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Project E4 - High-resolution and imaging mass spectrometry

Project description

Background: Within the last decade, high-resolution mass spectrometry has gained importance in the field of biological and medical research through the development of modern ionization processes and further progress in instrumentation. Thanks to the high mass resolution of current instruments, thousands of different mass signals can be simultaneously detected in complex biological samples and identified via highly precise mass determination1. Further development of some ionization methods for imaging mass spectrometry allows the generation of chemical distribution images of the contents.2 A typical high resolution of about 10 µm allows the visualization of tissue structures even in small organisms such as insects and worm parasites that have a total size of < 500 µm. Different methods have already been developed in order to prepare such fragile samples for measurement, which also includes the production of thin slices of tissue.

The anatomical characteristics of the Anopheles mosquito could be made chemically visible with distribution images of phospholipids through imaging mass spectrometry investigations.3

The protocols and techniques developed can be transferred to target organisms of the LOEWE Center DRUID and further optimized. Schistosomes (Schistosoma mansoni) have already been examined in experiments as reference organisms for worm-like parasites. These experiments successfully demonstrated the distribution of various status and gender-specific phospholipids (Fig. E4). The distribution and enrichment of imatinib, one of the potential drugs against schistosomes, could be displayed in the outer medulla of a rat kidney with a spatial resolution of 10 µm.4

Fig. E4a. Optical image of a cross section of paired S. Mansoni b. Mass spectrometric distribution image of various chemical compounds. The red-colored molecule is characteristic of the female animal.

Scientific goals: The aim is to adapt, expand, and use imaging mass spectrometry examination methods to answer questions arising in the LOEWE Center. In particular, increasing spatial resolution to 1 µm for the investigation of the parasites and the infected host cells is of importance.5 Moreover, the examination of non-planar, intact objects (worm parasites, insects) by means of 3D surface examination is to be developed. This completely new method will be usable in many ways in the center, especially for examining the (bio-) chemical surfaces of pathogenic host interactions. Within the DRUID Center, metabolomic, lipidomic, and proteomic characterizations of parasites and pathogens are to be examined at different stages of development.

 


References E4: 1. Hu et al. (2005) J Mass Spectrom 40:430-43 2. Spengler (2015) Anal Chem 87:64 3. Khalil et al. (2015) Anal Chem 87:11309 4. Rompp et al. (2011) Anal Bioanal Chem 401:65 5. Kompauer et al. (2016) Nat Methods doi:10.1038/nmeth.4071.