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Pneumococcal phages as vehicles of virulence


Research objectives and content
The study and characterisation of Streptococcus pneumoniae bacteriophages has been hampered, mainly, due to the technical difficulty to visualise the plaques of phages and to obtain mutants. The CIB lab in Madrid has been able to study, in great detail, the characteristics of four groups of pneumococcal phages, including the whole sequencing and functional organisation of Cp-1 phage, carried out recently. On the other hand, the capsular polysaccharide is the main virulence factor of pneumococcus, and phages capable to infect pneumococcal encapsulated strains have not been described up to now and its isolation would bring about advantages with respect to the putative degradation of the pneumococcal capsular polysaccharides through appropriate enzymes. Isolation of these phages constitutes the main aim of this project. We also plan to carry out a systematic analysis of Iysogenic strains in order to correlate the most relevant clinical pneumococcal strains with the presence in these strains of temperate phages. Furthermore, we plan to study the Iysis mechanism of phage omega2 which presents peculiar characteristics compared to the other pneumococcal phages.
Training content (objective, benefit and expected impact)
The proposed work dealing with Streptococcus pneumoniae bacteriophages present a number of advantages. The thematics developed in this work and during my thesis are related enough so that I can be rapidly efficient in the research project. Nevertheless, the general domains are very different (medical, _nology). This would lead to greatly widening my initial formation. The study of the Iysis system has beer initiated during my thesis for an _nococcus _ni phage. The proposed work allows to increase the knowledge of such system. The CIB lab in Madrid is very competent in this subject, as proved by a large number of publications. Moreover, I will have the opportunity to acquire some techniques, particular!, concerning protein purification.In short, the benefit of this post-doctoral stay should be a widening of my initial formation and acquisition and development of practical competence.


144,Velázquez 144
28071 Madrid