化学发光磁酶免疫法检测O157:H7大肠埃希菌

通过自行制备的免疫磁珠结合新型发光底物(AMPPD), 改进了化学发光磁酶免疫检测法, 对人工猪肉样品中O157:H7大肠埃希菌进行了检测, 并与人工计数法进行了比较.     

化学发光磁酶免疫法检测O157∶H7大肠埃希菌

O157∶H7大肠埃希菌是一种致病力非常强的微生物.近年来,陆续有其引起食物中毒事件的报道.1996年日本发生O157∶H7大肠埃希菌食物中毒的爆发流行,感染病例逾万人,死亡9例.2001年我国江苏及安徽等地也发生了肠出血性O157∶H7大肠埃希菌所引发的感染性腹泻事件.目前O157∶H7大肠埃希菌实验室常规检测方法为分离培养计数法,此法费时费力,需要几天的时间才能得到检测结果[1,2],缺乏应对突发事件的能力,因此亟需开发快速检测技术.近年来,多种微生物快速检测技术如ELISA法[3]、热解质谱测定法[4]、多聚酶链反应[5]、荧光成像技术[6]、生物发…     

γ-Fe2O3/Ag/TiO2的制备与抗菌性能

采用两步法合成了γ-Fe₂O₃/Ag/TiO₂复合光催化剂, 以大肠埃希氏菌(E. coli)为目标菌, 对数去除率为评价指标评价了催化剂的抗菌性能, 优化了催化剂的最佳制备参数. 通过X射线衍射、 扫描电子显微镜、 X射线光电子能谱和紫外-可见漫反射光谱等手段对催化剂进行了表征. 结果表明, 当Ti/Ag摩尔比为1:0.05, 煅烧时间为3 h, 煅烧温度为350 ℃时, γ-Fe₂O₃/Ag/TiO₂表现出最佳抗菌活性. 复合催化剂具有介孔结构, 比表面积为89.1 m²/g; 光吸收边界达690 nm, 有良好的可见光响应能力; 磁性较强, 在水处理应用中可有效分离和重复使用. 反应条件不受光源限制, 在有/无光照下均具有良好的抗菌活性, 且太阳光辐照下对E. coli的对数去除率可达6.28.     

超声脐动脉S/D值联合胎心率监测对新生儿窒息的临床诊断分析

文章分析了超声脐动脉收缩期末最大血流速度(S)/舒张期末最大血流速度(D)值联合胎心率监测对新生儿窒息的临床诊断价值.选取发生新生儿窒息的98例产妇作为窒息组,新生儿正常的98例产妇作为未窒息组,比较两组胎心率监测情况和脐动脉血流动力学指标阻力指数(RI)、搏动指数(PI)、S/D值.分析胎心率监测和S/D值与阿氏评分...     

微量量热法研究大肠杆菌对粉防己碱和粉防己总生物碱的耐药性

微量量热法研究大肠杆菌对粉防己碱和粉防己总生物碱的耐药性;粉防己碱;粉防己总生物碱;耐药性;大肠杆菌;微量量热法     

A new enzymatic method for determination of E. coli

Inthispaper,arapid,sensitiveandsimpleenzymaticmethodfordetectingtheE.coltcellshasbeenestablished.P-GalactosidaseisakindofendoenzymeexistingintheE.coltcells.Itcanbereleasedfromthecellsbythepore-formingactionofcolicinEI,andcanbedetectedrapidlybyenZymatic..thodl.Colici.,areplasmid-encodedproteins,bindspecificallytoparticularreceptorsontheoutermembraneofsensitivecellsan.dactmainlythroughtwopathways'.Beca.s.theycanformporesinthemembrane,colicinshavebeenwidelyusedastoolstostudythebiologicalandphy…     

基于分子信标实时监测大肠杆菌DNA连接酶催化的DNA连接过程

报道了一种对DNA连接过程进行实时监测的方法,利用分子信标核酸探针作为DNA连接反应的模板和检测探针,实时监测了 E.coli DNA连接酶催化的DNA连接反应,克服了传统的凝胶电泳技术操作复杂、周期长及无法实时监测DNA连接过程的缺点,为核酸连接过程的实时监测和连接酶催化机理的研究提供了更为丰富的信息.在此基础上,发展了一种快速、准确测定 E.coli DNA连接酶的方法,线性响应范围为4.0×10^-6～2.0×10^-4U/μL,检测下限为4.0×10^-6U/μL.     

大肠杆菌DNA和RNA中核苷的高效液相色谱分析

建立了用反相高效液相色谱法（RP-HPLC）测定大肠杆菌（E.coli）脱氧核糖核酸（DNA）和核糖核酸（RNA）水解产物中核苷的方法，色谱柱为Supelco Inc.c18反相柱，254nm和280nm紫外吸收波长同时检测，分析条件经选择在流速为1mL/min，流动相A（2.5%甲醇 0.01mol/L KH2PO4,PH4.6)28min，流动相B（8.0%甲醇 0.01mol/L KH2PO4，PH4.6)37min，柱温为20℃条件下65min可实现核苷的完全分离，回收率为80.19%-99.31%，相对标准偏差RSD为0.86%-2.62%，该方法具有高灵敏度、高选择性的特点，得到的结果与十分满意。     

Effects of copper on dielectric properties of E. coli cells

Dielectric properties of E. coli cells before and after Cu²⁺ incubation were investigated by using the dielectric spectroscopic technique. The dielectric spectra are analyzed theoretically by means of the extended three-shell ellipsoidal model, which can reflect the complicated morphological structure of E. coli cell including the outer membrane, the periplasmic space, the inner membrane and the cytoplasm. The results showed that dielectric properties of these cellular components were changed with Cu²⁺ treatment in a time- and concentration-dependent way. The permttivity of the outer membrane increased with the incubation time and concentration of Cu²⁺, possibly because polarizability of the outer leaflet of lipopolysaccharides was affected by Cu²⁺. The conductivity of the periplasmic space decreased with the incubation time and concentration of Cu²⁺, possibly due to the damage of peptidoglycan. The decreased permittivity of the inner membrane may be caused by disturbance of the lipid bilayer structure produced by Cu²⁺ incubation. The decreased cytoplasmic conductivity may be the consequence of the leakage of K⁺ from it. The cytoplasmic permittivity decreased with Cu²⁺ treatment probably because of the leakage of its some components.     

新型金属卟啉的合成及其对大肠杆菌生长代谢的抑制作用

以5,10,15,20-四（对羟基苯基）卟啉（2）为原料,合成并表征了一系列 水溶性和非水溶性的金属卟啉。使用LKB 2277热活性监测器测定了大肠杆菌在金属 卟啉4a ～ 4f和7a ～ 7f作用下的生热曲线,得到了不同金属卟啉在不同浓度下大 肠杆菌生长代谢的生热速率常数k,最大发热功率p_(max)和最大发热功率的出现时 间t。结果发现,含有吡啶溴化盐的水溶性金属卟啉7a ～ 7f对大肠杆菌生长代谢 的抑制活性要明显大于含有酯基的金属卟啉4a ～ 4f。     

微量热法测定Vitex negundo Linn对大肠杆菌抑制作用的活性部位

开发药用植物首先必须确定其活性部位. 我们采用微量热法鉴定了一种植物Vitex negundo Linn的四种不同提取物: 正己烷提取物、氯仿提取物、乙酸乙酯提取物和甲醇提取物对大肠杆菌(E. coli)的抑制作用. 结果表明甲醇提取物对大肠杆菌生长的代谢热谱抑制作用最强. 通过计算该提取物作用下大肠杆菌的生长速率常数, 表明该提取物的抑制作用随浓度的升高而增强.     

微量热法研究头孢菌素对大肠杆菌微生物活性的影响

用微量热法测定了两种头孢菌素头孢哌酮钠(CFZ)和头孢哌酮钠舒巴坦钠(CFZ-SBT)在37 ℃时对大肠杆菌DH5α代谢作用的影响. 根据产热曲线分别获得了大肠杆菌DH5α在不同浓度的头孢哌酮钠和头孢哌酮钠舒巴坦钠作用下的生长速率常数(k)、抑制率(I)、最大产热功率(Pm)以及最大产热功率所对应的时间tm等热动力学参数. 研究结果表明, 头孢哌酮钠和头孢哌酮钠舒巴坦钠对大肠杆菌的致死量分别为0.1和0.25 μg/mL. 通过研究k, I, Pm, tm和浓度(c)间的关系发现, 舒巴坦钠的加入没有增加头孢哌酮钠对大肠杆菌DH5α的抑制作用.     

Investigation of the Effect of Four Organic Acids in Radix Isatidis on E. coli Growth by Microcalorimetry

The inhibitory effects of four organic acids (OAs) in Radix Isatidis, a traditional Chinese medicinal herb, on Escherichia coli (E. coli) growth were investigated by microcalorimetry. The power‐time curves of E. coli growth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k₁, k₂), half inhibitory ratio (IC₅₀), maximum heat output (P_max) and peak time (t_p). The values of k₁ and k₂ of E. coli growth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover, P_max was reduced and the value of t_p increased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC₅₀ of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring.     

微流控芯片上大肠杆菌的电化学阻抗检测方法研究

基于细菌悬浮液的阻抗特性和微流控芯片电化学阻抗检测技术,采用所构建的微流控芯片电化学阻抗分析系统,以大肠杆菌为样本,优化了扰动振幅、缓冲溶液电导率、扫描频率和新制大肠杆菌标本静置时间等参数,对大肠杆菌标本、大肠杆菌标准合成样本进行电化学阻抗检测,建立了一种大肠杆菌快速定量检测方法.在扰动振幅500 mV、缓冲溶液电导率...