Development and standardization of a protocol for sperm cryopreservation of two important commercial oyster species

Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015Aquaculture activities have a huge contribution for the world food production and their development is extremely necessary to answer to the lack of resources, especially to the demand for seafood. Bivalve production, especially Crassostrea angulata (Portuguese oyster) has been practiced from long ago, and although its production suffered several constraints, in recent years it has been increasing the interests in recovering production and in preserving nature populations. In this sense, new research needs to guarantee an efficient and economically viable production, contributing to a relatively new environmental concern: wild population restoration. Nowadays, pure wild populations of Crassostrea angulata are rare to find due to multiple factors that affected this oyster industry. Cryopreservation technology could promote alternative techniques to contribute for the resource management efficiency of the Portuguese oyster and associated economic activity. In this sense, standardization of procedures is important for Crassostrea genus. At the present there are no cryopreservation reports on Crassostrea angulata sperm, and therefore, one of the objectives of this work is to design a cryopreservation protocol for this species, testing the more adequate cryoprotectant solution, its ideal concentration, different freezing rates and types of containers. In parallel, this stablished protocol was applied in Crassostrea gigas and compared to other previously published for this species. Analysis of motility, viability, agglutination and fertilizations were used as guides for the establishment of the protocol in C. angulata. Moreover, ATP content, DNA fragmentation and lipid peroxidation were done in order to standardize the same protocol for both species. Movement analysis were assessed by CASA system, viability through common staining techniques and flow cytometer, agglutination was quantified according to the scale developed by Dong et al., (2007), ATP content determined by bioluminescence, Comet assay was performed to quantify the DNA fragmentation and lipid peroxidation determined spectrophotometrically by measuring the absorbance of the malondialdehyde (MDA). Significant differences were observed (p<0.05) for lipid peroxidation and fertilization trials whereas ATP content and fragmentation of DNA of the cryopreserved samples did not differ significantly from the control. In C. gigas, the same analysis were performed and did not reveal post-thaw quality differences in the samples cryopreserved with 10% DMSO. The established protocol revealed to be effective and with a low degree of cellular damage on C. angulata sperm and, at the same time, viable to apply in other species, such as Crassostrea gigas

The use of bacteriophages to control infectious biofilms

EMBO Conference on Viruses of Microbes III: Structure and Function - from Molecules to Communities (Programme and Abstract Book)info:eu-repo/semantics/publishedVersio

O potencial biotecnológico dos bacteriófagos na deteção e controlo de bactérias patogénicas

Os bacteriófagos (fagos) apresentam um imenso potencial biotecnológico com aplicação na saúde devido às suas características intrínsecas de reconhecimento e morte do hospedeiro que infetam (bactérias). A exploração destas características no desenvolvimento de métodos de deteção e de controlo de bactérias patogénicas é relativamente recente, embora a utilização de fagos como ferramentas de biologia molecular seja bastante antiga e a terapia fágica uma prática secular, actualmente limitada a alguns países

The use of bacteriophages to control biofilms

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/1096

The role of exopolymers in Sphingomonas paucimobilis attachment and biofilm formation

Exopolymers have an important role in biofilm formation, being involved in the initial adhesion events and influencing the biofilm characteristics. The results of a study with a strain of Sphingomonas paucimobilis that excretes a polysaccharide gum (gellan) has been used to exemplify the role of exopolymers in cell attachement and biofilm formation. The attachement results were interpreted throught the XDLVO theory and they revealed that exopolymers have a dual role in cell attachement by booth coating the substratum making adhesion favourable and by strengthing adeshion through the establishement of polymeric bridges. Exopolymers were also essential to the formation of Sphingomonas paucimobilis biofilms acting as scaffolds for bacterial proliferation. The physicochemical properties, the composition of the biofilm matrix and the cohesion forces within the biofilm were also conditioned by the presence of exopolymers

Bacteriophage-derived enzymes: from exploration to exploitation

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Bacteriophages are viruses infecting bacterial cells. During their replication cycle, these viruses cross the bacterial cell wall twice. Firstly, bacteriophages have to inject their genome across the cell wall to initiate infection. Secondly, they must exit the host cell at the end of the replication cycle to infect new host cells. The principal barrier to overcome is the polysaccharides that can either be extracellular (slime or capsules) or structural (peptidoglycan). For this, bacteriophages encode two specific enzymes, called depolymerases and endolysins, to degrade these polymers to enable either infection or lysis. [...]info:eu-repo/semantics/publishedVersio

Análise dos efeitos de fármacos no meio ambiente aquático: uso de biomarcadores

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências FarmacêuticasA ocorrência de fármacos no meio ambiente aquático é um assunto de atual e particular interesse para a comunidade científica. Diversos compostos de cariz farmacológico têm sido detetados em efluentes de estações de tratamento de águas residuais e consequentemente no compartimento aquático por todo o mundo. Alguns dos efeitos adversos causados por fármacos no compartimento aquático incluem toxicidade, desenvolvimento de resistência em bactérias patogénicas, genotoxicidade e desregulação endócrina. Num contexto de análise do risco ambiental, a utilização de diversos biomarcadores promete ser um indicador sensível que demonstra que o composto tóxico entrou no organismo, começou a ser distribuido nos tecidos/órgãos e está a começar a produzir efeitos tóxicos críticos. O objetivo deste trabalho foi identificar as consequências ambientais, e eventualmente de saúde pública, que resultam da contaminação do compartimento aquático por via de compostos farmacológicos inapropriamente libertados para o meio aquático, ou lixiviados nos esgotos domésticos como metabólitos secundários humanos, bem como referenciar formas de detetar os efeitos causados nos seres vivos fruto da exposição a estes compostos antrópicos. Particular ênfase foi dada a utilização dos biomarcadores enquanto ferramenta de análise ecotoxicológica. The occurrence of pharmaceuticals in the aquatic environment is a subject of current and particular interest to the scientific community. Several pharmacological compounds have been detected in wastewater treatment stations for wastewater and consequently in the aquatic compartment worldwide. Some of the adverse effects caused by these chemicals in the aquatic compartment include toxicity, development of resistance in pathogenic bacteria, genotoxicity and endocrine disruption. In the context of environmental risk analysis, the use of various biomarkers promises could be a sensitive indicator which shows that the toxic compound after entering the organism, and being distributed in tissues/organs, is starting to produce critical toxic effects. The aim of this study was to identify the environmental problems and public health issues, that result from contamination of the aquatic compartment via the direct release of pharmacological compounds into the water, or through human secondary metabolites in usually found in wastewater. Particular emphasis was given to the use of biomarkers as ecotoxicological analysis tools

Influências de uma Gestão Participativa Escolar no cotidiano educacional no município de Bom Retiro do Sul/RS-Brasil

Esta monografia está circunscrita fundamentalmente às contribuições e interações de um processo de gestão participativa nas ações pedagógicas dos educandários municipais que possuem alunos do 1º ao 5º Ano do Ensino Fundamental, em regime integral de atividades, no município de Bom Retiro do Sul. O estudo descreve reflexões sobre a gestão participativa e seu contexto, oportunizando múltiplos olhares frente às suas relações sociais. Diante do exposto, o objetivo geral que norteou as linhas de ação oportunizou verificar a importância e os benefícios existentes na Gestão Participativa e no cotidiano escolar dos educandários que atendem os alunos em tempo integral. Utilizou-se como metodologia a pesquisa qualitativa, etnográfica, ocasional e de campo, com análise de informações coletadas via entrevista semi-estruturada. O estudo sobre Gestão Participativa fundamentou-se nas linhas de Paro (2000 e 2010), Lück (2010), Hora (1997), e Oliveira (1997), paralelamente oportunizando um resgate histórico baseado na legislação da Constituição Federal (1998), PNE (2014) e LDBN (1996), alicerçado nas abordagens de Ribeiro (1978), Reed (1997), Braverman (1987), Junquilho (2012), Bartnik (2012), e Chiavenato (2010). O contexto escolar transcende relações sociais pertinentes ao contexto, alicerçados nos estudos de Camargo (2006), Oliveira (1997), Ferreira (2008), Hora (1997), Faria (2009), Hattge (2006 e 2007) e Goldmeyer (2010). Após análise da realidade nos educandários, constatam-se, parcial e integralmente, as contribuições positivas que a gestão participativa aponta no processo significativo do ensino. As articulações de uma gestão participativa favorecem a qualidade educacional, tornando os educandários palco de situações significativas de ensino e de aprendizagem, oportunizando interações sociais pertinentes ao contexto no qual estão inseridas