| 1. |
- Mangold, Monika, et al.
(författare)
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Synthesis of group A streptococcal virulence factors is controlled by a regulatory RNA molecule.
- 2004
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 53:5, s. 1515-1527
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Tidskriftsartikel (refereegranskat)abstract
- The capacity of pathogens to cause disease depends strictly on the regulated expression of their virulence factors. In this study, we demonstrate that the untranslated mRNA of the recently described streptococcal pleiotropic effect locus (pel), which incidentally contains sagA, the structural gene for streptolysin S, is an effector of virulence factor expression in group A beta-haemolytic streptococci (GAS). Our data suggest that the regulation by pel RNA occurs at both transcriptional (e.g. emm, sic, nga) and post-transcriptional (e.g. SpeB) levels. We could exclude the possibility that the pel phenotype was linked to a polar effect on downstream genes (sagB-I). Remarkably, the RNA effector is regulated in a growth phase-dependent fashion and we provide evidence that pel RNA expression is induced by conditioned media.
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| 2. |
- Schmitz, Franz-Josef, et al.
(författare)
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Toxin-gene profile heterogeneity among endemic invasive European group A streptococcal isolates.
- 2003
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 188:10, s. 1578-1586
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Tidskriftsartikel (refereegranskat)abstract
- We determined the toxin-gene profiles of 239 endemic, invasive group A streptococcal (GAS) isolates that circulated, within a 5-year period, in European university hospitals. Profiling was performed by use of multiplex polymerase chain reaction that screened for 9 streptococcal pyrogenic exotoxins (speA, speB, speC, speF, speG, speH, speJ, ssa, and smeZ). Analysis revealed that invasive GAS isolates do not share a common toxin-gene profile. Although all emm types were characterized by several different toxin-gene profiles, a predominance of 1 or 2 toxin-gene profiles could be observed, reflecting that a few invasive clones have spread successfully throughout the world. Remarkably, statistical pair-wise analysis of individual toxin genes revealed that strains that did not share the predominant profile still showed a nonrandom distribution of key toxin genes characteristic of the specific emm type. This could indicate that M proteins function, directly or indirectly, as barriers for horizontal gene exchange.
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