Partial (D1-D3) 28S rRNA gene sequences from 16 isolates of digenean parasites of the family Dicrocoeliidae recovered from 16 bird species from the Czech Republic were used for phylogenetic reconstruction. Comparison with sequences available from GenBank suggests that the genus Brachylecithum is paraphyletic, requiring further validation and possible systematic revision. Although partial 28S rDNA is relatively conserved, analyses suggest that the following taxa are synonymous: Lutztrema attenuatum = L. monenteron = L. microstomum, Brachylecithum lobatum = B. glareoli. Zonorchis petiolatus is reassigned back to the genus Lyperosomum with L. collurionis as a junior synonym. The study revealed how complicated the systematics of the family Dicrocoeliidae is currently. The morphology of the group is variable, and the current distinguishing characters at species and even generic level are not sufficiently distinctive; it is difficult to identify the specimens correctly and identification of GenBank isolates is not reliable. Extensive sampling of isolates for both molecular and morphological studies is necessary to resolve the relationships within the family.

• MeSH
• Dicrocoeliidae klasifikace   genetika   izolace a purifikace   MeSH
• fylogeneze MeSH
• infekce červy třídy Trematoda parazitologie   veterinární   MeSH
• nemoci ptáků parazitologie   MeSH
• ptáci parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

Human ribosomal DNA is represented by hundreds of repeats in each cell. Every repeat consists of two parts: a 13 kb long 47S DNA with genes encoding 18S, 5.8S, and 28S RNAs of ribosomal particles, and a 30 kb long intergenic spacer (IGS). Remarkably, transcription does not take place in all the repeats. The transcriptionally silent genes are characterized by the epigenetic marks of the inactive chromatin, including DNA hypermethylation of the promoter and adjacent areas. However, it is still unknown what causes the differentiation of the genes into active and silent. In this study, we examine whether this differentiation is related to the nucleotide sequence of IGS. We isolated ribosomal DNA from the nucleoli of human-derived HT1080 cells, and separated methylated and non-methylated DNA by chromatin immunoprecipitation. Then, we used PCR to amplify a 2 kb long region upstream of the transcription start and sequenced the product. We found that six SNVs and a series of short deletions in a region of simple repeats correlated with the DNA methylation status. These data indicate that variability of IGS sequence may initiate silencing of the ribosomal genes. Our study also suggests a number of pathways to this silencing that involve micro-RNAs and/or non-canonical DNA structures.

• MeSH
• intergenová DNA MeSH
• lidé MeSH
• mezerníky ribozomální DNA genetika   MeSH
• ribozomální DNA genetika   MeSH
• ribozomy * MeSH
• RNA ribozomální 28S genetika   MeSH
• sekvence nukleotidů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The African freshwater fish of Cichlidae are parasitized by five genera of monogeneans belonging to Dactylogyridea. Ectoparasitic Scutogyrus, Onchobdella, and the highly diversified Cichlidogyrus represent three genera located on the gills, while the endoparasitic Enterogyrus and Urogyrus are located in the stomach and the urinary bladder, respectively. Representatives of four dactylogyridean genera (except for Urogyrus) were collected from seven cichlid species in West Africa. The aim of this study was to investigate the phylogenetic relationships between ectoparasitic and endoparasitic dactylogyridaen monogeneans specific to African freshwater Cichlidae and other representatives of Dactylogyridae, including a wide range of species from both freshwater and marine environments. All phylogenetic analyses point to the polyphyletic origin of the subfamily Ancyrocephalinae. Both Enterogyrus and Onchobdella were found to be monophyletic. The phylogenetic position of Scutogyrus longicornis was placed within the Cichlidogyrus species, which suggests the non-monophyly of Cichlidogyrus. Therefore, we have proposed a taxonomical revision of the species recently considered to be Scutogyrus. However, these four dactylogyridean genera-specific to cichlids do not form a monophyletic group. Using LSU rDNA analyses, we found that Enterogyrus and Onchobdella form a clade with Protogyrodactylus, i.e., the parasite species does not live in cichlids, which suggests that endoparasitism in cichlid monogeneans is not an ancestral feature.

• MeSH
• cichlidy parazitologie   MeSH
• DNA helmintů chemie   genetika   MeSH
• fylogeneze MeSH
• mezerníky ribozomální DNA chemie   genetika   MeSH
• močový měchýř parazitologie   MeSH
• molekulární sekvence - údaje MeSH
• nemoci ryb parazitologie   MeSH
• ploštěnci klasifikace   genetika   izolace a purifikace   MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• sladká voda MeSH
• žábry parazitologie   MeSH
• žaludek parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• západní Afrika MeSH

We explored the topology of 18S and 28S rDNA units by fluorescencein situhybridization (FISH) in the karyotypes of thirteen species representatives from major groups of Primates andTupaia minor(Günther, 1876) (Scandentia), in order to expand our knowledge of Primate genome reshuffling and to identify the possible dispersion mechanisms of rDNA sequences. We documented that rDNA probe signals were identified on one to six pairs of chromosomes, both acrocentric and metacentric ones. In addition, we examined the potential homology of chromosomes bearing rDNA genes across different species and in a wide phylogenetic perspective, based on the DAPI-inverted pattern and their synteny to human. Our analysis revealed an extensive variability in the topology of the rDNA signals across studied species. In some cases, closely related species show signals on homologous chromosomes, thus representing synapomorphies, while in other cases, signal was detected on distinct chromosomes, leading to species specific patterns. These results led us to support the hypothesis that different mechanisms are responsible for the distribution of the ribosomal DNA cluster in Primates.

• Publikační typ
• časopisecké články MeSH

In human cells, ribosomal DNA (rDNA) is arranged in ten clusters of multiple tandem repeats. Each repeat is usually described as consisting of two parts: the 13 kb long ribosomal part, containing three genes coding for 18S, 5.8S and 28S RNAs of the ribosomal particles, and the 30 kb long intergenic spacer (IGS). However, this standard scheme is, amazingly, often altered as a result of the peculiar instability of the locus, so that the sequence of each repeat and the number of the repeats in each cluster are highly variable. In the present review, we discuss the causes and types of human rDNA instability, the methods of its detection, its distribution within the locus, the ways in which it is prevented or reversed, and its biological significance. The data of the literature suggest that the variability of the rDNA is not only a potential cause of pathology, but also an important, though still poorly understood, aspect of the normal cell physiology.

• MeSH
• genetická variace * MeSH
• genetické lokusy MeSH
• lidé MeSH
• promotorové oblasti (genetika) genetika   MeSH
• ribozomální DNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

In human cells, each rDNA unit consists of the ~13 kb long ribosomal part and ~30 kb long intergenic spacer (IGS). The ribosomal part, transcribed by RNA polymerase I (pol I), includes genes coding for 18S, 5.8S, and 28S RNAs of the ribosomal particles, as well as their four transcribed spacers. Being highly repetitive, intensively transcribed, and abundantly methylated, rDNA is a very fragile site of the genome, with high risk of instability leading to cancer. Multiple small mutations, considerable expansion or contraction of the rDNA locus, and abnormally enhanced pol I transcription are usual symptoms of transformation. Recently it was found that both IGS and the ribosomal part of the locus contain many functional/potentially functional regions producing non-coding RNAs, which participate in the pol I activity regulation, stress reactions, and development of the malignant phenotype. Thus, there are solid reasons to believe that rDNA locus plays crucial role in carcinogenesis. In this review we discuss the data concerning the human rDNA and its closely associated factors as both targets and drivers of the pathways essential for carcinogenesis. We also examine whether variability in the structure of the locus may be blamed for the malignant transformation. Additionally, we consider the prospects of therapy focused on the activity of rDNA.

• MeSH
• genetická variace genetika   MeSH
• intergenová DNA genetika   MeSH
• lidé MeSH
• mutace genetika   MeSH
• nádory genetika   patologie   MeSH
• nekódující RNA genetika   MeSH
• ribozomální DNA genetika   MeSH
• ribozomy genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Molecular and morphological data were gathered for specimens of species of Macvicaria Gibson & Bray, 1982 and Pseudopycnadena Saad-Fares & Maillard, 1986 (Digenea: Opecoelidae) collected from two sparid fishes, Diplodus vulgaris (Geoffroy Saint-Hilaire) and Sparus aurata L., off the Algerian coast of the Western Mediterranean. Phylogenetic analyses based on ITS1-5.8S-ITS2 and partial 28S rDNA sequences provided evidence for the distinct species status of eight Mediterranean species of Macvicaria. Novel molecular data are provided for four species, M. gibsoni n. sp. and M. crassigula (Linton, 1910) (sensu stricto) based on specimens from D. vulgaris, and M. mormyri (Stossich, 1885) and M. maamouriae Antar, Georgieva, Gargouri & Kostadinova, 2015 based on specimens from S. aurata; descriptions of the molecular voucher material of the former three species are provided. Two species were delineated within the "crassigula" species complex of Macvicaria, M. gibsoni n. sp. and M. crassigula (s. str.), the distinctive differentiating features being the distribution of the dorsal vitelline fields in the forebody, confluent in M. gibsoni n. sp. and non-confluent in M. crassigula (s. str.), and the molecular data for both markers. Sequences associated with morphological description are also provided for the type-species of Pseudopycnadena, P. fischthali Saad-Fares & Maillard, 1986, based on material from D. vulgaris.

• MeSH
• druhová specificita MeSH
• fylogeneze * MeSH
• mezerníky ribozomální DNA genetika   MeSH
• Perciformes parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• Trematoda anatomie a histologie   klasifikace   genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Acanthogyrus (Acanthosentis) maroccanus (Dollfus, 1951), an insufficiently described quadrigyrid acanthocephalan of cyprinid fishes from Northwest Africa, is redescribed based on recently collected specimens from the Algerian barb Luciobarbus callensis (Valenciennes) in Algeria. Newly observed morphological features for A. (A.) maroccanus include the arrangement of proboscis hooks (not in regular circles), the male reproductive structures extending into the copulatory bursa and the presence of a para-receptacle structure and vaginal sleeve. The mechanism of copulation of this acanthocephalan is described based on several copulating pairs. The phylogenetic position of A. (A.) maroccanus within Eoacanthocephala was assessed based on partial 28S rDNA sequences. Maximum likelihood and Bayesian inference analyses placed A. (A.) maroccanus in a clade with Palliolisentis (Demidueterospinus) ophiocephalus (Thapar, 1931), both species included in the Quadrigyridae, the only family within the Gyracanthocephala.

• MeSH
• Acanthocephala anatomie a histologie   klasifikace   MeSH
• Bayesova věta MeSH
• Cyprinidae parazitologie   MeSH
• fylogeneze * MeSH
• nemoci ryb parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Alžírsko MeSH

Fasciola jacksoni (Cobbold, 1869) is a highly prevalent (18-62%) species colonizing the liver (less frequently the lungs, kidneys, pericardia, and intestines) of Elephas maximus indicus and Elephas maximus maximus in the Indomalayan region, causing cirrhosis, hemorrhages, and connective tissue proliferation. The phylogenetic relationships of Fasciola jacksoni in relation to representative species of the superfamily Echinostomatoidea was assessed using four independent DNA regions. The analysis involved conserved (28S rDNA) and highly variable (ITS1, ITS2, and ND1) loci utilizing both mitochondrial (ND1) and nuclear (28S rDNA, ITS1, and ITS2) DNA. Although the analyses confirmed the monophyletic origin of the Fasciolidae family, all four analyzed regions suggested high similarity of Fasciola jacksoni to Fascioloides magna, member of a hitherto monotypic genus, parasitizing a variety of wild and domestic ruminants through the Holarctic. Supporting evidence stems also from the morphological similarities, host spectrum overlaps, and similarities in disease onset and progression. Fasciola jacksoni was reclassified to its genus in the nineteenth century by Cobbold based on the shared possession of dendriform system of gastric canals. However, Fascioloides magna (discovered later) shares this feature as well. Conversely, Fascioloides magna and Fasciola hepatica possess long median intestinal branches, whereas relatively shorter median intestinal branches are characteristic for Fasciola hepatica and Fasciola gigantica only. Both, Fascioloides magna and Fasciola hepatica, are also similar in their possession of small, but distinctive cephalic cone, while the larger one is typical for Fasciola hepatica and Fasciola gigantica. Reflecting the combined data, reclassification of Fasciola jacksoni as Fascioloides jacksoni comb. nov. is suggested.

• MeSH
• DNA helmintů chemie   genetika   MeSH
• Fasciola anatomie a histologie   klasifikace   genetika   izolace a purifikace   MeSH
• fylogeneze MeSH
• mezerníky ribozomální DNA chemie   genetika   MeSH
• mitochondriální DNA chemie   genetika   MeSH
• molekulární sekvence - údaje MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• sloni parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Onnia includes white rotting polypores with annual basidiocarps, a duplex context, monomitic hyphal structure, hymenial setae, and hyaline, thin-walled, smooth basidiospores. Specimens of Onnia, originating mainly from East Asia, Europe, and North America, were studied using both morphology and phylogenetic analyses. Our concatenated data set was derived from 25 collections and included (i) 25 nuc rDNA internal transcribed spacer region sequences (ITS1-5.8S-ITS2 = ITS), 17 generated in this study; and (ii) 14 nuc rDNA 28S rDNA sequences, including the D1-D2 domains, 11 of them generated in this study. The resulting maximum likelihood and Bayesian phylogenies recovered all sampled collections of Onnia as a well-supported clade. In this clade, three previously accepted species, viz., Onnia leporina, O. tomentosa, and O. triquetra, received strong support, whereas three additional lineages with strong support represent the new species described in this paper, O. subtriquetra, O. microspora, and O. tibetica. Of the six Onnia species occurring on gymnosperms, O. tomentosa and O. leporina grow mainly on Picea and have circumboreal distribution in the Northern Hemisphere. In contrast, other species that mostly grow on Pinus are geographically restricted to limited regions, viz., O. triquetra in Europe, O. subtriquetra in North America, and O. microspora and O. tibetica in Asia.

• MeSH
• Basidiomycota klasifikace   cytologie   genetika   izolace a purifikace   MeSH
• borovice mikrobiologie   MeSH
• DNA fungální chemie   genetika   MeSH
• fylogeografie * MeSH
• genetická variace * MeSH
• mezerníky ribozomální DNA chemie   genetika   MeSH
• mikroskopie MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální 28S genetika   MeSH
• RNA ribozomální 5.8S genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• smrk mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Dálný východ MeSH
• Evropa MeSH
• Severní Amerika MeSH