1
|
Maas AE, Timmins-Schiffman E, Tarrant AM, Nunn BL, Park J, Blanco-Bercial L. Diel metabolic patterns revealed by in situ transcriptome and proteome in a vertically migratory copepod. Mol Ecol 2024; 33:e17284. [PMID: 38258354 DOI: 10.1111/mec.17284] [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: 08/02/2022] [Revised: 12/06/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024]
Abstract
Zooplankton undergo a diel vertical migration (DVM) which exposes them to gradients of light, temperature, oxygen, and food availability on a predictable daily schedule. Disentangling the co-varying and potentially synergistic interactions on metabolic rates has proven difficult, despite the importance of this migration for the delivery of metabolic waste products to the distinctly different daytime (deep) and nighttime (surface) habitats. This study examines the transcriptomic and proteomic profiles of the circumglobal migratory copepod, Pleuromamma xiphias, over the diel cycle. The transcriptome showed that 96% of differentially expressed genes were upregulated during the middle of the day - the period often considered to be of lowest zooplankton activity. The changes in protein abundance were more spread out over time, peaking (42% of comparisons) in the early evening. Between 9:00 and 15:00, both the transcriptome and proteome datasets showed increased expression related to chitin synthesis and degradation. Additionally, at 09:00 and 22:00, there were increases in myosin and vitellogenin proteins, potentially linked to the stress of migration and/or reproductive investment. Based on protein abundances detected, there is an inferred switch in broad metabolic processes, shifting from electron transport system in the day to glycolysis and glycogen mobilization in the afternoon/evening. These observations provide evidence of the diel impact of DVM on transcriptomic and proteomic pathways that likely influence metabolic processes and subsequent excretion products, and clarify how this behaviour results in the direct rapid transport of waste metabolites from the surface to the deep ocean.
Collapse
Affiliation(s)
- Amy E Maas
- Bermuda Institute of Ocean Sciences, School of Ocean Futures, Arizona State University, St. George's, Bermuda
| | | | - Ann M Tarrant
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Brook L Nunn
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Jea Park
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Leocadio Blanco-Bercial
- Bermuda Institute of Ocean Sciences, School of Ocean Futures, Arizona State University, St. George's, Bermuda
| |
Collapse
|
2
|
Bahlburg D, Hüppe L, Böhrer T, Thorpe SE, Murphy EJ, Berger U, Meyer B. Plasticity and seasonality of the vertical migration behaviour of Antarctic krill using acoustic data from fishing vessels. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230520. [PMID: 37771962 PMCID: PMC10523065 DOI: 10.1098/rsos.230520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/06/2023] [Indexed: 09/30/2023]
Abstract
Understanding the vertical migration behaviour of Antarctic krill is important for understanding spatial distribution, ecophysiology, trophic interactions and carbon fluxes of this Southern Ocean key species. In this study, we analysed an eight-month continuous dataset recorded with an ES80 echosounder on board a commercial krill fishing vessel in the southwest Atlantic sector of the Southern Ocean. Our analysis supports the existing hypothesis that krill swarms migrate into deeper waters during winter but also reveals a high degree of variability in vertical migration behaviour within seasons, even at small spatial scales. During summer, we found that behaviour associated with prolonged surface presence primarily occurred at low surface chlorophyll a concentrations whereas multiple ascent-descent cycles per day occurred when surface chlorophyll a concentrations were elevated. The high plasticity, with some krill swarms behaving differently in the same location at the same time, suggests that krill behaviour is not a purely environmentally driven process. Differences in life stage, physiology and type of predator are likely other important drivers. Finally, our study demonstrates new ways of using data from krill fishing vessels, and with the routine collection of additional information in potential future projects, they have great potential to significantly advance our understanding of krill ecology.
Collapse
Affiliation(s)
- Dominik Bahlburg
- Forstliche Biometrie und Systemanalyse, Technische Universität Dresden, Pienner Straße 8, 01737 Tharandt, Dresden, Germany
- Helmholtz Centre for Environmental Research Leipzig, Permoserstraße 15, 04318 Leipzig, Germany
| | - Lukas Hüppe
- Neurobiology and Genetics, Julius-Maximilian-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Thomas Böhrer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Schloßplatz 4, 91054 Erlangen, Germany
| | - Sally E. Thorpe
- Ecosystems, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Eugene J. Murphy
- Ecosystems, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Uta Berger
- Forstliche Biometrie und Systemanalyse, Technische Universität Dresden, Pienner Straße 8, 01737 Tharandt, Dresden, Germany
| | - Bettina Meyer
- Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity, Ammerländer Heerstraße 231, 26129 Oldenburg, Germany
| |
Collapse
|
3
|
Cheng CHC, Rivera-Colón AG, Minhas BF, Wilson L, Rayamajhi N, Vargas-Chacoff L, Catchen JM. Chromosome-Level Genome Assembly and Circadian Gene Repertoire of the Patagonia Blennie Eleginops maclovinus-The Closest Ancestral Proxy of Antarctic Cryonotothenioids. Genes (Basel) 2023; 14:1196. [PMID: 37372376 DOI: 10.3390/genes14061196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
The basal South American notothenioid Eleginops maclovinus (Patagonia blennie or róbalo) occupies a uniquely important phylogenetic position in Notothenioidei as the singular closest sister species to the Antarctic cryonotothenioid fishes. Its genome and the traits encoded therein would be the nearest representatives of the temperate ancestor from which the Antarctic clade arose, providing an ancestral reference for deducing polar derived changes. In this study, we generated a gene- and chromosome-complete assembly of the E. maclovinus genome using long read sequencing and HiC scaffolding. We compared its genome architecture with the more basally divergent Cottoperca gobio and the derived genomes of nine cryonotothenioids representing all five Antarctic families. We also reconstructed a notothenioid phylogeny using 2918 proteins of single-copy orthologous genes from these genomes that reaffirmed E. maclovinus' phylogenetic position. We additionally curated E. maclovinus' repertoire of circadian rhythm genes, ascertained their functionality by transcriptome sequencing, and compared its pattern of gene retention with C. gobio and the derived cryonotothenioids. Through reconstructing circadian gene trees, we also assessed the potential role of the retained genes in cryonotothenioids by referencing to the functions of the human orthologs. Our results found E. maclovinus to share greater conservation with the Antarctic clade, solidifying its evolutionary status as the direct sister and best suited ancestral proxy of cryonotothenioids. The high-quality genome of E. maclovinus will facilitate inquiries into cold derived traits in temperate to polar evolution, and conversely on the paths of readaptation to non-freezing habitats in various secondarily temperate cryonotothenioids through comparative genomic analyses.
Collapse
Affiliation(s)
- Chi-Hing Christina Cheng
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - Angel G Rivera-Colón
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - Bushra Fazal Minhas
- Informatics Program, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - Loralee Wilson
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - Niraj Rayamajhi
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - Luis Vargas-Chacoff
- Laboratorio de Fisiología de Peces, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia 5090000, Chile
- Centro Fondap de Investigación de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia 5090000, Chile
- Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Universidad Austral de Chile, Valdivia 5090000, Chile
| | - Julian M Catchen
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL 61801, USA
| |
Collapse
|
4
|
Häfker NS, Andreatta G, Manzotti A, Falciatore A, Raible F, Tessmar-Raible K. Rhythms and Clocks in Marine Organisms. ANNUAL REVIEW OF MARINE SCIENCE 2023; 15:509-538. [PMID: 36028229 DOI: 10.1146/annurev-marine-030422-113038] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The regular movements of waves and tides are obvious representations of the oceans' rhythmicity. But the rhythms of marine life span across ecological niches and timescales, including short (in the range of hours) and long (in the range of days and months) periods. These rhythms regulate the physiology and behavior of individuals, as well as their interactions with each other and with the environment. This review highlights examples of rhythmicity in marine animals and algae that represent important groups of marine life across different habitats. The examples cover ecologically highly relevant species and a growing number of laboratory model systems that are used to disentangle key mechanistic principles. The review introduces fundamental concepts of chronobiology, such as the distinction between rhythmic and endogenous oscillator-driven processes. It also addresses the relevance of studying diverse rhythms and oscillators, as well as their interconnection, for making better predictions of how species will respond to environmental perturbations, including climate change. As the review aims to address scientists from the diverse fields of marine biology, ecology, and molecular chronobiology, all of which have their own scientific terms, we provide definitions of key terms throughout the article.
Collapse
Affiliation(s)
- N Sören Häfker
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria; ,
- Research Platform "Rhythms of Life," University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Gabriele Andreatta
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria; ,
- Research Platform "Rhythms of Life," University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Alessandro Manzotti
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière chez les Microalgues, UMR 7141, CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris, France;
| | - Angela Falciatore
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière chez les Microalgues, UMR 7141, CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris, France;
| | - Florian Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria; ,
- Research Platform "Rhythms of Life," University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Kristin Tessmar-Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria; ,
- Research Platform "Rhythms of Life," University of Vienna, Vienna BioCenter, Vienna, Austria
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| |
Collapse
|
5
|
Eggebo J, Groß J, Bengtson Nash S. Interpretation of southern hemisphere humpback whale diet via stable isotopes; implications of tissue-specific analysis. PLoS One 2023; 18:e0283330. [PMID: 37011067 PMCID: PMC10069779 DOI: 10.1371/journal.pone.0283330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 03/07/2023] [Indexed: 04/05/2023] Open
Abstract
Blubber and skin are commonly used tissues in stable isotope analysis for the purpose of investigating cetacean diet. Critical comparison of tissue-specific isotopic signals is, however, lacking resulting in uncertainty surrounding the representativeness and therefore utility of different tissues for accurate determination of recent foraging. This study used remotely biopsied blubber and skin tissues from southern hemisphere humpback whales for strategic comparison of δ13C and δ15N values. Samples were collected between 2008-2018 as part of long-term monitoring under the Humpback Whale Sentinel Program. Blubber tissues were lipid-extracted prior to analysis, whilst mathematical lipid-correction was performed on skin samples. Isotopic values from paired blubber and skin samples from the same individuals were compared to assess whether tissues could be used interchangeably for isotope analysis and dietary interpretation. Significant differences were observed for both δ13C and δ15N, flagging previously undocumented methodological considerations, and the need for method validation and standardisation in application of these approaches. This study therefore advances methodological aspects of cetacean dietary analysis. This is of elevated importance in the context of rapidly changing ocean ecosystems.
Collapse
Affiliation(s)
- June Eggebo
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Jasmin Groß
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Susan Bengtson Nash
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
| |
Collapse
|
6
|
Cremer R, Wacker A, Schwarzenberger A. More Light Please: Daphnia Benefit From Light Pollution by Increased Tolerance Toward Cyanobacterial Chymotrypsin Inhibitors. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.834422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cryptochromes are evolutionary ancient blue-light photoreceptors that are part of the circadian clock in the nervous system of many organisms. Cryptochromes transfer information of the predominant light regime to the clock which results in the fast adjustment to photoperiod. Therefore, the clock is sensitive to light changes and can be affected by anthropogenic Artificial Light At Night (ALAN). This in turn has consequences for clock associated behavioral processes, e.g., diel vertical migration (DVM) of zooplankton. In freshwater ecosystems, the zooplankton genus Daphnia performs DVM in order to escape optically hunting predators and to avoid UV light. Concomitantly, Daphnia experience circadian changes in food-supply during DVM. Daphnia play the keystone role in the carbon-transfer to the next trophic level. Therefore, the whole ecosystem is affected during the occurrence of cyanobacteria blooms as cyanobacteria reduce food quality due to their production of digestive inhibitors (e.g., protease inhibitors). In other organisms, digestion is linked to the circadian clock. If this is also the case for Daphnia, the expression of protease genes should show a rhythmic expression following circadian expression of clock genes (e.g., cryptochrome 2). We tested this hypothesis and demonstrated that gene expression of the clock and of proteases was affected by ALAN. Contrary to our expectations, the activity of one type of proteases (chymotrypsins) was increased by ALAN. This indicates that higher protease activity might improve the diet utilization. Therefore, we treated D. magna with a chymotrypsin-inhibitor producing cyanobacterium and found that ALAN actually led to an increase in Daphnia’s growth rate in comparison to growth on the same cyanobacterium in control light conditions. We conclude that this increased tolerance to protease inhibitors putatively enables Daphnia populations to better control cyanobacterial blooms that produce chymotrypsin inhibitors in the Anthropocene, which is defined by light pollution and by an increase of cyanobacterial blooms due to eutrophication.
Collapse
|
7
|
Michael K, Suberg LA, Wessels W, Kawaguchi S, Meyer B. Facing Southern Ocean warming: Temperature effects on whole animal performance of Antarctic krill (Euphausia superba). ZOOLOGY 2021; 146:125910. [PMID: 33735797 DOI: 10.1016/j.zool.2021.125910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 10/22/2022]
Abstract
The ongoing environmental changes in the Southern Ocean may cause a dramatic decrease in habitat quality. Due to its central position in the food web, Antarctic krill (Euphausia superba) is a key species of the marine Antarctic ecosystem. It is therefore crucial to understand how increasing water temperatures affect important krill life-cycle processes. Here, a long-term (August - March) laboratory acclimation experiment at different temperature scenarios (0.5 °C, 1.5 °C, 2.5 °C, 3.5 °C, 5 °C, 7 °C) was performed and the effects of elevated temperatures on whole animal parameters (O2 consumption, body length, length of the digestive gland) were analyzed. The response of krill oxygen consumption to different experimental temperatures differed between acute/short-term and long-term acclimation. After 8 months, krill oxygen consumption remained unchanged up to temperatures of 3.5 °C and was significantly higher at temperatures > 3.5 °C. Krill acclimated to temperatures ≥ 3.5 °C were significantly smaller at the end of the experiment. Limited food intake and/or conversion may have contributed to this effect, especially pronounced after the onset of the reproductive period. In addition, the seasonal growth pattern in males differed from that of females. Together, our findings indicate that warming Southern Ocean waters are likely to increase metabolic rate in krill, possibly altering the amount of energy available for other important life-cycle processes, a finding directly related to future population dynamics and fisheries management.
Collapse
Affiliation(s)
- Katharina Michael
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111, Oldenburg, Germany.
| | - Lavinia A Suberg
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Scientific Division Polar Biological Oceanography, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Wiebke Wessels
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111, Oldenburg, Germany
| | - So Kawaguchi
- Australian Antarctic Division, Department of Agriculture, Water and the Environment, 203 Channel Highway, Kingston, Tasmania, 7050, Australia; Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Hobart, Tasmania, 7000, Australia
| | - Bettina Meyer
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111, Oldenburg, Germany; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Scientific Division Polar Biological Oceanography, Am Handelshafen 12, 27570, Bremerhaven, Germany; Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany
| |
Collapse
|
8
|
Piccolin F, Pitzschler L, Biscontin A, Kawaguchi S, Meyer B. Circadian regulation of diel vertical migration (DVM) and metabolism in Antarctic krill Euphausia superba. Sci Rep 2020; 10:16796. [PMID: 33033314 PMCID: PMC7546626 DOI: 10.1038/s41598-020-73823-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 09/21/2020] [Indexed: 11/09/2022] Open
Abstract
Antarctic krill (Euphausia superba) are high latitude pelagic organisms which play a key ecological role in the ecosystem of the Southern Ocean. To synchronize their daily and seasonal life-traits with their highly rhythmic environment, krill rely on the implementation of rhythmic strategies which might be regulated by a circadian clock. A recent analysis of krill circadian transcriptome revealed that their clock might be characterized by an endogenous free-running period of about 12-15 h. Using krill exposed to simulated light/dark cycles (LD) and constant darkness (DD), we investigated the circadian regulation of krill diel vertical migration (DVM) and oxygen consumption, together with daily patterns of clock gene expression in brain and eyestalk tissue. In LD, we found clear 24 h rhythms of DVM and oxygen consumption, suggesting a synchronization with photoperiod. In DD, the DVM rhythm shifted to a 12 h period, while the peak of oxygen consumption displayed a temporal advance during the subjective light phase. This suggested that in free-running conditions the periodicity of these clock-regulated output functions might reflect the shortening of the endogenous period observed at the transcriptional level. Moreover, differences in the expression patterns of clock gene in brain and eyestalk, in LD and DD, suggested the presence in krill of a multiple oscillator system. Evidence of short periodicities in krill behavior and physiology further supports the hypothesis that a short endogenous period might represent a circadian adaption to cope with extreme seasonal photoperiodic variability at high latitude.
Collapse
Affiliation(s)
- Fabio Piccolin
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570, Bremerhaven, Germany.
| | - Lisa Pitzschler
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Alberto Biscontin
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35121, Padova, Italy
| | - So Kawaguchi
- Australian Antarctic Division, Department of the Environment and Energy, 203 Channel Hwy, Kingston, TAS, 7050, Australia
| | - Bettina Meyer
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, 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, Ammerländer Heerstrasse 231, 26129, Oldenburg, Germany.
| |
Collapse
|
9
|
Demographic and maturity patterns of Antarctic krill (Euphausia superba) in an overwintering hotspot. Polar Biol 2020. [DOI: 10.1007/s00300-020-02704-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
10
|
Analysis of the circadian transcriptome of the Antarctic krill Euphausia superba. Sci Rep 2019; 9:13894. [PMID: 31554872 PMCID: PMC6761102 DOI: 10.1038/s41598-019-50282-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 09/10/2019] [Indexed: 11/09/2022] Open
Abstract
Antarctic krill (Euphausia superba) is a high latitude pelagic organism which plays a central role in the Southern Ocean ecosystem. E. superba shows daily and seasonal rhythms in physiology and behaviour, which are synchronized with the environmental cycles of its habitat. Recently, the main components of the krill circadian machinery have been identified and characterized. However, the exact mechanisms through which the endogenous timing system operates the control and regulation of the overt rhythms remains only partially understood. Here we investigate the involvement of the circadian clock in the temporal orchestration of gene expression by using a newly developed version of a krill microarray platform. The analysis of transcriptome data from krill exposed to both light-dark cycles (LD 18:6) and constant darkness (DD), has led to the identification of 1,564 putative clock-controlled genes. A remarkably large proportion of such genes, including several clock components (clock, period, cry2, vrille, and slimb), show oscillatory expression patterns in DD, with a periodicity shorter than 24 hours. Energy-storage pathways appear to be regulated by the endogenous clock in accordance with their ecological relevance in daily energy managing and overwintering. Our results provide the first representation of the krill circadian transcriptome under laboratory, free-running conditions.
Collapse
|
11
|
Arboleda E, Zurl M, Waldherr M, Tessmar-Raible K. Differential Impacts of the Head on Platynereis dumerilii Peripheral Circadian Rhythms. Front Physiol 2019; 10:900. [PMID: 31354531 PMCID: PMC6638195 DOI: 10.3389/fphys.2019.00900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
The marine bristle worm Platynereis dumerilii is a useful functional model system for the study of the circadian clock and its interplay with others, e.g., circalunar clocks. The focus has so far been on the worm's head. However, behavioral and physiological cycles in other animals typically arise from the coordination of circadian clocks located in the brain and in peripheral tissues. Here, we focus on peripheral circadian rhythms and clocks, revisit and expand classical circadian work on the worm's chromatophores, investigate locomotion as read-out and include molecular analyses. We establish that different pieces of the trunk exhibit synchronized, robust oscillations of core circadian clock genes. These circadian core clock transcripts are under strong control of the light-dark cycle, quickly losing synchronized oscillation under constant darkness, irrespective of the absence or presence of heads. Different wavelengths are differently effective in controlling the peripheral molecular synchronization. We have previously shown that locomotor activity is under circadian clock control. Here, we show that upon decapitation worms exhibit strongly reduced activity levels. While still following the light-dark cycle, locomotor rhythmicity under constant darkness is less clear. We also observe the rhythmicity of pigments in the worm's individual chromatophores, confirming their circadian pattern. These size changes continue under constant darkness, but cannot be re-entrained by light upon decapitation. Our works thus provides the first basic characterization of the peripheral circadian clock of P. dumerilii. In the absence of the head, light is essential as a major synchronization cue for peripheral molecular and locomotor circadian rhythms, while circadian changes in chromatophore size can continue for several days in the absence of light/dark changes and the head. Thus, in Platynereis the dependence on the head depends on the type of peripheral rhythm studied. These data show that peripheral circadian rhythms and clocks should also be considered in "non-conventional" molecular model systems, i.e., outside Drosophila melanogaster, Danio rerio, and Mus musculus, and build a basic foundation for future investigations of interactions of clocks with different period lengths in marine organisms.
Collapse
Affiliation(s)
- Enrique Arboleda
- Max F. Perutz Laboratories, Vienna BioCenter, University of Vienna, Vienna, Austria
| | - Martin Zurl
- Max F. Perutz Laboratories, Vienna BioCenter, University of Vienna, Vienna, Austria
- Research Platform “Rhythms of Life”, Vienna BioCenter, University of Vienna, Vienna, Austria
| | - Monika Waldherr
- Max F. Perutz Laboratories, Vienna BioCenter, University of Vienna, Vienna, Austria
- Research Platform “Rhythms of Life”, Vienna BioCenter, University of Vienna, Vienna, Austria
| | - Kristin Tessmar-Raible
- Max F. Perutz Laboratories, Vienna BioCenter, University of Vienna, Vienna, Austria
- Research Platform “Rhythms of Life”, Vienna BioCenter, University of Vienna, Vienna, Austria
| |
Collapse
|
12
|
Piccolin F, Suberg L, King R, Kawaguchi S, Meyer B, Teschke M. The Seasonal Metabolic Activity Cycle of Antarctic Krill ( Euphausia superba): Evidence for a Role of Photoperiod in the Regulation of Endogenous Rhythmicity. Front Physiol 2018; 9:1715. [PMID: 30618779 PMCID: PMC6307472 DOI: 10.3389/fphys.2018.01715] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 11/15/2018] [Indexed: 11/19/2022] Open
Abstract
Antarctic krill (Euphausia superba), a key species in the Southern Ocean, reduce their metabolism as an energy saving mechanism in response to the harsh environmental conditions during the Antarctic winter. Although the adaptive significance of this seasonal metabolic shift seems obvious, the driving factors are still unclear. In particular, it is debated whether the seasonal metabolic cycle is driven by changes in food availability, or if an endogenous timing system entrained by photoperiod might be involved. In this study, we used different long-term photoperiodic simulations to examine the influence of light regime and endogenous rhythmicity on the regulation of krill seasonal metabolic cycle. Krill showed a seasonal cycle of growth characterized by null-to-negative growth rates during autumn-winter and positive growth rates during spring-summer, which was manifested also in constant darkness, indicating strong endogenous regulation. Similar endogenous cycles were observed for the activity of the key-metabolic enzyme malate dehydrogenase (MDH) and for the expression levels of a selection of metabolic-related genes, with higher values in spring-summer and lower values in autumn-winter. On the other side, a seasonal cycle of oxygen consumption was observed only when krill were exposed to simulated seasonal changes in photoperiod, indicating that light-related cues might play a major role in the regulation of krill oxygen consumption. The influence of light-regime on oxygen consumption was minimal during winter, when light-phase duration was below 8 h, and it was maximal during summer, when light-phase duration was above 16 h. Significant upregulation of the krill clock genes clk, cry2, and tim1, as well as of the circadian-related opsins rh1a and rrh, was observed after light-phase duration had started to decrease in early autumn, suggesting the presence of a signaling cascade linking specific seasonal changes in the Antarctic light regime with clock gene activity and the regulation of krill metabolic dormancy over the winter.
Collapse
Affiliation(s)
- Fabio Piccolin
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Lavinia Suberg
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Robert King
- Department of the Environment and Energy, Australian Antarctic Division, Kingston, TAS, Australia
| | - So Kawaguchi
- Department of the Environment and Energy, Australian Antarctic Division, Kingston, TAS, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, Battery Point, TAS, Australia
| | - Bettina Meyer
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), University of Oldenburg, Oldenburg, Germany
| | - Mathias Teschke
- Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| |
Collapse
|
13
|
Höring F, Teschke M, Suberg L, Kawaguchi S, Meyer B. Light regime affects the seasonal cycle of Antarctic krill (Euphausia superba): impacts on growth, feeding, lipid metabolism, and maturity. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0353] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Light regime is an important zeitgeber for Antarctic krill (Euphausia superba Dana, 1850), which seems to entrain an endogenous timing system that synchronizes its life cycle to the extreme light conditions in the Southern Ocean. To understand the flexibility of Antarctic krill’s seasonal cycle, we investigated its physiological and behavioural responses to different light regimes and if an endogenous timing system was involved in the regulation of these seasonal processes. We analysed growth, feeding, lipid content, and maturity in a 2-year laboratory experiment simulating the latitudinal light regimes at 52°S and 66°S and constant darkness under constant food level. Our results showed that light regime affected seasonal cycles of growth, feeding, lipid metabolism, and maturity in Antarctic krill. Seasonal patterns of growth, feeding, and maturity persisted under constant darkness, indicating the presence of an endogenous timing system. The maturity cycle showed differences in critical photoperiods according to the simulated latitudinal light regime. This suggests a flexible endogenous timing mechanism in Antarctic krill, which may determine its response to future environmental changes.
Collapse
Affiliation(s)
- Flavia Höring
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Carl von Ossietzky University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky-Str. 9-11, 26111 Oldenburg, Germany
| | - Mathias Teschke
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Lavinia Suberg
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - So Kawaguchi
- Australian Antarctic Division, Department of the Environment and Energy, Channel Highway, Kingston, Tasmania 7050, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia
| | - Bettina Meyer
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Carl von Ossietzky University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky-Str. 9-11, 26111 Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at the University of Oldenburg, 26111 Oldenburg, Germany
| |
Collapse
|
14
|
Maas AE, Blanco-Bercial L, Lo A, Tarrant AM, Timmins-Schiffman E. Variations in Copepod Proteome and Respiration Rate in Association with Diel Vertical Migration and Circadian Cycle. THE BIOLOGICAL BULLETIN 2018; 235:30-42. [PMID: 30160998 DOI: 10.1086/699219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The diel vertical migration of zooplankton is a process during which individuals spend the night in surface waters and retreat to depth during the daytime, with substantial implications for carbon transport and the ecology of midwater ecosystems. The physiological consequences of this daily pattern have, however, been poorly studied beyond investigations of speed and the energetic cost of swimming. Many other processes are likely influenced, such as fuel use, energetic trade-offs, underlying diel (circadian) rhythms, and antioxidant responses. Using a new reference transcriptome, proteomic analyses were applied to compare the physiological state of a migratory copepod, Pleuromamma xiphias, immediately after arriving to the surface at night and six hours later. Oxygen consumption was monitored semi-continuously to explore underlying cyclical patterns in metabolic rate under dark-dark conditions. The proteomic analysis suggests a distinct shift in physiology that reflects migratory exertion and changes in metabolism. These proteomic analyses are supported by the respiration experiments, which show an underlying cycle in metabolic rate, with a peak at dawn. This project generates molecular tools (transcriptome and proteome) that will allow for more detailed understanding of the underlying physiological processes that influence and are influenced by diel vertical migration. Further, these studies suggest that P. xiphias is a tractable model for continuing investigations of circadian and diel vertical migration influences on plankton physiology. Previous studies did not account for this cyclic pattern of respiration and may therefore have unrepresented respiratory carbon fluxes from copepods by about 24%.
Collapse
Key Words
- ACN, acetonitrile
- ANOSIM, analysis of similarity
- BATS, Bermuda Atlantic Time Series
- BUSCO, Benchmarking Universal Single-Copy Orthologs
- DM, dry mass
- DVM, diel vertical migration
- FFT-NLLS, fast Fourier transform non-linear least squares
- GO, gene ontology
- MESA, maximum entropy spectral analysis
- NAD+, oxidized nicotinamide adenine dinucleotide
- NAD, nicotinamide adenine dinucleotide
- NADH, reduced nicotinamide adenine dinucleotide
- NMDS, non-metric multidimensional scaling
- NSAF, normalized spectral abundance factor
- RT, room temperature
- TTP, Trans Proteomic Pipeline
- nr, non-redundant database
Collapse
|
15
|
Biscontin A, Wallach T, Sales G, Grudziecki A, Janke L, Sartori E, Bertolucci C, Mazzotta G, De Pittà C, Meyer B, Kramer A, Costa R. Functional characterization of the circadian clock in the Antarctic krill, Euphausia superba. Sci Rep 2017; 7:17742. [PMID: 29255161 PMCID: PMC5735174 DOI: 10.1038/s41598-017-18009-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/05/2017] [Indexed: 11/30/2022] Open
Abstract
Antarctic krill (Euphausia superba) is a key species in Southern Ocean ecosystem where it plays a central role in the Antarctic food web. Available information supports the existence of an endogenous timing system in krill enabling it to synchronize metabolism and behavior with an environment characterized by extreme seasonal changes in terms of day length, food availability, and surface ice extent. A screening of our transcriptome database “KrillDB” allowed us to identify the putative orthologues of 20 circadian clock components. Mapping of conserved domains and phylogenetic analyses strongly supported annotations of the identified sequences. Luciferase assays and co-immunoprecipitation experiments allowed us to define the role of the main clock components. Our findings provide an overall picture of the molecular mechanisms underlying the functioning of the endogenous circadian clock in the Antarctic krill and shed light on their evolution throughout crustaceans speciation. Interestingly, the core clock machinery shows both mammalian and insect features that presumably contribute to an evolutionary strategy to cope with polar environment’s challenges. Moreover, despite the extreme variability characterizing the Antarctic seasonal day length, the conserved light mediated degradation of the photoreceptor EsCRY1 suggests a persisting pivotal role of light as a Zeitgeber.
Collapse
Affiliation(s)
- Alberto Biscontin
- Charité-Universitätsmedizin Berlin, Laboratory of Chronobiology, D-10117, Berlin, Germany.,Department of Biology, University of Padova, 35121, Padova, Italy
| | - Thomas Wallach
- Charité-Universitätsmedizin Berlin, Laboratory of Chronobiology, D-10117, Berlin, Germany
| | - Gabriele Sales
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Astrid Grudziecki
- Charité-Universitätsmedizin Berlin, Laboratory of Chronobiology, D-10117, Berlin, Germany
| | - Leonard Janke
- Charité-Universitätsmedizin Berlin, Laboratory of Chronobiology, D-10117, Berlin, Germany
| | - Elena Sartori
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Cristiano Bertolucci
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121, Ferrara, Italy
| | | | | | - Bettina Meyer
- Alfred Wegener Polar Biological Oceanography, 27570, Bremerhaven, Germany.,Carl von Ossietzky University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, 26129, Oldenburg, Germany.,Helmholtz Institute for Functional Marine Biodiversity Oldenburg (HIFMB), 26129, Oldenburg, Germany
| | - Achim Kramer
- Charité-Universitätsmedizin Berlin, Laboratory of Chronobiology, D-10117, Berlin, Germany.
| | - Rodolfo Costa
- Department of Biology, University of Padova, 35121, Padova, Italy.
| |
Collapse
|
16
|
Christie AE, Yu A, Pascual MG. Circadian signaling in the Northern krill Meganyctiphanes norvegica: In silico prediction of the protein components of a putative clock system using a publicly accessible transcriptome. Mar Genomics 2017; 37:97-113. [PMID: 28964713 DOI: 10.1016/j.margen.2017.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/01/2017] [Accepted: 09/02/2017] [Indexed: 11/25/2022]
Abstract
The Northern krill Meganyctiphanes norvegica is a significant component of the zooplankton community in many regions of the North Atlantic Ocean. In the areas it inhabits, M. norvegica is of great importance ecologically, as it is both a major consumer of phytoplankton/small zooplankton and is a primary food source for higher-level consumers. One behavior of significance for both feeding and predator avoidance in Meganyctiphanes is diel vertical migration (DVM), i.e., a rising from depth at dusk and a return to depth at dawn. In this and other euphausiids, an endogenous circadian pacemaker is thought, at least in part, to control DVM. Currently, there is no information concerning the identity of the genes/proteins that comprise the M. norvegica circadian system. In fact, there is little information concerning the molecular underpinnings of circadian rhythmicity in crustaceans generally. Here, a publicly accessible transcriptome was used to identify the molecular components of a putative Meganyctiphanes circadian system. A complete set of core clock proteins was deduced from the M. norvegica transcriptome (clock, cryptochrome 2, cycle, period and timeless), as was a large suite of proteins that likely function as modulators of the core clock (e.g., doubletime), or serves as inputs to it (cryptochrome 1) or outputs from it (pigment dispersing hormone). This is the first description of a "complete" (core clock through putative output pathway signals) euphausiid clock system, and as such, provides a foundation for initiating molecular investigations of circadian signaling in M. norvegica and other krill species, including how clock systems may regulate DVM and other behaviors.
Collapse
Affiliation(s)
- Andrew E Christie
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI 96822, USA.
| | - Andy Yu
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI 96822, USA
| | - Micah G Pascual
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI 96822, USA
| |
Collapse
|
17
|
Hunt BJ, Özkaya Ö, Davies NJ, Gaten E, Seear P, Kyriacou CP, Tarling G, Rosato E. The Euphausia superba transcriptome database, SuperbaSE: An online, open resource for researchers. Ecol Evol 2017; 7:6060-6077. [PMID: 30094004 PMCID: PMC6077532 DOI: 10.1002/ece3.3168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/28/2017] [Accepted: 05/21/2017] [Indexed: 11/13/2022] Open
Abstract
Antarctic krill (Euphausia superba) is a crucial component of the Southern Ocean ecosystem, acting as the major link between primary production and higher trophic levels with an annual predator demand of up to 470 million tonnes. It also acts as an ecosystem engineer, affecting carbon sequestration and recycling iron and nitrogen, and has increasing importance as a commercial product in the aquaculture and health industries. Here we describe the creation of a de novo assembled head transcriptome for E. superba. As an example of its potential as a molecular resource, we relate its exploitation in identifying and characterizing numerous genes related to the circadian clock in E. superba, including the major components of the central feedback loop. We have made the transcriptome openly accessible for a wider audience of ecologists, molecular biologists, evolutionary geneticists, and others in a user-friendly format at SuperbaSE, hosted at http://www.krill.le.ac.uk.
Collapse
Affiliation(s)
- Benjamin J. Hunt
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| | - Özge Özkaya
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| | - Nathaniel J. Davies
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| | - Edward Gaten
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| | - Paul Seear
- British Antarctic SurveyNatural Environment Research CouncilCambridgeUK
| | - Charalambos P. Kyriacou
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| | - Geraint Tarling
- British Antarctic SurveyNatural Environment Research CouncilCambridgeUK
| | - Ezio Rosato
- Department of GeneticsCollege of MedicineBiological Sciences and Psychology University of LeicesterUniversity RoadLeicesterUK
| |
Collapse
|
18
|
Häfker NS, Meyer B, Last KS, Pond DW, Hüppe L, Teschke M. Circadian Clock Involvement in Zooplankton Diel Vertical Migration. Curr Biol 2017; 27:2194-2201.e3. [DOI: 10.1016/j.cub.2017.06.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/08/2017] [Accepted: 06/09/2017] [Indexed: 12/21/2022]
|
19
|
Payton L, Perrigault M, Hoede C, Massabuau JC, Sow M, Huvet A, Boullot F, Fabioux C, Hegaret H, Tran D. Remodeling of the cycling transcriptome of the oyster Crassostrea gigas by the harmful algae Alexandrium minutum. Sci Rep 2017; 7:3480. [PMID: 28615697 PMCID: PMC5471176 DOI: 10.1038/s41598-017-03797-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/04/2017] [Indexed: 11/24/2022] Open
Abstract
As a marine organism, the oyster Crassostrea gigas inhabits a complex biotope governed by interactions between the moon and the sun cycles. We used next-generation sequencing to investigate temporal regulation of oysters under light/dark entrainment and the impact of harmful algal exposure. We found that ≈6% of the gills' transcriptome exhibits circadian expression, characterized by a nocturnal and bimodal pattern. Surprisingly, a higher number of ultradian transcripts were also detected under solely circadian entrainment. The results showed that a bloom of Alexandrium minutum generated a remodeling of the bivalve's temporal structure, characterized by a loss of oscillations, a genesis of de novo oscillating transcripts, and a switch in the period of oscillations. These findings provide unprecedented insights into the diurnal landscape of the oyster's transcriptome and pleiotropic remodeling due to toxic algae exposure, revealing the intrinsic plasticity of the cycling transcriptome in oysters.
Collapse
Affiliation(s)
- Laura Payton
- University of Bordeaux, EPOC, UMR 5805, F-33120, Arcachon, France
- CNRS, EPOC, UMR 5805, F-33120, Arcachon, France
| | - Mickael Perrigault
- University of Bordeaux, EPOC, UMR 5805, F-33120, Arcachon, France
- CNRS, EPOC, UMR 5805, F-33120, Arcachon, France
| | - Claire Hoede
- Plate-forme bio-informatique Genotoul, MIAT, Université de Toulouse, INRA, F-31326, Castanet-Tolosan, France
| | - Jean-Charles Massabuau
- University of Bordeaux, EPOC, UMR 5805, F-33120, Arcachon, France
- CNRS, EPOC, UMR 5805, F-33120, Arcachon, France
| | - Mohamedou Sow
- University of Bordeaux, EPOC, UMR 5805, F-33120, Arcachon, France
| | - Arnaud Huvet
- Ifremer, Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), CS 10070, F-29280, Plouzané, France
| | - Floriane Boullot
- Ifremer, Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), CS 10070, F-29280, Plouzané, France
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/IFREMER, F-29280, Plouzané, France
| | - Caroline Fabioux
- Ifremer, Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), CS 10070, F-29280, Plouzané, France
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/IFREMER, F-29280, Plouzané, France
| | - Hélène Hegaret
- Ifremer, Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), CS 10070, F-29280, Plouzané, France
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/IFREMER, F-29280, Plouzané, France
| | - Damien Tran
- University of Bordeaux, EPOC, UMR 5805, F-33120, Arcachon, France.
- CNRS, EPOC, UMR 5805, F-33120, Arcachon, France.
| |
Collapse
|
20
|
Bernatowicz PP, Kotwica-Rolinska J, Joachimiak E, Sikora A, Polanska MA, Pijanowska J, Bębas P. Temporal Expression of the Clock Genes in the Water FleaDaphnia pulex(Crustacea: Cladocera). ACTA ACUST UNITED AC 2016; 325:233-54. [DOI: 10.1002/jez.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 04/14/2016] [Accepted: 04/18/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Piotr P. Bernatowicz
- Department of Paleobiology and Evolution, Institute of Zoology, Faculty of Biology; University of Warsaw; Biological and Chemical Research Centre; Warsaw Poland
| | - Joanna Kotwica-Rolinska
- Department of Animal Physiology, Institute of Zoology, Faculty of Biology; University of Warsaw; Warsaw Poland
| | - Ewa Joachimiak
- Department of Cell Biology; Nencki Institute of Experimental Biology PAS; Warsaw Poland
| | - Anna Sikora
- Department of Hydrobiology, Institute of Zoology, Faculty of Biology; University of Warsaw; Biological and Chemical Research Centre; Warsaw Poland
| | - Marta A. Polanska
- Department of Animal Physiology, Institute of Zoology, Faculty of Biology; University of Warsaw; Warsaw Poland
| | - Joanna Pijanowska
- Department of Hydrobiology, Institute of Zoology, Faculty of Biology; University of Warsaw; Biological and Chemical Research Centre; Warsaw Poland
| | - Piotr Bębas
- Department of Animal Physiology, Institute of Zoology, Faculty of Biology; University of Warsaw; Warsaw Poland
| |
Collapse
|
21
|
The opsin repertoire of the Antarctic krill Euphausia superba. Mar Genomics 2016; 29:61-68. [PMID: 27157882 DOI: 10.1016/j.margen.2016.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/14/2016] [Accepted: 04/19/2016] [Indexed: 12/16/2022]
Abstract
The Antarctic krill Euphausia superba experiences almost all marine photic environments throughout its life cycle. Antarctic krill eggs hatch in the aphotic zone up to 1000m depth and larvae develop on their way to the ocean surface (development ascent) and are exposed to different quality (wavelength) and quantity (irradiance) of light. Adults show a daily vertical migration pattern, moving downward during the day and upward during the night within the top 200m of the water column. Seawater acts as a potent chromatic filter and animals have evolved different opsin photopigments to perceive photons of specific wavelengths. We have investigated the transcriptome of E. superba and, using a candidate gene approach, we identified six novel opsins. Five are r-type visual opsins: four middle-wavelength-sensitive (EsRh2, EsRh3, EsRh4 and EsRh5) and one long-wavelength-sensitive (EsRh6). Moreover, we have identified a non-visual opsin, the EsPeropsin. All these newly identified opsin genes were significantly expressed in compound eyes and brain, while only EsPeropsin and EsRh2 were clearly detected also in the abdomen. A temporal modulation in the transcription of these novel opsins was found, but statistically significant oscillations were only observed in EsRrh3 and EsPeropsin. Our results contribute to the dissection of the complex photoreception system of E. superba, which enables this species to respond to the daily and seasonal changes in irradiance and spectral composition in the Southern Ocean.
Collapse
|
22
|
|
23
|
Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter. Curr Biol 2016; 26:244-251. [DOI: 10.1016/j.cub.2015.11.038] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/16/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022]
|
24
|
|
25
|
Bamber SD, Westerlund S. Behavioral responses of brown shrimp (Crangon crangon) to reduced seawater pH following simulated leakages from sub-sea geological storage of CO2. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 79:526-537. [PMID: 27484135 DOI: 10.1080/15287394.2016.1171979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Large-scale storage of CO2 within sub-sea geological formations is a viable option for reducing the volume of this greenhouse gas released directly to the atmosphere from anthropogenic activities. Risks to benthic marine life following possible leakage of gas through the seabed from this carbon capture and storage (CCS) initiative are not yet well established. This study examined behavior (activity patterns) in brown shrimp (Crangon crangon), exposed to a range of reduced seawater pH conditions (7.6, 7, or 6.5) simulating leakage scenarios of varying scales. Brown shrimp have an endogenous rhythmicity associated with their activity, which dictates they are most active during hours of darkness, presumably as protection against vision-dependent predators. This endogenous rhythm in activity continues to be expressed when shrimp are held under constant low-light conditions in the lab and provides an ecologically relevant endpoint to measure when examining the influence of reduced pH on the behavior of these animals. No marked differences in activity pattern were observed between control shrimp maintained at pH 8.1 and those at pH 7.6. However, changes in activity were evident at pH 7 and pH 6.5, where significant shifts in timing and intensity of activity occurred. There was an unexpected increase in activity within periods of expected light, probably signaling efforts by shrimp to migrate away from reduced seawater pH conditions. The loss of this important member of the benthic community due to migration may have important consequences for many of the resilient species that remain.
Collapse
Affiliation(s)
- Shaw D Bamber
- a International Research Institute of Stavanger , Environment Department , Mekjarvik , Randaberg , Norway
| | - Stig Westerlund
- a International Research Institute of Stavanger , Environment Department , Mekjarvik , Randaberg , Norway
| |
Collapse
|
26
|
Meyer B, Teschke M. Physiology of Euphausia superba. BIOLOGY AND ECOLOGY OF ANTARCTIC KRILL 2016. [DOI: 10.1007/978-3-319-29279-3_4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
27
|
Identification, Characterization, and Diel Pattern of Expression of Canonical Clock Genes in Nephrops norvegicus (Crustacea: Decapoda) Eyestalk. PLoS One 2015; 10:e0141893. [PMID: 26524198 PMCID: PMC4629887 DOI: 10.1371/journal.pone.0141893] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 10/14/2015] [Indexed: 12/17/2022] Open
Abstract
The Norway lobster, Nephrops norvegicus, is a burrowing decapod with a rhythmic burrow emergence (24 h) governed by the circadian system. It is an important resource for European fisheries and its behavior deeply affects its availability. The current knowledge of Nephrops circadian biology is phenomenological as it is currently the case for almost all crustaceans. In attempt to elucidate the putative molecular mechanisms underlying circadian gene regulation in Nephrops, we used a transcriptomics approach on cDNA extracted from the eyestalk, a structure playing a crucial role in controlling behavior of decapods. We studied 14 male lobsters under 12–12 light-darkness blue light cycle. We used the Hiseq 2000 Illumina platform to sequence two eyestalk libraries (under light and darkness conditions) obtaining about 90 millions 100-bp paired-end reads. Trinity was used for the de novo reconstruction of transcriptomes; the size at which half of all assembled bases reside in contigs (N50) was equal to 1796 (light) and 2055 (darkness). We found a list of candidate clock genes and focused our attention on canonical ones: timeless, period, clock and bmal1. The cloning of assembled fragments validated Trinity outputs. The putative Nephrops clock genes showed high levels of identity (blastx on NCBI) with known crustacean clock gene homologs such as Eurydice pulchra (period: 47%, timeless: 59%, bmal1: 79%) and Macrobrachium rosenbergii (clock: 100%). We also found a vertebrate-like cryptochrome 2. RT-qPCR showed that only timeless had a robust diel pattern of expression. Our data are in accordance with the current knowledge of the crustacean circadian clock, reinforcing the idea that the molecular clockwork of this group shows some differences with the established model in Drosophila melanogaster.
Collapse
|
28
|
Kobelkova A, Goto SG, Peyton JT, Ikeno T, Lee RE, Denlinger DL. Continuous activity and no cycling of clock genes in the Antarctic midge during the polar summer. JOURNAL OF INSECT PHYSIOLOGY 2015; 81:90-96. [PMID: 26172960 DOI: 10.1016/j.jinsphys.2015.07.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
The extreme seasonal shifts of day length in polar regions, ranging from constant light in the summer to constant darkness in the winter, pose an intriguing environment for probing activity rhythms and the functioning of circadian clocks. Here, we monitor locomotor activity during the summer on the Antarctic Peninsula and under laboratory conditions, as well as the accompanying patterns of clock gene expression in the Antarctic midge, the only insect endemic to Antarctica. Larvae and adults are most active during the warmest portion of the day, but at a constant temperature they remain continuously active regardless of the photoregime, and activity also persists in constant darkness. The canonical clock genes period, timeless, Clock, and vrille are expressed in the head but we detected no cycling of expression in either the field or under diverse photoregimes in the laboratory. The timekeeping function of the clock has possibly been lost, enabling the midge to opportunistically exploit the unpredictable availability of permissive thermal conditions for growth, development, and reproduction during the short summer in Antarctica.
Collapse
Affiliation(s)
- Alena Kobelkova
- Departments of Entomology and Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210, USA
| | - Shin G Goto
- Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Justin T Peyton
- Departments of Entomology and Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210, USA
| | - Tomoko Ikeno
- Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Richard E Lee
- Department of Zoology, Miami University, Oxford, OH 45056, USA
| | - David L Denlinger
- Departments of Entomology and Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210, USA.
| |
Collapse
|
29
|
Meyer B, Martini P, Biscontin A, De Pittà C, Romualdi C, Teschke M, Frickenhaus S, Harms L, Freier U, Jarman S, Kawaguchi S. Pyrosequencing and de novo assembly of Antarctic krill (Euphausia superba) transcriptome to study the adaptability of krill to climate-induced environmental changes. Mol Ecol Resour 2015; 15:1460-71. [PMID: 25818178 PMCID: PMC4672718 DOI: 10.1111/1755-0998.12408] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 03/13/2015] [Accepted: 03/18/2015] [Indexed: 11/28/2022]
Abstract
The Antarctic krill, Euphausia superba, has a key position in the Southern Ocean food web by serving as direct link between primary producers and apex predators. The south-west Atlantic sector of the Southern Ocean, where the majority of the krill population is located, is experiencing one of the most profound environmental changes worldwide. Up to now, we have only cursory information about krill’s genomic plasticity to cope with the ongoing environmental changes induced by anthropogenic CO2 emission. The genome of krill is not yet available due to its large size (about 48 Gbp). Here, we present two cDNA normalized libraries from whole krill and krill heads sampled in different seasons that were combined with two data sets of krill transcriptome projects, already published, to produce the first knowledgebase krill ‘master’ transcriptome. The new library produced 25% more E. superba transcripts and now includes nearly all the enzymes involved in the primary oxidative metabolism (Glycolysis, Krebs cycle and oxidative phosphorylation) as well as all genes involved in glycogenesis, glycogen breakdown, gluconeogenesis, fatty acid synthesis and fatty acids β-oxidation. With these features, the ‘master’ transcriptome provides the most complete picture of metabolic pathways in Antarctic krill and will provide a major resource for future physiological and molecular studies. This will be particularly valuable for characterizing the molecular networks that respond to stressors caused by the anthropogenic CO2 emissions and krill’s capacity to cope with the ongoing environmental changes in the Atlantic sector of the Southern Ocean.
Collapse
Affiliation(s)
- B 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, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111, Oldenburg, Germany
| | - P Martini
- Dipartimento di Biologia, Università degli Studi di Padova, via U. Bassi, 58/B, 35131, Padova, Italy
| | - A Biscontin
- Dipartimento di Biologia, Università degli Studi di Padova, via U. Bassi, 58/B, 35131, Padova, Italy
| | - C De Pittà
- Dipartimento di Biologia, Università degli Studi di Padova, via U. Bassi, 58/B, 35131, Padova, Italy
| | - C Romualdi
- Dipartimento di Biologia, Università degli Studi di Padova, via U. Bassi, 58/B, 35131, Padova, Italy
| | - M Teschke
- Section Polar Biological Oceanography, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - S Frickenhaus
- Section Scientific Computing, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.,Hochschule Bremerhaven, An der Karlstadt 8, 27568, Bremerhaven, Germany
| | - L Harms
- Section Scientific Computing, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - U Freier
- SC-Scientific Consulting, Münchener Str. 41a, D-41472, Neuss, Germany
| | - S Jarman
- Australian Antarctic Division, Kingston, Tas., 7050, Australia
| | - S Kawaguchi
- Australian Antarctic Division, Kingston, Tas., 7050, Australia
| |
Collapse
|
30
|
Auerswald L, Meyer B, Teschke M, Hagen W, Kawaguchi S. Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation. Polar Biol 2015. [DOI: 10.1007/s00300-014-1638-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
31
|
Euphausiid respiration model revamped: Latitudinal and seasonal shaping effects on krill respiration rates. Ecol Modell 2014. [DOI: 10.1016/j.ecolmodel.2014.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
32
|
Oliveri P, Fortunato AE, Petrone L, Ishikawa-Fujiwara T, Kobayashi Y, Todo T, Antonova O, Arboleda E, Zantke J, Tessmar-Raible K, Falciatore A. The Cryptochrome/Photolyase Family in aquatic organisms. Mar Genomics 2014; 14:23-37. [DOI: 10.1016/j.margen.2014.02.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/05/2014] [Accepted: 02/10/2014] [Indexed: 01/12/2023]
|
33
|
Toullec JY, Corre E, Bernay B, Thorne MAS, Cascella K, Ollivaux C, Henry J, Clark MS. Transcriptome and peptidome characterisation of the main neuropeptides and peptidic hormones of a euphausiid: the Ice Krill, Euphausia crystallorophias. PLoS One 2013; 8:e71609. [PMID: 23990964 PMCID: PMC3749230 DOI: 10.1371/journal.pone.0071609] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 07/01/2013] [Indexed: 11/19/2022] Open
Abstract
Background The Ice krill, Euphausia crystallorophias is one of the species at the base of the Southern Ocean food chain. Given their significant contribution to the biomass of the Southern Ocean, it is vitally important to gain a better understanding of their physiology and, in particular, anticipate their responses to climate change effects in the warming seas around Antarctica. Methodology/Principal Findings Illumina sequencing was used to produce a transcriptome of the ice krill. Analysis of the assembled contigs via two different methods, produced 36 new pre-pro-peptides, coding for 61 neuropeptides or peptide hormones belonging to the following families: Allatostatins (A, B et C), Bursicon (α and β), Crustacean Hyperglycemic Hormones (CHH and MIH/VIHs), Crustacean Cardioactive Peptide (CCAP), Corazonin, Diuretic Hormones (DH), the Eclosion Hormone (EH), Neuroparsin, Neuropeptide F (NPF), small Neuropeptide F (sNPF), Pigment Dispersing Hormone (PDH), Red Pigment Concentrating Hormone (RPCH) and finally Tachykinin. LC/MS/MS proteomics was also carried out on eyestalk extracts, which are the major site of neuropeptide synthesis in decapod crustaceans. Results confirmed the presence of six neuropeptides and six precursor-related peptides previously identified in the transcriptome analyses. Conclusions This study represents the first comprehensive analysis of neuropeptide hormones in a Eucarida non-decapod Malacostraca, several of which are described for the first time in a non-decapod crustacean. Additionally, there is a potential expansion of PDH and Neuropeptide F family members, which may reflect certain life history traits such as circadian rhythms associated with diurnal migrations and also the confirmation via mass spectrometry of several novel pre-pro-peptides, of unknown function. Knowledge of these essential hormones provides a vital framework for understanding the physiological response of this key Southern Ocean species to climate change and provides a valuable resource for studies into the molecular phylogeny of these organisms and the evolution of neuropeptide hormones.
Collapse
Affiliation(s)
- Jean-Yves Toullec
- UPMC University of Paris 06, UMR 7144 CNRS, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- * E-mail:
| | - Erwan Corre
- UPMC University of Paris 06, FR 2424 CNRS, ABiMS, Analysis and Bioinformatics for Marine Science, Station Biologique de Roscoff, Roscoff, France
| | - Benoît Bernay
- University of Caen Basse Normandie, FRE 3484 CNRS, Biologie des Mollusques Marins et des Ecosystèmes Associés, Caen, France
- University of Caen Basse Normandie, Plateforme PROTEOGEN, Caen, France, SF ICORE 4206
| | - Michael A. S. Thorne
- British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, United Kingdom
| | - Kévin Cascella
- UPMC University of Paris 06, UMR 7144 CNRS, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7144, Station Biologique de Roscoff, Roscoff, France
| | - Céline Ollivaux
- UPMC University of Paris 06, UMR 7150 CNRS, Mer et Santé, Station Biologique de Roscoff, Roscoff, France
- Centre National de la Recherche Scientifique, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, UEB, France
| | - Joël Henry
- University of Caen Basse Normandie, FRE 3484 CNRS, Biologie des Mollusques Marins et des Ecosystèmes Associés, Caen, France
- University of Caen Basse Normandie, Plateforme PROTEOGEN, Caen, France, SF ICORE 4206
| | - Melody S. Clark
- British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, United Kingdom
| |
Collapse
|
34
|
The Antarctic krill Euphausia superba shows diurnal cycles of transcription under natural conditions. PLoS One 2013; 8:e68652. [PMID: 23874706 PMCID: PMC3714250 DOI: 10.1371/journal.pone.0068652] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 05/30/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Polar environments are characterized by extreme seasonal changes in day length, light intensity and spectrum, the extent of sea ice during the winter, and food availability. A key species of the Southern Ocean ecosystem, the Antarctic krill (Euphausia superba) has evolved rhythmic physiological and behavioral mechanisms to adapt to daily and seasonal changes. The molecular organization of the clockwork underlying these biological rhythms is, nevertheless, still only partially understood. METHODOLOGY/PRINCIPAL FINDINGS The genome sequence of the Antarctic krill is not yet available. A normalized cDNA library was produced and pyrosequenced in the attempt to identify large numbers of transcripts. All available E. superba sequences were then assembled to create the most complete existing oligonucleotide microarray platform with a total of 32,217 probes. Gene expression signatures of specimens collected in the Ross Sea at five different time points over a 24-hour cycle were defined, and 1,308 genes differentially expressed were identified. Of the corresponding transcripts, 609 showed a significant sinusoidal expression pattern; about 40% of these exibithed a 24-hour periodicity while the other 60% was characterized by a shorter (about 12-hour) rhythm. We assigned the differentially expressed genes to functional categories and noticed that those concerning translation, proteolysis, energy and metabolic process, redox regulation, visual transduction and stress response, which are most likely related to daily environmental changes, were significantly enriched. Two transcripts of peroxiredoxin, thought to represent the ancestral timekeeping system that evolved about 2.5 billion years ago, were also identified as were two isoforms of the EsRh1 opsin and two novel arrestin1 sequences involved in the visual transduction cascade. CONCLUSIONS Our work represents the first characterization of the krill diurnal transcriptome under natural conditions and provides a first insight into the genetic regulation of physiological changes, which occur around the clock during an Antarctic summer day.
Collapse
|
35
|
Brown M, Kawaguchi S, Candy S, Yoshida T, Virtue P, Nicol S. Long-Term Effect of Photoperiod, Temperature and Feeding Regimes on the Respiration Rates of Antarctic Krill (<i>Euphausia superba</i>). ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojms.2013.32a005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
36
|
The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective. Polar Biol 2011. [DOI: 10.1007/s00300-011-1120-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|