Small-subunit rRNA gene sequences from representatives of selected families of the Gigartinales and Rhodymeniales (Rhodophyta). 1. Evidence for the Plocamiales ord.nov.

1994 ◽  
Vol 72 (9) ◽  
pp. 1250-1263 ◽  
Author(s):  
G. W. Saunders ◽  
G. T. Kraft

Nucleotide sequences of the nuclear, small-subunit (SSU) ribosomal RNAs, as inferred from polymerase chain reaction (PCR)-amplified products, are presented for Areschougia congesta (Turner) J. Agardh (Solieriaceae), Dasyphloea insignis Montagne (Dumontiaceae), Sarcothalia crassifolia (C. Agardh) Edyvane & Womersley (Gigartinaceae), Nizymenia australis Sonder (Nizymeniaceae), Phacelocarpus peperocarpos (Poiret) Wynne, Ardré & Silva (Phacelocarpaceae), Plocamiocolax pulvinata Setchell, Plocamium angustum (J. Agardh) J.D. Hooker, Plocamium cartilagineum (Linnaeus) Dixon (Plocamiaceae), Rhodymenia linearis J. Agardh (Rhodymeniaceae), and Sphaerococcus coronopifolius Stackhouse (Sphaerococcaceae). Phylogenetic analyses of the SSU sequences between the Plocamiaceae and members of the Sphaerococcaceae, Phacelocarpaceae, and Nizymeniaceae, with which the Plocamiaceae has been associated historically, show SSU differences of between 87 and 105 nucleotides and do not indicate a close relationship. A review of anatomical knowledge of the Plocamiaceae and Pseudoanemoniaceae and new information on vegetative and tetrasporangial development in Plocamium and Plocamiocolax are presented to buttress a case for the Plocamiales ord.nov. Representatives of the Nizymeniaceae and Phacelocarpaceae differ from one another by only nine nucleotides, suggesting that these two taxa are very closely related and perhaps not distinct at the family rank. Key words: Gigartinales, PCR, phylogeny, Plocamiales ord.nov., Pseudoanemoniaceae, Rhodophyta, small-subunit rRNA, systematics.

2010 ◽  
Vol 60 (2) ◽  
pp. 460-468 ◽  
Author(s):  
Miao Miao ◽  
Yangang Wang ◽  
Weibo Song ◽  
John C. Clamp ◽  
Khaled A. S. Al-Rasheid

Recently, an undescribed marine ciliate was isolated from China. Investigation of its morphology and infraciliature revealed it as an undescribed species representing a new genus, Eurystomatella n. gen., the type of the new family Eurystomatellidae n. fam. The new family is defined by close-set, apically positioned oral membranelles and a dominant buccal field that is surrounded by an almost completely circular paroral membrane. The new genus is defined by having a small oral membranelle 1 (M1), bipartite M2 and well-developed M3, a body surface faintly sculptured with a silverline system in a quadrangular, reticulate pattern and a cytostome located at the anterior third of a large buccal field. The type species of the new genus, Eurystomatella sinica n. sp., is a morphologically unique form that is defined mainly by the combination of a conspicuously flattened body, several caudal cilia, extremely long cilia associated with the buccal apparatus and a contractile vacuole located subcaudally. According to phylogenetic analyses of small-subunit (SSU) rRNA gene sequences, Eurystomatella clusters with the genus Cyclidium, as a sister group to the family Pleuronematidae. The great divergence in both buccal and somatic ciliature between Eurystomatella and all other known scuticociliates supports the establishment of a new family for Eurystomatella.


1996 ◽  
Vol 74 (5) ◽  
pp. 694-707 ◽  
Author(s):  
G. W. Saunders ◽  
G. T. Kraft

Nucleotide sequences of the nuclear, small-subunit ribosomal RNAs, as inferred from polymerase chain reaction amplified products, are introduced for representatives of the Dumontiaceae, Endocladiaceae, Halymeniaceae, and Kallymeniaceae of the order Cryptonemiales sensu Kylin, the Mychodeaceae, Phyllophoraceae, Schizymeniaceae, and Sebdeniaceae of the order Gigartinales sensu Kylin, and the Lomentariaceae and Rhodymeniaceae of the order Rhodymeniales. The new sequences are included in phylogenetic analyses incorporating previously published sequences from additional families of the orders Ahnfeltiales, Ceramiales, Gigartinales, Gracilariales, Palmariales, Plocamiales, and Rhodymeniales. We used the molecular data to test the validity of the taxonomic merger of the orders Gigartinales and Cryptonemiales that was proposed by G.T. Kraft and P.A. Robins in 1985. With only two exceptions (the families Halymeniaceae and Sebdeniaceae), phylogenetic analyses of the SSU data support a monophyletic origin for a combined Gigartinales–Cryptonemiales. We therefore propose the resurrection of a redefined Cryptonemiales to consist, at this time, of only the Halymeniaceae and Sebdeniaceae. Because virtually no elements of the original or recent definitions of the Cryptonemiales survive in the characterization of this taxon, we followed procedures allowed by the International Code of Botanical Nomenclature to designate it the Halymeniales ord.nov. Analysis of molecular data further indicates that the Rhodymeniales is a monophyletic assemblage distinct from both the Gigartinales and Halymeniales; it should not be merged with the Gigartinales as is occasionally suggested. Keywords: Cryptonemiales, Gigartinales, Halymeniaceae, Halymeniales, phylogeny, Rhodophyta, Sebdeniaceae, small-subunit rRNA, systematics.


2010 ◽  
Vol 60 (1) ◽  
pp. 234-243 ◽  
Author(s):  
Xiangrui Chen ◽  
Shan Gao ◽  
Weibo Song ◽  
Khaled A. S. Al-Rasheid ◽  
Alan Warren ◽  
...  

Few studies using modern methods have been carried out on ciliated protozoa in tropical marine waters. In the present work, two hypotrichs, Parabirojimia multinucleata spec. nov. and Anteholosticha scutellum (Cohn, 1866) Berger, 2003, collected from Daya Bay in southern China, were investigated morphologically. P. multinucleata is distinguished by the following combination of characters: slender body, without a snout-like protrusion in the frontal field, and about 50 macronuclear nodules. The poorly known A. scutellum has never been investigated using modern methods; hence, a redescription is needed. During the present study, observations of specimens in vivo and following protargol impregnation revealed new information concerning structures such as the cortical granules and the infraciliature. A redescription and improved diagnosis are supplied based on the China population. The small-subunit (SSU) rRNA gene was sequenced for both organisms and comparisons with those of similar congeners clearly support the findings based on morphological studies.


2013 ◽  
Vol 63 (Pt_9) ◽  
pp. 3506-3514 ◽  
Author(s):  
Ying Yan ◽  
Yuan Xu ◽  
Zhenzhen Yi ◽  
Alan Warren

Three trachelocercid ciliates, Kovalevaia sulcata (Kovaleva, 1966) Foissner, 1997, Trachelocerca sagitta (Müller, 1786) Ehrenberg, 1840 and Trachelocerca ditis (Wright, 1982) Foissner, 1996, isolated from two coastal habitats at Qingdao, China, were investigated using live observation and silver impregnation methods. Data on their infraciliature and morphology are supplied. The small subunit rRNA (SSU rRNA) genes of K. sulcata and Trachelocerca sagitta were sequenced for the first time. Phylogenetic analyses based on SSU rRNA gene sequence data indicate that both organisms, and the previously sequenced Trachelocerca ditis, are located within the trachelocercid assemblage and that K. sulcata is sister to an unidentified taxon forming a clade that is basal to the core trachelocercids.


1996 ◽  
Vol 42 (12) ◽  
pp. 1248-1251 ◽  
Author(s):  
Noriko Kikuta ◽  
Ayako Yamamoto ◽  
Nobuichi Goto

A pair of oligonucleotide primers were designed from the nucleotide sequence of the gene encoding the small subunit ribosomal RNA (SrRNA) of the oral protozoan parasite Entamoeba gingivalis. The primers amplified a 1.4-kb DNA fragment by polymerase chain reaction and were specific for Entamoeba gingivalis but not for other protozoa, oral protists and bacteria, or human leukocytes. With this method, the DNA from as few as 30 cells of Entamoeba gingivalis could be detected. These results suggest that this approach is applicable to the detection and identification of Entamoeba gingivalis in the human oral cavity.Key words: Entamoeba gingivalis, small subunit rRNA, polymerase chain reaction, diagnostics.


Zootaxa ◽  
2019 ◽  
Vol 4609 (3) ◽  
pp. 548
Author(s):  
SIBEL KIZILDAG ◽  
ISMAIL YILDIZ

In this study, Frontonia leucas, Frontonia acuminata, Frontonia angusta, and Frontonia anatolica species isolated from aquatic environments of Van in Turkey were investigated in detail using morphological, morphometrical, and molecular methods. Although there were minor differences, the Frontonia populations were morphologically similar to the other previously reported populations of the 4 species. Frontonia leucas differed from the other populations by the following combination of characters: about 200 somatic and only 3 vestibular kineties, and a single micronucleus. The Turkish population of Frontonia acuminata had just 4 vestibular kineties and the large micronucleus was always located to the anterior of the carrot-shaped macronucleus. The ratio of the oral apparey size to the cell size of Frontonia angusta in this study was about 18%, with 3 vestibular kineties, and 1 excretory pore. Phylogenetic trees based on small-subunit rRNA gene sequences were constructed using Bayesian inference and maximum-likelihood. Frontonia anatolica was more closely related to Apofrontonia dohrni and Paramecium spp. than to its congeners, while F. acuminata, like F. terricola, was also more closely related to the family Stokesiidae. The results indicated that Frontonia is a non-monophyletic genus consisting of 3 groups. We presented the systematic relationships of the genera and families of Peniculida with new data of genus Frontonia herein. 


2013 ◽  
Vol 63 (Pt_3) ◽  
pp. 1155-1164 ◽  
Author(s):  
Xumiao Chen ◽  
Miao Miao ◽  
Honggang Ma ◽  
Chen Shao ◽  
Khaled A. S. Al-Rasheid

A novel stichotrich ciliate, Strongylidium orientale sp. nov., was discovered from a mangrove river in Hong Kong, southern China, and its morphology was investigated through observations in vivo and after protargol impregnation. Cells are 80–120×35–50 µm in vivo and fusiform in shape, with rounded anterior and tapered posterior ends. It is characterized by its brackish habitat and by the presence of two types of cortical granules arranged irregularly throughout the cortex. Morphogenetic events of cell division and physiological reorganization are described. The main ontogenetic features were: (i) only the posterior portion of the parental adoral zone of membranelles was renewed by dedifferentiation of the old structures; (ii) the oral primordium in the opisthe occurred apokinetally; (iii) the left and right ventral rows originated intrakinetally and the final left ventral row was spliced from two cirri from the frontoventral cirral anlage, a short cirral row from the anlage for the right ventral row and a long cirral row which was formed from the whole anlage of the left ventral row; (iv) the marginal rows developed intrakinetally; (v) the dorsal kineties replicated entirely de novo and did not fragment; and (vi) the two macronuclear nodules fused into a mass and then divided. Based on small-subunit rRNA gene sequences, phylogenetic analyses showed a close relationship with its congener Strongylidium pseudocrassum and with the genus Pseudouroleptus.


Author(s):  
Andrew J. Gooday ◽  
Jan Pawlowski

Conqueria laevis gen. and sp. nov., a new monothalamous agglutinated foraminiferan, is described from core samples collected in the abyssal western Weddell Sea. The species is characterized by a very elongate, almost cylindrical test that usually follows a more or less curved course and has a single terminal aperture located at the end of a short neck. The wall has a very smooth outer surface and is composed of tiny (<5 μm) agglutinated particles. Very similar and presumably congeneric morphotypes occur at northern hemisphere sites, including Arctic fjords around Svalbard and the Porcupine Abyssal Plain. Molecular phylogenetic analyses, based on small subunit rRNA gene sequences, indicate that the new Weddell Sea species forms an independent lineage branching among monothalamous foraminiferans as a sister group to the clade of Psammophaga.


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