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Laetz EMJ, Kahyaoglu C, Borgstein NM, Merkx M, van der Meij SET, Verberk WCEP. Critical thermal maxima and oxygen uptake in Elysia viridis, a sea slug that steals chloroplasts to photosynthesize. J Exp Biol 2024; 227:jeb246331. [PMID: 38629207 DOI: 10.1242/jeb.246331] [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: 06/19/2023] [Accepted: 03/31/2024] [Indexed: 05/31/2024]
Abstract
Photosynthetic animals produce oxygen, providing an ideal lens for studying how oxygen dynamics influence thermal sensitivity. The algivorous sea slug Elysia viridis can steal and retain chloroplasts from the marine alga Bryopsis sp. for months when starved, but chloroplast retention is mere weeks when they are fed another green alga, Chaetomorpha sp. To examine plasticity in thermal tolerance and changes in net oxygen exchange when fed and starving, slugs fed each alga were acclimated to 17°C (the current maximum temperature to which they are exposed in nature) and 22°C (the increase predicted for 2100) and measured at different points during starvation. We also examined increased illumination to evaluate a potential tradeoff between increased oxygen production but faster chloroplast degradation. Following acclimation, we subjected slugs to acute thermal stress to determine their thermal tolerance. We also measured net oxygen exchange before and after acute thermal stress. Thermal tolerance improved in slugs acclimated to 22°C, indicating they can acclimate to temperatures higher than they naturally experience. All slugs exhibited net oxygen uptake, and rates were highest in recently fed slugs before exposure to acute thermal stress. Oxygen uptake was suppressed following acute thermal stress. Under brighter light, slugs exhibited improved thermal tolerance, possibly because photosynthetic oxygen production alleviated oxygen limitation. Accordingly, this advantage disappeared later in starvation when photosynthesis ceased. Thus, E. viridis can cope with heatwaves by suppressing metabolism and plastically adjusting heat tolerance; however, starvation influences a slug's thermal tolerance and oxygen uptake such that continuous access to algal food for its potential nutritive and oxygenic benefits is critical when facing thermal stress.
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Affiliation(s)
- Elise M J Laetz
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Can Kahyaoglu
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Natascha M Borgstein
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Michiel Merkx
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Sancia E T van der Meij
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands
| | - Wilco C E P Verberk
- Department of Ecology, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Christa G. Kleptoplasty. Curr Biol 2023; 33:R465-R467. [PMID: 37279674 DOI: 10.1016/j.cub.2023.03.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Gregor Christa introduces kleptoplasty - the process by which heterotrophs steal chloroplasts from algae and incorporate them into their cytosol.
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Affiliation(s)
- Gregor Christa
- Institute for Zoology, University of Wuppertal, Wuppertal, Germany.
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3
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Light modulates the lipidome of the photosynthetic sea slug Elysia timida. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159249. [PMID: 36336252 DOI: 10.1016/j.bbalip.2022.159249] [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: 06/14/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Long-term kleptoplasty, the capability to retain functional stolen chloroplasts (kleptoplasts) for several weeks to months, has been shown in a handful of Sacoglossa sea slugs. One of these sea slugs is Elysia timida, endemic to the Mediterranean, which retains functional chloroplasts of the macroalga Acetabularia acetabulum. To understand how light modulates the lipidome of E. timida, sea slug specimens were subjected to two different 4-week light treatments: regular light and quasi-dark conditions. Lipidomic analyses were performed by HILIC-HR-ESI-MS and MS/MS. Quasi-dark conditions caused a reduction in the amount of essential lipids for photosynthetic membranes, such as glycolipids, indicating high level of kleptoplast degradation under sub-optimal light conditions. However, maximum photosynthetic capacities (Fv/Fm) were identical in both light treatments (≈0.75), showing similar kleptoplast functionality and suggesting that older kleptoplasts were targeted for degradation. Although more stable, the phospholipidome showed differences between light treatments: the amount of certain lipid species of phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylglycerol (PG) decreased under quasi-dark conditions, while other lipid species of phosphatidylcholine (PC), PE and lyso-PE (LPE) increased. Quasi-dark conditions promoted a decrease in the relative abundance of polyunsaturated fatty acids. These results suggest a light-driven remodelling of the lipidome according to the functions of the different lipids and highlight the plasticity of polar lipids in the photosynthetic sea slug E. timida.
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Abstract
Kleptoplasty, the process by which a host organism sequesters and retains algal chloroplasts, is relatively common in protists. The origin of the plastid varies, as do the length of time it is retained in the host and the functionality of the association. In metazoa, the capacity for long-term (several weeks to months) maintenance of photosynthetically active chloroplasts is a unique characteristic of a handful of sacoglossan sea slugs. This capability has earned these slugs the epithets "crawling leaves" and "solar-powered sea slugs." This Unsolved Mystery explores the basis of chloroplast maintenance and function and attempts to clarify contradictory results in the published literature. We address some of the mysteries of this remarkable association. Why are functional chloroplasts retained? And how is the function of stolen chloroplasts maintained without the support of the algal nucleus?
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Cartaxana P, Rey F, LeKieffre C, Lopes D, Hubas C, Spangenberg JE, Escrig S, Jesus B, Calado G, Domingues R, Kühl M, Calado R, Meibom A, Cruz S. Photosynthesis from stolen chloroplasts can support sea slug reproductive fitness. Proc Biol Sci 2021; 288:20211779. [PMID: 34583582 PMCID: PMC8479339 DOI: 10.1098/rspb.2021.1779] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/07/2021] [Indexed: 12/13/2022] Open
Abstract
Some sea slugs are able to steal functional chloroplasts (kleptoplasts) from their algal food sources, but the role and relevance of photosynthesis to the animal host remain controversial. While some researchers claim that kleptoplasts are slowly digestible 'snacks', others advocate that they enhance the overall fitness of sea slugs much more profoundly. Our analysis shows light-dependent incorporation of 13C and 15N in the albumen gland and gonadal follicles of the sea slug Elysia timida, representing translocation of photosynthates to kleptoplast-free reproductive organs. Long-chain polyunsaturated fatty acids with reported roles in reproduction were produced in the sea slug cells using labelled precursors translocated from the kleptoplasts. Finally, we report reduced fecundity of E. timida by limiting kleptoplast photosynthesis. The present study indicates that photosynthesis enhances the reproductive fitness of kleptoplast-bearing sea slugs, confirming the biological relevance of this remarkable association between a metazoan and an algal-derived organelle.
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Affiliation(s)
- Paulo Cartaxana
- CESAM—Centre for Environmental and Marine Studies, University of Aveiro, Aveiro 3810-193, Portugal
- Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Felisa Rey
- CESAM—Centre for Environmental and Marine Studies, University of Aveiro, Aveiro 3810-193, Portugal
- Mass Spectrometry Centre, LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro 3810-193, Portugal
| | - Charlotte LeKieffre
- Cell and Plant Physiology Laboratory, University of Grenoble Alpes, CNRS, CEA, INRAE, Grenoble Cedex, France
| | - Diana Lopes
- CESAM—Centre for Environmental and Marine Studies, University of Aveiro, Aveiro 3810-193, Portugal
| | - Cédric Hubas
- Biologie des Organismes et Écosystèmes Aquatiques (UMR BOREA 8067), Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, Station Marine de Concarneau, Place de la croix, Concarneau 29900, France
| | - Jorge E. Spangenberg
- Institute of Earth Surface Dynamics (IDYST), University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - Bruno Jesus
- Laboratoire Mer Molécules Santé, Faculté des Sciences et des Techniques, Université de Nantes, Nantes 44322, France
| | - Gonçalo Calado
- Department of Life Sciences, Lusófona University, Campo Grande 376, Lisbon 1749-024, Portugal
- NOVA School of Science and Technology, MARE—Marine and Environmental Sciences Centre, Campus de Caparica, Caparica 2829-516, Portugal
| | - Rosário Domingues
- Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
- Mass Spectrometry Centre, LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro 3810-193, Portugal
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør 3000, Denmark
| | - Ricardo Calado
- CESAM—Centre for Environmental and Marine Studies, University of Aveiro, Aveiro 3810-193, Portugal
| | - Anders Meibom
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Sónia Cruz
- CESAM—Centre for Environmental and Marine Studies, University of Aveiro, Aveiro 3810-193, Portugal
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Shiroyama H, Mitoh S, Ida TY, Yusa Y. Adaptive significance of light and food for a kleptoplastic sea slug: implications for photosynthesis. Oecologia 2020; 194:455-463. [DOI: 10.1007/s00442-020-04779-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 10/08/2020] [Indexed: 01/23/2023]
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Rey F, Melo T, Cartaxana P, Calado R, Domingues P, Cruz S, Domingues MRM. Coping with Starvation: Contrasting Lipidomic Dynamics in the Cells of Two Sacoglossan Sea Slugs Incorporating Stolen Plastids from the Same Macroalga. Integr Comp Biol 2020; 60:43-56. [PMID: 32294176 DOI: 10.1093/icb/icaa019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Several species of sacoglossan sea slugs are able to sequester chloroplasts from algae and incorporate them into their cells. However, the ability to maintain functional "stolen" plastids (kleptoplasts) can vary significantly within the Sacoglossa, giving species different capacities to withstand periods of food shortage. The present study provides an insight on the comparative shifts experienced by the lipidome of two sacoglossan sea slug species, Elysia viridis (long-term retention of functional chloroplasts) and Placida dendritica (retention of non-functional chloroplasts). A hydrophilic interaction liquid chromatography-mass spectrometry approach was employed to screen the lipidome of specimens from both species feeding on the macroalga Codium tomentosum and after 1-week of starvation. The lipidome of E. viridis was generally unaffected by the absence of food, while that of P. dendritica varied significantly. The retention of functional chloroplasts by E. viridis cells allows this species to endure periods of food shortage, while in P. dendritica a significant reduction in the amount of main lipids was the consequence of the consumption of its own mass to endure starvation. The large proportion of ether phospholipids (plasmalogens) in both sea slug species suggests that these compounds may play a key role in chloroplast incorporation in sea slug cells and/or be involved in the reduction of the oxidative stress resulting from the presence of kleptoplasts.
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Affiliation(s)
- Felisa Rey
- CESAM, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal.,Mass Spectrometry Centre & QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - Tânia Melo
- CESAM, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal.,Mass Spectrometry Centre & QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - Paulo Cartaxana
- ECOMARE, CESAM, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - Ricardo Calado
- ECOMARE, CESAM, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - Pedro Domingues
- Mass Spectrometry Centre & QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - Sónia Cruz
- ECOMARE, CESAM, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
| | - M Rosário M Domingues
- CESAM, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal.,Mass Spectrometry Centre & QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal
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Cruz S, LeKieffre C, Cartaxana P, Hubas C, Thiney N, Jakobsen S, Escrig S, Jesus B, Kühl M, Calado R, Meibom A. Functional kleptoplasts intermediate incorporation of carbon and nitrogen in cells of the Sacoglossa sea slug Elysia viridis. Sci Rep 2020; 10:10548. [PMID: 32601288 PMCID: PMC7324368 DOI: 10.1038/s41598-020-66909-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/26/2020] [Indexed: 01/16/2023] Open
Abstract
Some sacoglossan sea slugs incorporate intracellular functional algal chloroplasts, a process termed kleptoplasty. “Stolen” chloroplasts (kleptoplasts) can remain photosynthetically active up to several months, contributing to animal nutrition. Whether this contribution occurs by means of translocation of photosynthesis-derived metabolites from functional kleptoplasts to the animal host or by simple digestion of such organelles remains controversial. Imaging of 13C and 15N assimilation over a 12-h incubation period of Elysia viridis sea slugs showed a light-dependent incorporation of carbon and nitrogen, observed first in digestive tubules and followed by a rapid accumulation into chloroplast-free organs. Furthermore, this work revealed the presence of 13C-labeled long-chain fatty acids (FA) typical of marine invertebrates, such as arachidonic (20:4n-6) and adrenic (22:4n-6) acids. The time frame and level of 13C- and 15N-labeling in chloroplast-free organs indicate that photosynthesis-derived primary metabolites were made available to the host through functional kleptoplasts. The presence of specific 13C-labeled long-chain FA, absent from E. viridis algal food, indicates animal based-elongation using kleptoplast-derived FA precursors. Finally, carbon and nitrogen were incorporated in organs and tissues involved in reproductive functions (albumin gland and gonadal follicles), implying a putative role of kleptoplast photosynthesis in the reproductive fitness of the animal host.
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Affiliation(s)
- Sónia Cruz
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Charlotte LeKieffre
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.,UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers, Cedex 1, France.,Cell & Plant Physiology Laboratory, University of Grenoble Alpes, CNRS, CEA, INRA, Grenoble, France
| | - Paulo Cartaxana
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Cédric Hubas
- Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, Station Marine de Concarneau, Place de la croix, 29900, Concarneau, France
| | - Najet Thiney
- Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, Station Marine de Concarneau, Place de la croix, 29900, Concarneau, France
| | - Sofie Jakobsen
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000, Helsingør, Denmark
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Bruno Jesus
- Laboratoire Mer Molécules Santé, Faculté des Sciences et des Techniques, Université de Nantes, 44322, Nantes, France
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000, Helsingør, Denmark
| | - Ricardo Calado
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Anders Meibom
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, 1015, Lausanne, Switzerland
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Donohoo SA, Wade RM, Sherwood AR. Finding the Sweet Spot: Sub-Ambient Light Increases Fitness and Kleptoplast Survival in the Sea Slug Plakobranchus cf. ianthobaptus Gould, 1852. THE BIOLOGICAL BULLETIN 2020; 238:154-166. [PMID: 32597715 DOI: 10.1086/709371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sacoglossans, or "sap-sucking" sea slugs, are primarily algivorous, with many taxa exhibiting kleptoplasty, the feeding and retaining of photosynthetically active chloroplasts from algae. The Plakobranchus species complex exhibits some of the longest kleptoplast retention and survival times under starvation conditions, but the contributions of these kleptoplasts to their survival and overall fitness have been widely debated. In this study we assessed the effects of starvation and light on the fitness of Plakobranchus cf. ianthobaptus and its kleptoplasts by placing starved individuals in eight daily average light treatments, ranging from near dark (2 µmol photon m-2 s-1) to ambient light (470 µmol photon m-2 s-1). Slug weight was used as a metric of fitness, and kleptoplast photosynthetic activity was determined via maximum quantum yield (Fv/Fm) by pulse-amplitude modulated fluorometry as a proxy for kleptoplast health. Plakobranchus individuals in near-dark and high light treatments (>160 µmol photon m-2 s-1) experienced significantly greater weight loss than those in low light (65 µmol photon m-2 s-1) and moderate light treatments (95-135 µmol photon m-2 s-1). Additionally, individuals in high light treatments experienced a rapid decline in kleptoplast photosynthetic activity, while all other treatments experienced minimal decline. This relationship between kleptoplast degradation and weight loss suggests an important link between fitness and kleptoplasty. Given the significant negative effects of ambient conditions, regular refreshment and replenishment of kleptoplasts or physiological or behavioral adjustments are likely employed for the benefits of kleptoplasty to be maintained.
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Christa G, Pütz L, Sickinger C, Melo Clavijo J, Laetz EMJ, Greve C, Serôdio J. Photoprotective Non-photochemical Quenching Does Not Prevent Kleptoplasts From Net Photoinactivation. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00121] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Laetz EMJ, Wägele H. How does temperature affect functional kleptoplasty? Comparing populations of the solar-powered sister-species Elysia timida Risso, 1818 and Elysia cornigera Nuttall, 1989 (Gastropoda: Sacoglossa). Front Zool 2018; 15:17. [PMID: 29760759 PMCID: PMC5937827 DOI: 10.1186/s12983-018-0264-y] [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: 10/11/2017] [Accepted: 04/06/2018] [Indexed: 01/03/2023] Open
Abstract
Background Despite widespread interest in solar-powered sea slugs (Sacoglossa: Gastropoda), relatively little is know about how they actually perform functional kleptoplasty. Sister-taxa Elysia timida and E. cornigera provide an ideal model system for investigating this phenomenon, since they feed on the same algal genus and only E. timida is capable of long-term kleptoplasty. Recent research has explored factors regarding functional kleptoplasty in E. timida, including their starvation longevity, digestive activity, autophagal response and photosynthetic efficiency under two different temperature conditions (18 °C and 21 °C). These studies revealed the trends E. timida displays regarding each factor during starvation as well as influences temperature has on some aspects of functional kleptoplasty. This study examines E. cornigera regarding each of these factors in an attempt to elucidate differences between each species that could explain their differing kleptoplastic abilities. Since both species naturally occur in 25 °C seawater (E. timida peak summer temperature, E. cornigera low winter temperature), each species was acclimatized to 25 °C to facilitate comparison and determine if these species exhibit physiological differences to starvation when under the same environmental conditions. Results When comparing the different E. timida temperature treatments, it becomes clear that increased temperatures compromise E. timida’s kleptoplastic abilities. Specimens acclimatized to 25 °C revealed shorter starvation longevities surviving an average 42.4 days compared to the 95.9 day average observed in specimens exposed to 18 °C. Each temperature treatment displayed a significantly different decrease throughout the starvation period in both, the rate of photosynthetic efficiency and in the decreasing functional kleptoplast abundance. Lysosomal abundances are assessed here as indicators of different aspects of metabolic activity, which could be correlated to temperature. E. cornigera, also acclimatized to 25 °C did not display significantly similar patterns as any of the E. timida temperature treatments, having fewer incorporated kleptoplasts, a higher lysosomal response to starvation, a faster decrease in photosynthetic efficiency and a lower starvation longevity. Conclusions These results confirm that each species has different physiological reactions to starvation and kleptoplast retention, even under the same conditions. While temperature affects aspects of functional kleptoplasty, it is likely not responsible for the differences in kleptoplastic abilities seen in these species. Electronic supplementary material The online version of this article (10.1186/s12983-018-0264-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elise Marie Jerschabek Laetz
- 1Zoological Research Museum Alexander Koenig, 160 Adenauerallee, 53113 Bonn, Germany.,2Institute for Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany
| | - Heike Wägele
- 1Zoological Research Museum Alexander Koenig, 160 Adenauerallee, 53113 Bonn, Germany
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12
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Laetz EMJ, Wägele H. Chloroplast digestion and the development of functional kleptoplasty in juvenile Elysia timida (Risso, 1818) as compared to short-term and non-chloroplast-retaining sacoglossan slugs. PLoS One 2017; 12:e0182910. [PMID: 29020043 PMCID: PMC5636068 DOI: 10.1371/journal.pone.0182910] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/26/2017] [Indexed: 01/13/2023] Open
Abstract
Sacoglossan sea slugs are the only metazoans known to perform functional kleptoplasty, the sequestration and retention of functional chloroplasts within their digestive gland cells. Remarkably, a few species with this ability can survive starvation periods of 3–12 months likely due to their stolen chloroplasts. There are no reports of kleptoplast transfer from mother slug to either eggs or juveniles, demonstrating that each animal must independently acquire its kleptoplasts and develop the ability to maintain them within its digestive gland. We present here an investigation into the development of functional kleptoplasty in a long-term kleptoplast retaining species, Elysia timida. Laboratory-reared juvenile slugs of different post-metamorphic ages were placed in starvation and compared to 5 known short-term retaining slug species and 5 non-retaining slug species. The subsequent results indicate that functional kleptoplasty is not performed by E. timida until after 15 days post-metamorphosis and that by 25 days, these animals outlive many of the short-term retention species. Digestive activity was also monitored using lysosomal abundance as an indicator, revealing different patterns in starving juveniles versus adults. Starved juveniles were reintroduced to food to determine any differences in digestive activity when starvation ends, resulting in an increase in the number of kleptoplasts, but no overall change in lysosomal activity. By revealing some of the changes that occur during early development in these animals, which begin as non-kleptoplast-retaining and grow into long-term retaining slugs, this investigation provides a basis for future inquiries into the origin and development of this remarkable ability.
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Affiliation(s)
- Elise Marie Jerschabek Laetz
- Center for Molecular Biodiversity Research (ZMB), Zoological Research Museum Alexander Koenig Adenauerallee 160 Bonn, Germany
- Institute for Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1 Bonn, Germany
- * E-mail:
| | - Heike Wägele
- Center for Molecular Biodiversity Research (ZMB), Zoological Research Museum Alexander Koenig Adenauerallee 160 Bonn, Germany
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Rauch C, Jahns P, Tielens AGM, Gould SB, Martin WF. On Being the Right Size as an Animal with Plastids. FRONTIERS IN PLANT SCIENCE 2017; 8:1402. [PMID: 28861094 PMCID: PMC5562673 DOI: 10.3389/fpls.2017.01402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
Plastids typically reside in plant or algal cells-with one notable exception. There is one group of multicellular animals, sea slugs in the order Sacoglossa, members of which feed on siphonaceous algae. The slugs sequester the ingested plastids in the cytosol of cells in their digestive gland, giving the animals the color of leaves. In a few species of slugs, including members of the genus Elysia, the stolen plastids (kleptoplasts) can remain morphologically intact for weeks and months, surrounded by the animal cytosol, which is separated from the plastid stroma by only the inner and outer plastid membranes. The kleptoplasts of the Sacoglossa are the only case described so far in nature where plastids interface directly with the metazoan cytosol. That makes them interesting in their own right, but it has also led to the idea that it might someday be possible to engineer photosynthetic animals. Is that really possible? And if so, how big would the photosynthetic organs of such animals need to be? Here we provide two sets of calculations: one based on a best case scenario assuming that animals with kleptoplasts can be, on a per cm2 basis, as efficient at CO2 fixation as maize leaves, and one based on 14CO2 fixation rates measured in plastid-bearing sea slugs. We also tabulate an overview of the literature going back to 1970 reporting direct measurements or indirect estimates of the CO2 fixing capabilities of Sacoglossan slugs with plastids.
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Affiliation(s)
- Cessa Rauch
- Molecular Evolution, Heinrich-Heine-UniversityDüsseldorf, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-UniversityDüsseldorf, Germany
| | - Aloysius G. M. Tielens
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht UniversityUtrecht, Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical CenterRotterdam, Netherlands
| | - Sven B. Gould
- Molecular Evolution, Heinrich-Heine-UniversityDüsseldorf, Germany
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Kleptoplast photosynthesis is nutritionally relevant in the sea slug Elysia viridis. Sci Rep 2017; 7:7714. [PMID: 28798379 PMCID: PMC5552801 DOI: 10.1038/s41598-017-08002-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 07/06/2017] [Indexed: 12/02/2022] Open
Abstract
Several sacoglossan sea slug species feed on macroalgae and incorporate chloroplasts into tubular cells of their digestive diverticula. We investigated the role of the “stolen” chloroplasts (kleptoplasts) in the nutrition of the sea slug Elysia viridis and assessed how their abundance, distribution and photosynthetic activity were affected by light and starvation. Elysia viridis individuals feeding on the macroalga Codium tomentosum were compared with starved specimens kept in dark and low light conditions. A combination of variable Chl a fluorescence and hyperspectral imaging, and HPLC pigment analysis was used to evaluate the spatial and temporal variability of photopigments and of the photosynthetic capacity of kleptoplasts. We show increased loss of weight and body length in dark-starved E. viridis as compared to low light-starved sea slugs. A more pronounced decrease in kleptoplast abundance and lower photosynthetic electron transport rates were observed in dark-starved sea slugs than in low light-starved animals. This study presents strong evidence of the importance of kleptoplast photosynthesis for the nutrition of E. viridis in periods of food scarcity. Deprived of photosynthates, E. viridis could accelerate the breakdown of kleptoplasts in the dark to satisfy its’ energy requirements.
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Rauch C, Christa G, de Vries J, Woehle C, Gould SB. Mitochondrial Genome Assemblies of Elysia timida and Elysia cornigera and the Response of Mitochondrion-Associated Metabolism during Starvation. Genome Biol Evol 2017; 9:1873-1879. [PMID: 28854599 PMCID: PMC5534330 DOI: 10.1093/gbe/evx129] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2017] [Indexed: 12/11/2022] Open
Abstract
Some sacoglossan sea slugs sequester functional plastids (kleptoplasts) from their food, which continue to fix CO2 in a light dependent manner inside the animals. In plants and algae, plastid and mitochondrial metabolism are linked in ways that reach beyond the provision of energy-rich carbon compounds through photosynthesis, but how slug mitochondria respond to starvation or alterations in plastid biochemistry has not been explored. We assembled the mitochondrial genomes of the plastid-sequestering sea slugs Elysia timida and Elysia cornigera from RNA-Seq data that was complemented with standard sequencing of mitochondrial DNA through primer walking. Our data confirm the sister species relationship of the two Sacoglossa and from the analysis of changes in mitochondrial-associated metabolism during starvation we speculate that kleptoplasts might aid in the rerouting or recycling of reducing power independent of, yet maybe improved by, photosynthesis.
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Affiliation(s)
- Cessa Rauch
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Germany
| | - Gregor Christa
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Germany
- Department of Biology and CESAM, University of Aveiro, Portugal
| | - Jan de Vries
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Germany
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christian Woehle
- Institute for Genomic Microbiology, Christian-Albrechts-University Kiel, Germany
| | - Sven B. Gould
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Germany
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