Taxonomia e sistemática de Ceratomyxa sp. (Cnidaria: Myxozoa), parasito de Rhaphiodon vulpinus (Characiformes: Cynodontidae) da Bacia Amazônica
Data
2021-11-29
Autores
Franzolin, Gustavo Negrão 
Orientadores
Adriano, Edson Aparecido
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Os peixes da Bacia Amazônica são hospedeiros de diversos parasitos, como os cnidários da
Classe Myxozoa (mixozoários), com aproximadamente 2600 espécies conhecidas. Dentro dos
mixozoários destacam-se as espécies do gênero Ceratomyxa Thélohan, 1892, que são parasitos
de peixes marinhos, mas estudos recentes vêm descrevendo novas espécies parasitando peixes
de água doce na América do Sul. Neste trabalho, uma espécie de Ceratomyxa de água doce
parasitando a vesícula biliar de Rhaphiodon vulpinus Spix & Agassiz, 1829 (Characiformes:
Cynodontidae) do rio Tapajós, estado do Pará, Brasil foi descrita. Sua caracterização foi
baseada em análises morfológicas obtidas por meio de microscopia de luz e eletrônica de
transmissão, dados moleculares (sequenciamento da pequena subunidade de DNA ribossomal
- SSU rDNA) e análises filogenéticas. A espécie aqui estudada desenvolve plasmódios com
formato e motilidade semelhantes a vermes. Os mixosporos de Ceratomyxa sp. são alongados,
com extremidades arredondadas, tendo seu interior composto por um esporoplasma binucleado
e duas cápsulas polares de tamanhos iguais, as quais contêm túbulos polares com 3 espirais. A
análise ultraestrutural mostrou diferentes estágios de desenvolvimento plasmodial na vesícula
biliar do hospedeiro e diferentes estágios de desenvolvimento esporogônico no interior dos
plasmódios. O sequenciamento da SSU rDNA resultou em uma sequência de 1448 pares de
bases, que não correspondeu a nenhuma sequência de espécies de mixosporídeos disponíveis
no GenBank. A análise filogenética revelou a formação de um clado composto por espécies do
gênero Ceratomyxa de água doce, onde Ceratomyxa sp. parasito de R. vulpinus agrupou como
espécie irmã de Ceratomyxa vermiformis. Com os dados morfológicos e moleculares aqui
obtidos, pode-se concluir que Ceratomyxa sp. é uma espécie ainda não descrita na literatura.
Fish from the Amazon Basin are host of several parasites, such as the cnidarians of the Class Myxozoa (myxozoans), with approximately 2600 described species. Within the myxozoans we highlight the species of the genus Ceratomyxa Thélohan, 1892, that infect majority marine fishes, but in recent studies have been described several new species parasitizing South American freshwater fish. In this work, a freshwater species of Ceratomyxa species parasitizing the gallbladder of Rhaphiodon vulpinus Spix & Agassiz, 1829 (Characiformes: Cynodontidae) from Tapajós river, Pará state, Brazil is described. Its characterization was based on morphological analyzes obtained with light and transmission electron microscopy, molecular data (sequencing of small subunit ribosomal DNA - SSU rDNA), and phylogenetic analyses. The species studied here develops plasmodia with a worm-like shape endowed with motility. The myxospores of Ceratomyxa sp. were elongated, with rounded ends, having its interior composed of binucleated sporoplasm, and two polar capsules of equal size harboring polar tubules with 3 coils. The ultrastructural analysis showed different stages of plasmodial development in the hosts gallbladder, and different stages of sporogonic development inside the plasmodia. The sequencing of the SSU rDNA resulted in a sequence of 1448 base pairs that does not match to any sequence of myxosporid species available on GenBank. Phylogenetic analysis revealed the formation of a clade composed of freshwater species of the genus Ceratomyxa, where Ceratomyxa sp. parasite of R. vulpinus araised as a sister species of Ceratomyxa vermiformis. With the morphological and molecular data here obtained, it is possible to conclude that Ceratomyxa sp. is a species yet not described in literature.
Fish from the Amazon Basin are host of several parasites, such as the cnidarians of the Class Myxozoa (myxozoans), with approximately 2600 described species. Within the myxozoans we highlight the species of the genus Ceratomyxa Thélohan, 1892, that infect majority marine fishes, but in recent studies have been described several new species parasitizing South American freshwater fish. In this work, a freshwater species of Ceratomyxa species parasitizing the gallbladder of Rhaphiodon vulpinus Spix & Agassiz, 1829 (Characiformes: Cynodontidae) from Tapajós river, Pará state, Brazil is described. Its characterization was based on morphological analyzes obtained with light and transmission electron microscopy, molecular data (sequencing of small subunit ribosomal DNA - SSU rDNA), and phylogenetic analyses. The species studied here develops plasmodia with a worm-like shape endowed with motility. The myxospores of Ceratomyxa sp. were elongated, with rounded ends, having its interior composed of binucleated sporoplasm, and two polar capsules of equal size harboring polar tubules with 3 coils. The ultrastructural analysis showed different stages of plasmodial development in the hosts gallbladder, and different stages of sporogonic development inside the plasmodia. The sequencing of the SSU rDNA resulted in a sequence of 1448 base pairs that does not match to any sequence of myxosporid species available on GenBank. Phylogenetic analysis revealed the formation of a clade composed of freshwater species of the genus Ceratomyxa, where Ceratomyxa sp. parasite of R. vulpinus araised as a sister species of Ceratomyxa vermiformis. With the morphological and molecular data here obtained, it is possible to conclude that Ceratomyxa sp. is a species yet not described in literature.
Descrição
Citação
Franzolin, Gustavo Negrão Taxonomia e sistemática de Ceratomyxa sp. (Cnidaria: Myxozoa), parasito de Rhaphiodon vulpinus (Characiformes: Cynodontidae) da Bacia Amazônica / Gustavo Negrão Franzolin. – – Diadema, 2021. 49 f. Dissertação (Mestrado em Ecologia e Evolução) - Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, 2021.