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Parasram K, Bachetti D, Carmona-Alcocer V, Karpowicz P. Fluorescent Reporters for Studying Circadian Rhythms in Drosophila melanogaster. Methods Mol Biol 2022; 2482:353-371. [PMID: 35610439 DOI: 10.1007/978-1-0716-2249-0_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Circadian rhythms are daily oscillations in physiology and gene expression that are governed by a molecular feedback loop known as the circadian clock. In Drosophila melanogaster, the core clock consists of transcription factors clock (Clk) and cycle (cyc) which form protein heterodimers that activate transcription of their repressors, period (per) and timeless (tim). Once produced, protein heterodimers of per/tim repress Clk/cyc activity. One cycle of activation and repression takes approximately ("circa") 24-h ("diem") and repeats even in the absence of external stimuli. The circadian clock is active in many cells throughout the body; however, tracking it dynamically represents a challenge. Traditional fluorescent reporters are slowly degraded and consequently cannot be used to assess dynamic temporal changes exhibited by the circadian clock. The use of rapidly degraded fluorescent protein reporters containing destabilized GFP (dGFP) that report transcriptional activity in vivo at a single-cell level with ~1-h temporal resolution can circumvent this problem. Here we describe the use of circadian clock reporter strains of Drosophila melanogaster, ClockPER and ClockTIM, to track clock transcriptional activity using the intestine as a tissue of interest. These methods may be extended to other tissues in the body.
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Affiliation(s)
- Kathyani Parasram
- Department of Biomedical Sciences, University of Windsor, Windsor, ON, Canada
| | - Daniela Bachetti
- Department of Biomedical Sciences, University of Windsor, Windsor, ON, Canada
| | | | - Phillip Karpowicz
- Department of Biomedical Sciences, University of Windsor, Windsor, ON, Canada.
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Breitenbach T, Helfrich-Förster C, Dandekar T. An effective model of endogenous clocks and external stimuli determining circadian rhythms. Sci Rep 2021; 11:16165. [PMID: 34373483 PMCID: PMC8352901 DOI: 10.1038/s41598-021-95391-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
Circadian endogenous clocks of eukaryotic organisms are an established and rapidly developing research field. To investigate and simulate in an effective model the effect of external stimuli on such clocks and their components we developed a software framework for download and simulation. The application is useful to understand the different involved effects in a mathematical simple and effective model. This concerns the effects of Zeitgebers, feedback loops and further modifying components. We start from a known mathematical oscillator model, which is based on experimental molecular findings. This is extended with an effective framework that includes the impact of external stimuli on the circadian oscillations including high dose pharmacological treatment. In particular, the external stimuli framework defines a systematic procedure by input-output-interfaces to couple different oscillators. The framework is validated by providing phase response curves and ranges of entrainment. Furthermore, Aschoffs rule is computationally investigated. It is shown how the external stimuli framework can be used to study biological effects like points of singularity or oscillators integrating different signals at once. The mathematical framework and formalism is generic and allows to study in general the effect of external stimuli on oscillators and other biological processes. For an easy replication of each numerical experiment presented in this work and an easy implementation of the framework the corresponding Mathematica files are fully made available. They can be downloaded at the following link: https://www.biozentrum.uni-wuerzburg.de/bioinfo/computing/circadian/ .
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Affiliation(s)
- Tim Breitenbach
- grid.8379.50000 0001 1958 8658Institut für Mathematik, Universität Würzburg, Emil-Fischer-Strasse 30, 97074 Würzburg, Germany
| | | | - Thomas Dandekar
- grid.8379.50000 0001 1958 8658Biozentrum, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Davidian D, Ziman B, Escobar AL, Oviedo NJ. Direct Current Electric Stimulation Alters the Frequency and the Distribution of Mitotic Cells in Planarians. Bioelectricity 2021; 3:77-91. [PMID: 34476379 DOI: 10.1089/bioe.2020.0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Background: The use of direct current electric stimulation (DCS) is an effective strategy to treat disease and enhance body functionality. Thus, treatment with DCS is an attractive biomedical alternative, but the molecular underpinnings remain mostly unknown. The lack of experimental models to dissect the effects of DCS from molecular to organismal levels is an important caveat. Here, we introduce the planarian flatworm Schmidtea mediterranea as a tractable organism for in vivo studies of DCS. We developed an experimental method that facilitates the application of direct current electrical stimulation to the whole planarian body (pDCS). Materials and Methods: Planarian immobilization was achieved by combining treatment with anesthesia, agar embedding, and low temperature via a dedicated thermoelectric cooling unit. Electric currents for pDCS were delivered using pulled glass microelectrodes. The electric potential was supplied through a constant voltage power supply. pDCS was administered up to six hours, and behavioral and molecular effects were measured by using video recordings, immunohistochemistry, and gene expression analysis. Results: The behavioral immobilization effects are reversible, and pDCS resulted in a redistribution of mitotic cells along the mediolateral axis of the planarian body. The pDCS effects were dependent on the polarity of the electric field, which led to either increase in reductions in mitotic densities associated with the time of pDCS. The changes in mitotic cells were consistent with apparent redistribution in gene expression of the stem cell marker smedwi-1. Conclusion: The immobilization technique presented in this work facilitates studies aimed at dissecting the effects of exogenous electric stimulation in the adult body. Treatment with DCS can be administered for varying times, and the consequences evaluated at different levels, including animal behavior, cellular and transcriptional changes. Indeed, treatment with pDCS can alter cellular and transcriptional parameters depending on the polarity of the electric field and duration of the exposure.
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Affiliation(s)
- Devon Davidian
- Department of Molecular & Cell Biology and University of California Merced, Merced, California, USA
| | - Benjamin Ziman
- Department of Molecular & Cell Biology and University of California Merced, Merced, California, USA
| | - Ariel L Escobar
- Department of Bioengineering, University of California Merced, Merced, California, USA
| | - Néstor J Oviedo
- Department of Molecular & Cell Biology and University of California Merced, Merced, California, USA
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Liou NF, Lin SH, Chen YJ, Tsai KT, Yang CJ, Lin TY, Wu TH, Lin HJ, Chen YT, Gohl DM, Silies M, Chou YH. Diverse populations of local interneurons integrate into the Drosophila adult olfactory circuit. Nat Commun 2018; 9:2232. [PMID: 29884811 PMCID: PMC5993751 DOI: 10.1038/s41467-018-04675-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/14/2018] [Indexed: 11/09/2022] Open
Abstract
Drosophila olfactory local interneurons (LNs) in the antennal lobe are highly diverse and variable. How and when distinct types of LNs emerge, differentiate, and integrate into the olfactory circuit is unknown. Through systematic developmental analyses, we found that LNs are recruited to the adult olfactory circuit in three groups. Group 1 LNs are residual larval LNs. Group 2 are adult-specific LNs that emerge before cognate sensory and projection neurons establish synaptic specificity, and Group 3 LNs emerge after synaptic specificity is established. Group 1 larval LNs are selectively reintegrated into the adult circuit through pruning and re-extension of processes to distinct regions of the antennal lobe, while others die during metamorphosis. Precise temporal control of this pruning and cell death shapes the global organization of the adult antennal lobe. Our findings provide a road map to understand how LNs develop and contribute to constructing the olfactory circuit. Local interneurons (LNs) in the Drosophila olfactory system are highly diverse. Here, the authors labeled different LN types and described how different LN subtypes are integrated into the developing circuit.
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Affiliation(s)
- Nan-Fu Liou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Shih-Han Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ying-Jun Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Kuo-Ting Tsai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chi-Jen Yang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzi-Yang Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter, Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Ting-Han Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Ju Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yuh-Tarng Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Daryl M Gohl
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.,University of Minnesota Genomics Center, 1-210 CCRB, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Marion Silies
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.,European Neuroscience Institute, University Medical Center Göttingen, Grisebachstr. 5, 37077, Göttingen, Germany
| | - Ya-Hui Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan. .,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, 11529, Taiwan.
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Ishimoto H, Sano H. Ex Vivo Calcium Imaging for Visualizing Brain Responses to Endocrine Signaling in Drosophila. J Vis Exp 2018. [PMID: 29912190 DOI: 10.3791/57701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Organ-to-organ communication by endocrine signaling, for example, from the periphery to the brain, is essential for maintaining homeostasis. As a model animal for endocrine research, Drosophila melanogaster, which has sophisticated genetic tools and genome information, is being increasingly used. This article describes a method for the calcium imaging of Drosophila brain explants. This method enables the detection of the direct signaling of a hormone to the brain. It is well known that many peptide hormones act through G-protein-coupled receptors (GPCRs), whose activation causes an increase in the intracellular Ca2+concentration. Neural activation also elevates intracellular Ca2+ levels, from both Ca2+ influx and the release of Ca2+ stored in the endoplasmic reticulum (ER). A calcium sensor, GCaMP, can monitor these Ca2+ changes. In this method, GCaMP is expressed in the neurons of interest, and the GCaMP-expressing larval brain is dissected and cultured ex vivo. The test peptide is then applied to the brain explant, and the fluorescent changes in GCaMP are detected using a spinning disc confocal microscope equipped with a CCD camera. Using this method, any water-soluble molecule can be tested, and various cellular events associated with neural activation can be imaged using the appropriate fluorescent indicators. Moreover, by modifying the imaging chamber, this method can be used to image other Drosophila organs or the organs of other animals.
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Affiliation(s)
- Hiroshi Ishimoto
- Division of Biological Science, Graduate School of Science, Nagoya University
| | - Hiroko Sano
- Department of Molecular Genetics, Institute of Life Science, Kurume University;
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