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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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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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Hutson KS, Cable J, Grutter AS, Paziewska-Harris A, Barber I. Aquatic Parasite Cultures and Their Applications. Trends Parasitol 2018; 34:1082-1096. [PMID: 30473011 DOI: 10.1016/j.pt.2018.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/19/2018] [Accepted: 09/24/2018] [Indexed: 12/17/2022]
Abstract
In this era of unprecedented growth in aquaculture and trade, aquatic parasite cultures are essential to better understand emerging diseases and their implications for human and animal health. Yet culturing parasites presents multiple challenges, arising from their complex, often multihost life cycles, multiple developmental stages, variable generation times and reproductive modes. Furthermore, the essential environmental requirements of most parasites remain enigmatic. Despite these inherent difficulties, in vivo and in vitro cultures are being developed for a small but growing number of aquatic pathogens. Expanding this resource will facilitate diagnostic capabilities and treatment trials, thus supporting the growth of sustainable aquatic commodities and communities.
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Affiliation(s)
- Kate S Hutson
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia.
| | - Joanne Cable
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Alexandra S Grutter
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Iain Barber
- School of Animal, Rural and Environmental Sciences, College of Science and Technology, Nottingham Trent University, NG25 0QF, UK
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Poynton SL, Ostrenga L, Witwer KW. Swarming and Aggregation in the Parasitic Diplomonad Flagellate Spironucleus vortens. J Eukaryot Microbiol 2018; 66:545-552. [PMID: 30341793 DOI: 10.1111/jeu.12695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/24/2018] [Accepted: 10/01/2018] [Indexed: 11/30/2022]
Abstract
Pathogenicity, evolutionary history, and unusual cell organization of diplomonads are well known, particularly for Giardia and Spironucleus; however, behavior of these aerotolerant anaerobes is largely unknown. Addressing this deficit, we studied behavior of the piscine diplomonad Spironucleus vortens (ATCC 50386) in in vitro culture. Spironucleus vortens trophozoites from Angelfish, Pterophyllum scalare, were maintained axenically in modified liver digest, yeast extract, and iron (LYI) medium, at 22 °C in the dark, and subcultured weekly. Cultures were monitored every 1-2 d, by removing an aliquot, and loading cells into a hemocytometer chamber, or onto a regular microscope slide. We observed three distinct swimming behaviors: (i) spontaneous formation of swarms, reaching 200 μm in diameter, persisting for up to several min in situ, (ii) directional movement of the swarm, via collective motility, and (iii) independent swimming of trophozoites to form a band (aggregation), presumably at the location of optimal environmental conditions. These behaviors have not previously been reported in Spironucleus. The observation that flagellate motility can change, from individual self-propulsion to complex collective swarming motility, prompts us to advocate S. vortens as a new model for study of group behavioral dynamics, complementing emerging studies of collective swimming in flagellated bacteria.
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Affiliation(s)
- Sarah L Poynton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 833 North Broadway, Baltimore, 21205, Maryland
| | - Lauren Ostrenga
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 833 North Broadway, Baltimore, 21205, Maryland
| | - Kenneth W Witwer
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 833 North Broadway, Baltimore, 21205, Maryland.,Department of Neurology, Johns Hopkins University School of Medicine, 833 North Broadway, Baltimore, 21205, Maryland
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Lloyd D, Lewis IB, Williams CF, Hayes AJ, Symons H, Hill EC. Motility of the diplomonad fish parasite Spironucleus vortens through thixotropic solid media. Microbiology (Reading) 2015; 161:213-218. [DOI: 10.1099/mic.0.082529-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- David Lloyd
- School of Biosciences, Cardiff University, Main Building, Museum Avenue, Cathays Park, Cardiff CF10 3AT, Wales, UK
| | - Iwan B. Lewis
- School of Biosciences, Cardiff University, Main Building, Museum Avenue, Cathays Park, Cardiff CF10 3AT, Wales, UK
| | - Catrin F. Williams
- School of Biosciences, Cardiff University, Main Building, Museum Avenue, Cathays Park, Cardiff CF10 3AT, Wales, UK
| | - Anthony J. Hayes
- School of Biosciences, Cardiff University, Main Building, Museum Avenue, Cathays Park, Cardiff CF10 3AT, Wales, UK
| | - Hannah Symons
- ECHA Microbiology Ltd, Units 22 and 23, Willowbrook Technology Park, Llandogo Road, St Mellons, Cardiff CF3 0EF, Wales, UK
| | - Edward C. Hill
- ECHA Microbiology Ltd, Units 22 and 23, Willowbrook Technology Park, Llandogo Road, St Mellons, Cardiff CF3 0EF, Wales, UK
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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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Williams C, Lloyd D, Kolarich D, Alagesan K, Duchêne M, Cable J, Williams D, Leitsch D. Disrupted intracellular redox balance of the diplomonad fish parasite Spironucleus vortens by 5-nitroimidazoles and garlic-derived compounds. Vet Parasitol 2012; 190:62-73. [DOI: 10.1016/j.vetpar.2012.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/10/2012] [Accepted: 05/11/2012] [Indexed: 01/22/2023]
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Stable transfection of the diplomonad parasite Spironucleus salmonicida. EUKARYOTIC CELL 2012; 11:1353-61. [PMID: 22983987 DOI: 10.1128/ec.00179-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Eukaryotic microbes are highly diverse, and many lineages remain poorly studied. One such lineage, the diplomonads, a group of binucleate heterotrophic flagellates, has been studied mainly due to the impact of Giardia intestinalis, an intestinal, diarrhea-causing parasite in humans and animals. Here we describe the development of a stable transfection system for use in Spironucleus salmonicida, a diplomonad that causes systemic spironucleosis in salmonid fish. We designed vectors in cassette format carrying epitope tags for localization (3×HA [where HA is hemagglutinin], 2× Escherichia coli OmpF linker and mouse langerin fusion sequence [2×OLLAS], 3×MYC) and purification of proteins (2× Strep-Tag II-FLAG tandem-affinity purification tag or streptavidin binding peptide-glutathione S-transferase [SBP-GST]) under the control of native or constitutive promoters. Three selectable gene markers, puromycin acetyltransferase (pac), blasticidin S-deaminase (bsr), and neomycin phosphotransferase (nptII), were successfully applied for the generation of stable transfectants. Site-specific integration on the S. salmonicida chromosome was shown to be possible using the bsr resistance gene. We epitope tagged six proteins and confirmed their expression by Western blotting. Next, we demonstrated the utility of these vectors by recording the subcellular localizations of the six proteins by laser scanning confocal microscopy. Finally, we described the creation of an S. salmonicida double transfectant suitable for colocalization studies. The transfection system described herein and the imminent completion of the S. salmonicida genome will make it possible to use comparative genomics as an investigative tool to explore specific, as well as general, diplomonad traits, benefiting research on both Giardia and Spironucleus.
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Carbohydrate and amino acid metabolism of Spironucleus vortens. Exp Parasitol 2011; 129:17-26. [DOI: 10.1016/j.exppara.2011.05.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 05/24/2011] [Accepted: 05/31/2011] [Indexed: 11/18/2022]
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Millet CO, Lloyd D, Williams C, Williams D, Evans G, Saunders RA, Cable J. Effect of garlic and allium-derived products on the growth and metabolism of Spironucleus vortens. Exp Parasitol 2011; 127:490-9. [DOI: 10.1016/j.exppara.2010.10.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 09/27/2010] [Accepted: 10/11/2010] [Indexed: 11/28/2022]
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