Gene regulation in Streptococcus pneumoniae - RePub - Erasmus ...

Chapter 6
attenuated phenotype. After 48h throughout 96h of infection, mice infected with the glnA-
mutant had significantly lower bacterial loads in the nasopharynx (Fig. 3A). At 192h the
difference was still present, but it was not statistically significant.
Figure 2. In vitro adherence of pneumococcal mutants to the human pharyngeal epithelial cell line Detroit 562.
All strains were constructed in a D39Δcps genetic background. The adherence of the mutants is given as the
percentage relative to the wild-type. * indicates P < 0.05.
Neither the glnP-mutant nor the gdhA-mutant was significantly attenuated during 192h
of colonization, whereas the glnA-glnP double mutant was significantly attenuated after 24h
of colonization and severely from 48h onwards to the point of being cleared at 192h. Due to a
relatively low colonization level of the wild-type at 96h, no significant difference was reached
at this time point (Fig. 3B). The more severe attenuation of the glnA-glnP double mutant in
comparison to that of the glnA-mutant is suggestive of an additive effect of the glnP mutation
to the colonization phenotype of ΔglnA.
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