Elevated atmospheric CO2 has been implicated as a driver of increased liana abundance worldwide. Known as disturbance creators and beneficiaries, lianas possess the potential to significantly influence forest ecosystems. I investigated the early-invasion dynamics of Euonymus fortunei (wintercreeper), an evergreen liana that is invading forests in eastern North America, disrupting native plant communities and ecosystem functions. Wintercreeper is widely cultivated as an ornamental groundcover, frequently invading natural areas via asexual stem growth. Invasion of remote natural areas is dependent upon seed transport and may occur less frequently. I examined the mechanisms of seed dormancy by conducting a ‘move-along’ experiment using fresh and after-ripened seeds. Additionally, I sought to characterize the nature of seed dispersal by birds by deploying seed traps within an invaded forest in central Kentucky. Wintercreeper seeds displayed conditional nondeep physiological dormancy. Although germination occurs at high velocity following cold stratification, a cold period was only facultative to break dormancy. While fresh seeds had greater germination rates (98.6%) compared to after-ripened seeds (85.7%), after-ripened seeds experienced earlier germination (41 days across all treatments). My findings also indicate that bird-mediated seed dispersal occurs throughout the winter from seeds that after-ripen on maternal liana phanerophytes. Overall, these data suggest wintercreeper seeds are capable of dispersing and recruiting in areas with mild to non-existent winters. The invasion of natural areas by exotic invaders is regulated by biotic and abiotic processes, which influence the invader’s success or failure. I studied the vegetation and soil effects of paired invaded (INV), uninvaded (NAT), and ‘restored’ (RES) sites on the germination and survival of wintercreeper seeds and seedlings. The effect of aril (with vs. without) was also tested, both in the field and in vitro. In the field, total germination and first year survival were 55.6% and 24.2%, respectively, across treatments. Total germination was unaffected by treatments, yet vegetation (P = 0.0016) and aril (P = 0.001) treatments significantly influenced germination rates over time, including delayed germination of seeds with arils. The proportion of germinated seedlings that survived was significantly different based on vegetation (P = 0.054) and aril (P = 0.071) treatments after the first winter of growth, but not prior to the first winter. The proportion of seedling survival was significantly lower among seeds dispersed with an aril and seeds sown within INV treatments; there were no interactive effects. Finally, I examined how seedling density and growth habit (horizontal vs. vertical) influenced plant survival, growth, and allometry. I also tested extractable soil C, N, P, K, Ca, and Mg prior to planting and after 17 months of soil conditioning. I found evidence that increased planting density negatively influenced growth among individual plants (lower survival, basal diameter, shoot mass, root mass). At the plot level, high-density plantings yielded greater stem length, and shoot, root, and combined biomass, indicating positive frequency dependence for this species. Soil analyses indicated C, N, P, Ca, and Mg significantly increased (P < 0.05) over the course of the experiment. I conclude that in wintercreeper, prominent asexual propagation leads to aggregate populations whose total contributions to above- and belowground biomass are positively correlated with density, even though individual plant fitness is not. Altogether, this work provides insight into how wintercreeper invasions occur at broad and fine scales. This information will provide a foundation for future wintercreeper studies and aid land managers in their prevention and control strategies.

Lors de l’invasion tumorale, les cellules épithéliales tumorales acquièrent des propriétésmigratoires et invasives impliquant des modifications phénotypiques importantes. Parmi ceschangements, on observe notamment une réorganisation ou une perte des complexes d’adhérenceintercellulaire et une acquisition de la capacité à dégrader la matrice extracellulaire à travers uneaugmentation d’expression des métalloprotéinases matricielles (MMPs). Dans cette étude, nous noussommes plus particulièrement intéressés aux jonctions serrées qui sont constituées de protéinestransmembranaires (occludine, claudines) liées au cytosquelette d’actine par des protéinescytoplasmiques sous-membranaires incluant les Zonula Occludens (ZO-1, -2 et -3). Parmi cesmolécules, nous avons évalué le rôle potentiel de ZO-2 dans l’acquisition de propriétés invasives parles cellules tumorales. In vivo, nous avons montré une diminution d’expression des ZOs dans lescancers broncho-pulmonaires avec une localisation cytoplasmique préférentielle. De plus, in vitro, lalocalisation des ZOs varie en fonction du potentiel invasif des cellules tumorales et leur réorganisationest corrélée à la migration cellulaire. Nous démontrons également que l’inhibition de ZO-2 augmenteles capacités invasives de cellules tumorales invasives et s’accompagne d’une augmentationd’expression des MMP-2 et -14 et du facteur de transcription ZEB-2. Ces résultats suggèrent que ZO-2, composant structural des complexes d’adhérence intercellulaire dans les cellules différenciées,pourrait jouer un rôle clé dans le processus d’invasion tumorale. Sa capacité à transiter de lamembrane au cytoplasme et/ou au noyau lui permettrait d’agir comme une molécule de signalisationen régulant la transcription de gènes. Les données obtenues démontrent un rôle anti-invasif de ZO-2. / During tumor invasion, tumor epithelial cells acquire migratory and invasive propertiesinvolving important phenotypic alterations. Among these changes, one can observe a reorganization ora loss of cell-cell adhesion complexes such as tight junctions and an increased ability to degradeextracellular matrix through an enhanced expression of matrix metalloproteinases (MMPs). Tightjunctions are composed of transmembrane proteins (occludin, claudins) linked to the actincytoskeleton through cytoplasmic adaptor molecules including those of the zonula occludens family(ZO-1, -2, -3). Among these molecules, we evaluated the potential role of ZO-2 in the acquisition ofinvasive properties by tumor cells. In vivo, we showed a decrease of ZOs expression in bronchopulmonarycancers with a preferential localization in the cytoplasm. In addition, in vitro, thelocalization of ZOs varies according to invasive properties of tumor cells and their reorganization iscorrelated with cell migration. We also demonstrate that ZO-2 inhibition increases invasive capacitiesof invasive tumor cells. This was associated with an increase of MMPs (MMP-2 and -14) and thetranscription factor ZEB-2 expression. These results suggest that ZO-2, known as a structuralcomponent of cell-cell adhesion complexes in differentiated epithelial cells, could play a key role intumor invasion through its ability to shuttle from the membrane to the cytosol or nucleus, and act assignaling molecule regulating gene transcription. This study shows an anti-invasive role of ZO-2.

Biological invasions are one of the most important threats to global biodiversity and they were also found to negatively affect some bird species. Despite relatively large number of scientific studies dealing with the impacts of invasive plants on bird communities, their results are inconsistent, especially it is not clear how birds respond to increasing levels of expansion of invasive species in native species stands. Moreover, bird responses to plant invasions seem to depend on the ecological characteristics of individual bird species. This study contributes to elucidation of this problem; I investigated the impacts of black locust (Robinia pseudoacacia) invasion on bird communities in three types of forest stands with different levels of invasion: in stands containing solely the native oak (Quercus spp.), in partially invaded stands with different proportions of black locust and oak (mixed stands) and in pure black locust stands. Previous studies that examined birds in pure oak and pure black locust stands have found that they differ markedly in vegetation structure, but not in the total number of bird species. However, habitat specialists were associated with the oak stands, while generalists with the black locust stands. Therefore, I predicted that (1) the total species richness will be...

NG2 is a transmembrane glycoprotein mainly expressed in developing tissue, and often re-expressed in tumor cells. NG2 glycoprotein is an important regulator of cell migration and adhesion. Increased expression of NG2 enhances the metastatic potential of cancer cells. However, the molecular mechanisms of these processes are still not fully understood. An increasing number of evidences, in recent years, have shown that NG2 can be responsible for Rho/ROCK activation, which is essential for effective amoeboid invasiveness. In this thesis, we analysed the role of NG2 glycoprotein, especially the role of its PDZ- binding motif on amoeboid phenotype induction, and activation of Rho/ROCK signaling. Our results demonstrate the importance of the NG2 PDZ-binding motif on mesenchymal- amoeboid transition of cells in a 3D environment. Surprisingly, they show that the expression of both the NG2 cytoplasmatic domain and the truncated version, lacking the PDZ-binding motif, do not change the amount of Rho-GTP or the activation of the Rho/ROCK signaling pathway in 2D.

Os gliomas apresentam comportamento amplamente infiltrativo e a invasão para o tecido cerebral sadio adjacente ao tumor o tornam um grande desafio para intervenções clínicas agressivas. Estudos recentes dos mecanismos de invasão de gliomas sugerem que as metaloproteinases (MMPs) desempenham papel crítico neste processo. As MMPs são super-expressas em quase todos os tumores humanos e vastos dados pré-clínicos as apontam como contribuintes do desenvolvimento maligno; portanto, a inibição de atividade de MMPs poderia ser adotada como uma estratégia de terapêutica anti-câncer. A atividade inibitória de MMP-2 e MMP-9 do extrato liofilizado da raiz de P. umbellata foi avaliada em estudos prévios de nosso laboratório por Ropke e colaboradores. Assim, esta dissertação teve como objetivo, primeiramente, explorar a citotoxicidade do extrato de P. umbellata e posteriormente, a avaliar o efeito do 4-neroridilcatecol (o princípio ativo isolado do extrato) quanto à citotoxicidade e potencial de inibição de MMPs durante o processo de invasão de duas linhagens de glioma humano, caracterizadas pelos diferentes níveis de invasividade. Os resultados revelam os índices de citotoxicidade do extrato bruto da raiz de P. umbellata e do composto 4-NC presente nesse extrato. Ensaios de invasão tumoral in vitro em concentrações não citotóxicas mostraram que há forte inibição desse processo pelo composto. Interessantemente, o 4-NC não alterou significativamente a atividade e expressões gênicas e protéicas de MMPs envolvidas na invasão deste tipo de tumor, nem de seus reguladores. O ensaio de fragmentação do DNA nos indica que a morte das células é, em parte, devido à apoptose, além da participação do processo autofágico. Ensaios analisando a expressão de proteínas e genes envolvidos na via de autofagia mostraram que há indução deste processo pelo composto estudado. Quando este processo é inibido farmacologicamente há incremento na morte celular causada pelo 4-NC. Considerando que em câncer, a autofagia é um processo essencial na modulação da resistência a quimioterápicos, descrevemos aqui, que 4-NC, a exemplo de seu poder citotóxico em melanomas, atua no processo invasivo de gliomas e induz morte celular além de desencadear o processo autofágico. / Gliomas present extensive invasive behavior and the invasion to healthy adjacent neural tissue makes this type of tumor a great challenge for aggressive clinical intervention. Recent studies concerning glioma invasion mechanisms suggest that metalloproteinases (MMPs) have a critical role in this process. MMPs are overexpressed in almost all types of human tumors and many pre-clinical data point to them as functional enhancers to malignant development; then, the inhibition of MMP activity could be adopted as an anti-cancer therapeutic strategy. P. umbellate root extract inhibitory activity over MMPs-2 and 9 was previously evaluated in studies from our group by Ropke et al. Thus, this dissertation has as an objective to evaluate the cytotoxic effect of 4-nerolidylcatechol (a compound purified from the P. umbellate extract), and its potential for MMP inhibition during the invasive process of two human glioma cell lines, characterized for their different invasive levels. Our results show the cytotoxic levels of the crude extract from the root of P. umbellate and from the 4-NC isolated from the extract. In vitro tumor invasion assay in non-cytotoxic drug concentrations indicate a strong inhibition of this process by the compound. Interestingly, 4-NC did not significantly alter enzyme activity, genetic or proteic expression of the MMPs involved in glioma invasion, or its regulators. The DNA fragmentation assay shows that cells die, in part, due to apoptosis, but autophagy pathway is also involved in cell death. Assays showing expression of proteins and genes involved in the autophagy pathway showed an increase of this process by the compound studied. Pharmacological inhibition of this process leads to an increase in cell death caused by 4-NC. Considering that in cancer, autophagy plays an essential role in the modulation of chemoresistance, we describe here that 4-NC, as described previously for melanomas, acts on glioma invasive process, induces cell death and is capable of up-regulating autophagic process.

OBJETIVOS: Estudar variáveis anatomopatológicas relacionadas à progressão tumoral em carcinomas uroteliais primários de bexiga e sua associação com a imunoexpressão de metaloproteinases de matriz (MMPs) - 2, -9 e -14 no epitélio e no estroma dos tumores primários e nas metástases linfonodais. MÉTODOS: Sessenta e um casos de carcinomas uroteliais musculoinvasivos ou localmente avançados primários da bexiga operados no Hospital das Clínicas da Faculdade de Medicina da USP e no Instituto do Câncer do Estado de São Paulo, sendo 34 casos com metástase para linfonodo regional, foram caracterizados quanto ao gênero, idade, tamanho, focalidade, grau histológico, tipo/configuração neoplásica, tipo papilífero da neoplasia, padrão arquitetural de invasão tumoral, grau de atipia nuclear, componente sarcomatoide, diferenciações escamosa e glandular, variante histológica, invasões linfovascular e perineural, carcinoma in situ, estádio do tumor primário, metástase para linfonodo regional, tamanho da metástase e extensão extranodal. Amostras teciduais de 1,0 mm foram dispostas em micromatrizes teciduais (TMA) para pesquisa imuno-histoquímica (IH) das enzimas MMP-2, MMP-9 e MMP-14. A expressão IH das MMPs foi graduada em uma escala semiquantitativa de 0 (ausência de expressão) até 20 (maior expressão). As associações entre a imunoexpressão das MMPs de forma global, no epitélio e estroma do tumor primário e na metástase linfonodal com as variáveis anatomopatológicas foram avaliadas através do teste do qui-quadrado de Pearson, sendo consideradas significativas ao nível de p<0,05. RESULTADOS: Trinta e seis, 57 e 60 casos do tumor primário foram positivos para MMP-2, MMP-9 e MMP-14, respectivamente. Nas metástases linfonodais, 20, 27 e 26 casos foram positivos para MMP-2, MMP-9 e MMP-14, respectivamente. A imunoexpressão global de MMP-2 no tumor primário mostrou-se associada com o padrão arquitetural de invasão (p=0,022) e sua expressão no estroma com o grau de atipia nuclear (p=0,032) e a porcentagem de componente sarcomatoide (p=0,003). A imunoexpressão global de MMP-9 no tumor primário mostrou-se associada com diferenciação escamosa (p=0,033). O padrão arquitetural de invasão relacionou-se com a expressão de MMP-9 no epitélio (p=0,043) e no estroma (p=0,044). A expressão de MMP-9 no estroma mostrou-se associada com o grau de atipia nuclear (p=0,031), componente sarcomatoide (p=0,036) e com a porcentagem desse componente no tumor primário (p=0,013). O estádio tumoral agrupado pT2+pT3 vs pT4 demonstrou associação com a MMP-9 expressa no epitélio (p=0,049). Para a MMP-14, o padrão arquitetural de invasão demonstrou associação significativa com a imunoexpressão global (p=0,022) e no epitélio tumoral (p=0,045). A porcentagem de componente sarcomatoide relacionou-se ainda com a expressão estromal de MMP-14 (p<0,001). Considerando a imunoexpressão de MMPs apenas na metástase linfonodal, houve associação significativa da MMP-9 com o tipo de variante histológica do tumor (p=0,021) e da expressão de MMP-14 com a porcentagem de componente sarcomatoide no tumor primário (p=0,017). CONCLUSÃO: O estudo da imunoexpressão de MMP-2, MMP-9 e MMP-14 em amostras organizadas em TMA, tanto no epitélio como no estroma dos carcinomas uroteliais de bexiga e nas metástases de linfonodos regionais, demonstrou associações estatísticas com características anatomopatológicas reconhecidas como de prognóstico ruim para essas neoplasias, indicando a ação dessas enzimas na transição epitélio-mesênquima e nas etapas de progressão e metástase dos carcinomas uroteliais / OBJECTIVES: To study morphological features related to tumor progression in urothelial carcinoma of the urinary bladder and its association with immunohistochemical (IHC) expression of matrix metalloproteinases (MMPs) -2, -9 and -14 in epithelial and stromal cells of primary tumor and regional lymph node metastases. METHODS: Sixty-one cases of muscle-invasive or locally advanced urothelial carcinomas of the bladder operated on Clinic\'s Hospital of Faculty Medicine Sao Paulo University and the Cancer Institute of the State of Sao Paulo, with 34 cases showing regional lymph nodes metastases, were characterized regarding gender, age, tumor size, multifocality, histological grade, neoplastic type/configuration, papillary type, architectural pattern of invasive tumor, nuclear atypia, sarcomatoid component, squamous and glandular diffentiation, histological variants, lymphovascular and perineural invasion, carcinoma in situ, tumor stage, metastases to regional lymph nodes, metastases size and extranodal extension. Tissue samples of 1.0 mm were arranged in tissue microarrays blocks (TMA) for IHC detection of MMP-2, MMP-9 and MMP-14. The grading of expression of MMPs was determined to a semiquantitative scale from 0 (absence) to 20 (higher expression). The associations between the IHC global expression of MMPs, in epithelium and in stromal cells of the primary tumor and in the lymph node metastases with the morphological features were obtained through Pearson\'s chi-square (significant at p<0.05). RESULTS: Thirty-six, 57 and 60 cases of primary tumor were positive for MMP-2, MMP-9 and MMP-14 respectively. In the lymph nodes metastases, 20, 27 and 26 cases were positive for MMP-2, MMP-9 and MMP-14 respectively. The global IHC expression of MMP-2 in primary tumor has been associated with the architectural pattern of invasion (p=0.022). The expression in stromal cells were correlated with the degree of nuclear atypia (p=0.032) and the percentage of sarcomatoid component (p=0.003). The IHC expression of MMP-9 in primary tumor has been associated with squamous differentiation (p=0.033). The architectural pattern of invasion was related to the expression of MMP-9 in epithelium (p=0.043) and in the stroma (p=0.044). Expression of MMP-9 in the stroma was associated with the degree of nuclear atypia (p=0.031), sarcomatoid component (p=0.036) and the percentage of this component in primary tumor (p=0.013). The grouped tumoral stage pT2+pT3 vs pT4 showed association with MMP-9 expressed in epithelium (p=0.049). For MMP-14, the architectural pattern of invasion showed significant association with global IHC expression (p=0.022) and tumor epithelium (p=0.045). The percentage of sarcomatoid component related to the estromal expression of MMP-14 (p<0.001). Considering the IHC expression of MMPs in lymph nodes metastases, there was a significant association between MMP-9 with the type of histological variants (p=0.021) and the expression of MMP-14 with the percentage of sarcomatoid component in primary tumor (p=0.017). CONCLUSION: The study of IHC expression of MMP-2, MMP-9 and MMP-14 in bladder carcinoma samples arranged in TMA, both in epithelium and in stromal cells and regional lymph nodes metastases, demonstrated significant association with morphological features recognized as prognostically important for these tumors. These findings herald the importance of action of these enzymes in epithelialmesenchymal transition, providing basis for the understanding of tumoral progression and metastases in urothelial carcinoma

Invasões biológicas tem um papel cada vez mais importante nas políticas ambientais, visto que espécies invasoras desempenham uma crescente influência sobre novos ambientes onde são introduzidas, podendo gerar grandes impactos naturais e financeiros. Estudos na área da biologia da invasão se fazem extremamente necessários para remediar e evitar novas introduções. Dentre as metodologias aplicadas ao estudo das invasões biológicas, a genética de populações apresenta diversas ferramentas uteis para responder perguntas relevantes nos esforços de controle de espécies invasoras. No presente trabalho usamos recursos moleculares aplicados à genética de populações da rã-touro (Lithobates catesbeianus), o anfíbio invasor mais disseminado no planeta. Através deste estudo foi possível compreender mais sobre a estrutura genética das populações invasoras do Brasil e do mundo, além de seu histórico de invasão e sua população nativa de origem. Entender e contextualizar as características e motivos que levam ao sucesso de uma invasão biológica é importante para esforços de combate a pragas e para evitar que outros invasores se fixem em novos ambientes. Este trabalho levantou novos conhecimentos que podem e devem ser usados em políticas de combates à invasão da rã-touro / Biological invasions play an increasingly important role in environmental policies as invasive species represent a growing impact in new environments where they are introduced, potentially causing large natural and financial problems. Studies in the field of invasion biology are extremely necessary to remedy and prevent new introductions. Among the methodologies applied to the study of biological invasions, population genetics presents several useful tools to answer relevant questions in efforts to control invasive species. In the present work we used molecular resources applied to the genetics of populations of the American Bullfrog (Lithobates catesbeianus), the most widespread invasive amphibian on the planet. Through this study it was possible to understand more about the genetic structure of the invasive populations in Brazil and in the world, and its history of invasion and its native population of origin. Understanding and contextualizing the characteristics and motives that lead to the success of a biological invasion is important for pest control efforts and to prevent other invaders from focusing on new environments. This work has raised new knowledge that can and should be used in policies to combat Bullfrog invasion

Invasões biológicas representam hoje a segunda maior ameaça à biodiversidade, e o homem desempenha papel fundamental na introdução de espécies exóticas potencialmente invasoras. O cachorro (Canis lupus familiaris) é uma dessas espécies. Presente em todos os continentes, é o carnívoro mais abundante do mundo, e pode causar impactos à fauna nativa através de efeitos letais e não letais da predação, competição, hibridização e transmissão de doenças, além de ser potencialmente importante na epidemiologia de zoonoses. Em áreas rurais, que concentram grande parte dos remanescentes de vegetação nativa no mundo, os cachorros são frequentemente criados soltos e circulam livremente, intensificando a chance de contato com a fauna nativa. Nesse trabalho, avaliamos a importância relativa de fatores associados a atributos individuais (sexo, idade, condição de saúde, comportamento exploratório, tamanho e raça), formas de manejo (incentivo do dono à movimentação, motivo para a criação, confinamento e frequência de alimentação) e contexto ambiental (proximidade à mata nativa) para determinar a chance de cachorros visitarem remanescentes florestais em paisagens fragmentadas de Mata Atlântica. Selecionamos oito paisagens de 2830 ha cada, nas quais visitamos todas as construções em áreas rurais a fim de entrevistar, através da aplicação de questionário, os responsáveis pela criação de cachorros e fotografar os cachorros. Utilizamos a imputação múltipla para estimar os dados faltantes (comuns em dados obtidos via questionários), gerando 10 conjuntos de dados imputados que foram analisados separadamente. Por meio de seleções de modelos através do Critério de Informação de Akaike, comparamos modelos candidatos com até cinco variáveis independentes para determinar a chance de cachorros visitarem remanescentes florestais. Nossos resultados nos permitem afirmar que quatro fatores - dois associados a atributos individuais e dois associados a formas de manejo - atuam em conjunto para determinar a chance de cachorros visitarem remanescentes florestais em paisagens rurais da Mata Atlântica. Cachorros maiores, mais exploradores, que recebem mais incentivo a se movimentar e que passam menos tempo confinados têm maior chance de visitar remanescentes florestais. A maior importância de atributos individuais e da forma de manejo está de acordo com a grande variação fenotípica existente entre cachorros e a variedade de modos como são manejados. Entre os atributos individuais, tanto características físicas como comportamentais são importantes, enquanto os aspectos chave da forma de manejo são aqueles mais diretamente relacionados à movimentação dos cachorros. Independentemente do tempo de confinamento, o incentivo do dono à movimentação do cachorro, em particular o estímulo para que o cachorro o acompanhe em visitas a remanescentes florestais, é fundamental. O contexto ambiental, em especial a proximidade do domicílio a áreas de mata nativa, por sua vez, é irrelevante dada a alta mobilidade dos cachorros. Nossos dados sugerem que a densidade de cachorros em paisagens rurais de Mata Atlântica é uma ordem de magnitude mais alta do que a de carnívoros de médio porte silvestres relativamente comuns, que muitos cachorros já tiveram contato direto com espécies silvestres, e que a vacinação e outras medidas profiláticas são relativamente incomuns. Todos esses dados indicam o potencial de efeitos negativos, tanto para a fauna silvestre como para o homem. Programas de redução destes impactos devem incluir tanto aspectos veterinários, como a expansão de campanhas públicas de profilaxia para além da vacinação antirrábica, quanto aspectos sociais, como a divulgação e conscientização dos potenciais problemas ocasionados pela entrada de cachorros em áreas de vegetação nativa, visando mudanças nas crenças, atitudes e comportamento da população humana / Biological invasions are today the second greatest threat to biodiversity, and humans play a significant role in the introduction of potentially invasive exotic species. The dog (Canis lupus familiaris) is one of such species. Distributed across all continents, the dog is the most abundant carnivore in the planet, and can impact wildlife through lethal and non-lethal effects of predation, competition, hybridization and disease transmission, besides being potentially important in the epidemiology of zoonoses. In rural areas where most remnants of native vegetation around the world are concentrated, most dogs are free-ranging, enhancing the chance of interactions with wildlife. Here, we evaluated the relative importance of factors associated with individual traits (sex, age, health condition, exploratory behaviour, size and breed), management (owner\'s incentive to movement, motive for raising, confinement and feeding frequency), and environmental context (proximity to native forest) to determine the chance of dogs visiting forest remnants in Atlantic Forest fragmented landscapes. We selected eight landscapes of 2830 ha each, where we visited all constructions in rural areas in order to interview dog owners by applying a questionnaire and to photograph dogs. We used multiple imputation to estimate missing data (common in data obtained through questionnaires), obtaining 10 imputed datasets that were analyzed separately. We compared candidate models with up to five independent variables to determine the chance of dogs visiting forest remnants through the Akaike Information Criterion. Our results indicate that four factors - two associated with individual traits and two associated with management - work together to determine the chance of dogs visiting forest remnants in Atlantic Forest rural landscapes. Larger dogs, and those that exhibit exploratory behaviour, are more stimulated to move or confined for shorter periods have greater chance of visiting forest remnants. The greater importance of factors associated with individual traits and management is in accordance with the ample phenotypic variation among dogs and the variety of ways they can be managed. Among individual traits, both morphological and behaviour characteristics are important, whereas the key aspects of management are those directly related to dog movement. Irrespective of the time confined, the owner\'s incentive to movement, in particular taking the dog to the forest, is a crucial aspect. In contrast, the environmental context, especially the proximity of the household to native forest, is irrelevant given the vagility of dogs. Our results suggest that the density of dogs across rural landscapes in the Atlantic forest is at least one order of magnitude higher than the density of relatively common medium-sized native carnivores, that several dogs have already had direct contact with wild species, and that vaccination and other prophylactic measures are relatively uncommon. All of these highlight the potential for negative effects on both wildlife and human population. Plans to reduce these effects should include not only veterinarian aspects, such as the expansion of public prophylactic campaigns beyond rabies vaccination, but also social aspects, such as the dissemination of information on the problems caused by dogs visiting native vegetation, aiming at changing people\'s beliefs, attitudes and behaviour

Invasões biológicas representam atualmente a segunda maior ameaça à biodiversidade e dois fatores são considerados os mais importantes para o sucesso de invasões: pressão de propágulos e distúrbios. Um tipo de distúrbio antrópico que pode promover invasões, por mudar a quantidade de habitats alterados e a extensão de bordas entre eles e habitats nativos, é a perda de habitat. Apesar da reconhecida importância da pressão de propágulos e dos distúrbios, poucos estudos os investigaram simultaneamente e, os que o fizeram, apresentam limitações, como escalas espaciais pequenas e correlações entre os determinantes, dificultando a compreensão da importância relativa e interações entre eles. Cachorros são os carnívoros mais abundantes no mundo. Em áreas rurais, a maioria mantém comportamento de animal de vida de livre, interagindo com e afetando espécies nativas através de predação, transmissão de doenças e competição. Usando um banco de dados obtido através de armadilhas fotográficas e censo da população de cachorros em uma região de Mata Atlântica de 300,000 ha, avaliamos a importância relativa e interações entre pressão de propágulos e distúrbios para a invasão por cachorros. Selecionamos 12 paisagens de 2830 ha cada, variando de 10 a 50% de floresta nativa remanescente. Em cada uma, alocamos através de amostragem aleatória estratificada 8 pontos de amostragem em florestas nativas, onde uma armadilha fotográfica foi instalada por &sim;42 dias consecutivos. Todos os domicílios em cada paisagem foram visitados para a contagem do número de cachorros. A pressão de propágulos foi quantificada como a densidade de cachorros criados e a média e mediana das distâncias entre os locais de criação e a floresta nativa mais próxima; e distúrbios, como a proporção da paisagem ocupada por floresta nativa e total (nativa e exótica) e a extensão de bordas entre florestas nativas e áreas abertas. Através da identificação de cachorros nas fotos e considerando cada paisagem como uma unidade amostral, nós comparamos por AICc modelos de abundância (N-mixture) para estimar a abundância de cachorros em florestas nativas, considerando a detecção imperfeita. O único modelo selecionado indica que a abundância de cachorros em florestas nativas é maior onde a densidade de cachorros é mais alta e a cobertura florestal total é menor (&omega;i=0.82). A densidade de cachorros criados foi mais importante que a distribuição espacial dos indivíduos, e a cobertura floresta total mais importante que a extensão de bordas, para a abundância de cachorros invasores. A abundância estimada de cachorros variou de 12 a 79 (30.9 ± 19.5), e a proporção de cachorros criados que invadem florestas de 6 a 21% (12 ± 6%), entre as paisagens. Nossos resultados indicam que a perda de habitat é tão importante quanto a pressão de propágulos para a invasão de florestas nativas por cachorros, mas seus efeitos são aditivos em vez de sinérgicos. Dado que cachorros frequentemente realizam movimentos longos em áreas abertas, nós levantamos a hipótese de que a capacidade de deslocamento é a causa do efeito desprezível da distribuição espacial dos indivíduos criados sobre a invasão, e que florestas representam barreiras a estes movimentos, tornando o efeito da cobertura florestal mais importante do que o efeito da extensão de bordas (mais relacionada a extensão de acesso a floresta). Além disso, o número e proporção de cachorros invasores são expressivos, colocando o cachorro na posição de carnívoro mais abundante em remanescentes florestais. Junto com os conhecidos impactos severos de cachorros sobre espécies nativas, estes números sugerem a urgência de planos de ação para controlar a invasão por cachorros. Além dos métodos tradicionais de controle populacional, o contexto da paisagem deve ser levado em conta nestes planos. Paisagens muito desmatadas devem ser priorizadas, e manter e restaurar florestas também devem ser valorizados pelos efeitos negativos sobre invasões biológicas. Por fim, dada a associação da invasão por cachorros com a perda de habitat e com a densidade de cachorros e da população humana, sugerimos que pelo menos parte dos efeitos negativos sobre mamíferos nativos usualmente atribuídos ao desmatamento e a caça podem ser causados pela invasão por cachorros / Biological invasions are currently the second main threat to biodiversity and two drivers are considered as the most important for invasions success: propagule pressure and disturbance. An anthropogenic disturbance that can promote invasions, by changing the amount of altered habitats and the extension of edges between altered and native habitats, is habitat loss. Despite the recognized importance of propagule pressure and disturbance, few studies have simultaneously investigated these factors, and those that did so present limitations, such as small spatial scales and correlations between drivers, impairing our understanding of the relative importance and interactions between these drivers. Dogs are the most abundant carnivores worldwide; in rural areas, most are free ranging, interacting and affecting native species through predation, disease transmission and competition. Using a camera trap dataset and censuses of dog populations obtained across a 300,000-ha Atlantic forest region, we evaluated the relative importance and interactions of propagule pressure and disturbance as drivers of dog invasion. We selected 12 2830-ha landscapes, ranging from 10 to 50% remaining native forest. Within each, we selected through a random-stratified sample 8 forest sites where a camera trap was set for &sim;42 consecutive days. All households in each landscape were visited to count the number of dogs. Propagule pressure was quantified as the density of raised dogs, and mean and median distances between locations where dogs were raised and the nearest forest; and disturbance as the proportion of the landscape occupied by native forest and by total forest (native and exotic), and edge extension between native forest and open areas. By identifying individual dogs in the photos and considering each landscape as a sampling unit, we compared through AICc N-mixture models to estimate the abundance of dogs within forests, considering imperfect detection. The only selected model indicates that dog abundance in forests is higher where the density of raised dogs is higher and where total forest cover is lower (&omega;i=0.82). Density of raised dogs was more important than the spatial distribution of individuals, and total forest cover more important than edge extension, in determining the abundance of invading dogs. The estimated dog abundance varied from 12 to 79 (30.9 ± 19.5), and the proportion of raised dogs that invade forests from 6 to 21% (12 ± 6%), across landscapes. Our results indicate that habitat loss is as important as propagule pressure in driving the invasion of native forests by dogs, but their effects are additive rather than synergic. Given that dogs frequently make long movements in open areas, we hypothesize that dog vagility is the cause of the negligible effect of spatial distribution of raised individuals on invasion, and that forests represent barriers to these movements, making the effect of forest cover more important than the effect of edge extension (more related to the extension of access to forests). Moreover, the number and proportion of invading dogs are impressive, ranking dogs as the most abundant carnivore in forest remnants. Together with the known severe impacts of dogs on native species, these numbers suggest the urgency of action plans for controlling dog invasion. Beyond the traditional population control, landscape context should be taken into account within strategies to reduce impacts of dogs. Highly-deforested landscapes should be prioritized, and maintaining and restoring forests should be valued also by their negative effects on biological invasions. Finally, given the observed associations between dog invasion and both habitat loss and density of dogs and human populations, we suggest that at least part of the negative effects on native mammals currently attributed to deforestation and hunting can be caused by dog invasion

Escherichia coli enterohemorrágicas (EHEC) que possuem a Ilha de Patogenicidade LEE são importantes patógenos humanos. A habilidade de adesão, invasão e perfil genético têm sido estudados, já que sorotipos que não possuem LEE tem sido isolados de pacientes com doença severa e intracelularmente. Das nove amostras relacionadas com doença, quatro (44.5%) apresentaram stx2+. Todas foram positivas para o gene lpfA e iha, e negativas para toxB. Três (33,3%) apresentaram saa e cinco hly. A maioria apresentou padrão de adesão difusa e invasão negativa em células HEp-2. Em CaCO-2 apresentaram aderência com variados graus de intensidade, e a maioria das amostras testadas apresentou invasão maior que 3,3%. Frente ao inibidor de polimerização de actina citocalasina D, houve significativa redução nos níveis de invasão, sugerindo que estas amostras utilizam um mecanismo da célula hospedeira para internalização, e que provavelmente, fatores de virulência como adesinas, favorecem a adesão das mesmas, compensando a ausência do LEE, e facilitando a instalação da infecção. / Enterohaemorrhagic Escherichia coli (EHEC) that possess the pathogenic island LEE are important human pathogens. The adhesion ability, invasion and genetic profile have been studied, since serotypes that do not possess LEE have been isolated from humans with severe disease and found intracellular. Nine strains related with SHU, four (44,5%) were stx2+. All strains were positive for IpfA and iha genes and negative for toxB. Three (33,3%) showed saa and five hly. The most strains showed a diffusely adhesion pattern and negative invasion in HEp-2 cells. It presented various degrees of adhesion, and the most tested strains showed invasion high than 3,3% in CaCO-2. That was a significant reduction of invasion in the presence of actin polymerization inhibitor Citochalasin D, suggesting that these strains use a host cell mechanism to invade, and probably virulence factors, like adhesins, favors this adhesion and compensate LEE absence, promoting the installation of infection.