Mariliasuchus amarali Carvalho & Bertini 1999 é um crocodilomorfo Notosuchia do Cretáceo da Bacia Bauru. Este táxon possui um registro fóssil relativamente comum, e diversos espécimes (incluindo animais juvenis) são conhecidos. Portanto, ele representa um dos poucos táxons fósseis que permitem uma análise ontogenética, e seu desenvolvimento foi comparado com o do gênero Caiman (incluindo C. latirostris, C. crocodilus e C. yacare), um crocodilomorfo atual de ampla distribuição pela América do Sul. Foram empregadas as seguintes metodologias para comparação das trajetórias ontogenéticas dos táxons fóssil e atual: descrição qualitativa, morfometria linear e morfometria geométrica. Os dados obtidos destacaram trajetórias ontogenéticas comuns aos dois táxons, que foram interpretadas como o resultado de um padrão plesiomórfico aos Crocodyliformes, e distintas trajetórias ontogenéticas que foram relacionadas, principalmente, a diferentes adaptações ecomorfológicas. A ocorrência de tendências ontogenéticas como a manutenção de uma fenestra supratemporal de grandes proporções ao longo da ontogenia, a expansão anterior do articular e do côndilo mandibular do quadrado, o aumento na espessura da camada de esmalte dentário e a alometria positiva das fenestras infratemporal e mandibular sugerem que Mariliasuchus amarali aumentava gradativamente seu controle e capacidade de processamento alimentar ao longo de seu desenvolvimento. A análise ontogenética também mostrou fortes evidências de que o espécime UFRJ-DG 56-R, interpretado por Nobre et al. (2007a) como uma nova espécie dentro do gênero Mariliasuchus (M. robustus), é na verdade um indivíduo de M. amarali em avançado estágio de desenvolvimento e não uma nova espécie. O espécime MZSP-PV 760 é descrito pela primeira vez no presente trabalho. Suas características anatômicas sugerem que o mesmo não é um indivíduo juvenil de Mariliasuchus, como pensado anteriormente, mas parece estar relacionado ao clado que inclui ambos M. amarali e Adamantinasuchus navae (outro crocodilomorfo da Bacia Bauru). MZSP-PV 760 representa o mais jovem crocodilomorfo pós-embrionário já descrito para o Cretáceo de Gondwana. Uma reanálise da dentição altamente heterodonte em M. amarali mostrou a ocorrência de um novo morfótipo dentário (pré-molariforme), descrito pela primeira vez no presente trabalho. Uma coroa de cada morfótipo dentário foi extraída do espécime MZSP-PV 813 para análise da microanatomia do esmalte dentário e do padrão de organização dos cristais de esmalte, descritos pela primeira vez para um Notosuchia. A descrição de um novo morfótipo dentário representa uma inesperada adição para uma já complexa condição heterodonte em M. amarali, corroborando com a hipótese de OConnor et al. (2010) de que os Notosuchia podem ter ocupado nichos ecológicos e ecomorfoespaços, durante o Cretáceo do Gondwana, tão complexos quanto os de mamíferos. / Mariliasuchus amarali Carvalho & Bertini 1999 is a notosuchian crocodyliform from the Cretaceous of Bauru Basin (Brazil). This taxon has a fossil record that is relatively common, and several specimens (including juveniles) are known. Therefore, it represents one of the few fossil taxa that allows an ontogenetic approach, and its development was compared with the genus Caiman (including C. latirostris, C. crocodilus and C. yacare), a widespread South American crocodyliform. I used the following methodologies for the comparison of the ontogenetic trajectories of the fossil and living taxa: qualitative description, traditional morphometrics and geometric morphometrics. The data highlighted common ontogenetic trajectories that were interpreted as the result of a plesiomorphic pattern for Crocodyliformes, and distinct ontogenetic trajectories that were related mainly to different ecomorphological adaptations. The occurrence of ontogenetic trends as the retention of a large supratemporal fenestra along the ontogenetic development, the anterior expansion of the articular and the articular condyle of the quadrate, the thickening of the enamel cap in the teeth crowns, and the positive allometry of both infratemporal and mandibular fenestrae, suggest that Mariliasuchus amarali gradually increased its control and capacity of food processing along its ontogeny. The ontogenetic analysis also provided compeling evidence that specimen UFRJ-DG 56-R, interpreted by Nobre et al. (2007a) as a new species of the genus Mariliasuchus (M. robustus), is actually an individual of M. amarali in an advanced stage of development rather than a new species. Specimen MZSP-PV 760 is described for the first time here. Its anatomical characteristics suggest that this individual is not a juvenile specimen of Mariliasuchus amarali, as previously thought, but rather appears to be related to the clade that includes both M. amarali and Adamantinasuchus navae (another Bauru Basin crocodyliform). MZSP-PV 760 represents the youngest post-hatchling crocodyliform described for the Cretaceous of Gondwana. A reevaluation of the highly heterodont dentition of M. amarali showed the occurrence of a new tooth morphotype (premolariform), described here for the first time. A crown from each tooth morphotype was extracted from the specimen MZSP-PV 813 to perform an analysis of the enamel microanatomy and organizational patterns of enamel crystallities, described for the first time within Notosuchia. The description of a new tooth morphotype represents an unexpected addition to an already complex heterodont condition in M. amarali, adding to OConnor et al.s (2010) hypothesis that Notosuchia could have filled complex niches and ecomorphospaces during the Cretaceous of Gondwana similar to the ones occupied by mammals.

Analisamos o efeito do sistema serotoninérgico no desenvolvimento somático e na ontogênese de reflexos dos filhotes, cujas mães foram submetidas a tratamento farmacológico durante a prenhez. Ratas wistar prenhas foram divididas em dois grupos (N=11): Grupo AD, tratadas com água destilada, Grupo Sert, tratadas com sertralina 30mg/kg, 0,5mL/100g, s.c. Um dia após o parto 8 neonatos (4 machos e 4 fêmeas) foram mantidos com suas mães do 1º ao 21º dia pós-natal. O investigador cego avaliou o crescimento somático, características físicas e maturação de reflexos. Aos 22 e 60 dias de idade os encéfalos foram processados com técnicas de imunoistoquímica contra 5-HT. O grupo Sert, macho ou fêmea, apresentou atraso no crescimento somático e na maturação de alguns reflexos. A quantidade de neurônios 5-HT-IR foi alterada nos núcleos da rafe nos ratos aos 22 dias de idade, mas não aos 60 dias. A análise da morfometria dos neurônios 5-HT-IR, em ambas as idades estudadas, revelou alterações em sua forma. Os resultados deste estudo demonstram a ação inibitória da serotonina sobre o crescimento somático e desenvolvimento sensório-motor bem como alterações na quantidade e na forma dos neurônios 5-HT em ratos. / The aim of the present study was to investigate the effects of prenatal sertraline exposure on offspring in growth and somatic development and even in the maturation of reflex in rats. Female wistar rats were treated with sertraline (Sert, 30 mg/kg, 0,5 mL/100 g, s.c., N=11) or distilled water (Control, N=11) during the whole pregnancy. After the birth, 8 pups (4 males and 4 females) were kept in each litter during lactation. The blind investigator evaluated indicators of general body growth parameters, somatic maturation and ontogeny of reflex during the period of lactation. The central nervous system alterations were approached by 5-HT-IR using the ABC-DAB-Peroxidase techniques in animals at the 22st and 60st postnatal day. The Sert group, showed reduction on the somatic growth and on the maturation of reflexes. There was reduction in the amount of the 5-HT-IR neurons in the raphe nuclei at the 22st postnatal day, but did not change at the 60st. The morphometric analysis revealed alterations in the shape of these cells at the 22st and 60st postnatal day. An inhibitory action of the 5-HT on the somatic and sensory-motor growth in these rats was also observed. After the lactation period, the amount and shape of the 5-HT neurons were altered.

O conhecimento dos estágios iniciais do desenvolvimento embrionário de peixes é de extrema importância para o estudo de espécies nativas com potencial para a piscicultura, uma vez que permite o estabelecimento de diretrizes para a criação destes animais. Este projeto estudou o desenvolvimento embrionário da piapara (Leporinus elongatus), um peixe de grande importância na pesca esportiva e profissional na bacia dos rios Pardo e Jequitinhonha, visando compreender as fases desse animal em diversos estágios de desenvolvimento, utilizando marcadores ósseos que possibilitaram visualizar o desenvolvimento ósseo da espécie. As Proteínas Ósseas Morfogenéticas (BMP-2 e BMP-4) são consideradas moléculas essenciais reguladoras no desenvolvimento embrionário e na formação óssea, sendo ainda pouco estudadas em peixes; tais proteínas puderam ser observadas apenas no estádio larval até o período juvenil, não sendo evidenciadas nos estágios anteriores. Foram utilizadas também técnicas de Microscopia Eletrônica de Varredura e histológicas, onde foi possível visualizar as fases principais do desenvolvimento embrionário, entre elas, clivagens, diferenciação do embrião, formação dos órgãos principais, abertura de boca, pigmentação dos olhos, surgimento das nadadeiras e sistema branquial, dados estes que facilitam a compreensão sobre a ontogenia; além de criar dados embriológicos e anatômicos dessa espécie ainda pouco explorada, conhecimentos estes, imprescindíveis à biologia pesqueira e cultivo das mesmas, sendo também um auxiliar a novas pesquisas. / The knowledge of the early stages of embryonic development in fish is of great importance for the study of native species with potential for aquaculture, since it allows the establishment of guidelines for the breeding of these animals. This project studied the embryonic development of piapara (Leporinus elongatus), a fish of great importance in professional and amateur fishing from the basin of the Pardo and Jequitinhonha rivers, aiming to understand the various stages of development, using bone markers that allowed observation of the bone development in this species. The Bone Morphogenetic Proteins (BMP-2 and BMP-4) are known as key regulatory molecules in embryonic development and bone formation, and information on this subject is scarce in fish. Results shown these proteins could be observed only between the larval to the juvenile stage, not being seen at earlier stages. Scanning electron microscopy and histological techniques, where it was possible to observe the main stages of embryonic development , including , cleavage , embryo differentiation , development of major organs , mouth opening , eye pigmentation , appearance of fins and gills system. This data contributed for the understanding of ontogeny, and provided embryological and anatomical data that may help other studies like reproductive biology of this species that surely will improve reproductive techniques, important goal for raising the piapara.

Variações ontogenéticas nas enzimas pró-coagulantes do veneno de B. jararaca filhotes (vBjF) tornam este veneno mais coagulante que o de serpentes adultas (vBjA). Além disso, o vBjF não é tão eficientemente neutralizado pelo soro antibotrópico in vitro, como o vBjA. Neste trabalho comparamos as alterações hemostáticas induzidas pelos venenos vBjA e vBjF em ratos e avaliamos sua recuperação após o tratamento com soro antibotrópico (SAB), por meio de análises de tromboelastometria, dosagens de fatores de coagulação, e análise de plaquetas. Ratos Wistar machos foram inoculados com vBjA e vBjF (1,6 mg/kg , s.c.) ou solução salina (controle), e tratados com SAB ou solução salina (100 mL i.v.) 1 hora (h), após a inoculação dos venenos. Amostras de sangue de ratos tratados foram coletadas em 1, 3, 6 e 24 h após a injeção para avaliar os níveis de fibrinogênio plasmático, haptoglobina plasmática, hemoglobina plasmática, produtos de degradação de fibrinogênio e fibrina (PDF/f), complexo trombina- antitrombina III (TAT), fator de von Willebrand ( vWF), fatores de coagulação II e X , e também para contagem e análise funcional das plaquetas. Para as análises de tromboelastometria, foram coletadas amostras de sangue citratado (recalcificado) e de sangue nativo (sem anticoagulante) em 6 e 24 h após a inoculação e tratamento com solução salina ou SAB. Às amostras de sangue citratado foram adicionados reagentes específicos para analise das vias intrínseca e extrínseca da coagulação. Parâmetros como o tempo de coagulação (CT), o tempo de formação do coágulo (CFT) e ângulo alfa foram adquiridos durante 1 h. Em 3 h a contagem de plaquetas de ratos inoculados com vBjA e vBjF, e também o níveis de fibrinogênio, haptoglobina, FII, FX e vWF caíram abruptamente em relação aos controles, enquanto os de TAT e PDF/f aumentaram. Em 6 h os níveis de fibrinogênio ainda encontravam-se bastante baixos para ambos os venenos. Pela análise de tromboelastometria, notou-se que em 6 h os parâmetros CT, CFT, ângulo alfa permanecem muito alterados em ratos não tratados. Com o tratamento com SAB, todos os parâmetros foram significativamente restaurados, para ambos os grupos envenenados, principalmente em 3 e 6 horas após a inoculação venenos . Assim, apesar das diferenças entre vBjA e vBjF com relação a composição e potencial de neutralização in vitro, o tratamento com SAB foi igualmente eficiente na reversão dos distúrbios hemostáticos decorrentes do envenenamento por ambos os venenos / Ontogenetic variations in the pro-coagulant enzymes of the young B. jararaca venom (YBjv) makes it more coagulant than that from adult snakes (ABjv). Moreover, YBjv is not so efficiently neutralized by specific antivenin in vitro as ABjv. Herein we compared hemostatic disturbances induced by ABjv and YBjv in rats and assessed their recovery after treatment with botropic antivenin by thromboelastometry, dosages of coagulation factors, and platelet analysis. Male Wistar rats were inoculated with ABjv and YBjv (1.6 mg/kg, s.c), or saline (control), and treated with botropic antivenin (SAB) or saline (100 μL i.v.) 1 hour (h) after venom inoculation. Blood samples of treated rats were collected 1, 3, 6 and 24 h after injection to evaluate plasmatic fibrinogen, plasmatic haptoglobina, plasmatic hemoglobin, fibrin and fibrinogen degradation products (FfDP), thrombin-antithrombin III complex (TAT), von Willebrand factor (vWF), coagulation factors II and X, and also to count and functional analysis on platelets. Thromboelastometry was carried out on citrated (recalcified) and native (without anticoagulant) blood samples, collected 6 and 24 h after injection and treatment with SAB or saline. Citrated samples were mixed with specific reagents to analyze the intrinsic and extrinsic pathways. Parameters as clotting time (CT), clot formation time (CFT) and alpha angle were acquired for 1 h. At 3 h, platelet count of ABjv and YBjv rats and also fibrinogen, haptoglobin, FII, FX and vWF levels fell abruptly in regard to controls, while TAT and FfDP increased. At 6 h the fibrinogen levels still pretty low for both venoms. By thromboelastometry analysis, at 6 h, it was noticed that the CT, CFT, alpha angle remain greatly altered on non-treated rats. With the SAB treatment, all the parameters were significantly restored, for both envenomed groups, especially at 3 and 6 h after the venoms inoculation. Thus, despite differences in composition and in vitro neutralization potential among ABjv and YBjv, the treatment with SAB was equally efficient in reversing the hemostatic disturbances caused by both venoms

Orientador: Roberto Goitein / Banca: Leandro Muller Gomiero / Banca: Sidnei Eduardo Lima Junior / Resumo: Neste trabalho foram analisados exemplares da espécie Salminus hilarii com a finalidade de verificar as variações morfológicas que possam ocorrer ao longo da vida do peixe, juntamente com a relação massa-comprimento. Para as análises foram tomadas 19 medidas morfométricas, sendo 17 referentes a S. hilarii e duas para as presas ingeridas. Estas medidas foram utilizadas para os cálculos de três índices e 17 valores relativos de atributos morfológicos. As medidas de S. hilarii foram tomadas a partir de exemplares com uma amplitude de tamanho variando entre 50 a 450 mm no comprimento padrão. Foi feita uma comparação entre indivíduos jovens e adultos, machos e fêmeas, e em diferentes classes de comprimento relacionando tais características morfológicas com as velocidades de corrente dos locais onde vivem e o tamanho das presas ingeridas por essa espécie. As amostras para as análises foram coletadas nas bacias dos rios Sorocaba e complementadas com indivíduos depositados no acervo do Departamento de Zoologia provenientes dos rios Jacaré Pepira, Corumbataí (sub-bacia do Tietê), e Mogi Guaçu (sub-bacia do rio Grande). Na comparação entre machos e fêmeas e entre adultos e imaturos foram analisados somente indivíduos capturados no rio Sorocaba onde foi possível a determinação desses grupos. Esse trabalho mostrou que não houve variações significativas entre as sub-bacias dos rios Tietê e Grande. O mesmo foi observado entre machos e fêmeas, mostrando que não há dimorfismo sexual nas características observadas. Entre os imaturos e adultos, assim como nas diferentes classes de comprimento, nove características morfológicas não mostraram diferenças significativas. Nas demais (onze) apresentaram diferenças significativas entre pelo menos duas classes de comprimento. Complementando, foram observadas correlações significativas entre as velocidades calculadas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Salminus hilarii specimens were studied using several body measurements and relationships related to their proportions, considering mainly possible ontogenetic changes. Relationships between mass and length were analyzed as well. The usual comparisons made for studies related to distinct species was the subject of the study to compare possible changes occurring during the life of individuals of one species. For this purpose 19 morphometric measurements were obtained, but only 17 were related to individuals of the species e 2 for ingested prey. The S. hilarii measurements used individuals whose standard lengths varied from 50 to 450 mm. This study intended to compare young and adult individuals, as well as males and females. Distinct length classes were established and these data were also used to establish possible relationships between individuals who are usually caught in distinct places of the Sorocaba river, and are submitted to distinct water current effects. Larger individuals use to live in the middle of the river where water flows more rapidly, while the younger ones live near to the river margin or calm waters. Food intake may also suggest some distinct morphological aspects. So, the main organism, when almost intact were also measured. Samples for the analyses were collected at the Sorocaba basin, but were complemented with specimens collectecat the rivers Jacaré-Pepira, Corumbataí (Tietê sub-basin) and Mogi-Guaçu (Rio Grande sub-basin). These specimens are deposited at the Zoology Department (Unesp - Rio Claro). To compare males and females, only fish from the Sorocaba river were considered for analysis. The study permitted to find out that no significant differences exist for fish originated from the Tietê and Rio Grande sub-basins. The same happens for male and female individuals. When immature and adult individuals were compared nine morphological characters... (Complete abstract click electronic access below) / Mestre

Methylphenidate (MPH) is the most commonly-prescribed medication for treating ADHD. Despite high prescription rates among kindergarten-aged children, MPH was not approved for use in children younger than nine, and research into its long-term consequences is lacking. Here, we examined the effects of early-life MPH exposure on anxiety-like behaviors in adulthood in normal rats and rats with dysfunctional central dopamine. On postnatal day (PD) 3, male and female rat pups were injected intracisternally with 6-OHDA or vehicle to generate normal and dopamine-deficient groups. In an initial pair of experiments, 6-OHDA (50, 100 and 150 µg/10µL infusion) was assessed for its ability to induce an ADHD-like phenotype. Subsequently, rats were lesioned with 6-OHDA (100 µg/infusion) or vehicle on PD3 and given MPH (0, 0.5, 2 or 5 mg/kg, i.p.) once daily for 10 days, starting on PD11. On PD60, anxiety-like behavior was assessed with light/dark box or social interaction tests. On PD65, all rats were tested on the elevated plus maze (EPM). Rats with neonatal 6-OHDA lesions exhibited anxiety-like behavior in the light/dark box test and on the EPM. However, there was a complex interaction between sex, lesion, and drug dose in the social interaction test. Pretreatment with 2 mg/kg MPH increased investigatory behaviors in non-lesioned females and decreased investigatory behaviors in lesioned females, suggesting that the long-term effects of early-life MPH in females depend on normal dopamine levels. Together, these experiments support the efficacy of preclinical ADHD models and diverse measures of anxiety-like behaviors when studying the effects of early-life MPH exposure.

As a comparison to the suction feeding mechanics in aquatic environments, I investigated buccal pumping in an ontogenetic series of suspension feeding Xenopus laevis tadpoles (4-18 mm snout-vent length) by examining the morphology, kinematics, fluid flow, pressure generated in the buccal cavity, and effects of viscosity manipulation. Investigation of the dimensions of the feeding apparatus of Xenopus revealed that the feeding muscles exhibited strong negative allometry, indicating that larger tadpoles had relatively smaller muscles, while the mechanical advantage of those muscles did not change across the size range examined. Buccal volume and head width also exhibited negative allometry: smaller tadpoles had relatively wider heads and larger volumes. Tadpoles were imaged during buccal pumping to obtain kinematics of jaw and hyoid movements as well as fluid velocity. Scaling patterns were inconsistent with models of geometric growth, which predict that durations of movements are proportional to body length. Only scaling of maximum hyoid distance, duration of mouth closing, and duration of hyoid elevation could not be distinguished from isometry. The only negatively allometric variable was maximum gape distance. No effect of size was found for duration of mouth opening, duration of hyoid depression, and velocity of hyoid elevation. Velocity of mouth opening, velocity of mouth closing, and velocity of hyoid depression decreased with increasing size. Fluid velocity increased with size, and is best predicted by a piston model that includes head width and hyoid depression velocity. Reynolds number increased with size and spanned two flow regimes (laminar and intermediate) ranging from 2 to over 100. Pressure was found to be greatest in the smallest tadpoles and decreased as size increased, ranging from 2 kPa to 80 kPa. The viscosity of the water was altered to explore changes in body size, independent of development (higher viscosity mimicked smaller tadpole size). Viscosity manipulations had a significant effect on the kinematics. Xenopus initially increased velocity and distance of movements as viscosity increased, but these values declined as viscosity increased further. These results suggest that abiotic factors such as fluid viscosity may set a lower size limit on suspension feeding.

Les poissons demoiselles (Pomacentridae) représentent lune des familles les plus importantes des récifs coralliens ; du point de vue du nombre despèces (> 350) et de leur abondance. Malgré cette importance, très peu détudes ont abordé leur diversité trophique et morphologique. Comme la majorité des poissons coralliens, les demoiselles possèdent un cycle de vie complexe divisé en deux phases : (1) une phase larvaire pélagique et océanique potentiellement dispersive et (2) une phase juvénile et adulte sédentaire associée à lhabitat corallien. La fin du stade larvaire coïncide avec la colonisation du récif. Le milieu océanique offre un habitat relativement homogène pour toutes les larves de Pomacentridae et celles-ci se nourrissent exclusivement de copépodes planctoniques. Au contraire, le récif propose une grande variété dhabitats et de ressources alimentaires. Au cours de leur ontogénie, les demoiselles subissent donc un changement de mode de vie qui doit saccompagner de modifications morphologiques, physiologiques et comportementales pour optimiser leur survie dans chaque environnement. La présente thèse a pour premier objectif de tester lhypothèse selon laquelle la plus grande diversité trophique attendue au stade adulte saccompagne dune plus grande disparité (mesure de la diversité morphologique au sein dun taxon) que chez les larves. Répondre à cet objectif a nécessité dorganiser la recherche selon trois axes. Premièrement, Lanalyse des contenus stomacaux et des isotopes stables du carbone et de lazote chez treize espèces a permis de mettre en évidence trois comportements alimentaires : (1) les « pelagic feeders » qui se nourrissent presquexclusivement de copépodes planctoniques, (2) les « benthic feeders » qui sont des espèces principalement herbivores broutant des algues filamenteuses et (3) un groupe intermédiaire incluant des espèces qui se nourrissent en proportions variables dans le compartiment pélagique et benthique (ex : copépodes planctoniques et benthiques, petits invertébrés vagiles et sessiles, algues filamenteuses). La littérature signale en plus deux demoiselles spécialisées dans la consommation exclusive de polypes de coraux. Deuxièmement, une étude écomorphologique a caractérisé la diversité du squelette céphalique chez les adultes. Les variations de forme de quatre unités du squelette céphalique (le neurocrâne, lunité « suspensorium et opercule », la mandibule et le prémaxillaire) ont été explorées au moyen de la morphométrie géométrique chez quatorze espèces adultes montrant des régimes alimentaires différents. Les résultats révèlent un parallélisme entre la diversité du squelette céphalique et la diversité des régimes alimentaires présent au stade adulte. Dune manière générale, les demoiselles planctonophages possèdent des caractères squelettiques optimisant la prise de nourriture par aspiration (ex : hauts suspensoria et opercules, une large crête supraoccipitale, des mandibules courtes formant une petite bouche). Les espèces brouteuses montrent des pièces squelettiques plus robustes (ex : mandibules hautes et massives, hyomandibulaires larges). Parmi les espèces zooplanctonophages, Chromis viridis et C. acares montrent une morphologie céphalique assez divergente de celle des autres. Leurs caractéristiques squelettiques laissent supposer un mode de prise de nourriture où le poisson capture sa proie en nageant vers elle bouche ouverte (type « ram-suction feeder »). La dentition buccale nest pas toujours corrélée au régime alimentaire. Troisièmement, lontogénie post-colonisation et la variation du niveau de disparité squelettique ont été étudiées et comparées chez huit espèces représentant un échantillon complet de la diversité trophique de la famille. Après la colonisation, les demoiselles subissent des allométries de croissance importantes (40 à 87% des variations de forme). La disparité morphologique est plus grande au stade adulte quau stade de la colonisation pour chaque structure squelettique céphalique. Lensemble des paramètres développementaux étudiés ont subi des changements évolutifs. À la colonisation, les formes larvaires sont déjà spécifiques, probablement à cause de différences dans la durée de vie larvaire pélagique des espèces. Laugmentation de la disparité au cours du développement post-colonisation est essentiellement due à la divergence des patrons allométriques. La longueur des trajectoires ontogénétiques et les vitesses de développement apparaissent comme deux facteurs moins variables. Dune manière générale, peu de liens existent entre les données phylogénétiques ou écologiques (régime, durée de vie larvaire,) et les paramètres développementaux. La diversité du genre Dascyllus illustre des cas de gigantisme. Les méthodes de morphométrie géométrique montrent que les petites espèces et les espèces géantes partagent les mêmes trajectoires ontogénétiques pour le neurocrâne et la mandibule. Au sein de ce groupe, lapparition despèces de grande taille au cours de lévolution résulterait de processus hétérochroniques. La morphologie céphalique larvaire suggère une prise de nourriture de type « ram/suction feeding ». Chez toutes les espèces étudiées, les patrons allométriques révèlent une optimisation du système de prise de nourriture par aspiration au cours du développement. Les demoiselles acquièrent au cours de leur croissance des joues et de opercules proportionnellement plus hauts, une crête supraoccipitale plus grande, des mandibules plus courtes et un processus ascendant du prémaxillaire plus long. Chez les espèces herbivores, dautres changements de forme sont liés à lacquisition de capacités de morsure et de découpe. Par exemple, les mandibules et les suspensoria deviennent plus massifs.

Although differences between selective pressures in hatcheries and streams have been theorized to cause genetic divergence between hatchery and wild salmonids, evidence of this is lacking. This study was initiated to document the presence or absence of genetic change in hatchery and wild stocks by characterizing genetic traits in fish of various life history stages within a single generation. Nine biochemical traits (enzyme loci) and 12 meristic traits were characterized for adult fall chinook and one or more juvenile stages of their progeny of the 1984 brood year. Study groups consisted of hatchery-reared and naturally-reared subunits of populations in two tributaries of the lower Columbia River: Abernathy Creek and the Lewis River. Parents of both groups from Abernathy Creek were primarily of hatchery origin, whereas parents of both groups from the Lewis River were primarily of wild origin. The experimental design thus included reciprocal comparisons of hatchery and wild-reared groups from each of two stocks: one that has been propagated under hatchery conditions for at least five generations and one that has evolved in a stream environment. Both biochemical and meristic traits varied among adult and juvenile stages within hatchery and wild groups. Changes in some of these traits appear to have been caused by natural selection. This was true even for Abernathy hatchery and Lewis wild groups, which have been in the same environment for many generations. The direction and/or degree of change in some biochemical and meristic traits differed between hatchery and wild groups from a given stream, suggesting that selective pressures of the hatchery and wild environments differed in those cases. However, it could not be determined from these data whether the observed divergence of traits reflects general differences in hatchery and stream environments, or if it reflects population-specific responses to site-specific environmental conditions. The extent to which patterns of genetic change within a single generation might vary among year classes or generations is likewise unknown. Evidence of temporal changes in biochemical and meristic traits of hatchery and wild fish within a single generation has important implications regarding the use of those traits to characterize stocks. Assumptions of temporal stability of biochemical or meristic traits within or between year classes should be applied with caution. Sampling strategies of studies involving these characters should account for the possibility of temporal heterogeneity. Finally, these results suggest that workers using allozymes as genetic tags should test the assumption of selective neutrality of the particular allozyme markers being used. / Graduation date: 1991

Recreational drug use peaks in the developmental stage of adolescence in humans. In this dissertation, we used a rodent model of adolescence and behavioral assessments of intravenous (i.v.) cocaine self-administration and reinstatement of cocaine-seeking to explore age differences in these cocaine-related behaviors, and then tested for the influence of environmental enrichment and for correlations between behavior and expression of plasticity genes. Although taking similar amount of cocaine, male rats trained to self-administer cocaine during adolescence (adolescent-onset) showed attenuated cue-induced reinstatement of cocaine seeking compared with adults. This attenuated cue-induced reinstatement did not generalize to a natural reward, sucrose pellets. Then we asked whether the attenuated reinstatement may be due to rapid developmental re-organization of reinforcement circuits (high plasticity) in adolescent-onset groups. To stimulate or inhibit neuroplasticity, subjects experienced environmental enrichment or impoverishment during abstinence. Environmental manipulations had no effect in adolescent-onset groups, whereas the enriched environment attenuated cue-induced reinstatement in adults compared with their impoverished counterparts. Thus, we turned to internal factors that may contribute to age-differences in reinstatement of cocaine seeking. Using in situ hybridization to quantify the mRNA for two neuroplasticity-related genes, activity-regulated cytoskeletal-associated gene (arc) and brain-derived neurotrophic factor (bdnf), we identified that overall, arc expression in the nucleus accumbens (NAc) and bdnf expression in the medial prefrontal cortex (mPFC) was higher in adolescent-onset than in adult groups. Together our data suggest that adolescence in rodents may be a period of relative biological resistance to some long-term drug effects.