Sumários

Symbiosis and nitrogen fixation

10 outubro 2018, 09:00 Jorge Humberto Gomes Leitão

The topic of fixation of nitrogen by bacteria was introduced as an example of a symbiotic interaction of bacteria with their hosts, focusing on the problem of nitrogen source availability for organisms and the role played by bacteria that convert atmospheric nitrogen into ammonia or nitrate. The key steps , molecules and genes involved in the initial recognition of bacteria and host until the formation of mature symbiosomes and nitrogen fixing nodules were presented and discussed.


Post-transcriptional regulation of bacterial gene expression

8 outubro 2018, 09:00 Jorge Humberto Gomes Leitão

The distinct levels at which gene expression regulation in bacteria can occur were presented and discussed.  The concept of coding and non-coding RNA was introduced. Small non-coding regulatory RNAs (sRNAS) and their modes of action involving the RNA chaperone Hfq were presented.  Several examples of sRNAs, including Spot42, DsrA, and RyhB were presented. An overview of sRNAs and their biological roles in E. coli were presented. Results from research performed at iBB on sRNAs and Hfq  from bacteria of the Burkholderia cepacia complex were presented and discussed


Heat shock response. Extracytoplasmic stress response.

3 outubro 2018, 09:00 Jorge Humberto Gomes Leitão

The sigma 32 alternative sigma factor and its involvement in heat shock response were presented and discussed. The extracytoplasmic stress response and the sigma E/anti-sigma E regulation were presented and discussed. Alternative sigma factors were introduced and discussed.


Bacterial gene expression regulation by Quorum-sensing

1 outubro 2018, 09:00 Jorge Humberto Gomes Leitão

The quorum sensing mode of bacterial gene expression regulation was presented, focusing on the example of light emission by bacterial symbiosis with deep-sea fish. The lux system was introduced. The different types of signaling molecules used by bacteria was presented and discussed. The chemical nature of molecules and the differences between gram-negative and gram-positive bacteria quorum sensing systems were presented and discussed. The rhl, pqs and las quorum sensing systems of Pseudomonas aeruginosa were presented. Quorum sensing systems from bacteria of the Burkholderia genus were also presented.

The mode of growth of microorganisms as biofilms was introduced.  The mechanisms underlying biofilm formation were presented and discussed. Impacts of biofilms in water distribution systems and as causes of persistent infections in humans were presented and discussed. The quorum quenching concept was introduced. Some examples of antagonists of quorum sensing and of enzymes capable of degrading signals were presented. 


Class canceled

26 setembro 2018, 09:00 Jorge Humberto Gomes Leitão

Class canceled