基于碳量子点/羧基化石墨相氮化碳复合材料的电化学发光适体传感器检测牛奶中林可霉素

目的 构建一种高灵敏的核酸电化学发光(electrochemiluminescence,ECL)适体传感器检测牛奶中的林可霉素(lincomycin, LIN)残留。方法 以壳聚糖为交联剂,在玻碳电极(glassy carbon electrode, GCE)表面固定羧基化石墨相氮化碳(carboxylated functionalized graphite-like carbon nitride,C-g-C₃N₄)和碳量子点(carbon quantum dots,CQDs),制得CQDs/C-g-C₃N₄/GCE。电极活化后,将LIN的适配体(Apt-DNA)和二茂铁标记的DNA (Fc-DNA)修饰至电极表面,构建新型的电化学发光适体传感界面。采用循环伏安和交流阻抗对传感器的构建过程及电化学性能进行考察,同时对传感器的电化学发光行为进行分析,并应用于牛奶中LIN的检测。结果 CQDs和C-g-C₃N₄之间能产生强烈的协同效应,复合材料不仅能提供大量的...     

用支撑液膜法构建三相体系提取洁霉素

摘要：运用支撑液膜技术建立了进料相、膜相、反萃取相三相体系,实现了对洁霉素的分离提纯。该体系采用了洁霉素+异构烷烃（Isopar L）+HCl的反应体系,验证了进料浓度（Cb f）、进料相溶液pH、反萃取相溶液pH、萃取剂组成等因素对分配系数（D）的影响。同时,优化了膜组件实现萃取实验的操作条件,根据传质过程建立了数学模型。结果显示：当洁霉素进料浓度Cb f为11.9mmol/L、Isopar L体积分数VF为80%、进料相pH为10.1、反萃取相pH为1.2时,分配系数D最大为2.34。确定膜组件操作条件为：管程流量Vf=520mL/min,壳程流量Vs=500mL/min。根据所建的数学建模分析了各部分传质阻力,其中管程传质阻力为6.7×105s/m,壳程传质阻力为3.7×105s/m,跨膜传质阻力为2.7×106s/m,跨膜传质阻力为主要的传质阻力。     

A sensitive and specific enzyme‐linked immunosorbent assay for the detection of lincomycin in food samples

BACKGROUND: Lincomycin (LIN) is an antibiotic widely used in veterinary medicine to cure infections caused by Gram‐positive pathogens. Although the toxicity of LIN is not serious, it will cause adverse effects in humans, such as pseudomembranous enteritis and bacterial resistance. In this study, for the preparation of a LIN derivative, a novel modification method was adopted. The LIN derivative modified at 2‐position with a carboxylic group at the end of the spacer was synthesised and coupled to carrier proteins. A LIN polyclonal antibody‐based enzyme‐linked immunosorbent assay (ELISA) was developed and characterised. RESULTS: The ELISA standard curve was constructed with concentrations of 0.1–1000 ng mL^?1. The IC₅₀ value for nine standard curves was in the range 23.7–29.3 ng mL^?1 and the limit of detection at a signal‐to‐noise ratio of 3 was 0.15–0.98 ng mL^?1. The cross‐reactivity value of the LIN antibody with clindamycin hydrochloride, a homologue of LIN with similar molecular structure, was 18.9%, while less than 0.1% cross‐reactivity was found with seven other compounds. For LIN‐spiked food samples, the recoveries and relative standard deviation (RSD) were 76.6–117.6% and 1.7–34.6%, respectively. CONCLUSION: The proposed ELISA can be utilised as a sensitive and specific analytical tool for the detection of LIN in food samples. Copyright © 2010 Society of Chemical Industry     

液相色谱-串联质谱法同时测定蜂蜜中的林可霉素、甲硝唑和氯霉素

目的建立液相色谱-串联质谱法同时检测蜂蜜中林可霉素、甲硝唑和氯霉素含量的分析方法。方法蜂蜜样品加水溶解后,过聚合物基质反相固相萃取柱净化,经5%甲醇水溶液淋洗小柱,再用70%甲醇水溶液洗脱目标化合物。采用0.1%甲酸水溶液和乙腈作为液相色谱流动相进行梯度洗脱。经多反应监测模式,在正离子电离模式下测定甲硝唑和林可霉素,在负离子电离模式下测定氯霉素。同位素稀释内标法定量。结果本方法在10 min内通过质谱正负离子电离模式切换对林可霉素、甲硝唑和氯霉素进行同时测定。3个目标化合物在0.25、5和25μg/kg添加水平的回收率为91.0%～107.1%,相对标准偏差小于11.9%(n=6),林可霉素、甲硝唑和氯霉素的方法定量限分别为0.20、0.14和0.20μg/kg。结论本方法易于操作,灵敏度和重现性良好,适用于监督抽检和风险监测等大批量检测工作。     

Molecularly imprinted polymer microspheres prepared via the two-step swelling polymerization for the separation of lincomycin

A molecularly imprinted polymer (MIP) was synthesized via a two-step swelling polymerization method for the purification of lincomycin. Polystyrene microspheres were prepared by the dispersion-polymerization process and used as the substrate. Methacrylic acid was used as the functional monomer, whereas ethylene glycol dimethacrylate was the cross-linker. The MIP was structurally characterized and examined for its separation performance at different conditions (temperature, solvents, etc.). It was found that the MIP possesses the good sphericity, porosity, monodispersity, and a high adsorption capacity of (180 μmol/g) in chloroform solution. Comparison studies showed that the MIP presents a higher capacity than the NIP (non-imprinted polymer) in chloroform solution and a much higher capacity in the practical lincomycin fermentation solution extracts, confirming the underlining mechanisms of the MIP. Scatchard plot revealed two adsorption mechanisms on the MIP, whereas the isotherm is better described by Freundlich equation. The adsorption/elution kinetics demonstrated that the MIP possesses good elution/regeneration capabilities with the elution ratio > 93%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47938.     

零价铁和生物填料强化洁霉素废水水解酸化的研究

考察了零价铁和生物填料的投加对洁霉素废水水解酸化处理效果的强化作用,试验在3个平行的反应器中进行:投加零价铁的反应器(R1)、投加生物填料的反应器(R2)以及普通反应器(R0)。结果表明:在稳定运行时期,R1和R2的COD去除率、酸化率和出水B/C均明显高于R0。零价铁和生物填料的投加都对水解酸化起到了强化作用,提高了废水的可生化性,同时也都提高了反应器抗水质冲击负荷的能力。     

林可霉素工业生产发酵工艺优化

为了提高林可霉素工业生产发酵效价,该研究对林可霉素发酵工艺进行了优化。结果表明,林可霉素最佳发酵条件为二级种子罐发酵培养基中淀粉和黄豆饼粉添加量分别为0.97%和1.43%、延长二级种子移种菌龄至48 h及四级发酵罐基础料计料体积为8 m3。在此优化发酵工艺条件下,林可霉素发酵四级放罐效价高达7 505 U/mL,比原始工艺四级放罐效价提高了16%。初步优化了林可霉素工业生产发酵工艺,提高了林可霉素发酵效能和产量。     

An Efficient Intergeneric Conjugation of DNA from Escherichia coli to Mycelia of the Lincomycin-Producer Streptomyces lincolnensis

Streptomyces lincolnensis is a producer of lincomycin, which is a lincosamide antibiotic for the treatment of infective diseases caused by Gram-positive bacteria. S. lincolnensis is refractory to introducing plasmid DNA into cells because of resistance of foreign DNAs and poor sporulation. In this study, a simple and efficient method of transferring plasmids into S. lincolnensis through the intergeneric Escherichia coli-mycelia conjugation was established and optimized for the first time. The recipient mycelia of S. lincolnensis were prepared in liquid SM medium containing 10.3% sucrose for three days. The dispersed mycelia were conjugated with competent E. coli donor cells. The exconjugants were regenerated efficiently on solid mannitol soya flour (MS) medium containing 20 mM MgCl(2). The average conjugation frequency was observed at 1.1 × 10(-4) per input donor cell and validated functionally by transferring two types of vectors containing lincomycin resistance genes lmrA, lmrB and lmrC into S. lincolnensis mycelia. The data of fermentation in shaking flasks showed the lincomycin yield of the exconjugants increased by 52.9% for the multiple copy vector and 38.3% for the integrative one, compared with the parental strain. The efficient and convenient method of intergeneric E. coli-mycelia conjugation in this study provides a promising procedure to introduce plasmid DNA into other refractory streptomycetes.     

添加氧载体促进林可霉素发酵过程的研究

为了有效的改善林可霉素发酵液中的氧传递速率,研究了氧载体对林可霉素发酵的影响。结果表明,正十二烷作为氧载体的效果较好,能有效提高林肯链霉菌发酵合成林可霉素的能力。在发酵开始的第24 h添加4%的正十二烷,在摇瓶和发酵罐中发酵,可以分别提高林可霉素的效价26.3%和28.8%。     

纳滤膜分离洁霉素生产废水的试验研究

针对洁霉素生产废水,采用国内外多种纳滤膜在不同工况条件下进行了试验研究,筛选和确定了适用纳滤膜的种类和其最佳工作条件,为纳滤膜的进一步应用奠定了基础。