This study is ecological in objective; primarily it attempts to evaluate environmental factors limiting the distribution of a wide-ranging species of fish, Gasterosteus aculeatus, in one sector of its holarctic range. Two approaches to this investigation are made: comparative and deductive. The comparative method is possible because many studies have been made on temperate-zone populations of the species; modified behaviour observed in the present study are consequently viewed as probably adaptive to the different environmental conditions of the north. [...]

Bibliography: leaves 219-229. / Microfiche. / xiv, 229 leaves, bound ill. 29 cm

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 145-153).

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As sequências dos genes dmrt1 e sox9 em pirarucu (Arapaima gigas), lambari (Astyanax altiparanae) e piapara (Leporinus elongatus) foram analisadas por técnicas de clonagem molecular. Fragmentos do gene dmrt1 foram clonados nas três espécies citadas, e do gene sox9 em lambari e piapara. A análise filogenética destes genes mostrou concordância com os dados morfológicos da filogenia destas espécies. Pelo acompanhamento do desenvolvimento gonadal de lambari por microscopia de luz, foi constatada a presença de células germinativas na região da futura gônada já no período de 5 dias após eclosão (dae), sendo também observado que a formação de ovário ocorre primeiro do que a formação de testículo. As expressões dos genes dmrt1 e sox9 por qRT-PCR em lambari mostraram maior especificidade para testículo do que para ovário, indicando que possivelmente estes genes ainda possuem função macho-específica nos adultos. Em lambari, os genes foram expressos em todos os períodos larvais, tendo uma diminuição no estágio de 12 dae, e aumentando sua expressão no estágio de 33 dae. / The sequences of dmrt1 and sox9 genes were analyzed in pirarucu (Arapaima gigas), lambari (Astyanax altiparanae) and piapara (Leporinus elongatus) using molecular cloning techniques. Fragments of dmrt1 gene were cloned in these three species, and sox9 gene fragments have been acquired only for lambari and piapara. Phylogenetic analysis of the genes was shown to be consistent with the morphological phylogeny of these species. The analysis of the gonadal development in lambari was followed by light microscopy, where it was found the presence of germ cells in the region of the future gonad in 5 days after hatching (dah), and that the formation of ovaries occurs first comparing to the formation of testis. The gene expression of dmrt1 and sox9 by qRT-PCR method show specificity for testis comparing to ovary, which indicates that these genes also have a male-specific role in the adult. In lambari, the genes were expressed in all larval periods, with a decrease of expression levels in 12 dah, and increasing its expression at stage of 33 dah.

As sequências dos genes dmrt1 e sox9 em pirarucu (Arapaima gigas), lambari (Astyanax altiparanae) e piapara (Leporinus elongatus) foram analisadas por técnicas de clonagem molecular. Fragmentos do gene dmrt1 foram clonados nas três espécies citadas, e do gene sox9 em lambari e piapara. A análise filogenética destes genes mostrou concordância com os dados morfológicos da filogenia destas espécies. Pelo acompanhamento do desenvolvimento gonadal de lambari por microscopia de luz, foi constatada a presença de células germinativas na região da futura gônada já no período de 5 dias após eclosão (dae), sendo também observado que a formação de ovário ocorre primeiro do que a formação de testículo. As expressões dos genes dmrt1 e sox9 por qRT-PCR em lambari mostraram maior especificidade para testículo do que para ovário, indicando que possivelmente estes genes ainda possuem função macho-específica nos adultos. Em lambari, os genes foram expressos em todos os períodos larvais, tendo uma diminuição no estágio de 12 dae, e aumentando sua expressão no estágio de 33 dae. / The sequences of dmrt1 and sox9 genes were analyzed in pirarucu (Arapaima gigas), lambari (Astyanax altiparanae) and piapara (Leporinus elongatus) using molecular cloning techniques. Fragments of dmrt1 gene were cloned in these three species, and sox9 gene fragments have been acquired only for lambari and piapara. Phylogenetic analysis of the genes was shown to be consistent with the morphological phylogeny of these species. The analysis of the gonadal development in lambari was followed by light microscopy, where it was found the presence of germ cells in the region of the future gonad in 5 days after hatching (dah), and that the formation of ovaries occurs first comparing to the formation of testis. The gene expression of dmrt1 and sox9 by qRT-PCR method show specificity for testis comparing to ovary, which indicates that these genes also have a male-specific role in the adult. In lambari, the genes were expressed in all larval periods, with a decrease of expression levels in 12 dah, and increasing its expression at stage of 33 dah.

Three new NILT genes were successfully cloned and characterized from rainbow trout, with one NILT alternatively spliced into a long isoform containing two Ig domains and a short isoform containing one Ig domain.  The expression of NILTs was studied in six different tissues and two different cell lines, with expression apparent in immunologically important tissues.  Furthermore, phylogenetic analysis showed that NILTs are more closely related to triggering receptor expressed on myeloid (TREM) cells and Nkp44 from humans than to NITRs from rainbow trout. The genomic organisation and structure of the multigene family of NILTs in Atlantic salmon was investigated using a BAC sequencing approach.  This revealed the presence of six novel NILT genes, which either contained one or two Ig domains and several immunoreceptors tyrosine-based inhibitory motifs (ITIMs) in the cytoplasmic region. By homology search two NILT-like genes in zebrafish (<i>Danio rerio</i>) located on chromosome 1 have been obtained. Chromosome 1 in zebrafish also contains the <i>Dare</i>-ZE genes, which are equivalent to the human MHC class I genes located on chromosome 6.  The distance between the later and the TREM genes on chromosome 6 is similar to the distance between the NILT-like genes and <i>Dare</i>-ZE genes on zebrafish chromosome 1.  In addition, two NILT-like Ig domains were obtained from the green spotted pufferfish (<i>Tetraodon nigroviridis</i>), putatively part of the same receptor. The results will contribute to our knowledge of the immune system in fish and provide useful information for the control of inflammatory processes in salmonids.

Graduation date: 1982

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy