Abstract
Optogenetics controls neural activity and behavior in living organisms through genetically targetable actuators and light. This method has revolutionized biology and medicine as it allows controlling cells with high temporal and spatial precision. Optogenetics is typically applied only at short time scales, for instance to study specific behaviors. Optogenetically manipulating behavior also gives insights into physiology, as behavior controls systemic physiological processes. For example, arousal and sleep affect aging and health span. To study how behavior controls key physiological processes, behavioral manipulations need to occur at extended time scales. However, methods for long-term optogenetics are scarce and typically require expensive compound microscope setups. Optogenetic experiments can be conducted in many species. Small model animals such as the nematode C. elegans, have been instrumental in solving the mechanistic basis of medically important biological processes. We developed OptoGenBox, an affordable stand-alone and simple-to-use device for long-term optogenetic manipulation of C. elegans. OptoGenBox provides a controlled environment and is programmable to allow the execution of complex optogenetic manipulations over long experimental times of many days to weeks. To test our device, we investigated how optogenetically increased arousal and optogenetic sleep deprivation affect survival of arrested first larval stage C. elegans. We optogenetically activated the nociceptive ASH sensory neurons using ReaChR, thus triggering an escape response and increase in arousal. In addition, we optogenetically inhibited the sleep neuron RIS using ArchT, a condition known to impair sleep. Both optogenetic manipulations reduced survival. Thus, OptoGenBox presents an affordable system to study the long-term consequences of optogenetic manipulations of key biological processes in C. elegans and perhaps other small animals.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Inka Busack is currently a PhD student of Systems Neuroscience at the University of Göttingen, Germany. She works in the group of Prof. Bringmann with a focus on sleep in C. elegans. She received a Bachelor degree in physics from Princeton University, USA, in 2016. After that she started her PhD work in Prof. Bringmann’s lab at the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany. The lab moved to Marburg, Germany, in May 2019, where she since then conducts her research and finishes her PhD projects.
Florian Jordan works as an electronics technician for the electronics service at the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany. He finished his occasional training there in 2014 and since then he develops and repairs electrical equipment for research groups. In 2016 he received the CID certification, following this he started to study to become a state-certified technician.
Peleg Sapir was employed by the IT Service at the Max Planck for Biophysical Chemistry in Göttingen, Germany, during 2018. He is currently a PhD at the Max Planck Institute for Dynamics and Self-Organisation in Göttingen, Germany, focusing on control of spatiotemporal organization of cardiac fibrillation, in the Biomedical Physics Research Group of Prof. Stefan Luther. He received his bachelor degree in chemistry from Tel-Aviv University, Israel, in 2012 and his master’s degree in chemistry from the Free University of Berlin, Germany, in 2020, with the master’s thesis done under the supervision of Prof. Helmut Grubmüller in the department of Theoretical and Computational Biophysics at the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany.
Henrik Bringmann is a Professor at the University of Marburg, Germany, where he teaches Animal Physiology and investigates sleep in C. elegans. In 2007, he received his PhD in Cell Biology at the Max Planck Institute for Cell Biology and Genetics in Dresden, Germany. After a postdoc at the MRC Laboratory of Molecular Biology in Cambridge, UK, in 2009 he became a Max Planck Research Group Leader at the Max Planck Institute for Biophysical Chemistry in Göttingen. Since 2018 he is a full Professor at the University of Marburg.