50 research outputs found
Two Oxytrichid Ciliates, Cyrtohymena primicirrata and Oxytricha granulifera (Ciliophora: Sporadotrichida: Oxytrichidae) Unknown from Korea
This study reports the discovery of two oxytrichid ciliates, Cyrtohymena primicirrata (Berger and Foissner, 1987) and Oxytricha granulifera Foissner and Adam, 1983, in Jeju Island, Korea. The morphology of the two species was studied using live observation and protargol impregnation. These species are described as follows: Cyrtohymena primicirrata has a body size in live specimens 90-140×40-60 μm, length : width ratio 2.3 : 1 on average; elongated and slender obovate in outline of body. Cortical granules are shiny yellow on the ventral and dorsal side. Adoral zone of membranelles (AZM) is covering about 48% of the cell with about 38 adoral membranelles. Arrangement of undulating membranes is ordinary Cyrtohymena pattern. Dorsal kineties is six rows with 5 μm long bristles. Oxytricha granulifera has a body size in live specimens 90-115×25-38 μm, length : width ratio 3.31 on average; elongated ellipsoidal in outline of body. Cortical granules are colorless on the ventral and dorsal side. AZM is covering 28% of the cell length in vivo with about 24 adoral membranelles. Arrangement of undulating membranes is Oxytricha pattern. Dorsal kineties is five rows with about 3 μm long dorsal bristles
First Records of Two Spirostomum Ciliates (Heterotrichea: Heterotrichida: Spirostomidae) from Korea
Two Spirostomum species collected from freshwater in Korea were identified as S. caudatum (Muller, 1786) and S. teres (Claparede and Lachmann, 1858). They are recorded for the first time in Korea. The description was based on the observation of living specimens and protargol impregnated specimens. Diagnostics of these species are as follows. Spirostomum caudatum: body size 400-450×20-30 μm in vivo, shaped long and slender with a tapered posterior part, highly contractile; macronucleus ellipsoid; adoral zone of membranelles occupied 30% of body length; somatic kineties 14-22 in number. Spirostomum teres: body size 240-460×25-40 μm in vivo, shaped long and slender with a flattened posterior end, highly contractile; cortical granules arranged in 2-3 rows; adoral zone of membranelles occupied 50% of body length; somatic kineties 20-30 in number; macronucleus ellipsoid; micronuclei 2-3 in number. Spirostomum caudatum and S. teres are the most similar congeners, but they are different in the posterior part of body (tail-like posterior part vs. flattened posterior end), length of adoral zone of membranelles in body length (1/3 vs. 1/2), and the number of somatic kineties (14-22 vs. 20-30). These populations match with European populations in morphological characters
New Records of Two Stichotrichid Ciliates, Afroamphisiella multinucleata and Pseudokahliella marina (Ciliophora: Spirotrichea: Stichotrichida) from Korea
Two stichotrichid ciliates, collected from marine waters in Jeju Island, were identified as Afroamphisiella multinucleata Foissner et al., 2002 and Pseudokahliella marina (Foissner et al., 1982) Berger et al., 1985. They are recorded for the first time in Korea. The descriptions are based on examinations of living as well as protargol- impregnated specimens. These species are characterized as follows. Afroamphisiella multinucleata has a body size in vivo of 70-95×20-35 μm; elongate rectangular in shape; contractile vacuole located slightly above mid-body. The adoral zone is bipartited into 3 distal and 13-17 proximal membranelles and occupies 28-35% of the body length. The frontal row comprises 1-4 cirri and one buccal cirrus. The amphisiellid median cirral row is composed of 14-21 cirri, 10-19 left marginal cirri, and 21-30 right marginal cirri. Cortical granules are yellowish. 11-20 globular/ellipsoidal macronuclear nodules arrange proximally along the cell margins. Pseudokahliella marina has a body size in vivo of 110-195×40-110 μm and broadly elliptical in shape. The adoral zone of the membranelles occupies 50-60% of the body length, and is composed of 41-70 membranelles. A prominent frontal scutum is present. The contractile vacuole is located below the mid-body. There are 11- 13 frontoventral rows, including marginal rows. Caudal cirri and transverse cirri are absent. Three invariable non-fragmented bipolar dorsal kineties are present. The left and right marginal rows are composed of 22-35 and 28-40 cirri, respectively. Colourless cortical granules are present. 8-11 spherical/ellipsoidal macronuclear nodules are connected with each other by thread-like tructures, forming an inverted C-shape
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
Apogastrostyla rigescens (Kahl, 1932) gen. nov., comb. nov. (Ciliophora, Hypotricha): Morphology, Notes on Cell Division, SSU rRNA Gene Sequence Data, and Neotypification
The morphology, the infraciliature, some stages of cell division and physiological reorganization, and the SSU rRNA gene sequence of the little-known marine 18-cirri hypotrich Tachysoma rigescens (Kahl, 1932) Borror, 1972 [basionym Oxytricha (Tachysoma) rigescens], isolated from mariculture waters near Qingdao, China, were investigated. This rare species is characterized, inter alia, by narrowly spaced, small, colourless cortical granules and several conspicuous ring-shaped structures in the cytoplasm. The caudal cirri and the simple dorsal kinety pattern (three bipolar kineties) are probably plesiomorphic traits within the Hypotricha, the composition of the adoral zone of the proter from new and parental membranelles, as well as the presence of two ‘extra’ cirri behind the right marginal row strongly suggest a misclassification in Tachysoma. The SSU rRNA gene sequence data indicate that T. rigescens branches off rather basally in the Hypotricha tree, which supports the hypothesis that the 18-cirri pattern occurred very early, probably already in the last common ancestor of the Hypotricha. A detailed survey of the early branching 18-cirri hypotrichs and similar taxa (e.g. Trachelostyla pediculiformis, Hemigastrostyla enigmatica, Protogastrostyla pulchra) reveals that for T. rigescens a new genus (Apogastrostyla gen. nov.) has to be established, because there are important differences, inter alia, in the dorsal infraciliature. Besides the type species, A. rigescens comb. nov., which seems to be confined to the northern hemisphere according to the sparse faunistic data, a second marine species, A. szaboi comb. nov. (basionym Hemigastrostyla szaboi), so far only twice recorded from the Antarctic region, can be included. The Chinese population is fixed as neotype to define the species objectively, because no type material of A. rigescens is present and the original type locality is not known. The species name Tachysoma multinucleate is emended: Tachysoma multinucleatum nom. corr
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Morphological Redescriptions of Three Condylostoma Ciliates (Heterotrichida: Condylostomatidae) New to Korea
Heterotrichous ciliates were isolated from marine and brackish habitats in Korea, and their morphology, infraciliature and morphometrical characters were investigated using silver impregnated methods. These three Condylostoma species were identified as Condylostoma curva Burkovsky, 1970, C. minutum Bullington, 1940 and C. spatiosum Ozaki and Yagiu in Yagiu, 1944. The species of Condylostoma based on morphology are highly variable in most of characters and distinguished as following. Condylostoma curva is oval to elongate ellipsoidal, size about 245×100 μm in vivo, and conspicuously dark greenish brown with cortical granules on their surface, buccal cavity relatively large about 40% of body length, 5-11 macronuclear nodules, 4-8 frontal cirri serially arranged and 22-38 somatic kineties. Condylostoma minutum is elongate ellipsoidal and the size about 310×55 μm in vivo, buccal field about 35% of body length, 12-20 macronuclear nodules, adoral zone consisted of 82-107 membranelles, large and long one frontal cirrus and 38-44 somatic kineties. Condylostoma spatiosum is large elongate ellipsoidal, size about 670×105 μm in vivo, buccal cavity about 25% of body length, 11-25 macronuclear nodules, 111-144 adoral membranelles, membrane-like 2 frontal cirri, 49-74 somatic kineties. These three Condylostoma species are described here for the first time in Korea
05)First(JH)(수정)
ABSTRACT Two Spirostomum species collected from freshwater in Korea were identified as S. caudatu