Magnetic Resonance Spectroscopy of live Drosophila melanogaster using Magic Angle Spinning

Summary

This technique enables the use of high-resolution magic angle spinning proton MR spectroscopy (HRMAS 1H-MRS) for molecular characterization of live Drosophila melanogaster with a conventional 14.1 tesla spectrometer equipped with an HRMAS probe.

Abstract

High-Resolution Magic Angle Spinning (HRMAS) proton magnetic resonance spectroscopy (¹H-MRS) is a novel non-destructive technique that improves spectral line-widths and allows high-resolution spectra to be obtained from extracts, intact cells, cell cultures, and more importantly intact tissue to investigate relationships between metabolites and cellular processes. In vivo HRMAS ¹H-MRS studies have yet to be reported in the live fruit fly Drosophila melanogaster. Drosophila, as a simpler genetic organism, allows the multiple biological functions and various evolutionarily conserved signaling pathways to be examined at the whole organism level and it is a useful model for investigating genetics and physiology. To this end, we developed and implemented an in vivo HRMAS ¹H-MRS method to investigate live Drosophila at 14.1 T. Here, we outline an HRMAS ¹H-MRS protocol for the molecular characterization of Drosophila with a conventional MR spectrometer equipped with an HRMAS probe. This technique is a novel, in vivo, non-destructive Drosophila metabolite measurement approach, which enables the identification of disease biomarkers and thus may contribute to novel therapeutic development.

Protocol

Part 1: Preparing Drosophila for HRMAS Measurements

1. Using standard flylab procedures ¹, collect newly eclosing flies for 3 days and transfer them to fly vials containing fresh fly food. Incubate the collected flies for 5 days so that the flies will become 5-8 days old just prior to the experiment. Only one sex (usually males) is used for experiments.
2. Use healthy, intact wild type flies to compare with treated e.g. traumatized or genetically altered flies ¹.
3. Place single flies into 2ml tubes containing a piece (~0.2ml) of fly food 24 hours prior to the experiment. These tubes bear a hole in the tube cup ma....

Discussion

With the exception of the recent report of the feasibility of in vivo MRI in fruit flies ⁶, in vivo MRS studies in Drosophila have not yet been reported. In the present protocol, we describe the implementation of a novel in vivo HRMAS ¹H-MRS approach for detecting biologically important molecules. Specifically, we detected lipids and small metabolites in live Drosophila flies at 14.1 T in approximately 45 min, which allows adequate acquisition time, while.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Deuterium oxide	Reagent	Sigma-Aldrich	7789-20-0
3-(trimethylsilyl)propionic-2,2,3,3-d4 acid	Reagent	Sigma-Aldrich	24493-21-8
agar, sucrose, yeast, cornmeal	Food	Genesee Scientific		http://www.flystuff.com/
Oregon RS or Canton-S flies	Adult fly lines	Bloomington Stock center		http://flystocks.bio.indiana.edu/
Paintbrush	Equipment			(size 0)
2ml tubes	Equipment	Fisher Scientific	K749521-1590
Fly incubators	Equipment			high humidity capacity (60-75%), adjustable temperature, and a 12 h:12 h light: dark cycle.
Bruker Bio-Spin Avance NMR spectrometer (600.13 MHz) 4mm triple resonance (1H, 13C, 2H) HRMAS probe	Equipment	Bruker Corporation
BTO-2000 unit in combination with a MAS pneumatic unit	Equipment	Bruker Corporation
4mm zirconium oxide rotor (capacity 50 ul)	Equipment	Bruker Corporation	B3829 (Bruker store)
MestReC (Mestrelab Research)	Software			1D NMR spectra analysis http://mestrelab.com/
SPARKY 3, USCF	Software			2D NMR spectraanalysis http://www.cgl.ucsf.edu/home/sparky/