Sérgio Filipe is microbiologist interested in learning how bacterial cells divide and are able to proliferate in challenging environments, such as in the presence of antibiotics or while facing the host immune system. During his Ph. D., he questioned the strategies used by Streptococcus pneumoniae to resist penicillin, a beta-lactam antibiotic, under the supervision of Prof. Alexander Tomasz and of Prof. Hermínia de Lencastre (The Rockefeller University, New York). In 2001, he joined the laboratory of Prof. David Sherratt (University of Oxford), supported by an EMBO long-term fellowship, and became familiar with bacterial cell biology techniques that permit the visualization of different fluorescent targets in dividing Escherichia coli. While in Oxford, he started to collaborate with Prof. Petros Ligoxygakis, who had recently joined the Department of Biochemistry and was using Drosophila melanogaster to understand the innate immune response to fungal infections. Since then, they have been questioning how Drosophila flies are capable of recognizing invading bacteria and, more recently, how bacteria can evade detection of components present at their surface. Between 2004 and 2020, Sérgio Filipe led the research group of Bacterial Cell Surfaces and Pathogenesis present at the Associated Laboratory of ITQB (Instituto de Tecnologia Química e Biológica). While at ITQB, he became Principal Investigator, supported by the Investigador FCT programme. In 2015, Sergio joined the Department of Life Sciences, NOVA School of Science and Technology, as Assistant Professor, where he teaches different courses of Molecular Biology and other short curricular units. Since 2015, he has been leading the research group of Bacterial Cell Surfaces and Pathogenesis present at UCIBIO (Applied Molecular Biosciences Unit). Sergio has coordinated several R&D projects with various national and international collaborations and he has supervised, or he is the current supervisor, of 12 PhD and 15 Master students. He co-authored more than 49 peer-reviewed publications in different journals, 15 of which in multidisciplinary journals such as PNAS (5), EMBO J (3), PLoS Pathogens (6), Nature (1), Nature Communications (1), Cell Reports (1) and eLife (1). Sérgio Filipe is focused on understanding how bacteria assemble their cell surface. This process is carried out by a multistep mechanism that ensures (1) the robustness of the bacterial cell surface, which allows bacteria to withstand the intense osmotic pressures they are normally subjected to and (2) the concealment of the peptidoglycan (PGN) molecule, a major component of any bacterial cell surface and a telltale molecule that flags bacteria to the host innate immune system. The questions currently being tackled are: - How do Staphylococcus aureus bacteria, and other bacteria, conceal their PGN from detection PGN receptors, such as those produced by the Drosophila innate immune system? - How do Streptococcus pneumoniae bacteria express their ability to resist beta-lactam antibiotics, which prevent synthesis of the PGN macromolecule, and decorate it with capsular polysaccharides, which is a major pneumococcal virulence factor? - How do host receptors recognize PGN molecules and discriminate those produced by bacterial pathogens vs bacterial symbionts?