Cafeteria burkhardae Schoenle and Arndt, 2020

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 : 357-358

1. Cafeteria burkhardae Schoenle and Arndt, 2020

( Fig. 1A, B )

Isolation. Dong Hyuk Jeong and Jong Soo Park conducted specimen collection on 27 February 2020, from the Yeongildae Beach (36°03′49.00″N, 129°23′12.12″E), Pohang , Korea. Temperature: 12℃, Salinity: 30.0 PSU, pH: 7.7 .

Morphological description. The live strain PH 003 was a D-shaped biflagellate ( Fig. 1A, B ). The average length and width of the cell body were 4.9±0.6 μm (mean± STD) and 4.6±0.8 μm, respectively (n = 20). The curved channel on the surface of the cell was not observed. Sometimes, contractile and food vacuoles were presented within the cell body ( Fig. 1A ). The average length of the anterior and posterior flagellum was 5.8±0.8 μm and 4.7±1.3 μm, respectively (n = 20). When cells swam, the anterior flagellum was directed forwards, and beat with amplitude motion. Whereas, when the posterior flagellum was attached to a substrate, cells showed in the jerking movement, and the anterior flagellum created a feeding current.

Molecular phylogeny. The partial 18S rDNA sequence of the strain PH 003 was 1,610 bp long (G + C content:

(A) (C)

46%). The closest sequence returned by the BLASTn GenBank search was the 18S rDNA sequence of Cafeteria burkhardae strain HFCC187 (accession number; MN315602, 2,590 bp long, G + C content: 51%), with an identity of 100% (1610/1610 bp). Furthermore, the molecular phylogenetic tree of 18S rDNA sequences indicated that the strain PH 003 belonged to the C. burkhardae clade with high statistical support (ML: 99%) and a posterior probability of 1 ( Fig. 1E ).

Remarks. The strain PH 003 resembled C. roenbergensis in cell shape, and moving and feeding behaviors ( Larsen and Patterson, 1990; Lee, 2006). However, the length of the posterior flagellum of the strain PH 003 was shorter than those of C. roenbergensis CCAP 1900 /1 (mean of 6.3 μm, Schoenle et al., 2020) and the original C. burkhardae (6.1-7.4 μm, Schoenle et al., 2020). Morphologically, the strain PH 003 is very similar to C. burkhardae among Cafeteria species. The original C. burkhardae was D- or globular-shaped and ventrally flattened ( Schoenle et al., 2020). The original cell body was 3.0-4.8 μm in length and 2.6-4.5 μm in width. The length of the two flagella of the original cells was also about 5-8 μm. When the posterior flagellum of the original cells was attached to a substrate, cells showed a jerking movement, whereas the anterior flagellum created a feeding current. Additionally, the curved channel on the original and strain PH 003 cell surface was not observed. Consistently, the 18S rDNA sequence of the strain PH 003 was 100% identical to those of C. burkhardae strains HFCC32 and HFCC197. Thus, we considered them the same species.

Habitat. Surface water/sediment interface of coastal areas. Specimen deposition. National Institute of Biological Resources, Korea (KPZXPR0000000012-KPZXPR0000 000016).

Identifiers. Dong Hyuk Jeong and Jong Soo Park.

Figures

Fig. 1. (A, B) General light micrographs and sketch of Cafeteria burkhardae strain PH003. AF: anterior flagellum, PF: posterior flagellum, CV: contractile vacuole, FV: food vacuole, scale bar=5 μm. Arrowhead represents curved channel.All micrographs are differential interference contrast (DIC) images. (C, D) General light micrographs and sketch of Cafeteria graefeae strain UL001. (E) Maximum likelihood phylogenetic tree inferred from the 18S rDNA sequences of Cafeteria(genus) species including Cafeteria graefeae strain UL001 and Cafeteria burkhardae strain PH003 and outgroup (Paramonas globosa strain ATCC 50531 and Nerada mexicana strain ATCC 50535). Bootstrap support values (>70%) are shown at the nodes. Solid circles indicate a Bayesian posterior probability of 1 (posterior probability<0.95 not shown).