耐磷酸盐土霉素菌株选育和发酵的研究

以土霉素生产菌株138^#为出发菌株，经饥饿培养、5-FU、UV、咖啡因复合诱变处理，再用含高磷酸盐的培养基定向筛选，得到高产突变菌株100^#。该突变株遗传特性稳定，代谢特性优于出发菌株，经57m^3发酵罐生产验证，生产稳定，低效价罐批减少59．5％，在磷酸盐浓度提高到0.04％～0.05％时，统计一年的正常罐批平均发酵效价比对照菌株提高5．76％。     

透明颤菌血红蛋白基因在龟裂链霉菌中的表达及其对土霉素合成的影响

目的 考察透明颤菌血红蛋白基因(vgb)在大肠埃希菌(E. coli)和龟裂链霉菌(S. rimosus)中的表达，研究在不同溶氧条件下表达的透明颤菌血红蛋白(VHb)对龟裂链霉菌生长和土霉素合成的影响。方法 将vgb插入表达型质粒pET-28a中，导入E. coli BL21(DE3)用以表达VHb并测定其活性。以整合型质粒pSET152为载体，利用ermE*启动子组成型表达vgb基因，将构建的质粒通过接合转移整合到S. rimosus M4018基因组上，利用CO差示光谱法和SDS-PAGE鉴定两个重组菌中的血红蛋白。在5L罐上考察不同溶氧条件下VHb的表达对重组龟裂链霉菌生长和土霉素合成的影响。结果 重组大肠埃希菌和重组龟裂链霉菌都能够表达具有生物活性的VHb，发酵结果表明，在117h时与对照菌相比，重组龟裂链霉菌在高氧和低氧条件下的干重分别提高了6%和32%，同时单位干重土霉素的产量分别提高了41%和93%。结论 VHb在重组龟裂链霉菌中成功表达，改善了菌体的生长和土霉素的合成，为解决工业发酵过程中氧限制问题提供了策略。     

Combined effects of oxytetracycline and Pb on earthworm Eisenia fetida

Combined effects of oxytetracycline (OTC) and Pb on lysosomal membrane stability and coelomocyte apoptosis of earthworm were studied in the paper. Compared with control, the lysosomal membrane stability decreased and coelomocyte apoptosis increased in the treatments of single OTC and Pb contamination. As for compound pollution, combined effect of (5 mg/kg OTC + 50 mg/kg Pb) treatment on earthworm lysosomal was synergistic (except 28 d). However, it was antagonistic at higher concentration of (10 mg/kg OTC + 50 mg/kg Pb) and (20 mg/kg OTC + 50 mg/kg Pb) treatment. In addition, coelomocyte apoptosis of earthworm decreased significantly compared with single OTC, indicating an antagonistic reaction. And joint toxicity of OTC and Pb decreased significantly with the increasing OTC concentration.     

UPLC-ESI-MS/MS检测畜、禽肉中土霉素、四环素、金霉素残留量

目的：建立超高效液相色谱-电喷雾串联四极杆质谱快速测定畜、禽肉中土霉素、四环素、金霉素的方法。方法：采用超高效液相色谱-电喷雾串联四极杆质谱仪,多离子反应监测（MRM）定量法,通过对试样净化预处理、色谱条件、质谱参数等的优化选择和方法回收率、精密度等的验证,建立了同步准确定量测定肉类食品中土霉素、四环素、金霉素的理想方法。结果：土霉素、四环素、金霉素的最低检出限（LOD）分别为0.1、0.1、0.5μg/kg,在5.0-80.0 ng/ml的线性范围内,相关系数r均大于0.99,回收率在82.6%-111%。结论：采用液相色谱-电喷雾串联四极杆质谱仪,可快速测定畜、禽肉样品中土霉素、四环素、金霉素含量,结果准确可靠,重复性好,灵敏度高。     

SPE-HPLC法同时测定水产品中四种抗生素残留的研究

目的 :为快速、简便、灵敏的检测水产品中土霉素、四环素、金霉素、氯霉素残留 ,建立了固相萃取(SPE) -高效液相色谱 (HPLC)分析法。方法 :样品高氯酸沉淀蛋白质 ,超声波提取 ,固相萃取 ,高效液相色谱法同时测定 4种抗生素。固相萃取小柱为ZORBAXSPEC18Cart,洗脱液为 5 0 %甲醇水 ;色谱柱为SUPELCODiscoveryC185 μm 2 5 0× 4 . 6mm ,流动相为 0 . 0 1mol/L　磷酸二氢钠 +0 . 0 0 1mol/L　EDTA :甲醇 =6 0∶4 0 (V/V ,pH =2. 0 ) ,流速为 0 .8ml/min ,检测波长为 2 6 8nm。结果 :本方法的最低检出浓度分别为 :土霉素 (0. 0 18mg/kg)、四环素 (0 . 0 2 5mg/kg)、金霉素(0 .0 4 3mg/kg)、氯霉素 (0 . 0 10mg/kg)、标准曲线线性良好 ,其回归方程及相关系数r分别为土霉素 :y =5 6 . 32 15x -0 . 90 0 4 ,r=0 .9999;四环素 :y =4 2 .8345x - 1 .14 84 ,r=0 .9999;金霉素 :y =2 3 0 0 97x - 0 . 96 30 ,r =0 . 9999;氯霉素 :y=38 .8332x+0 . 16 5 5 ,r=0 . 9999,回收率在 93%～ 10 1%之间 ,相对标准偏差小于 1 .9%。结论 :以超声波萃取 ,经固相柱净化、用二极管阵列检测器是一种快速、灵敏、简便的测定水产品中抗生素残留的高效液相色谱方法。     

偏最小二乘紫外分光光度法测定土霉素生物效价

土霉素的含量测定,各国标准仍主要采用微生物检定法。该法虽然能反映其生物效价,但准确度不高,费时。长期以来人们试图寻求理化方法来取代微生物法。紫外分光光度法简便、快速,广泛地运用于药物分析     

高效液相色谱法测定水产品中土霉素、四环素、金霉素

目的：建立高效液相色谱法测定水产品中土霉素、四环素、金霉素.方法：选择乙腈-0.01 mol/L柠檬酸溶液为流动相体系,采用梯度洗脱,流速0～6 min为0.4 ml/min;6～7 min为0.4～0.8 ml/min;7～12 min为0.8 ml/min.结果：当检测波长为355 nm时,土霉素检出限为0.010 mg/kg,四环素为0.008 mg/kg,金霉素为0.035 mg/kg,线性范围为0.04～1.0 mg/kg,相关系数为0.999,相对标准偏差为1.35%,加标回收率为85%～120%.结论：此测定方法简便,结果可靠,灵敏度高.     

Normal bone particles are preferentially resorbed in the presence of osteocalcin-deficient bone particlesIn vivo

Summary In anin vivo model of osteoclastic bone resorption, we previously showed that osteocalcin-deficient bone particles (BPs), derived from warfarin-treated rats, were resorbed 50% as well as normal BPs and that they recruited fewer osteoclastic cells with decreased tartrate-resistant acid phosphatase (TRAP) activity. In order to determine the specificity of the resorption response, we evaluated the fate of implanted mixtures of normal and osteocalcin-deficient BPs. Normal and warfarin-treated donor rats were prelabeledin vivo with oxytetracycline to permit identification of BPs from either source. Normal, osteocalcin-deficient, and 50∶50 mixtures of BPs (either labeled or unlabeled) were implanted into normal rats and recovered 12 days later for enzymatic (TRAP) and nondecalcified histomorphometric analyses. The incorporated oxytetracycline had no signficant effect on resorption of bone particles. The recovered osteocalcin-deficient BPs were surrounded by fewer osteoclastic cells, were resorbed less, and contained less extractable TRAP activity than normal BPs. In mixed BP implants with normal and osteocalcin-deficient BPs, each type of bone particle elicited the same tissue response as when implanted separately. Remarkably, the different particles evoked dissimilar osteoclastic responses and were resorbed to different extents, even when adjacent within the same implant. These data suggest that osteocalcin may act as a substrate signal for resorption and that osteocalcin in the normal BPs does not influence the cellular response to adjacent osteocalcin-deficient BPs.     

HPLC法测定滴强灵胶囊中3组分的含量

目的:建立滴强灵胶囊中3组分的HPLC测定方法。方法:以COSMOSIL C₁₈（250 mm×4.6 mm,5μm）为色谱柱,以醋酸铵溶液[0.25 mol·L^-1醋酸铵溶液-0.05 mol·L^-1EDTA-2Na溶液-三乙胺（100:10:1）,用醋酸调pH至7.5]-乙腈（88:12）为流动相测定甲硝唑和土霉素的含量,流速1 ml·min^-1,检测波长280 nn,柱温30℃;以甲醇-水（60:40）为流动相测定醋酸泼尼松的含量,流速1 ml·min^-1,检测波长240 nm,柱温30℃。结果:建立的HPLC法能排除辅料对主药中3组分的干扰,甲硝唑、土霉素、醋酸泼尼松的含量测定的线性范围分别为0.04～0.80 mg·ml^-1（r=0.999 9）,0.02～0.40 mg·ml^-1（r=0.999 9）和0.02～0.40 mg·ml^-1（r=0.999 9）;平均回收率分别为99.94%（RSD=0.07%）、99.85%（RSD=0.09%）、98.16（RSD=1.58%）（n=6）。结论:本法操作简便可靠,可用于滴强灵胶囊的质量控制。     

Simultaneous determination of streptomycin and oxytetracycline in agricultural antimicrobials by CZE after an experimental design

A capillary zone electrophoresis (CZE) method was developed and validated for the simultaneous determination of both streptomycin (STP) and oxytetracycline (OTC) in bactericidal products to be used in agriculture. Using fused-silica capillaries, the influence of the electrolyte composition, pH and concentration, as well as temperature and applied voltage were investigated using a central composite design to optimize the method. The optimized electrophoretic conditions were as follows: 0.10 M sodium phosphate, pH 2.5, 7.0 kV and 20.0 degrees C. The method was validated for STP and OTC determination in agricultural formulations through the following performance criteria: linearity and linear range, sensitivity, selectivity, intra-day and inter-day precision, detectability, accuracy and ruggedness. This optimized CZE-method for the identification and quantification of STP and OTC is a potential alternative method to the HPLC methods described by the US Pharmacopeia, with the advantage that the same method could be used for the simultaneous determination of these different antibiotics.