A Study on the Capacity of Normal and talpid3 Mutant Myogenic Cells to Migrate in Fowl Embryonic Wing Buds

1. The ability of myogenic cells to migrate within chick wing bud was investigated using quail cell markers. Fragments of quail wing buds containing myogenic cells of somitic origin were excised from stage 20-26 H. H. embryos and olthotropically implanted into chick wing buds in ovo. The chimaeric limbs were fixed for analysis at daily intervals. It was not until after the second day of implantation that quail cells started migrating out of the graft sites. Quail chondrocytes were found at the graft sites but they were non invasive. After the third day of implantation, quail cells were detected in most of the muscle regions in the zeugopod, but it was not until after the fourth day that quail cells were discernible in the autopod. Myogenic cell migration was exclusively in a proximodistal direction, with very little or no concurrent movement in the opposite direction

Excess caffeine exposure impairs eye development during chick embryogenesis

Caffeine has been an integral component of our diet and medicines for centuries. It is now known that over consumption of caffeine has detrimental effects on our health, and also disrupts normal foetal development in pregnant mothers. In this study, we investigated the potential teratogenic effect of caffeine over-exposure on eye development in the early chick embryo. Firstly, we demonstrated that caffeine exposure caused chick embryos to develop asymmetrical microphthalmia and induced the orbital bone to develop abnormally. Secondly, caffeine exposure perturbed Pax6 expression in the retina of the developing eye. In addition, it perturbed the migration of HNK-1(+) cranial neural crest cells. Pax6 is an important gene that regulates eye development, so altering the expression of this gene might be the cause for the abnormal eye development. Thirdly, we found that reactive oxygen species (ROS) production was significantly increased in eye tissues following caffeine treatment, and that the addition of anti-oxidant vitamin C could rescue the eyes from developing abnormally in the presence of caffeine. This suggests that excess ROS induced by caffeine is one of the mechanisms involved in the teratogenic alterations observed in the eye during embryogenesis. In sum, our experiments in the chick embryo demonstrated that caffeine is a potential teratogen. It causes asymmetrical microphthalmia to develop by increasing ROS production and perturbs Pax6 expression

PTEN is involved in modulation of vasculogenesis in early chick embryos

Summary PTEN is a tumor suppressor gene that is mutated and/or deleted in many types of tumor. This gene also plays a very distinct role in the early stages of embryonic development such as cell migration, proliferation and migration. Nevertheless, little is known of the function of PTEN in vasculogenesis during chick embryonic development. In this study, we used in situ hybridization to first demonstrate the expression pattern of PTEN during gastrulation. PTEN was found mainly expressed in the blood islands of area opaca, the neural tube and mesodermal structures. Overexpression of PTEN obstructed the epithelial–mesenchymal transition (EMT) process in the primitive streak. EMT is the first prerequisite required for the emigration of hemangioblasts during vasculogenesis. When PTEN expression was silenced, we observed that it produced an adverse effect on mesodermal cell emigration to the extra-embryonic blood islands. In addition, we also demonstrated that even if the perturbed-PTEN cells did not affect the formation of blood islands, migrant mesodermal cells overexpressing wt PTEN-GFP had difficulties integrating into the blood islands. Instead, these cells were either localized on the periphery of the blood islands or induced to differentiate into endothelial cells if they managed to integrate into blood islands. Development of the intra-embryonic primary vascular plexus was also affected by overexpression of PTEN. We proposed that it was elevated PTEN lipid phosphatase activity that was responsible for the morphogenetic defects induced by PTEN overexpression. In this context, we did not find PTEN affecting VEGF signaling. In sum, our study has provided evidence that PTEN is involved in vasculogenesis during the early stages of chick embryo development

Diversidade e Estrutura Genéticas de Bryconamericus aff. Iheringii (Characiformes: Characidae) na Área de Influência do Reservatório da Itaipu

Trabalho de Conclusão de Curso apresentado ao Instituto Latino-Americano de Ciências da Vida e Natureza da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Bacharel em Ciências Biológicas – Ecologia e Biodiversidade.A diversidade genética é necessária para que as populações evoluam e se adaptem às mudanças ambientais, e comumente, está distribuída em um padrão dentro e entre populações que é referido como estrutura genética. O isolamento e a existência de poucos caminhos migratórios entre águas doces implicam na estruturação genética, principalmente, para peixes que possuem baixa mobilidade. Peixes de pequeno porte (≤ 15 cm de comprimento), que habitam riachos, representam, no mínimo 50% de toda a ictiofauna sul-americana e apresentam um alto grau de endemismo, devido, em parte, à sua baixa capacidade de deslocamento. Neste contexto, o presente trabalho objetivou avaliar a diversidade e a estrutura genéticas do caracídeo Bryconamericus aff. iheringii na área de influência do reservatório da Itaipu Binacional. Para isto, foram analisados 47 espécimes, 23 coletados em riachos da margem direita (Paraguai) e 24 coletados em riachos da margem esquerda (Brasil) do reservatório da Itaipu. Para acessar sua diversidade genética, foi empregado o marcador molecular D-loop, sendo estimado o número de haplótipos, os índices de diversidade haplotípica e nucleotídica e o nível de estruturação entre as diferentes amostras. B. aff. iheringii apresentou níveis de diversidade genética dentro do padrão relatado para a espécie, com moderados (amostras do Paraguai) a altos (amostras do Brasil) níveis de diversidade, o que se deve, sobretudo, ao fato de que quase todos os riachos paraguaios analisados são de uma única microbacia, enquanto os riachos brasileiros são de quatro microbacias diferentes. As populações não parecem ter respondido a eventos drásticos recentes, pois mesmo as presentes em regiões sob a pressão de atividades agrícolas, mostram variações no DNA mitocondrial. Foram encontrados altos níveis de estruturação genética entre o conjunto de amostras paraguaio e brasileiro e entre as microbacias dentro de cada país, o que se deve, principalmente, aos processos de colonização destas drenagens, os quais possivelmente envolvem fundadores com diferentes linhagens haplotípicas. Além disso, parece plausível que o rio Paraná (reservatório da Itaipu) funciona como uma barreira ao fluxo gênico entre as diferentes margens e entre suas microbacias. Deste modo, a identificação de linhagens é de grande importância, pois a manutenção da diversidade genética de uma espécie depende de sua preservação. Considerando a importância de estudos genético-populacionais para a conservação de espécies, espera-se que este trabalho possa servir como base para futuros estudos mais amplos com peixes de riachos

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London