Sumários

Microbial Mechanisms of Pathogenicity_I

5 outubro 2015, 08:30 • Arsénio do Carmo Sales Mendes Fialho

Important concepts in microbial pathogenesis:

Abundance / diversity / distribution of bacteria in nature.Pathogenesis / virulence factors, type of pathogens . Mechanisms of Pathogenicity . The Movement of Microbes into Hosts: Adherence. Avoidance of host defense mechanisms.

Post-transcriptional regulation of gene expression by sRNAs in prokaryotes

30 setembro 2015, 09:00 • Jorge Humberto Gomes Leitão

Discussion of the flux of genetic information and the various levels of regulation of gene expression. Coding and non-coding RNAs. Characteristics of bacterial sRNAs. Mechanisms of action of sRNAs. Examples of sRNAs and their biological roles: Spot42, GcvB, RhyB, OxyS. Presentation of the experimental strategy used to identify sRNAs from bacteria of the Burkholderia cepacia complex.

Quorum quenching. Alternative sigma factors.

28 setembro 2015, 08:30 • Jorge Humberto Gomes Leitão

The quorum sensing and strategies to combat the phenomena: quorum quenching. Quorum quenching strategies. Antagonists and lactonases.

Alternative sigma factors. The role of sigma subunit in driving RNA polimerase towards specific promoters. More relevant alternative sigma factors of E. coli. The sigma 70, sigmaD, SigmaE sigmaH, sigma N. Molecular mechanisms of sigma H in the context of heat shock response and of sigma E in extracytoplasmatic stress response. 

Regulation f gene expression by quorum sensing

23 setembro 2015, 09:00 • Jorge Humberto Gomes Leitão

Description of the phenonmenon of quorum sensing regulation of gene expression in bacteria. Emission of light by Vibrio fisheri: the Lux operon, synthesis of signaling molecules and mechanism of quorum sensing regulation of light emission. Chemical structures of molecules used by gram-positive and gram-negative bacteria as signaling molecules. Examples of phenotypes regulated by quorum sensing: twitching motility in Pseudomonas aeruginosa, virulence factors production, biofilms formation. Discussion on the events of biofilm formation. Discussion of the trojan horse concept of quorum sensing regulation of virulence gene expression.

Adaptation to environmental changes - Two component regulatory systems

21 setembro 2015, 08:30 • Jorge Humberto Gomes Leitão

Presentation and discussion of the two component regulatory systems (TCRS) use dby bacteria to sense and adapt to environmental changes. Discussion of the mechanisms involved in the histidine kinase sensor phosphorylation, phosphorylation of the response regulator, and role of the response regulator as transcription factor. Discussion of the TCRS systems used by E. coli to adapt to osmolarity changes, phosphate limitation, and oxygen availability. The EnvZ/OmpR, PhoU/PhoR, ArcA/ArcB and NarP/NarQ, NarX/NarL systems. Roles played by cytoplasmatic sensor proteins in oxygen sensing.