1
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Affiliation(s)
- L. A. Castlebury
- Dept. of Plant Pathology, University of Illinois, Urbana, Illinois 61801
| | - L. L. Domier
- USDA-ARS, Dept. of Crop Sciences, University of Illinois, Urbana, Illinois 61801
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2
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Light-dependent processes on the cathode enhance the electrical outputs of sediment microbial fuel cells. Bioelectrochemistry 2018; 122:1-10. [DOI: 10.1016/j.bioelechem.2018.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 02/15/2018] [Accepted: 02/25/2018] [Indexed: 11/22/2022]
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3
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Affiliation(s)
| | | | - R.L. Gilbertson
- Division of Plant Pathology and Microbiology, Department of Plant Sciences, The University of Arizona, Tucson, Arizona 85721
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4
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McGurk ES, Ford S, Bushek D. Unusually abundant and large ciliate xenomas in oysters, Crassostrea virginica , from Great Bay, New Hampshire, USA. J Invertebr Pathol 2016; 137:23-32. [DOI: 10.1016/j.jip.2016.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 11/28/2022]
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Moon E, Nam SW, Shin W, Park MG, Coats DW. Do All Dinoflagellates have an Extranuclear Spindle? Protist 2015; 166:569-84. [PMID: 26491972 DOI: 10.1016/j.protis.2015.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/01/2015] [Accepted: 08/25/2015] [Indexed: 01/20/2023]
Abstract
The syndinean dinoflagellates are a diverse assemblage of alveolate endoparasites that branch basal to the core dinoflagellates. Because of their phylogenetic position, the syndineans are considered key model microorganisms in understanding early evolution in the dinoflagellates. Closed mitosis with an extranuclear spindle that traverses the nucleus in cytoplasmic grooves or tunnels is viewed as one of the morphological features shared by syndinean and core dinoflagellates. Here we describe nuclear morphology and mitosis in the syndinean dinoflagellate Amoebophrya sp. from Akashiwo sanguinea, a member of the A. ceratii complex, as revealed by protargol silver impregnation, DNA specific fluorochromes, and transmission electron microscopy. Our observations show that not all species classified as dinoflagellates have an extranuclear spindle. In Amoebophrya sp. from A. sanguinea, an extranuclear microtubule cylinder located in a depression in the nuclear surface during interphase moves into the nucleoplasm via sequential membrane fusion events and develops into an entirely intranuclear spindle. Results suggest that the intranuclear spindle of Amoebophrya spp. may have evolved from an ancestral extranuclear spindle and indicate the need for taxonomic revision of the Amoebophryidae.
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Affiliation(s)
- Eunyoung Moon
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Seung Won Nam
- Department of Biological Science, Chungnam National University, Daejeon 306-764, Republic of Korea
| | - Woongghi Shin
- Department of Biological Science, Chungnam National University, Daejeon 306-764, Republic of Korea
| | - Myung Gil Park
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 500-757, Republic of Korea.
| | - D Wayne Coats
- Smithsonian Environmental Research Center, P.O. Box 28, 647 Contees Wharf Rd., Edgewater, MD 21037, USA
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Lynn DH, Coats DW. In Memoriam: John O. Corliss (1922-2014). J Eukaryot Microbiol 2015; 62:562-5. [PMID: 25809661 DOI: 10.1111/jeu.12212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Denis H Lynn
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - D Wayne Coats
- Smithsonian Environmental Research Center, P. O. Box 28, Edgewater, Maryland, 21037, USA
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Coats DW, Lynn DH. Obituary: John O. Corliss, February 23, 1922 - December 21, 2014. Protist 2015; 166:173-6. [PMID: 25768268 DOI: 10.1016/j.protis.2015.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 02/03/2015] [Indexed: 11/25/2022]
Affiliation(s)
- D Wayne Coats
- Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, Maryland 21037 USA; Present address: 318 Bayard Road, Lothian, Maryland 20711 USA.
| | - Denis H Lynn
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1 Canada; Present address: Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
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Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa. Eur J Protistol 2012; 49:115-78. [PMID: 23085100 DOI: 10.1016/j.ejop.2012.06.001] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/21/2012] [Accepted: 06/26/2012] [Indexed: 11/21/2022]
Abstract
I discuss how different feeding modes and related cellular structures map onto the eukaryote evolutionary tree. Centrally important for understanding eukaryotic cell diversity are Loukozoa: ancestrally biciliate phagotrophic protozoa possessing a posterior cilium and ventral feeding groove into which ciliary currents direct prey. I revise their classification by including all anaerobic Metamonada as a subphylum and adding Tsukubamonas. Loukozoa, often with ciliary vanes, are probably ancestral to all protozoan phyla except Euglenozoa and Percolozoa and indirectly to kingdoms Animalia, Fungi, Plantae, and Chromista. I make a new protozoan phylum Sulcozoa comprising subphyla Apusozoa (Apusomonadida, Breviatea) and Varisulca (Diphyllatea; Planomonadida, Discocelida, Mantamonadida; Rigifilida). Understanding sulcozoan evolution clarifies the origins from them of opisthokonts (animals, fungi, Choanozoa) and Amoebozoa, and their evolutionary novelties; Sulcozoa and their descendants (collectively called podiates) arguably arose from Loukozoa by evolving posterior ciliary gliding and pseudopodia in their ventral groove. I explain subsequent independent cytoskeletal modifications, accompanying further shifts in feeding mode, that generated Amoebozoa, Choanozoa, and fungi. I revise classifications of Choanozoa, Conosa (Amoebozoa), and basal fungal phylum Archemycota. I use Choanozoa, Sulcozoa, Loukozoa, and Archemycota to emphasize the need for simply classifying ancestral (paraphyletic) groups and illustrate advantages of this for understanding step-wise phylogenetic advances.
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Patterson DJ, Brugerolle G. The ultrastructural identity of Stephanopogon apogon and the relatedness of the genus to other kinds of protists. Eur J Protistol 2011. [PMID: 23195217 DOI: 10.1016/s0932-4739(88)80045-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ultrastructural organization of the marine benthic protist Stephanopogon apogon is presented. Emphasis is placed on the structure of the mouth, the cortex, and the locomotor flagella. Viewed with a light-microscope, individuals of this species closely resemble members of the phylum Ciliophora (in terms of ciliation, body form, and presence of a discrete mouth), but Stephanopogon cells are ultrastructurally unlike all ciliophora in respect of the oral apparatus, cortical organization, and locomotor systems. The proposition that Stephanopogon is related to Euglenozoa is discussed, and is found to be supported by a single character, the form of the mitochondrial cristae. Placement of Stephanopogon in the Euglenozoa is therefore deemed to be premature.
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Affiliation(s)
- D J Patterson
- Department of Zoology, University of Bristol, England
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The hemimastigophora (Hemimastix amphikineta nov. gen., nov. spec.), a new protistan phylum from gondwanian soils. Eur J Protistol 2011. [PMID: 23195325 DOI: 10.1016/s0932-4739(88)80027-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The morphology, morphogenesis and ultrastructure of Hemimastix amphikineta nov. gen., nov. spec, are described. This species occurred in some Australian and in 1 Chilean soil, but was absent from more than 1000 soil samples from Laurasian localities. Thus, it has probably a restricted Gondwanian distribution. Hemimastix amphikineta is a small (14-20 × 7-10 μn), colourless organism that looks distinctly Ciliophora-like because of its posteriorly located contractile vacuole and its 2 longitudinal somatic kineties each composed of about 12 cilia-like flagella. These 2 kineties are interposed between 2 large plicated and microtubule-bearing pellicular plates which are arranged inversely mirror-image like ("diagonal symmetry"). Hemimastix amphikineta has saccular to tubular mitochondrial cristae and complex extrusomes. It has 2 microtubular systems and a membranous sac associated with each kinetid. The nucleolus persists throughout nuclear division. A permanent cytostome-cytopharyngeal complex, pharyngeal rods, striated fibres, mastigonemes, and a paraflagellar rod are absent. This unique combination of characters dictates a very separate position for H. amphikineta within the known protists. Thus, the phylum Hemimastigophora nov. phylum (Hemimastigea nov. cl. and Hemimastigida nov. ord.), is established to include H. amphikineta and possibly Spironema multiciliatum Klebs, 1892. The structure of the pellicle and the nuclear apparatus of H. amphikineta indicate some relationship with the Euglenophyta. However, clear evidence for a certain affinity is lacking. Thus, the Hemimastigophora are placed in an incertae sedis position within the kingdom Protista Haeckel, 1866.
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11
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Lahr DJG, Parfrey LW, Mitchell EAD, Katz LA, Lara E. The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms. Proc Biol Sci 2011; 278:2081-90. [PMID: 21429931 PMCID: PMC3107637 DOI: 10.1098/rspb.2011.0289] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/04/2011] [Indexed: 11/12/2022] Open
Abstract
Amoebae are generally assumed to be asexual. We argue that this view is a relict of early classification schemes that lumped all amoebae together inside the 'lower' protozoa, separated from the 'higher' plants, animals and fungi. This artificial classification allowed microbial eukaryotes, including amoebae, to be dismissed as primitive, and implied that the biological rules and theories developed for macro-organisms need not apply to microbes. Eukaryotic diversity is made up of 70+ lineages, most of which are microbial. Plants, animals and fungi are nested among these microbial lineages. Thus, theories on the prevalence and maintenance of sex developed for macro-organisms should in fact apply to microbial eukaryotes, though the theories may need to be refined and generalized (e.g. to account for the variation in sexual strategies and prevalence of facultative sex in natural populations of many microbial eukaryotes). We use a revised phylogenetic framework to assess evidence for sex in several amoeboid lineages that are traditionally considered asexual, and we interpret this evidence in light of theories on the evolution of sex developed for macro-organisms. We emphasize that the limited data available for many lineages coupled with natural variation in microbial life cycles overestimate the extent of asexuality. Mapping sexuality onto the eukaryotic tree of life demonstrates that the majority of amoeboid lineages are, contrary to popular belief, anciently sexual, and that most asexual groups have probably arisen recently and independently. Additionally, several unusual genomic traits are prevalent in amoeboid lineages, including cyclic polyploidy, which may serve as alternative mechanisms to minimize the deleterious effects of asexuality.
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Affiliation(s)
- Daniel J. G. Lahr
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Laura Wegener Parfrey
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Edward A. D. Mitchell
- Laboratory of Soil Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Laura A. Katz
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | - Enrique Lara
- Laboratory of Soil Biology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
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12
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Lahr DJG, Parfrey LW, Mitchell EAD, Katz LA, Lara E. The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms. Proc Biol Sci 2011. [PMID: 21429931 DOI: 10.1098/rspb.2011.0289)10.1098/rspb.2011.0289)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Amoebae are generally assumed to be asexual. We argue that this view is a relict of early classification schemes that lumped all amoebae together inside the 'lower' protozoa, separated from the 'higher' plants, animals and fungi. This artificial classification allowed microbial eukaryotes, including amoebae, to be dismissed as primitive, and implied that the biological rules and theories developed for macro-organisms need not apply to microbes. Eukaryotic diversity is made up of 70+ lineages, most of which are microbial. Plants, animals and fungi are nested among these microbial lineages. Thus, theories on the prevalence and maintenance of sex developed for macro-organisms should in fact apply to microbial eukaryotes, though the theories may need to be refined and generalized (e.g. to account for the variation in sexual strategies and prevalence of facultative sex in natural populations of many microbial eukaryotes). We use a revised phylogenetic framework to assess evidence for sex in several amoeboid lineages that are traditionally considered asexual, and we interpret this evidence in light of theories on the evolution of sex developed for macro-organisms. We emphasize that the limited data available for many lineages coupled with natural variation in microbial life cycles overestimate the extent of asexuality. Mapping sexuality onto the eukaryotic tree of life demonstrates that the majority of amoeboid lineages are, contrary to popular belief, anciently sexual, and that most asexual groups have probably arisen recently and independently. Additionally, several unusual genomic traits are prevalent in amoeboid lineages, including cyclic polyploidy, which may serve as alternative mechanisms to minimize the deleterious effects of asexuality.
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Affiliation(s)
- Daniel J G Lahr
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA.
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13
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Genetic diversity of Labyrinthula terrestris, a newly emergent plant pathogen, and the discovery of new Labyrinthulid organisms. ACTA ACUST UNITED AC 2009; 113:1192-9. [DOI: 10.1016/j.mycres.2009.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 07/15/2009] [Accepted: 08/05/2009] [Indexed: 11/21/2022]
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14
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Lukashenko NP. Molecular evolution of ciliates (Ciliophora) and some related groups of protozoans. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409080018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Minge MA, Silberman JD, Orr RJS, Cavalier-Smith T, Shalchian-Tabrizi K, Burki F, Skjaeveland A, Jakobsen KS. Evolutionary position of breviate amoebae and the primary eukaryote divergence. Proc Biol Sci 2009; 276:597-604. [PMID: 19004754 DOI: 10.1098/rspb.2008.1358] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Integration of ultrastructural and molecular sequence data has revealed six supergroups of eukaryote organisms (excavates, Rhizaria, chromalveolates, Plantae, Amoebozoa and opisthokonts), and the root of the eukaryote evolutionary tree is suggested to lie between unikonts (Amoebozoa, opisthokonts) and bikonts (the other supergroups). However, some smaller lineages remain of uncertain affinity. One of these unassigned taxa is the anaerobic, free-living, amoeboid flagellate Breviata anathema, which is of key significance as it is unclear whether it is a unikont (i.e. possibly the deepest branching amoebozoan) or a bikont. To establish its evolutionary position, we sequenced thousands of Breviata genes and calculated trees using 78 protein sequences. Our trees and specific substitutions in the 18S RNA sequence indicate that Breviata is related to other Amoebozoa, thereby significantly increasing the cellular diversity of this phylum and establishing Breviata as a deep-branching unikont. We discuss the implications of these results for the ancestral state of Amoebozoa and eukaryotes generally, demonstrating that phylogenomics of phylogenetically 'nomadic' species can elucidate key questions in eukaryote evolution. Furthermore, mitochondrial genes among the Breviata ESTs demonstrate that Breviata probably contains a modified anaerobic mitochondrion. With these findings, remnants of mitochondria have been detected in all putatively deep-branching amitochondriate organisms.
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Affiliation(s)
- Marianne A Minge
- Department of Biology, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway
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Yubuki N, Leander BS. Ultrastructure and molecular phylogeny of Stephanopogon minuta: an enigmatic microeukaryote from marine interstitial environments. Eur J Protistol 2008; 44:241-53. [PMID: 18403188 DOI: 10.1016/j.ejop.2007.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2007] [Revised: 12/15/2007] [Accepted: 12/21/2007] [Indexed: 11/15/2022]
Abstract
Although Stephanopogon was described as a putative ciliate more than a century ago, its phylogenetic position within eukaryotes has remained unclear because of an unusual combination of morphological characteristics (e.g. a highly multiflagellated cell with discoidal mitochondrial cristae). Attempts to classify Stephanopogon have included placement with the Ciliophora, the Euglenozoa, the Heterolobosea and the Rhizaria. Most systematists have chosen, instead, to conservatively classify Stephanopogon as incertae sedis within eukaryotes. Despite the obvious utility of molecular phylogenetic data in resolving this issue, DNA sequences from Stephanopogon have yet to be published. Accordingly, we characterized the molecular phylogeny and ultrastructure of Stephanopogon minuta, a species we isolated from marine sediments in southern British Columbia, Canada. Our results showed that S. minuta shares several features with heteroloboseans, such as discoidal mitochondrial cristae, a heterolobosean-specific (17_1 helix) insertion in the small subunit ribosomal RNA gene (SSU rDNA) and the lack of canonical Golgi bodies. Molecular phylogenetic analyses of SSU rDNA demonstrated that S. minuta branches strongly within the Heterolobosea and specifically between two different tetraflagellated lineages, both named 'Percolomonas cosmopolitus.' Several ultrastructural features shared by S. minuta and P. cosmopolitus reinforced the molecular phylogenetic data and confirmed that Stephanopogon is a highly divergent multiflagellated heterolobosean that represents an outstanding example of convergent evolution with benthic eukaryovorous ciliates (Alveolata).
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Affiliation(s)
- Naoji Yubuki
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, The Departments of Botany and Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6 T 1Z4
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Heywood P, Rothschild LJ. Reconciliation of evolution and nomenclature among the higher taxa of protists*. Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.1987.tb00291.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Koziol C, Leys SP, Müller IM, Müller WEG. Cloning of Hsp70 genes from the marine sponges Sycon raphanus (Calcarea) and Rhabdocalyptus dawsoni (Hexactinellida). An approach to solve the phylogeny of sponges. Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.1997.tb00323.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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PATTERSON DAVIDJ, FENCHEL T. Insights into the evolution of heliozoa (Protozoa, Sarcodina) as provided by ultrastructural studies on a new species of flagellate from the genus Pteridomonas. Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.1985.tb00383.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Olsen MW. Labyrinthula terrestris: a new pathogen of cool-season turfgrasses. MOLECULAR PLANT PATHOLOGY 2007; 8:817-820. [PMID: 20507542 DOI: 10.1111/j.1364-3703.2007.00425.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
ABSTRACT A new disease of turfgrass known as rapid blight is caused by Labyrinthula terrestris, a newly described member of the Labyrinthulids. This unusual group of microorganisms previously has been found in marine systems, and L. terrestris is the only member of the genus Labyrinthula known to be a pathogen of terrestrial plants. Members of this genus are defined by the formation of ectoplasmic networks in which the unicellular somatic cells move or 'glide'. Infections of cool-season turfgrasses occur most commonly when they are irrigated with suboptimal irrigation water with elevated salinity. Disease has been observed in 11 states in the United States and in the United Kingdom. A phylogenetic study indicates that isolates from turfgrass in the United States fall firmly within a clade containing other Labyrinthula spp. and that they came from a common lineage. Its rapid emergence as a turfgrass pathogen may coincide with increased use of relatively high-salinity water or reclaimed water for irrigation. L. terrestris is a potential problem in susceptible turfgrass varieties wherever soil salinity is allowed to accumulate as a result of poor soil structure or suboptimal quality irrigation water is used for irrigation.
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Affiliation(s)
- Mary W Olsen
- Department of Plant Sciences, Forbes 303, The University of Arizona, Tucson, AZ 85721, USA
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LEE JOHNJ, SOLDO ANTHONYT, REISSER WERNER, LEE MONICAJ, JEON KW, GÖRTZ HANSDIETER. The Extent of Algal and Bacterial Endosymbioses in Protozoa1,2. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1985.tb04034.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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CORLISS JOHNO. Consideration of Taxonomic-Nomenclatural Problems Posed by Report of Myxosporidians with a Two-Host Life Cycle1. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1985.tb03083.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Andersen RA. Biology and systematics of heterokont and haptophyte algae. AMERICAN JOURNAL OF BOTANY 2004; 91:1508-1522. [PMID: 21652306 DOI: 10.3732/ajb.91.10.1508] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper, I review what is currently known of phylogenetic relationships of heterokont and haptophyte algae. Heterokont algae are a monophyletic group that is classified into 17 classes and represents a diverse group of marine, freshwater, and terrestrial algae. Classes are distinguished by morphology, chloroplast pigments, ultrastructural features, and gene sequence data. Electron microscopy and molecular biology have contributed significantly to our understanding of their evolutionary relationships, but even today class relationships are poorly understood. Haptophyte algae are a second monophyletic group that consists of two classes of predominately marine phytoplankton. The closest relatives of the haptophytes are currently unknown, but recent evidence indicates they may be part of a large assemblage (chromalveolates) that includes heterokont algae and other stramenopiles, alveolates, and cryptophytes. Heterokont and haptophyte algae are important primary producers in aquatic habitats, and they are probably the primary carbon source for petroleum products (crude oil, natural gas).
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Affiliation(s)
- Robert A Andersen
- Bigelow Laboratory for Ocean Sciences, P.O. Box 475, West Boothbay Harbor, Maine 04575 USA
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25
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Cavalier-Smith T, Chao EEY, Oates B. Molecular phylogeny of Amoebozoa and the evolutionary significance of the unikont Phalansterium. Eur J Protistol 2004. [DOI: 10.1016/j.ejop.2003.10.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Giardia lamblia is a common cause of diarrhea in humans and other mammals throughout the world. It can be distinguished from other Giardia species by light or electron microscopy. The two major genotypes of G. lamblia that infect humans are so different genetically and biologically that they may warrant separate species or subspecies designations. Trophozoites have nuclei and a well-developed cytoskeleton but lack mitochondria, peroxisomes, and the components of oxidative phosphorylation. They have an endomembrane system with at least some characteristics of the Golgi complex and encoplasmic reticulum, which becomes more extensive in encysting organisms. The primitive nature of the organelles and metabolism, as well as small-subunit rRNA phylogeny, has led to the proposal that Giardia spp. are among the most primitive eukaryotes. G. lamblia probably has a ploidy of 4 and a genome size of approximately 10 to 12 Mb divided among five chromosomes. Most genes have short 5' and 3' untranslated regions and promoter regions that are near the initiation codon. Trophozoites exhibit antigenic variation of an extensive repertoire of cysteine-rich variant-specific surface proteins. Expression is allele specific, and changes in expression from one vsp gene to another have not been associated with sequence alterations or gene rearrangements. The Giardia genome project promises to greatly increase our understanding of this interesting and enigmatic organism.
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Affiliation(s)
- R D Adam
- Department of Medicine, University of Arizona College of Medicine, 1501N. Campbell, Tucson, AZ 85724-5049, USA.
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27
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Abstract
Nucleariid amoebae are naked amoebae, generally characterized by a spherical or sometimes flattened body with radiating filopodia. Most species preferentially consume algal prey or cyanobacteria. Phylogenetic analyses of the small-subunit rRNA coding regions from four nucleariid amoebae place these species near the origin of the animal-fungal divergence, together with the choanoflagellate-Corallochytrium and the ichthyosporean clades. The species Nuclearia delicatula, N. moebiusi, and N. simplex form a monophyletic group, while ATCC 30864, tentatively but possibly incorrectly assigned to Nuclearia sp., represents a separate line of descent. These nucleariids are unrelated to the lineage containing the testate filose amoebae (Testaceafilosia). Our findings expand the morphological and phylogenetic diversity of protists at the animal-fungal divergence.
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Abstract
SUMMARY
Profound changes are occurring in the strategies that biotechnology-based industries are deploying in the search for exploitable biology and to discover new products and develop new or improved processes. The advances that have been made in the past decade in areas such as combinatorial chemistry, combinatorial biosynthesis, metabolic pathway engineering, gene shuffling, and directed evolution of proteins have caused some companies to consider withdrawing from natural product screening. In this review we examine the paradigm shift from traditional biology to bioinformatics that is revolutionizing exploitable biology. We conclude that the reinvigorated means of detecting novel organisms, novel chemical structures, and novel biocatalytic activities will ensure that natural products will continue to be a primary resource for biotechnology. The paradigm shift has been driven by a convergence of complementary technologies, exemplified by DNA sequencing and amplification, genome sequencing and annotation, proteome analysis, and phenotypic inventorying, resulting in the establishment of huge databases that can be mined in order to generate useful knowledge such as the identity and characterization of organisms and the identity of biotechnology targets. Concurrently there have been major advances in understanding the extent of microbial diversity, how uncultured organisms might be grown, and how expression of the metabolic potential of microorganisms can be maximized. The integration of information from complementary databases presents a significant challenge. Such integration should facilitate answers to complex questions involving sequence, biochemical, physiological, taxonomic, and ecological information of the sort posed in exploitable biology. The paradigm shift which we discuss is not absolute in the sense that it will replace established microbiology; rather, it reinforces our view that innovative microbiology is essential for releasing the potential of microbial diversity for biotechnology penetration throughout industry. Various of these issues are considered with reference to deep-sea microbiology and biotechnology.
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Bull AT, Ward AC, Goodfellow M. Search and discovery strategies for biotechnology: the paradigm shift. Microbiol Mol Biol Rev 2000; 64:573-606. [PMID: 10974127 PMCID: PMC99005 DOI: 10.1128/mmbr.64.3.573-606.2000] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Profound changes are occurring in the strategies that biotechnology-based industries are deploying in the search for exploitable biology and to discover new products and develop new or improved processes. The advances that have been made in the past decade in areas such as combinatorial chemistry, combinatorial biosynthesis, metabolic pathway engineering, gene shuffling, and directed evolution of proteins have caused some companies to consider withdrawing from natural product screening. In this review we examine the paradigm shift from traditional biology to bioinformatics that is revolutionizing exploitable biology. We conclude that the reinvigorated means of detecting novel organisms, novel chemical structures, and novel biocatalytic activities will ensure that natural products will continue to be a primary resource for biotechnology. The paradigm shift has been driven by a convergence of complementary technologies, exemplified by DNA sequencing and amplification, genome sequencing and annotation, proteome analysis, and phenotypic inventorying, resulting in the establishment of huge databases that can be mined in order to generate useful knowledge such as the identity and characterization of organisms and the identity of biotechnology targets. Concurrently there have been major advances in understanding the extent of microbial diversity, how uncultured organisms might be grown, and how expression of the metabolic potential of microorganisms can be maximized. The integration of information from complementary databases presents a significant challenge. Such integration should facilitate answers to complex questions involving sequence, biochemical, physiological, taxonomic, and ecological information of the sort posed in exploitable biology. The paradigm shift which we discuss is not absolute in the sense that it will replace established microbiology; rather, it reinforces our view that innovative microbiology is essential for releasing the potential of microbial diversity for biotechnology penetration throughout industry. Various of these issues are considered with reference to deep-sea microbiology and biotechnology.
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Affiliation(s)
- A T Bull
- Research School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom.
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Moriya M, Nakayama T, Inouye I. Ultrastructure and 18S rDNA sequence analysis of Wobblia lunata gen. et sp. nov., a new heterotrophic flagellate (Stramenopiles, Incertae sedis). Protist 2000; 151:41-55. [PMID: 10896132 DOI: 10.1078/1434-4610-00006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A new heterotrophic flagellate Wobblia lunata gen. et sp. nov. is described. This organism usually attaches to the substratum showing a wobbling motion, and sometimes glides on the substratum or swims freely in the medium. W. lunata has various features characteristic of the stramenopiles. These include a hairy flagellum with tripartite tubular hairs, a mitochondrion with tubular cristae, arrangement of flagellar apparatus components and a double helix in the flagellar transition zone. W. lunata shares a double helix with heterotrophic stramenopiles, including Developayella elegans, oomycetes, hyphochytrids, opalinids and proteromonads, and could be placed in the phylum Bigyra Cavalier-Smith. However, from 18S rDNA tree analysis, these organisms form two distantly-related clades in the stramenopiles, and Wobblia appears at the base of the stramenopiles. Evaluation of morphological features and comparison of 18S rDNA sequences indicate that W. lunata is a member of the stramenopiles, but it is distinct from any other stramenopiles so far described. Its phylogenetic position within the stramenopiles is uncertain and therefore W. lunata is described as a stramenopile incertae sedis.
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Affiliation(s)
- M Moriya
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
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31
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Berthe FC, Le Roux F, Peyretaillade E, Peyret P, Rodriguez D, Gouy M, Vivarès CP. Phylogenetic analysis of the small subunit ribosomal RNA of Marteilia refringens validates the existence of phylum Paramyxea (Desportes and Perkins, 1990). J Eukaryot Microbiol 2000; 47:288-93. [PMID: 10847346 DOI: 10.1111/j.1550-7408.2000.tb00049.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Marteilia refringens is recognized as one of the most significant pathogens of bivalve molluscs. The nucleotide sequence of the small subunit ribosomal RNA gene of Marteilia refringens is used to elucidate the phylogenetic position of the phylum Paramyxea. Genomic DNA was extracted from sporangia of Marteilia, purified from infected blue mussels, Mytilus edulis, and flat oysters, Ostrea edulis. The sequences obtained from Marteilia species purified from both oysters and mussels were identical. The sequence identity was confirmed by in situ hybridization using a DNA probe targeted to a variable region of the ribosomal DNA. The small subunit ribosomal RNA gene sequence of M. refringens is very different from all known sequences of eukaryotic organisms, including those of myxosporeans and haplosporeans. Therefore, the phylum Paramyxea should continue to be recognized as an independent eukaryotic phylum.
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Affiliation(s)
- F C Berthe
- Laboratoire de Génétique et Pathologie, IFREMER, La Tremblade, France.
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32
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Abstract
The discipline of evolutionary protistology has emerged in the past 30 yr. There is as yet no agreed view of how protists are interrelated or how they should be classified. The foundations of a stable taxonomic superstructure for the protists and other eukaryotes lie in cataloging the diversity of the major monophyletic lineages of these organisms. The use of common patterns of cell organization (ultrastructural identity) seems to provide us with the most robust hypotheses of such lineages. These lineages are placed in 71 groups without identifiable sister taxa. These groups are here referred to as "major building blocks." For the first time, the compositions, ultrastructural identities, synapomorphies (where available), and subgroups of the major building blocks are summarized. More than 200 further lineages without clear identities are listed. This catalog includes all known major elements of the comprehensive evolutionary tree of protists and eukaryotes. Different approaches among protistologists to issues of nomenclature, ranking, and definitions of these groups are discussed, with particular reference to two groups-the stramenopiles and the Archezoa. The concept of "extended in-group" is introduced to refer to in-groups and the most proximate sister group and to assist in identifying the hierarchical location of taxa.
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33
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Sauvant MP, Pepin D, Piccinni E. Tetrahymena pyriformis: a tool for toxicological studies. A review. CHEMOSPHERE 1999; 38:1631-1669. [PMID: 10070737 DOI: 10.1016/s0045-6535(98)00381-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Among protozoa, Tetrahymena pyriformis is the most commonly ciliated model used for laboratory research. After a brief description of the morphology and biology of Tetrahymena pyriformis, this article focuses on the most important and recent investigations performed with this species in toxicology and ecotoxicology. The methodological features of its culture, and main tests, based on cell growth rate, biochemical markers, behavioral changes and motility, are discussed. Examples of xenobiotics (organic and inorganic substances, pharmaceutical drugs, water pollutants) tested with Tetrahymena pyriformis are also given.
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Affiliation(s)
- M P Sauvant
- UFR Pharmacie, Laboratoire Hydrologie, Environnement et Santé Publique, Clermont-Ferrand, France
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34
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Van der Auwera G, Hofmann CJ, De Rijk P, De Wachter R. The origin of red algae and cryptomonad nucleomorphs: A comparative phylogeny based on small and large subunit rRNA sequences of Palmaria palmata, Gracilaria verrucosa, and the Guillardia theta nucleomorph. Mol Phylogenet Evol 1998; 10:333-42. [PMID: 10051386 DOI: 10.1006/mpev.1998.0544] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The complete large subunit rRNA sequences from the red algae Palmaria palmata and Gracilaria verrucosa, and from the nucleomorph of the cryptomonad Guillardia theta, were determined in order to assess their phylogenetic relationships relative to each other and to other eukaryotes. Neighbor-joining, maximum-parsimony, and maximum-likelihood trees were constructed on the basis of small subunit rRNA, large subunit rRNA, and a combination of both molecules. Our results support the hypothesis that the cryptomonad plastid is derived from a primitive red alga, in that an ancient common ancestor of rhodophytes and cryptomonad nucleomorphs is indicated. This cluster shows some affinity with chlorobionts, which could point to a monophyletic origin of green and red plastids. However, the exact branching order of the crown eukaryotes remains uncertain and further research is required.
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Affiliation(s)
- G Van der Auwera
- Department of Biochemistry, University of Antwerp (UIA), Universiteitsplein 1, Antwerpen, B 2610, Belgium
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35
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36
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Sprague V, Becnel JJ. Note on the Name-Author-Date Combination for the Taxon MICROSPORIDIES Balbiani, 1882, When Ranked as a Phylum. J Invertebr Pathol 1998; 71:91-4. [PMID: 9446742 DOI: 10.1006/jipa.1997.4702] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- V Sprague
- Center for Medical, Agricultural and Veterinary Entomology, U. S. Department of Agriculture, Gainesville, Florida, 32604
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37
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Simpson AG, Van Den Hoff J, Bernard C, Burton HR, Patterson DJ. The ultrastructure and systematic position of the euglenozoon Postgaardi mariagerensis, Fenchel et al. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0003-9365(97)80049-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Kamoun S, van West P, de Jong AJ, de Groot KE, Vleeshouwers VG, Govers F. A gene encoding a protein elicitor of Phytophthora infestans is down-regulated during infection of potato. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 1997; 10:13-20. [PMID: 9002268 DOI: 10.1094/mpmi.1997.10.1.13] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Most species of the genus Phytophthora produce 10-kDa extracellular protein elicitors, collectively termed elicitins. Elicitins induce hypersensitive response in a restricted number of plants, particularly in the genus Nicotiana within the Solanaceae family. A cDNA encoding INF1, the major secreted elicitin of Phytophthora infestans, a pathogen of solanaceous plants, was isolated and characterized. The expression of the corresponding inf1 gene during the disease cycle of P. infestans was analyzed. inf1 was shown to be expressed in mycelium grown in various culture media, whereas it was not expressed in sporangiospores, zoospores, cysts, and germinating cysts. In planta, during infection of potato, particularly during the biotrophic stage, expression of inf1 was down-regulated compared to in vitro. The highest levels of expression of inf1 were observed in in vitro grown mycelium and in late stages of infection when profuse sporulation and leaf necrosis occur. The potential role of INF1 as an elicitor in interactions between P. infestans and Solanum species was investigated. Nineteen lines, representing nine solanaceous species with various levels of resistance to P. infestans, were tested for response to an Escherichia coli expressed INF1. Within the genus Solanum, resistance to P. infestans did not appear to be mediated by a defense response elicited by INF1. However, INF1 recognition could be a component of nonhost resistance of tobacco to P. infestans.
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Affiliation(s)
- S Kamoun
- Department of Phytopathology, Wageningen Agricultural University, The Netherlands.
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40
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Analyses of heliozoan interrelationships: an example of the potentials and limitations of ultrastructural approaches to the study of protistan phylogeny. ACTA ACUST UNITED AC 1997. [DOI: 10.1098/rspb.1986.0026] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Concepts about specific relationships among various groups of protists are diverse and protist taxonomy is consequently unstable. In order to investigate the causes of this variety, data (mainly ultrastructural) relating to 198 characters of 25 species of heliozoa and other protozoa are analysed. Procedures are used which are compatible with numerical taxonomy (single linkage, complete linkage and group average cluster analyses), cladistic procedures (Camin–Sokal, Dollo and Wagner parsimony analyses) and evolutionary taxonomy (an intuitive tree). The results are presented as branching diagrams. There is no complete congruence among any of the techniques, but all give similar results in some important aspects. The Wagner and Dollo parsimony analyses give those results which are most credible. The results corroborate the view that several major traditional taxa of protozoa (the heliozoa, flagellates, amoebae and filose amoebae) are polyphyletic and require revision. All of the analyses identify the following clusters: actinophryid heliozoa, centrohelid heliozoa, chrysophyte flagellates, actinomonad and pedinellid flagellates and nucleariid filose amoebae. As there is no disagreement, these are confirmed as monophyletic taxa. There is a strong suggestion for a close relationship between dimorphid flagellates and desmothoracid heliozoa. There is some support for the suggestion that the actinophryid heliozoa are more closely related to actinomonad helioflagellates than to other heliozoa. The results are summarized as an unrooted ‘true tree'. The lack of agreement among the analyses appears not to be due to a lack of rigour in analytical procedures, but to an inadequate supply of data. The paucity of data cannot be compensated for by the application of repeatable techniques. Most relationships among high level protist taxa are likely to be (currently) obscured by similar limitations. Ultrastructural data are well suited to mapping out the diversity of protozoa. Electron microscopy currently appears to be the most valuable technique for investigating problems of evolutionary relationships of protists. Various hurdles to the development of a natural (phylogenetic) classification of protists are discussed.
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41
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Van der Auwera G, De Wachter R. Large-subunit rRNA sequence of the chytridiomycete Blastocladiella emersonii, and implications for the evolution of zoosporic fungi. J Mol Evol 1996; 43:476-83. [PMID: 8875862 DOI: 10.1007/bf02337520] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 5.8S and 28S ribosomal RNA sequences of the chytridiomycete Blastocladiella emersonii were determined. These data were combined with 18S rRNA sequences in order to carry out a phylogenetic analysis based on distance matrix, parsimony, and maximum likelihood methods. The new data confirmed that chytridiomycetes are true fungi and not protists, as was already suggested on the basis of biochemical, ultrastructural, and 18S rRNA data. Within the fungal clade, B. emersonii formed the first line of divergence. The position of the fungi within the eukaryotic "crown" taxa was also reassessed, and the alveolate-stramenopile cluster appeared as their sister group. The stramenopiles also comprise a number of zoosporic fungi, which resemble chytridiomycetes in so many respects, e.g., production of motile spores, thallus morphology, and absorptive nutrition, that they have been classified together with them in the past. This suggests that the possible common ancestor of the fungi, stramenopiles, and alveolates may have been a zoosporic fungus, which would mean that zoosporic fungi are paraphyletic instead of polyphyletic as previously suggested.
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Affiliation(s)
- G Van der Auwera
- Departement Biochemie, Universiteit Antwerpen (UIA), Universiteitsplein 1, B 2610 Antwerpen, Belgium
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42
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Viscogliosi E, Durieux I, Delgado-Viscogliosi P, Bayle D, Dive D. Phylogenetic implication of iron-containing superoxide dismutase genes from trichomonad species. Mol Biochem Parasitol 1996; 80:209-214. [PMID: 8892298 DOI: 10.1016/0166-6851(96)02685-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- E Viscogliosi
- Laboratoire de Biologie des Protistes, URA CNRS, Université Blaise Pascal de Clermont-Ferrand, Aubière, France
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43
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Rosati G, Giambelluca M, Taiti E. Epixenosomes: peculiar epibionts of the ciliate Euplotidium itoi: morphological and functional cell compartmentalization. Tissue Cell 1996; 28:313-20. [DOI: 10.1016/s0040-8166(96)80018-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/1995] [Accepted: 11/29/1995] [Indexed: 10/25/2022]
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44
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Abstract
The evolutionary relationships of four eukaryotic kingdoms--Animalia, Plantae, Fungi, and Protista--remain unclear. In particular, statistical support for the closeness of animals to fungi rather than to plants is lacking, and a preferred branching order of these and other eukaryotic lineages is still controversial even though molecular sequences from diverse eukaryotic taxa have been analyzed. We report a statistical analysis of 214 sequences of nuclear small-subunit ribosomal RNA (srRNA) gene undertaken to clarify these evolutionary relationships. We have considered the variability of substitution rates and the nonindependence of nucleotide substitution across sites in the srRNA gene in testing alternative hypotheses regarding the branching patterns of eukaryote phylogeny. We find that the rates of evolution among sites in the srRNA sequences vary substantially and are approximately gamma distributed with size and shape parameter equal to 0.76. Our results suggest that (1) the animals and true fungi are indeed closer to each other than to any other "crown" group in the eukaryote tree, (2) red algae are the closest relatives of animals, true fungi, and green plants, and (3) the heterokonts and alveolates probably evolved prior to the divergence of red algae and animal-fungus-green-plant lineages. Furthermore, our analyses indicate that the branching order of the eukaryotic lineages that diverged prior to the evolution of alveolates may be generally difficult to resolve with the srRNA sequence data.
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Affiliation(s)
- S Kumar
- Department of Biology, Pennsylvania State University, University Park 16802, USA
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45
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46
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Paquin B, Roewer I, Wang Z, Lang BF. A robust fungal phytogeny using the mitochondrially encoded NAD5 protein sequence. ACTA ACUST UNITED AC 1995. [DOI: 10.1139/b95-243] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We present a fungal phylogeny based on mitochondrial NAD5 (subunit of the NADH dehydrogenase) protein sequences. The tree topology is well supported by bootstrap analysis and mostly congruent with trees inferred from nuclear sequences, ultrastructural data, or mitochondrial COX1 and COX3 (subunits of the cytochrome oxidase) protein sequences. The NAD5 tree points to (i) an early divergence of the Chytridiomycetes, (ii) an appearance of Zygomycetes prior to the divergence of Ascomycetes and Basidiomycetes, and (iii) Oomycetes as clearly unrelated to fungi. In addition, this analysis predicts a common ancestor of fungi and animals, to the exclusion of green algae and plants. Our results reinforce the view that protein sequences are of high value in the reconstruction of the phylogenetic history of mitochondria. Key words: protein sequences, mitochondria, phylogeny, fungi, Oomycetes.
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47
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Delgado-Viscogliosi P, Brugerolle G, Viscogliosi E. Electrophoretic Mobility of Tubulin Subunits as a Criterion for Testing Relationships between Trichormonad Taxa. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0003-9365(11)80110-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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48
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Escalante AA, Ayala FJ. Evolutionary origin of Plasmodium and other Apicomplexa based on rRNA genes. Proc Natl Acad Sci U S A 1995; 92:5793-7. [PMID: 7597031 PMCID: PMC41587 DOI: 10.1073/pnas.92.13.5793] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have explored the evolutionary history of the Apicomplexa and two related protistan phyla, Dinozoa and Ciliophora, by comparing the nucleotide sequences of small subunit ribosomal RNA genes. We conclude that the Plasmodium lineage, to which the malarial parasites belong, diverged from other apicomplexan lineages (piroplasmids and coccidians) several hundred million years ago, perhaps even before the Cambrian. The Plasmodium radiation, which gave rise to several species parasitic to humans, occurred approximately 129 million years ago; Plasmodium parasitism of humans has independently arisen several times. The origin of apicomplexans (Plasmodium), dinoflagellates, and ciliates may be > 1 billion years old, perhaps older than the three multicellular kingdoms of animals, plants, and fungi. Digenetic parasitism independently evolved several times in the Apicomplexa.
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Affiliation(s)
- A A Escalante
- Department of Ecology and Evolutionary Biology, University of California, Irvine 92717, USA
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49
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50
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Preisfeld A, Ruppel HG. Detection of Sialic Acid and Glycosphingolipids in Euglena gracilis (Euglenozoa). ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0003-9365(11)80320-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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