MOLECULAR SYSTEMATICS OF THE FLORIDEOPHYCEAE (RHODOPHYTA) USING NUCLEAR LARGE AND SMALL SUBUNIT rDNA SEQUENCE DATA

2001 ◽  
Vol 37 (6) ◽  
pp. 1073-1082 ◽  
Author(s):  
James T. Harper ◽  
Gary W. Saunders
2013 ◽  
Vol 63 (Pt_5) ◽  
pp. 1912-1921 ◽  
Author(s):  
Xumiao Chen ◽  
Ying Yan ◽  
Xiaozhong Hu ◽  
Mingzhuang Zhu ◽  
Honggang Ma ◽  
...  

The morphology and morphogenesis of the stylonychine hypotrich Rigidohymena candens (Kahl, 1932) Berger, 2011, isolated from garden soil in Qingdao, China, were investigated using live observation and protargol impregnation methods. The Qingdao isolate possesses all diagnostic morphological characters of R. candens. The main events during binary fission are as follows: (i) the proter retains the parental adoral zone of membranelles entirely, whereas the old undulating membranes dedifferentiate into an anlage that gives rise to the leftmost frontal cirrus and the new undulating membranes of the proter; (ii) five streaks of fronto-ventral-transverse cirral anlagen are segmented in the pattern 3 : 3 : 3 : 4 : 4 from left to right, which form two frontal, four frontoventral, one buccal, five ventral and five transverse cirri, respectively; (iii) dorsal morphogenesis is in the typical Oxytricha pattern; (iv) three caudal cirri are formed, one at the posterior end of each of dorsal kineties 1, 2 and 4; and (v) the postoral ventral cirrus V/3 is not involved in primordia formation. The morphological and morphogenetic observations and phylogenetic analyses based on the small-subunit rDNA sequence data support the validity of Rigidohymena Berger, 2011 and its systematic position in the subfamily Stylonychinae.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yong Chi ◽  
Yuqing Li ◽  
Qianqian Zhang ◽  
Mingzhen Ma ◽  
Alan Warren ◽  
...  

Abstract Background Heterotrichous ciliates are common members of microeukaryote communities which play important roles in both the transfer of material and the flow of energy in aquatic food webs. This group has been known for over two centuries due to their large body size and cosmopolitan distribution. Nevertheless, species identification and phylogenetic relationships of heterotrichs remain challenging due to the lack of accurate morphological information and insufficient molecular data. Results The morphology and phylogeny of two heterotrichous ciliates, namely Gruberia foissneri spec. nov. and Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al., 1999, were studied using rigorous methods (living morphology, stained preparations, and small subunit rDNA sequence data). Gruberia foissneri spec. nov. is morphologically very similar to G. uninucleata Kahl, 1932, however, it can be distinguished from the latter by having more ciliary rows (about 32 vs. about 20) and macronuclear shape (sausage-shaped vs. ellipsoid). Based on a combination of previous and present studies, an improved diagnosis of L. vorticella is supplied and several taxonomic anomalies are clarified. In addition, phylogenetic analyses based on SSU rDNA sequence data support the generic assignment of these two species. Conclusions Modern ciliate taxonomy should be performed by means of detailed living observation, stained preparations and molecular information. For those species that have been reported in previous studies, it is necessary to provide as much useful information as possible using state-of-the-art methods in order to resolve taxonomic anomalies.


2020 ◽  
Author(s):  
Yong Chi ◽  
Yuqing Li ◽  
Qianqian Zhang ◽  
Mingzhen Ma ◽  
Alan Warren ◽  
...  

Abstract Background: Heterotrichous ciliates are common members of microeukaryote communities which play important roles in both the transfer of material and the flow of energy in aquatic food webs. This group has been known for over two centuries due to their large body size and cosmopolitan distribution. Nevertheless, species identification and phylogenetic relationships of heterotrichs remain challenging due to the lack of accurate morphological information and insufficient molecular data.Results: The morphology and phylogeny of two heterotrichous ciliates, namely Gruberia foissneri spec. nov. and Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al., 1999, were studied using rigorous methods (living morphology, stained preparations, and small subunit rDNA sequence data). Gruberia foissneri spec. nov. is morphologically very similar to G. uninucleata Kahl, 1932, however, it can be distinguished from the latter by having more ciliary rows (about 32 vs. about 20) and macronuclear shape (sausage-shaped vs. ellipsoid). Based on a combination of previous and present studies, an improved diagnosis of L. vorticella is supplied and several taxonomic anomalies are clarified. In addition, phylogenetic analyses based on SSU rDNA sequence data support the generic assignment of these two species.Conclusions: Modern ciliate taxonomy should be performed by means of detailed living observation, stained preparations and molecular information. For those species that have been reported in previous studies, it is necessary to provide as much useful information as possible using state-of-the-art methods in order to resolve taxonomic anomalies.


1993 ◽  
Vol 71 (9) ◽  
pp. 1249-1265 ◽  
Author(s):  
G. Hausner ◽  
J. Reid ◽  
G. R. Klassen

Phylogenetic analysis of partial rDNA sequences suggests that Ophiostoma should remain the sole genus of the Ophiostomataceae, and this should be the sole family within the Ophiostomatales, whereas Ceratocystis s.s. would be best disposed within the Microascales. Although morphological criteria suggest that the genus Ophiostoma is heterogeneous, analysis of partial small subunit rDNA sequence data shows that Ophiostoma (excluding O. roraimense) represents a monophyletic taxon. Analysis of a partial large subunit rDNA data set, which included sequences from 55 species assignable to Ophiostoma, failed to support the strict subdivision of the genus based on either ascospore characters or the nature of the anamorph. Key words: Ceratocystis, Microascus, Ophiostoma, partial rDNA sequences, phylogeny.


2000 ◽  
Vol 104 (4) ◽  
pp. 388-394 ◽  
Author(s):  
Mattias Dahlman ◽  
Eric Danell ◽  
Joseph W. Spatafora

Nematology ◽  
2003 ◽  
Vol 5 (3) ◽  
pp. 405-420 ◽  
Author(s):  
Rita Van Driessche ◽  
Irma Tandingan De Ley ◽  
Paul De Ley ◽  
Hendrik Segers ◽  
Wim Bert

AbstractMeasurements, line drawings and scanning electromicrographs are provided of Baujardia mirabilis gen. n., sp. n., isolated from pitcher fluid of Nepenthes mirabilis from Thailand. The new genus differs from all known nematodes in having two opposing and offset spermatheca-like pouches at the junction of oviduct and uterus. It also differs from most known Rhabditida in having four cephalic setae instead of papillae. Phylogenetic analysis of small subunit rDNA sequence data robustly places the new genus within Panagrolaimidae as a sister taxon to Panagrellus. These unusual nematodes resemble Panagrellus in body size (1.8-2.7 mm in females, 1.3-1.9 mm in males) and in the monodelphic, prodelphic female reproductive system with thickened vaginal walls and prominent postvulval sac. However, they differ from Panagrellus in the characters mentioned above, in their comparatively longer stegostom and in the shape of the male spicules. Because of its aberrant characters, inclusion of this new genus in Panagrolaimidae requires changes to the family diagnosis.


2020 ◽  
Author(s):  
Yong Chi ◽  
Yuqing Li ◽  
Qianqian Zhang ◽  
Mingzhen Ma ◽  
Alan Warren ◽  
...  

Abstract Background Heterotrichous ciliates are common members of microeukaryote communities which play important roles in the transfer of material and energy flow in aquatic food webs. This group has been known over two centuries due to their large body size and cosmopolitan distribution. Nevertheless, species identification and phylogenetic relationships of heterotrichs remain challenging due to the lack of accurate morphological information and insufficient molecular data. Results The morphology and phylogeny of two poorly known heterotrichous ciliates, Gruberia uninucleata Kahl, 1932 and Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al. , 1999, were investigated based on their living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. Based on a combination of previous and present studies, detailed morphometric data and the improved diagnoses of both species are supplied here. In addition, molecular data of the two species are reported for the first time. Phylogenetic analyses based on SSU rDNA sequence data support the generic assignment of these two species. Conclusions Two insufficiently studied species, G. uninucleata and L. vorticella , are redefined using state-of-the-art methods. Previous reports on these two species are re-evaluated in the light of present findings.


2015 ◽  
Vol 65 (Pt_7) ◽  
pp. 2292-2303 ◽  
Author(s):  
Xumiao Chen ◽  
Feng Gao ◽  
Saleh A. Al-Farraj ◽  
Khaled A. S. Al-Rasheid ◽  
Kuidong Xu ◽  
...  

A novel marine hypotrichous ciliate, Sterkiella subtropica sp. nov., was recently isolated from a mangrove wetland in Hong Kong. Its morphology, morphogenesis and systematic position have been investigated. The novel species is diagnosed by combined features of morphology, ciliature and nuclear apparatus, while its ontogenetic events present a stable pattern: (i) the six streaks of the undulating membrane (UM) and cirral anlagen are segmented in a 1 : 3 : 3 : 3 : 4 : 4 pattern from left to right, and form three frontal, four frontoventral, one buccal, five ventral and five transverse cirri; (ii) the dorsal structure is similar to most other oxytrichids; that is, in a ‘4+2’ pattern with three caudal cirri being formed. Based on the small-subunit rDNA sequence, the novel species is different from its congeners by between 21 and 35 bp, with sequence identities from 0.978 to 0.987. All molecular trees exhibited a similar topology: the monophyly of species of the genus Sterkiella is not completely supported in our analyses, and approximately unbiased tests (both including and excluding the novel species) also reject the possibility that Sterkiella is a monophyletic lineage, as indicated by the morphology-based classification.


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