Gemperline Erin, Horn Heidi A, DeLaney Kellen, Currie Cameron R, Li Lingjun
Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
Department of Bacteriology, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
ACS Chem Biol. 2017 Aug 18;12(8):1980-1985. doi: 10.1021/acschembio.7b00038. Epub 2017 Jun 27.
Mass spectrometry imaging is a powerful analytical technique for detecting and determining spatial distributions of molecules within a sample. Typically, mass spectrometry imaging is limited to the analysis of thin tissue sections taken from the middle of a sample. In this work, we present a mass spectrometry imaging method for the detection of compounds produced by bacteria on the outside surface of ant exoskeletons in response to pathogen exposure. Fungus-growing ants have a specialized mutualism with Pseudonocardia, a bacterium that lives on the ants' exoskeletons and helps protect their fungal garden food source from harmful pathogens. The developed method allows for visualization of bacterial-derived compounds on the ant exoskeleton. This method demonstrates the capability to detect compounds that are specifically localized to the bacterial patch on ant exoskeletons, shows good reproducibility across individual ants, and achieves accurate mass measurements within 5 ppm error when using a high-resolution, accurate-mass mass spectrometer.
质谱成像技术是一种强大的分析技术，用于检测和确定样品中分子的空间分布。通常，质谱成像技术仅限于分析从样品中部获取的薄组织切片。在这项工作中，我们提出了一种质谱成像方法，用于检测蚂蚁外骨骼外表面上细菌在接触病原体后产生的化合物。切叶蚁与假诺卡氏菌存在特殊的共生关系，这种细菌生活在蚂蚁的外骨骼上，有助于保护它们的真菌园食物源免受有害病原体的侵害。所开发的方法能够对外骨骼上细菌衍生的化合物进行可视化。该方法证明了能够检测到特异性定位于蚂蚁外骨骼上细菌斑块的化合物，在个体蚂蚁之间具有良好的重现性，并且在使用高分辨率、高精度质谱仪时，能够在误差5 ppm范围内实现准确的质量测量。
