲席夫碱铜（Ⅱ）配合物作为抗菌剂制备的抗菌涂层同样具有良好的抗菌效果,质量分数为5%时就能够杀灭抗菌涂层上黏附的大肠埃希氏菌（E. coli）。通过电镜观察细菌形貌推测吲哚甲醛氨基硫脲席夫碱铜（Ⅱ）配合物可能通过直接作用于细胞膜将其杀灭,具有较优的抗菌性。     

双壳贝类微生物富集能力及环境水体对其影响分析

为探究不同种双壳贝类的微生物富集能力以及养殖环境水体对贝类微生物富集能力的影响。抽取乐清湾贝类养殖区的三种代表性双壳贝类缢蛏、文蛤和泥蚶,检测其中的大肠埃希氏菌和菌落总数含量。同时抽取嵊泗县贻贝养殖海域内贻贝大肠埃希氏菌和菌落总数以及环境水体中总大肠菌群和细菌总数。三种贝类中,缢蛏的大肠埃希氏菌和菌落总数最高,微生物富集能力最强,泥蚶的微生物富集能力次于缢蛏,文蛤的富集能力最弱;环境水体中总大肠菌群和细菌总数含量越高,贻贝中大肠埃希氏菌和菌落总数含量就越高,呈现一定正相关。     

向日葵茎髓提取物的抑菌活性及机制

以向日葵茎髓为原料,制得3种不同极性向日葵茎髓提取物。采用琼脂扩散法测定3种不同极性向日葵茎髓提取物对4种受试菌的抑菌活性;并以其中的金黄色葡萄球菌和大肠杆菌为研究对象,探讨了乙酸乙酯萃取部位(EE)的抑菌机制。结果显示:不同极性萃取部位对4种受试菌均有一定抑制作用。其中,EE处理金黄色葡萄球菌和大肠杆菌的最低抑菌质量浓度(MIC)均为0.78 g/L,半数抑制质量浓度(IC50)分别为(1.11?0.01)和(1.59?0.03)g/L;抑菌作用与其总酚、总黄酮含量呈显著正相关性(P0.05)。通过SEM分析发现,EE处理引起菌体形态变化,破坏菌体的细胞膜结构;EE可增加金黄色葡萄球菌和大肠杆菌细胞膜结构的通透性,使菌体内的电解质、蛋白质、碱性磷酸酶向胞外泄露;应用4?,6-二脒基-2-苯基吲哚(DAPI)染色和荧光检测发现,EE能干扰细菌遗传物质(DNA)的复制,最终抑制受试菌增殖。     

氧化亚铜微纳米结构的制备及光催化性能研究

以氨基酸为还原剂及配位剂,在碱性溶液中通过水热还原二价铜离子,制备了不同形貌的氧化亚铜微晶。考察了氨基酸对氧化亚铜微晶结构、尺寸、形貌的影响,提出了氧化亚铜微晶在水热条件下的可能形成机理,结果表明氨基酸是良好的形貌调节剂。以亚甲基蓝为探针分子,对所制备的氧化亚铜微晶的光催化性能进行了研究,发现其催化性能与形貌间存在着密切联系。     

Innovative preparation of bacterial cellulose/silver nanocomposite hydrogels: In situ green synthesis,characterization, and antibacterial properties

In this study, an innovative in situ green strategy was applied to prepare bacterial cellulose/silver nanocomposites using green tea as a substrate for the fermentation of Acetobacter xylinum bacteria and a reducing agent for the in situ synthesis of silver nanoparticles. The samples were analyzed by different characterization tests including field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), UV–vis spectroscopy, atomic absorption spectroscopy, and ATR. The results indicated the excellent antibacterial activities with 100% bacterial reduction percentage and inhibition zones of 2.6 and 2.8 cm against S. aureus and E. coli, respectively. Moreover, water absorption percentage and vertical wicking measurements supported the hydrogel properties of the prepared bio-cellulose/silver nanocomposites. Finding of this research suggested the potential of the proposed green route for preparing antibacterial BC which can be regarded as a candidate for future wound healing applications.     

Antibacterial and Cellular Behaviors of Novel Zinc-Doped Hydroxyapatite/Graphene Nanocomposite for Bone Tissue Engineering

Bacteria are one of the significant causes of infection in the body after scaffold implantation. Effective use of nanotechnology to overcome this problem is an exciting and practical solution. Nanoparticles can cause bacterial degradation by the electrostatic interaction with receptors and cell walls. Simultaneously, the incorporation of antibacterial materials such as zinc and graphene in nanoparticles can further enhance bacterial degradation. In the present study, zinc-doped hydroxyapatite/graphene was synthesized and characterized as a nanocomposite material possessing both antibacterial and bioactive properties for bone tissue engineering. After synthesizing the zinc-doped hydroxyapatite nanoparticles using a mechanochemical process, they were composited with reduced graphene oxide. The nanoparticles and nanocomposite samples were extensively investigated by transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Their antibacterial behaviors against Escherichia coli and Staphylococcus aureus were studied. The antibacterial properties of hydroxyapatite nanoparticles were found to be improved more than 2.7 and 3.4 times after zinc doping and further compositing with graphene, respectively. In vitro cell assessment was investigated by a cell viability test and alkaline phosphatase activity using mesenchymal stem cells, and the results showed that hydroxyapatite nanoparticles in the culture medium, in addition to non-toxicity, led to enhanced proliferation of bone marrow stem cells. Furthermore, zinc doping in combination with graphene significantly increased alkaline phosphatase activity and proliferation of mesenchymal stem cells. The antibacterial activity along with cell biocompatibility/bioactivity of zinc-doped hydroxyapatite/graphene nanocomposite are the highly desirable and suitable biological properties for bone tissue engineering successfully achieved in this work.     

Electrochemical preparation of cuprous oxid powder: Part II. Process conditions

Practical electrosynthesis of cuprous oxide powder was carried out on a laboratory scale in a cell specially constructed both with and without a diaphragm under the various operating conditions guided by the authors' previous research. The electrolysis was appraised in terms of the quality of the cuprous oxide product, the electrodissolution of the copper anode, and the SEM microstructure of the cuprous oxide powder. In a cell having a diaphragm, of which nylon fabric is the best, the optimal electrolysis operating conditions are: 250gl^–1 NaCl, 0.1–1.0gl^–1 NaOH, 500–1500Am^–2, 80°C, perforated titanium sheet as the cathode, and around 3% cell volume of electrolyte circulation per minute. Under these conditions a product containing more than 97% cuprous oxide can easily be produced with very stable electrolysis and quite uniform dissolution of the copper anode. To eliminate the use of a diaphragm in the cell, the addition of sodium chromate, sodium dichromate, or calcium gluconate is effective in a sense, depending upon the requirements of the cuprous oxide product. For a product in which more than 95% cuprous oxide and no copper powder are required but a slightly higher content of chloride is allowable, sodium chromate and dichromate can be proposed for use with the former around 0.03–0.05gl^–1 and the latter around 0.020–0.025gl^–1, although the copper anode will not be perfectly evenly dissolved. For a product in which more than 97% cuprous oxide is demanded and a very small amount of copper powder is tolerated, calcium gluconate would be acceptable at around 4.5gl^–1 with quite even dissolution of the copper anode. As to the auxiliary additives, hydrazine hydrate has a negative effect on the quality of the cuprous oxide product. Sucrose can cause a small increase in the chloride content but can make the particles of cuprous oxide more compact thereby increasing sharply its apparent density. Hydroxylamine hydrochloride is the best auxiliary additive which has a positive effect on the purity of the cuprous oxide product but produces no obvious change in the microstructure on the cuprous oxide particles. Even though most work has been concentrated on the electrolytic process, the subsequent processes are equally important: 65–70°C, distilled water for washing, benzotriazole in ethanol solution for stabilization of the cuprous oxide, and 100°C at a vacuum of less than 20mm Hg for drying seem to be satisfactory. A vacuum drying temperature of 55–60°C may be more appropriate to ensure against any oxidation of the product.     

Analysis of the Molecular Structure at the PPS/Copper Interphase and its Role in Adhesion

X-ray photoelectron spectroscopy (XPS) was used to examine the interfacial chemistry in polyphenylene sulfide (PPS)/copper bonded laminates. Several surface pretreatments were studied including a simple methanol wash, two acid etches, thermal oxidation and chemical oxidation. Peel test analysis showed poor adhesion to the methanol-washed and acid-etched foils, giving a peel strength of only 3-5 g/mm. XPS analysis of the failure surfaces revealed a large amount of inorganic sulfide at the interface with reduction of the copper oxide. Chemical oxidation using an alkaline potassium persulfate solution gave a matt-black surface consisting of primarily cupric oxide. These samples showed improved adhesion and XPS analysis of the failure surfaces revealed fracture through a mixed PPS/cuprous oxide layer. A simple thermal oxidation yielded a cuprous oxide surface layer and laminates bonded to these surfaces showed a more than ten-fold increase in peel strength. XPS analysis of the failure surfaces showed much lower amounts of interfacial copper sulfide and it was postulated that excess sulfide at the interface was responsible for the poor adhesion observed for other pretreatments.     

鲎素抗菌肽多效协同抗菌机理的初步研究

为了研究鲎素的抗菌机制,采用紫外吸收法检测细菌与鲎素共同孵育前后大分子泄漏情况;采用透射电镜观察细菌和鲎素共同孵育前后细菌形态和结构的变化;采用紫外吸收法和凝胶电泳技术观察鲎素对细菌基因组DNA和质粒DNA结构的影响.结果表明,经鲎素处理的细菌,胞内生物大分子泄漏显著,细胞壁膜遭到不同程度的破坏;鲎素可与细菌基因组DNA和质粒DNA结合,高浓度鲎素可以使DNA发生断裂,进而使质粒DNA复制和转录功能受到抑制.由此可初步得出结论:鲎素抗菌肽抗菌机理是一种协同作用,包括使细菌细胞膜通透性发生变化、作用细胞质内生物功能物质、结合细胞遗传物质DNA、抑制复制转录等多效的协同的作用机制.     

超细氧化亚铜的制备及在污水处理中的光催化应用

在碱性条件下,葡萄糖和水合肼还原硫酸铜制备了超细氧化亚铜。采用扫描电镜（SEM）和X衍射仪（XRD）进行表征,并在太阳光照条件下用氧化亚铜处理台盼蓝溶液,考察其对污水处理的光催化降解性能。考察了温度、台盼蓝初始浓度、光照时间、催化剂用量对台盼蓝溶液脱色率的影响,结果表明,超细氧化亚铜粒子粒径约为1μm,分散性较好;0.2g氧化亚铜在30℃太阳光照射1.5h条件下,处理50mL（15mg.L-1）的台盼蓝溶液脱色率为98.8%,氧化亚铜在重复使用4次后脱色率为87.8%。     

防污涂料中氧化亚铜的渗出速率及降解行为研究

氧化亚铜(Cu2O)作为在目前海洋防污涂料广泛使用的防污剂,研究其渗出速率和在海洋环境中的降解行为具有重要的意义。介绍了ISO15181铜离子渗出速率测试方法,并研究了不同配方的自抛光型防污涂料的铜离子渗出速率,最后研究了氧化亚铜在海洋环境中的降解行为。结果表明:铜离子渗出速率可通过涂料配方进行调整,氧化亚铜在海洋环境中的最终降解产物是碱式碳酸铜。     

Synthesis and characterization of bacterial cellulose/alginate blend membranes

Bacterial cellulose and alginate in an aqueous NaOH/urea solution were used as substrate materials for the fabrication of a novel blend membrane. The blend solution was cast onto a Teflon plate, coagulated in a 5 wt % CaCl₂ aqueous solution, and then treated with a 1% HCl solution. Supercritical carbon dioxide drying was then applied for the formation of a nanoporous structure. The physical properties and morphology of the regenerated bacterial cellulose and blend membranes were characterized. The blend membrane with 80% bacterial cellulose/20 wt % alginate displayed a homogeneous structure and exhibited a better water adsorption capacity and water vapor transmission rate. However, the tensile strength and elongation at break of the film with a thickness of 0.09 mm slightly decreased to 3.38 MPa and 31.60%, respectively. The average pore size of the blend membrane was 10.60 Å with a 19.50 m²/g surface area. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008