Microscale MALDI Imaging of Outer-Layer Lipids in Intact Egg Chambers from Drosophila melanogaster

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• 作者：Pawel L. Urban ; Chia-Hsien Chang ; June-Tai Wu ; Yu-Chie Chen
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：May 15, 2011
• 年：2011
• 卷：83
• 期：10
• 页码：3918-3925
• 全文大小：945K
• 年卷期：v.83,no.10(May 15, 2011)
• ISSN：1520-6882

文摘

Fruit fly (Drosophila melanogaster) is a standard model organism used in genetics and molecular biology. Phospholipids are building blocks of cellular membranes, and components of a complex signaling network. Here, we present a facile method, based on matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), for molecular imaging of phospholipid distributions in submillimeter-sized components of the fruit fly reproductive system. Individual egg chambers were deposited on a specially prepared MALDI target comprising an aluminum slide with a rough surface created by ablation with a microsecond-laser: this helped to immobilize biological specimens, remove excess of saline solution by adhesive forces, carry out microscopic observations, and facilitated distribution of the MALDI matrix. A continuous-flow ultrasound-assisted spray was used for the deposition of MALDI matrix (9-aminoacridine) onto the sample. The upper surface of the specimen was then scanned with a 355-nm solid-state laser with a preset beam focus of 10 渭m to obtain negative-ion mode MALDI-MS images. Overall, this provided sufficient spatial resolution to reveal micrometer-scale gradient-like patterns of phospholipids along the anterior/posterior axis of egg chambers. Several phosphatidylinositols are seen to be segregated according to the number of unsaturated bonds, with an elevated abundance of polyunsaturated phosphatidylinositols within the oocyte compartment.