Study On The Molecular Phylogeny Of Some Groups In Sessile Peritrichida(Protozoa,Ciliophora)

Ciliates as the most morphorlogically complex and highly differentiated taxon among monocellular eukaryotes belong to Protozoa,Ciliophora.Ciliated protozoa is an important part of microbial food web and plays an significant role in energy transfer within the ecosystem.As a kind of favorable model organism,ciliate has been wildly used into scientific research fields of cell biology,molecular biology and molecular systematic.Especially in the biogenesis and evolution,ciliate has unique research status.In this work,sessile peritrichs were used as research object.We made studies on molecular systematic and analyze phylogenetic relationships of sessile peritrichs by sequencing more genes(SSU rDNA,LSU rDNA,ITS1-5.8S-ITS2).The main results showed as following:1.We get 68 new sequences,including 31 SSU rDNA,21 ITS1-5.8S-ITS2 and 16 LSU rDNA,involved in 32 species,6 genera and 4 families.All sequences had been submitted to GenBank database and could be released after papers published.2.A novel species was established by live observations,silver staining method and molecular phylogenetic analysis.The main summaries as following:1.The phylogenetic analyses suggest that:(1)In Zoothamniidae,Zoothamnium is ancestral,with fully distributed spasmoneme as plesiomorphy;(2)Myoschiston and Epistylis is derived from Zoothamnium by insufficiently expression or non-expression of the spasmoneme gene,and Zoothamnopsis is also derived from Zoothamnium;(3)Epistylididae is polyphyletic,and its third clade should be the ancestral type of sessile peritrich;(4)Vaginicolidae is monophyletic,and it should be a kind of the ancestral types of sessile peritrich;(5)For a clearer phylogeny of peritrichs,a intact database of multigene sequences is needed.2.Cothurnia salina n.sp.: body elongated columnar,in vivo 80–98 × 12–19 ?m;lorica barrel-shaped,with aboral part heavily thickened;stalk extremely short,with approximately ? of its length within the lorica;macronucleus wormlike,longitudinally oriented;single contractile vacuole ventrally located;pellicle with conspicuous parallel transverse striations,62–73 from aboral trochal band to peristome and 32–38 from aboral trochal band to scopula;infundibular polykinety 3(P3)consisting of two ciliary rows,which are equal length,parallel to each other and terminate adstomally between P1 and P2.Hypersaline habitat.This work maily classified phylogeny of some sessile peritrichs group;and improved the molecular database in the GenBank.In addition,morphologically study of a new species of Cothurnia was also included.