scholarly journals Morphological versus molecular delimitation of ciliate species: a case study of the family Clevelandellidae (Protista, Ciliophora, Armophorea)

2020 ◽  
Author(s):  
Lukáš Pecina ◽  
Peter Vďačný
Keyword(s):  
18S Rrna ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Gene Sequences ◽  
Molecular Analyses ◽  
Ciliate Species ◽  
The Family ◽  
Geometrical Data ◽  
Geometrical Information

The endozoic ciliates of the family Clevelandellidae Kidder, 1938 typically inhabit the hindgut of wood-feeding panesthiine cockroaches. To assess the consistency of species delimitation in clevelandellids, we tested the utility of three sources of taxonomic data: morphometric measurements, cell geometrical information, and 18S rRNA gene sequences. The morphometric and geometrical data delimited the clevelandellid morphospecies consistently and unambiguously. However, only Paraclevelandia brevis Kidder, 1937 represented a homogenous taxon in both morphological and molecular analyses; the morphospecies Clevelandella constricta (Kidder, 1937) and C. hastula (Kidder, 1937) contained two or three distinct, more or less closely related genotypes each; and the genetic homogeneity of the morphospecies C. panesthiae (Kidder, 1937) and C. parapanesthiae (Kidder, 1937) was not corroborated by the 18S rRNA gene sequences at all. Moreover, the 18S rRNA gene phylogenies suggested the C. panesthiae-like morphotype to be the ancestral phenotype from which all other clevelandellid morphotypes arose. The only exception was the C. constricta-like morphotype, which very likely branched off before the diversification of the C. panesthiae-like progenitor. The present molecular analyses also suggested that a huge proportion of the clevelandellid diversity still waits to be discovered, since examination of only four panesthiine populations revealed 10 distinct clevelandellid genotypes/molecular species.

scholarly journals Redescription and phylogenetic analyses of Thaparocleidus gomtius and T. sudhakari (Monogenea: Dactylogyridae) from Wallago attu (Siluriformes: Siluridae) in India

2017 ◽  
Vol 54 (1) ◽  
pp. 87-96 ◽  
Author(s):  
C. Verma ◽  
A. Chaudhary ◽  
H. S. Singh
Keyword(s):  
Phylogenetic Relationships ◽  
18S Rrna ◽  
Phylogenetic Analyses ◽  
Uttar Pradesh ◽  
18S Rrna Gene ◽  
Morphometric Study ◽  
Rrna Gene ◽  
Molecular Analyses ◽  
Wallago Attu ◽  
Geographical Regions

Summary Two species of Thaparocleidus Jain (1952a) were found harboring W. attu from the Ganga River at two localities, Meerut and Farrukhabad, Uttar Pradesh, India, during the period of 2013-2015. Morphology and morphometric study of specimens identified as Thaparocleidus gomtius (Jain, 1952a) Lim, 1996 and T. sudhakari (Gusev, 1976) Lim, 1996. Molecular analyses using the 18S rRNA gene confirmed the validity of T. gomtius and T. sudhakari and demonstrated that both the species clustered with other Thaparocleidus species from different geographical regions. We aim at reassessing the taxonomy and establishing the phylogenetic relationships among these two redescribed species with other representatives of the genus Thaparocleidus.

Phylogenetic relationships of the family Campulidae (Trematoda) based on 18S rRNA sequences

Parasitology ◽  
1998 ◽  
Vol 117 (4) ◽  
pp. 383-391 ◽  
Author(s):  
M. FERNANDEZ ◽  
D. T. J. LITTLEWOOD ◽  
A. LATORRE ◽  
J. A. RAGA ◽  
D. ROLLINSON
Keyword(s):  
18S Rrna ◽  
Fasciola Hepatica ◽  
18S Rrna Gene ◽  
Host Switching ◽  
Rrna Gene ◽  
Intermediate Hosts ◽  
Marine Gastropods ◽  
Echinostoma Caproni ◽  
The Family ◽  
Rrna Sequences

Traditionally, the family Campulidae has been associated either with the family Fasciolidae, parasites of ruminants, or the Acanthocolpidae, parasites of fishes, based on morphological similarities. Since morphology does not seem to resolve clearly the problem of the relationships of campulids, we have used the sequences of the 18S rRNA gene of the campulids Zalophotrema hepaticum, Campula oblonga and Nasitrema globicephalae, the fasciolid Fasciola hepatica, the acanthocolpid Stephanostomum baccatum and the outgroup Schistosoma mansoni to infer a phylogeny. Maximum parsimony and neighbour-joining methods were applied. Both methods indicated that campulids are closer to acanthocolpids than fasciolids. In order to confirm this relationship, we generated a second phylogeny using all the partial sequences of the 18S published for trematodes: Lobatostoma manteri, Echinostoma caproni, Calicophoron calicophorum, Tetracerasta blepta, Gyliauchen sp. and Opistorchis viverrini, plus those mentioned above, and Dicrocoelium dendriticum. The aspidogastrean L. manteri was used as the outgroup. Results were identical to the first analysis. According to this and the most recent Digenean phylogeny, which considers campulids and acanthocolpids as sister groups, we suggest that a common origin for these 2 groups would imply a host-switching process. The life-cycle of acanthocolpids includes marine gastropods as first intermediate hosts, and fishes as second intermediate and definitive hosts. In this context, the hypothesis would be that trematodes whose cycle ended in fishes were able to switch to mammalian hosts.

18S rRNA Gene Sequences and Supraordinal Classification of the Erysiphales

Mycologia ◽  
1994 ◽  
Vol 86 (2) ◽  
pp. 212 ◽  
Author(s):  
Gregory S. Saenz ◽  
John W. Taylor ◽  
Andrea Gargas
Keyword(s):  
18S Rrna ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Gene Sequences

scholarly journals Complex photobiont diversity in the marine lichen Lichina pygmaea

2021 ◽  
pp. 1-8
Author(s):  
Nathan A. M. Chrismas ◽  
Ro Allen ◽  
Anita L. Hollingsworth ◽  
Joe D. Taylor ◽  
Michael Cunliffe
Keyword(s):  
Environmental Conditions ◽  
Intertidal Zone ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Marine Cyanobacteria ◽  
Rrna Gene ◽  
Ecological Fitness ◽  
The Family

Abstract Lichens are a well-known symbiosis between a host mycobiont and eukaryote algal or cyanobacterial photobiont partner(s). Recent studies have indicated that terrestrial lichens can also contain other cryptic photobionts that increase the lichens’ ecological fitness in response to varying environmental conditions. Marine lichens live in distinct ecosystems compared with their terrestrial counterparts because of regular submersion in seawater and are much less studied. We performed bacteria 16S and eukaryote 18S rRNA gene metabarcoding surveys to assess total photobiont diversity within the marine lichen Lichina pygmaea (Lightf.) C. Agardh, which is widespread throughout the intertidal zone of Atlantic coastlines. We found that in addition to the established cyanobacterial photobiont Rivularia, L. pygmaea is also apparently host to a range of other marine and freshwater cyanobacteria, as well as marine eukaryote algae in the family Ulvophyceae (Chlorophyta). We propose that symbiosis with multiple freshwater and marine cyanobacteria and eukaryote photobionts may contribute to the ability of L. pygmaea to survive the harsh fluctuating environmental conditions of the intertidal zone.

scholarly journals Revealing the Composition of the Eukaryotic Microbiome of Oyster Spat by CRISPR-Cas Selective Amplicon Sequencing (CCSAS)

2021 ◽  
Author(s):  
Kevin Xu Zhong ◽  
Anna Cho ◽  
Christophe M. Deeg ◽  
Amy M. Chan ◽  
Curtis A. Suttle
Keyword(s):  
18S Rrna ◽  
Amplicon Sequencing ◽  
18S Rrna Gene ◽  
Model Organisms ◽  
Rrna Gene ◽  
Gene Sequences ◽  
Oyster Spat ◽  
Guide Rna ◽  
16S Rna ◽  
Eukaryotic Microbes

Abstract BackgroundThe microbiome affects the health of plants and animals, including humans, and has many biological, ecological and evolutionary consequences. Microbiome studies typically rely on sequencing ribosomal 16S RNA gene fragments, which serve as taxonomic markers for prokaryotic communities; however, for eukaryotic microbes this approach is compromised, because 18S rRNA gene sequences from microbial eukaryotes are swamped by contaminating host rRNA gene sequences. ResultsTo overcome this problem, we developed CRISPR-Cas Selective Amplicon Sequencing (CCSAS), a high-resolution and efficient approach for characterizing eukaryotic microbiomes. CCSAS uses taxon-specific single-guide RNA (sgRNA) to direct Cas9 to cut 18S rRNA gene sequences of the host, while leaving protistan and fungal sequences intact. We validated the specificity of the sgRNA on ten model organisms and an artificially constructed (mock) community of nine protistan and fungal pathogens. The results showed that >96.5% of host rRNA gene amplicons were cleaved, while 18S rRNA gene sequences from protists and fungi were unaffected. When used to assess the eukaryotic microbiome of oyster spat from a hatchery, CCSAS revealed a diverse community of eukaryotic microbes, typically with much less contamination from oyster 18S rRNA gene sequences than other methods using non-metazoan or blocking primers. However, each method revealed taxonomic groups that were not detected using the other methods, showing that a single approach is unlikely to uncover the entire eukaryotic microbiome in complex communities. To facilitate the application of CCSAS, we designed taxon-specific sgRNA for ~16,000 metazoan and plant taxa, making CCSAS widely available for characterizing eukaryotic microbiomes that have largely been neglected. ConclusionCCSAS provides a high-through-put and cost-effective approach for resolving the eukaryotic microbiome of metazoa and plants with minimal contamination from host 18S rRNA gene sequences. Keywords: Eukaryotic microbiome, 18S rRNA gene, Microeukaryote, CRISPR-Cas, Taxon-specific single-guide RNA, gRNA-target-site, CasOligo, CCSAS

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