Produção de um agente de controlo biológico recorrendo a subprodutos da indústria agro-alimentar

Dissertação de mest., Biologia Molecular e Microbiana, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011

Contributos para o estudo da clorose férrica

Dissertação de mest., Hortofruticultura, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2013

Screening for biological activities with application in aquaculture in halophytes from the Algarve coastline

Infectious diseases often hamper the production of aquatic organisms in aquaculture systems, causing economical losses, environmental problems and consumer safety issues. The conventional way aquaculture producers had to control pathogens was by means of synthetic antibiotics and chemicals. This procedure had consequences in the emergence of more resilient pathogens, drug contamination of seafood products and local ecosystems. To avoid the repercussions of antibiotic use, vaccination has greatly replaced human drugs in western fish farms. However there is still massive unregulated antibiotic use in third world fish farms, so less expensive therapeutic alternatives for drugs are desperately needed. An alternative way to achieve disease control in aquaculture is by using natural bioactive organic compounds with antibiotic, antioxidant and/or immunostimulant properties. Such diverse biomolecules occur in bacteria, algae, fungi, higher plants and other organisms. Fatty acids, nucleotides, monosaccharides, polysaccharides, peptides, polyphenols and terpenoids, are examples of these substances. One promising source of bioactive compounds are salt tolerant plants. Halophytes have more molecular resources and defence mechanisms, when compared with other tracheophytes, to deal with the oxidative stresses of their habitat. Many halophytes have been used as a traditional food and medical supply, especially by African and Asian cultures. This scientific work evaluated the antibiotic, antioxidant, immunostimulant and metal chelating properties of Atriplex halimus L., Arthrocnemum macrostachyum Moric., Carpobrotus edulis L., Juncus acutus L. and Plantago coronopus L., from the Algarve coast. The antibiotic properties were tested against Listonella anguillarum, Photobacterium damselae piscicida and Vibrio fischeri. The immunostimulant properties were tested with cytochrome c and Griess assays on Sparus aurata head-kidney phagocytes. J. acutus ether extract inhibited the growth of P. damselae piscicida. A. macrostachyum, A. halimus, C. edulis, Juncus acutus and P. coronopus displayed antioxidant, copper chelating and iron chelating properties. These plants show potential as sources of bioactive compounds with application in aquaculture and in other fields.

Synthesis and evaluation of polymer nanoparticles for delivery in RPE cells

Ocular pathologies are among the most debilitating medical conditions affecting all segments of the population. Traditional treatment options are often ineffective, and gene therapy has the potential to become an alternative approach for the treatment of several pathologies. Methacrylate polymers have been described as highly biocompatible and are successfully used in medical applications. Due to their cationic nature, these polymers can be used to form polyplexes with DNA for its delivery. This work aims to study the potential of PDMAEMA (poly(2-(N,N’-dimethylamino)ethyl methacrylate)) as a non viral gene delivery system to the retina. The first part of this work aimed to study the potential for gene delivery of a previously synthesized PDMAEMA polymer of high molecular weight (354kDa). In the second part, we synthesized by RAFT a PDMAEMA with a lower molecular weight (103.3kDa) and similarly, evaluated its ability to act as a gene delivery vehicle. PDMAEMA/DNA polyplexes were prepared at 5, 7.5, 10, 12.5 and 20 nitrogen/phosphorous (N/P) ratio for the 354kDa PDMAEMA and at 5 and 7.5 for the 103.3kDa PDMAEMA. Dynamic light scattering and zeta potential measurements confirmed the nanosize and positive charge of polyplexes for all ratios and for both polymers. Both high and low Mw PDMAEMA were able to efficiently complex and protect DNA from DNase I degradation. Their cytotoxicity was evaluated using a non-retinal cell line (HEK293) and a retinal pigment epithelium (RPE) cell line (D407). We have found that cytotoxicity of the free polymer is concentration and time dependent, as expected, and negligible for all the concentrations of the PDMAEMA-DNA polyplexes. Furthermore, for the concentrations to be used in vivo, the 354kDa PDMAEMA showed no signs of inflammation upon injection in the intravitreal space of C57BL/6 mice. The transfection efficiency, as evaluated by fluorescence microscopy and flow cytometry, showed that the D407 retinal cells were transfected by polyplexes of both high and low Mw PDMAEMA, but with varied efficiency, which was dependent on the N/P ratio. Althogether, these results suggest that PDMAEMA is a feasible candidate for non-viral gene delivery to the retina, and this work constitutes the basis of further studies to elucidate the bottleneck in transfection and further optimization of the material.

Nanopartículas poliméricas com aplicação na administracão pulmunar de proteínas

O interesse da indústria farmacêutica na administração de biomoléculas não é recente, uma vez que desde que a insulina foi comercializada pela primeira vez em 1923, temos vindo a assistir ao aumento do número de trabalhos relacionados com as aplicações terapêuticas deste tipo de moléculas. No entanto, a aplicação terapêutica destas moléculas regista várias limitações devidas essencialmente à sua estrutura e propriedades físico-químicas, bem como à sua estabilidade. Com o aparecimento e evolução da nanomedicina, tornou-se possível o desenvolvimento e funcionalização de nanopartículas transportadoras de biomoléculas, dotando este sistema de um enorme potencial para várias terapêuticas. As vantagens deste tipo de sistema de administração incluem a proteção das moléculas ativas encapsuladas, proporcionando um aumento da biodisponibilidade, e tornam também possível a administração das biomoléculas por vias menos invasivas. Esta dissertação tem por objetivo explorar as potencialidades da via pulmonar para a administração de biomoléculas. Neste sentido, serão focadas os vários tipos de nanopartículas de polímeros naturais e sintéticos como sistema de administração com aplicação na administração por esta via.

Metodologias de síntese de tetraoxanos com potencial utilização em química medicinal

Dissertação de Mestrado, Ciências Farmacêuticas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Síntese de Biosílica em fibras de policaprolactona, produzidas por electrospinning, a partir da imobilização de Cys-tag Silicateína-α

Dissertação de Mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Establishment of a protocol for the cryopreservation of cell sheets of adipose tissue stem cells

Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2016

Design and synthesis of novel quinolones directed to the Plasmodium falciparum bc1 protein complex

Tese de Doutoramento, Química, Especialização em Química Orgânica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016