New data on the species diversity and morphology of centrohelid heliozoans in freshwater, marine, and soil habitats of Ukraine were obtained. Cell coverings (scales and spicules) were observed using scanning and transmission electron microscopy. Eighteen species from seven genera of centrohelids and unidentifiable Heterophrys-like organisms were revealed. The micrographs and detailed morphological descriptions of observed species and their comparison with previously found centrohelids are provided. A new genus and three new species Acanthocystis tyrasiana sp. nov., Pterocystis borysthenica sp. nov., and Khitsovia mutabilis gen. et sp. nov. were described. Molecular phylogenetic analyses based on 18S rRNA sequences, obtained for three strains, expand our knowledge on the diversity and evolution of centrohelids within the Pterista clade. The novel data on the morphology of studied scales supplement available information on the intraspecific variability of centrohelid heliozoans.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.ejop.2022.125916 | DOI Listing |
Eur J Protistol
June 2024
Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, 152742 Borok, Russia.
A new species of centrohelid heliozoans, Pterocystis polycristalepis sp. nov. (Pterocystidae), was examined using light and electron microscopy.
View Article and Find Full Text PDFRaphidocystis marginata (Siemensma, 1981), Raineriophrys echinata (Rainer, 1968), and Pterocystis fortesca (Nicholls, 1983) are heliozoan protists, have been recorded only in a few localities in Europe, and considered to be rare species. These centrohelid heliozoans have been reported for the first time in Ukrainian Polissia, and we provide their morphological descriptions with new morphometric data of exoskeleton (periplast) based on Ukrainian material. The diagnostic morphological characters are illustrated by light and scanning electron microscope photographs.
View Article and Find Full Text PDFEur J Protistol
August 2023
Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk 664033, Russia.
Maintaining high levels of biological diversity in various ecosystems is necessary for stable functioning of the Earth's biosphere. The article describes diversity and ecology of heterotrophic siliceous protists - rotosphaerids, colourless free-living thaumatomonad flagellates, and centrohelid heliozoans - in Arctic waters located of Asian Russia. Samples were collected in the mouths of the Olenyok, Yana, Indigirka, Kolyma Rivers - and small freshwater ponds near Settlement of Tiksi in Yakutia.
View Article and Find Full Text PDFEur J Protistol
April 2023
Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan. Electronic address:
The centrohelid heliozoan Raphidocystis contractilis has hundreds of small scales on the surface of the cell body. To understand the biological functions of the scales, comparative examinations were conducted between wild-type and scale-deficient strains that has naturally lost scales after long-term cultivation. The scale-deficient strain exhibited decreased adhesion to the substratum and had a lower sedimentation rate in water than the wild-type strain, suggesting that the scale may have the ability to attach quickly and strongly to the substratum.
View Article and Find Full Text PDFJ Eukaryot Microbiol
March 2023
Laboratory of Cell Physiology, Department of Science Education, Faculty of Education, Okayama University, Okayama, Japan.
The centrohelid heliozoan Raphidocystis contractilis has many radiating axopodia, each containing axopodial microtubules. The axopodia show rapid contraction at nearly a video rate (30 frames per second) in response to mechanical stimuli. The axopodial contraction is accompanied by cytoskeletal microtubule depolymerization, but the molecular mechanism of this phenomenon has not been elucidated.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!