Researchers at University of Tsukuba discovered a new species of unicellular organism, Glissandra oviformis, belonging to the CRuMs clade in a sample collected from a marine lake in the Republic of Palau. Electron microscopic observation revealed a few common morphological characteristics between G. oviformis and other CRuMs members.

Tsukuba, Japan—Protists (eukaryotes, excluding animals, land plants, and fungi) comprise the bulk of the eukaryotic phylogenetic tree, making their diversity essential to understanding eukaryotic evolution. Nevertheless, they remain understudied due to their microscopic size and difficulty in cultivation.

Researchers at the University of Tsukuba successfully established a culture strain of a protist from a seaweed sample collected from a marine lake in the Republic of Palau. Microscopic observations revealed that this organism is a new species of the genus Glissandra, whose phylogenetic position was uncertain, and the researchers named it as "Glissandra oviformis." Large-scale molecular phylogenetic analysis based on 340 protein sequences revealed that G. oviformis is a novel lineage within CRuMs, one of the major eukaryotic lineages. To elucidate the evolution of morphological traits within CRuMs, the researchers examined G. ovbiformis under an electron microscope, which revealed that the sheet-like structure lining the cell membrane and the structure of the base of the flagella are common with those of CRuMs members.

These observations revealed shared characteristics among CRuMs members. The rediscovery, culturing, and detailed investigation of protists with uncertain phylogenetic positions could be an essential approach to understanding the evolution of eukaryotic organisms.

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This work was supported by JSPS KAKENHI Grant Numbers 13J00587 (awarded to T.S.), 23405013 (awarded to K.I.), 23K27226 and BPI06050 (awarded to Y.I.).

Original Paper

Title of original paper:

Glissandra oviformis n. sp.: a novel predatory flagellate illuminates the character evolution within the eukaryotic clade CRuMs

Journal:

Open Biology

DOI:

10.1098/rsob.250057

Correspondence

Assistant Professor SHIRATORI Takashi
Institute of Life and Environmental Sciences, University of Tsukuba

Related Link

Institute of Life and Environmental Sciences