报告题目：The circadian coupling factor PDF keeps two clock circuits in antiphase that control either rest or activity in the cockroach circadian clock

报告人：Monika Stengl, Faculty of Biology, Animal Physiology, University of Kassel, Germany

时间地点：2019年9月5日14:00 9408

报告人简介：Prof. Monika Stengl received the international prize for PhD work in University of Arizona, Tucson in 1990. From 1990 to 1992 she was a postdoctoral fellow at the Univerisity of Konstanz, Germany. From 1992 to 2007 she held assistant professor positions at University of Regensburg and University of Marburg. Since 2007, she has been Professor of Animal physiology, University of Kassel, Germany.

Prof. Stengl is interested in sensory transduction and mechanisms of information processing in brains (on the cellular and molecular level) to understand the basis of behavior, learning, and memory. Her primary research topics are: 1. the neuronal and molecular mechanisms of olfactory transduction. She analyzed how odors are detected by sensory receptor neurons of the hawkmoth. Main techniques used are patch clamp of cultured receptor neurons for the analysis of second messenger-gated ion channels and extracellular recordings of olfactory sensilla in intact moths. 2. Circadian rhythms of insects: analysis of circadian pacemakers on the cellular and molecular level. Her work focus on circadian coupling pathways: the function of neuropeptides in circadian rhythm generation and orchestration, neuropeptides as possible coupling signals between oscillators. She investigated peptide-dependent signaling from the cell membrane to the nucleus. Her group use electrophysiological methods, RT PCR, combined with calcium imaging, neuroanatomical, and behavioral assays.

Prof. Stengl is member of ECRO (European Chemoreception Research Organization), AChemS (American Association for Chemical Senses), Society for Neuroscience, Society for Neuroethology, and Society of Biological Rhythms.

报告摘要：

Pigment-dispersing factor immunoreactive neurons (PDF-ir) innervating the accessory medulla (AME), the circadian clock of the Madeira cockroach, control rest-activity rhythms via unknown mechanisms. Extracellular recordings of the AME in vitro found evidence for circadian, as well as for ultradian rhythms in the clock network. Furthermore, single, isolated clock neurons generated regular action potential rhythms in the gamma frequency range (>30 Hz). Application of PDF to the isolated circadian clock triggered PDF-dependent ensemble formation, with all neurons in the ensemble firing phase-coupled, with the same frequency. Thus, it was suggested that PDF gates clock′s inputs and outputs via PDF-dependent phase-coupling. We challenged our hypothesis that PDF-dependent antagonistic ensemble formation during the day keeps two neuronal circuits out of phase that are either sleep- or activity-promoting. In vitro Ca2+ imaging studies with primary cell cultures of the AME, combined with backfills from the contralateral optic stalk and anti-PDF immunocytochemistry searched for antagonistic PDF-autoreceptors. Furthermore, in long-term loose patch clamp recordings of the AME in vivo we examined daytime-dependent electrical activity changes of the circadian clock indicative of PDF-dependent electrical ensemble formation.