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Yarlett N, Jarroll EL, Morada M, Lloyd D. Protists: Eukaryotic single-celled organisms and the functioning of their organelles. Adv Microb Physiol 2024; 84:243-307. [PMID: 38821633 DOI: 10.1016/bs.ampbs.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Organelles are membrane bound structures that compartmentalize biochemical and molecular functions. With improved molecular, biochemical and microscopy tools the diversity and function of protistan organelles has increased in recent years, providing a complex panoply of structure/function relationships. This is particularly noticeable with the description of hydrogenosomes, and the diverse array of structures that followed, having hybrid hydrogenosome/mitochondria attributes. These diverse organelles have lost the major, at one time, definitive components of the mitochondrion (tricarboxylic cycle enzymes and cytochromes), however they all contain the machinery for the assembly of Fe-S clusters, which is the single unifying feature they share. The plasticity of organelles, like the mitochondrion, is therefore evident from its ability to lose its identity as an aerobic energy generating powerhouse while retaining key ancestral functions common to both aerobes and anaerobes. It is interesting to note that the apicoplast, a non-photosynthetic plastid that is present in all apicomplexan protozoa, apart from Cryptosporidium and possibly the gregarines, is also the site of Fe-S cluster assembly proteins. It turns out that in Cryptosporidium proteins involved in Fe-S cluster biosynthesis are localized in the mitochondrial remnant organelle termed the mitosome. Hence, different organisms have solved the same problem of packaging a life-requiring set of reactions in different ways, using different ancestral organelles, discarding what is not needed and keeping what is essential. Don't judge an organelle by its cover, more by the things it does, and always be prepared for surprises.
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Affiliation(s)
- Nigel Yarlett
- Haskins Laboratories, Pace University, New York, NY, United States; The Department of Chemistry and Physical Sciences, Pace University, New York, NY, United States.
| | - Edward L Jarroll
- Department of Biological Sciences, CUNY-Lehman College, Bronx, NY, United States
| | - Mary Morada
- Haskins Laboratories, Pace University, New York, NY, United States
| | - David Lloyd
- Schools of Biosciences and Engineering, Cardiff University, Wales, United Kingdom
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2
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The Genome of the Mitochondrion-Related Organelle in Cepedea longa, a Large Endosymbiotic Opalinid Inhabiting the Recta of Frogs. Int J Mol Sci 2022; 23:ijms232113472. [DOI: 10.3390/ijms232113472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/13/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
Mitochondrion-related organelles (MROs) are loosely defined as degenerated mitochondria in anaerobic and microaerophilic lineages. Opalinids are commonly regarded as commensals in the guts of cold-blooded amphibians. It may represent an intermediate adaptation stage between the conventional aerobic mitochondria and derived anaerobic MROs. In the present study, we sequenced and analyzed the MRO genome of Cepedea longa. It has a linear MRO genome with large inverted repeat gene regions at both ends. Compared to Blastocystis and Proteromonas lacertae, the MRO genome of C. longa has a higher G + C content and repeat sequences near the central region. Although three Opalinata species have different morphological characteristics, phylogenetic analyses based on eight concatenated nad genes indicate that they are close relatives. The phylogenetic analysis showed that C. longa clustered with P. lacertae with strong support. The 18S rRNA gene-based phylogeny resolved the Opalinea clade as a sister clade to Karotomorpha, which then further grouped with Proteromonas. The paraphyly of Proteromonadea needs to be verified due to the lack of MRO genomes for key species, such as Karotomorpha, Opalina and Protoopalina. Besides, our dataset and analyses offered slight support for the paraphyly of Bigyra.
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Fenchel T. Bland James Finlay (March 16, 1952-December 24, 2021). Protist 2022; 173:125906. [PMID: 36041339 DOI: 10.1016/j.protis.2022.125906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Tom Fenchel
- Marine Biological Laboratory, University of Copenhagen, DK-3000 Helsingør, Denmark.
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Oxygen levels are key to understanding "Anaerobic" protozoan pathogens with micro-aerophilic lifestyles. Adv Microb Physiol 2021; 79:163-240. [PMID: 34836611 DOI: 10.1016/bs.ampbs.2021.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Publications abound on the physiology, biochemistry and molecular biology of "anaerobic" protozoal parasites as usually grown under "anaerobic" culture conditions. The media routinely used are poised at low redox potentials using techniques that remove O2 to "undetectable" levels in sealed containers. However there is growing understanding that these culture conditions do not faithfully resemble the O2 environments these organisms inhabit. Here we review for protists lacking oxidative energy metabolism, the oxygen cascade from atmospheric to intracellular concentrations and relevant methods of measurements of O2, some well-studied parasitic or symbiotic protozoan lifestyles, their homeodynamic metabolic and redox balances, organism-drug-oxygen interactions, and the present and future prospects for improved drugs and treatment regimes.
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Bourland W, Rotterová J, Čepička I. Description of Three New Genera of Metopidae (Metopida, Ciliophora): Pileometopus gen. nov., Castula gen. nov., and Longitaenia gen. nov., with Notes on the Phylogeny and Cryptic Diversity of Metopid Ciliates. Protist 2020; 171:125740. [PMID: 32544844 DOI: 10.1016/j.protis.2020.125740] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/19/2020] [Accepted: 04/29/2020] [Indexed: 01/22/2023]
Abstract
We report the discovery of three new species of freshwater metopid ciliates, Pileometopus lynni gen. et sp. nov., Castula flexibilis gen. et sp. nov., and Longitaenia australis gen. et sp. nov. Based on morphologic features and the 18S rRNA gene phylogeny, we transfer two known species of Metopus to the new genus Castula, as C. fusca (Kahl, 1927) comb. nov. and C. setosa (Kahl, 1927) comb. nov. and another known species is herein transferred to the new genus Longitaenia, as L. gibba (Kahl, 1927) comb. nov. Pileometopus is characterized by a turbinate body shape, a dorsal field of densely spaced dikinetids, a bipartite paroral membrane, and long caudal cilia. A distinctive morphologic feature of Castula species is long setae arising over the posterior third of the body (as opposed to a terminal tuft). Longitaenia spp. are characterized by an equatorial cytostome and long perizonal ciliary stripe relative to the cell length. Based on phylogenetic analyses of 18S rRNA gene sequences, we identify and briefly discuss strongly supported clades and intraspecific genetic polymorphism within the order Metopida.
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Affiliation(s)
- William Bourland
- Boise State University, Department of Biological Sciences, Boise, Idaho 83725-1515, USA.
| | - Johana Rotterová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Ivan Čepička
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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Zhao W, Li M, Xiong F, Zhang D, Wu S, Zou H, Li W, Wang G. Identification of Intracellular Bacteria in the Ciliate
Balantidium ctenopharyngodoni
(Ciliophora, Litostomatea). J Eukaryot Microbiol 2020; 67:417-426. [DOI: 10.1111/jeu.12791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/09/2020] [Accepted: 02/06/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Weishan Zhao
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Ming Li
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
| | - Fan Xiong
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
| | - Dong Zhang
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Shangong Wu
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
| | - Hong Zou
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
| | - Wenxiang Li
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
| | - Guitang Wang
- Key Laboratory of Aquaculture Disease Control Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China
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Lloyd D, Millet CO, Williams CF, Hayes AJ, Pope SJA, Pope I, Borri P, Langbein W, Olsen LF, Isaacs MD, Lunding A. Functional imaging of a model unicell: Spironucleus vortens as an anaerobic but aerotolerant flagellated protist. Adv Microb Physiol 2020; 76:41-79. [PMID: 32408947 DOI: 10.1016/bs.ampbs.2020.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Advances in optical microscopy are continually narrowing the chasm in our appreciation of biological organization between the molecular and cellular levels, but many practical problems are still limiting. Observation is always limited by the rapid dynamics of ultrastructural modifications of intracellular components, and often by cell motility: imaging of the unicellular protist parasite of ornamental fish, Spironucleus vortens, has proved challenging. Autofluorescence of nicotinamide nucleotides and flavins in the 400-580 nm region of the visible spectrum, is the most useful indicator of cellular redox state and hence vitality. Fluorophores emitting in the red or near-infrared (i.e., phosphors) are less damaging and more penetrative than many routinely employed fluors. Mountants containing free radical scavengers minimize fluorophore photobleaching. Two-photon excitation provides a small focal spot, increased penetration, minimizes photon scattering and enables extended observations. Use of quantum dots clarifies the competition between endosomal uptake and exosomal extrusion. Rapid motility (161 μm/s) of the organism makes high resolution of ultrastructure difficult even at high scan speeds. Use of voltage-sensitive dyes determining transmembrane potentials of plasma membrane and hydrogenosomes (modified mitochondria) is also hindered by intracellular motion and controlled anesthesia perturbs membrane organization. Specificity of luminophore binding is always questionable; e.g. cationic lipophilic species widely used to measure membrane potentials also enter membrane-bounded neutral lipid droplet-filled organelles. This appears to be the case in S. vortens, where Coherent Anti-Stokes Raman Scattering (CARS) micro-spectroscopy unequivocally images the latter and simultaneous provides spectral identification at 2840 cm-1. Secondary Harmonic Generation highlights the highly ordered structure of the flagella.
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Affiliation(s)
- David Lloyd
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom; School of Engineering, Cardiff, Wales, United Kingdom
| | - Coralie O Millet
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | | | - Anthony J Hayes
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Simon J A Pope
- School of Chemistry, Main Building, Cardiff University, Cardiff, Wales, United Kingdom
| | - Iestyn Pope
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Paola Borri
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Wolfgang Langbein
- School of Physics and Astronomy, Cardiff University, Cardiff, Wales, United Kingdom
| | - Lars Folke Olsen
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Marc D Isaacs
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Anita Lunding
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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8
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Hackstein JHP, de Graaf RM, van Hellemond JJ, Tielens AGM. Hydrogenosomes of Anaerobic Ciliates. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-3-030-17941-0_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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9
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Garajová M, Mrva M, Vaškovicová N, Martinka M, Melicherová J, Valigurová A. Cellulose fibrils formation and organisation of cytoskeleton during encystment are essential for Acanthamoeba cyst wall architecture. Sci Rep 2019; 9:4466. [PMID: 30872791 PMCID: PMC6418277 DOI: 10.1038/s41598-019-41084-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 03/01/2019] [Indexed: 01/26/2023] Open
Abstract
Acanthamoebae success as human pathogens is largely due to the highly resistant cysts which represent a crucial problem in treatment of Acanthamoeba infections. Hence, the study of cyst wall composition and encystment play an important role in finding new therapeutic strategies. For the first time, we detected high activity of cytoskeletal elements - microtubular networks and filamentous actin, in late phases of encystment. Cellulose fibrils - the main components of endocyst were demonstrated in inter-cystic space, and finally in the ectocyst, hereby proving the presence of cellulose in both layers of the cyst wall. We detected clustering of intramembranous particles (IMPs) and their density alterations in cytoplasmic membrane during encystment. We propose a hypothesis that in the phase of endocyst formation, the IMP clusters represent cellulose microfibril terminal complexes involved in cellulose synthesis that after cyst wall completion are reduced. Cyst wall impermeability, due largely to a complex polysaccharide (glycans, mainly cellulose) has been shown to be responsible for Acanthamoeba biocide resistance and cellulose biosynthesis pathway is suggested to be a potential target in treatment of Acanthamoeba infections. Disruption of this pathway would affect the synthesis of cyst wall and reduce considerably the resistance to chemotherapeutic agents.
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Affiliation(s)
- Mária Garajová
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic.
| | - Martin Mrva
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Naděžda Vaškovicová
- Institute of Scientific Instruments, Czech Academy of Sciences, 612 64, Brno, Czech Republic
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Janka Melicherová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
| | - Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
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10
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Taylor GT. Windows into Microbial Seascapes: Advances in Nanoscale Imaging and Application to Marine Sciences. ANNUAL REVIEW OF MARINE SCIENCE 2019; 11:465-490. [PMID: 30134123 DOI: 10.1146/annurev-marine-121916-063612] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Geochemical cycles of all nonconservative elements are mediated by microorganisms over nanometer spatial scales. The pelagic seascape is known to possess microstructure imposed by heterogeneous distributions of particles, polymeric gels, biologically important chemicals, and microbes. While indispensable, most traditional oceanographic observational approaches overlook this heterogeneity and ignore subtleties, such as activity hot spots, symbioses, niche partitioning, and intrapopulation phenotypic variations, that can provide a deeper mechanistic understanding of planktonic ecosystem function. As part of the movement toward cultivation-independent tools in microbial oceanography, techniques to examine the ecophysiology of individual populations and their role in chemical transformations at spatial scales relevant to microorganisms have been developed. This review presents technologies that enable geochemical and microbiological interrogations at spatial scales ranging from 0.02 to a few hundred micrometers, particularly focusing on atomic force microscopy, nanoscale secondary ion mass spectrometry, and confocal Raman microspectroscopy and introducing promising approaches for future applications in marine sciences.
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Affiliation(s)
- Gordon T Taylor
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, USA;
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11
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Vďačný P, Érseková E, Šoltys K, Budiš J, Pecina L, Rurik I. Co-existence of multiple bacterivorous clevelandellid ciliate species in hindgut of wood-feeding cockroaches in light of their prokaryotic consortium. Sci Rep 2018; 8:17749. [PMID: 30532066 PMCID: PMC6288088 DOI: 10.1038/s41598-018-36245-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 11/15/2018] [Indexed: 11/23/2022] Open
Abstract
The hindgut of wood-feeding Panesthia cockroaches harbours a diverse microbial community, whose most morphologically prominent members are bacterivorous clevelandellid ciliates. Co-occurrence and correlation patterns of prokaryotes associated with these endosymbiotic ciliates were investigated. Multidimensional scaling based on taxa interaction-adjusted index showed a very clear separation of the hindgut ciliate samples from the ciliate-free hindgut samples. This division was corroborated also by SparCC analysis which revealed strong negative associations between prokaryotic taxa that were relatively more abundant in the ciliate-free hindgut samples and prokaryotic taxa that were more abundant in the ciliate samples. This very likely reflects the grazing behaviour of hindgut ciliates which prefer Proteobacteria, Firmicutes and Actinobacteria, causing their abundances to be increased in the ciliate samples at the expense of abundances of Euryarchaeota and Bacteroidetes which prevail in the hindgut content. Ciliate species do not distinctly differ in the associated prokaryotes, indicating that minute variations in the proportion of associated bacteria might be sufficient to avoid competition between bacterivorous ciliate species and hence enable their co-occurrence in the same host. The nearest free-living relatives of hindgut ciliates have a different pattern of associations with prokaryotes, i.e., alphaproteobacteria are predominantly associated with free-living ciliates while gammaproteobacteria with hindgut ciliates.
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Affiliation(s)
- Peter Vďačný
- Department of Zoology, Comenius University in Bratislava, 842 15, Bratislava, Slovakia.
| | - Emese Érseková
- Department of Zoology, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Katarína Šoltys
- Comenius University Science Park, Comenius University in Bratislava, 841 04, Bratislava, Slovakia
| | - Jaroslav Budiš
- Department of Computer Science, Comenius University in Bratislava, Mlynská dolina F-1, 842 48, Bratislava, Slovakia
| | - Lukáš Pecina
- Department of Zoology, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Ivan Rurik
- Private computer laboratory, 821 07, Bratislava, Slovakia
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Tropidoatractidae fam. nov., a Deep Branching Lineage of Metopida (Armophorea, Ciliophora) Found in Diverse Habitats and Possessing Prokaryotic Symbionts. Protist 2018; 169:362-405. [DOI: 10.1016/j.protis.2018.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 11/29/2022]
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13
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Morphologic and molecular characterization of seven species of the remarkably diverse and widely distributed metopid genus Urostomides Jankowski, 1964 (Armophorea, Ciliophora). Eur J Protistol 2017; 61:194-232. [DOI: 10.1016/j.ejop.2017.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/06/2017] [Accepted: 07/13/2017] [Indexed: 11/17/2022]
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14
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Omar A, Zhang Q, Zou S, Gong J. Morphology and Phylogeny of the Soil Ciliate Metopus yantaiensis
n. sp. (Ciliophora, Metopida), with Identification of the Intracellular Bacteria. J Eukaryot Microbiol 2017; 64:792-805. [DOI: 10.1111/jeu.12411] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/02/2017] [Accepted: 03/08/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Atef Omar
- Laboratory of Microbial Ecology and Matter Cycles; Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences; Yantai 264003 China
- Department of Zoology; Al-Azhar University; Assiut 71524 Egypt
| | - Qianqian Zhang
- Laboratory of Microbial Ecology and Matter Cycles; Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences; Yantai 264003 China
| | - Songbao Zou
- Laboratory of Microbial Ecology and Matter Cycles; Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences; Yantai 264003 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Jun Gong
- Laboratory of Microbial Ecology and Matter Cycles; Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences; Yantai 264003 China
- University of Chinese Academy of Sciences; Beijing 100049 China
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15
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Millet COM, Williams CF, Hayes AJ, Hann AC, Cable J, Lloyd D. Mitochondria-derived organelles in the diplomonad fish parasite Spironucleus vortens. Exp Parasitol 2013; 135:262-73. [PMID: 23867147 DOI: 10.1016/j.exppara.2013.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/02/2013] [Accepted: 07/03/2013] [Indexed: 11/15/2022]
Abstract
In some eukaryotes, mitochondria have become modified during evolution to yield derived organelles (MDOs) of a similar size (hydrogenosomes), or extremely reduced to produce tiny cellular vesicles (mitosomes). The current study provides evidence for the presence of MDOs in the highly infectious fish pathogen Spironucleus vortens, an organism that produces H₂ and is shown here to have no detectable cytochromes. Transmission electron microscopy (TEM) reveals that S. vortens trophozoites contain electron-dense, membranous structures sometimes with an electron-dense core (200 nm-1 μm), resembling the hydrogenosomes previously described in other protists from habitats deficient in O₂. Confocal microscopy establishes that these organelles exhibit autofluorescence emission spectra similar to flavoprotein constituents previously described for mitochondria and also present in hydrogenosomes. These organelles possess a membrane potential and are labelled by a fluorescently labeled antibody against Fe-hydrogenase from Blastocystis hominis. Heterologous antibodies raised to mitochondrial proteins frataxin and Isu1, also exhibit a discrete punctate pattern of localization in S. vortens; however these labelled structures are distinctly smaller (90-150 nm) than hydrogenosomes as observed previously in other organisms. TEM confirms the presence of double-membrane bounded organelles of this smaller size. In addition, strong background immunostaining occurs in the cytosol for frataxin and Isu1, and labelling by anti-ferredoxin antibody is generally distributed and not specifically localized except for at the anterior polar region. This suggests that some of the functions traditionally attributed to such MDOs may also occur elsewhere. The specialized parasitic life-style of S. vortens may necessitate more complex intracellular compartmentation of redox reactions than previously recognized. Control of infection requires biochemical characterization of redox-related organelles.
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16
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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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17
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18
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Narayanan N, Krishnakumar B, Anupama VN, Manilal VB. Methanosaeta sp., the major archaeal endosymbiont of Metopus es. Res Microbiol 2009; 160:600-7. [PMID: 19695326 DOI: 10.1016/j.resmic.2009.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/17/2009] [Accepted: 07/24/2009] [Indexed: 10/20/2022]
Abstract
Epifluorescence microscopy and whole cell in situ hybridization analysis revealed the presence of Methanosaeta sp. as endosymbionts in Metopus es. Direct microscopic observation under epifluorescent microscope showed the presence of long slender rods with an average length of 3.4 microm. The number of methanogenic rods varied from 792 +/- 12 in a single M. es cell with a biovolume of 3.4 x 10(5) microm(3). At the exponential growth stage, a single symbiotic methanogen in M. es produced about 1 fmol methane/h leading to a methane production rate of 0.85 pmol/ciliate/h. The presence of endosymbiotic methanogens in the domain archaea and Methanosaeta sp. was confirmed by FISH with ARCH 915 and MX 825 oligonucleotide probes specific to domain archaea and Methanosaeta respectively. The homogenized cells of M. es also showed bright fluorescing rods with MX 825 hybridization. The culture obtained on inoculation of the released endosymbiotic organisms on Methanosaeta-specific medium lent support to the growth of long slender rods having the same range of mean length (3.6 microm) as that of the endosymbiotic methanogens observed. Both intra- and extracellular production of acetate was detected in M. es culture.
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Affiliation(s)
- Nimi Narayanan
- Process Engineering and Environmental Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Thiruvananthapuram, 695019 Kerala, India.
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19
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Benchimol M. Hydrogenosomes under microscopy. Tissue Cell 2009; 41:151-68. [PMID: 19297000 DOI: 10.1016/j.tice.2009.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Revised: 01/04/2009] [Accepted: 01/13/2009] [Indexed: 11/19/2022]
Abstract
A hydrogenosome is a hydrogen-producing organelle, evolutionary related to mitochondria and is found in Parabasalia protozoa, certain chytrid fungi and certain ciliates. It displays similarities to and differences from mitochondria. Hydrogenosomes are spherical or slightly elongated organelles, although very elongated hydrogenosomes are also found. They measure from 200 nm to 1 microm, but under stress conditions can reach up to 2 microm. Hydrogenosomes are surrounded by two closely apposed membranes and present a granular matrix. Cardiolipin has been detected in their membranes, and frataxin, which is a conserved mitochondrial protein involved in iron metabolism, was also recently found. Hydrogenosomes have one or multiple peripheral vesicles, which incorporate calcium. The peripheral vesicle can be isolated from the hydrogenosomal matrix and can be considered as a distinct hydrogenosomal compartment. Dysfunctional hydrogenosomes can be removed by an autophagic process and further digested by lysosomes. Hydrogenosomes divide in three different ways, like mitochondria, by segmentation, partition and the heart form. They may divide at any phase of the cell cycle. Nucleoid or electron dense deposits found in hydrogenosomes can be considered artifacts or dysfunctional hydrogenosomes. The hydrogenosome does not contain a genome, although DNA has already been detected in one anaerobic ciliate. Hydrogenosomes can be considered as good drug targets since their metabolism is distinct from mitochondria.
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Affiliation(s)
- Marlene Benchimol
- Universidade Santa Ursula, Laboratório de Ultraestrutura Celular, Rio de Janeiro, Brazil.
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Hydrogenosomes of Anaerobic Ciliates. HYDROGENOSOMES AND MITOSOMES: MITOCHONDRIA OF ANAEROBIC EUKARYOTES 2008. [DOI: 10.1007/7171_2007_109] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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21
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Takishita K, Tsuchiya M, Kawato M, Oguri K, Kitazato H, Maruyama T. Genetic Diversity of Microbial Eukaryotes in Anoxic Sediment of the Saline Meromictic Lake Namako-ike (Japan): On the Detection of Anaerobic or Anoxic-tolerant Lineages of Eukaryotes. Protist 2007; 158:51-64. [PMID: 16952482 DOI: 10.1016/j.protis.2006.07.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Accepted: 07/09/2006] [Indexed: 11/20/2022]
Abstract
Available sequence data on eukaryotic small-subunit ribosomal DNA (SSU rDNA) directly retrieved from various environments have increased recently, and the diversity of microbial eukaryotes (protists) has been shown to be much greater than previously expected. However, the molecular information accumulated to date does still not thoroughly reveal ecological distribution patterns of microbial eukaryotes. In the ongoing challenge to detect anaerobic or anoxic-tolerant lineages of eukaryotes, we directly extracted DNA from the anoxic sediment of a saline meromictic lake, constructed genetic libraries of PCR-amplified SSU rDNA, and performed phylogenetic analyses with the cloned SSU rDNA sequences. Although a few sequences could not be confidently assigned to any major eukaryotic groups in the analyses and are debatable regarding their taxonomic positions, most sequences obtained have affiliations with known major lineages of eukaryotes (Cercozoa, Alveolata, Stramenopiles, and Opisthokonta). Among these sequences, some branched with lineages predominantly composed of uncultured environmental clones retrieved from other anoxic environments, while others were closely related to those of eukaryotic parasites (e.g. Phytomyxea of Cercozoa, Gregarinea of Alveolata, and Ichthyosporea of Opisthokonta).
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Affiliation(s)
- Kiyotaka Takishita
- Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan.
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van der Giezen M, Tovar J, Clark CG. Mitochondrion‐Derived Organelles in Protists and Fungi. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 244:175-225. [PMID: 16157181 DOI: 10.1016/s0074-7696(05)44005-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The mitochondrion is generally considered to be a defining feature of eukaryotic cells, yet most anaerobic eukaryotes lack this organelle. Many of these were previously thought to derive from eukaryotes that diverged prior to acquisition of the organelle through endosymbiosis. It is now known that all extant eukaryotes are descended from an ancestor that had a mitochondrion and that in anaerobic eukaryotes the organelle has been modified into either hydrogenosomes, which continue to generate energy for the host cell, or mitosomes, which do not. These organelles have each arisen independently several times. Recent evidence suggests a shared derived characteristic that may be responsible for the retention of the organelles in the absence of the better-known mitochondrial functions--iron-sulfur cluster assembly. This review explores the events leading to this new understanding of mitochondrion-derived organelles in amitochondriate eukaryotes, the current state of our knowledge, and future areas for investigation.
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Affiliation(s)
- Mark van der Giezen
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
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Nasirudeen AMA, Tan KSW. Isolation and characterization of the mitochondrion-like organelle from Blastocystis hominis. J Microbiol Methods 2004; 58:101-9. [PMID: 15177908 DOI: 10.1016/j.mimet.2004.03.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 03/06/2004] [Accepted: 03/11/2004] [Indexed: 11/18/2022]
Abstract
Blastocystis hominis in an unusual protozoan parasite of the human intestinal tract. Previous studies have described the presence of mitochondrial-like structures despite the anaerobic nature of the organism. In this study, we describe a simple and rapid technique to isolate and characterize mitochondrion-like organelles (MLO) from B. hominis. The parasite was disrupted using glass beads and the MLO were collected and purified using a sucrose gradient. Negative staining and transmission electron microscopy of the isolated organelles showed mitochondrial-like structures. B. hominis cells were stained with rhodamine 123 and MitoLight to show the presence of transmembrane potential of the MLO. DAPI staining of the cells suggested the presence of DNA in the MLO. Though brief reports have been made in literature, this study is the first to describe a technique for the isolation of the MLO from this organism. Using this technique of isolation, major metabolic functions of the organelle, their associated macromolecules and intra-mitochondrial location can be extensively studied. The role of MLO in this anaerobic protozoan can be widely investigated using this protocol.
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Affiliation(s)
- A M A Nasirudeen
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, 117597 Singapore
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Lloyd D, Harris JC, Biagini GA, Hughes MR, Maroulis S, Bernard C, Wadley RB, Edwards MR. The plasma membrane of microaerophilic protists: oxidative and nitrosative stress. Microbiology (Reading) 2004; 150:1183-1190. [PMID: 15133079 DOI: 10.1099/mic.0.26834-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The trans-plasma-membrane electrochemical potential of microaerophilic protists was monitored by the use of voltage-sensitive charged lipophilic fluorophores; of the many available probes, the anionic oxonol dye bis(1,3-dibarbituric acid)-trimethine oxonol [DiBAC4(3)] is an example of one which has been successfully employed using fluorescence microscopy, confocal laser-scanning microscopy and flow cytometry. Several microaerophilic protists have been investigated with this dye; these were Giardia intestinalis, Trichomonas vaginalis, Tritrichomonas foetus, Hexamita inflata and Mastigamoeba punctachora. Under conditions where they exhibit normal vitality, these organisms exclude DiBAC4(3) by virtue of their maintenance of a plasma-membrane potential (negative inside). Uptake of the fluorophore is indicative of disturbance to this membrane (i.e. by inhibition of pump/leak balance, blockage of channels or generation of ionic leaks), and is indicative of metabolic perturbation or environmental stress. Here, it is shown that oxidative or nitrosative stress depolarizes the plasma membranes of the aforementioned O2-sensitive organisms and allows DiBAC4(3) influx. Oxonol uptake thereby provides a sensitive and early indication of plasma-membrane perturbation by agents that may lead to cytotoxicity and eventually to cell death by necrotic or apoptotic pathways.
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Affiliation(s)
- D Lloyd
- Microbiology (BIOSI 1) Main Building, Cardiff University, PO Box 915, Cardiff CF10 3TL, UK
| | - J C Harris
- Microbiology (BIOSI 1) Main Building, Cardiff University, PO Box 915, Cardiff CF10 3TL, UK
| | - G A Biagini
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia
| | - M R Hughes
- Department of Chemistry, King's College University of London, Strand, London WC2R 2LS, UK
| | - S Maroulis
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia
| | - C Bernard
- School of Science, Parramatta Campus, University of Western Sydney, Australia
| | - R B Wadley
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia
| | - M R Edwards
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia
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Embley TM, van der Giezen M, Horner DS, Dyal PL, Foster P. Mitochondria and hydrogenosomes are two forms of the same fundamental organelle. Philos Trans R Soc Lond B Biol Sci 2003; 358:191-201; discussion 201-2. [PMID: 12594927 PMCID: PMC1693103 DOI: 10.1098/rstb.2002.1190] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Published data suggest that hydrogenosomes, organelles found in diverse anaerobic eukaryotes that make energy and hydrogen, were once mitochondria. As hydrogenosomes generally lack a genome, the conversion is probably one way. The sources of the key hydrogenosomal enzymes, pyruvate : ferredoxin oxidoreductase (PFO) and hydrogenase, are not resolved by current phylogenetic analyses, but it is likely that both were present at an early stage of eukaryotic evolution. Once thought to be restricted to a few unusual anaerobic eukaryotes, the proteins are intimately integrated into the fabric of diverse eukaryotic cells, where they are targeted to different cell compartments, and not just hydrogenosomes. There is no evidence supporting the view that PFO and hydrogenase originated from the mitochondrial endosymbiont, as posited by the hydrogen hypothesis for eukaryogenesis. Other organelles derived from mitochondria have now been described in anaerobic and parasitic microbial eukaryotes, including species that were once thought to have diverged before the mitochondrial symbiosis. It thus seems possible that all eukaryotes may eventually be shown to contain an organelle of mitochondrial ancestry, to which different types of biochemistry can be targeted. It remains to be seen if, despite their obvious differences, this family of organelles shares a common function of importance for the eukaryotic cell, other than energy production, that might provide the underlying selection pressure for organelle retention.
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Affiliation(s)
- T Martin Embley
- Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
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Andersson SGE, Karlberg O, Canbäck B, Kurland CG. On the origin of mitochondria: a genomics perspective. Philos Trans R Soc Lond B Biol Sci 2003; 358:165-77; discussion 177-9. [PMID: 12594925 PMCID: PMC1693097 DOI: 10.1098/rstb.2002.1193] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The availability of complete genome sequence data from both bacteria and eukaryotes provides information about the contribution of bacterial genes to the origin and evolution of mitochondria. Phylogenetic analyses based on genes located in the mitochondrial genome indicate that these genes originated from within the alpha-proteobacteria. A number of ancestral bacterial genes have also been transferred from the mitochondrial to the nuclear genome, as evidenced by the presence of orthologous genes in the mitochondrial genome in some species and in the nuclear genome of other species. However, a multitude of mitochondrial proteins encoded in the nucleus display no homology to bacterial proteins, indicating that these originated within the eukaryotic cell subsequent to the acquisition of the endosymbiont. An analysis of the expression patterns of yeast nuclear genes coding for mitochondrial proteins has shown that genes predicted to be of eukaryotic origin are mainly translated on polysomes that are free in the cytosol whereas those of putative bacterial origin are translated on polysomes attached to the mitochondrion. The strong relationship with alpha-proteobacterial genes observed for some mitochondrial genes, combined with the lack of such a relationship for others, indicates that the modern mitochondrial proteome is the product of both reductive and expansive processes.
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Affiliation(s)
- Siv G E Andersson
- Department of Molecular Evolution, University of Uppsala, Uppsala S-75124, Sweden.
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Lloyd D, Harris JC, Maroulis S, Wadley R, Ralphs JR, Hann AC, Turner MP, Edwards MR. The "primitive" microaerophile Giardia intestinalis (syn. lamblia, duodenalis) has specialized membranes with electron transport and membrane-potential-generating functions. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1349-1354. [PMID: 11988508 DOI: 10.1099/00221287-148-5-1349] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Here it is shown that the flagellated protozoon Giardia intestinalis, commonly regarded as an early branching eukaryote because of its lack of mitochondria, has membraneous structures that partition the cationic, membrane-potential-sensitive fluorophore rhodamine 123. This organism also reduces a tetrazolium fluorogen at discrete plasma-membrane-associated sites. That these functions occur in distinctive specialized membrane systems supports the growing evidence that G. intestinalis may not be primitive, but is derived from an aerobic, mitochondria-containing flagellate.
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Affiliation(s)
- David Lloyd
- School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Janine C Harris
- School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Sarah Maroulis
- Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia
| | - Ron Wadley
- Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia
| | - James R Ralphs
- School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Ao C Hann
- School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Michael P Turner
- School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Michael R Edwards
- Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia
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Lloyd D, Ralphs JR, Harris JC. Giardia intestinalis, a eukaryote without hydrogenosomes, produces hydrogen. MICROBIOLOGY (READING, ENGLAND) 2002; 148:727-733. [PMID: 11882707 DOI: 10.1099/00221287-148-3-727] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The microaerophilic flagellated protist Giardia intestinalis, the commonest protozoal agent of intestinal infections worldwide, is of uncertain phylogeny, but is usually regarded as the earliest branching of the eukaryotic clades. Under strictly anaerobic conditions, a mass spectrometric investigation of gas production indicated a low level of generation of dihydrogen (2 nmol x min(-1) per 10(7) organisms), about 10-fold lower than that in Trichomonas vaginalis under similar conditions. Hydrogen evolution was O2 sensitive, and inhibited by 100 microM metronidazole. Fluorescent labelling of G. intestinalis cells using monoclonal antibodies to typical hydrogenosomal enzymes from T. vaginalis (malate enzyme, and succinyl-CoA synthetase alpha and beta subunits), and to the large-granule fraction (hydrogenosome-enriched, also from T. vaginalis) gave no discrete localization of epitopes. Cell-free extracts prepared under anaerobic conditions showed the presence of a CO-sensitive hydrogenase activity. This first report of hydrogen production in a eukaryote with no recognizable hydrogenosomes raises further questions about the early branching status of G. intestinalis; the physiological characterization of its hydrogenase, and its recently elucidated gene sequence, will aid further phylogenetic investigations.
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Affiliation(s)
- David Lloyd
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - James R Ralphs
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Janine C Harris
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
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Abstract
The endosymbiotic theory for the origin of mitochondria requires substantial modification. The three identifiable ancestral sources to the proteome of mitochondria are proteins descended from the ancestral alpha-proteobacteria symbiont, proteins with no homology to bacterial orthologs, and diverse proteins with bacterial affinities not derived from alpha-proteobacteria. Random mutations in the form of deletions large and small seem to have eliminated nonessential genes from the endosymbiont-mitochondrial genome lineages. This process, together with the transfer of genes from the endosymbiont-mitochondrial genome to nuclei, has led to a marked reduction in the size of mitochondrial genomes. All proteins of bacterial descent that are encoded by nuclear genes were probably transferred by the same mechanism, involving the disintegration of mitochondria or bacteria by the intracellular membranous vacuoles of cells to release nucleic acid fragments that transform the nuclear genome. This ongoing process has intermittently introduced bacterial genes to nuclear genomes. The genomes of the last common ancestor of all organisms, in particular of mitochondria, encoded cytochrome oxidase homologues. There are no phylogenetic indications either in the mitochondrial proteome or in the nuclear genomes that the initial or subsequent function of the ancestor to the mitochondria was anaerobic. In contrast, there are indications that relatively advanced eukaryotes adapted to anaerobiosis by dismantling their mitochondria and refitting them as hydrogenosomes. Accordingly, a continuous history of aerobic respiration seems to have been the fate of most mitochondrial lineages. The initial phases of this history may have involved aerobic respiration by the symbiont functioning as a scavenger of toxic oxygen. The transition to mitochondria capable of active ATP export to the host cell seems to have required recruitment of eukaryotic ATP transport proteins from the nucleus. The identity of the ancestral host of the alpha-proteobacterial endosymbiont is unclear, but there is no indication that it was an autotroph. There are no indications of a specific alpha-proteobacterial origin to genes for glycolysis. In the absence of data to the contrary, it is assumed that the ancestral host cell was a heterotroph.
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Affiliation(s)
- C G Kurland
- Department of Molecular Evolution, Evolutionary Biology Centre, University of Uppsala, Uppsala SE 752 36, Lund University, Lund SE 223 62, Sweden.
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Confocal laser scanning microscopy of trichomonads: Hydrogenosomes store calcium and show a membrane potential. Eur J Protistol 1998. [DOI: 10.1016/s0932-4739(98)80003-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Scott DA, Docampo R, Benchimol M. Analysis of the uptake of the fluorescent marker 2',7'-bis-(2-carboxyethyl)-5(and-6)-carboxyfluorescein (BCECF) by hydrogenosomes in Trichomonas vaginalis. Eur J Cell Biol 1998; 76:139-45. [PMID: 9696354 DOI: 10.1016/s0171-9335(98)80027-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The fluorescent dye 2',7'-bis-(2-carboxyethyl)-5(and-6)-carboxyfluorescein (BCECF) has been widely used as an indicator of cytosolic pH. Here we report that BCECF localizes to hydrogenosomes (hydrogen-generating organelles found in several phylogenetically separate groups of anaerobic protists) in Trichomonas vaginalis, where it was observable by fluorescence microscopy. Its cellular location was confirmed by treatment of BCECF-loaded cells with diaminobenzidine and hydrogen peroxide together with UV illumination. This produced an osmiophilic precipitate in the matrix of hydrogenosomes, observable by electron microscopy. Use of a short (7.5 min) loading period, loading on ice, use of concentrations of BCECF (acetoxymethyl ester) down to 10 nM, and inclusion of the anion channel blockers probenicid or sulfinpyrazone, or the K+/H+ ionophore nigericin in the loading buffer all failed to prevent hydrogenosomal accumulation of BCECF. This uptake was best observed when intact cells were loaded with the ester form of BCECF, but could also be seen using free BCECF following either incubation with ruptured cells or electroporation of intact cells. Hydrogenosomal BCECF loading was also obtained with washed cell lysates, without cytoplasm or metabolic substrates. We tested a range of other fluorogenic dyes designed for cytosolic labeling, and found that the calcium indicator fura-2 (acetoxymethyl ester) and the cell viability marker fluorescein diacetate also labeled hydrogenosomes. The results illustrate a novel use for BCECF as a fluorescent marker for hydrogenosomes (the first such marker), but present a warning against the indiscriminate use of fluorogenic ester dyes to measure properties of the cytosol in hydrogenosome-containing organisms - the dyes may also be indicating the properties of the hydrogenosome.
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Affiliation(s)
- D A Scott
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA
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Embley T, Horner D, Hirt R. Anaerobic eukaryote evolution: hydrogenosomes as biochemically modified mitochondria? Trends Ecol Evol 1997; 12:437-41. [DOI: 10.1016/s0169-5347(97)01208-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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