No description available.

Gastropods are a highly diverse clade of molluscs that includes limpets, snails and slugs, and the only molluscan lineage with members that have successfully colonized land. Amphibious operculate freshwater gastropods, Ampullariidae, exhibit various morphological and physiological adaptations to their respective habitats, which make them ideal candidates for studying the mechanisms underlying adaptive evolution in gastropods. In the last two decades, there have been interests in the diverse reproductive behaviors of ampullariids: while most genera of apple snails deposit their eggs in a jelly mass underwater, two genera (i.e., Pomacea and Pila) deposit calcareous egg clutches above the waterline. The shift from aquatic to aerial oviposition required the concerted evolution of the adult snail's egg laying behavior as well as the composition of the egg. Today, only limited genomic information is available for this ecologically important family, except in the genus Pomacea, which hinders the investigation of its evolutionary history and mechanism. I have, therefore, developed the publicly accessible transcriptome database, AmpuBase, as molecular resources to support various transcriptomic and proteomic analyses. The database comprise de novo transcriptome assembly of eight species that belong to five representative genera of Ampullariidae. For each species there were 20,730 to 35,828 unigenes with predicted open reading frames, with an N50 ranging from 1,320 to 1,803 bp and 69.7% to 80.2% with functional annotation. Since the ability of laying out-of-water eggs is one of the key steps of terrestrialisation for aquatic snails, I analysed the proteome of perivitelline fluid (PVF) for the eggs of Marisa cornuarietis that were laid underwater. The PVF proteome of P. diffusa also investigated to reveal and compare the biochemical adaptation between P. diffusa clade and P. canaliculata clade. Using LC-MS/MS coupled with transcriptome database, I identified a total of 36 and 32 PVF proteins from M. cornuarietis and P. diffusa, respectively. Comparison of PVF proteomes among the aquatic (M. cornuarietis) and three aerial ovipositing ampullariids (P. diffusa, P. canaliculata and P. maculata) showed that the four species all contain several major perivitellins that are important for the nutrition of the embryos. M. cornuarietis invests heavier in protection against pathogens, whereas the unique presence of calcium binding protein and their high albumen gland expression in three Pomacea, implying the importance of the novel acquisition of this protein for forming the calcareous eggshell of terrestrial eggs. I also found the absence of a neurotoxin (PV2) in M. cornuarietis and P. diffusa PVF, indicating this protein was acquired after the divergence between the ancestors of P. diffusa clade and the P. canaliculata clade, and protects P. canaliculata and P. maculata eggs against terrestrial predators. Evolutionary analyses detected the involvement of gene duplication, positive selection and neofunctionalisation in the formation of several major PVF proteins. With the availability of ampullariid genomes and transcriptomes, I conducted an integrated evolutionary analysis of Pomacea PVF with an aim to understand the molecular adaptations underlying the transition from underwater to terrestrial egg deposition. There were many expanded gene families in the New World ampullariids; some of them may be important for their evolution towards terrestrial egg laying. The PV1 oligomer protein was a novel protein acquired by the common ancestor of New World species to nourishing their terrestrial eggs. Meanwhile, gene duplication followed by neofunctionalisation of MACPF-tachylectin paralogs has contributed to the novel acquisition of the toxic PV2 protein in the P. canaliculata species complex. Overall, using Ampullariidae as an example, my study has demonstrated the power of integrative genomics to address various fundamental questions in evolutionary biology. The findings have enhanced our mechanistic understanding of invasion of terrestrial habitats by aquatic gastropods.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-01-26T15:00:04Z No. of bitstreams: 1 Dissertação - Timoteo Tadashi Watanabe.pdf: 811295 bytes, checksum: 167d496a5bd123f48ac7690e0fa8bb6b (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-01-28T12:42:11Z (GMT) No. of bitstreams: 1 Dissertação - Timoteo Tadashi Watanabe.pdf: 811295 bytes, checksum: 167d496a5bd123f48ac7690e0fa8bb6b (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-01-28T12:42:23Z (GMT) No. of bitstreams: 1 Dissertação - Timoteo Tadashi Watanabe.pdf: 811295 bytes, checksum: 167d496a5bd123f48ac7690e0fa8bb6b (MD5) / Made available in DSpace on 2016-01-28T12:42:23Z (GMT). No. of bitstreams: 1 Dissertação - Timoteo Tadashi Watanabe.pdf: 811295 bytes, checksum: 167d496a5bd123f48ac7690e0fa8bb6b (MD5) Previous issue date: 2014-02-11 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Gastropods from the Ampullariidae family are divided among nine genera being the most famous the Pomacea genera. There is about 20 species of Pomacea that lives in the Amazon ecosystem which has influence of flood pulses of the rivers. So this study evaluated the daily activity and the influence of the flood pulse in the apple snails behavior using Pomacea bridgesii as a model and also evaluated the desiccation resistance of the apple snails comparing the resistance between Pomacea amazonica and P. bridgesii. The gastropods were sampled between May 2012 and June 2013 in the city of Itacoatiara, Amazonas, Brazil. The daily activity, substratum selection and flood pulse simulation were made under natural light and temperature. The behaviors were registered on an ethogram and the daily activity was observed for 48 hours and the flood pulse simulation observations were made during 70 days. In the desiccation resistance experiment, the animals were put in plastics recipients and weighted with 24 hours interval until the death of the animals, after that the animals were dried on a 60ºC kiln to obtain the dry weight. Pomacea bridgesii had more activity during the night where up to 80% of the animals were exploring the tank and during the day up to 80% were immobile. The most used substratum was the pebble. When comparing day with night the part of the usage of pebble during the day shifted to the smooth surface significantly (X²=26.51; DF=3; P<0.05). The behavior of P. bridgesii related to the simulated flood pulse had significant difference between flood peak and dry period but there was no significant difference between the rising water period and the draining period. As for the desiccation resistance, P. amazonica survived a maximum of 314 days and P. bridgesii 157. There was neither difference between the sexes of both species nor difference between species. The size comparison was different for P. amazonica which the small individuals (5--|30 mm) survived less than the medium sized ones (30--|55 mm; H=13.33; DF=2; Z=2.78; P<0.05) and large ones (≥55 mm; H=13.33; DF=2; Z=3.11; P<0.05), and for P. bridgesii the large animals (≥36 mm) survived more time than small individuals (12--|25 mm; H=14.40; DF=2; Z=3.42; P<0.05) and medium ones (25--|36 mm; H=14.40; GL=2; Z=2.90; P<0.05). The species showed similar survival tendency and water loss although the maximum survival time was different. So we can conclude that P. bridgesii displays more activity during the night and had more usage of the pebble substratum during the day, but part of this usage shifted to the smooth surface relating to their nocturnal activity. This species also displayed adaptations to the complex Amazon ecosystem interrupting the activities and closing their operculum to survive the long drought period. And both Pomacea amazonica and P. bridgesii have high desiccation resistance as a part of their adaptations for the ecosystem which allows them to survive the drought period of the Amazon basin and even longer drought periods which may happen. / Os moluscos Ampullariidae estão divididos em nove gêneros sendo Pomacea o mais conhecido mundialmente. Cerca de 20 espécies do gênero Pomacea vivem no ecossistema amazônico sob a influência de um regime de pulsos de inundações. Tendo isso em vista, este estudo avaliou o comportamento diário e a influência do regime de água amazônico no comportamento de Pomacea bridgesii REEVE, 1856 como modelo. Adicionalmente, avaliou-se a resistência à dessecação por Pomacea amazonica REEVE, 1856 e P. bridgesii, para testar a hipótese de que os gastrópodes resistem à seca sazonal que ocorre na região. Os gastrópodes foram coletados entre maio de 2012 e junho de 2013 no Município de Itacoatiara, Amazonas, Brasil. A avaliação da atividade diária, seleção de substrato e simulação do pulso de inundação foram realizadas sob condições de luz e temperatura ambiente. Os comportamentos foram registrados em um etograma elaborado em experimentos preliminares. A atividade diária foi observada por 48 horas e as observações da simulação do pulso de inundação foram feitas em um período de 70 dias. No experimento de resistência à dessecação, os animais foram colocados em recipientes plásticos e pesados a cada 24 horas até a morte do animal; em seguida foram secos em estufa a 60ºC para a obtenção do peso seco. Os animais apresentaram mais atividade durante a noite quando até 80% dos indivíduos estavam explorando o ambiente e até 80% permaneciam imóveis durante o dia. Tanto para o dia como para a noite os gastrópodes utilizaram principalmente o substrato composto por seixo. Comparando a seleção entre o dia e a noite, parte dos animais que utilizavam o seixo durante o dia passou a usar substrato liso significantemente (X²=26,51; GL=3; P<0,05). O comportamento de P. bridgesii em relação à simulação do pulso de inundação mostrou diferença significativa entre a cheia e a seca e não houve diferença significativa entre os períodos da enchente e vazante. Quanto à resistência à dessecação, P. amazonica sobreviveu um tempo máximo de 314 dias e P. bridgesii 157. Não houve diferença da sobrevivência entre os sexos de ambas as espécies e nem quando comparado o tempo entre as espécies. A comparação entre tamanhos foi significativo para P. amazonica em que os indivíduos menores (5--|30 mm) apresentaram uma taxa de sobrevivência menor do que os indivíduos médios (30--|55 mm; H=13,33; GL=2; Z=2,78; P<0,05) e grandes (≥55 mm; H=13,33; GL=2; Z=3,11; P<0,05), e P. bridgesii, em que os indivíduos maiores (≥36 mm) apresentaram uma taxa de sobrevivência maior do que os indivíduos pequenos (12--|25 mm; H=14,40; GL=2; Z=3,42; P<0,05) e médios (25--|36 mm; H=14,40; GL=2; Z=2,90; P<0,05). As espécies apresentaram tendência de sobrevivência e de perda de água semelhantes apesar da diferença de tempo máximo de sobrevivência. Desse modo, pode-se concluir que P. bridgesii possui maior atividade durante a noite, teve maior uso do substrato composto por seixo durante o dia, mas durante a noite parte desse uso passou para o substrato liso relacionado a sua atividade noturna. Também mostrou adaptações ao complexo ecossistema amazônico, interrompendo as atividades e fechando seu opérculo para sobreviver aos longos períodos de seca que ocorrem na região amazônica. E tanto P. amazonica como P. bridgesii possuem elevada resistência à dessecação como parte de sua forma de adaptação suportando todo o período de seca e até mesmo secas de longa duração, evidenciando estarem adaptadas ao ambiente da várzea amazônica.

No description available.