AVS 64th International Symposium & Exhibition
    Biomaterial Interfaces Division Thursday Sessions
       Session BI+AS+SA-ThM

Paper BI+AS+SA-ThM1
Lipid Involvement in the Regenerative Processes of Dugesia dorotocephala - A GCIB ToF-SIMS Imaging Study

Thursday, November 2, 2017, 8:00 am, Room 12

Session: Characterisation of Biological and Biomaterial Surfaces
Presenter: Tina Angerrer, University of Washington
Authors: T.B. Angerrer, University of Washington
M.J. Taylor, University of Washington
D.J. Graham, University of Washington
L.J. Gamble, University of Washington
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Dugesia dorotocephala are planaria belonging to the class of Turbellaria, or non-parasitic flat worms. They are best known for their fascinating regenerative abilities, which allow them to be cut into more than 200 pieces, each piece missing essential parts necessary for the worms’ survival and each re-growing a new flatworm. This level of reorganization involves a complex interplay of a wide range of molecules that varies spatially and temporally but is still poorly understood.

Recently the involvement of peptides and proteins in the process of regrowing the head and developing a new central nervous system has been studied by Sweedler et al.[1] using MALDI imaging. MALDI, in contrast to TOF-SIMS imaging, is capable of studying the distributions of peptides in tissue but spatial resolution is limited and molecules of interest have to be partially predetermined by the choice of matrix.

Using the J105-3D Chemical Imager, (Ionoptika Ltd) equipped with a 40 keV gas cluster ion beam (GCIB), molecules with sizes up to 2000 Da can be localized at a cellular scale, with spatial resolutions better than 3 µm.[2] Since ToF-SIMS is a label free technique, it can be used in an untargeted discovery approach which, in biological samples, is mainly used to study lipid distributions.

Lipids are a diverse group of molecules fulfilling numerous functions such as energy storage and cell signaling, however lipid and fatty acid data for Dugesia in general is very limited and their localizations completely unknown.[3] Our studies were targeted at establishing a full body lipid profile for the different organ systems present in Dugesia as well as monitoring their changes due to stem cell migration during head regrowth and eye/CNS regeneration.

Dugesia flatworms were sectioned on a cryomicrotome at -20 °C and slices were placed on ITO coated glass. After preparation samples were immediately taken to the lab for analysis. Sample preparation and transport time was kept to less than 2 hours to minimize lipid degradation. After SIMS analysis, optical images were acquired in order to facilitate identification of structures seen within the worms. To deal with the increased spectral and spatial complexity provided by our improved instrumental capabilities, imaging PCA was used to “untangle” the data. In this presentation we will present the results of our studies showing the unique lipid distributions throughout Dugesia cross sections and discuss their relevance.

[1] T. H. Ong, et al., J Biol Chem 2016, 291, 8109-8120.

[2] T. B. Angerer, et al., Int J Mass Spectrom 2015, 377, 591-598.

[3] F. Meyer, et al., Biochim Biophys Acta 1970, 210, 257-&.