The evolutionary relationships of seven spirotrichous ciliates (3 stichotrichs: Oxytricha saltans, O. Ferruginea, Stylonychia mytilus; 4 hypotrichs: Uronychia transfuga, Diophrys appendiculata, Aspidisca steini, Euplo...The evolutionary relationships of seven spirotrichous ciliates (3 stichotrichs: Oxytricha saltans, O. Ferruginea, Stylonychia mytilus; 4 hypotrichs: Uronychia transfuga, Diophrys appendiculata, Aspidisca steini, Euplotes vannus ) inferred from the SSrRNA (small subunit rRNA) gene sequences and the polymorphic patterns of RAPD (random amplified polymorphic DNA) and ARDRA (amplified ribosomal DNA restriction analyses) fingerprinting are constructed. Compared with that of morphometric characters, the dendrograms from SSrRNA gene using three different calculation methods (distance matrix, maximum parsimony, and UPGMA) agree with the morphological division into two clades, Oxytricha Stylonychia and Uronychia Diophrys Aspidisca Euplotes, though the branching orders within the hypotrichous ciliates are slightly different from morphometric analyses.展开更多
The complete small subunit rRNA （SSrRNA） gene sequence of a marine ciliate, Dysteria derouxi Gong and Song, 2004, was determined to be of 1 708 nucleotides. The phylogenetic position of this species within the class...The complete small subunit rRNA （SSrRNA） gene sequence of a marine ciliate, Dysteria derouxi Gong and Song, 2004, was determined to be of 1 708 nucleotides. The phylogenetic position of this species within the class Phyllopharyngea was deduced using distance matrix, maximum parsimony and maximum likelihood methods. Dysteria derouxi, together with other available ciliates of the class Phyllopharyngea, forms a monophyletic clade with strong bootstrap support in the distance matrix, maximum parsimony and likelihood tree construction methods, while the dysterids are, as a monophyletic group, phylogenetically close to the clade of chlamydodontids [values of 100% LS（least-squares）, 100% NJ（neighabor-joining）]. In addition, the trees indicate that dysteriids may be a higher or specialized group within the class, which corresponds well to the morphology and infraciliature.展开更多
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha ...In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha sp.,and A.manca,were compared and analyzed using ITS2 secondary structures,ITS1-5.8S-ITS2 region and SSrRNA gene sequences.The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced,and they shared sequence identities ranging from 68.0% to 90.1%,while two populations of Anteholosticha sp.differed in three nucleotides（sequence identity 99.8%）.There were several minor differences among ITS2 secondary structures of these species,while two populations of Anteholosticha sp.had the identical secondary structure.Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms（Neighbor-Joining,Maximum Parsimony and Bayesian） revealed similar topologies.The results show that：（1） Holosticha bradburyae and H.diademata firmly clustered together with strong bootstrap supports,forming a sister clade with Anteholosticha sp.,（2） Anteholosticha appeared to be a paraphyletic assemblage,in which the morphotype A.manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp.Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha,nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.展开更多
To separate and redefine the ambiguous Holosticha-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera, Holosticha heterofoissneri, Anteholosticha sp. pop1, ...To separate and redefine the ambiguous Holosticha-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera, Holosticha heterofoissneri, Anteholosticha sp. pop1, Anteholosticha sp. pop2, A. manca, A. gracilis and Nothoholosticha fasciola, were analyzed using 12 restriction enzymes on the basis of amplified ribosomal DNA restriction analysis. Nine of the 12 enzymes could digest the DNA products, four (Hinf I, Hind III, Msp I, Taq I) yielded species-specific restriction patterns, and Hind III and Taq I produced different patterns for two Anteholosticha sp. populations. Distinctly different restriction digestion haplotypes and similarity indices can be used to separate the species. The secondary structures of the five species were predicted based on the ITS2 transcripts and there were several minor differences among species, while two Anteholosticha sp. populations were identical. In addition, phylogenies based on the SSrRNA gene sequences were reconstructed using multiple algorithms, which grouped them generally into four clades, and exhibited that the genus Anteholosticha should be a convergent assemblage. The fact that Holosticha species clustered with the oligotrichs and choreotrichs, though with very low support values, indicated that the topology may be very divergent and unreliable when the number of sequence data used in the analyses is too low.展开更多
The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent...The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.展开更多
基金SupportedbytheNaturalScienceFoundationofChina (No .3 9970 0 98) theCheungKongScholarshipProgrammeandaresearchgrantbytheEducationalMinistryofChina (No .990 77)
文摘The evolutionary relationships of seven spirotrichous ciliates (3 stichotrichs: Oxytricha saltans, O. Ferruginea, Stylonychia mytilus; 4 hypotrichs: Uronychia transfuga, Diophrys appendiculata, Aspidisca steini, Euplotes vannus ) inferred from the SSrRNA (small subunit rRNA) gene sequences and the polymorphic patterns of RAPD (random amplified polymorphic DNA) and ARDRA (amplified ribosomal DNA restriction analyses) fingerprinting are constructed. Compared with that of morphometric characters, the dendrograms from SSrRNA gene using three different calculation methods (distance matrix, maximum parsimony, and UPGMA) agree with the morphological division into two clades, Oxytricha Stylonychia and Uronychia Diophrys Aspidisca Euplotes, though the branching orders within the hypotrichous ciliates are slightly different from morphometric analyses.
文摘The complete small subunit rRNA （SSrRNA） gene sequence of a marine ciliate, Dysteria derouxi Gong and Song, 2004, was determined to be of 1 708 nucleotides. The phylogenetic position of this species within the class Phyllopharyngea was deduced using distance matrix, maximum parsimony and maximum likelihood methods. Dysteria derouxi, together with other available ciliates of the class Phyllopharyngea, forms a monophyletic clade with strong bootstrap support in the distance matrix, maximum parsimony and likelihood tree construction methods, while the dysterids are, as a monophyletic group, phylogenetically close to the clade of chlamydodontids [values of 100% LS（least-squares）, 100% NJ（neighabor-joining）]. In addition, the trees indicate that dysteriids may be a higher or specialized group within the class, which corresponds well to the morphology and infraciliature.
基金The Natural Science Foundation of China under contract No. 30870264the Center of Excellence in Biodiversity,King Saud University,Saudi Arabia
文摘In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha sp.,and A.manca,were compared and analyzed using ITS2 secondary structures,ITS1-5.8S-ITS2 region and SSrRNA gene sequences.The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced,and they shared sequence identities ranging from 68.0% to 90.1%,while two populations of Anteholosticha sp.differed in three nucleotides（sequence identity 99.8%）.There were several minor differences among ITS2 secondary structures of these species,while two populations of Anteholosticha sp.had the identical secondary structure.Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms（Neighbor-Joining,Maximum Parsimony and Bayesian） revealed similar topologies.The results show that：（1） Holosticha bradburyae and H.diademata firmly clustered together with strong bootstrap supports,forming a sister clade with Anteholosticha sp.,（2） Anteholosticha appeared to be a paraphyletic assemblage,in which the morphotype A.manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp.Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha,nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.
基金Supported by the Natural Science Foundation of China (Nos. 30870264 and 40976099)the Center of Excellence in Biodiversity, King Saud University
文摘To separate and redefine the ambiguous Holosticha-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera, Holosticha heterofoissneri, Anteholosticha sp. pop1, Anteholosticha sp. pop2, A. manca, A. gracilis and Nothoholosticha fasciola, were analyzed using 12 restriction enzymes on the basis of amplified ribosomal DNA restriction analysis. Nine of the 12 enzymes could digest the DNA products, four (Hinf I, Hind III, Msp I, Taq I) yielded species-specific restriction patterns, and Hind III and Taq I produced different patterns for two Anteholosticha sp. populations. Distinctly different restriction digestion haplotypes and similarity indices can be used to separate the species. The secondary structures of the five species were predicted based on the ITS2 transcripts and there were several minor differences among species, while two Anteholosticha sp. populations were identical. In addition, phylogenies based on the SSrRNA gene sequences were reconstructed using multiple algorithms, which grouped them generally into four clades, and exhibited that the genus Anteholosticha should be a convergent assemblage. The fact that Holosticha species clustered with the oligotrichs and choreotrichs, though with very low support values, indicated that the topology may be very divergent and unreliable when the number of sequence data used in the analyses is too low.
基金Supported by the National Natural Science Foundation of China (No. 30870264, 40976075)a grant from the Center of Excellence in Biodiversity, King Saud Universitya Marie Curie Incoming International Fellowship within the 7th European Community Framework Programme
文摘The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.
