Bordetella pertussis TonB, a Bvg-independent virulence determinant.
In: Infection and immunity, Jg. 68 (2000-04-01), Heft 4, S. 1919-27
Online
academicJournal
Zugriff:
In gram-negative bacteria, high-affinity iron uptake requires the TonB/ExbB/ExbD envelope complex to release iron chelates from their specific outer membrane receptors into the periplasm. Based on sequence similarities, the Bordetella pertussis tonB exbB exbD locus was identified on a cloned DNA fragment. The tight organization of the three genes suggests that they are cotranscribed. A putative Fur-binding sequence located upstream from tonB was detected in a Fur titration assay, indicating that the tonB exbB exbD operon may be Fur-repressed in high-iron growth conditions. Putative structural genes of the beta-subunit of the histone-like protein HU and of a new two-component regulatory system were identified upstream from tonB and downstream from exbD, respectively. A B. pertussis DeltatonB exbB::Km(r) mutant was constructed by allelic exchange and characterized. The mutant was impaired for growth in low-iron medium in vitro and could not use ferrichrome, desferal, or hemin as iron sources. Levels of production of the major bacterial toxins and adhesins were similar in the TonB(+)/TonB(-) pair. The DeltatonB exbB mutant was still responsive to chemical modulators of virulence; thus, the BvgA/BvgS two-component system is not TonB dependent. Nevertheless, in vivo in the mouse respiratory infection model, the colonization ability of the mutant was reduced compared to the parental strain.
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Bordetella pertussis TonB, a Bvg-independent virulence determinant.
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Autor/in / Beteiligte Person: | Pradel, E ; Guiso, N ; Menozzi, FD ; Locht, C |
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Zeitschrift: | Infection and immunity, Jg. 68 (2000-04-01), Heft 4, S. 1919-27 |
Veröffentlichung: | Washington, DC : American Society For Microbiology ; <i>Original Publication</i>: [Bethesda, Md.] American Society for Microbiology., 2000 |
Medientyp: | academicJournal |
ISSN: | 0019-9567 (print) |
DOI: | 10.1128/IAI.68.4.1919-1927.2000 |
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