Localization and interaction of PDF neuropeptides in Onychophora and Tardigrada

FG Zoologie

PDF-like immunoreactivity in the brain of the onychophoran Euperipatoides rowelli. Vibratome cross-section of the head triple-labeled with acetylated α-tubulin (light-blue) and β-PDH antisera (glow mode), and phalloidin-rhodamine as f-actin counterstaining (dark blue). Arrowheads point to the large PDF-ir somata of the dorsal cluster. Asterisks indicate the position of the smaller PDF-ir somata of the ventral cluster. Abbreviations: at, antennal tract; bw, body wall musculature; cb, central body; cn, central brain neuropil; la, lateral brain neuropil; mb, mushroom body; pe, perikaryal layer. Scale bar = 150 µm. Modified from Mayer et al. 2015, J. Comp. Neurol. 523: 1865–1885.

Project members: Lars Hering, Prof. Georg Mayer

Although numerous studies have been performed on pigment-dispersing factor neuropeptides (PDFs) in arthropods – a neuropeptide, which acts as a circadian neuromodulator – only little is known about the expression and interaction of PDFs with their receptors in the closest relatives of arthropods, the onychophorans (velvet worms) and tardigrades (water bears). The aim of our project is therefore to localize the two identified PDF neuropeptides in onychophorans and the three PDFs in tardigrades together with their respective receptors using immunolabelling with specific antibodies. We will further analyze their ligand-receptor interactions as well as their influence on the daylight-dependent activities of the animals studied. These results will provide insights into the regulation mechanisms and the evolution of the circadian system in Panarthropoda (Onychophora, Tardigrada and Arthropoda).