A New Heterolobosean Amoeboflagellate, Tetramitus dokdoensis n. sp., Isolated from a Freshwater Pond on Dokdo Island in the East Sea, Korea

Abstract

The genus Tetramitus is a representative amoeboflagellate group within the Heterolobosea, and currently contains over a dozen species. Here, a new heterolobosean amoeboflagellate was isolated from a freshwater pond on Dokdo Island, Korea. The amoebae have eruptive pseudopodia, no uroidal filament, and a nucleus with a central nucleolus. The length and width of the amoebae are 15.5-28.0 μm and 5.4-12.6 μm, respectively. The flagellates are conical, with 4 flagella of equal length (~10 μm). There is a discrete rostrum in the subapical region of the flagellate form. The cyst has thin endo- and ectocyst layers and no cyst pores. The amoeba shows slow movement at 37 °C, but does not move at 42 °C under a light microscope. Phylogenies of the 18S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 sequence show that the strain belongs to a subclade of Tetramitus that includes Tetramitus rostratus, Tetramitus waccamawensis and Tetramitus entericus, amongst others. Nonetheless, the strain is distinct from other species in both molecular phylogenetic trees. Thus the strain isolated from the Dokdo Island is proposed as a novel species, Tetramitus dokdoensis n. sp.

A New Halophilic Heterolobosean Flagellate, Aurem hypersalina gen. n. et sp. n., Closely Related to the Pleurostomum‐Tulamoeba Clade: Implications for Adaptive Radiation of Halophilic Eukaryotes

“…Heterolobosea are typically found in soil, freshwater, and marine environments, as well as in extreme habitats (Harding and Simpson ; Khwon and Park ; Pánek et al. , ; Park ; Tyml et al. ).…”

Comparative analyses of the V4 and V9 regions of 18S rDNA for the extant eukaryotic community using the Illumina platform

“…Dimensions of Mulgol are 1.4 m (width) × 1.2 m (length) × 1.7 m (depth). Because this pond has been covered with a metal lid, it has a limitation of light resources 45,48 (Fig. 1).…”

“…The light intensity was measured by light meter TES-1332A (TES Electrical Electronic Corp., Taipei, Taiwan). Additionally, because of ambient seawater and wastes from abundant seabirds, this pond contains a high concentration of nitrogen and a little dissolved salt 45,48 . The concentration of chlorophyll-a was measured by a standard protocol as described by Parsons et al 49 , and water temperature and salinity were measured using a digital salinity/temperature meter (EUTECH Salt 6 + , Thermo Fisher Scientific, Republic of Korea).…”

“…Furthermore, Heterolobosea was revealed to be the second most abundant group www.nature.com/scientificreports www.nature.com/scientificreports/ (38.6% of total read counts) in the supergroup 'Excavata' using the V9 region, but this group was not detected using the V4 region. Heterolobosea, including amoeba, amoeboflagellate, and flagellate forms, represents one of rare taxa in environmental surveys 17,30,35 , but were commonly isolated from freshwater, marine, soil, and extreme environments [36][37][38][39][40][41][42][43][44][45][46] . Pawlowski et al 17 reported that Heterolobosea comprises <1% of total reads using NGS technology with only the V9 region.…”

Morphology and Phylogenetic Analyses of Three Novel Naegleria Isolated from Freshwaters on Jeju Island, Korea, During the Winter Period

“…Free‐living amoeba (FLA) are a highly diverse group, and are commonly thought of as entities in freshwater, marine, soil, and extreme hypersaline environments (Page , ; Park , ; Park et al. , ; Rogerson and Patterson ).…”