A description of Apocarchesium rosettum n. gen., n. sp. and a redescription of Ophrydium eichornii , two freshwater peritrichous ciliates from Japan

et al. 2011

Journal of Morphology

The process of stomatogenesis in peritrich ciliates is still incompletely understood. Previous studies on the stomatogenesis of four species of peritrichs, Telotrochidium sp., Carchesium polypinum, Opercularia coarctata, and Astylozoon pyriforme conflict with one another in some cases and omit details of events in others. We described the entire process of stomatogenesis in the peritrich ciliate Campanella umbellaria (C. umbellaria) using an improved method of staining with protargol. Our results disagree with some previous studies with regard to the formation of some rudimentary structures, reorganization of the parental haplokinety, formation of new germinal rows, and separation of daughter oral complexes. The pattern of stomatogenesis characteristic of peritrichs is compared to the stomatogenetic patterns of three other oligohymenophorean subclasses and a hypothesis about the evolution of stomatogenesis in the class Oligohymenophorea is offered. Details of stomatogenesis need to be described and verified in a greater variety of peritrichs to clarify possible differences between taxa and make it possible to relate stomatogenesis to evolution within the subclass Peritrichia. Ultrastructural studies are the next step in description of morphogenetic processes in peritrichs, and characteristics of C. umbellaria make it a useful model for this work.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new interpretation of stomatogenesis in a peritrich ciliate: Using Campanella umbellaria as a model system

Wang

Shi

et al. 2011

Journal of Morphology

“…Members of the genus Apocarchesium (Fig. 1a, b) are colonial, like members of the genus Carchesium, but form colonies that consist of only a cluster of unbranched zooids at the tip of the primary stalk (Ji & Kusuoka, 2009). …”

Section: Introductionmentioning

confidence: 99%

Molecular phylogeny of the family Vorticellidae (Ciliophora, Peritrichia) using combined datasets with a special emphasis on the three morphologically similar genera Carchesium, Epicarchesium and Apocarchesium

Sun

International Journal of Systematic and Evolutionary Microbiology

et al. 2011

Self Cite

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.

“…peristomial [Pk] and infundibular polykineties [P1, P2, P3], haplokinety [Hk], germinal kinety [Gk], filamentous reticulum [FR]), but the lengths, positions, and other structural details of these components differ among taxa, providing useful characteristics for classification (Clamp ; Clamp and Bradbury ; Clamp and Coats ; Clamp and Kane ; Foissner et al. ; Ji and Kusuoka ; Ji and Song ; Ji et al. , , , ; Norf and Foissner ; Peng et al.…”

Section: Discussionmentioning

confidence: 99%

Evolution of Variations in the Common Pattern of Stomatogenesis in Peritrich Ciliates: Evidence from a Comparative Study Including a New Description of Stomatogenesis in Pseudepistylis songi Peng et al.,

Wang

J Eukaryotic Microbiology

Shi

et al. 2012

The stomatogenesis of peritrich ciliates is an important developmental process but has been studied relatively little for such a large, diverse taxon. Complex oral structures and an inability of staining techniques to reveal them clearly have been the major factors hindering investigation of this process. In the present study, an improved method of staining with protargol was used to investigate the entire process of stomatogenesis in a large, colonial species of peritrich, Pseudepistylis songi, and to compare it to descriptions of stomatogenesis in several other species. We found that P. songi and other peritrichs have the same general type of ophryobuccokinetal stomatogenesis, with the parental oral complex being inherited by one daughter and the new oral complex by the other daughter; however, some differences between individual taxa appear to have arisen in the course of evolution. Reorganization of the entire germinal kinety (Gk) to form the germinal anlage may be plesiomorphic, with restriction of reorganization to its abstomal part being apomorphic. Development of the entire new haplokinety of one daughter cell (2Hk) from the germinal band or its homologue also appears to be plesiomorphic, with development of peristomial and infundibular parts of 2Hk from separate rudiments being apomorphic. Furthermore, development of the new Gk of the parental oral complex (1Gk) from the entire infundibular part of the parental haplokinety (1Hk) may be plesiomorphic, and development from just the abstomal part may be apomorphic. Finally, development of the Gk of the new oral complex (2Gk) from residual kinetosomes of the germinal band appears to be plesiomorphic.