Metabolites of A Novel Antibiotic Bitespiramycin in Rat Urine and Bile

A sensitive analytical method to identify active metabolites of bitespiramycin in rat urine and bile was developed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI-MSn). Bitespiramycin and its major active metabolites in rat urine and bile were isolated and identified as Ml serial (spiramycin Ⅰ, Ⅱ, Ⅲ), M2 serial (platenomycin Al, josamycin and leucomycin Al) and M3 serial (deisovalerylplatenomycin Al, deisovaleryl-josamycin, deisovalerylleucomycin Al).

Improved production of spiramycin by mutant Streptomyces ambofaciens

Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S. ambofaciens XC 2-37 were studied. The potency of S. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.

液相色谱-串联质谱法同时测定鸡肉中的螺旋霉素(Ⅰ型)和新螺旋霉素

目的：建立鸡肉中螺旋霉素（I 型）和新螺旋霉素的液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry, LC-MS/MS）检测方法。方法样品经磷酸盐缓冲溶液（0.1 mol/L, pH=8.0）提取,正己烷脱脂后,经HLB固相萃取柱净化,氮吹浓缩,采用LC-MS/MS,在正离子模式下进行检测。结果该方法在螺旋霉素（I 型）和新螺旋霉素的浓度为0~200μg/kg 范围内有良好的线性关系,相关系数 r〉0.995,定量限均为10μg/kg。螺旋霉素（I 型）和新螺旋霉素在3个不同添加水平下的平均回收率为87.1%~102%,相对标准偏差为3.45%~6.56%。结论该方法简便、快速,准确度和精密度良好,可以满足鸡肉中螺旋霉素（I型）和新螺旋霉素的测定需要。

丙三醇对螺旋霉素Ⅰ发酵的影响及机理分析

以提高螺旋霉素Ⅰ产量及降低杂质D(Spiramycin V)组分质量分数为目标,研究添加丙三醇对螺旋霉素I产生菌生二素链霉菌发酵的影响,并对其影响机理进行分析。摇瓶添加最终体积分数为0.4%的丙三醇使螺旋霉素I效价提高17.12%,杂质D质量分数降低21.39%。15 L发酵罐的放大实验表明,添加最终体积分数为0.4%的丙三醇,螺旋霉素I最终效价达到23314 U/mL,相比对照组(18329 U/mL)提高27.20%,最终杂质D质量分数为8.84%,与对照组(11.99%)相比降低了26.27%。相关基因转录水平研究发现,聚酮合酶基因srm10(内酯环合成相关基因),氨基转移酶基因srm20(福洛氨糖合成相关基因)与甲基转移酶基因srm33(碳霉糖合成相关基因)的转录水平提高。结果表明,在发酵15 h添加最终体积分数为0.4%的丙三醇,能提高内酯环合成相关基因及糖基合成相关基因的转录水平,从而提高螺旋霉素I效价,降低杂质D组分的质量分数。

螺旋霉素对金黄色葡萄球菌耐药突变体的转录组特征分析

螺旋霉素Ⅰ是一类重要的大环内酯类抗生素,但由于耐药菌的产生限制了临床使用。为了在转录水平上全局性的了解细菌耐药前后对抗生素响应上的变化和机制,通过基于RNA-seq方法对螺旋霉素敏感菌株Staphylococcus aureus ATCC29213和其诱导耐药突变菌株S.aureus ATCC29213-R在抗生素压力诱导前后菌体的转录组表达变化进行了分析。研究结果证明了螺旋霉素Ⅰ可诱导S.aureus ATCC29213产生耐药菌株,并通过测序发现该菌的23S rRNA 2089位A→C颠换,该突变位点在S.aureus中是首次报道。此外,还发现螺旋霉素Ⅰ能使S.aureus ATCC29213-R菌株的322个基因上调,82个基因下调,其中涉及精氨酸降解的基因arc A,arc C和arg F表达水平分别上调35,18.05和30.84倍,涉及精氨酸合成的基因arg H和arg G分别下调13.51和21.45倍,其综合作用减少精氨酸的内源性合成;因此,精氨酸代谢途径可能成为治疗23S RNA突变耐药金黄色葡萄球菌感染新的潜在靶点。

Filtration Process of the Spiramycin Fermentation Broth

This paper presents the effects of acidity and additive pretreatment on the filtering rate and Spiramycin (SPM) concentration in the filter liquor of SPM fermentation broth. The experimental results show that the SPM peak value in filter liquor is obtained at pH 5.5 with either 0.1% methanal or 0.1% BAPE. It is also indicated that there exists a dissolution equilibrium of proteins from the experiment results. The soluble proteins are denatured due to the too high/low acidity and then precipitate. Usually, the amount of soluble proteins reaches its lowest level in pH range of 6 0 6 5. The protein precipitation will, together with other suspended solids particles, contribute to the final SPM concentration in the filter liquor. This paper assumes that the contribution is the result of the adsorption equilibrium of SPM on the surfaces of suspended solids. For a satisfactory explanation, the revised Langmuir adsorption theory was employed and a model was developed.

Visible light driven mineralization of spiramycin over photostructured N-doped TiO2 on up conversion phosphors

A novel visible light-active photocatalyst formulation（NdT/OP） was obtained by supporting N-doped TiO2（NdT） particles on up-conversion luminescent organic phosphors（OP）. The photocatalytic activity of such catalysts was evaluated for the mineralization process of spiramycin in aqueous solution. The effect of NdT loading in the range 15–60 wt.% on bulk and surface characteristics of NdT/OP catalysts was investigated by several chemicophysical characterization techniques. The photocatalytic performance of NdT/OP catalysts in the removal of spyramicin from aqueous solution was assessed through photocatalytic tests under visible light irradiation. Total organic carbon（TOC） of aqueous solution,and CO and CO2 gas concentrations evolved during the photodegradation were analyzed. A dramatic enhancement of photocatalytic activity of the photostructured visible active NdT/OP catalysts,compared to NdT catalyst,was observed. Only CO2 was detected in gas-phase during visible light irradiation,proving that the photocatalytic process is effective in the mineralization of spiramycin,reaching very high values of TOC removal. The photocatalyst NdT/OP at 30 wt.% of NdT loading showed the highest photocatalytic activity（58%of TOC removed after 180 min irradiation against only 31% removal after 300 min of irradiation of NdT）. We attribute this enhanced activity to the high effectiveness in the utilization of visible light through improved light harvesting and exploiting. OP particles act as ＂photoactive support＂,able to be excited by the external visible light irradiation,and reissue luminescence of wavelength suitable to promote NdT photomineralization activity.

QuECHERS-HPLC-MS测定人血浆中3种大环内酯类抗菌药物及其代谢物含量

目的建立测定人血浆中3种大环内酯类抗菌药物(红霉素、地红霉素、螺旋霉素Ⅰ)及其代谢物(脱水红霉素、红霉素A烯醇醚、红霉胺、新螺旋霉素Ⅰ)的分析方法。方法用乙腈溶液提取,Qu ECHERS方法净化,采用无水硫酸镁和无水乙酸钠沉淀蛋白和盐析分层,无水硫酸镁和石墨碳烯净化,上清液氮气吹干后甲醇复溶待测,用Eclipse Plus C18色谱柱分离,电喷雾正离子模式,多反应离子监测扫描,内标法定量。结果 3种大环内酯类抗菌药物及其代谢物浓度在4~900 ng·mL^(-1)内的线性关系良好(r>0.999),定量限<10 ng·mL^(-1);在3个添加水平下,3种大环内酯类抗菌药物及其代谢物的提取回收率可达81.45%~96.82%,日内精密度<5.00%,日间精密度<10.00%。结论 Qu ECHERS-液相色谱串联三重四级杆质谱测定血浆中3种大环内酯类抗菌药物及其代谢物的分析方法简单,快速,灵敏,特异性强,适用于血浆中大环内酯类抗菌药物及其代谢物的测定。