Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonin...Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonine, to the Streptomyces tenebrabrius UD2 fermentation medium substantially increases the production of apramycin with little effect on the growth of mycelia, indicating that glycine and/or serine might be involved in the biosynthesis of apramycin. The 13C-NMR analysis of [2-13C] glycine-fed (25% enrichment) apramycin showed that glycine specifically and efficiently incorporated into the only N-CH3 substituent of apramycin on the C7′ of the octodiose moiety. We noticed that the in vivo concentration of S-adenosyl methionine increased in parallel with the addition of glycine, while the addition of methione in the fermentation medium significantly decreased the productivity of apra-mycin. Therefore, the methyl donor function of glycine is proposed to be involved in the methionine cycle but methionine itself was proposed to inhibit the methylation and methyl transfer processes as previously reported for the case of rapamycin. The 15N NMR spectra of [2-13C,15N]serine labeled apramycin indicated that serine may also act as a limiting precursor contributing to the ―NH2 substituents of apramycin.展开更多
The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD...The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50 2% and 55 0%, COD removals were 40 0% and 46 0%, and the ratio of BOD_5/COD was increased to 0 49 and 0 54 with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5/COD was increased to 0 45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO. HO_2· may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2/Al_2O_3 in WAO of apramycin wastewater.展开更多
建立了猪肾中安普霉素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。猪肾样品以磷酸二氢钾溶液提取,经HLB固相萃取柱净化后,采用CAPCELL PAK MGⅡC_(18)(2.0 mm×150 mm,5μm)色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相...建立了猪肾中安普霉素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。猪肾样品以磷酸二氢钾溶液提取,经HLB固相萃取柱净化后,采用CAPCELL PAK MGⅡC_(18)(2.0 mm×150 mm,5μm)色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相进行梯度洗脱。采用电喷雾离子源正离子模式扫描,多反应监测(MRM)模式进行检测,基质匹配同位素内标法定量。安普霉素在20~200μg/L质量浓度范围内线性良好,相关系数(r^(2))为0.9993,方法定量下限为10.0μg/kg。在10、20、100μg/kg加标水平下的平均回收率为85.5%~94.6%,相对标准偏差(RSD)不大于5.9%。该方法基于HLB固相萃取柱净化,基质匹配同位素内标法定量,具有操作简单、定性准确、灵敏度高的特点,适用于猪肾中安普霉素残留量的测定。展开更多
文摘Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonine, to the Streptomyces tenebrabrius UD2 fermentation medium substantially increases the production of apramycin with little effect on the growth of mycelia, indicating that glycine and/or serine might be involved in the biosynthesis of apramycin. The 13C-NMR analysis of [2-13C] glycine-fed (25% enrichment) apramycin showed that glycine specifically and efficiently incorporated into the only N-CH3 substituent of apramycin on the C7′ of the octodiose moiety. We noticed that the in vivo concentration of S-adenosyl methionine increased in parallel with the addition of glycine, while the addition of methione in the fermentation medium significantly decreased the productivity of apra-mycin. Therefore, the methyl donor function of glycine is proposed to be involved in the methionine cycle but methionine itself was proposed to inhibit the methylation and methyl transfer processes as previously reported for the case of rapamycin. The 15N NMR spectra of [2-13C,15N]serine labeled apramycin indicated that serine may also act as a limiting precursor contributing to the ―NH2 substituents of apramycin.
文摘The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50 2% and 55 0%, COD removals were 40 0% and 46 0%, and the ratio of BOD_5/COD was increased to 0 49 and 0 54 with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5/COD was increased to 0 45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO. HO_2· may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2/Al_2O_3 in WAO of apramycin wastewater.
文摘建立了猪肾中安普霉素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。猪肾样品以磷酸二氢钾溶液提取,经HLB固相萃取柱净化后,采用CAPCELL PAK MGⅡC_(18)(2.0 mm×150 mm,5μm)色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相进行梯度洗脱。采用电喷雾离子源正离子模式扫描,多反应监测(MRM)模式进行检测,基质匹配同位素内标法定量。安普霉素在20~200μg/L质量浓度范围内线性良好,相关系数(r^(2))为0.9993,方法定量下限为10.0μg/kg。在10、20、100μg/kg加标水平下的平均回收率为85.5%~94.6%,相对标准偏差(RSD)不大于5.9%。该方法基于HLB固相萃取柱净化,基质匹配同位素内标法定量,具有操作简单、定性准确、灵敏度高的特点,适用于猪肾中安普霉素残留量的测定。
