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Quevarec L, Brasseur G, Aragnol D, Robaglia C. Tracking the early events of photosymbiosis evolution. TRENDS IN PLANT SCIENCE 2024; 29:406-412. [PMID: 38016867 DOI: 10.1016/j.tplants.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/19/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023]
Abstract
Oxygenic photosynthesis evolved in cyanobacteria around 3.2 giga-annum (Ga) ago and was acquired by eukaryotes starting around 1.8 Ga ago by endosymbiosis. Photosymbiosis results either from integration of a photosynthetic bacteria by heterotrophic eukaryotes (primary photosymbiosis) or by successive integration of photosymbiotic eukaryotes by heterotrophic eukaryotes (secondary photosymbiosis). Primary endosymbiosis is thought to have been a rare event, whereas secondary and higher-order photosymbiosis evolved multiple times independently in different taxa. Despite its recurrent evolution, the molecular and cellular mechanisms underlying photosymbiosis are unknown. In this opinion, we discuss the primary events leading to the establishment of photosymbiosis, and we present recent research suggesting that, in some cases, domestication occurred instead of symbiosis, and how oxygen and host immunity can be involved in symbiont maintenance.
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Affiliation(s)
- Loïc Quevarec
- Aix Marseille Université, CEA, CNRS, BIAM, Luminy Génétique et Biophysique des Plantes, 13009 Marseille, France; Laboratoire de Chimie Bactérienne, IMM, CNRS, Aix-Marseille Université, 13402 Marseille, France
| | - Gaël Brasseur
- Laboratoire de Chimie Bactérienne, IMM, CNRS, Aix-Marseille Université, 13402 Marseille, France
| | - Denise Aragnol
- Aix Marseille Université, CEA, CNRS, BIAM, Luminy Génétique et Biophysique des Plantes, 13009 Marseille, France
| | - Christophe Robaglia
- Aix Marseille Université, CEA, CNRS, BIAM, Luminy Génétique et Biophysique des Plantes, 13009 Marseille, France.
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2
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Song Q, Zhao F, Hou L, Miao M. Cellular interactions and evolutionary origins of endosymbiotic relationships with ciliates. THE ISME JOURNAL 2024; 18:wrae117. [PMID: 38916437 PMCID: PMC11253213 DOI: 10.1093/ismejo/wrae117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/26/2024] [Accepted: 06/21/2024] [Indexed: 06/26/2024]
Abstract
As unicellular predators, ciliates engage in close associations with diverse microbes, laying the foundation for the establishment of endosymbiosis. Originally heterotrophic, ciliates demonstrate the ability to acquire phototrophy by phagocytizing unicellular algae or by sequestering algal plastids. This adaptation enables them to gain photosynthate and develop resistance to unfavorable environmental conditions. The integration of acquired phototrophy with intrinsic phagotrophy results in a trophic mode known as mixotrophy. Additionally, ciliates can harbor thousands of bacteria in various intracellular regions, including the cytoplasm and nucleus, exhibiting species specificity. Under prolonged and specific selective pressure within hosts, bacterial endosymbionts evolve unique lifestyles and undergo particular reductions in metabolic activities. Investigating the research advancements in various endosymbiotic cases within ciliates will contribute to elucidate patterns in cellular interaction and unravel the evolutionary origins of complex traits.
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Affiliation(s)
- Qi Song
- Medical School, University of Chinese Academy of Sciences, No. 1 Yanqihu East Road, Huairou District, Beijing 100049, China
| | - Fangqing Zhao
- Medical School, University of Chinese Academy of Sciences, No. 1 Yanqihu East Road, Huairou District, Beijing 100049, China
- Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, No. 1 Xiangshan Road, Hangzhou 310024, China
| | - Lina Hou
- Medical School, University of Chinese Academy of Sciences, No. 1 Yanqihu East Road, Huairou District, Beijing 100049, China
| | - Miao Miao
- Medical School, University of Chinese Academy of Sciences, No. 1 Yanqihu East Road, Huairou District, Beijing 100049, China
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3
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Rotterová J, Edgcomb VP, Čepička I, Beinart R. Anaerobic Ciliates as a Model Group for Studying Symbioses in Oxygen-depleted Environments. J Eukaryot Microbiol 2022; 69:e12912. [PMID: 35325496 DOI: 10.1111/jeu.12912] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Anaerobiosis has independently evolved in multiple lineages of ciliates, allowing them to colonize a variety of anoxic and oxygen-depleted habitats. Anaerobic ciliates commonly form symbiotic relationships with various prokaryotes, including methanogenic archaea and members of several bacterial groups. The hypothesized functions of these ecto- and endosymbionts include the symbiont utilizing the ciliate's fermentative end-products to increase host's anaerobic metabolic efficiency, or the symbiont directly providing the host with energy by denitrification or photosynthesis. The host, in turn, may protect the symbiont from competition, the environment, and predation. Despite rapid advances in sampling, molecular, and microscopy methods, as well as the associated broadening of the known diversity of anaerobic ciliates, many aspects of these ciliate symbioses, including host-specificity and co-evolution, remain largely unexplored. Nevertheless, with the number of comparative genomic and transcriptomic analyses targeting anaerobic ciliates and their symbionts on the rise, insights into the nature of these symbioses and the evolution of the ciliate transition to obligate anaerobiosis continue to deepen. This review summarizes the current body of knowledge regarding the complex nature of symbioses in anaerobic ciliates, the diversity of these symbionts, their role in the evolution of ciliate anaerobiosis and their significance in ecosystem-level processes.
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Affiliation(s)
- Johana Rotterová
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA.,Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Virginia P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Ivan Čepička
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Roxanne Beinart
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
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Szpakowska B, Świerk D, Pajchrowska M, Gołdyn R. Verifying the usefulness of macrophytes as an indicator of the status of small waterbodies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149279. [PMID: 34340089 DOI: 10.1016/j.scitotenv.2021.149279] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/22/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Small waterbodies are characterised by a high variability of physicochemical parameters. This has an impact on aquatic macrophytes, which are functional components of aquatic ecosystems that also exert a strong influence on other components of these ecosystems. Therefore, their importance in the classification of reservoirs is unquestionable. Unfortunately, the hydromacrophytes found in nutrient-rich small waterbodies in rural areas have a fairly wide ecological scale and are not suitable for a more accurate assessment of these reservoirs. In addition, indicators derived from the classification of lakes, such as phosphorus, nitrogen, chlorophyll-a, organic matter and trophic state indices, have turned out to be of little use in the assessment of small waterbodies. Only a canonical analysis taking into account both environmental variables and the occurring plant species allows satisfactory results to be obtained. Six small waterbodies located in the rural landscape of the Greater Poland Region were studied over three years. 115 plant taxa, 15 of which are hydromacrophytes, were found in the reservoirs and in their immediate vicinity. Three types of small waterbodies were identified in the CCA assessment: (i) those with high TOC, COD and ammonium nitrogen contents, dominated by pleustophytes, and in a saprotrophic state, (ii) those with high nutrient concentrations, dominated by phytoplankton, with a lack of macrophytes or with nymphaeids present, and in a hypereutrophic state, and (iii) those dominated by submerged macrophytes with low chlorophyll-a content, and in a eutrophic state. Thus, macrophytes turn out to be good indicators which support other variables in the classification of small waterbodies.
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Affiliation(s)
- Barbara Szpakowska
- Department of Landscape Architecture, Poznań University of Life Sciences, Dąbrowskiego 159, 60-594 Poznań, Poland
| | - Dariusz Świerk
- Department of Landscape Architecture, Poznań University of Life Sciences, Dąbrowskiego 159, 60-594 Poznań, Poland.
| | - Maria Pajchrowska
- Department of Landscape Architecture, Poznań University of Life Sciences, Dąbrowskiego 159, 60-594 Poznań, Poland
| | - Ryszard Gołdyn
- Department of Water Protection, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
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Muñoz-Gómez SA, Kreutz M, Hess S. A microbial eukaryote with a unique combination of purple bacteria and green algae as endosymbionts. SCIENCE ADVANCES 2021; 7:eabg4102. [PMID: 34117067 PMCID: PMC8195481 DOI: 10.1126/sciadv.abg4102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/27/2021] [Indexed: 05/08/2023]
Abstract
Oxygenic photosynthesizers (cyanobacteria and eukaryotic algae) have repeatedly become endosymbionts throughout evolution. In contrast, anoxygenic photosynthesizers (e.g., purple bacteria) are exceedingly rare as intracellular symbionts. Here, we report on the morphology, ultrastructure, lifestyle, and metagenome of the only "purple-green" eukaryote known. The ciliate Pseudoblepharisma tenue harbors green algae and hundreds of genetically reduced purple bacteria. The latter represent a new candidate species of the Chromatiaceae that lost known genes for sulfur dissimilation. The tripartite consortium is physiologically complex because of the versatile energy metabolism of each partner but appears to be ecologically specialized as it prefers hypoxic sediments. The emergent niche of this complex symbiosis is predicted to be a partial overlap of each partners' niches and may be largely defined by anoxygenic photosynthesis and possibly phagotrophy. This purple-green ciliate thus represents an extraordinary example of how symbiosis merges disparate physiologies and allows emergent consortia to create novel ecological niches.
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Affiliation(s)
- Sergio A Muñoz-Gómez
- Institute for Zoology, Cologne Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany.
- Center for Mechanism of Evolution, The Biodesign Institute, School of Life Sciences, Arizona State University, 727 E. Tyler St., Tempe, AZ 85281-5001, USA
| | - Martin Kreutz
- Private Laboratory, Am See 27, 78465 Constance, Germany
| | - Sebastian Hess
- Institute for Zoology, Cologne Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany.
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Biswakarma J, Kang K, Schenkeveld WDC, Kraemer SM, Hering JG, Hug SJ. Catalytic effects of photogenerated Fe(II) on the ligand-controlled dissolution of Iron(hydr)oxides by EDTA and DFOB. CHEMOSPHERE 2021; 263:128188. [PMID: 33297154 DOI: 10.1016/j.chemosphere.2020.128188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 06/12/2023]
Abstract
Low bioavailability of iron due to poor solubility of iron(hydr)oxides limits the growth of microorganisms and plants in soils and aquatic environments. Previous studies described accelerated dissolution of iron(hydr)oxides under continuous illumination, but did not distinguish between photoreductive dissolution and non-reductive processes in which photogenerated Fe(II) catalyzes ligand-controlled dissolution. Here we show that short illuminations (5-15 min) accelerate the dissolution of iron(hydr)oxides by ligands during subsequent dark periods under anoxic conditions. Suspensions of lepidocrocite (Lp) and goethite (Gt) (1.13 mM) with 50 μM EDTA or DFOB were illuminated with UV-A light of comparable intensity to sunlight (pH 7.0, bicarbonate-CO2 buffered solutions). During illumination, the rate of Fe(II) production was highest with Gt-EDTA; followed by Lp-EDTA > Lp-DFOB > Lp > Gt-DFOB > Gt. Under anoxic conditions, photochemically produced Fe(II) increased dissolution rates during subsequent dark periods by factors of 10-40 and dissolved Fe(III) reached 50 μM with DFOB and EDTA. Under oxic conditions, dissolution rates increased by factors of 3-5 only during illumination. With DFOB dissolved Fe(III) reached 35 μM after 10 h of illumination, while with EDTA it peaked at 15 μM and then decreased to below 2 μM. The observations are explained and discussed based on a kinetic model. The results suggest that in anoxic bottom water of ponds and lakes, or in microenvironments of algal blooms, short illuminations can dramatically increase the bioavailability of iron by Fe(II)-catalyzed ligand-controlled dissolution. In oxic environments, photostable ligands such as DFOB can maintain Fe(III) in solution during extended illumination.
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Affiliation(s)
- Jagannath Biswakarma
- Swiss Federal Institute of Technology (ETH) Zurich, IBP, CH-8092, Zürich, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland
| | - Kyounglim Kang
- University of Vienna, Dept. of Environmental Geosciences, 1090, Vienna, Austria
| | - Walter D C Schenkeveld
- Copernicus Institute of Sustainable Development, Faculty of Geosciences, Utrecht University, 3584, CB Utrecht, the Netherlands
| | - Stephan M Kraemer
- University of Vienna, Dept. of Environmental Geosciences, 1090, Vienna, Austria
| | - Janet G Hering
- Swiss Federal Institute of Technology (ETH) Zurich, IBP, CH-8092, Zürich, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland; Swiss Federal Institute of Technology Lausanne (EPFL), ENAC, CH-1015, Lausanne, Switzerland
| | - Stephan J Hug
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
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Rotterová J, Salomaki E, Pánek T, Bourland W, Žihala D, Táborský P, Edgcomb VP, Beinart RA, Kolísko M, Čepička I. Genomics of New Ciliate Lineages Provides Insight into the Evolution of Obligate Anaerobiosis. Curr Biol 2020; 30:2037-2050.e6. [PMID: 32330419 DOI: 10.1016/j.cub.2020.03.064] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/10/2020] [Accepted: 03/24/2020] [Indexed: 02/07/2023]
Abstract
Oxygen plays a crucial role in energetic metabolism of most eukaryotes. Yet adaptations to low-oxygen concentrations leading to anaerobiosis have independently arisen in many eukaryotic lineages, resulting in a broad spectrum of reduced and modified mitochondrion-related organelles (MROs). In this study, we present the discovery of two new class-level lineages of free-living marine anaerobic ciliates, Muranotrichea, cl. nov. and Parablepharismea, cl. nov., that, together with the class Armophorea, form a major clade of obligate anaerobes (APM ciliates) within the Spirotrichea, Armophorea, and Litostomatea (SAL) group. To deepen our understanding of the evolution of anaerobiosis in ciliates, we predicted the mitochondrial metabolism of cultured representatives from all three classes in the APM clade by using transcriptomic and metagenomic data and performed phylogenomic analyses to assess their evolutionary relationships. The predicted mitochondrial metabolism of representatives from the APM ciliates reveals functional adaptations of metabolic pathways that were present in their last common ancestor and likely led to the successful colonization and diversification of the group in various anoxic environments. Furthermore, we discuss the possible relationship of Parablepharismea to the uncultured deep-sea class Cariacotrichea on the basis of single-gene analyses. Like most anaerobic ciliates, all studied species of the APM clade host symbionts, which we propose to be a significant accelerating factor in the transitions to an obligately anaerobic lifestyle. Our results provide an insight into the evolutionary mechanisms of early transitions to anaerobiosis and shed light on fine-scale adaptations in MROs over a relatively short evolutionary time frame.
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Affiliation(s)
- Johana Rotterová
- Department of Zoology, Faculty of Science, Charles University, Prague 128 43, Czech Republic.
| | - Eric Salomaki
- Institute of Parasitology, Biology Centre Czech Academy of Sciences, České Budějovice 370 05, Czech Republic
| | - Tomáš Pánek
- Department of Zoology, Faculty of Science, Charles University, Prague 128 43, Czech Republic
| | - William Bourland
- Department of Biological Sciences, Boise State University, Boise, ID 83725-1515, USA
| | - David Žihala
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic
| | - Petr Táborský
- Institute of Parasitology, Biology Centre Czech Academy of Sciences, České Budějovice 370 05, Czech Republic
| | - Virginia P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Roxanne A Beinart
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - Martin Kolísko
- Institute of Parasitology, Biology Centre Czech Academy of Sciences, České Budějovice 370 05, Czech Republic; Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
| | - Ivan Čepička
- Department of Zoology, Faculty of Science, Charles University, Prague 128 43, Czech Republic
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Macek M, Medina XS, Picazo A, Peštová D, Reyes FB, Hernández JRM, Alcocer J, Ibarra MM, Camacho A. Spirostomum teres: A Long Term Study of an Anoxic-Hypolimnion Population Feeding upon Photosynthesizing Microorganisms. ACTA PROTOZOOL 2020. [DOI: 10.4467/16890027ap.20.002.12158] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pelagic / anoxic hypolimnion population of Spirostomum teres was investigated as a part of the long-term ciliates’ monitoring (2003–2016) in an oligo- to mesotrophic monomictic hyposaline crater lake Alchichica (Puebla / Veracruz, Mexico), including an analysis of picoplankton (both heterotrophic, HPP and autotrophic, APP) and inorganic compounds of nitrogen (ammonium, nitrite, nitrate), phosphorus (dissolved reactive phosphorus, DRP) and silicon. Additionally, detailed studies of the ciliate vertical distribution and feeding activity measured upon fluorescently labelled APP (picocyanobacteria) were carried out. The results were compared with those from a neighbour freshwater crater lake La Preciosa and with a meromictic karstic lake La Cruz (Cuenca, Spain). The ciliate vertical distribution within the water column was very well defined: During the first decade, the benthic population was frequently found throughout a developing stratification of the lake. The established stratification of the lake turned the conditions favourable for the formation of an oxycline / hypolimnion population, typically, several meters below the deep chlorophyll maximum (formed basically by diatoms); the population preferred the layers without detectable dissolved oxygen. However, an observed gradient of light (PAR) could support both oxygenic and anoxygenic photosynthesis. Late stratification after deepening of the thermocline reduced the layers with S. teres population to a minimum apparently due to the drastic change in physicochemical conditions within a metalimnion, coupled with an oxycline, and limited to 1 to 2 meters; microstratification was found. Last years, the very bottom population disappeared or it was reduced and the late stratification S. teres peaks were smaller or did not appeared. Generally, S. teres oxycline / anoxic hypolimnion population was observed from June through November. Optimum picoplankton numbers in conditions that supported the ciliate growth were found: The ciliate was peaking at APP of 0.6 to 1 × 105 cells mL–1; the optimum of HPP was observed round 1.4 × 106 cells mL–1. S. teres was efficiently feeding upon picocyanobacteria in numbers of 105 cells mL–1 reaching the clearance rate of 2000 nL cell–1h–1, which represented in average 130 to 210 cells cell–1h–1 ingested. Feeding upon purple sulphur bacteria was observed but only during the end of the lake stable stratification when the ciliate population was already dropping. On the other hand, the volume specific clearance of S. teres upon picocyanobacteria (103 h–1) did not support the hypothesis that they could serve as a sole prey. Feeding upon eukaryote phytoplankton (chlorophytes Monoraphidium minutum, diatoms Cyclotella choc tawhatcheeana) could be of higher importance that previously supposed. Additionally, a use of ingested and retained photosynthetic prokaryotes is hypothesized.
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Gavelis GS, Gile GH. How did cyanobacteria first embark on the path to becoming plastids?: lessons from protist symbioses. FEMS Microbiol Lett 2019; 365:5079637. [PMID: 30165400 DOI: 10.1093/femsle/fny209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/23/2018] [Indexed: 12/13/2022] Open
Abstract
Symbioses between phototrophs and heterotrophs (a.k.a 'photosymbioses') are extremely common, and range from loose and temporary associations to obligate and highly specialized forms. In the history of life, the most transformative was the 'primary endosymbiosis,' wherein a cyanobacterium was engulfed by a eukaryote and became genetically integrated as a heritable photosynthetic organelle, or plastid. By allowing the rise of algae and plants, this event dramatically altered the biosphere, but its remote origin over one billion years ago has obscured the sequence of events leading to its establishment. Here, we review the genetic, physiological and developmental hurdles involved in early primary endosymbiosis. Since we cannot travel back in time to witness these evolutionary junctures, we will draw on examples of unicellular eukaryotes (protists) spanning diverse modes of photosymbiosis. We also review experimental approaches that could be used to recreate aspects of early primary endosymbiosis on a human timescale.
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Affiliation(s)
- Gregory S Gavelis
- School of Life Sciences, Arizona State University, Room 611, Life Science Tower E, 427 E, Tyler Mall, Tempe, AZ 85287, USA
| | - Gillian H Gile
- School of Life Sciences, Arizona State University, Room 611, Life Science Tower E, 427 E, Tyler Mall, Tempe, AZ 85287, USA
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Nakajima T. Ecological extension of the theory of evolution by natural selection from a perspective of Western and Eastern holistic philosophy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 131:298-311. [DOI: 10.1016/j.pbiomolbio.2017.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/01/2017] [Accepted: 09/02/2017] [Indexed: 01/29/2023]
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Lanzoni O, Fokin SI, Lebedeva N, Migunova A, Petroni G, Potekhin A. Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium "Candidatus Holospora parva". PLoS One 2016; 11:e0167928. [PMID: 27992463 PMCID: PMC5161471 DOI: 10.1371/journal.pone.0167928] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/18/2016] [Indexed: 11/19/2022] Open
Abstract
Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of "green" ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name "Candidatus Holospora parva" for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.
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Affiliation(s)
| | - Sergei I. Fokin
- Department of Biology, University of Pisa, Pisa, Italy
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia
| | - Natalia Lebedeva
- Centre of Core Facilities “Culture Collections of Microorganisms”, Research Park, Saint Petersburg State University, Saint Petersburg, Russia
| | - Alexandra Migunova
- Department of Microbiology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia
| | | | - Alexey Potekhin
- Department of Microbiology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia
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12
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Pitsch G, Adamec L, Dirren S, Nitsche F, Šimek K, Sirová D, Posch T. The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant. J Eukaryot Microbiol 2016; 64:322-335. [PMID: 27613221 DOI: 10.1111/jeu.12369] [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: 07/12/2016] [Revised: 09/05/2016] [Accepted: 09/05/2016] [Indexed: 11/30/2022]
Abstract
The genus Tetrahymena (Ciliophora, Oligohymenophorea) probably represents the best studied ciliate genus. At present, more than forty species have been described. All are colorless, i.e. they do not harbor symbiotic algae, and as aerobes they need at least microaerobic habitats. Here, we present the morphological and molecular description of the first green representative, Tetrahymena utriculariae n. sp., living in symbiosis with endosymbiotic algae identified as Micractinium sp. (Chlorophyta). The full life cycle of the ciliate species is documented, including trophonts and theronts, conjugating cells, resting cysts and dividers. This species has been discovered in an exotic habitat, namely in traps of the carnivorous aquatic plant Utricularia reflexa (originating from Okavango Delta, Botswana). Green ciliates live as commensals of the plant in this anoxic habitat. Ciliates are bacterivorous, however, symbiosis with algae is needed to satisfy cell metabolism but also to gain oxygen from symbionts. When ciliates are cultivated outside their natural habitat under aerobic conditions and fed with saturating bacterial food, they gradually become aposymbiotic. Based on phylogenetic analyses of 18S rRNA and mitochondrial cox1 genes T. utriculariae forms a sister group to Tetrahymena thermophila.
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Affiliation(s)
- Gianna Pitsch
- Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland
| | - Lubomír Adamec
- Institute of Botany CAS, Section of Plant Ecology, Třeboň, 379 82, Czech Republic
| | - Sebastian Dirren
- Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland
| | - Frank Nitsche
- Institute for Zoology, General Ecology, Biocenter, University of Cologne, Cologne, 50674, Germany
| | - Karel Šimek
- Biology Centre CAS, Institute of Hydrobiology, České Budějovice, 370 05, Czech Republic
| | - Dagmara Sirová
- Biology Centre CAS, Institute of Hydrobiology, České Budějovice, 370 05, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Thomas Posch
- Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland
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Dean AD, Minter EJA, Sørensen MES, Lowe CD, Cameron DD, Brockhurst MA, Jamie Wood A. Host control and nutrient trading in a photosynthetic symbiosis. J Theor Biol 2016; 405:82-93. [PMID: 26925812 DOI: 10.1016/j.jtbi.2016.02.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 11/25/2022]
Abstract
Photosymbiosis is one of the most important evolutionary trajectories, resulting in the chloroplast and the subsequent development of all complex photosynthetic organisms. The ciliate Paramecium bursaria and the alga Chlorella have a well established and well studied light dependent endosymbiotic relationship. Despite its prominence, there remain many unanswered questions regarding the exact mechanisms of the photosymbiosis. Of particular interest is how a host maintains and manages its symbiont load in response to the allocation of nutrients between itself and its symbionts. Here we construct a detailed mathematical model, parameterised from the literature, that explicitly incorporates nutrient trading within a deterministic model of both partners. The model demonstrates how the symbiotic relationship can manifest as parasitism of the host by the symbionts, mutualism, wherein both partners benefit, or exploitation of the symbionts by the hosts. We show that the precise nature of the photosymbiosis is determined by both environmental conditions (how much light is available for photosynthesis) and the level of control a host has over its symbiont load. Our model provides a framework within which it is possible to pose detailed questions regarding the evolutionary behaviour of this important example of an established light dependent endosymbiosis; we focus on one question in particular, namely the evolution of host control, and show using an adaptive dynamics approach that a moderate level of host control may evolve provided the associated costs are not prohibitive.
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Affiliation(s)
- Andrew D Dean
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; Department of Mathematics, University of York, York YO10 5DD, UK.
| | - Ewan J A Minter
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Megan E S Sørensen
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Christopher D Lowe
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Treliever Road, Penryn TR10 9FE, UK
| | - Duncan D Cameron
- Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK
| | | | - A Jamie Wood
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; Department of Mathematics, University of York, York YO10 5DD, UK
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Origin, structure and function of millions of chromosomes present in the macronucleus of unicellular eukaryotic ciliate, Oxytricha trifallax: a model organism for transgenerationally programmed genome rearrangements. J Genet 2015; 94:171-6. [PMID: 26174664 DOI: 10.1007/s12041-015-0504-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Oikonomou A, Filker S, Breiner HW, Stoeck T. Protistan diversity in a permanently stratified meromictic lake (Lake Alatsee, SW Germany). Environ Microbiol 2014; 17:2144-57. [PMID: 25330396 DOI: 10.1111/1462-2920.12666] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/26/2014] [Accepted: 10/08/2014] [Indexed: 11/28/2022]
Abstract
Protists play a crucial role for ecosystem function(ing) and oxygen is one of the strongest barriers against their local dispersal. However, protistan diversity in freshwater habitats with oxygen gradients received very little attention. We applied high-throughput sequencing of the V9 region (18S rRNA gene) to provide a hitherto unique spatiotemporal analysis of protistan diversity along the oxygen gradient of a freshwater meromictic lake (Lake Alatsee, SW Germany). In the mixolimnion, the communities experienced most seasonal structural changes, with Stramenopiles dominating in autumn and Dinoflagellata in summer. The suboxic interface supported the highest diversity, but only 23 OTUs95% (mainly Euglenozoa, after quality check and removal of operational taxonomic units (OTUs) with less than three sequences) were exclusively associated with this habitat. Eukaryotic communities in the anoxic monimolimnion showed the most stable seasonal pattern, with Chrysophyta and Bicosoecida being the dominant taxa. Our data pinpoint to the ecological role of the interface as a short-term 'meeting point' for protists, contributing to the coupling of the mixolimnion and the monimolimnion. Our analyses of divergent genetic diversity suggest a high degree of previously undescribed OTUs. Future research will have to reveal if this result actually points to a high number of undescribed species in such freshwater habitats.
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Affiliation(s)
- Andreas Oikonomou
- Department of Ecology, University of Kaiserslautern, Erwin Schroedinger Str. 14, D-67663, Kaiserslautern, Germany
| | - Sabine Filker
- Department of Ecology, University of Kaiserslautern, Erwin Schroedinger Str. 14, D-67663, Kaiserslautern, Germany
| | - Hans-Werner Breiner
- Department of Ecology, University of Kaiserslautern, Erwin Schroedinger Str. 14, D-67663, Kaiserslautern, Germany
| | - Thorsten Stoeck
- Department of Ecology, University of Kaiserslautern, Erwin Schroedinger Str. 14, D-67663, Kaiserslautern, Germany
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16
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Sergeeva NG, Gooday AJ, Mazlumyan SA, Kolesnikova EA, Lichtschlag A, Kosheleva TN, Anikeeva OV. Meiobenthos of the Oxic/Anoxic Interface in the Southwestern Region of the Black Sea: Abundance and Taxonomic Composition. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2012. [DOI: 10.1007/978-94-007-1896-8_20] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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Saccà A. The Role of Eukaryotes in the Anaerobic Food Web of Stratified Lakes. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2012. [DOI: 10.1007/978-94-007-1896-8_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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18
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Meuser JE, Boyd ES, Ananyev G, Karns D, Radakovits R, Narayana Murthy UM, Ghirardi ML, Dismukes GC, Peters JW, Posewitz MC. Evolutionary significance of an algal gene encoding an [FeFe]-hydrogenase with F-domain homology and hydrogenase activity in Chlorella variabilis NC64A. PLANTA 2011; 234:829-43. [PMID: 21643991 DOI: 10.1007/s00425-011-1431-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 05/06/2011] [Indexed: 05/20/2023]
Abstract
[FeFe]-hydrogenases (HYDA) link the production of molecular H(2) to anaerobic metabolism in many green algae. Similar to Chlamydomonas reinhardtii, Chlorella variabilis NC64A (Trebouxiophyceae, Chlorophyta) exhibits [FeFe]-hydrogenase (HYDA) activity during anoxia. In contrast to C. reinhardtii and other chlorophycean algae, which contain hydrogenases with only the HYDA active site (H-cluster), C. variabilis NC64A is the only known green alga containing HYDA genes encoding accessory FeS cluster-binding domains (F-cluster). cDNA sequencing confirmed the presence of F-cluster HYDA1 mRNA transcripts, and identified deviations from the in silico splicing models. We show that HYDA activity in C. variabilis NC64A is coupled to anoxic photosynthetic electron transport (PSII linked, as well as PSII-independent) and dark fermentation. We also show that the in vivo H(2)-photoproduction activity observed is as O(2) sensitive as in C. reinhardtii. The two C. variabilis NC64A HYDA sequences are similar to homologs found in more deeply branching bacteria (Thermotogales), diatoms, and heterotrophic flagellates, suggesting that an F-cluster HYDA is the ancestral enzyme in algae. Phylogenetic analysis indicates that the algal HYDA H-cluster domains are monophyletic, suggesting that they share a common origin, and evolved from a single ancestral F-cluster HYDA. Furthermore, phylogenetic reconstruction indicates that the multiple algal HYDA paralogs are the result of gene duplication events that occurred independently within each algal lineage. Collectively, comparative genomic, physiological, and phylogenetic analyses of the C. variabilis NC64A hydrogenase has provided new insights into the molecular evolution and diversity of algal [FeFe]-hydrogenases.
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Affiliation(s)
- Jonathan E Meuser
- Division of Environmental Science and Engineering, Colorado School of Mines, Golden, CO 80401, USA
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Beaudoin DJ, Bernhard JM, Edgcomb VP. A Novel Ciliate (Ciliophora: Hypotrichida) Isolated from Bathyal Anoxic Sediments. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-94-007-1896-8_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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20
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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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21
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Ciliates in chalk-stream habitats congregate in biodiversity hot spots. Res Microbiol 2010; 161:619-25. [DOI: 10.1016/j.resmic.2010.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/19/2010] [Accepted: 05/25/2010] [Indexed: 11/22/2022]
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Auto-/heterotrophic endosymbiosis evolves in a mature stage of ecosystem development in a microcosm composed of an alga, a bacterium and a ciliate. Biosystems 2009; 96:127-35. [DOI: 10.1016/j.biosystems.2008.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 12/18/2008] [Accepted: 12/22/2008] [Indexed: 11/19/2022]
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23
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Esteban GF, Finlay BJ, Clarke KJ. Sequestered organelles sustain aerobic microbial life in anoxic environments. Environ Microbiol 2009; 11:544-50. [PMID: 19196284 DOI: 10.1111/j.1462-2920.2008.01797.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report aerobic eukaryotic microbial life in the dimly lit anoxic water layer of a small freshwater lake. The microbial eukaryote is the ciliated protozoon Histiobalantium natans. Electron microscopy of thin sections shows that the cytoplasm of the ciliate harbours sequestered chloroplasts and sequestered mitochondria. The sequestered chloroplasts are attached or in very close proximity to the ciliate's own mitochondria. The sequestered mitochondria also seem to be associated with host-ciliate mitochondria. We suggest that the oxygenic photosynthetic activity of sequestered chloroplasts, perhaps enhanced by respiration in sequestered mitochondria, contributes to servicing the respiratory oxygen requirements of the ciliate host in its anoxic habitat. Our observations are novel, with the discovery of an aerobic microbial eukaryote capable of thriving and completing its life cycle in an anoxic environment, fuelled by oxygen generated by sequestered chloroplasts. The acknowledged flexibility and functional diversity within eukaryotic microbial communities still have many secrets to release.
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Affiliation(s)
- Genoveva F Esteban
- Queen Mary University of London, School of Biological and Chemical Sciences, The River Laboratory, Wareham, Dorset, UK.
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Photobiological Aspects of the Mutualistic Association Between Paramecium bursaria and Chlorella. ENDOSYMBIONTS IN PARAMECIUM 2009. [DOI: 10.1007/978-3-540-92677-1_5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Abstract
Oxygen has two faces. On one side it is the terminal electron acceptor of aerobic respiration - the most efficient engine of energy metabolism. On the other hand, oxygen is toxic because the reduction of molecular O2 creates reactive oxygen species such as the superoxide anion, peroxide, and the hydroxyl radical. Probably most prokaryotes, and virtually all eukaryotes, depend on oxygen respiration, and we show that the ambiguous relation to oxygen is both an evolutionary force and a dominating factor driving functional interactions and the spatial structure of microbial communities.We focus on microbial communities that are specialised for life in concentration gradients of oxygen, where they acquire the full panoply of specific requirements from limited ranges of PO2, which also support the spatial organisation of microbial communities. Marine and lake sediments provide examples of steep O2 gradients, which arise because consumption or production of oxygen exceeds transport rates of molecular diffusion. Deep lakes undergo thermal stratification in warm waters, resulting in seasonal anaerobiosis below the thermocline, and lakes with a permanent pycnocline often have permanent anoxic deep water. The oxycline is here biologically similar to sediments, and it harbours similar microbial biota, the main difference being the spatial scale. In sediments, transport is dominated by molecular diffusion, and in the water column, turbulent mixing dominates vertical transport. Cell size determines the minimum requirement of aerobic organisms. For bacteria (and mitochondria), the half-saturation constant for oxygen uptake ranges within 0.05-0.1% atmospheric saturation; for the amoeba Acanthamoeba castellanii it is 0.2%, and for two ciliate species measuring around 150 microm, it is 1-2 % atmospheric saturation. Protection against O2 toxicity has an energetic cost that increases with increasing ambient O2 tension. Oxygen sensing seems universal in aquatic organisms. Many aspects of oxygen sensing are incompletely understood, but the mechanisms seem to be evolutionarily conserved. A simple method of studying oxygen preference in microbes is to identify the preferred oxygen tension accumulating in O2 gradients. Microorganisms cannot sense the direction of a chemical gradient directly, so they use other devices to orient themselves. Different mechanisms in different prokaryotic and eukaryotic microbes are described. In O2 gradients, many bacteria and protozoa are vertically distributed according to oxygen tension and they show a very limited range of preferred PO2. In some pigmented protists the required PO2 is contingent on light due to photochemically generated reactive oxygen species. In protists that harbour endosymbiotic phototrophs, orientation towards light is mediated through the oxygen production of their photosynthetic symbionts. Oxygen plays a similar role for the distribution of small metazoans (meiofauna) in sediments, but there is little experimental evidence for this. Thus the oxygenated sediments surrounding ventilated animal burrows provide a special habitat for metazoan meiofauna as well as unicellular organisms.
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Affiliation(s)
- Tom Fenchel
- Marine Biological Laboratory, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark.
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Pestová D, Macek M, Elena Martínez Pérez M. Ciliates and their picophytoplankton-feeding activity in a high-altitude warm-monomictic saline lake. Eur J Protistol 2007; 44:13-25. [PMID: 17931843 DOI: 10.1016/j.ejop.2007.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 04/19/2007] [Accepted: 04/23/2007] [Indexed: 10/22/2022]
Abstract
The impact of feeding on autotrophic picoplankton (APP) on the ciliate composition of the assemblage was surveyed monthly along a depth gradient in the maar crater, athalassohaline, warm monomictic Lake Alchichica (Puebla, Mexico) from June 2003 to December 2005. Numbers of APP were evaluated from their autofluorescence. DAPI staining and the Fluorescently Labeled Bacteria technique were employed to count ciliates and estimate their feeding rates. A total of 38 taxa of ciliates have been identified using Quantitative Protargol Staining. Peritrichs followed by minute spirotrichs (particularly Halteria grandinella) often numerically dominated the ciliate assemblage and emerged as the most efficient APP feeders. A maximum of 54 ciliate cells ml(-1) was observed in the surface layer at the end of the mixing period, during the development of diatoms (Cyclotella alchichicana), the cyanobacterial bloom (Nodularia sp.) and its decay. Vorticellids (Pelagovorticella natans, Vorticella sp.) had the highest APP uptake (median 130 APP cil(-1) h(-1)). Mixotrophic Euplotes cf. daidaleos were important APP grazers near the oxycline. Scuticociliates (Cyclidium glaucoma, Uronema nigricans and an anaerobic cf. Isocyclidium globossum), were numerically dominant within the hypolimnetic assemblages and did not ingest APP. Generally, APP were not an important food source for the majority of the ciliate assemblage, being positively selected by a few species during the APP decay in aerobic and microaerobic conditions.
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Affiliation(s)
- Dana Pestová
- Universidad Nacional Autónoma de México campus Iztacala, Av. de los Barrios 1, los Reyes Iztacala, Tlalnepantla, 54090 Edo. Mexico, Mexico.
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Hackstein JHP, Yarlett N. Hydrogenosomes and symbiosis. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2005; 41:117-42. [PMID: 16623392 DOI: 10.1007/3-540-28221-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Johannes H P Hackstein
- Department of Evolutionary Microbiology, Faculty of Science, Radboud University Nijmegen, Toernooiveld 1, NL 6525 ED Nijmegen, The Netherlands.
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Abstract
This is an exploration of contemporary protist taxonomy within an ecological perspective. As it currently stands, the 'morphospecies' does not accommodate the information that might support a truly ecological species concept for the protists. But the 'morphospecies' is merely a first step in erecting a taxonomy of the protists, and it is expected to become more meaningful in the light of genetic, physiological and ecological research in the near future. One possible way forward lies in the recognition that sexual and asexual protists may all be subject to forces of cohesion that result in (DNA) sequence-similarity clusters. A starting point would then be the detection of 'ecotypes'--where genotypic and phenotypic clusters correspond; but for that we need better information regarding the extent of clonality in protists, and better characterization of ecological niches and their boundaries. There is some progress with respect to the latter. Using the example of a community of ciliated protozoa living in the stratified water column of a freshwater pond, it is shown to be possible to gauge the potential of protists to partition their local environment into ecological niches. Around 40 morphospecies can coexist in the superimposed water layers, which presumably represent different ecological niches, but we have yet to discover if these are discrete or continuously variable. It is a myth that taxonomic problems are more severe for protists than for animals and plants. Most of the fundamental problems associated with species concepts (e.g. asexuals, sibling species, phenotypic variation) are distributed across biota in general. The recent history of the status of Pfiesteria provides a model example of an integrated approach to solving what are essentially taxonomic problems.
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Affiliation(s)
- Bland J Finlay
- CEH Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester DT2 8ZD, UK.
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29
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Hackstein JHP, Van Hoek AHAM, Leunissen JAM, Huynen M. Anaerobic Ciliates and Their Metahanogenic Endosymbionts. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2001. [DOI: 10.1007/0-306-48173-1_28] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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30
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Abstract
Evidence is presented for the ubiquity of protist species. Using the example of protists that leave traces (siliceous scales) of their recent population growth, we show that most - perhaps all species in the genus Paraphysomonas, are ubiquitous. Of the species recorded in surveys carried out worldwide, we have identified 78% of their number in 0.1 cm2 of sediment collected from a freshwater pond (total area 10(8) cm2) in England. Moreover, the pond appears to act like a microcosm of aquatic environments in general, for species that are globally rare or abundant, are likewise rare or abundant in the pond. We assume that the rate of neutral migration to the pond is greatest for the globally abundant species. As these species are probably capable of growth in a broad range of conditions, they will more frequently encounter the environment they require for population growth. Thus globally abundant species are also locally abundant in the pond - a pattern that will be amplified by periodic cyst production. Ubiquitous dispersal is probably driven by very high absolute abundance of individuals, and the water column of the pond was estimated to support >10(14) Paraphysomonas individuals. Ubiquity will dampen rates of speciation, and the evidence presented here indicates that global species richness of Paraphysomonas is indeed modest - perhaps close to what is already known.
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Affiliation(s)
- B J Finlay
- Institute of Freshwater Ecology, Windermere Laboratory, The Ferry House, Ambleside, Cumbria, UK.
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31
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Finlay BJ, Esteban GF. Planktonic Ciliate Species Diversity as an Integral Component of Ecosystem Function in a Freshwater Pond. Protist 1998. [DOI: 10.1016/s1434-4610(98)70020-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
It is widely believed that the number of species of micro-organisms in the world is extremely large. Here, we offer the contrasting view--that the number may be quite modest. Most of the work reviewed refers to the ciliated protozoa. As with all microbial groups, we must define our concept of "species", and for ciliates, the "morphospecies" concept appears to be at least as robust as any other. Critical examination of published descriptions of ciliates provides a "best estimate" of 3744 for the global number of free-living morphospecies. Of these, 793 are associated with marine sediments, and 1370 with freshwater sediments. In an independent analysis based on extrapolation (assuming the ubiquity of species) from ecological datasets, we estimate the numbers of species in marine and freshwater sediments as 597 and 732, respectively (i.e. within a factor of two of the figures obtained from taxonomic analysis). This apparent convergence of independent estimates will strengthen if, as is likely, the number of nominal species is further reduced by taxonomic revision. These relatively low numbers of species are consistent with (a) the vast amount of published information indicating typically cosmopolitan distributions for ciliates and other microbes, and (b) recent experimental evidence that most free-living ciliates are rare or cryptic--seldom detectable, but present, and "waiting" for suitable conditions to arrive. In summary, most ciliates (and other micro-organisms) are probably ubiquitous, endemics are rare, global species richness is relatively low, and, at least in the case of the ciliates, most species have already been discovered.
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Affiliation(s)
- B J Finlay
- Institute of Freshwater Ecology, Ambleside, Cumbria, UK.
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Esteban GF, Finlay BJ. Morphology and Ecology of the Cosmopolitan Ciliate Prorodon viridis. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0003-9365(96)80032-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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