Leucomycin A13

Aim:To identify the components of acetylleucomycin and its hydrolytic products by LC-MS.Methods:Acetylleucomycin was separated on a Diamonsil C18 column with 0.1 mol x L(-1) ammonium acetate-acetontrile (35 : 65) as mobile phase. The LC-MS was equipped with an electorspray ion source (ESI), which was set at the positive ion mode, and the mass spectra of each component in chromatogram were obtained with difference cone voltage.Results:The components of acetylleucomycin and its hydrolytic products can be separated by HPLC. The components were identified according to the molecular weight and its major mass fragment ions. The major components identified in domastic acetylleucomycin were acetylleucomycin A4, A5; acetylleucomycin A1, A3; acetylleucomycin A6, A7, and acetylleucomycin A13. The hydrolytic products of acetylleucomycin were not kitasamycin, but some non-complete hydrolytic product.Conclusion:The method is rapid, sensitive and specific. It' s suitable to application in the fields of multi-components antibiotics analysis.

A rapid, simple, highly efficiency analytical method for detecting kitasamycin A1, A4, A5, and A13 in different feedstuffs was successfully developed by combining enhanced matrix removal (EMR) lipid cartridge and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). After extraction with acetonitrile, the sample supernatants were directly passed through the EMR lipid cartridge. Then, the cartridge was rinsed and eluted with acetonitrile and methanol, respectively, followed by UHPLC-MS/MS analysis with positive mode using multiple reaction monitoring. Optimized pretreatment procedure without solvent conversion, multiple nitrogen drying steps and activated cartridge before loading, and no significant interference were found during the analysis of different types of animal feedstuffs. Excellent sensitivity (Limit of quantification, LOQ) of kitasamycin A1, A4, A5, and A13 was 1.1-2.0 µg/kg. Satisfactory recoveries of kitasamycin A1, A4, A5, and A13 in different feedstuffs were from 74.0% to 98.8%, with the relative standard deviations (RSDs) below 10.4%, and good linear correlation coefficient (r)>0.9990 in the matrix matched standard curve range of 0.02-50.0 µg/L. Results demonstrated that the developed method exhibited excellent linearity, accuracy, precision, sensitivity, and the feasibility of using this method in kitasamycin determination of animal feedstuffs. The method was evaluated using the greenness analysis method through Eco-Scale assessment tool.

The behaviors of the Macrolide-Lincosamide-Streptogramin (MLS) resistance genes were investigated in an anaerobic-aerobic pilot-scale system treating spiramycin (SPM) production wastewater. After screening fifteen typical MLS resistance genes with different mechanisms using conventional PCR, eight detected genes were determined by quantitative PCR, together with three mobile elements. Aerobic sludge in the pilot system exhibited a total relative abundance of MLS resistance genes (per 16S rRNA gene) 2.5 logs higher than those in control samples collected from sewage and inosine wastewater treatment systems (P < 0.05), implying the presence of SPM could induce the production of MLS resistance genes. However, the total relative gene abundance in anaerobic sludge (4.3 × 10(-1)) was lower than that in aerobic sludge (3.7 × 10(0)) despite of the higher SPM level in anaerobic reactor, showing the advantage of anaerobic treatment in reducing the production of MLS resistance genes. The rRNA methylase genes (erm(B), erm(F), erm(X)) were the most abundant in the aerobic sludge (5.3 × 10(-1)-1.7 × 10(0)), followed by esterase gene ere(A) (1.3 × 10(-1)) and phosphorylase gene mph(B) (5.7 × 10(-2)). In anaerobic sludge, erm(B), erm(F), ere(A), and msr(D) were the major ones (1.2 × 10(-2)-3.2 × 10(-1)). These MLS resistance genes (except for msr(D)) were positively correlated with Class 1 integron (r(2) = 0.74-0.93, P < 0.05), implying the significance of horizontal transfer in their proliferation.