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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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Kleptoplast distribution, photosynthetic efficiency and sequestration mechanisms in intertidal benthic foraminifera. THE ISME JOURNAL 2022; 16:822-832. [PMID: 34635793 PMCID: PMC8857221 DOI: 10.1038/s41396-021-01128-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 11/19/2022]
Abstract
Foraminifera are ubiquitously distributed in marine habitats, playing a major role in marine sediment carbon sequestration and the nitrogen cycle. They exhibit a wide diversity of feeding and behavioural strategies (heterotrophy, autotrophy and mixotrophy), including species with the ability of sequestering intact functional chloroplasts from their microalgal food source (kleptoplastidy), resulting in a mixotrophic lifestyle. The mechanisms by which kleptoplasts are integrated and kept functional inside foraminiferal cytosol are poorly known. In our study, we investigated relationships between feeding strategies, kleptoplast spatial distribution and photosynthetic functionality in two shallow-water benthic foraminifera (Haynesina germanica and Elphidium williamsoni), both species feeding on benthic diatoms. We used a combination of observations of foraminiferal feeding behaviour, test morphology, cytological TEM-based observations and HPLC pigment analysis, with non-destructive, single-cell level imaging of kleptoplast spatial distribution and PSII quantum efficiency. The two species showed different feeding strategies, with H. germanica removing diatom content at the foraminifer's apertural region and E. williamsoni on the dorsal site. All E. williamsoni parameters showed that this species has higher autotrophic capacity albeit both feeding on benthic diatoms. This might represent two different stages in the evolutionary process of establishing a permanent symbiotic relationship, or may reflect different trophic strategies.
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Aoki R, Matsunaga S. A Photosynthetic Animal: A Sacoglossan Sea Slug that Steals Chloroplasts. CYTOLOGIA 2021. [DOI: 10.1508/cytologia.86.103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ryota Aoki
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
| | - Sachihiro Matsunaga
- Laboratory of Integrated Biology, Department of Integrated Biosciences, Graduate School of Frontier Sciences
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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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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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Rey F, Costa ED, Campos AM, Cartaxana P, Maciel E, Domingues P, Domingues MRM, Calado R, Cruz S. Kleptoplasty does not promote major shifts in the lipidome of macroalgal chloroplasts sequestered by the sacoglossan sea slug Elysia viridis. Sci Rep 2017; 7:11502. [PMID: 28904377 PMCID: PMC5597624 DOI: 10.1038/s41598-017-12008-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 08/31/2017] [Indexed: 01/19/2023] Open
Abstract
Sacoglossan sea slugs, also known as crawling leaves due to their photosynthetic activity, are highly selective feeders that incorporate chloroplasts from specific macroalgae. These “stolen” plastids - kleptoplasts - are kept functional inside animal cells and likely provide an alternative source of energy to their host. The mechanisms supporting the retention and functionality of kleptoplasts remain unknown. A lipidomic mass spectrometry-based analysis was performed to study kleptoplasty of the sacoglossan sea slug Elysia viridis fed with Codium tomentosum. Total lipid extract of both organisms was fractionated. The fraction rich in glycolipids, exclusive lipids from chloroplasts, and the fraction rich in betaine lipids, characteristic of algae, were analysed using hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-LC-MS). This approach allowed the identification of 81 molecular species, namely galactolipids (8 in both organisms), sulfolipids (17 in C. tomentosum and 13 in E. viridis) and betaine lipids (51 in C. tomentosum and 41 in E. viridis). These lipid classes presented similar lipidomic profiles in C. tomentosum and E. viridis, indicating that the necessary mechanisms to perform photosynthesis are preserved during the process of endosymbiosis. The present study shows that there are no major shifts in the lipidome of C. tomentosum chloroplasts sequestered by E. viridis.
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Affiliation(s)
- Felisa Rey
- Departamento de Biologia & CESAM & ECOMARE, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Elisabete da Costa
- Centro de Espetrometria de Massa, Departamento de Química & QOPNA, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Ana M Campos
- Centro de Espetrometria de Massa, Departamento de Química & QOPNA, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Paulo Cartaxana
- Departamento de Biologia & CESAM & ECOMARE, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Elisabete Maciel
- Departamento de Biologia & CESAM & ECOMARE, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.,Centro de Espetrometria de Massa, Departamento de Química & QOPNA, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Pedro Domingues
- Centro de Espetrometria de Massa, Departamento de Química & QOPNA, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - M Rosário M Domingues
- Centro de Espetrometria de Massa, Departamento de Química & QOPNA, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Ricardo Calado
- Departamento de Biologia & CESAM & ECOMARE, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Sónia Cruz
- Departamento de Biologia & CESAM & ECOMARE, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
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Stamatakis K, Vayenos D, Kotakis C, Gast RJ, Papageorgiou GC. The extraordinary longevity of kleptoplasts derived from the Ross Sea haptophyte Phaeocystis antarctica within dinoflagellate host cells relates to the diminished role of the oxygen-evolving Photosystem II and to supplementary light harvesting by mycosporine-like amino acid/s. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:189-195. [PMID: 27940021 DOI: 10.1016/j.bbabio.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 11/30/2022]
Abstract
The haptophyte Phaeocystis antarctica and the novel Ross Sea dinoflagellate that hosts kleptoplasts derived from P. antarctica (RSD; R.J. Gast et al., 2006, J. Phycol. 42 233-242) were compared for photosynthetic light harvesting and for oxygen evolution activity. Both chloroplasts and kleptoplasts emit chlorophyll a (Chl a) fluorescence peaking at 683nm (F683) at 277K and at 689 (F689) at 77K. Second derivative analysis of the F689 band at 77K revealed two individual contributions centered at 683nm (Fi-683) and at 689 (Fi-689). Using the p-nitrothiophenol (p-NTP) treatment of Kobayashi et al. (Biochim. Biophys. Acta 423 (1976) 80-90) to differentiate between Photosystem (PS) II and I fluorescence emissions, we could identify PS II as the origin of Fi-683 and PS I as the origin of Fi-689. Both emissions could be excited not only by Chl a-selective light (436nm) but also by mycosporine-like amino acids (MAAs)-selective light (345nm). This suggests that a fraction of MAAs must be proximal to Chls a and, therefore, located within the plastids. On the basis of second derivative fluorescence spectra at 77K, of p-NTP resolved fluorescence spectra, as well as of PSII-driven oxygen evolution activities, PS II appears substantially less active (~1/5) in dinoflagellate kleptoplasts than in P. antarctica chloroplasts. We suggest that a diminished role of PS II, a known source of reactive oxygen species, and a diminished dependence on nucleus-encoded light-harvesting proteins, due to supplementary light-harvesting by MAAs, may account for the extraordinary longevity of RSD kleptoplasts.
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Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, NCSR "Demokritos", Aghia Paraskevi, Attikis, Greece.
| | - Dimitris Vayenos
- Institute of Biosciences and Applications, NCSR "Demokritos", Aghia Paraskevi, Attikis, Greece
| | - Christos Kotakis
- Institute of Biosciences and Applications, NCSR "Demokritos", Aghia Paraskevi, Attikis, Greece; Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary; Kontakeika, Karlovassi Samos, GR-83200, Greece
| | - Rebecca J Gast
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - George C Papageorgiou
- Institute of Biosciences and Applications, NCSR "Demokritos", Aghia Paraskevi, Attikis, Greece
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Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway). Appl Environ Microbiol 2016; 82:1868-1880. [PMID: 26746718 DOI: 10.1128/aem.03208-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/05/2016] [Indexed: 11/20/2022] Open
Abstract
The Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 μm) from a depth of 25 m was determined using 454 sequencing of the 18S V4 region amplified from both DNA and RNA. The compositional changes throughout the year were assessed in relation to in situ fjord environmental conditions. Size fractionation analyses of chlorophyll a showed that the photosynthetic biomass was dominated by small cells (<10 μm) most of the year but that larger cells dominated during the spring and summer. The winter and early-spring communities were more diverse than the spring and summer/autumn communities. Dinophyceae were predominant throughout the year. The Arctic Micromonas ecotype was abundant mostly in the early-bloom and fall periods, whereas heterotrophs, such as marine stramenopiles (MASTs), Picozoa, and the parasitoid marine alveolates (MALVs), displayed higher relative abundance in the winter than in other seasons. Our results emphasize the extreme seasonality of Arctic microbial eukaryotic communities driven by the light regime and nutrient availability but point to the necessity of a thorough knowledge of hydrography for full understanding of their succession and variability.
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Christa G, Händeler K, Kück P, Vleugels M, Franken J, Karmeinski D, Wägele H. Phylogenetic evidence for multiple independent origins of functional kleptoplasty in Sacoglossa (Heterobranchia, Gastropoda). ORG DIVERS EVOL 2014. [DOI: 10.1007/s13127-014-0189-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Lipid accumulation during the establishment of kleptoplasty in Elysia chlorotica. PLoS One 2014; 9:e97477. [PMID: 24828251 PMCID: PMC4020867 DOI: 10.1371/journal.pone.0097477] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/19/2014] [Indexed: 11/19/2022] Open
Abstract
The establishment of kleptoplasty (retention of "stolen plastids") in the digestive tissue of the sacoglossan Elysia chlorotica Gould was investigated using transmission electron microscopy. Cellular processes occurring during the initial exposure to plastids were observed in laboratory raised animals ranging from 1-14 days post metamorphosis (dpm). These observations revealed an abundance of lipid droplets (LDs) correlating to plastid abundance. Starvation of animals resulted in LD and plastid decay in animals <5 dpm that had not yet achieved permanent kleptoplasty. Animals allowed to feed on algal prey (Vaucheria litorea C. Agardh) for 7 d or greater retained stable plastids resistant to cellular breakdown. Lipid analysis of algal and animal samples supports that these accumulating LDs may be of plastid origin, as the often algal-derived 20∶5 eicosapentaenoic acid was found in high abundance in the animal tissue. Subsequent culturing of animals in dark conditions revealed a reduced ability to establish permanent kleptoplasty in the absence of photosynthetic processes, coupled with increased mortality. Together, these data support an important role of photosynthetic lipid production in establishing and stabilizing this unique animal kleptoplasty.
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Serôdio J, Cruz S, Cartaxana P, Calado R. Photophysiology of kleptoplasts: photosynthetic use of light by chloroplasts living in animal cells. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130242. [PMID: 24591722 DOI: 10.1098/rstb.2013.0242] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Kleptoplasty is a remarkable type of photosynthetic association, resulting from the maintenance of functional chloroplasts--the 'kleptoplasts'--in the tissues of a non-photosynthetic host. It represents a biologically unique condition for chloroplast and photosynthesis functioning, occurring in different phylogenetic lineages, namely dinoflagellates, ciliates, foraminiferans and, most interestingly, a single taxon of metazoans, the sacoglossan sea slugs. In the case of sea slugs, chloroplasts from macroalgae are often maintained as intracellular organelles in cells of these marine gastropods, structurally intact and photosynthetically competent for extended periods of time. Kleptoplasty has long attracted interest owing to the longevity of functional kleptoplasts in the absence of the original algal nucleus and the limited number of proteins encoded by the chloroplast genome. This review updates the state-of-the-art on kleptoplast photophysiology, focusing on the comparative analysis of the responses to light of the chloroplasts when in their original, macroalgal cells, and when sequestered in animal cells and functioning as kleptoplasts. It covers fundamental but ecologically relevant aspects of kleptoplast light responses, such as the occurrence of photoacclimation in hospite, operation of photoprotective processes and susceptibility to photoinhibition. Emphasis is given to host-mediated processes unique to kleptoplastic associations, reviewing current hypotheses on behavioural photoprotection and host-mediated enhancement of photosynthetic performance, and identifying current gaps in sacoglossan kleptoplast photophysiology research.
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Affiliation(s)
- João Serôdio
- Departamento de Biologia and CESAM, Universidade de Aveiro, , Campus Universitário de Santiago, Aveiro 3810-193, Portugal
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12
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Cruz S, Calado R, Serôdio J, Cartaxana P. Crawling leaves: photosynthesis in sacoglossan sea slugs. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3999-4009. [PMID: 23846876 DOI: 10.1093/jxb/ert197] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Some species of sacoglossan sea slugs can maintain functional chloroplasts from specific algal food sources in the cells of their digestive diverticula. These 'stolen' chloroplasts (kleptoplasts) can survive in the absence of the plant cell and continue to photosynthesize, in some cases for as long as one year. Within the Metazoa, this phenomenon (kleptoplasty) seems to have only evolved among sacoglossan sea slugs. Known for over a century, the mechanisms of interaction between the foreign organelle and its host animal cell are just now starting to be unravelled. In the study of sacoglossan sea slugs as photosynthetic systems, it is important to understand their relationship with light. This work reviews the state of knowledge on autotrophy as a nutritional source for sacoglossans and the strategies they have developed to avoid excessive light, with emphasis to the behavioural and physiological mechanisms suggested to be involved in the photoprotection of kleptoplasts. A special focus is given to the advantages and drawbacks of using pulse amplitude modulated fluorometry in photobiological studies addressing sacoglossan sea slugs. Finally, the classification of photosynthetic sacoglossan sea slugs according to their ability to retain functional kleptoplasts and the importance of laboratory culturing of these organisms are briefly discussed.
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Affiliation(s)
- Sónia Cruz
- Departamento de Biologia and CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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Händeler K, Wägele H, Wahrmund U, Rüdinger M, Knoop V. Slugs' last meals: molecular identification of sequestered chloroplasts from different algal origins in Sacoglossa (Opisthobranchia, Gastropoda). Mol Ecol Resour 2013; 10:968-78. [PMID: 21565106 DOI: 10.1111/j.1755-0998.2010.02853.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Some sacoglossan sea slugs have become famous for their unique capability to extract and incorporate functional chloroplasts from algal food organisms (mainly Ulvophyceae) into their gut cells. The functional incorporation of the so-called kleptoplasts allows the slugs to rely on photosynthetic products for weeks to months, enabling them to survive long periods of food shortage over most of their life-span. The algal food spectrum providing kleptoplasts as temporary, non-inherited endosymbionts appears to vary among sacoglossan slugs, but detailed knowledge is sketchy or unavailable. Accurate identification of algal donor species, which provide the chloroplasts for long-term retention is of primary importance to elucidate the biochemical mechanisms allowing long-term functionality of the captured chloroplast in the foreign animal cell environment. Whereas some sacoglossans forage on a variety of algal species, (e.g. Elysia crispata and E. viridis) others are more selective. Hence, characterizing the range of functional sacoglossan-chloroplast associations in nature is a prerequisite to understand the basis of this enigmatic endosymbiosis. Here, we present a suitable chloroplast gene (tufA) as a marker, which allows identification of the respective algal kleptoplast donor taxa by analysing DNA from whole animals. This novel approach allows identification of donor algae on genus or even species level, thus providing evidence for the taxonomic range of food organisms. We report molecular evidence that chloroplasts from different algal sources are simultaneously incorporated in some species of Elysia. NeigborNet analyses for species assignments are preferred over tree reconstruction methods because the former allow more reliable statements on species identification via barcoding, or rather visualize alternative allocations not to be seen in the latter.
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Affiliation(s)
- Katharina Händeler
- Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany Institut für Zelluläre und Molekulare Botanik, Bonn, Germany
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Martin R, Walther P, Tomaschko KH. Phagocytosis of algal chloroplasts by digestive gland cells in the photosynthesis-capable slug Elysia timida (Mollusca, Opisthobranchia, Sacoglossa). ZOOMORPHOLOGY 2012. [DOI: 10.1007/s00435-012-0184-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Laboratory culturing of Elysia chlorotica reveals a shift from transient to permanent kleptoplasty. Symbiosis 2012. [DOI: 10.1007/s13199-012-0192-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Yamaoka I, Kikuchi T, Arata T, Kobayashi E. Organ preservation using a photosynthetic solution. Transplant Res 2012; 1:2. [PMID: 23369195 PMCID: PMC3552571 DOI: 10.1186/2047-1440-1-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 04/24/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Organs harvested from a body lapsing into circulatory deficit are exposed to low O2/high CO2, and reach a critical point where original functionality after transplantation is unlikely. The present study evaluates the effect of respiratory assistance using Chlorella photosynthesis on preservation of the rat pancreas from the viewpoint of donation after cardiac death (DCD). METHODS Gas was exchanged through the peritoneum of rats under controlled ventilation with or without Chlorella photosynthetic respiratory assistance. A gas permeable pouch containing Chlorella in solution was placed in the peritoneum and then the space between the pouch and the peritoneum was filled with an emulsified perfluorocarbon gas carrier. Rat DCD pancreases procured 3 h after cardiac arrest were preserved for 30 min in a cold or mildly hypothermic environment or in a mildly hypothermic environment with photosynthetic respiratory support. The pancreases were then heterotopically transplanted into rats with STZ-induced diabetes. RESULTS Levels of blood oxygen (PaO2) and carbon dioxide (PaCO2) increased and significantly decreased, respectively, in rats with mechanically reduced ventilation and rats given intraperitoneal photosynthetic respiratory support when compared with those without such support. Transplantation with DCD pancreases that had been stored under photosynthetic respiratory support resulted in the survival of all rats, which is impossible to achieve using pancreases that have been maintained statically in cold storage. CONCLUSION Respiratory assistance using photosynthesis helps to improve not only blood gas status in the event of respiratory insufficiency, but also graft recovery after pancreas transplantation with a DCD pancreas that has been damaged by prolonged warm ischemia.
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Affiliation(s)
- Ippei Yamaoka
- Otsuka Pharmaceutical Factory, Inc, 115 Kuguhara, Tateiwa, Muya-cho, Naruto, Tokushima, 772-8601, Japan
| | - Takeshi Kikuchi
- Otsuka Pharmaceutical Factory, Inc, 115 Kuguhara, Tateiwa, Muya-cho, Naruto, Tokushima, 772-8601, Japan
| | - Tomohiro Arata
- Otsuka Pharmaceutical Factory, Inc, 115 Kuguhara, Tateiwa, Muya-cho, Naruto, Tokushima, 772-8601, Japan
| | - Eiji Kobayashi
- Otsuka Pharmaceutical Factory, Inc, 115 Kuguhara, Tateiwa, Muya-cho, Naruto, Tokushima, 772-8601, Japan.,Center for Development of Advanced Medical Technology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
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Gross J, Bhattacharya D, Pelletreau KN, Rumpho ME, Reyes-Prieto A. Secondary and Tertiary Endosymbiosis and Kleptoplasty. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2012. [DOI: 10.1007/978-94-007-2920-9_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Abstract
The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae ("Oophila amblystomatis" Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26-44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell-cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures.
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Pelletreau KN, Bhattacharya D, Price DC, Worful JM, Moustafa A, Rumpho ME. Sea slug kleptoplasty and plastid maintenance in a metazoan. PLANT PHYSIOLOGY 2011; 155:1561-1565. [PMID: 21346171 PMCID: PMC3091133 DOI: 10.1104/pp.111.174078] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 02/20/2011] [Indexed: 05/29/2023]
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Rumpho ME, Pelletreau KN, Moustafa A, Bhattacharya D. The making of a photosynthetic animal. J Exp Biol 2011; 214:303-11. [PMID: 21177950 PMCID: PMC3008634 DOI: 10.1242/jeb.046540] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2010] [Indexed: 11/20/2022]
Abstract
Symbiotic animals containing green photobionts challenge the common perception that only plants are capable of capturing the sun's rays and converting them into biological energy through photoautotrophic CO(2) fixation (photosynthesis). 'Solar-powered' sacoglossan molluscs, or sea slugs, have taken this type of symbiotic association one step further by solely harboring the photosynthetic organelle, the plastid (=chloroplast). One such sea slug, Elysia chlorotica, lives as a 'plant' when provided with only light and air as a result of acquiring plastids during feeding on its algal prey Vaucheria litorea. The captured plastids (kleptoplasts) are retained intracellularly in cells lining the digestive diverticula of the sea slug, a phenomenon sometimes referred to as kleptoplasty. Photosynthesis by the plastids provides E. chlorotica with energy and fixed carbon for its entire lifespan of ~10 months. The plastids are not transmitted vertically (i.e. are absent in eggs) and do not undergo division in the sea slug. However, de novo protein synthesis continues, including plastid- and nuclear-encoded plastid-targeted proteins, despite the apparent absence of algal nuclei. Here we discuss current data and provide hypotheses to explain how long-term photosynthetic activity is maintained by the kleptoplasts. This fascinating 'green animal' provides a unique model to study the evolution of photosynthesis in a multicellular heterotrophic organism.
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Affiliation(s)
- Mary E Rumpho
- Department of Molecular and Biomedical Sciences, 5735 Hitchner Hall, University of Maine, Orono, ME 04469, USA.
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Johnson MD. The acquisition of phototrophy: adaptive strategies of hosting endosymbionts and organelles. PHOTOSYNTHESIS RESEARCH 2011; 107:117-132. [PMID: 20405214 DOI: 10.1007/s11120-010-9546-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 03/22/2010] [Indexed: 05/29/2023]
Abstract
Many non-photosynthetic species of protists and metazoans are capable of hosting viable algal endosymbionts or their organelles through adaptations of phagocytic pathways. A form of mixotrophy combining phototrophy and heterotrophy, acquired phototrophy (AcPh) encompasses a suite of endosymbiotic and organelle retention interactions, that range from facultative to obligate. AcPh is a common phenomenon in aquatic ecosystems, with endosymbiotic associations generally more prevalent in nutrient poor environments, and organelle retention typically associated with more productive ones. All AcPhs benefit from enhanced growth due to access to photosynthetic products; however, the degree of metabolic integration and dependency in the host varies widely. AcPh is found in at least four of the major eukaryotic supergroups, and is the driving force in the evolution of secondary and tertiary plastid acquisitions. Mutualistic resource partitioning characterizes most algal endosymbiotic interactions, while organelle retention is a form of predation, characterized by nutrient flow (i.e., growth) in one direction. AcPh involves adaptations to recognize specific prey or endosymbionts and to house organelles or endosymbionts within the endomembrane system but free from digestion. In many cases, hosts depend upon AcPh for the production of essential nutrients, many of which remain obscure. The practice of AcPh has led to multiple independent secondary and tertiary plastid acquisition events among several eukaryote lineages, giving rise to the diverse array of algae found in modern aquatic ecosystems. This article highlights those AcPhs that are model research organisms for both metazoans and protists. Much of the basic biology of AcPhs remains enigmatic, particularly (1) which essential nutrients or factors make certain forms of AcPh obligatory, (2) how hosts regulate and manipulate endosymbionts or sequestered organelles, and (3) what genomic imprint, if any, AcPh leaves on non-photosynthetic host species.
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Affiliation(s)
- Matthew D Johnson
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
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Wouters J, Raven JA, Minnhagen S, Janson S. The luggage hypothesis: Comparisons of two phototrophic hosts with nitrogen-fixing cyanobacteria and implications for analogous life strategies for kleptoplastids/secondary symbiosis in dinoflagellates. Symbiosis 2009. [DOI: 10.1007/s13199-009-0020-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Horizontal gene transfer of the algal nuclear gene psbO to the photosynthetic sea slug Elysia chlorotica. Proc Natl Acad Sci U S A 2008; 105:17867-71. [PMID: 19004808 DOI: 10.1073/pnas.0804968105] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The sea slug Elysia chlorotica acquires plastids by ingestion of its algal food source Vaucheria litorea. Organelles are sequestered in the mollusc's digestive epithelium, where they photosynthesize for months in the absence of algal nucleocytoplasm. This is perplexing because plastid metabolism depends on the nuclear genome for >90% of the needed proteins. Two possible explanations for the persistence of photosynthesis in the sea slug are (i) the ability of V. litorea plastids to retain genetic autonomy and/or (ii) more likely, the mollusc provides the essential plastid proteins. Under the latter scenario, genes supporting photosynthesis have been acquired by the animal via horizontal gene transfer and the encoded proteins are retargeted to the plastid. We sequenced the plastid genome and confirmed that it lacks the full complement of genes required for photosynthesis. In support of the second scenario, we demonstrated that a nuclear gene of oxygenic photosynthesis, psbO, is expressed in the sea slug and has integrated into the germline. The source of psbO in the sea slug is V. litorea because this sequence is identical from the predator and prey genomes. Evidence that the transferred gene has integrated into sea slug nuclear DNA comes from the finding of a highly diverged psbO 3' flanking sequence in the algal and mollusc nuclear homologues and gene absence from the mitochondrial genome of E. chlorotica. We demonstrate that foreign organelle retention generates metabolic novelty ("green animals") and is explained by anastomosis of distinct branches of the tree of life driven by predation and horizontal gene transfer.
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