Balanion masanensis n. sp. (ciliophora: prostomatea) from the coastal waters of Korea: morphology and small subunit ribosomal RNA gene sequence.
The planktonic ciliate Balanion masanensis n. sp. is described from living cells, from cells prepared by quantitative protargol staining (QPS), scanning electron microscopy (SEM), and transmitted electron microscopy (TEM) preparations, and the sequence of its nuclear small subunit rDNA (SSU rDNA) is reported. This species is almost ovoid with a flattened anterior oral region when the cells are alive and stained. The flattened anterior region of a living cell often forms a dome with the perimeter receded in a groove, and this region is easily inflated or depressed. In SEM photos, a brosse of six to nine monokinetids (or possibly three to five dikinetids) was observed inside the circumoral dikinetids. In TEM photos, circumoral microtubular ribbons were observed below the oral cilia, which along with the oral flaps were 8-16 microm in length. The cytostome is a slight funnel-like central depression on the flattened anterior end. The morphological characteristics of this ciliate are identical to those of the genus Balanion (Order Prorodontida). The ranges (and mean+/-standard deviation) of cell length, cell width, and oral diameter of living cells (n=23-26) were 27-43 microm (35.2+/-4.6), 25-32 microm (28.6+/-2.3), and 25-30 microm (27.6+/-1.3), respectively, while those of the QPS-stained specimens (n=70) were 23-37 microm (30.6+/-3.5), 26-35 microm (30.7+/-2.2), and 26-33 microm (29.5+/-1.5), respectively. Forty-six to 55 somatic kineties (SKs) were equally spaced around the cell body and extended from the oral to near the posterior regions with 24-50 monokinetids per kinety. Each kinetid bore a cilium 2.8-7.2 microm long. A caudal cilium (ca 14 microm long) arose on the posterior end. The single ellipsoid macronucleus is 6.8-13.4 x 6.8-10.5 microm, accompanied by a single micronucleus (2.0-2.8 x 1.5-2.5 microm) visible only in QPS specimens. Because, the cell size, the number of SKs, and the number of kinetosomes per SK of this ciliate were much greater than those of Balanion comatum and Balanion planctonicum, the only two Balanion species so far reported, we have established B. masanensis n. sp. When properly aligned, the sequence of the SSU rDNA of B. masanensis n. sp. (GenBank Accession No. AM412525) was approximately 9% different from that of Coleps hirtus (Colepidae, Prorodontida) and 12% different from that of Prorodon teres (Prorodontidae, Prorodontida).
Kim
Jae Seong
JS
School of Earth and Environmental Science, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea.
Jeong
Hae Jin
HJ
Lynn
Denis H
DH
Park
Jae Yeon
JY
Lim
Young Woon
YW
Shin
Woongghi
W
D000818:Animals; D016798:Ciliophora / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure*; D016054:DNA, Protozoan / Q000032:analysis / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000032:analysis; D020459:Genes, rRNA / Q000235:genetics*; D007723:Korea; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010802:Phylogeny; D010933:Plankton; D012623:Seawater / Q000469:parasitology; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D016054:DNA, Protozoan; D004275:DNA, Ribosomal