Orientador: Edson Aparecido Adriano / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T12:26:07Z (GMT). No. of bitstreams: 1 Naldoni_Juliana_D.pdf: 10311500 bytes, checksum: a497c164e89d09cfdbe8ccfcf87ef274 (MD5) Previous issue date: 2014 / Resumo: Mixosporídeos são cosmopolitas e infectam peixes em diversas regiões do mundo. Atualmente são conhecidas cerca de 2.400 espécies, das quais a grande maioria é parasito de peixes, tanto de ambiente natural como de sistemas de criação, sendo algumas espécies responsáveis por altas taxas de mortalidade em várias partes do mundo. Este trabalho teve como objetivo o estudo da diversidade de mixosporídeos parasitos de Pseudoplatystoma corruscans (pintado), Salminus franciscanus (dourado) e Brycon orthotaenia (matrinxã) da bacia do rio são Francisco, município de Pirapora, MG, Brasil. Foram realizados estudos morfológicos, ultraestruturais, histotológicos e moleculares de cinco novas espécies de mixosporídeos, sendo uma do gênero Henneguya em pintado, duas do gênero Myxobolus infectando dourado e duas infectando matrinxã. Henneguya sp. n. 1 apresentou plasmódios brancos e alongados no tecido conjuntivo das brânquias de pintado. A análise ultraestrutual revelou a parede plasmodial com delicadas projeções em direção aos tecidos do hospedeiro e a presença de uma fina camada de material finamente granular isolando o parasito do contato com o tecido do hospedeiro. A análise histológica revelou que o desenvolvimento do plasmódio causou a compressão no tecido conjuntivo e epitelial, deformação dos filamentos e a fusão lamelar. A análise filogenética, baseada no gene 18S rDNA e utilizando somente espécies dos gêneros Henneguya e Myxobolus parasitos de siluriformes, revelou o agrupamento de acordo com a família dos peixes hospedeiros. Myxobolus sp. n. 1 apresentou plasmódios brancos e arredondados entre os raios da nadadeira de dourado. A análise ultraestrutural revelou uma camada de fibroblastos circundando o plasmódio, impedindo o contato com as células do hospedeiro. Myxobolus sp. n. 2 apresentou plasmódios brancos e arredondados no fígado de dourado. Myxobolus sp. n. 3 e Myxobolus sp. n. 4 apresentaram plasmódios brancos e arredondados, sendo que a primeira ocorreu no baço e a segunda no rim de matrinxã. A análise ultraestrutural de Myxobolus sp. n. 2, Myxobolus sp. n. 3 e Myxobolus sp. n. 4 revelou o contato direto entre a parede do plasmódio do parasito e o tecido dos hospedeiros. As paredes dos plasmódios das cinco espécies aqui estudadas foram compostas por membrana simples. O processo de esporogênese das cinco espécies foi assincrônico, com células germinativas e jovens estágios de desenvolvimento dos esporos ocorrendo na periferia do plasmódio e esporos imaturos e maduros foram observados na região central. A análise filogenética, baseado no gene 18S rDNA e usando somente espécies dos gêneros Henneguya e Myxobolus parasitos de peixes da América do Sul mais as quatro novas espécies de Myxobolus parasitas de briconídeos, mostrou a especificidade de hospedeiro e a afinidade de órgão/tecido, como um importante sinal evolutivo para Myxobolus/Henneguya / Abstract: Myxosporeans are cosmopolitan parasites and infect fish in various regions of the world. So far, are known about 2,400 species, of which the vast majority are parasites of fishes, from natural environment and fish farms, and some species responsible for high mortality rates in various parts of the world. This work aimed to study the diversity of myxosporeans of Pseudoplatystoma corruscans (pintado), Salminus franciscanus (dourado) and Brycon orthotaenia (matrinxã) from the São Francisco River, municipality of Pirapora, MG, Brazil. Morphological, ultrastructural, histological and molecular studies of five new species of myxosporeans were performed, being one species of the genus Henneguya infecting pintado, two of the genus Myxobolus infecting dourado and two infecting matrinxã. Henneguya sp. n. 1 had white and elongated plasmodia in the connective tissue of the gill filaments. The ultrastructural analysis revealed the plasmodial wall with delicate projections towards the tissues of the host, and the presence of a thin layer of fibrous material isolating the parasite of the contact with the host tissue. Histological analysis revealed that the development of the plasmodium caused compression of the connective and epithelial tissue, deformation of the filament and lamellar fusion. Phylogenetic analysis, based on 18S rDNA gene, and using only Henneguya and Myxobolus parasites of siluriformes revealed clustering according to the family of the host fish. Myxobolus sp. n. 1 had white and rounded plasmodia that developed between the fin rays of dourado. The ultrastructural analysis showed a fibroblast layer surrounding the plasmodium, preventing contact of the parasite with the host tissues. Myxobolus sp. n. 2 had white and rounded plasmodia that developed in the liver also of dourado. Myxobolus sp. n. 3 and Myxobolus sp. n. 4 infected matrinxã, being that the first had white and rounded plasmodia in the spleen and the second in the kidney. The ultrastructural analyses of Myxobolus sp. n. 2, Myxobolus sp. n. 3 and Myxobolus sp. n. 4 revealed direct contact between the plasmodial wall and the host tissue. The plasmodial wall of the five myxosporeans species subject of this study was composed by single membrane. The process of sporogenesis in these five species was asynchronous, with germ cells and young development stages of spores occurring in the periphery of the plasmodia and immature and mature spores in the central region. Phylogenetic analysis based on 18S rDNA gene and using only Henneguya and Myxobolus parasites of fish from South America plus the four new Myxobolus species parasites of bryconids, shows host specificity and organs/tissue affinity as important evolutionary signs to Myxobolus/Henneguya / Doutorado / Parasitologia / Doutora em Parasitologia

Mixosporídeos apresentam ampla distribuição geográfica e infectam principalmente peixes e invertebrados. Até o momento foram descritas aproximadamente 2.400 espécies. No entanto, para a América do Sul, onde se encontra a maior diversidade ictiofaunística, ainda existem poucos estudos. Esse estudo foi desenvolvido na Bacia do rio São Francisco a qual possui uma extraordinária ictiofauna com aproximadamente 158 espécies descritas. Entre estas, algumas espécies como aquelas da família Bryconidae merecem destaque pela importância econômica na pesca extrativista e potencial de cultivo. As analises morfológicas (microscopia de luz e análise ultraestrutural), biologia molecular (PCR e sequenciamento) foram utilizadas para descrever duas espécies novas de Myxobolus encontradas infectando um bryconídeo endêmicos do Rio São Francisco popularmente conhecido como matrinxã (Brycon orthotaenia). Myxobolus sp.1 foi encontrada no ovário e Myxobolus sp. 2 no fígado de B. orthotaenia. O estudo da interação parasito-hospedeiro permitiu a análise do processo de desenvolvimento do parasito e como interage com o hospedeiro. O estudo taxonômico foi realizado a partir da análise morfológica, utilizando microscopia de luz, microscopia eletrônica de transmissão e análise molecular através do sequenciamento do 18s rDNA. A análise filogenética também foi realizada. / Mixosporids have a wide geographical distribution and mainly infect fish and invertebrates. So far approximately 2,400 species have been described. However, for South America, where the greatest ichthyofaunistic diversity is found, there are still few studies. This study was developed in the São Francisco river basin where an extraordinary ichthyofauna has been reported with approximately 158 species described. Among these, some species such as the ones in the Bryconidae family deserve special attention because of their economic importance for extractive fisheries and potential for farming. Morphological analyses (light microscopy and ultrastructural analysis), molecular biology (PCR and sequencing) were used to describe two new species of Myxobolus found infecting an endemic bryconid, Brycon orthotaenia known as matrinxã, from São Francisco River. Myxobolus sp.1 was found in the ovary and Myxobolus sp. 2 in the liver of B. orthotaenia. The study of host-parasite interaction allowed an analysis of the developmental process of the parasite and how it interacts to the host. The taxonomic study was done by morphological analysis, using light microscopy, transmission electron microscopy and the molecular analysis was done through the sequencing of the 18S rDNA. The phylogenic tree was also performed.

Mixosporídeos apresentam ampla distribuição geográfica e infectam principalmente peixes e invertebrados. Até o momento foram descritas aproximadamente 2.400 espécies. No entanto, para a América do Sul, onde se encontra a maior diversidade ictiofaunística, ainda existem poucos estudos. Esse estudo foi desenvolvido na Bacia do rio São Francisco a qual possui uma extraordinária ictiofauna com aproximadamente 158 espécies descritas. Entre estas, algumas espécies como aquelas da família Bryconidae merecem destaque pela importância econômica na pesca extrativista e potencial de cultivo. As analises morfológicas (microscopia de luz e análise ultraestrutural), biologia molecular (PCR e sequenciamento) foram utilizadas para descrever duas espécies novas de Myxobolus encontradas infectando um bryconídeo endêmicos do Rio São Francisco popularmente conhecido como matrinxã (Brycon orthotaenia). Myxobolus sp.1 foi encontrada no ovário e Myxobolus sp. 2 no fígado de B. orthotaenia. O estudo da interação parasito-hospedeiro permitiu a análise do processo de desenvolvimento do parasito e como interage com o hospedeiro. O estudo taxonômico foi realizado a partir da análise morfológica, utilizando microscopia de luz, microscopia eletrônica de transmissão e análise molecular através do sequenciamento do 18s rDNA. A análise filogenética também foi realizada. / Mixosporids have a wide geographical distribution and mainly infect fish and invertebrates. So far approximately 2,400 species have been described. However, for South America, where the greatest ichthyofaunistic diversity is found, there are still few studies. This study was developed in the São Francisco river basin where an extraordinary ichthyofauna has been reported with approximately 158 species described. Among these, some species such as the ones in the Bryconidae family deserve special attention because of their economic importance for extractive fisheries and potential for farming. Morphological analyses (light microscopy and ultrastructural analysis), molecular biology (PCR and sequencing) were used to describe two new species of Myxobolus found infecting an endemic bryconid, Brycon orthotaenia known as matrinxã, from São Francisco River. Myxobolus sp.1 was found in the ovary and Myxobolus sp. 2 in the liver of B. orthotaenia. The study of host-parasite interaction allowed an analysis of the developmental process of the parasite and how it interacts to the host. The taxonomic study was done by morphological analysis, using light microscopy, transmission electron microscopy and the molecular analysis was done through the sequencing of the 18S rDNA. The phylogenic tree was also performed.

The Malacosporea and Sphaerospora sesnsu stricto clade are the two most basal myxozoan clades. While the evolutionary older malacosporeans possess unique features resembling cnidarians, sphaerosporids are known for special developmental features and unique long insertions in the small and large subunits of the ribosomal DNA. This thesis aimed at elucidating the hidden biodiversity, describing special biological traits and tracing the evolutionary history of these two clades based on both, morphological and molecular data. Host-parasite phylogenetic congruence was studied to understand the evolutionary patterns of cospeciation and host switching.

Proliferative kidney disease (PKD) poses a high financial burden upon the freshwater salmonid aquaculture industry of Europe and North America. The alternate hosts of the causative agent, Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea), have been identified as freshwater bryozoans (Bryozoa: Phylactolaemata) within which spores capable of infecting salmonid fish develop. Currently, control of PKD relies upon complex management practices, with no licensed prophylaxis or treatment available. Assessment of the nutritional preferences of phylactolaemate bryozoans allowed development of an optimised laboratory culture system. Following laboratory maintenance, bryozoans collected from PKD-endemic sites were found to be infected with the malacosporean parasites T. bryosalmonae and Buddenbrockia plumatellae. Subsequent parasitic development was observed using light-, electron- and confocal-microscopy techniques. Methods of challenging rainbow trout with T. bryosalmonae spores were developed, with the minimum infective dose established. The presence of Thomsen-Friedenreich and Tn epitopes within the parasite was investigated, and experimental vaccine preparations based on either these specificities or T. bryosalmonae-infected bryozoans were efficacy tested in rainbow trout. In addition, salinomycin and amprolium were tested as prospective chemotherapeutants for PKD. Further insights into the development and subsequent release of malacosporean spores within their invertebrate hosts have been revealed. Long-term maintenance of T. bryosalmonae allowed controlled infection of rainbow trout previously vaccinated with experimental preparations. Findings of the project could potentially be utilised in future research into the development of control methods for PKD.

Thesis (Ph.D.)--Mississippi State University. Department of Basic Sciences. / Title from title screen. Includes bibliographical references.

This thesis is focused on the assessment of the phylogenetic position of the Myxozoa within the Metazoa, study of the evolutionary relationships within myxosporeans and investigation into the cryptic species assemblages of several myxosporeans based on the ribosomal and protein-coding data. The major part of this work was to confirm the evolutionary trends within myxosporeans based on a single gene by other molecular markers in order to find out if the reconstructed relationships correspond to the real organismal phylogeny. This has been a crucial step for future actions in solving the discrepancies between the myxosporean phylogeny and taxonomy.