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1.
Parasitol Res ; 119(10): 3255-3283, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32856113

RESUMO

Seven new species of Urocleidoides from the gills and skin of nine Neotropical fish hosts (Anostomidae, Parodontidae, and Gymnotidae) are described: Urocleidoides digitabulum n. sp. on Leporinus friderici, Leporinus octofasciatus, and Megaleporinus elongatus (Anostomidae); Urocleidoides solarivaginatus n. sp. on L. friderici, L. octofasciatus, and Leporinus striatus (Anostomidae); Urocleidoides falxus n. sp. and Urocleidoides sapucaiensis n. sp. on M. elongatus; Urocleidoides tenuis n. sp. on Apareiodon piracicabae and Apareiodon affinis (Parodontidae); Urocleidoides sinus n. sp. on L. striatus, Schizodon nasutus, and Schizodon intermedius (Anostomidae); and Urocleidoides uncinus n. sp. on Gymnotus sylvius (Gymnotidae). Urocleidoides paradoxus was also found in this study on L. friderici and included in the phylogenetic analysis. Molecular data (partial 28S rDNA and mitochondrial cytochrome oxidase subunit I) were obtained for U. digitabulum n. sp., U. tenuis n. sp., U. sinus n. sp., and U. uncinus n. sp. The identification of Urocleidoides is amended herein to include all taxonomic modifications observed in this genus over time and add new characteristics observed in the species in the present study. Phylogenetic analysis revealed Urocleidoides digitabulum n. sp. and Urocleidoides sinus n. sp. (parasites of anostomids) closely related in the tree topologies. Furthermore, the new species described herein parasitized phylogenetically distant host species (Characiformes and Gymnotiformes), suggesting the effect of the dynamic process of ecological fitting.


Assuntos
Caraciformes/parasitologia , Gimnotiformes/parasitologia , Platelmintos/isolamento & purificação , Animais , Brasil , DNA Mitocondrial/genética , DNA Ribossômico/genética , Peixes , Brânquias/parasitologia , Especificidade de Hospedeiro , Filogenia , Platelmintos/classificação , Platelmintos/genética , RNA Ribossômico 28S/genética
2.
Parasitol Res ; 119(10): 3327-3338, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32789533

RESUMO

The evolutionary history of Acanthamoeba has been substantially resolved by the 18S rDNA phylogeny which made it possible to delimit the main lines associated with some classical species. Some of them have proven to be polyphyletic, but the inappropriate use of treating under the same names unrelated strains persists. In this study, phylogenies based on the complete genes of nuclear and mitochondrial rDNA were compared, in order to verify the congruence of the different lines. Various groups can thus be identified, some of which associated with the type strains of given species. Recognizing them only by their species names would significantly reduce the current confusion, in addition to logically following basic taxonomic rules. In this manner, the well-known polyphyletic taxa A. castellanii and A. polyphaga, are restricted to the two lines specified by their type strains, while other widely used strains like Neff and Linc-AP1 that are often confused with the previous ones, can be assigned to their own lines. New species are potentially present in other groups and additional efforts are needed to delimit them.


Assuntos
Acanthamoeba/classificação , Filogenia , Acanthamoeba/genética , Animais , DNA Mitocondrial/genética , DNA Ribossômico/genética , Genes de Protozoários/genética , Genótipo
3.
Parasitol Res ; 119(10): 3339-3345, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32827102

RESUMO

Genetic variations in the 18S ribosomal DNA (18S), 28S ribosomal DNA (28S), second internal transcribed spacer of ribosomal DNA (ITS2), and mitochondrial cytochrome c oxidase subunit 1 (cox1) of Neoschoengastia gallinarum collected from subtropical China were examined. First, a portion of the 18S (p18S), a portion of the 28S (p28S), and the complete ITS2 were separately amplified from individual mites and sequenced. The lengths of the sequences of p18S, p28S, and ITS2 were found to be 1379 bp, 3465~3468 bp, and 200 bp, respectively. The intraspecific sequence variation was 0~0.1% for p28S and 0~1.6% for ITS2, though no variation was observed for p18S, suggesting conservation of rDNA sequences. Second, a portion of the mitochondrial cox1 gene (pcox1) of N. gallinarum was analyzed. The length of the pcox1 sequence is 460 bp, and two distinct groups were observed in N. gallinarum. All pcox1 sequences in group I were identical, and there was only one nucleotide transition observed in group II; however, 7.0~7.2% variations between the two groups were observed, suggesting that two genotypes of N. gallinarum: genotype I and genotype II. Phylogenetic analyses based on pcox1 sequences indicated that N. gallinarum isolates (genotype I or genotype II) clustered into one branch; according to cox1 sequence analysis of Trombiculidae, Walchia hayashii is the closest species. The present study shows that ITS2 rDNA sequence can act as marker for the identification of N. gallinarum samples. Furthermore, analysis of the mitochondrial pcox1 sequence suggests the existence of two genotypes, which has implications for further studies of the ecology and population genetic structures of N. gallinarum.


Assuntos
Ciclo-Oxigenase 1/genética , DNA Ribossômico/genética , Trombiculidae/genética , Animais , China , DNA Mitocondrial/genética , Variação Genética , Genótipo , Filogenia , Análise de Sequência de DNA , Trombiculidae/classificação
4.
Int J Syst Evol Microbiol ; 70(8): 4798-4807, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32783804

RESUMO

Leptographium panxianense and L. puerense are proposed as new taxa based on sequence data and morphological characters. The phylogenetic analyses based on ITS2-partial LSU rDNA region, ß-tubulin and elongation factor 1-α genes showed that L. panxianense and L. puerense formed well-supported clades and were closely related to L. yunnanense, L. wushanense and L. conjunctum, and then nested within the L. lundbergii complex. The two species differ in their conidial size and shape. The conidia of L. panxianense are larger than those of L. puerense while the conidial shape of L. puerense is more ovovoid. The optimal growth temperature of both L. panxianense and L. puerense is at 20 °C, which is different from those of L. yunnanense, L. wushanense and L. conjunctum. Comparison of sequence data and morphological characters confirmed the placement of the two undescribed taxa in the genus of Leptographium.


Assuntos
Besouros/microbiologia , Ophiostomatales/classificação , Filogenia , Pinus , Animais , China , DNA Fúngico/genética , DNA Ribossômico/genética , Técnicas de Tipagem Micológica , Ophiostomatales/isolamento & purificação , Fator 1 de Elongação de Peptídeos/genética , Análise de Sequência de DNA , Esporos Fúngicos , Tubulina (Proteína)/genética
5.
Protist ; 171(4): 125743, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32731120

RESUMO

The phylum Perkinsozoa is known as an exclusively parasitic group including the parasites of shellfish, fish, dinoflagellates, cryptophytes, and tadpoles and at present comprises seven genera across three families (Parviluciferaceae, Perkinsidae, and Xcellidae), with the genus Parvilucifera having the most abundant species in the family Parviluciferaceae. During intensive sampling along the Korean coast in August and September 2017, a new species of the genus Parvilucifera was discovered and successfully established in cultures. Morphological and ultrastructural observations revealed that the new parasitoid shares almost all known diagnostic characters with other species of Parvilucifera, except that its sporangium has a higher number of apertures although with smaller diameters than those in P. infectans. Molecular phylogenetic trees based on both nuclear small subunit (SSU) and concatenated SSU and large subunit (LSU) ribosomal DNA (rDNA) sequences revealed that the new parasitoid was nested within the family Parviluciferaceae and had a sister relationship with P. infectans. Based on morphological, ultrastructural, and molecular data, we propose to erect a new species, P. multicavata sp. nov., for the new parasitoid found in this study.


Assuntos
Alveolados/classificação , Dinoflagelados/parasitologia , Filogenia , Alveolados/genética , Alveolados/ultraestrutura , DNA Ribossômico/genética , República da Coreia , Água do Mar/parasitologia , Especificidade da Espécie
6.
PLoS One ; 15(7): e0235622, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614898

RESUMO

Volvox sect. Volvox is an interesting group of green algae; it comprises mostly monoicous species, but evidence suggests an evolution towards dioicy. Based on cultured strains originating from Thailand, we describe Volvox longispiniferus, a novel species in Volvox sect. Volvox. This species is distinguished from others in the section by the large number of sperm packets in its monoicous sexual spheroids and by the long spines on its zygote wall. Phylogenetic analyses indicate that V. longispiniferus is distinct from the other species of two monophyletic groups within Volvox sect. Volvox. In addition, the novel species produces more zygotes when different cultures are combined compared with a single culture, suggesting a preference for outcrossing.


Assuntos
Volvox/classificação , Cloroplastos/genética , DNA Ribossômico/classificação , DNA Ribossômico/genética , Complexo de Proteína do Fotossistema II/genética , Filogenia , Ribulose-Bifosfato Carboxilase/classificação , Ribulose-Bifosfato Carboxilase/genética , Tailândia , Volvox/genética
7.
BMC Infect Dis ; 20(1): 527, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32698804

RESUMO

BACKGROUND: Conidiobolus spp. (mainly C. coronatus) are the causal agents of rhino-facial conidiobolomycosis, a limited soft tissue infection, which is essentially observed in immunocompetent individuals from tropical areas. Rare cases of invasive conidiobolomycosis due to C. coronatus or other species (C.incongruus, C.lamprauges) have been reported in immunocompromised patients. We report here the first case of invasive pulmonary fungal infection due to Conidiobolus pachyzygosporus in a Swiss patient with onco-haematologic malignancy. CASE PRESENTATION: A 71 year-old female was admitted in a Swiss hospital for induction chemotherapy of acute myeloid leukemia. A chest CT performed during the neutropenic phase identified three well-circumscribed lung lesions consistent with invasive fungal infection, along with a positive 1,3-beta-d-glucan assay in serum. A transbronchial biopsy of the lung lesions revealed large occasionally septate hyphae. A Conidiobolus spp. was detected by direct 18S rDNA in the tissue biopsy and subsequently identified at species level as C. pachyzygosporus by 28S rDNA sequencing. The infection was cured after isavuconazole therapy, recovery of the immune system and surgical resection of lung lesions. CONCLUSIONS: This is the first description of C. pachyzygosporus as human pathogen and second case report of invasive conidiobolomycosis from a European country.


Assuntos
Conidiobolus/genética , Leucemia Mieloide Aguda/complicações , Pneumopatias Fúngicas/complicações , Pneumopatias Fúngicas/diagnóstico , Zigomicose/complicações , Zigomicose/diagnóstico , Idoso , Antifúngicos/uso terapêutico , Biópsia , Conidiobolus/isolamento & purificação , DNA Fúngico/genética , DNA Ribossômico/genética , Feminino , Humanos , Hifas/isolamento & purificação , Hospedeiro Imunocomprometido , Pneumopatias Fúngicas/tratamento farmacológico , Pneumopatias Fúngicas/patologia , Nitrilos/uso terapêutico , Piridinas/uso terapêutico , Suíça , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Triazóis/uso terapêutico , Zigomicose/tratamento farmacológico , Zigomicose/patologia
8.
Aquat Toxicol ; 226: 105556, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32652413

RESUMO

Ribosomal (r)DNA is a highly dynamic, conserved, multigene family whose sequence homogeneity is thought to be maintained by intra- and interchromosomal recombination, which are capable of changing rDNA copy number. It is generally not known how environmental stress such as sublethal exposure to environmentally relevant concentrations of metals impacts rDNA copy number. To determine how chronic metal exposure affects rDNA, we measured copy number of the 18S rRNA gene in 355 copper and nickel-exposed samples and 132 metal-free samples derived from 325 mutation accumulation (MA) lines of two genetically distinct Daphnia pulex lineages. The MA lines were sampled at four time points over 100+ generations of clonal propagation. The copy number of rDNA was also measured in 15 individuals sampled from a metal-free non-MA control population established from the same progenitor as one of the MA lineages. We found that mean rDNA copy number fluctuated across lines exposed to metals with a tendency to decrease over time. In contrast, mean rDNA copy number in the metal-free control lines and the non-MA population remained stable over time. It is generally accepted that extreme rDNA loss results in the loss of organism fitness. Thus, fluctuations in rDNA copy number, including losses, could affect the long-term viability of natural populations of Daphnia in metal-contaminated habitats.


Assuntos
Variações do Número de Cópias de DNA/efeitos dos fármacos , DNA Ribossômico/genética , Daphnia/efeitos dos fármacos , Metais Pesados/toxicidade , Acúmulo de Mutações , Poluentes Químicos da Água/toxicidade , Animais , Cobre/toxicidade , Daphnia/genética , Níquel/toxicidade , RNA Ribossômico 18S/genética , Reprodução/efeitos dos fármacos , Reprodução/genética
9.
BMC Evol Biol ; 20(1): 86, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32677880

RESUMO

BACKGROUND: Although phylogenomic analyses are increasingly used to reveal evolutionary relationships among ciliates, relatively few nuclear protein-coding gene markers have been tested for their suitability as candidates for inferring phylogenies within this group. In this study, we investigate the utility of the heat-shock protein 90 gene (Hsp90) as a marker for inferring phylogenetic relationships among hypotrich ciliates. RESULTS: A total of 87 novel Hsp90 gene sequences of 10 hypotrich species were generated. Of these, 85 were distinct sequences. Phylogenetic analyses based on these data showed that: (1) the Hsp90 gene amino acid trees are comparable to the small subunit rDNA tree for recovering phylogenetic relationships at the rank of class, but lack sufficient phylogenetic signal for inferring evolutionary relationships at the genus level; (2) Hsp90 gene paralogs are recent and therefore unlikely to pose a significant problem for recovering hypotrich clades; (3) definitions of some hypotrich orders and families need to be revised as their monophylies are not supported by various gene markers; (4) The order Sporadotrichida is paraphyletic, but the monophyly of the "core" Urostylida is supported; (5) both the subfamily Oxytrichinae and the genus Urosoma seem to be non-monophyletic, but monophyly of Urosoma is not rejected by AU tests. CONCLUSIONS: Our results for the first time demonstrate that the Hsp90 gene is comparable to SSU rDNA for recovering phylogenetic relationships at the rank of class, and its paralogs are unlikely to pose a significant problem for recovering hypotrich clades. This study shows the value of careful gene marker selection for phylogenomic analyses of ciliates.


Assuntos
Cilióforos/genética , Evolução Molecular , Proteínas de Choque Térmico HSP90/genética , Sequência de Aminoácidos , Sequência de Bases , Cilióforos/classificação , DNA Ribossômico/genética , Bases de Dados Genéticas , Bases de Dados de Proteínas , Proteínas de Choque Térmico HSP90/química , Filogenia
10.
PLoS One ; 15(7): e0235788, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634157

RESUMO

The genus Makalata is a taxonomically complex group of rodents on which few cytogenetic studies have been performed. Most of the published karyotypes were described based only on conventional chromosome staining. Here, we studied the karyotypes of Makalata from two Brazilian Amazonian states, Amapá and Pará, by Giemsa-staining, G- and C-banding, AgNO3-staining and FISH with 18S rDNA and telomeric sequences probes. We observed 2n = 66/FN = 124 in the Pará state population in Makalata sp; and 2n = 72/FN = 128 in the Amapá state population in M. didelphoides. Multiple chromosome rearrangements may have given rise to these karyotypes, which differ significantly from each other and from those reported in the literature. The chromosomal differences among the described Makalata karyotypes can act as a barrier to gene flow; since they are also associated with geographic barriers (e.g., rivers) and numerous molecular differences, they could be seen as evidence for reproductive isolation of populations from genus Makalata. Our data suggest that the genus is chromosomally diverse and the karyotypes may belong to different species. These karyotypes may prove useful as taxonomic markers for these rodents.


Assuntos
Cariótipo , Roedores/genética , Animais , Brasil , Bandeamento Cromossômico , DNA Ribossômico/genética , Fluxo Gênico , Cariotipagem , Roedores/classificação , Especificidade da Espécie , Telômero/genética
11.
BMC Evol Biol ; 20(1): 92, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727367

RESUMO

BACKGROUND: Hypotrichia are a group with the most complex morphology and morphogenesis within the ciliated protists. The classification of Gastrostyla-like species, a taxonomically difficult group of hypotrichs with a common ventral cirral pattern but various dorsal and ontogenetic patterns, is poorly understood. Hence, systematic relationships within this group and with other taxa in the subclass Hypotrichia remain unresolved. RESULTS: 18S rRNA gene sequence of a new Gastrostyla-like taxon was obtained. Phylogenetic analyses based on the 18S rRNA gene sequences indicate that this ciliate represents a new genus that is closely related to Heterourosomoida and Kleinstyla within the oxytrichid clade of the Hypotrichia. However, the position of this cluster remains unresolved. All three genera deviate from the typical oxytrichids by their incomplete (or lack of) dorsal kinety fragmentation during morphogenesis. Morphology and morphogenesis of this newly discovered form, Heterogastrostyla salina nov. gen., nov. spec., are described. Heterogastrostyla nov. gen., is characterised as follows: more than 18 fronto-ventral-transverse cirri, cirral anlagen V and VI develop pretransverse cirri, and dorsal ciliature in Urosomoida-like pattern. CONCLUSIONS: Similar to the CEUU-hypothesis about convergent evolution of urostylids and uroleptids, we speculate that the shared ventral cirral patterns of Gastrostyla-like taxa might have resulted from convergent evolution.


Assuntos
Cilióforos/classificação , Classificação , Salinidade , Solo , Animais , Sequência de Bases , Núcleo Celular/genética , DNA Ribossômico/genética , Hypotrichida/classificação , Hypotrichida/genética , Funções Verossimilhança , Morfogênese/genética , Filogenia , Subunidades Ribossômicas Menores/genética , Especificidade da Espécie
12.
Parasitol Res ; 119(10): 3221-3231, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32671541

RESUMO

Members of the genus Lueheia Travassos, 1919, are endoparasites of birds, particularly passerines, throughout the Americas. Adults of Lueheia sp., (Plagiorhynchidae Golvan, 1960; Porrorchinae Golvan, 1956) were recovered from the intestine of the American robin (Turdus migratorius phillipsi Bangs) in Mexico City, and two other species of acanthocephalans identified as Porrorchis nickoli, (Plagiorhynchidae: Porrorchinae) Salgado-Maldonado and Cruz-Reyes, 2002 and Centrorhynchus microcephalus (Bravo-Hollis, 1947) Golvan, 1956 (Centrorhynchidae Van Cleave, 1916), were recovered from the Virginia opossum (Didelphis virginiana Allen) and groove-billed ani (Crotophaga sulcirostris Swainson), respectively in southeastern Mexico. Specimens of three species were sequenced at two molecular markers, the small subunit (SSU) and large subunit (LSU) of the nuclear rDNA and compared with other sequences available in GenBank. Maximum likelihood and Bayesian inference analyses of the combined (LSU + SSU) dataset and each individual dataset revealed that the specimens of Lueheia sp. formed an independent lineage, which is recognized herein as a new species, Lueheia aztecae n. sp., representing the fifth species of the genus in the Americas, and the second in the Nearctic region. The new species can be morphologically distinguished from the other five species in the genus by having a cylindrical proboscis, armed with 24-26 longitudinal rows with 9-10 hooks each. Phylogenetic inference performed with the combined dataset consisting of two genes (LSU + SSU) revealed that Lueheia aztecae n. sp. and P. nickoli belonging to subfamily Porrorchinae, formed two independent lineages, indicating that the subfamily is paraphyletic. Porrorchis nickoli and C. microcephalus formed a clade with other species of the genus Centrorhynchus, suggesting that P. nickoli should be transferred to genus Centrorhynchus, to form C. nickoli n. comb. In addition, we briefly discuss the ecological associations between the members of the families Plagiorhynchidae and Centrorhynchidae.


Assuntos
Acantocéfalos/anatomia & histologia , Acantocéfalos/classificação , Helmintíase Animal/parasitologia , Aves Canoras/parasitologia , Acantocéfalos/genética , Animais , Sequência de Bases , Teorema de Bayes , DNA Ribossômico/genética , Marcadores Genéticos/genética , Intestinos/parasitologia , México , Filogenia
13.
Nature ; 585(7824): 298-302, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32669707

RESUMO

Proteins are manufactured by ribosomes-macromolecular complexes of protein and RNA molecules that are assembled within major nuclear compartments called nucleoli1,2. Existing models suggest that RNA polymerases I and III (Pol I and Pol III) are the only enzymes that directly mediate the expression of the ribosomal RNA (rRNA) components of ribosomes. Here we show, however, that RNA polymerase II (Pol II) inside human nucleoli operates near genes encoding rRNAs to drive their expression. Pol II, assisted by the neurodegeneration-associated enzyme senataxin, generates a shield comprising triplex nucleic acid structures known as R-loops at intergenic spacers flanking nucleolar rRNA genes. The shield prevents Pol I from producing sense intergenic noncoding RNAs (sincRNAs) that can disrupt nucleolar organization and rRNA expression. These disruptive sincRNAs can be unleashed by Pol II inhibition, senataxin loss, Ewing sarcoma or locus-associated R-loop repression through an experimental system involving the proteins RNaseH1, eGFP and dCas9 (which we refer to as 'red laser'). We reveal a nucleolar Pol-II-dependent mechanism that drives ribosome biogenesis, identify disease-associated disruption of nucleoli by noncoding RNAs, and establish locus-targeted R-loop modulation. Our findings revise theories of labour division between the major RNA polymerases, and identify nucleolar Pol II as a major factor in protein synthesis and nuclear organization, with potential implications for health and disease.


Assuntos
Nucléolo Celular/enzimologia , Nucléolo Celular/genética , DNA Ribossômico/genética , RNA Polimerase II/metabolismo , RNA não Traduzido/biossíntese , RNA não Traduzido/genética , Ribossomos/metabolismo , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Linhagem Celular Tumoral , Nucléolo Celular/fisiologia , DNA Helicases/metabolismo , DNA Intergênico/genética , Humanos , Enzimas Multifuncionais/metabolismo , Biossíntese de Proteínas , Estruturas R-Loop , RNA Helicases/metabolismo , RNA Polimerase I/antagonistas & inibidores , RNA Polimerase I/metabolismo , Ribonuclease H/metabolismo , Ribossomos/química , Ribossomos/genética , Sarcoma de Ewing/genética , Sarcoma de Ewing/patologia
14.
BMC Infect Dis ; 20(1): 441, 2020 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-32571220

RESUMO

BACKGROUND: PCRctic is an innovative assay based on 16S rDNA PCR technology that has been designed to detect a single intact bacterium in a specimen of cerebro-spinal fluid (CSF). The assay's potential for accurate, fast and inexpensive discrimination of bacteria-free CSF makes it an ideal adjunct for confident exclusion of bacterial meningitis in newborn babies where the negative predictive value of bacterial culture is poor. This study aimed to stress-test and optimize PCRctic in the "field conditions" to attain a clinically useful level of specificity. METHODS: The specificity of PCRctic was evaluated in CSF obtained from newborn babies investigated for meningitis on a tertiary neonatal unit. Following an interim analysis, the method of skin antisepsis was changed to increase bactericidal effect, and snap-top tubes (Eppendorf™) replaced standard universal containers for collection of CSF to reduce environmental contamination. RESULTS: The assay's specificity was 90.5% in CSF collected into the snap-top tubes - up from 60% in CSF in the universal containers. The method of skin antisepsis had no effect on the specificity. All CSF cultures were negative and no clinical cases of neonatal bacterial meningitis occurred during the study. CONCLUSIONS: A simple and inexpensive optimization of CSF collection resulted in a high specificity output. The low prevalence of neonatal bacterial meningitis means that a large multi-centre study will be required to validate the assay's sensitivity and its negative predictive value.


Assuntos
Líquido Cefalorraquidiano/microbiologia , Meningites Bacterianas/microbiologia , Reação em Cadeia da Polimerase/métodos , Bactérias/genética , DNA Ribossômico/genética , Estudos de Viabilidade , Humanos , Recém-Nascido , Doenças do Recém-Nascido/microbiologia , Meningites Bacterianas/diagnóstico , Sensibilidade e Especificidade
15.
Mol Cell ; 79(3): 488-503.e11, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32585128

RESUMO

Transcription elongation rates influence RNA processing, but sequence-specific regulation is poorly understood. We addressed this in vivo, analyzing RNAPI in S. cerevisiae. Mapping RNAPI by Miller chromatin spreads or UV crosslinking revealed 5' enrichment and strikingly uneven local polymerase occupancy along the rDNA, indicating substantial variation in transcription speed. Two features of the nascent transcript correlated with RNAPI distribution: folding energy and GC content in the transcription bubble. In vitro experiments confirmed that strong RNA structures close to the polymerase promote forward translocation and limit backtracking, whereas high GC in the transcription bubble slows elongation. A mathematical model for RNAPI elongation confirmed the importance of nascent RNA folding in transcription. RNAPI from S. pombe was similarly sensitive to transcript folding, as were S. cerevisiae RNAPII and RNAPIII. For RNAPII, unstructured RNA, which favors slowed elongation, was associated with faster cotranscriptional splicing and proximal splice site use, indicating regulatory significance for transcript folding.


Assuntos
RNA Polimerase III/genética , RNA Polimerase II/genética , RNA Polimerase I/genética , RNA Fúngico/química , Saccharomyces cerevisiae/genética , Elongação da Transcrição Genética , Composição de Bases , Sequência de Bases , Sítios de Ligação , Cromatina/química , Cromatina/metabolismo , DNA Ribossômico/genética , DNA Ribossômico/metabolismo , Regulação Fúngica da Expressão Gênica , Ligação Proteica , Dobramento de RNA , RNA Polimerase I/metabolismo , RNA Polimerase II/metabolismo , RNA Polimerase III/metabolismo , Sítios de Splice de RNA , Processamento de RNA , RNA Fúngico/genética , RNA Fúngico/metabolismo , Saccharomyces cerevisiae/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Termodinâmica
16.
Parasitol Res ; 119(7): 2113-2128, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32476059

RESUMO

Members of the myxosporean genus Kudoa are defined as having a myxospore with four or more shell valves (SVs) and a corresponding number of polar capsules (PCs). Here, we employed integrated taxonomic approaches to four kudoid isolates from Acentrogobius chlorostigmatoides and Konosirus punctatus from the South China Sea, off Guangdong, Pentanemus quinquarius from the Southeast Atlantic Ocean, off West African coast, and Atheresthes stomias from the Bering Sea, off Alaska, and concluded that all these kudoids were novel species, named Kudoa acentrogobia n. sp., Kudoa guangdongensis n. sp., Kudoa iidae n. sp., and Kudoa aburakarei n. sp., respectively. Kudoa guangdongensis n. sp., forming pseudocysts in the trunk muscle myofibers of K. punctatus, had large-sized tripod myxospores with three wing-like SV extensions and three PCs (one prominent PC and two rudimentary PCs). Phylogenetic analyses based on the 18S and 28S ribosomal RNA gene (rDNA) demonstrated its affinity to the genus Kudoa, not to Unicapsula characterized by a myxospore with one prominent PC and two rudimentary PCs, suggesting the atypical nature of this new species in the context of myxospore morphology. Three other kudoid isolates had four SVs and PCs in a semi-quadrated, ray-like, or cruciform myxospore, respectively, forming pseudocysts in the trunk muscle myofibers. Kudoa iidae n. sp. forming pseudocysts in the muscles of P. quinquarius from Southeast Atlantic Ocean had unique myxospores with ray-like form, showing close morphological resemblance to Kudoa rayformis, which were recorded from the muscle of Scomberomorus sierra from the Pacific Ocean off Panama. These two species had a phylogenetic relationship of morphological convergence, evolving separately in different sea areas. It is fairly difficult to differentiate K. acentrogobia n. sp. and K. aburakarei n. sp., prevalent in their host fishes, from kudoid species with similar myxospore morphology (e.g., Kudoa nova and Kudoa thyrsites, respectively), but distinct in phylogeny from known Kudoa spp. Combined taxonomic identification of multivalvulid myxosporeans based on both morphological criteria of isolated myxozoans and their molecular characterization could disclose their real biodiversity and phylogeny.


Assuntos
Myxozoa/classificação , Filogenia , Animais , Oceano Atlântico , China , DNA Ribossômico/genética , Doenças dos Peixes/parasitologia , Peixes/parasitologia , Músculo Esquelético/parasitologia , Myxozoa/citologia , Myxozoa/genética , Oceano Pacífico , RNA Ribossômico 28S/genética
17.
Parasitol Res ; 119(8): 2439-2462, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32591866

RESUMO

In 2018 and 2019, salmonid fishes, Salmo trutta L. and Salvelinus alpinus (L.) from lakes in Iceland were assessed for trematodes during a parasitological examination. Combined morphological and molecular analyses revealed the presence of four trematode species, two of which were previously known to parasitise salmonids in Iceland, Crepidostomum farionis (Müller, 1780) and Phyllodistomum umblae (Fabricius, 1780), and the two remaining species were recognised as new to science. Morphologically and genetically, Crepidostomum brinkmanni n. sp. and C. pseudofarionis n. sp. are closely related to two European species, namely C. metoecus and C. farionis. However, C. brinkmanni n. sp. is distinct by the position of maximum body width and arrangement of vitelline follicles; C. pseudofarionis n. sp. is distinct by its stout body, position of maximum body width, size of muscular papillae relative to oral sucker and the anterior extent of vitelline follicles. The new species were previously molecularly detected in their intermediate and definitive hosts in Norway and Ukraine, but their sequences were not supplemented with any morphological characterisation. In the present study, we provide detailed morphological descriptions and molecular sequences (28S rDNA and ITS2) of the four species of trematodes detected in Iceland. The discovery of the two new species of Crepidostomum indicates that the trematode diversity in fishes in the north is higher than previously known; our finding doubles the species spectrum of fish trematodes for Iceland. The record of C. brinkmanni from Ukraine indicates that its distribution might not be limited to northern latitudes.


Assuntos
Biodiversidade , Doenças dos Peixes/parasitologia , Salmonidae/parasitologia , Trematódeos/classificação , Infecções por Trematódeos/parasitologia , Animais , DNA Ribossômico/genética , Doenças dos Peixes/epidemiologia , Islândia/epidemiologia , Lagos , Filogenia , Especificidade da Espécie , Trematódeos/genética , Infecções por Trematódeos/epidemiologia
18.
Parasitol Res ; 119(7): 2359-2362, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32500368

RESUMO

Several Cryptosporidium species that infect reptiles, especially squamates, are well described, but there is limited data about Cryptosporidium species infecting crocodilians. In this study, we assess the occurrence of intestinal parasites using traditional microscopic examination and describe the prevalence and Cryptosporidium species in the captive-bred Chinese alligators (Alligator sinensis) in eastern China using molecular methods. The results of microscopic examination showed that no intestinal parasites were detected among the 491 fecal samples examined from the Chinese alligators. The overall prevalence for Cryptosporidium was 0.41% (2/491) by PCR detection using the SSU rRNA locus. Sequence and phylogenetic analysis of the SSU rRNA, COWP, and actin genes revealed the presence of Cryptosporidium testudinis, which has been isolated primarily from chelonians. This is the first detection of the specific DNA of C. testudinis in the feces of the Chinese alligator. This study expands our knowledge of the Cryptosporidium species involved in crocodiles, and more extensive studies are necessary to confirm the validity of C. testudinis in crocodiles.


Assuntos
Jacarés e Crocodilos/parasitologia , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , Animais , China/epidemiologia , Criptosporidiose/epidemiologia , Cryptosporidium/classificação , Cryptosporidium/genética , DNA de Protozoário/genética , DNA Ribossômico/genética , Fezes/parasitologia , Genes de Protozoários/genética , Filogenia
19.
Parasitol Res ; 119(8): 2463-2471, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32529296

RESUMO

Members of the genus Sphaeromyxa Thélohan, 1892 have been reported from a wide variety of fish species worldwide. In the present study, specimens of rusty blenny, Parablennius sanguinolentus, collected from Sinop on the Turkish Black Sea coast were investigated for myxosporean parasites by using both conventional and molecular methods. Sphaeromyxa sevastopoli Naidenova 1970 was the only myxosporean parasite found in the gall bladder of host fishes. The morphology peculiarities of obtained S. sevastopoli spores are in good agreement with those of original description and the morphometric data overlapped in spore length and width but differed in polar capsule length and width; however, they were within the ranges previously reported from 18 host fish species. Moreover, in the present study, molecular analysis of the 18S rDNA gene of S. sevastopoli isolate in our P. sanguinolentus as well as isolates from shore rockling Gaidropsarus mediterraneus and knout goby Mesogobius batrachocephalus which were previously morphologically identified and reported by Okkay and Özer (Acta Zool Bulg 72(1):123-130, 2020) was done for the first time and our three S. sevastopoli genotypes were allocated to the "balbianii" group which is characterized by straight or slightly curved and fusiform or ovoid spores with ovoid polar capsules.


Assuntos
Cnidários/anatomia & histologia , Cnidários/genética , Doenças dos Peixes/parasitologia , Doenças Parasitárias em Animais/parasitologia , Perciformes/parasitologia , Animais , Mar Negro , Cnidários/classificação , DNA Ribossômico/genética , Vesícula Biliar/parasitologia , Especificidade da Espécie , Turquia
20.
Mol Biol (Mosk) ; 54(2): 262-266, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32392195

RESUMO

rDNA genes play an important role in epigenetic regulation and in differentiation of eukaryotic cells. Using the 4C (circular chromosome conformation capture) approach and model HEK293T cells, we analyzed the rDNA-contacting gene FANK1, using anchor located inside rDNA genes. At the 5' end of the FANK1 gene we detected frequent contacts with rDNA clusters. The contact sites coincide with the border where chromatin state changes and nucleosome positioning. The adjacent genes DHX32, BCCIP and UROS are located in the active chromatin and are transcribed, but do not contact with rDNA genes, while FANK1 gene is silenced, and is located in repressed chromatin. Heat shock treatment dramatically changes the pattern of rDNA contacts in the region and induces about 4-fold increase in activation of the FANK1 gene. We conclude that rDNA contacts may be involved in repression of the FANK1 gene.


Assuntos
Cromatina/genética , DNA Ribossômico/genética , Proteínas de Ligação a DNA/genética , Epigênese Genética , Fatores de Transcrição/genética , Proteínas de Ligação ao Cálcio , Proteínas de Ciclo Celular , Montagem e Desmontagem da Cromatina , RNA Helicases DEAD-box , Células HEK293 , Humanos , Proteínas Nucleares , Uroporfirinogênio III Sintetase
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