Neobodo curvifilus (Griessmann, 1913)

Park, Dong Hyuk Jeong and Jong Soo, 2021, Characterizations of five heterotrophic nanoflagellates newly recorded in Korea, Journal of Species Research 10 (4), pp. 356-363 : 360-361

4. Neobodo curvifilus (Griessmann, 1913)

Moreira et al., 2004 ( Fig. 3A, B )

Synonym: Procryptobia sorokini (Zhukov, 1975) Frolov et al., 2001 .

Isolation. Dong Hyuk Jeong and Won Je Lee conducted specimen collection on 13 January 2020, from the Gwangam Beach (35°06′08.01″N, 128°30′00.09″E), Changwon , Korea. Temperature : 14.1℃, Salinity : 34.0 PSU, pH: 8.3. Morphological description. The live strain KM017 was a biflagellate form and usually ovoid or bean-shaped ( Fig. 3A, B ). The average length and width of the cell body were 7.2±0.6 μm (mean± STD) and 4.2±0.7 μm, respectively (n = 20). Sometimes, the granules were observed within its cell body ( Fig. 3A ). Cells displayed a rapid squirming movement. Furthermore, the two flagella beat heterodynamically, and had a hair-like tip. Also, the average length of the anterior and posterior flagellum was 8.6±0.9 μm and 16.5±1.8 μm, respectively (n = 20). The anterior flagellum showed quickly paddling motion, while the posterior flagellum trailed posteriorly .

Molecular phylogeny. The partial 18S rDNA sequence of the strain KM017 was 2,066 bp long (G + C content: 50%). The closest sequence retrieved by BLASTn GenBank search was the 18S rDNA sequence of Procryptobia sorokini isolate FB (accession number; KF479401, 2,053 bp long, G + C content: 50%), with a high identity of 99.66% (2047/2054 bp). Moreover, this study has shown that strain KM017 was a member of P. sorokini with a maximum bootstrap value (ML: 100%) and a posterior probability of 1 ( Fig. 3C ).

Remarks. The strain KM017 is morphologically similar to the previously reported Neobodo curvifilus . The original biflagellate cells were oval- or pear-shaped ( Frolov et al., 2001). The original cell body was 6.6-8.3 μm in length and 3.0-4.5 μm in width. The width of cell body of the strain KM017 was slightly larger than the original species. Like our isolate, granules of the original cells were also observed along the ventral side of the cells. The length of the anterior flagellum of the original cells was similar to the cell body length, whereas the length of the posterior flagellum of the original cells was 1.5 times longer than the cell body length. The anterior flagellum of the original cells often displayed a hook motion. Moreover, the length of a hair-like tip on the posterior flagellum was longer than that on the anterior flagellum ( Kim et al., 2014). The flagellar length and motion of the strain KM017 are consistent with the original cells. Furthermore, phylogenetic trees of the 18S rDNA sequences showed that the strain KM017 was a member of Neobodo curvifilus . Procryptobia sorokini in GenBank is a junior synonym of Neobodo curvifilus (W.J. Lee, personal communication).

Habitat. Surface water/sediment interface of coastal areas. Specimen deposition. National Institute of Biological Resources, Korea (KPZXPR0000000007-KPZXPR0000 000011).

Identifiers. Won Je Lee.

(A) (B)

Figures

Fig. 3. (A, B) General light micrographs and sketch of Neobodo curvifilus (formerly Procryptobia sorokini) strain KM017. AF: anterior flagellum, PF: posterior flagellum, GR: granules, scale bar=5 μm. All micrographs are differential interference contrast (DIC) images. (C) Maximum likelihood phylogenetic tree inferred from the 18S rDNA sequences of Neobodonida (order) species including Neobodo curvifilus strain KM017 and outgroup (Bodo saltans and Bodo uncinatus). Bootstrap support values (>80%) are shown at the nodes. Solid circles indicate a Bayesian posterior probability of 1 (posterior probability<0.95 not shown).