INVESTIGADORES
ECHENIQUE Jose Ricardo
congresos y reuniones científicas
Título:
Programmed cell death in Streptococcus pneumoniae is induced by acidic stress and regulated by quorum sensing.
Autor/es:
PIÑAS GE; CORTES PR; ECHENIQUE J
Lugar:
Bariloche
Reunión:
Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2003
Institución organizadora:
SAIB
Resumen:
In bacteria, programmed cell death mainly lead to cellular lysis,
and plays an important role in certain developmental process. In
S. pneumoniae, lysis is produced by the major autolysin LytA.
Our studies on acid tolerance response (Cortes et al., poster
presentation) showed that log-phase cells lysed when cultured at
pH 5.6 after 3 Hs of incubation at 37oC. With the aim to understand
the mechanism of acid-induced autolysis, we analysed mutants
with an altered lytic phenotype. Previously, we have described a
serine threonine kinase, StkP, whose mutant stkP::km showed
autolysis in log-phase and to be essential for competence
development activating comCDE transcription (Echenique et al.,
in revision). We analysed the impact of stkP::km mutant in acidinduced
autolysis, and it showed early autolysis compared with
wild-type. Considering that comCDE transcription is not activated
in the stkP::km mutant, we expected that comE::km mutant should
present the same phenotype. Interestingly, this mutant presented
no lysis at pH 5.6, however ciaR::spc, a response regulator mutant
that present hyper-expression of comCDE, lysed as early as
stkP::km. These results allow us to conclude that programmed
cell death is induced by an environmental condition like low pH,
and it?s controlled by a quorum sensing mechanism as ComCDE.
We also propose that StkP had a protector role against acid-induced
autolysis, independently of ComCDE pathway.