ITQB: BCSP - PhD Theses
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- Synthesis and host recognition of Staphylococcus aureus peptidoglycanPublication . Covas, Gonçalo; Filipe, Sérgio Joaquim Raposo"Bacteria are able to establish relationships with other organisms, which may be temporary, as in a bacterial infection, or long-term, as in symbiosis. From the interplay between different organisms emerged the concept of “identity”, i.e. the need to distinguish “self” from “non-self”. Multicellular organisms have developed immune systems responsible for the detection of “non-self” organisms that lead to the activation of appropriate responses to maintain the organism in a state of homeostasis. In opposition, bacteria have developed mechanisms (virulence factors) to avoid their identification as harmful, in order to assure their survival within the host. (...)"
- Peptidoglycan synthesis and penicillin resistance in Streptococcus pneumoniaePublication . Narciso, Ana Rita da Cruz; Filipe, Sérgio Raposo"Resistance to penicillin in Streptococcus pneumoniae involves remodelling of penicillin-binding proteins (PBPs), enzymes involved in the last stages of peptidoglycan (PGN) synthesis, which reduce the affinity of these targets to the antibiotic. However, the peptidoglycan composition has an important role in the expression of resistance to this antibiotic. The murMN operon in particular seems to play a critical role, since deletion lead to the complete abolishment of penicillin resistance, even in the presence of the remodelled PBPs. (...)"
- Bacteria present mechanisms to evade cellular and humoral responses mediated through peptidoglycan recognition by PGRP-SA and PGRP-LCPublication . Vaz, Filipa Baltazar da Costa; Filipe, Sérgio RaposoThe Host presents different innate immune components to fight bacterial infections, most of which are evolutionary conserved strategies. Conversely, Bacteria present numerous mechanisms of virulence and evasion, transversal to different bacterial species, that confer resistance or subvert the activity of the Host components. This thesis presents a study on how the Host perceives the Bacteria and reacts to them and how the Bacteria protect themselves from those responses.(...)
- Studies of the assembly of the Streptococcus pneumoniae capsular polysaccharidePublication . Henriques, Mafalda Soeiro Xavier; Filipe, Sérgio RaposoThe capsular polysaccharide (CPS), or capsule, is one of the main virulence factors of Streptococcus pneumoniae. This gram-positive bacterium can asymptomatically colonize the nasopharynx of healthy individuals, but it also has the capacity to spread to other parts of the host’s body and cause disease. The ability of pneumococcal bacteria to cause invasive disease is dependent upon the presence of the CPS, which surrounds the entire cell surface, protecting it from the host immune system.(...)
- Bacterial peptidoglycan biosynthesis and recognition by the innate immune systemPublication . Atilano, Magda; Filipe, Sérgio RaposoBacteria have to overcome numerous obstacles in order to invade and infect the host, and therefore have evolved sophisticated mechanisms to prevent their elimination, or detection, by the host immune system. The bacterial cell wall is essential for bacterial survival and central to different interactions between bacteria and the host. It is a dynamic and complex surface structure with a multitude of functions, ranging from acting as a structural scaffold or barrier against osmotic lysis, to being involved in cell adhesion.(...)