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| Author(s): |
Tiago Milanin
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-04-08 |
| Examining board members: |
Edson Aparecido Adriano;
Edilson Rodrigues Matos;
Marlene Tiduko Ueta;
Rodney Kozlowiski de Azevedo;
Eduardo Makoto Onaka
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| Advisor: | Edson Aparecido Adriano |
| Abstract | |
Among the fish parasites, those of the Myxozoa phylum are highlighted as the most important. Most species of myxozoans show life cycle that involves two development stages, being that in vertebrates, mainly in annelids, occurs the actinospore stage and in vertebrates, mainly in fishes, but also in amphibians, reptiles, birds and mammals, the myxospore stage. In this study, morphological and molecular analysis were performed in actinospore and myxospore stages found in oligochaetes and fishes from fish farms from São Paulo and Mato Grosso do Sul states. For the actinosporo study, were performed two oligochaetes gatherings in two fish farms, one located in municipality of Porto Ferreira, São Paulo state and other in municipality of Terenos, Mato Grosso do Sul state. Of the 333 oligochaetes collected in Porto Ferreira, 13 (3.9%) specimen of Pristina americana were observed releasing four actinospore types, being Aurantiactinomyxon types 1, 2 and 3, and Helioactinomyxon type 1. The ultrastructural analysis performed in one specimen of P. americana showed two different developmental stages of pansporocysts of Aurantiactinomyxon type 2 in the gut wall. In Terenos, 86 specimens of oligochaetes were collected, being that one specimen (0.9%) identified as Slavina evelinae was releasing actinospore of Seisactinomyxon type 1 nov., which belongs to collective group still not reported in the literature. The oligochaetes identification was performed based on morphological data and on the 18S rDNA sequencing. The sequencing of the 18S rDNA of Aurantiactinomyxon types 1 and 2, and Seisactinomyxon type 1 nov. were also performed, resulting in partial sequences containing 1200, 902 and 1877pb, respectively. The phylogenetic analysis showed that Aurantiactinomyxon type 1 and 2, and Seisactinomyxon type 1 nov. have grouped in a clade with a Thelohanellus species parasite of Siluriformes and other six species of Myxobolus parasites of Characiforms fishes. In the mixospore study, specimens of patinga (hybrid resulted from a cross between Piaractus mesopotamicus and P. brachypomus) and pintado (hybrid resulted from a cross between Pseudoplatystoma corruscans and P. reticulatum), were gathered from two fish farms in São Paulo state. From 15 specimens of patinga collected in Porto Ferreira, 11 (73.3%) presented Myxobolus cf. cuneus infection, and from the 20 specimens of hybrid pintado collected in Mogi Mirim, eight (40%) showed Henneguya pseudoplatystoma infection. The 18S rDNA sequencing of M. cf. cuneus and H. pseudoplatystoma spores resulted in sequences containing 1855 and 1946 bp, respectively. The M. cf. cuneus ultrastructural analysis revealed that the plasmodium presented an asynchronous development, with the presence of disporic pansporoblasts in two different development phase, and immature and mature spores in the whole plasmodium. The phylogenetic analysis showed M. cf cuneus as a sister specie of H. pellucida, in a subclade mainly composed of myxozoans parasites of Characiforms and H. pseudoplatystoma grouped in a subclade composed of Henneguya spp. parasites of fish of Pseudoplatystoma genus (AU) | |
| FAPESP's process: | 11/08549-6 - Evaluation of the involvement of invertebrate hosts in the life cycle of Myxozoa parasites of pintado (including hybrids) and pacu (including hybrids) from fish farm. |
| Grantee: | Tiago Milanin |
| Support Opportunities: | Scholarships in Brazil - Doctorate |