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Hüppe L, Bahlburg D, Busack M, Lemburg J, Payton L, Reinhard N, Rieger D, Helfrich-Förster C, Meyer B. A new Activity Monitor for Aquatic Zooplankter (AMAZE) allows the recording of swimming activity in wild-caught Antarctic krill (Euphausia superba). Sci Rep 2024; 14:16963. [PMID: 39043920 PMCID: PMC11266396 DOI: 10.1038/s41598-024-67999-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 07/18/2024] [Indexed: 07/25/2024] Open
Abstract
Antarctic krill (Euphausia superba, hereafter krill) is a pelagic living crustacean and a key species in the Southern Ocean ecosystem. Krill builds up a huge biomass and its synchronized behavioral patterns, such as diel vertical migration (DVM), substantially impact ecosystem structure and carbon sequestration. However, the mechanistic basis of krill DVM is unknown and previous studies of krill behavior in the laboratory were challenged by complex behavior and large variability. Using a new experimental set-up, we recorded the swimming activity of individual wild-caught krill under light-dark cycles. Krill individuals exhibited differential phototactic responses to the light regime provided. However, using a new activity metric, we showed for the first time a consistent nocturnal increase in krill swimming activity in a controlled environment. Krill swimming activity in the new set-up was strongly synchronized with the light-dark cycle, similar to the diel vertical migration pattern of krill in the field when the krill were sampled for the experiment, demonstrated by hydroacoustic recordings. The new set-up presents a promising tool for investigating the mechanisms underlying krill behavioral patterns, which will increase our understanding of ecological interactions, the spatial distribution of populations, and their effects on biogeochemical cycles in the future.
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Affiliation(s)
- Lukas Hüppe
- Neurobiology and Genetics, University of Würzburg, Biocentre, Theodor-Boveri-Institute, Am Hubland, 97074, Würzburg, Germany.
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
| | - Dominik Bahlburg
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Michael Busack
- Section Deep-Sea Ecology and Technology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Johannes Lemburg
- Scientific Workshop, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Laura Payton
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
- CNRS, INP, EPOC, UMR 5805, University of Bordeaux, 33120, Arcachon, Bordeaux, France
| | - Nils Reinhard
- Neurobiology and Genetics, University of Würzburg, Biocentre, Theodor-Boveri-Institute, Am Hubland, 97074, Würzburg, Germany
| | - Dirk Rieger
- Neurobiology and Genetics, University of Würzburg, Biocentre, Theodor-Boveri-Institute, Am Hubland, 97074, Würzburg, Germany
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, University of Würzburg, Biocentre, Theodor-Boveri-Institute, Am Hubland, 97074, Würzburg, Germany
| | - Bettina Meyer
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Carl-Von-Ossietzky-Straße 9-11, 26111, Oldenburg, Germany.
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstrasse 231, 26129, Oldenburg, Germany.
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Abe S, Takahata Y, Miyakawa H. Daphnia uses its circadian clock for short-day recognition in environmental sex determination. Curr Biol 2024; 34:2002-2010.e3. [PMID: 38579713 DOI: 10.1016/j.cub.2024.03.027] [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] [Received: 11/09/2023] [Revised: 02/12/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
Some organisms have developed a mechanism called environmental sex determination (ESD), which allows environmental cues, rather than sex chromosomes or genes, to determine offspring sex.1,2,3,4 ESD is advantageous to optimize sex ratios according to environmental conditions, enhancing reproductive success.5,6 However, the process by which organisms perceive and translate diverse environmental signals into offspring sex remains unclear. Here, we analyzed the environmental perception mechanism in the crustacean, Daphnia pulex, a seasonal (photoperiodic) ESD arthropod, capable of producing females under long days and males under short days.7,8,9,10 Through breeding experiments, we found that their circadian clock likely contributes to perception of day length. To explore this further, we created a genetically modified daphnid by knocking out the clock gene, period, using genome editing. Knockout disrupted the daphnid's ability to sustain diel vertical migration (DVM) under constant darkness, driven by the circadian clock, and leading them to produce females regardless of day length. Additionally, when exposed to an analog of juvenile hormone (JH), an endocrine factor synthesized in mothers during male production, or subjected to unfavorable conditions of high density and low food availability, these knockout daphnids produced males regardless of day length, like wild-type daphnids. Based on these findings, we propose that recognizing short days via the circadian clock is the initial step in sex determination. This recognition subsequently triggers male production by signaling the endocrine system, specifically via the JH signal. Establishment of a connection between these two processes may be the crucial element in evolution of ESD in Daphnia.
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Affiliation(s)
- Shione Abe
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan
| | - Yugo Takahata
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan
| | - Hitoshi Miyakawa
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan.
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3
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Kwiatkowski ER, Rosenthal JJC, Emery P. Clocks at sea: the genome-editing tide is rising. Trends Genet 2024; 40:387-397. [PMID: 38336520 DOI: 10.1016/j.tig.2024.01.006] [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] [Received: 11/09/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024]
Abstract
The coastline is a particularly challenging environment for its inhabitants. Not only do they have to cope with the solar day and the passing of seasons, but they must also deal with tides. In addition, many marine species track the phase of the moon, especially to coordinate reproduction. Marine animals show remarkable behavioral and physiological adaptability, using biological clocks to anticipate specific environmental cycles. Presently, we lack a basic understanding of the molecular mechanisms underlying circatidal and circalunar clocks. Recent advances in genome engineering and the development of genetically tractable marine model organisms are transforming how we study these timekeeping mechanisms and opening a novel era in marine chronobiology.
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Affiliation(s)
- Erica R Kwiatkowski
- University of Massachusetts Chan Medical School, Department of Neurobiology, Worcester, MA 01605, USA
| | | | - Patrick Emery
- University of Massachusetts Chan Medical School, Department of Neurobiology, Worcester, MA 01605, USA.
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4
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Yokomizo T, Takahashi Y. Plasticity of circadian and circatidal rhythms in activity and transcriptomic dynamics in a freshwater snail. Heredity (Edinb) 2024; 132:267-274. [PMID: 38538720 DOI: 10.1038/s41437-024-00680-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 05/08/2024] Open
Abstract
Organisms have diverse biological clocks synchronised with environmental cycles depending on their habitats. Anticipation of tidal changes has driven the evolution of circatidal rhythms in some marine species. In the freshwater snail, Semisulcospira reiniana, individuals in nontidal areas exhibit circadian rhythms, whereas those in tidal areas exhibit both circadian and circatidal rhythms. We investigated whether the circatidal rhythms are genetically determined or induced by environmental cycles. The exposure to a simulated tidal cycle did not change the intensity of circatidal rhythm in individuals in the nontidal population. However, snails in the tidal population showed different activity rhythms depending on the presence or absence of the exposure. Transcriptome analysis revealed that genes with circatidal oscillation increased due to entrainment to the tidal cycle in both populations and dominant rhythmicity was consistent with the environmental cycle. These results suggest plasticity in the endogenous rhythm in the gene expression in both populations. Note that circatidal oscillating genes were more abundant in the tidal population than in the nontidal population, suggesting that a greater number of genes are associated with circatidal clocks in the tidal population compared to the nontidal population. This increase of circatidal clock-controlled genes in the tidal population could be caused by genetic changes in the biological clock or the experience of tidal cycle in the early life stage. Our findings suggest that the plasticity of biological rhythms may have contributed to the adaptation to the tidal environment in S. reiniana.
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Affiliation(s)
- Takumi Yokomizo
- Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Yuma Takahashi
- Graduate School of Science, Chiba University, Chiba, 263-8522, Japan.
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Chiu JC. Editorial: Rising stars in chronobiology 2022. Front Physiol 2024; 15:1412956. [PMID: 38725565 PMCID: PMC11079284 DOI: 10.3389/fphys.2024.1412956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 04/11/2024] [Indexed: 05/12/2024] Open
Affiliation(s)
- Joanna C. Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, CA, United States
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Chawla S, O’Neill J, Knight MI, He Y, Wang L, Maronde E, Rodríguez SG, van Ooijen G, Garbarino-Pico E, Wolf E, Dkhissi-Benyahya O, Nikhat A, Chakrabarti S, Youngstedt SD, Zi-Ching Mak N, Provencio I, Oster H, Goel N, Caba M, Oosthuizen M, Duffield GE, Chabot C, Davis SJ. Timely Questions Emerging in Chronobiology: The Circadian Clock Keeps on Ticking. J Circadian Rhythms 2024; 22:2. [PMID: 38617710 PMCID: PMC11011957 DOI: 10.5334/jcr.237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 04/16/2024] Open
Abstract
Chronobiology investigations have revealed much about cellular and physiological clockworks but we are far from having a complete mechanistic understanding of the physiological and ecological implications. Here we present some unresolved questions in circadian biology research as posed by the editorial staff and guest contributors to the Journal of Circadian Rhythms. This collection of ideas is not meant to be comprehensive but does reveal the breadth of our observations on emerging trends in chronobiology and circadian biology. It is amazing what could be achieved with various expected innovations in technologies, techniques, and mathematical tools that are being developed. We fully expect strengthening mechanistic work will be linked to health care and environmental understandings of circadian function. Now that most clock genes are known, linking these to physiological, metabolic, and developmental traits requires investigations from the single molecule to the terrestrial ecological scales. Real answers are expected for these questions over the next decade. Where are the circadian clocks at a cellular level? How are clocks coupled cellularly to generate organism level outcomes? How do communities of circadian organisms rhythmically interact with each other? In what way does the natural genetic variation in populations sculpt community behaviors? How will methods development for circadian research be used in disparate academic and commercial endeavors? These and other questions make it a very exciting time to be working as a chronobiologist.
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Affiliation(s)
| | - John O’Neill
- MRC Laboratory of Molecular Biology Cambridge, UK
| | | | - Yuqing He
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, China National Botanical Garden, Beijing 100093, CN
| | - Lei Wang
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, China National Botanical Garden, Beijing 100093, CN
| | - Erik Maronde
- Institut für Anatomie II, Dr. Senckenbergische Anatomie, Goethe-Universität Frankfurt, Theodor-Stern-Kai-7, 60590 Frankfurt, DE
| | - Sergio Gil Rodríguez
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Eduardo Garbarino-Pico
- Universidad Nacional de Córdoba (UNC), Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Córdoba, AR
- CONICET-UNC, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Córdoba, AR
| | - Eva Wolf
- Institute of Molecular Physiology (IMP), Johannes Gutenberg-University Mainz, Hanns-Dieter-Hüsch- Weg 17, 55128 Mainz, DE
| | - Ouria Dkhissi-Benyahya
- Inserm, Stem Cell and Brain Research Institute U1208, Univ Lyon, UniversitéClaude Bernard Lyon 1, 18 Avenue du Doyen Lépine, 69500, Bron, FR
| | - Anjoom Nikhat
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Bangalore, Karnataka 560065, IN
| | - Shaon Chakrabarti
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Bangalore, Karnataka 560065, IN
| | - Shawn D. Youngstedt
- Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, US
- Department of Medicine, University of Arizona, Tucson, AZ, US
| | | | - Ignacio Provencio
- Department of Biology and Department of Ophthalmology, University of Virginia, Charlottesville, VA, US
| | - Henrik Oster
- Institute of Neurobiology, Center for Brain, Behavior & Metabolism (CBBM), University of Luebeck, 23562 Luebeck, DE
| | - Namni Goel
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, US
| | - Mario Caba
- Centro de Investigaciones Biomédicas, Universidad Veracruzana, Xalapa, Ver., MX
| | - Maria Oosthuizen
- Department of Zoology and Entomology, University of Pretoria, Pretoria, ZA
- Mammal Research Institute, University of Pretoria, Hatfield, ZA
| | - Giles E. Duffield
- Department of Biological Sciences, Galvin Life Science Center, University of Notre Dame, Notre Dame, US
| | - Christopher Chabot
- Department of Biological Sciences, Plymouth State University, Plymouth, NH 03264, US
| | - Seth J. Davis
- Department of Biology, University of York, York YO105DD, UK
- State Key Laboratory of Crop Stress Biology, School of Life Sciences, Henan University, Kaifeng 475004, CN
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Lin Z, Green EW, Webster SG, Hastings MH, Wilcockson DC, Kyriacou CP. The circadian clock gene bmal1 is necessary for co-ordinated circatidal rhythms in the marine isopod Eurydice pulchra (Leach). PLoS Genet 2023; 19:e1011011. [PMID: 37856540 PMCID: PMC10617734 DOI: 10.1371/journal.pgen.1011011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 10/31/2023] [Accepted: 10/09/2023] [Indexed: 10/21/2023] Open
Abstract
Circadian clocks in terrestrial animals are encoded by molecular feedback loops involving the negative regulators PERIOD, TIMELESS or CRYPTOCHROME2 and positive transcription factors CLOCK and BMAL1/CYCLE. The molecular basis of circatidal (~12.4 hour) or other lunar-mediated cycles (~15 day, ~29 day), widely expressed in coastal organisms, is unknown. Disrupting circadian clockworks does not appear to affect lunar-based rhythms in several organisms that inhabit the shoreline suggesting a molecular independence of the two cycles. Nevertheless, pharmacological inhibition of casein kinase 1 (CK1) that targets PERIOD stability in mammals and flies, affects both circadian and circatidal phenotypes in Eurydice pulchra (Ep), the speckled sea-louse. Here we show that these drug inhibitors of CK1 also affect the phosphorylation of EpCLK and EpBMAL1 and disrupt EpCLK-BMAL1-mediated transcription in Drosophila S2 cells, revealing a potential link between these two positive circadian regulators and circatidal behaviour. We therefore performed dsRNAi knockdown of Epbmal1 as well as the major negative regulator in Eurydice, Epcry2 in animals taken from the wild. Epcry2 and Epbmal1 knockdown disrupted Eurydice's circadian phenotypes of chromatophore dispersion, tim mRNA cycling and the circadian modulation of circatidal swimming, as expected. However, circatidal behaviour was particularly sensitive to Epbmal1 knockdown with consistent effects on the power, amplitude and rhythmicity of the circatidal swimming cycle. Thus, three Eurydice negative circadian regulators, EpCRY2, in addition to EpPER and EpTIM (from a previous study), do not appear to be required for the expression of robust circatidal behaviour, in contrast to the positive regulator EpBMAL1. We suggest a neurogenetic model whereby the positive circadian regulators EpBMAL1-CLK are shared between circadian and circatidal mechanisms in Eurydice but circatidal rhythms require a novel, as yet unknown negative regulator.
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Affiliation(s)
- Zhang Lin
- Department of Genetics & Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Edward W. Green
- German Cancer Research Center, Heidelberg, Baden-Württemberg, Germany
| | - Simon G. Webster
- School of Biological Sciences, Bangor University, Bangor, United Kingdom
| | | | - David C. Wilcockson
- Department of Life Sciences, Aberystwyth University, Aberystwyth, United Kingdom
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Abstract
The molecular nature of the biological timer used by organisms living in the marine intertidal zone to anticipate wide variations in environmental conditions caused by the tides has remained elusive. A new study reveals that the circadian clock gene bmal1 is required for circatidal rhythms.
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Affiliation(s)
- Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77845, USA.
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