Project 5

The diurnal fruit fly Drosophila melanogaster expresses circadian and ultradian rhythms of rest (sleep) and activity with activity peaks at dusk and dawn. In addition to circadian rhythms in feeding, depending on the availability and quality of food the fruit fly will express ultradian bouts of feeding. It is unknown whether/how these circadian and ultradian rhythms interact. Starvation or nutrient restriction resulted in changed rhythms of sleep and activity that are regulated by classical neurotransmitters and neuropeptides as possible coupling factors of multiscale rhythms.

In our project we examine the relevant set of neuropeptides and classical neurotransmitters in the different clock neurons that control sleep wake rhythms or feeding behaviour. We will use qualitative and quantitative single cell MALDI –TOF mass spectrometry in combination with single cell transcriptomics, immunocytochemistry, and behavioural genetics to determine the most precise snapshot of the molecular basis of a temporal unit of behaviour. Under different physiological conditions at different times, we will search for rhythmically released peptidergic or aminergic coupling factors. The second part of the project will focus on the roles of kinase TOR (mechanistic target of rapamycin) a major intracellular sensor that integrates nutrient and energy status. TOR-dependent signalling plays a role in insulin-like peptide secreting neurons that regulate circadian rhythms of hunger and satiety. We will examine whether and how TOR-dependent coupling factors are involved in multiscale rhythm-regulation.

Literature:

[1] Diesner, M., & Neupert, S. (2018). Quantification of Biogenic Amines from Individual GFP-Labeled Drosophila Cells by MALDI-TOF Mass Spectrometry. Analytical Chemistry, 90(13), 8035–8043. https://doi.org/10.1021/acs.analchem.8b00961.

[2] Diesner, M., Predel, R., & Neupert, S. (2018). Neuropeptide Mapping of Dimmed Cells of Adult Drosophila Brain. Journal of the American Society for Mass Spectrometry, 29(5), 890–902. https://doi.org/10.1007/s13361-017-1870-1.