ITQB: MGMR - MA Dissertations
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- Tetrapyrrole Metabolism of Staphylococcus aureusPublication . Esteves Mota, Salomé; Videira, Marco; Saraiva, Lígia"Staphylococcus aureus is a commensal bacterium with its pathogenicity associated with toxin-mediated diseases, several infections, and the presence of iron-containing tetrapyrroles, Haem and Sirohaem which are crucial for survival within the human host enabling infection. Haem can be synthesised endogenously or acquired from the environment by haem uptake systems being essential for many bioprocesses. It can be synthesised via three different pathways: protoporphyrin-dependent pathway, sirohaem-dependent pathway, and coproporphyrin-dependent pathway. Sirohaem is involved in sulphate and nitrate reduction as a cofactor for sulphite and nitrite reductases, synthesised either by one, two or three enzymes: sirohaem synthase CysG (e.g., present in E. coli), met1 and met8 genes (e.g., present in fungi and bacteria) and the proteins UroM, P2D and ShfC (e.g., present in S. aureus).(...)"
- Haem uptake study in Helicobacter pylori clinical strains isolated from children with iron deficiency anaemiaPublication . Bernardino, Joana Rita de Sousa; Baes, Jordi; Oleastro, Mónica"Anaemia is a disease that results of reduced red blood cells or haemoglobin levels, limiting blood’s oxygen transport throughout the body, usually caused by the lack of nutrients. Iron deficiency anaemia (IDA) is a type of anaemia caused by the lack of iron, affecting 1.2 billion world’s population, according to a Global Burden of Disease Study (2016). Patients with IDA present paleness, fatigue, dyspnoea, and headache.(...)"
- Understanding how Streptococcus pneumoniae adapts to stresses imposed by innate immunityPublication . Martins do Rio, Ana Sofia; Carvalho, Sandra; Saraiva, Ligia"Streptococcus pneumoniae is a commensal microorganism in the human nasopharynx that can become pathogenic when invading sterile body regions, leading to difficult-to-treat infections due to strain diversity and antibiotic resistance. The innate immune response to S. pneumoniae is primarily driven by phagocytes like macrophages, which generate antimicrobial reactive oxygen species (ROS) and reactive nitrogen species (RNS). To survive, S. pneumoniae has evolved mechanisms to resist these stresses and relies heavily on glucose metabolism for survival at infection sites. While phosphotransferase systems (PTS) are linked to stress resistance in other Gram-positive bacteria, their role in the pneumococcus remains poorly understood.(...)"
- Study of iron metabolism in the human pathogen Acinetobacter baumanniiPublication . Moniz, Beatriz; Beas, Jordi; Saraiva, Lígia"Acinetobacter baumannii is a multidrug resistant nosocomial pathogen, that is considered by World Health Organization as a priority for research and development of new antibiotics. Iron is essential in all living organisms, as it is part of cofactors in proteins involved in multiple fundamental cellular processes. Iron is associated with proteins in Fe-S clusters, heme or mono/di-iron proteins. A. baumannii species have a variety of mechanisms for iron acquisition from the host environment, including heme uptake systems, siderophore secretion or iron passive diffusion through outer membrane porins. Cofactors such as heme and Fe-S clusters are synthesized by A. baumannii through the protoporphyrin-dependent branch and the ISC system, respectively. In this work, we aimed to study a possible link between proteins involved in heme biosynthesis and Fe-S cluster biogenesis pathways as well as understand how heme-bind proteins can acquire heme. For that, we focused on the interaction of proteins involved in the synthesis of Fe-S and heme cofactors, as well as proteins that harbor these cofactors for proper functioning.(...)"
- Studies of the RIC protein in Staphylococcus aureusPublication . Nunes, Ana Laura Veiga; Saraiva, Lígia"Repair Iron center (RIC) protein is a di-iron center containing protein widely distributed among bacteria that contributes to pathogen resistance. In Escherichia coli, RIC is able to donate iron for repairing of damaged iron sulfur clusters. Moreover, RIC protein confer resistance to Staphylococcus aureus exposed to reactive oxidative and nitrosative stresses in murine macrophages(...)"
- Carbon Monoxide Releasing Molecules - towards a novel antimicrobial therapeutic drugPublication . Mendes, Ana Sofia Soares; Saraiva, Lígia; Marques, Joana"Carbon monoxide releasing molecules (CORMs) are carbonyl organometallic complexes that liberate controlled amounts of carbon monoxide, which is a signalling and cytoprotective molecule important in human physiology and pathophysiology. Several studies in animals have shown that CORMs are beneficial in the treatment of cardiovascular diseases, inflammation and organ protection. Additionally, CORMs present antimicrobial properties. (...)"
- How Staphylococcus epidermidis and Staphylococcus aureus cope with oxidative and nitrosative stressPublication . Freitas, CS; Saraiva, Lígia"Staphylococcus epidermidis and Staphylococcus aureus are predominant colonizers of the human skin and important nosocomial pathogens. These pathogens form biofilms, mainly on implanted medical devices, that are resistant to antibiotics and to the chemicals produced by the host immune system. In particular, professional phagocytes of the innate immunity release toxic reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are highly damaging to pathogens, whose survival depends on their defense mechanisms.(...)"