scholarly journals Phylogenetic position of Multicilia marina and the evolution of Amoebozoa

2006 ◽  
Vol 56 (6) ◽  
pp. 1449-1458 ◽  
Author(s):  
Sergey I. Nikolaev ◽  
Cédric Berney ◽  
Nikolai B. Petrov ◽  
Alexandre P. Mylnikov ◽  
José F. Fahrni ◽  
...  

Recent molecular phylogenetic studies have led to the erection of the phylum Amoebozoa, uniting naked and testate lobose amoebae, the mycetozoan slime moulds and amitochondriate amoeboid protists (Archamoebae). Molecular data together with ultrastructural evidence have suggested a close relationship between Mycetozoa and Archamoebae, classified together in the Conosea, which was named after the cone of microtubules that, when present, is characteristic of their kinetids. However, the relationships of conoseans to other amoebozoans remain unclear. Here, we obtained the complete small-subunit (SSU) rRNA gene sequence (2746 bp) of the enigmatic, multiflagellated protist Multicilia marina, which has formerly been classified either in a distinct phylum, Multiflagellata, or among lobose amoebae. Our study clearly shows that Multicilia marina belongs to the Amoebozoa. Phylogenetic analyses including 60 amoebozoan SSU rRNA gene sequences revealed that Multicilia marina branches at the base of the Conosea, together with another flagellated amoebozoan, Phalansterium solitarium, as well as with Gephyramoeba sp., Filamoeba nolandi and two unidentified amoebae. This is the first report showing strong support for a clade containing all flagellated amoebozoans and we discuss the position of the root of the phylum Amoebozoa in the light of this result.

2015 ◽  
Vol 65 (Pt_12) ◽  
pp. 4323-4334 ◽  
Author(s):  
Zhishuai Qu ◽  
Hongbo Pan ◽  
Khaled A. S. Al-Rasheid ◽  
Xiaozhong Hu ◽  
Shan Gao

Three cyrtophorian ciliates isolated from brackish biotopes in China, Pseudochilodonopsis quadrivacuolata sp. nov., Pseudochilodonopsis fluviatilis Foissner, 1988 and Pseudochilodonopsis mutabilis Foissner, 1981, were investigated using living observation and protargol-staining methods. P. quadrivacuolata sp. nov. can be characterized as follows: cell size 50–70 × 30–40 μm in vivo; body oval with posterior end rounded; four tetragonally positioned contractile vacuoles; 12–15 nematodesmal rods; five right and six left somatic kineties; terminal fragment positioned apically on dorsal side, consisting of 11–14 basal bodies; four or five fragments in preoral kinety. P. fluviatilis and P. mutabilis were generally consistent with previous descriptions. In addition, a brief revision and a key to Pseudochilodonopsis are presented. The small-subunit (SSU) rRNA gene was also sequenced to support the identification of these species. Phylogenetic analyses based on molecular data indicate that the genera Pseudochilodonopsis and Chilodonella are closely related and both are well outlined; that is, all known congeners for which SSU rRNA gene sequence data are available group together, forming the core part of the family Chilodonellidae.


Author(s):  
Ran Li ◽  
Wenbao Zhuang ◽  
Congcong Wang ◽  
Hamed El-Serehy ◽  
Saleh A. Al-Farraj ◽  
...  

The morphology and molecular phylogeny of Plagiopyla ovata Kahl, 1931, a poorly known anaerobic ciliate, were investigated based on a population isolated from sand samples collected from the Yellow Sea coast at Qingdao, PR China. Details of the oral ciliature are documented for the first time to our knowledge and an improved species diagnosis is given. The small subunit ribosomal RNA (SSU rRNA) gene was newly sequenced and phylogenetic analyses revealed that P. ovata clusters within the monophyletic family Plagiopylidae. However, evolutionary relationships within both the family Plagiopylidae and the genus Plagiopyla remain obscure owing to undersampling, the lack of sequence data from known species and low nodal support or unstable topologies in gene trees. A key to the identification of the species of the genus Plagiopyla with validly published names is also supplied.


2005 ◽  
Vol 55 (6) ◽  
pp. 2595-2604 ◽  
Author(s):  
Dag Klaveness ◽  
Kamran Shalchian-Tabrizi ◽  
Helge Abildhauge Thomsen ◽  
Wenche Eikrem ◽  
Kjetill S. Jakobsen

Telonema is a widely distributed group of phagotrophic flagellates with two known members. In this study, the structural identity and molecular phylogeny of Telonema antarcticum was investigated and a valid description is proposed. Molecular phylogeny was studied using small-subunit rRNA (SSU rRNA) gene sequences. The pear-shaped cell had two subequal flagella that emerged laterally on the truncated antapical tail. One flagellum had tripartite hairs. The cell was naked, but had subsurface vesicles containing angular paracrystalline bodies of an unknown nature. A unique complex cytoskeletal structure, the subcortical lamina, was found to be an important functional and taxonomic feature of the genus. Telonema has an antero-ventral depression where food particles are ingested and then transferred to a conspicuous anterior food vacuole. The molecular phylogeny inferred from the SSU rRNA gene sequence suggested that Telonema represents an isolated and deep branch among the tubulocristate protists.


2012 ◽  
Vol 62 (Pt_11) ◽  
pp. 2757-2773 ◽  
Author(s):  
Xiaozhong Hu ◽  
Jie Huang ◽  
Alan Warren

The morphology, infraciliature and molecular phylogeny of two marine ciliated protozoans, Diophrys blakeneyensis spec. nov. and Diophrys oligothrix Borror, 1965, isolated from British salt marshes, were investigated using microscopic observations of live and protargol-impregnated specimens, and by small subunit (SSU) rRNA gene sequence analysis. Diophrys blakeneyensis spec. nov. is characterized as follows: cell oval to rectangular in outline; size variable, approximately 60–180 × 30–80 µm in vivo; adoral zone comprising about 45 membranelles; usually five frontal, two ventral, five transverse, two left marginal and three caudal cirri; five dorsal kineties with more than 10 dikinetids each; 7–23 spherical to ellipsoid macronuclear nodules in a ring-like pattern; marine biotope. The population of Diophrys oligothrix described here corresponds well with previous populations in terms of its general morphology and ciliary pattern, in particular the continuous ciliary rows on the dorsal side with loosely arranged cilia. The main differences between the present and previously reported populations are the broader buccal field and greater number of dorsal kineties in the present population, both of which are regarded as population-dependent features. Phylogenetic analyses based on SSU rRNA gene sequence data demonstrate that Diophrys blakeneyensis is most closely related to Diophrys oligothrix, and both organisms cluster with two congeners with high bootstrap support within a larger group that contain the core species of the Diophrys-complex. Cladistic analysis based on morphological and morphogenetic data broadly agree with the SSU rRNA gene sequence phylogeny. Both analyses suggest that the genus Diophrys may be polyphyletic.


2013 ◽  
Vol 63 (Pt_3) ◽  
pp. 1179-1191 ◽  
Author(s):  
Wen Song ◽  
Jiamei Li ◽  
Weiwei Liu ◽  
Jiamei Jiang ◽  
Khaled A. S. Al- Rasheid ◽  
...  

Three oligotrich ciliates, Apostrombidium parakielum spec. nov., Novistrombidium apsheronicum (Alekperov & Asadullayeva, 1997) Agatha, 2003 and Novistrombidium testaceum (Anigstein, 1914) Song & Bradbury, 1998 were collected from the coastal waters of China and their morphology and small-subunit rRNA (SSU rRNA) gene sequences were studied. The novel species can be recognized by the combination of its obconical body shape, 14–16 anterior and 6–8 ventral membranelles, somatic kinety in three parts and conspicuously long dorsal cilia. Based on the data obtained for this novel species, an improved diagnosis of the genus Apostrombidium is supplied. Descriptions of the population of N. apsheronicum and N. testaceum collected in this study are also provided and compared with the existing descriptions. In addition, the phylogenetic positions of these three species are inferred from their SSU rRNA gene sequence data. The results indicate that the genus Apostrombidium, the systematics of which has not previously been discussed using molecular information, clusters with Varistrombidium kielum and Omegastrombidium elegans, whereas N. testaceum and N. apsheronicum form a single clade.


2013 ◽  
Vol 63 (Pt_9) ◽  
pp. 3506-3514 ◽  
Author(s):  
Ying Yan ◽  
Yuan Xu ◽  
Zhenzhen Yi ◽  
Alan Warren

Three trachelocercid ciliates, Kovalevaia sulcata (Kovaleva, 1966) Foissner, 1997, Trachelocerca sagitta (Müller, 1786) Ehrenberg, 1840 and Trachelocerca ditis (Wright, 1982) Foissner, 1996, isolated from two coastal habitats at Qingdao, China, were investigated using live observation and silver impregnation methods. Data on their infraciliature and morphology are supplied. The small subunit rRNA (SSU rRNA) genes of K. sulcata and Trachelocerca sagitta were sequenced for the first time. Phylogenetic analyses based on SSU rRNA gene sequence data indicate that both organisms, and the previously sequenced Trachelocerca ditis, are located within the trachelocercid assemblage and that K. sulcata is sister to an unidentified taxon forming a clade that is basal to the core trachelocercids.


2012 ◽  
Vol 57 (4) ◽  
Author(s):  
B. Nath ◽  
S. Gupta ◽  
A. Bajpai

AbstractThe life cycle, spore morphology, pathogenicity, tissue specificity, mode of transmission and small subunit rRNA (SSU-rRNA) gene sequence analysis of the five new microsporidian isolates viz., NIWB-11bp, NIWB-12n, NIWB-13md, NIWB-14b and NIWB-15mb identified from the silkworm, Bombyx mori have been studied along with type species, NIK-1s_mys. The life cycle of the microsporidians identified exhibited the sequential developmental cycles that are similar to the general developmental cycle of the genus, Nosema. The spores showed considerable variations in their shape, length and width. The pathogenicity observed was dose-dependent and differed from each of the microsporidian isolates; the NIWB-15mb was found to be more virulent than other isolates. All of the microsporidians were found to infect most of the tissues examined and showed gonadal infection and transovarial transmission in the infected silkworms. SSU-rRNA sequence based phylogenetic tree placed NIWB-14b, NIWB-12n and NIWB-11bp in a separate branch along with other Nosema species and Nosema bombycis; while NIWB-15mb and NIWB-13md together formed another cluster along with other Nosema species. NIK-1s_mys revealed a signature sequence similar to standard type species, N. bombycis, indicating that NIK-1s_mys is similar to N. bombycis. Based on phylogenetic relationships, branch length information based on genetic distance and nucleotide differences, we conclude that the microsporidian isolates identified are distinctly different from the other known species and belonging to the genus, Nosema. This SSU-rRNA gene sequence analysis method is found to be more useful approach in detecting different and closely related microsporidians of this economically important domestic insect.


2011 ◽  
Vol 61 (4) ◽  
pp. 1001-1010 ◽  
Author(s):  
Ping Sun ◽  
John C. Clamp ◽  
Dapeng Xu ◽  
Yasushi Kusuoka ◽  
Manabu Hori

Little is known about the phylogeny of the family Vorticellidae at the generic level because few comprehensive analyses of molecular phylogenetic relationships between members of this group have, so far, been done. As a result, the phylogenetic positions of some genera that were based originally on morphological analyses remain controversial. In the present study, we performed phylogenetic analyses of vorticellids based on the sequence of the small-subunit (SSU) rRNA gene, including one species of the genus Apocarchesium, for which no sequence has previously been reported. Phylogenetic trees were reconstructed with SSU rRNA gene sequences by using four different methods (Bayesian analysis, maximum-likelihood, neighbour-joining and maximum-parsimony) and had a consistent branching pattern. Members of the genera Vorticella (except V. microstoma) and Carchesium formed a clearly defined, well supported clade that was divergent from the clade comprising members of the genera Pseudovorticella and Epicarchesium, suggesting that the differences in the silverline system (transverse vs reticulate) among vorticellids may be the result of genuine evolutionary divergence. Members of the newly established genus Apocarchesium clustered within the family Vorticellidae basal to the clade containing members of the genera Pseudovorticella and Epicarchesium and were distinct from members of the genus Carchesium, supporting the validity of Apocarchesium as a novel genus. Additional phylogenetic analyses of 21 strains representing seven genera from the families Vorticellidae and Zoothamniidae were performed with single datasets (ITS1–5.8S–ITS2, ITS2 alone) and combined datasets (SSU rRNA+ITS1–5.8S–ITS2, SSU rRNA+ITS2) to explore further the phylogenetic relationship between the three morphologically similar genera Carchesium, Epicarchesium and Apocarchesium, using characteristics not included in previous analyses. The phylogenetic trees reconstructed with combined datasets were more robust and therefore more reliable than those based on single datasets and supported the results of trees based on SSU rRNA sequences.


Parasitology ◽  
2019 ◽  
Vol 146 (14) ◽  
pp. 1719-1724 ◽  
Author(s):  
Vasana Jinatham ◽  
Siam Popluechai ◽  
C. Graham Clark ◽  
Eleni Gentekaki

AbstractThe genusEntamoebacomprises mostly gut parasites and commensals of invertebrate and vertebrate animals including humans. Herein, we report a new species ofEntamoebaisolated from the gut of Asian swamp eels (Monopterus albus) in northern Thailand. Morphologically, the trophozoite is elongated and has a single prominent pseudopodium with no clear uroid. The trophozoite is actively motile, 30–50µm in length and 9–13µm in width. Observed cysts were uninucleate, ranging in size from 10 to 17.5µm in diameter. Chromatin forms a fine, even lining along the inner nuclear membrane. Fine radial spokes join the karyosome to peripheral chromatin. Size, host and nucleus morphology set our organism apart from other members of the genus reported from fish. The SSU rRNA gene sequences of the new isolates are the first molecular data of anEntamoebaspecies from fish. Phylogenetic analysis places the new organism as sister toEntamoeba invadens. Based on the distinct morphology and SSU rRNA gene sequence we describe it as a new species,Entamoeba chiangraiensis.


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