Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 121
Filtrar
1.
Zootaxa ; 4981(1): 197200, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34186947

RESUMO

Psorospermium cf. haeckeli Hilgendorf 1883 is a unicellular, eukaryotic protozoan within the class Mesomycetozoea, phylogenetically situated near the animal-fungal divergence(Cavalier-Smith 1998; Ragan et al. 1998). Although only one species has been identified, there have been four morphotypes described in 17 species of crayfish from the Holarctic, Neotropical, and Australasian regions (Herbert 1987; Henttonen et al. 1992, 1994; Rug Vogt 1994). However, molecular analyses of the internal transcribed spacer DNA suggest morphotypes may represent distinct species (Bangyeekhun et al. 2001).


Assuntos
Astacoidea/parasitologia , Mesomycetozoea/classificação , Animais , DNA Intergênico , Michigan
2.
Dis Aquat Organ ; 144: 123-131, 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33955850

RESUMO

Preliminary evidence suggests that Chinook salmon Oncorhynchus tshawytscha from the Yukon River may be more susceptible to Ichthyophonus sp. infections than Chinook from stocks further south. To investigate this hypothesis in a controlled environment, we experimentally challenged juvenile Chinook from the Yukon River and from the Salish Sea with Ichthyophonus sp. and evaluated mortality, infection prevalence and infection load over time. We found that juvenile Chinook salmon from a Yukon River stock were more susceptible to ichthyophoniasis than were those from a Salish Sea stock. After feeding with tissues from infected Pacific herring Clupea pallasii, Chinook salmon from both stocks became infected. The infection was persistent and progressive in Yukon River stock fish, where infections sometimes progressed to mortality, and histological examinations revealed parasite dissemination and proliferation throughout the host tissues. In Salish Sea-origin fish, however, infections were largely transient; host mortalities were rare, and parasite stages were largely cleared from most tissues after 3-4 wk. Susceptibility differences were evidenced by greater cumulative mortality, infection prevalence, parasite density, proportion of fish demonstrating a cellular response, and intensity of the cellular response among fish from the Yukon River stock. These observed differences between Chinook salmon stocks were consistent when parasite exposures occurred in both freshwater and seawater. These results support the hypothesis that a longer-standing host-pathogen relationship, resulting in decreased disease susceptibility, exists among Salish Sea Chinook salmon than among Yukon River conspecifics.


Assuntos
Doenças dos Peixes , Mesomycetozoea , Animais , Doenças dos Peixes/epidemiologia , Rios , Salmão , Yukon
3.
PLoS One ; 16(4): e0241026, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33886557

RESUMO

Asteroid wasting events and mass mortality have occurred for over a century. We currently lack a fundamental understanding of the microbial ecology of asteroid disease, with disease investigations hindered by sparse information about the microorganisms associated with grossly normal specimens. We surveilled viruses and protists associated with grossly normal specimens of three asteroid species (Patiriella regularis, Stichaster australis, Coscinasterias muricata) on the North Island / Te Ika-a-Maui, Aotearoa New Zealand, using metagenomes prepared from virus and ribosome-sized material. We discovered several densovirus-like genome fragments in our RNA and DNA metagenomic libraries. Subsequent survey of their prevalence within populations by quantitative PCR (qPCR) demonstrated their occurrence in only a few (13%) specimens (n = 36). Survey of large and small subunit rRNAs in metagenomes revealed the presence of a mesomycete (most closely matching Ichthyosporea sp.). Survey of large subunit prevalence and load by qPCR revealed that it is widely detectable (80%) and present predominately in body wall tissues across all 3 species of asteroid. Our results raise interesting questions about the roles of these microbiome constituents in host ecology and pathogenesis under changing ocean conditions.


Assuntos
Densovirus/isolamento & purificação , Mesomycetozoea/isolamento & purificação , Estrelas-do-Mar/parasitologia , Estrelas-do-Mar/virologia , Animais , Densovirus/genética , Mesomycetozoea/genética , Metagenoma , Metagenômica , Microbiota , Nova Zelândia
4.
Dis Aquat Organ ; 143: 129-138, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570046

RESUMO

Ichthyophonus infection was first detected in Peruvian Oncorhynchus mykiss in 1986, but the occurrence of ichthyophonosis disease in the region is unknown. This study investigated the presence and distribution of Ichthyophonus sp. in Peruvian rainbow trout using traditional and DNA sequencing tools. Between 2007 and 2008, 205 rainbow trout from 13 hatcheries in the Mantaro river basin were examined for the presence of Ichthyophonus, and at that time only 3 farms were positive. This early study confirmed the presence of Ichthyophonus sp. in the Tranca Grande lagoon for the first time, at a prevalence of 50%. In 2012, examination of 240 trout from 24 fish farms in 2 Peruvian Departments found 9 infected farms. More recently, in 2018, Ichthyophonus sp. was found in Lake Titicaca, infecting a trout in the Ichu area (in the Department of Puno). Our molecular analysis of the infected trout showed that ichthyophonosis disease in the Peruvian trout was caused by Ichthyophonus sp. Clade C. The finding of this pathogen in Lake Titicaca should be an alert for nearby farms and entities dealing with fish of economic importance in the rivers of Peru.


Assuntos
Doenças dos Peixes , Mesomycetozoea , Oncorhynchus mykiss , Animais , Doenças dos Peixes/epidemiologia , Mesomycetozoea/genética , Peru/epidemiologia , Rios
5.
J Fish Dis ; 43(12): 1571-1577, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32914485

RESUMO

The Carpathian brook lamprey (Eudontomyzon danfordi Regan, 1911) is an endemic protected species of Cephalaspidomorphi in the Carpathian Basin. No parasites have become known from these jawless vertebrates to date. Here, the authors describe an infection from a single specimen manifesting in protuberant skin cysts 7-10 mm in diameter, scattered on the body surface. Similar dermal infection was observed in 25 of the 274 lampreys recorded in the population survey. Skin cysts filled with round spore-like structures of a dermocystid parasite were found. These particles measured 8-14 µm in diameter and had an about 0.5 µm thick wall, and containing mainly a granular mass and a relatively scarce plasma. No hyphae were recorded. Despite conspicuous morphological changes in the skin, no inflammatory reactions were found. The molecular analysis of 18S rDNA showed similarity to dermocystid species of several fish species but differed from them approximately by 2%. This is the first record of a dermocystid parasite infecting a jawless vertebrate.


Assuntos
Doenças dos Peixes/parasitologia , Lampreias , Mesomycetozoea/isolamento & purificação , Animais , Doenças dos Peixes/epidemiologia , Hungria/epidemiologia , Mesomycetozoea/genética , Infecções por Mesomycetozoea/epidemiologia , Pele/parasitologia
6.
Zoology (Jena) ; 141: 125813, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32623097

RESUMO

Amphibian parasites of the genus Amphibiocystidium are members of the class Ichthyosporea (=Mesomycetozoea), within the order Dermocystida. Most of the species in the Dermocystida fail to grow in ordinary culture media, so their life cycle has only been partially constructed by studies in host tissues. However, to date, there have been few reports on the life cycle of Amphibiocystidium parasites with respect to the developmental life stages of both Dermocystidium and Rhinosporidium parasites. In this study, we provide light and electron microscopic findings of developmental phenotypes of Amphibiocystidium sp., a parasite previously characterized in the Italian stream frog (Rana italica), which has caused an ongoing infection in a natural population of Central Italy. These phenotypes exhibited distinct morphological characteristics that were similar to A. ranae from the skin of R. temporaria, but showed histochemical properties particularly comparable with those of maturing phenotypes of Rhinosporidium seeberi, and compatible with fungal-like parasites. Therefore, for Amphibiocystidium sp. phenotypes, we suggest adopting the terminology used for maturing stages of R. seeberi, such as juvenile sporangia, early mature sporangia and mature sporangia. The characterization of these developmental stages will be useful to increase the understanding of the life cycle of parasites of the genus Amphibiocystidium and of the interactions with their amphibian hosts.


Assuntos
Infecções por Mesomycetozoea/parasitologia , Mesomycetozoea/crescimento & desenvolvimento , Ranidae/parasitologia , Dermatopatias Parasitárias/veterinária , Animais , Cistos , Dermatopatias Parasitárias/parasitologia
7.
Mol Phylogenet Evol ; 151: 106891, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32562822

RESUMO

Caullerya mesnili is a common and virulent parasite of the water flea, Daphnia. It was classified within the Haplosporidia (Rhizaria) for over a century. However, a recent molecular phylogeny based on the 18S rRNA gene suggested it belonged to the Ichthyosporea, a class of protists closely related to animals within the Opisthokonta clade. The exact phylogenetic position of C. mesnili remained uncertain because it appeared in the 18S rRNA tree with a very long branch and separated from all other taxa, suggesting that its position could be artifactual. A better understanding of its phylogenetic position has been constrained by a lack of molecular markers and the difficulty of obtaining a suitable quantity and quality of DNA from in vitro cultures, as this intracellular parasite cannot be cultured without its host. We isolated and collected spores of C. mesnili and sequenced genomic libraries. Phylogenetic analyses of a newly generated multi-protein data set (22 proteins, 4998 amino acids) and of sequences from the 18S rRNA gene both placed C. mesnili within the Ichthyophonida sub-clade of Ichthyosporea, as sister-taxon to Abeoforma whisleri and Pirum gemmata. Our study highlights the utility of metagenomic approaches for obtaining genomic information from intracellular parasites and for more accurate phylogenetic placement in evolutionary studies.


Assuntos
Daphnia/parasitologia , Mesomycetozoea/classificação , Mesomycetozoea/genética , Fases de Leitura Aberta/genética , Parasitos/classificação , Parasitos/genética , Filogenia , Animais , Sequência de Bases , Evolução Biológica , Funções Verossimilhança , RNA Ribossômico 18S/genética
8.
Genome Biol Evol ; 12(9): 1664-1678, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32533833

RESUMO

The Holozoa clade comprises animals and several unicellular lineages (choanoflagellates, filastereans, and teretosporeans). Understanding their full diversity is essential to address the origins of animals and other evolutionary questions. However, they are poorly known. To provide more insights into the real diversity of holozoans and check for undiscovered diversity, we here analyzed 18S rDNA metabarcoding data from the global Tara Oceans expedition. To overcome the low phylogenetic information contained in the metabarcoding data set (composed of sequences from the short V9 region of the gene), we used similarity networks by combining two data sets: unknown environmental sequences from Tara Oceans and known reference sequences from GenBank. We then calculated network metrics to compare environmental sequences with reference sequences. These metrics reflected the divergence between both types of sequences and provided an effective way to search for evolutionary relevant diversity, further validated by phylogenetic placements. Our results showed that the percentage of unicellular holozoan diversity remains hidden. We found novelties in several lineages, especially in Acanthoecida choanoflagellates. We also identified a potential new holozoan group that could not be assigned to any of the described extant clades. Data on geographical distribution showed that, although ubiquitous, each unicellular holozoan lineage exhibits a different distribution pattern. We also identified a positive association between new animal hosts and the ichthyosporean symbiont Creolimax fragrantissima, as well as for other holozoans previously reported as free-living. Overall, our analyses provide a fresh perspective into the diversity and ecology of unicellular holozoans, highlighting the amount of undescribed diversity.


Assuntos
Organismos Aquáticos/genética , Evolução Biológica , Coanoflagelados/genética , Animais , Código de Barras de DNA Taxonômico , Mesomycetozoea/fisiologia , RNA Ribossômico 18S/genética , Simbiose
10.
Parasit Vectors ; 13(1): 81, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32066491

RESUMO

BACKGROUND: Sphaerothecum destruens is an obligate intracellular fish parasite which has been identified as a serious threat to freshwater fishes. Taxonomically, S. destruens belongs to the order Dermocystida within the class Ichthyosporea (formerly referred to as Mesomycetozoea), which sits at the animal-fungal boundary. Mitochondrial DNA (mtDNA) sequences can be valuable genetic markers for species detection and are increasingly used in environmental DNA (eDNA) based species detection. Furthermore, mtDNA sequences can be used in epidemiological studies by informing detection, strain identification and geographical spread. METHODS: We amplified the entire mitochondrial (mt) genome of S. destruens in two overlapping long fragments using primers designed based on the cox1, cob and nad5 partial sequences. The mt-genome architecture of S. destruens was then compared to close relatives to gain insights into its evolution. RESULTS: The complete mt-genome of Sphaerothecum destruens is 23,939 bp in length and consists of 47 genes including 21 protein-coding genes, 2 rRNA, 22 tRNA and two unidentified open reading frames. The mitochondrial genome of S. destruens is intronless and compact with a few intergenic regions and includes genes that are often missing from animal and fungal mt-genomes, such as, the four ribosomal proteins (small subunit rps13 and 14; large subunit rpl2 and 16), tatC (twin-arginine translocase component C), and ccmC and ccmF (cytochrome c maturation protein ccmC and heme lyase). CONCLUSIONS: We present the first mt-genome of S. destruens which also represents the first mt-genome for the order Dermocystida. The availability of the mt-genome can assist the detection of S. destruens and closely related parasites in eukaryotic diversity surveys using eDNA and assist epidemiological studies by improving molecular detection and tracking the parasite's spread. Furthermore, as the only representative of the order Dermocystida, its mt-genome can be used in the study of mitochondrial evolution of the unicellular relatives of animals.


Assuntos
Doenças dos Peixes/parasitologia , Peixes/parasitologia , Genoma Mitocondrial , Mesomycetozoea/genética , Animais , Primers do DNA/genética , Marcadores Genéticos , Filogenia
11.
Vet Pathol ; 57(2): 316-320, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32079507

RESUMO

Over a 3-year-period, 17 wild-caught opaleye (Girella nigricans) housed in a public display aquarium were found dead without premonitory signs. Grossly, 4 animals had pinpoint brown or black foci on coelomic adipose tissue. Histologically, liver, spleen, heart, and posterior kidney had mesomycetozoan granulomas in all cases; other organs were less commonly infected. Four opaleye had goiter; additional substantial lesions were not identified. Granulomas surrounded melanized debris, leukocytes, and mesomycetozoa represented by folded membranes (collapsed schizont walls), intact schizonts (50- to >200 µm in diameter with a multilaminate membrane), plasmodia (budding from schizonts or free in tissue), or rarely germinal tubes (budding from schizonts). Ichthyophonus was grown from fresh tissues in tissue explant broth cultures of the heart, liver, and/or spleen. Polymerase chain reaction using 18S ribosomal DNA primers amplified a 1730-bp region, and the DNA sequence was most similar to Ichthyophonus hoferi, which is often associated with freshwater aquaculture fish.


Assuntos
Doenças dos Peixes/parasitologia , Mesomycetozoea/isolamento & purificação , Perciformes/parasitologia , Animais , Primers do DNA/genética , Feminino , Doenças dos Peixes/patologia , Coração/parasitologia , Rim/parasitologia , Rim/patologia , Fígado/parasitologia , Fígado/patologia , Masculino , Mesomycetozoea/genética , Miocárdio , Filogenia , Reação em Cadeia da Polimerase/veterinária , Baço/parasitologia , Baço/patologia
12.
Parasitology ; 147(3): 360-370, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31840622

RESUMO

Ichthyosporean parasites (order Dermocystida) can cause morbidity and mortality in amphibians, but their ecology and epidemiology remain understudied. We investigated the prevalence, gross and histologic appearance, and molecular phylogeny of a novel dermocystid in the state-endangered silvery salamander (Ambystoma platineum) and the co-occurring, non-threatened small-mouthed salamander (Ambystoma texanum) from Illinois. Silvery salamanders (N = 610) were sampled at six ephemeral wetlands from 2016 to 2018. Beginning in 2017, 1-3 mm raised, white skin nodules were identified in 24 silvery salamanders and two small-mouthed salamanders from five wetlands (prevalence = 0-11.1%). Skin biopsy histology (N = 4) was consistent with dermocystid sporangia, and necropsies (N = 3) identified infrequent hepatic sporangia. Parasitic 18S rRNA sequences (N = 5) from both salamander species were identical, and phylogenetic analysis revealed a close relationship to Dermotheca viridescens. Dermocystids were not identified in museum specimens from the same wetlands (N = 125) dating back to 1973. This is the first report of Dermotheca sp. affecting caudates in the Midwestern United States. Future research is needed to determine the effects of this pathogen on individual and population health, and to assess whether this organism poses a threat to the conservation of ambystomatid salamanders.


Assuntos
Ambystoma , Infecções por Mesomycetozoea/epidemiologia , Mesomycetozoea/fisiologia , Animais , Espécies em Perigo de Extinção , Illinois , Masculino , Mesomycetozoea/citologia , Mesomycetozoea/genética , Infecções por Mesomycetozoea/parasitologia , Prevalência , RNA Ribossômico 18S/análise
13.
Dis Aquat Organ ; 136(2): 157-162, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31621648

RESUMO

The prevalence of Ichthyophonus infection in Pacific herring Clupea pallasii was spatially heterogeneous in the southern Salish Sea, Washington State, USA. Over the course of 13 mo, 2232 Pacific herring were sampled from 38 midwater trawls throughout the region. Fork length was positively correlated with Ichthyophonus infection at all sites. After controlling for the positive relationship between host size and Ichthyophonus infection, the probability of infection was approximately 6-fold higher in North Hood Canal than in Puget Sound and the northern Straits (12 vs. 2% predicted probability for a 100 mm fish and 30 vs. 7% predicted probability for a 180 mm fish). Temporal changes in Ichthyophonus infection probability were explained by seasonal differences in fish length, owing to Pacific herring life history and movement patterns. Reasons for the spatial heterogeneity remain uncertain but may be associated with density-dependent factors inherent to the boom-bust cycles that commonly occur in clupeid populations.


Assuntos
Doenças dos Peixes , Infecções por Mesomycetozoea , Mesomycetozoea , Animais , Peixes , Oceanos e Mares , Washington
14.
Elife ; 82019 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-31647412

RESUMO

In animals, cellularization of a coenocyte is a specialized form of cytokinesis that results in the formation of a polarized epithelium during early embryonic development. It is characterized by coordinated assembly of an actomyosin network, which drives inward membrane invaginations. However, whether coordinated cellularization driven by membrane invagination exists outside animals is not known. To that end, we investigate cellularization in the ichthyosporean Sphaeroforma arctica, a close unicellular relative of animals. We show that the process of cellularization involves coordinated inward plasma membrane invaginations dependent on an actomyosin network and reveal the temporal order of its assembly. This leads to the formation of a polarized layer of cells resembling an epithelium. We show that this stage is associated with tightly regulated transcriptional activation of genes involved in cell adhesion. Hereby we demonstrate the presence of a self-organized, clonally-generated, polarized layer of cells in a unicellular relative of animals.


Assuntos
Actomiosina/metabolismo , Membrana Celular/metabolismo , Polaridade Celular , Mesomycetozoea/fisiologia , Animais , Regulação da Expressão Gênica
15.
An Acad Bras Cienc ; 91(3): e20180959, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31553369

RESUMO

The genus Dermocystidium is very comprehensive in the host and site of infection, however this is the first report of the occurrence of Dermocystidium sp. in the gills of Nile tilapia. This study was carried out in a fish farming located in the state of Santa Catarina, Brazil. No mortalities were reported in the facility studied and the animals were clinically healthy. During the histopathological analysis of the gills, 8.33% of the fish presented spores of Dermocystidium sp. in the gill tissue. The spores reported herein had a mean length and width of 6.206 x 5.233 µm and a refractile body diameter of 1.965 µm and were studied by histopathology and Transmission Electron Microscopy. This study highlights the importance of a new branchial pathogen in farmed tilapia, as well as to its pathogenic potential, considering the outbreaks of mortalities associated with other fish species.


Assuntos
Ciclídeos/parasitologia , Doenças dos Peixes/parasitologia , Infecções por Mesomycetozoea/parasitologia , Mesomycetozoea/isolamento & purificação , Animais , Aquicultura , Brasil , Mesomycetozoea/ultraestrutura , Microscopia Eletrônica de Transmissão
16.
J Aquat Anim Health ; 31(4): 349-353, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31464347

RESUMO

The ingestion of infected prey is the most recognizable mode of transmission for Ichthyophonus, but because this mode of transmission is unidirectional from small prey fish to larger predators, it cannot sustain the parasite within or among populations nor does it explain transmission to planktivores. Recently, waterborne transmission was demonstrated in cultured Rainbow Trout Oncorhynchus mykiss, which could explain how the parasite is transmitted without piscivory. However, it is possible that this is an adaptation to aquaculture conditions, and may not occur among wild fish. To address this question, experiments were conducted to determine if a freshwater isolate of Ichthyophonus is infectious and pathogenic to marine species, as well as if transmission is possible between different marine species. Pacific Staghorn Sculpins Leptocottus armatus were fed a freshwater isolate of Ichthyophonus (clade C) and then housed with susceptible sentinel Rock Soles Lepidopsetta bilineata. Ninety two percent of the orally exposed sculpins and 30% of the sentinel soles were Ichthyophonus-positive at the end of the study, with 0% infected controls. These results demonstrate that a freshwater isolate of Ichthyophonus is infectious and pathogenic to marine species and can be transmitted in seawater in the absence of piscivory. It also provides a plausible mechanism for transmission to small prey fish and planktivores, as well as within a population of piscivores when infected prey is not available.


Assuntos
Doenças dos Peixes/transmissão , Peixes , Infecções por Mesomycetozoea/transmissão , Mesomycetozoea/fisiologia , Animais , Doenças dos Peixes/parasitologia , Linguados , Água Doce , Infecções por Mesomycetozoea/parasitologia , Água do Mar
17.
Parasitology ; 146(7): 903-910, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30816081

RESUMO

Mesomycetozoean-induced infections (order Dermocystida, genus Amphibiocystidium) in European and North American amphibians are causing alarm. To date, the pathogenicity of these parasites in field conditions has been poorly studied, and demographic consequences on amphibian populations have not been explored. In this study, an Amphibiocystidium sp. infection is reported in a natural population of the Italian stream frog (Rana italica) of Central Italy, over a 7-year period from 2008 to 2014. Light and electron microscope examinations, as well as partial 18S rDNA sequence analysis were used to characterize the parasite. Moreover, a capture-mark-recapture study was conducted to assess the frog demographics in response to infection. Negative effects of amphibiocystidiosis on individual survival and population fitness were absent throughout the sampling period, despite the high estimates of disease prevalence. This might have been due to resistance and/or tolerance strategies developed by the frogs in response to the persistence of Amphibiocystidium infection in this system. We hypothesized that in the examined R. italica population, amphibiocystidiosis is an ongoing endemic/epidemic infection. However, ecological and host-specific factors, interacting in a synergistic fashion, might be responsible for variations in the susceptibility to Amphibiocystidium infection of both conspecific populations and heterospecific individuals of R. italica.


Assuntos
Infecções por Mesomycetozoea/epidemiologia , Mesomycetozoea/patogenicidade , Ranidae/parasitologia , Animais , Biópsia , Suscetibilidade a Doenças , Feminino , Interações Hospedeiro-Parasita , Itália/epidemiologia , Estudos Longitudinais , Masculino , Mesomycetozoea/genética , Prevalência , Rios/parasitologia , Pele/parasitologia , Pele/patologia
18.
BMC Genomics ; 19(1): 932, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30547741

RESUMO

BACKGROUND: Regulatory circuits of infection in the emerging experimental model system, water flea Daphnia and their microparasites, remain largely unknown. Here we provide the first molecular insights into the response of Daphnia galeata to its highly virulent and common parasite Caullerya mesnili, an ichthyosporean that infects the gut epithelium. We generated a transcriptomic dataset using RNAseq from parasite-exposed (vs. control) Daphnia, at two time points (4 and 48 h) after parasite exposure. RESULTS: We found a down-regulation of metabolism and immunity-related genes, at 48 h (but not 4 h) after parasite exposure. These genes are involved in lipid metabolism and fatty acid biosynthesis, as well as microbe recognition (e.g. c-type lectins) and pathogen attack (e.g. gut chitin). CONCLUSIONS: General metabolic suppression implies host energy shift from reproduction to survival, which is in agreement with the known drastic reduction in Daphnia fecundity after Caullerya infection. The down-regulation of gut chitin indicates a possible interaction between the peritrophic matrix and the evading host immune system. Our study provides the first description of host transcriptional responses in this very promising host-parasite experimental system.


Assuntos
Daphnia/genética , Sistema Imunitário/metabolismo , Intestinos/parasitologia , Metabolismo dos Lipídeos/genética , Mesomycetozoea/fisiologia , Animais , Daphnia/metabolismo , Regulação para Baixo , Ácido Graxo Sintases/genética , Interações Hospedeiro-Parasita , Sistema Imunitário/parasitologia , RNA/química , RNA/isolamento & purificação , RNA/metabolismo , Análise de Sequência de RNA , Transcriptoma
19.
Curr Biol ; 28(20): 3288-3295.e5, 2018 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-30318349

RESUMO

The emergence of multicellular animals was associated with an increase in phenotypic complexity and with the acquisition of spatial cell differentiation and embryonic development. Paradoxically, this phenotypic transition was not paralleled by major changes in the underlying developmental toolkit and regulatory networks. In fact, most of these systems are ancient, established already in the unicellular ancestors of animals [1-5]. In contrast, the Microprocessor protein machinery, which is essential for microRNA (miRNA) biogenesis in animals, as well as the miRNA genes themselves produced by this Microprocessor, have not been identified outside of the animal kingdom [6]. Hence, the Microprocessor, with the key proteins Pasha and Drosha, is regarded as an animal innovation [7-9]. Here, we challenge this evolutionary scenario by investigating unicellular sister lineages of animals through genomic and transcriptomic analyses. We identify in Ichthyosporea both Drosha and Pasha (DGCR8 in vertebrates), indicating that the Microprocessor complex evolved long before the last common ancestor of animals, consistent with a pre-metazoan origin of most of the animal developmental gene elements. Through small RNA sequencing, we also discovered expressed bona fide miRNA genes in several species of the ichthyosporeans harboring the Microprocessor. A deep, pre-metazoan origin of the Microprocessor and miRNAs comply with a view that the origin of multicellular animals was not directly linked to the innovation of these key regulatory components.


Assuntos
Evolução Molecular , Mesomycetozoea/genética , MicroRNAs/genética , Animais , Sequência de Bases , Mesomycetozoea/metabolismo , MicroRNAs/metabolismo , Filogenia
20.
Zootaxa ; 4461(4): 499-518, 2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30314064

RESUMO

Amphibian parasites of the Order Dermocystida (Ichthyosporea) are widespread pathogens known mainly from Europe and North America, which cause primarily a disease of skin and subcutaneous tissue in their hosts. The taxonomy of these organisms has been problematic given their conserved morphology, similar clinical disease and pathology. Currently recognized taxa belong to the three closely related genera, Amphibiocystidium, Amphibiothecum, and Rhinosporidium, whereas species of Dermocystidium and Sphaerothecum destruens include fish parasites. Here, we review the taxonomy of Dermocystida based on a molecular phylogenetic analysis, principally of amphibian parasites, including DNA sequences obtained from amphibian hosts collected in the central-eastern region of South America. A new taxonomic arrangement is proposed, which includes the designation of type material for Dermocystidium pusula, synonymization of Amphibiothecum with Dermocystidium, and the restriction of Amphibiocystidium to its type species A. ranae. We also review the taxonomic status of Dermosporidium hylarum until the present work included in the synonymy of the human and animal pathogen R. seeberi, and considered herein as a valid taxon, however. In addition, a new species of Sphaerothecum parasitic to amphibians is described, being the first record of this genus in the southern hemisphere and in an amphibian host.


Assuntos
Mesomycetozoea , Parasitos , Anfíbios , Animais , Brasil , Humanos , Filogenia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...