Favaro Gabriella, Bogialli Sara, Di Gangi Iole Maria, Nigris Sebastiano, Baldan Enrico, Squartini Andrea, Pastore Paolo, Baldan Barbara
Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
Department of Biology, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy.
Rapid Commun Mass Spectrom. 2016 Oct 30;30(20):2237-52. doi: 10.1002/rcm.7705.
The plant endophyte Bacillus licheniformis, isolated from leaves of Vitis vinifera, was studied to individuate and characterize the presence of bioactive lipopeptides having amino acidic structures.
Crude extracts of liquid cultures were analyzed by ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole time-of-flight (QTOF) mass analyzer. Chromatographic conditions were optimized in order to obtain an efficient separation of the different isobaric lipopeptides, avoiding merged fragmentations of co-eluted isomeric compounds and reducing possible cross-talk phenomena. Composition of the amino acids was outlined through the interpretation of the fragmentation behavior in tandem high-resolution mass spectrometry (HRMS/MS) mode, which showed both common-class and peculiar fragment ions. Both M + H and M + Na precursor ions were fragmented in order to differentiate some isobaric amino acids, i.e. Leu/Ile. Neutral losses characteristic of the iso acyl chain were also evidenced.
More than 90 compounds belonging to the classes of surfactins and lichenysins, known as biosurfactant molecules, were detected. Sequential LC/HRMS/MS analysis was used to identify linear and cyclic lipopeptides, and to single out the presence of a large number of isomers not previously reported. Some critical issues related to the simultaneous selection of different compounds by the quadrupole filter were highlighted and partially solved, leading to tentative assignments of several structures. Linear lichenysins are described here for the first time.
The approach was proved to be useful for the characterization of non-target lipopeptides, and proposes a rationale MS experimental scheme aimed to investigate the difference in amino acid sequence and/or in the acyl chain of the various congeners, when standards are not available. Results expanded the knowledge about production of linear and cyclic bioactive compounds from Bacillus licheniformis, clarifying the structures of isomeric forms, and enabling the use of selected endophytes to produce fungicides for eco-friendly biocontrol. Copyright © 2016 John Wiley & Sons, Ltd.
对从葡萄叶中分离出的植物内生菌地衣芽孢杆菌进行研究，以确定并表征具有氨基酸结构的生物活性脂肽的存在情况。
通过超高效液相色谱（UHPLC）与四极杆飞行时间（QTOF）质谱仪联用，对液体培养物的粗提物进行分析。优化色谱条件，以实现不同等压脂肽的有效分离，避免共洗脱异构体化合物的合并碎裂，并减少可能的串扰现象。通过串联高分辨率质谱（HRMS/MS）模式下碎裂行为的解析，勾勒出氨基酸组成，该模式显示了常见类型和特殊的碎片离子。对M + H和M + Na前体离子均进行碎裂，以区分一些等压氨基酸，即亮氨酸/异亮氨酸。还证实了异酰基链的中性损失特征。
检测到90多种属于表面活性素和地衣素类别的化合物，这些化合物被称为生物表面活性剂分子。采用连续LC/HRMS/MS分析来鉴定线性和环状脂肽，并筛选出大量先前未报道的异构体的存在。突出并部分解决了与四极杆过滤器同时选择不同化合物相关的一些关键问题，从而对几种结构进行了初步归属。本文首次描述了线性地衣素。
该方法被证明可用于非目标脂肽的表征，并提出了一种合理的质谱实验方案，旨在在没有标准品的情况下研究各种同系物氨基酸序列和/或酰基链的差异。结果扩展了对地衣芽孢杆菌产生线性和环状生物活性化合物的认识，阐明了异构体形式的结构，并使得能够利用选定的内生菌生产用于生态友好型生物防治的杀菌剂。版权所有© 2016约翰威立父子有限公司。
