The morphologies of the three freshwater stentorid ciliates in Korea, Stentor coeruleus (Pallas, 1766); Stentor muelleri Ehrenberg, 1831, and Stentor tartari Murthy Bai, 1974, were investigated based on live observations and protargol impregnation. The Korean population of S. tartari exhibits the following characteristics: body size 200-355 × 85-135 µm in vivo, 62-106 somatic kineties, 8-13 peristomial kineties, 110-180 adoral membranelles, mostly two macronuclear nodules and 5-18 micronuclei, reddish and colorless cortical granules and the presence of symbiotic algae. We identified S. tartari based on unique characteristics compared to close congeners. Korean populations of S. coeruleus and S. muelleri are congruent with previously described populations in most aspects of their morphologies. Here, for the first time, we report molecular gene sequence information for S. tartari. Small subunit (SSU) rRNA gene sequence-based phylogeny indicates that S. tartari, which has multiple macronuclei, forms a monophyletic group with other Stentor species having a single macronucleus. Our findings based on morphology and SSU rRNA gene sequence information corroborate the hypothesis that the elongated macronucleus evolved from the compact single or multi macronucleus state.
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http://dx.doi.org/10.11646/zootaxa.4732.3.6 | DOI Listing |
Sci China Life Sci
January 2025
Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
Whole-genome duplication (WGD) events are widespread across eukaryotes and have played a significant role in moulding the genetic architectures of diverse organisms. In the present study, the newly sequenced genome of a giant ciliated protist, Stentor roeselii, provides an opportunity for the analysis of the collinearity and retention of reciprocal best-hit genes between two Stentor species. As a main result, we have unveiled a previously undetected ancient WGD event shaping the genome of its congener, Stentor coeruleus, a model protist used in cytological and evolutionary studies.
View Article and Find Full Text PDFbioRxiv
August 2024
University of California, San Francisco.
The study of evolution at the cellular level traditionally has focused on the evolution of metabolic pathways, endomembrane systems, and genomes, but there has been increasing interest in evolution of more complex cellular structures and behaviors, particularly in the eukaryotes. Ciliates have major advantages for such studies due to their easily visible surface patterning and their dramatic and complex behaviors that can be easily analyzed. Among the ciliates, the genus epitomizes the features that are useful for studying evolution: they are widespread in freshwater environments, easy to visualize because of their large size, and capable of complex behaviors such as learning, decision-making, and phototaxis.
View Article and Find Full Text PDFSci Rep
April 2024
Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.
Ciliates are powerful unicellular model organisms that have been used to elucidate fundamental biological processes. However, the high motility of ciliates presents a major challenge in studies using live-cell microscopy and microsurgery. While various immobilization methods have been developed, they are physiologically disruptive to the cell and incompatible with microscopy and/or microsurgery.
View Article and Find Full Text PDFbioRxiv
February 2024
Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.
Ciliates are powerful unicellular model organisms that have been used to elucidate fundamental biological processes. However, the high motility of ciliates presents a major challenge in studies using live-cell microscopy and microsurgery. While various immobilization methods have been developed, they are physiologically disruptive to the cell and incompatible with microscopy and/or microsurgery.
View Article and Find Full Text PDFInt J Mol Sci
September 2022
Laboratory of Molecular Cell Biology, Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
is a ciliate known for its regenerative ability. Recent genome sequencing reveals that its spliceosomal introns are exceptionally small. We wondered whether the multimegadalton spliceosome has any unique characteristics for removal of the tiny introns.
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