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The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Biologia Marinha e Conservação. A corvinata Cynoscion regalis é um cianídeo com distribuição nativa na costa leste norte-americana e Canadá. No entanto, foram registados alguns avistamentos na Europa desde 2009, nomeadamente em águas portuguesas. Devido ao potencial invasivo desta espécie, este estudo visa a primeira caracterização genética da corvinata em Portugal. A análise do fragmento D-loop de C. regalis revelou que as localizações portuguesas têm valores mais baixos de diversidade genética comparativamente à Flórida. A rede de haplótipos construída revelou o baixo polimorfismo desta espécie, não havendo partilha de haplótipos entre os dois lados do Atlântico. A AMOVA realizada mostrou estrutura populacional para a espécie, enquanto a análise hierárquica revelou ausência de estrutura genética entre populações em águas portuguesas. A análise de conteúdos estomacais revelou que a maioria dos indivíduos ingeridos eram coespecíficos. A ingestão de espécies como Atherina presbyter, Spondyliosoma cantharus e Engraulis encrasicolus confirma a ocupação do estuário por parte da corvinata, podendo potenciar os efeitos negativos na sua distribuição não nativa. Weakfish Cynoscion regalis is a native sciaenid from the east coast of north-America and Canada. However, this species has been recorded in Europe since 2009, namely in Portuguese waters. Due to its invasive potential, this study aims to be the first genetic characterization of weakfish in Portugal. The analysis of the D-loop fragment of C. regalis revealed that Portuguese populations present lower values of genetic diversity compared to Florida. The haplotype network revealed the low polymorphic nature of this species, with no haplotypes being shared between Atlantic coasts. The AMOVA analysis revealed population structure for the species, while the hierarchical analysis yielded no genetic structure among populations within Portuguese waters. Stomach content analysis showed that the majority of the ingested prey were conspecifics. The ingestion of species such as Atherina presbyter, Spondyliosoma cantharus and Engraulis encrasicolus confirms the weakfish occupation of the estuary, potentially enhancing the negative effects at its non-native range.

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Biologia Marinha e Conservação. Venomous marine vertebrates remain poorly studied compared to their terrestrial counterparts. Venoms are valuable resources for the discovery of new compounds with biotechnological potential, namely, in health sciences. However, to discover new proteins with pharmaceutical interest, it is necessary to acquire basic knowledge on venomous species and their venom “cocktails”. Phylogeny can be used as a roadmap to guide research in this field, by allowing to know the relationships between species and prospect about the existence of similar proteins in closely related species not yet studied. Scorpaena are known marine venomous fish, with species distributed throughout all the oceanic basins. In some NE Atlantic and Mediterranean Sea countries, they are known to be part of the range of species caught by artisanal fishing, and for causing episodes of envenomation. In this work, the phylogeny of 8 of the 9 Scorpaena species from the NE Atlantic and Mediterranean Sea was studied. This was the first phylogeny to encompass such a wide number of species of this genus. In parallel, protein profiles from five Scorpaena species were investigated, concluding that their venom profiles seem to differ in protein composition, even comparing sister species. This result supports the hypothesis of fish venoms suffering natural selection and allows to recognize the utility of phylogeny in guiding biotechnological studies with venoms from marine organisms. Os vertebrados marinhos venenosos permanecem relativamente pouco estudados quando os comparamos com os seus homólogos terrestres. Os venenos são um recurso valioso para a pesquisa de novos compostos com potencial biotecnológico, nomeadamente na área da saúde. Contudo, para conhecer novas proteínas de interesse farmacêutico, é necessário conhecer as espécies e os seus “cocktails” venenosos. A filogenia pode ser uma ferramenta para conduzir a investigação nesta área, ao perspetivar a existência de uma molécula bioativa no veneno de espécies relacionadas que ainda não houve oportunidade de estudar. O género Scorpaena inclui peixes marinhos venenosos que se distribuem por todas as bacias oceânicas. Em alguns países do Nordeste do Oceano Atlântico e do Mar Mediterrâneo, são conhecidas por fazerem parte do leque de espécies capturadas na pesca artesanal, e pelos episódios de envenenamento que causam. Neste trabalho foi estudada a filogenia de 8 das 9 espécies de Scorpaena do Nordeste do Oceano Atlântico e do Mar Mediterrâneo, sendo esta a primeira filogenia a englobar um número tão abrangente de espécies deste género. Paralelamente, os perfis proteicos dos venenos de cinco destas espécies foram investigados, concluindo-se que diferem entre si inclusive quando são comparados perfis de venenos de espécies irmãs. Esta diversidade pode ser suportada por hipóteses alternativas, nomeadamente a de que os venenos estão sob ação de seleção natural ou estes venenos representam traços antigos de divergência rápida. Os resultados desvendam informação acerca da evolução destas espécies e dos seus venenos, permitindo assim reconhecer a utilidade da filogenia como um mapa a utilizar em estudos biotecnológicos no futuro.

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Biologia Marinha e Conservação. Submitted by Paulo Pinhão Nunes (pnunes@ispa.pt) on 2019-12-06T10:46:36Z No. of bitstreams: 1 26031.pdf: 3005177 bytes, checksum: cc6821ce4c83363035cb5d74a4fbedb1 (MD5) Made available in DSpace on 2019-12-06T10:46:37Z (GMT). No. of bitstreams: 1 26031.pdf: 3005177 bytes, checksum: cc6821ce4c83363035cb5d74a4fbedb1 (MD5) Previous issue date: 2019-11-11

International audience; Lipopolysaccharides (LPS) are potent activator of the innate immune response through the binding to the myeloid differentiation protein-2 (MD-2)/toll-like receptor 4 (TLR4) receptor complexes. Although a variety of LPSs have been characterized so far, a detailed molecular description of the structure-activity relationship of the lipid A part has yet to be clarified. Photosynthetic Bradyrhizobium strains, symbiont of Aeschynomene legumes, express distinctive LPSs bearing very long-chain fatty acids with a hopanoid moiety covalently linked to the lipid A region. Here, we investigated the immunological properties of LPSs isolated from Bradyrhizobium strains on both murine and human immune systems. We found that they exhibit a weak agonistic activity and, more interestingly, a potent inhibitory effect on MD-2/TLR4 activation exerted by toxic enterobacterial LPSs. By applying computational modeling techniques, we also furnished a plausible explanation for the Bradyrhizobium LPS inhibitory activity at atomic level, revealing that its uncommon lipid A chemical features could impair the proper formation of the receptorial complex, and/or has a destabilizing effect on the pre-assembled complex itself.