Morphology, Ciliary Pattern and Molecular Phylogeny of Trachelophyllum brachypharynx Levander, 1894 (Litostomatea, Haptoria, Spathidiida)

We isolated a relatively unknown haptorian ciliate, Trachelophyllum brachypharynx, in brackish water from the mouth of the Taehwa River, South Korea. The morphology of this isolate was studied using in vivo observation and protargol impregnation, and its evolutionary history was revealed by phylogenetic analysis of the 18S rRNA gene. The main features of T. brachypharynx include (i) a very narrowly fusiform and slightly contractile body about 380 × 40 μm in size; (ii) two ellipsoidal macronuclear nodules typically connected by a fine strand; (iii) a single terminal contractile vacuole; (iv) filiform extrusomes that are typically 30 µm long; (v) an average of 24 ciliary rows, with two of them anteriorly differentiated into an isostichad dikinetidal dorsal brush; and (vi) hat-shaped lepidosomes. Based on the 18S rRNA gene phylogeny, T. brachypharynx clustered together with Trachelophyllum sp. within the order Spathidiida. Furthermore, phylogenetic trees and networks indicate some members from the genera Enchelyodon and Spathidium as the nearest relatives of trachelophyllids. Therefore, based on the present molecular and comparative-morphological analyses, we suggested a hypothesis explaining how trachelophyllids may have evolved from a spathidiid-like ancestor via an enchelyodonid-like stage

Morphology, Ciliary Pattern and Molecular Phylogeny of Trachelophyllum brachypharynx Levander, 1894 (Litostomatea, Haptoria, Spathidiida)

We isolated a relatively unknown haptorian ciliate, Trachelophyllum brachypharynx, in brackish water from the mouth of the Taehwa River, South Korea. The morphology of this isolate was studied using in vivo observation and protargol impregnation, and its evolutionary history was revealed by phylogenetic analysis of the 18S rRNA gene. The main features of T. brachypharynx include (i) a very narrowly fusiform and slightly contractile body about 380 × 40 μm in size; (ii) two ellipsoidal macronuclear nodules typically connected by a fine strand; (iii) a single terminal contractile vacuole; (iv) filiform extrusomes that are typically 30 µm long; (v) an average of 24 ciliary rows, with two of them anteriorly differentiated into an isostichad dikinetidal dorsal brush; and (vi) hat-shaped lepidosomes. Based on the 18S rRNA gene phylogeny, T. brachypharynx clustered together with Trachelophyllum sp. within the order Spathidiida. Furthermore, phylogenetic trees and networks indicate some members from the genera Enchelyodon and Spathidium as the nearest relatives of trachelophyllids. Therefore, based on the present molecular and comparative-morphological analyses, we suggested a hypothesis explaining how trachelophyllids may have evolved from a spathidiid-like ancestor via an enchelyodonid-like stage

Morphological Redescriptions and Molecular Phylogeny of Three Stentor Species (Ciliophora: Heterotrichea: Stentoridae) from Korea

Taher, Md Abu, Kabir, Ahmed Salahuddin, Shazib, Shahed Uddin Ahmed, Kim, Min Seok, Shin, Mann Kyoon (2020): Morphological Redescriptions and Molecular Phylogeny of Three Stentor Species (Ciliophora: Heterotrichea: Stentoridae) from Korea. Zootaxa 4732 (3): 435-452, DOI: https://doi.org/10.11646/zootaxa.4732.3.

Discovery of a new hypotrich ciliate from petroleum contaminated soil

<div><p>Pollution after oil spill represents extreme habitat for survival and is a major concern for loss of species diversity in the affected area. In this study, we investigated soil samples collected from a petrochemical industry, Ulsan, South Korea. The soil was in the phase of recovery from the contamination of crude oil spill. Detailed investigation, based on morphology, ontogenesis, and molecular phylogenetic methods, resulted in discovery of a novel hypotrich ciliate, i.e., <i>Metasterkiella koreana</i> n. gen., n. sp., which is morphologically characterized by a semirigid body, undulating membranes in <i>Oxytricha</i> pattern, 18 frontal-ventral-transverse cirri with cirrus V/3 placed posteriorly, one right and one left row of marginal cirri, four dorsal kineties, two dorsomarginal rows, and caudal cirri at the end of dorsal kineties 1, 2, and 4. Interestingly, during ontogenesis, formation of three common anlagen for the proter and the opisthe and involvement of cirrus V/3 in anlagen formation was observed. The dorsal ontogenesis was typical of oxytrichids, i.e., simple fragmentation of dorsal kinety 3 and formation of dorsomarginal rows close to the right marginal row. The new species was found to be similar with <i>Sterkiella subtropica</i>, except for some minor differences in morphometry, and at gene level with only one base pair difference. In phylogenetic analyses, based on SSU rRNA gene sequence, <i>M</i>. <i>koreana</i> cluster in a clade away from <i>Sterkiella</i> species, which could be explained by the differences in the morphogenetic pattern between these two genera. It is proposed that <i>S</i>. <i>subtropica</i> probably belongs to <i>Metasterkiella</i>; however, we do not perform changes and wait for the reinvestigation of its morphogenetic pattern.</p></div

Line diagrams of protargol stained early dividers of <i>Metasterkiella koreana</i>.

<p><b>(A)</b> Oral primordium develops close to transverse cirri. <b>(B)</b> Two anlagen arise from anterior of the oral primordium. (<b>C, D</b>) Anlage II of the opisthe moves anteriorly incorporating the postoral cirrus IV/2, part of this anlage merges with the parental buccal cirrus in early divider. Arrowhead points to the de novo origin of the rightmost anlagen for the proter and the opisthe. (<b>E, F</b>) The anterior portion of the de novo originated anlage moves anteriorly; while the posterior portion elongates incorporating cirrus V/3 and splits longitudinally forming anlagen V and VI of the opisthe. Postoral cirrus V/4 disaggregates and contributes to form the growing anlage IV of the opisthe. A rare specimen (F), showing the late disaggregation of cirrus V/3 (double arrowheads), already dissolved in previous stages. Overall, six parental cirri (II/2, III/2, IV/2, IV/3, V/3, and V/4) disaggregate to give rise to five fronto-ventral—transverse anlagen for proter and opisthe. AM, adoral membranelles; AZM, adoral zone of membranelles; E, endoral membrane; FC3, frontal cirrus 3; FVC, frontoventral cirri; LM, left marginal row; MA, macronuclear nodules; OP, oral primordium; P, paroral membrane; PC, postoral cirri; RM, right marginal row; TC, transverse cirri; V/3, V/4, postoral ventral cirri. Numerals denote cirral anlagen. Scale bars = 40 μm.</p

Line diagrams of protargol stained early (A–C, F), middle (D, G), and late dividers (E) of <i>Metasterkiella koreana</i>.

<p>(<b>A, B</b>) The anterior portion of the de novo originated anlage splits longitudinally forming anlagen V and VI of the proter. Cirrus IV/3 begins to disagreegate forming proter’s anlage IV, cirrus III/2 form the anlage III. <b>(C)</b> Four anlagen for marginal cirri develop incorporating four to five parental marginal cirri in the proter and the opisthe. (<b>D, E</b>) The newly formed fronto-ventral-transverse cirri migrate to their specific sites and dorsomarginal kineties develop close to the newly formed right marginal row. (<b>F, G</b>) Specimens, showing the details of the morphogenetic event on the dorsal surface with respect to the nuclear division. Within row formation of the anlagen for dorsal kineties 1–3 (F). Dorsal kinety 3 undergoes simple fragmentation forming kineties 3 and 4 (G). Caudal cirri are formed at the posterior end of dorsal kineties 1, 2, and 4, and the newly formed dorsomarginal kineties shift to the dorsal surface. AM, adoral membranelles; AZM, adoral zone of membranelles; CC, caudal cirri; DK1–4, dorsal kineties; DM1,2, dorsomarginal kineties; FC3, frontal cirrus 3; LM, left marginal row; MA, macronuclear nodules; OP, oral primordium; P, paroral membrane; RM, right marginal row; TC, transverse cirri; Numbers denote cirral anlagen. Scale bars = 40 μm.</p

Line diagrams of <i>Metasterkiella koreana</i> from life (A–E) and after protargol impregnation (F, G).

<p><b>(A)</b> A representative cell with a length of 85 μm. (<b>B, C</b>) Body shape of partially starved (B) and well fed (C) specimens. <b>(D)</b> Dorsolateral view. <b>(E)</b> Cytoplasmic crystals. (<b>F, G</b>) Ventral view of the holotype (F) and dorsal view of a paratype specimen (G), showing the ciliature and the nuclear apparatus. AZM, adoral zone of membranelles; CC, caudal cirri; DK1,4, dorsal kineties; DM1,2, dorsomarginal kineties; E, endoral membrane; LM, left marginal row; MA, macronuclear nodules; MI, micronuclei; P, paroral membrane; RM, right marginal row; I/1, II/3, III/3, frontal cirri; II/2, buccal cirrus; III/2, IV/3, VI/3, VI/4, fronto-ventral cirri; IV/2, V/4, V/3, postoral ventral cirri; V/2, VI/2, pretransverse ventral cirri; II/1, III/1, IV/1, V/1, VI/1, transverse cirri. Scale bars = 40 μm.</p

Photomicrographs of <i>Metasterkiella koreana</i> after protargol impregnation.

<p>For explanation refer to the legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0178657#pone.0178657.g004" target="_blank">Fig 4A–4F</a>. Double arrowheads and arrowheads in (C–E) point the anterior and the posterior portion of the rightmost anlagen for the proter and the opisthe which originates de novo. Arrowhead in (F) points to the disaggregating cirrus III/2 which forms anlage III of the proter. AZM, adoral zone of membranelles; E, endoral membrane; FC3, frontal cirrus 3; FVC, frontoventral cirri; LM, left marginal row; MA, macronuclear nodules; MI, micronuclei; OP, oral primordium; RM, right marginal row; TC, transverse cirri; V/3, V/4, postoral ventral cirri. Numerals denote cirral anlagen. Scale bars = 40 μm.</p

Morphometric data on <i>Metasterkiella koreana</i> n. gen., n. sp.

<p>Morphometric data on <i>Metasterkiella koreana</i> n. gen., n. sp.</p