1
|
Suzuki-Tellier S, Kiørboe T, Simpson AGB. The function of the feeding groove of 'typical excavate' flagellates. J Eukaryot Microbiol 2024; 71:e13016. [PMID: 38108228 DOI: 10.1111/jeu.13016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Phagotrophic flagellates are the main consumers of bacteria and picophytoplankton. Despite their ecological significance in the 'microbial loop', many of their predation mechanisms remain unclear. 'Typical excavates' bear a ventral groove, where prey is captured for ingestion. The consequences of feeding through a 'semi-rigid' furrow on the prey size range have not been explored. An unidentified moving element called 'the wave' that sweeps along the bottom of the groove toward the site of phagocytosis has been observed in a few species; its function is unclear. We investigated the presence, behavior, and function of the wave in four species from the three excavate clades (Discoba, Metamonada, and Malawimonadida) and found it present in all studied cases, suggesting the potential homology of this feature across all three groups. The wave displayed a species-specific behavior and was crucial for phagocytosis. The morphology of the feeding groove had an upper-prey size limit for successful prey captures, but smaller particles were not constrained. Additionally, the ingestion efficiencies were species dependent. By jointly studying these feeding traits, we speculate on adaptations to differences in food availability to better understand their ecological functions.
Collapse
Affiliation(s)
- Sei Suzuki-Tellier
- Centre for Ocean Life, DTU Aqua, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Thomas Kiørboe
- Centre for Ocean Life, DTU Aqua, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Alastair G B Simpson
- Department of Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
2
|
Torruella G, Galindo LJ, Moreira D, Ciobanu M, Heiss AA, Yubuki N, Kim E, López-García P. Expanding the molecular and morphological diversity of Apusomonadida, a deep-branching group of gliding bacterivorous protists. J Eukaryot Microbiol 2023; 70:e12956. [PMID: 36453005 DOI: 10.1111/jeu.12956] [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: 05/14/2022] [Revised: 09/13/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
Apusomonads are cosmopolitan bacterivorous biflagellate protists usually gliding on freshwater and marine sediment or wet soils. These nanoflagellates form a sister lineage to opisthokonts and may have retained ancestral features helpful to understanding the early evolution of this large supergroup. Although molecular environmental analyses indicate that apusomonads are genetically diverse, few species have been described. Here, we morphologically characterize 11 new apusomonad strains. Based on molecular phylogenetic analyses of the rRNA gene operon, we describe four new strains of the known species Multimonas media, Podomonas capensis, Apusomonas proboscidea, and Apusomonas australiensis, and rename Thecamonas oxoniensis as Mylnikovia oxoniensis n. gen., n. comb. Additionally, we describe four new genera and six new species: Catacumbia lutetiensis n. gen. n. sp., Cavaliersmithia chaoae n. gen. n. sp., Singekia montserratensis n. gen. n. sp., Singekia franciliensis n. gen. n. sp., Karpovia croatica n. gen. n. sp., and Chelonemonas dolani n. sp. Our comparative analysis suggests that apusomonad ancestor was a fusiform biflagellate with a dorsal pellicle, a plastic ventral surface, and a sleeve covering the anterior flagellum, that thrived in marine, possibly oxygen-poor, environments. It likely had a complex cell cycle with dormant and multiple fission stages, and sex. Our results extend known apusomonad diversity, allow updating their taxonomy, and provide elements to understand early eukaryotic evolution.
Collapse
Affiliation(s)
- Guifré Torruella
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Orsay, France.,Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain.,Institute for Research in Biomedicine (IRB), Barcelona, Spain
| | - Luis Javier Galindo
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Orsay, France.,Department of Zoology, University of Oxford, Oxford, UK
| | - David Moreira
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Orsay, France
| | - Maria Ciobanu
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Orsay, France
| | - Aaron A Heiss
- Department of Invertebrate Zoology, American Museum of Natural History, New York City, New York, USA.,Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Naoji Yubuki
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Orsay, France.,Bioimaging Facility, University of British Columbia, Vancouver, BC, Canada
| | - Eunsoo Kim
- Department of Invertebrate Zoology, American Museum of Natural History, New York City, New York, USA.,Department of Life Science & Division of EcoScience, Ewha Womans University, Seoul, South Korea
| | | |
Collapse
|
3
|
Ancient Origins of Cytoskeletal Crosstalk: Spectraplakin-like Proteins Precede the Emergence of Cortical Microtubule Stabilization Complexes as Crosslinkers. Int J Mol Sci 2022; 23:ijms23105594. [PMID: 35628404 PMCID: PMC9145010 DOI: 10.3390/ijms23105594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/12/2022] [Accepted: 05/12/2022] [Indexed: 11/17/2022] Open
Abstract
Adhesion between cells and the extracellular matrix (ECM) is one of the prerequisites for multicellularity, motility, and tissue specialization. Focal adhesions (FAs) are defined as protein complexes that mediate signals from the ECM to major components of the cytoskeleton (microtubules, actin, and intermediate filaments), and their mutual communication determines a variety of cellular processes. In this study, human cytoskeletal crosstalk proteins were identified by comparing datasets with experimentally determined cytoskeletal proteins. The spectraplakin dystonin was the only protein found in all datasets. Other proteins (FAK, RAC1, septin 9, MISP, and ezrin) were detected at the intersections of FAs, microtubules, and actin cytoskeleton. Homology searches for human crosstalk proteins as queries were performed against a predefined dataset of proteomes. This analysis highlighted the importance of FA communication with the actin and microtubule cytoskeleton, as these crosstalk proteins exhibit the highest degree of evolutionary conservation. Finally, phylogenetic analyses elucidated the early evolutionary history of spectraplakins and cortical microtubule stabilization complexes (CMSCs) as model representatives of the human cytoskeletal crosstalk. While spectraplakins probably arose at the onset of opisthokont evolution, the crosstalk between FAs and microtubules is associated with the emergence of metazoans. The multiprotein complexes contributing to cytoskeletal crosstalk in animals gradually gained in complexity from the onset of metazoan evolution.
Collapse
|
4
|
Cavalier-Smith T. Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi. PROTOPLASMA 2022; 259:487-593. [PMID: 34940909 PMCID: PMC9010356 DOI: 10.1007/s00709-021-01665-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/03/2021] [Indexed: 05/19/2023]
Abstract
I thoroughly discuss ciliary transition zone (TZ) evolution, highlighting many overlooked evolutionarily significant ultrastructural details. I establish fundamental principles of TZ ultrastructure and evolution throughout eukaryotes, inferring unrecognised ancestral TZ patterns for Fungi, opisthokonts, and Corticata (i.e., kingdoms Plantae and Chromista). Typical TZs have a dense transitional plate (TP), with a previously overlooked complex lattice as skeleton. I show most eukaryotes have centriole/TZ junction acorn-V filaments (whose ancestral function was arguably supporting central pair microtubule-nucleating sites; I discuss their role in centriole growth). Uniquely simple malawimonad TZs (without TP, simpler acorn) pinpoint the eukaryote tree's root between them and TP-bearers, highlighting novel superclades. I integrate TZ/ciliary evolution with the best multiprotein trees, naming newly recognised major eukaryote clades and revise megaclassification of basal kingdom Protozoa. Recent discovery of non-photosynthetic phagotrophic flagellates with genome-free plastids (Rhodelphis), the sister group to phylum Rhodophyta (red algae), illuminates plant and chromist early evolution. I show previously overlooked marked similarities in cell ultrastructure between Rhodelphis and Picomonas, formerly considered an early diverging chromist. In both a nonagonal tube lies between their TP and an annular septum surrounding their 9+2 ciliary axoneme. Mitochondrial dense condensations and mitochondrion-linked smooth endomembrane cytoplasmic partitioning cisternae further support grouping Picomonadea and Rhodelphea as new plant phylum Pararhoda. As Pararhoda/Rhodophyta form a robust clade on site-heterogeneous multiprotein trees, I group Pararhoda and Rhodophyta as new infrakingdom Rhodaria of Plantae within subkingdom Biliphyta, which also includes Glaucophyta with fundamentally similar TZ, uniquely in eukaryotes. I explain how biliphyte TZs generated viridiplant stellate-structures.
Collapse
|
5
|
Neumann JS, Desalle R, Narechania A, Schierwater B, Tessler M. Morphological Characters Can Strongly Influence Early Animal Relationships Inferred from Phylogenomic Data Sets. Syst Biol 2021; 70:360-375. [PMID: 32462193 PMCID: PMC7875439 DOI: 10.1093/sysbio/syaa038] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 12/19/2022] Open
Abstract
There are considerable phylogenetic incongruencies between morphological and phylogenomic data for the deep evolution of animals. This has contributed to a heated debate over the earliest-branching lineage of the animal kingdom: the sister to all other Metazoa (SOM). Here, we use published phylogenomic data sets ($\sim $45,000-400,000 characters in size with $\sim $15-100 taxa) that focus on early metazoan phylogeny to evaluate the impact of incorporating morphological data sets ($\sim $15-275 characters). We additionally use small exemplar data sets to quantify how increased taxon sampling can help stabilize phylogenetic inferences. We apply a plethora of common methods, that is, likelihood models and their "equivalent" under parsimony: character weighting schemes. Our results are at odds with the typical view of phylogenomics, that is, that genomic-scale data sets will swamp out inferences from morphological data. Instead, weighting morphological data 2-10$\times $ in both likelihood and parsimony can in some cases "flip" which phylum is inferred to be the SOM. This typically results in the molecular hypothesis of Ctenophora as the SOM flipping to Porifera (or occasionally Placozoa). However, greater taxon sampling improves phylogenetic stability, with some of the larger molecular data sets ($>$200,000 characters and up to $\sim $100 taxa) showing node stability even with $\geqq100\times $ upweighting of morphological data. Accordingly, our analyses have three strong messages. 1) The assumption that genomic data will automatically "swamp out" morphological data is not always true for the SOM question. Morphological data have a strong influence in our analyses of combined data sets, even when outnumbered thousands of times by molecular data. Morphology therefore should not be counted out a priori. 2) We here quantify for the first time how the stability of the SOM node improves for several genomic data sets when the taxon sampling is increased. 3) The patterns of "flipping points" (i.e., the weighting of morphological data it takes to change the inferred SOM) carry information about the phylogenetic stability of matrices. The weighting space is an innovative way to assess comparability of data sets that could be developed into a new sensitivity analysis tool. [Metazoa; Morphology; Phylogenomics; Weighting.].
Collapse
Affiliation(s)
- Johannes S Neumann
- Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024, USA
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Rob Desalle
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Apurva Narechania
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Bernd Schierwater
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
- ITZ, Division of Ecology and Evolution, Tierärztliche Hochschule Hannover, Bünteweg 9, 30559 Hannover, Germany
| | - Michael Tessler
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| |
Collapse
|
6
|
Evolution of the centrosome, from the periphery to the center. Curr Opin Struct Biol 2020; 66:96-103. [PMID: 33242728 DOI: 10.1016/j.sbi.2020.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 11/24/2022]
Abstract
Centrosomes are central organelles that organize microtubules (MTs) in animals, fungi and several other eukaryotic lineages. Despite an important diversity of structure, the centrosomes of different lineages share the same functions and part of their molecular components. To uncover how divergent centrosomes are related to each other, we need to trace the evolutionary history of MT organization. Careful assessment of cytoskeletal architecture in extant eukaryotic species can help us infer the ancestral state and identify the subsequent changes that took place during evolution. This led to the finding that the last common ancestor of all eukaryotes was very likely a biflagellate cell with a surprisingly complex cytoskeletal organization. Centrosomes are likely derived from the basal bodies of such flagellate, but when and how many times this happened remains unclear. Here, we discuss different hypotheses for how centrosomes evolved in a eukaryotic lineage called Amorphea, to which animals, fungi and amoebozoans belong.
Collapse
|
7
|
Heiss AA, Kolisko M, Ekelund F, Brown MW, Roger AJ, Simpson AGB. Combined morphological and phylogenomic re-examination of malawimonads, a critical taxon for inferring the evolutionary history of eukaryotes. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171707. [PMID: 29765641 PMCID: PMC5936906 DOI: 10.1098/rsos.171707] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/06/2018] [Indexed: 05/16/2023]
Abstract
Modern syntheses of eukaryote diversity assign almost all taxa to one of three groups: Amorphea, Diaphoretickes and Excavata (comprising Discoba and Metamonada). The most glaring exception is Malawimonadidae, a group of small heterotrophic flagellates that resemble Excavata by morphology, but branch with Amorphea in most phylogenomic analyses. However, just one malawimonad, Malawimonas jakobiformis, has been studied with both morphological and molecular-phylogenetic approaches, raising the spectre of interpretation errors and phylogenetic artefacts from low taxon sampling. We report a morphological and phylogenomic study of a new deep-branching malawimonad, Gefionella okellyi n. gen. n. sp. Electron microscopy revealed all canonical features of 'typical excavates', including flagellar vanes (as an opposed pair, unlike M. jakobiformis but like many metamonads) and a composite fibre. Initial phylogenomic analyses grouped malawimonads with the Amorphea-related orphan lineage Collodictyon, separate from a Metamonada+Discoba clade. However, support for this topology weakened when more sophisticated evolutionary models were used, and/or fast-evolving sites and long-branching taxa (FS/LB) were excluded. Analyses of '-FS/LB' datasets instead suggested a relationship between malawimonads and metamonads. The 'malawimonad+metamonad signal' in morphological and molecular data argues against a strict Metamonada+Discoba clade (i.e. the predominant concept of Excavata). A Metamonad+Discoba clade should therefore not be assumed when inferring deep-level evolutionary history in eukaryotes.
Collapse
Affiliation(s)
- Aaron A. Heiss
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Martin Kolisko
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Fleming Ekelund
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Matthew W. Brown
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Andrew J. Roger
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Alastair G. B. Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| |
Collapse
|
8
|
Cavalier-Smith T. Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences. PROTOPLASMA 2018; 255:297-357. [PMID: 28875267 PMCID: PMC5756292 DOI: 10.1007/s00709-017-1147-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/18/2017] [Indexed: 05/18/2023]
Abstract
In 1981 I established kingdom Chromista, distinguished from Plantae because of its more complex chloroplast-associated membrane topology and rigid tubular multipartite ciliary hairs. Plantae originated by converting a cyanobacterium to chloroplasts with Toc/Tic translocons; most evolved cell walls early, thereby losing phagotrophy. Chromists originated by enslaving a phagocytosed red alga, surrounding plastids by two extra membranes, placing them within the endomembrane system, necessitating novel protein import machineries. Early chromists retained phagotrophy, remaining naked and repeatedly reverted to heterotrophy by losing chloroplasts. Therefore, Chromista include secondary phagoheterotrophs (notably ciliates, many dinoflagellates, Opalozoa, Rhizaria, heliozoans) or walled osmotrophs (Pseudofungi, Labyrinthulea), formerly considered protozoa or fungi respectively, plus endoparasites (e.g. Sporozoa) and all chromophyte algae (other dinoflagellates, chromeroids, ochrophytes, haptophytes, cryptophytes). I discuss their origin, evolutionary diversification, and reasons for making chromists one kingdom despite highly divergent cytoskeletons and trophic modes, including improved explanations for periplastid/chloroplast protein targeting, derlin evolution, and ciliary/cytoskeletal diversification. I conjecture that transit-peptide-receptor-mediated 'endocytosis' from periplastid membranes generates periplastid vesicles that fuse with the arguably derlin-translocon-containing periplastid reticulum (putative red algal trans-Golgi network homologue; present in all chromophytes except dinoflagellates). I explain chromist origin from ancestral corticates and neokaryotes, reappraising tertiary symbiogenesis; a chromist cytoskeletal synapomorphy, a bypassing microtubule band dextral to both centrioles, favoured multiple axopodial origins. I revise chromist higher classification by transferring rhizarian subphylum Endomyxa from Cercozoa to Retaria; establishing retarian subphylum Ectoreta for Foraminifera plus Radiozoa, apicomonad subclasses, new dinozoan classes Myzodinea (grouping Colpovora gen. n., Psammosa), Endodinea, Sulcodinea, and subclass Karlodinia; and ranking heterokont Gyrista as phylum not superphylum.
Collapse
|
9
|
Heiss AA, Heiss AW, Lukacs K, Kim E. The flagellar apparatus of the glaucophyte Cyanophora cuspidata. JOURNAL OF PHYCOLOGY 2017; 53:1120-1150. [PMID: 28741699 DOI: 10.1111/jpy.12569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/12/2017] [Indexed: 05/16/2023]
Abstract
Glaucophytes are a kingdom-scale lineage of unicellular algae with uniquely underived plastids. The genus Cyanophora is of particular interest because it is the only glaucophyte that is a flagellate throughout its life cycle, making its morphology more directly comparable than other glaucophytes to other eukaryote flagellates. The ultrastructure of Cyanophora has already been studied, primarily in the 1960s and 1970s. However, the usefulness of that work has been undermined by its own limitations, subsequent misinterpretations, and a recent taxonomic revision of the genus. For example, Cyanophora's microtubular roots have been widely reported as cruciate, with rotationally symmetrical wide and thin roots, although the first ultrastructural work described it as having three wide and one narrow root. We examine Cyanophora cuspidata using scanning and transmission electron microscopy, and construct a model of its cytoskeleton using serial-section TEM. We confirm the earlier model, with asymmetric roots. We describe previously unknown and unsuspected features of its microtubular roots, including (i) a rearrangement of individual microtubules within the posterior right root, (ii) a splitting of the posterior left root into two subroots, and (iii) the convergence and termination of the narrow roots against wider ones in both the anterior and posterior subsystems of the flagellar apparatus. We also describe a large complement of nonmicrotubular components of the cytoskeleton, including a substantial connective between the posterior right root and the anterior basal body. Our work should serve as the starting point for a re-examination of both internal glaucophyte diversity and morphological evolution in eukaryotes.
Collapse
Affiliation(s)
- Aaron A Heiss
- Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
| | - Alaric W Heiss
- Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
| | - Kaleigh Lukacs
- Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
| | - Eunsoo Kim
- Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th St., New York, New York, 10024, USA
| |
Collapse
|
10
|
Heiss AA, Lee WJ, Ishida KI, Simpson AGB. Cultivation and Characterisation of New Species of Apusomonads (the Sister Group to Opisthokonts), Including Close Relatives of Thecamonas (Chelonemonas n. gen.). J Eukaryot Microbiol 2015; 62:637-49. [PMID: 25912654 DOI: 10.1111/jeu.12220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 12/15/2014] [Accepted: 12/28/2014] [Indexed: 11/29/2022]
Abstract
Apusomonads comprise an understudied and undersampled group of heterotrophic flagellates that is closely related to opisthokonts, the supergroup containing animals and fungi. We cultured representatives of a new clade of apusomonads, Chelonemonas n. gen., which is sister to marine forms of Thecamonas in SSU rRNA gene phylogenies. Scanning electron microscopy shows that members of Chelonemonas have a hexagonal patterning to their submembranous pellicle, which is not known to exist in other apusomonads. We propose that the subfamily Thecamonadinae refer to the marine Thecamonas/Chelonomonas clade. We also report two new strains of Multimonas, one of which is genetically divergent from previously described strains, and here described as a new species, Multimonas koreensis. Both strains of Multimonas have appendages on their dorsal surface that could be extrusomes, and a frilled appearance to the border of their pellicle. Explorations of taxon sampling in SSU rRNA gene phylogenies confirm the new strains' evolutionary affinities, but do not resolve relationships among the five main apusomonad clades. These phylogenies also separate the freshwater species "Thecamonas" oxoniensis from the marine members of the genus Thecamonas. The new strains described here may provide valuable genetic and morphological data for evaluating the relationships and evolution of apusomonads.
Collapse
Affiliation(s)
- Aaron A Heiss
- Department of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, New York, 10024, USA.,Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
| | - Won J Lee
- Department of Urban Environmental Engineering, Kyungnam University, Changwon, 631-701, Korea
| | - Ken-ichiro Ishida
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
| | - Alastair G B Simpson
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.,Canadian Institute for Advanced Research, Program in Integrated Microbial Diversity
| |
Collapse
|
11
|
An ancestral bacterial division system is widespread in eukaryotic mitochondria. Proc Natl Acad Sci U S A 2015; 112:10239-46. [PMID: 25831547 DOI: 10.1073/pnas.1421392112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial division initiates at the site of a contractile Z-ring composed of polymerized FtsZ. The location of the Z-ring in the cell is controlled by a system of three mutually antagonistic proteins, MinC, MinD, and MinE. Plastid division is also known to be dependent on homologs of these proteins, derived from the ancestral cyanobacterial endosymbiont that gave rise to plastids. In contrast, the mitochondria of model systems such as Saccharomyces cerevisiae, mammals, and Arabidopsis thaliana seem to have replaced the ancestral α-proteobacterial Min-based division machinery with host-derived dynamin-related proteins that form outer contractile rings. Here, we show that the mitochondrial division system of these model organisms is the exception, rather than the rule, for eukaryotes. We describe endosymbiont-derived, bacterial-like division systems comprising FtsZ and Min proteins in diverse less-studied eukaryote protistan lineages, including jakobid and heterolobosean excavates, a malawimonad, stramenopiles, amoebozoans, a breviate, and an apusomonad. For two of these taxa, the amoebozoan Dictyostelium purpureum and the jakobid Andalucia incarcerata, we confirm a mitochondrial localization of these proteins by their heterologous expression in Saccharomyces cerevisiae. The discovery of a proteobacterial-like division system in mitochondria of diverse eukaryotic lineages suggests that it was the ancestral feature of all eukaryotic mitochondria and has been supplanted by a host-derived system multiple times in distinct eukaryote lineages.
Collapse
|
12
|
Pánek T, Simpson AG, Hampl V, Čepička I. Creneis carolina gen. et sp. nov. (Heterolobosea), a Novel Marine Anaerobic Protist with Strikingly Derived Morphology and Life Cycle. Protist 2014; 165:542-67. [DOI: 10.1016/j.protis.2014.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/05/2014] [Accepted: 05/28/2014] [Indexed: 11/29/2022]
|
13
|
Yubuki N, Leander BS. Evolution of microtubule organizing centers across the tree of eukaryotes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:230-244. [PMID: 23398214 DOI: 10.1111/tpj.12145] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 05/28/2023]
Abstract
The architecture of eukaryotic cells is underpinned by complex arrrays of microtubules that stem from an organizing center, referred to as the MTOC. With few exceptions, MTOCs consist of two basal bodies that anchor flagellar axonemes and different configurations of microtubular roots. Variations in the structure of this cytoskeletal system, also referred to as the 'flagellar apparatus', reflect phylogenetic relationships and provide compelling evidence for inferring the overall tree of eukaryotes. However, reconstructions and subsequent comparisons of the flagellar apparatus are challenging, because these studies require sophisticated microscopy, spatial reasoning and detailed terminology. In an attempt to understand the unifying features of MTOCs and broad patterns of cytoskeletal homology across the tree of eukaryotes, we present a comprehensive overview of the eukaryotic flagellar apparatus within a modern molecular phylogenetic context. Specifically, we used the known cytoskeletal diversity within major groups of eukaryotes to infer the unifying features (ancestral states) for the flagellar apparatus in the Plantae, Opisthokonta, Amoebozoa, Stramenopiles, Alveolata, Rhizaria, Excavata, Cryptophyta, Haptophyta, Apusozoa, Breviata and Collodictyonidae. We then mapped these data onto the tree of eukaryotes in order to trace broad patterns of trait changes during the evolutionary history of the flagellar apparatus. This synthesis suggests that: (i) the most recent ancestor of all eukaryotes already had a complex flagellar apparatus, (ii) homologous traits associated with the flagellar apparatus have a punctate distribution across the tree of eukaryotes, and (iii) streamlining (trait losses) of the ancestral flagellar apparatus occurred several times independently in eukaryotes.
Collapse
Affiliation(s)
- Naoji Yubuki
- The Department of Botany, Beaty Biodiversity Research Centre and Museum, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada.
| | | |
Collapse
|