Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers ...Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.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
基金The National Natural Science Foundation of China under contract Nos 30570236,U0633006,40506033 and 40676076the Program for New Century Excellent Talents in Universities of China under contract No. NCET05-0595
文摘Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.
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.
