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1.
Int J Parasitol ; 44(3-4): 189-203, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24326177

RESUMO

The presence of a new microsporidium is believed to be responsible for an emaciative syndrome observed in farmed gilthead sea bream (Sparus aurata) from different facilities along the Spanish coast. Infected fish were approximately half the average weight and significant mortality was attributed to the condition in some facilities. Clinical signs included anorexia, cachexia and pale internal organs. The microsporidium was found mainly in the intestinal mucosa and occasionally in the submucosa. Morphological, histopathological, ultrastructural and molecular phylogenetic studies were conducted to characterise this organism. This microsporidium undergoes intranuclear development in rodlet cells and enterocytes, and cytoplasmic development mainly in enterocytes and macrophages. The nucleus-infecting plasmodium contains several diplokarya and displays polysporous development which occurs without an interfacial envelope. In the host cell cytoplasm, the parasite develops within a membrane-bound matrix. In both infection locations, the polar tube precursors appear as disks, first with lucent centres, then as fully dense disks as they fuse to form the polar filament, all before division of the plasmodium into sporoblasts. Up to 16 intranuclear spores result from the sporogonic development of a single plasmodium, whereas more than 40 spores result from several asynchronous reproductive cycles in the cytoplasmic infection. Fixed spores are ellipsoidal and diplokaryotic, with five to six coils of an isofilar polar filament in a single row. ssrDNA-based molecular phylogenetic inference places this parasite as a sister clade to crustacean-infecting species of the Enterocytozoonidae and closer to Enterocytozoon bieneusi than to other fish-infecting microsporidians presenting intranuclear development, i.e. Nucleospora, Paranucleospora and Desmozoon. Our studies result in the erection of a new species, Enterospora nucleophila, within the family Enterocytozoonidae, and the description of this family is amended accordingly to accommodate the features of known species assigned to it. Severe histopathological damage occurs in intense infections and this microsporidian is considered a serious emerging threat in sea bream production.


Assuntos
Apansporoblastina/classificação , Apansporoblastina/patogenicidade , Doenças dos Peixes/microbiologia , Microsporidiose/veterinária , Dourada/microbiologia , Animais , Apansporoblastina/genética , Núcleo Celular/microbiologia , Núcleo Celular/ultraestrutura , Citoplasma/microbiologia , Citoplasma/ultraestrutura , DNA Fúngico/genética , DNA Fúngico/isolamento & purificação , Doenças dos Peixes/patologia , Interações Hospedeiro-Patógeno , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Microscopia Eletrônica de Transmissão , Microsporidiose/microbiologia , Microsporidiose/patologia , Dados de Sequência Molecular , Filogenia
2.
J Eukaryot Microbiol ; 57(2): 95-114, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20070452

RESUMO

Paranucleospora theridion n. gen, n. sp., infecting both Atlantic salmon (Salmo salar) and its copepod parasite Lepeophtheirus salmonis is described. The microsporidian exhibits nuclei in diplokaryotic arrangement during all known life-cycle stages in salmon, but only in the merogonal stages and early sporogonal stage in salmon lice. All developmental stages of P. theridion are in direct contact with the host cell cytoplasm or nucleoplasm. In salmon, two developmental cycles were observed, producing spores in the cytoplasm of phagocytes or epidermal cells (Cycle-I) and in the nuclei of epidermal cells (Cycle-II), respectively. Cycle-I spores are small and thin walled with a short polar tube, and are believed to be autoinfective. The larger oval intranuclear Cycle-II spores have a thick endospore and a longer polar tube, and are probably responsible for transmission from salmon to L. salmonis. Parasite development in the salmon louse occurs in several different cell types that may be extremely hypertrophied due to P. theridion proliferation. Diplokaryotic merogony precedes monokaryotic sporogony. The rounded spores produced are comparable to the intranuclear spores in the salmon in most aspects, and likely transmit the infection to salmon. Phylogenetic analysis of P. theridion partial rDNA sequences place the parasite in a position between Nucleospora salmonis and Enterocytozoon bieneusi. Based on characteristics of the morphology, unique development involving a vertebrate fish as well as a crustacean ectoparasite host, and the results of the phylogenetic analyses it is suggested that P. theridion should be given status as a new species in a new genus.


Assuntos
Apansporoblastina/classificação , Apansporoblastina/crescimento & desenvolvimento , Copépodes/parasitologia , Estágios do Ciclo de Vida , Salmo salar/parasitologia , Animais , Apansporoblastina/genética , Apansporoblastina/isolamento & purificação , Núcleo Celular/parasitologia , Citoplasma/parasitologia , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Epiderme/parasitologia , Células Epiteliais/parasitologia , Genes de RNAr , Dados de Sequência Molecular , Fagócitos/parasitologia , RNA de Protozoário/genética , RNA Ribossômico 18S/genética , Análise de Sequência de DNA , Esporos de Protozoários/citologia
3.
Dis Aquat Organ ; 65(3): 217-26, 2005 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-16119890

RESUMO

A xenoma-inducing microsporidian species was found to infect the liver of the teleost fish, peacock wrasse Symphodus (Crenilabrus) tinca. Minimal estimates of the prevalence of the parasite in fishes caught along Tunisian coasts were as high as 43 % for Bizerte samples (over 2 yr) and 72% for Monastir samples (over 3 yr). Developmental stages were dispersed within a xenoma structure that was bounded only by the plasma membrane of the hypertrophic host cell. Ultrastructural features support allocation to the genus Microgemma Ralphs and Matthews, 1986. Meronts were multinucleate plasmodia and were surrounded by rough endoplasmic reticulum (RER) of the host cell. Merogonic plasmodia developed into sporogonic plasmodia, with loss of the RER interface. Sporogony was polysporoblastic. Ovocylindrical spores (3.6 x 1.2 microm) harbored a lamellar polaroplast and a polar tube that was coiled 9 times. Spore features and host specificity led us to propose a new species, Microgemma tincae. The conversion of M. tincae xenomas into well-visible cyst structures or granulomas reflected an efficient host response involving the infiltration of phagocytic cells, degradation of various parasite stages and formation of a thick fibrous wall. The small subunit rDNA gene of M. tincae was partially sequenced. Phylogenetic analysis confirms the placement within the family Tetramicriidae represented by the genera Tetramicra and Microgemma.


Assuntos
Apansporoblastina/genética , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Microsporidiose/veterinária , Perciformes , Filogenia , Animais , Apansporoblastina/classificação , Apansporoblastina/fisiologia , Apansporoblastina/ultraestrutura , Sequência de Bases , Análise por Conglomerados , DNA Ribossômico/genética , Fígado/parasitologia , Microscopia Eletrônica de Transmissão/veterinária , Microsporidiose/epidemiologia , Dados de Sequência Molecular , Análise de Sequência de DNA/veterinária , Especificidade da Espécie , Tunísia/epidemiologia
4.
J Eukaryot Microbiol ; 51(6): 678-85, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15666726

RESUMO

The genus Brachiola is the newest microsporidian genus established for a human infection with the type species being B. vesicularum in skeletal muscle. Subsequently, the microsporidium, Nosema algerae, identified from mosquitoes, was added to this genus because of morphological and physiological similarities. The present report illustrates a confirmed case of Brachiola algerae infecting skeletal muscle in a 56-year-old woman who was being treated for rheumatoid arthritis with immunosuppressive drugs. In the following study, these two human-infecting microsporidian species are ultrastructurally compared from human biopsy tissue. Additionally, Brachiola algerae from mosquitoes as reference B. algerae, was grown in athymic mice and compared to the human isolate in vivo, and in culture. B. algerae is morphologically identical in the host situations presented and different from B. vesicularum in human skeletal muscle. B. algerae has a consistently, slightly longer spore that typically contains one row of polar filament coils, while B. vesicularum typically contains two rows of polar filament coils and occasionally, one or three rows. In proliferative development, B. vesicularum forms protoplasmic extensions which do not occur on B. algerae, nor have they been reported on any other microsporidium. This report demonstrates that B. vesicularum and B. algerae are two different species of Brachiola that infect human skeletal muscle.


Assuntos
Apansporoblastina/isolamento & purificação , Apansporoblastina/ultraestrutura , Animais , Apansporoblastina/classificação , Culicidae/parasitologia , Feminino , Humanos , Microscopia Eletrônica , Pessoa de Meia-Idade , Músculo Esquelético/parasitologia , Doenças Parasitárias/parasitologia , Doenças Parasitárias em Animais/parasitologia , Esporos de Protozoários/ultraestrutura
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