| Popis: |
Actinobacillus actinomycetemcomitans (Aa) is a microaerophilic, gram-negative oral pathogen. Congo red and hemin biding assays showed that all tested strains were able to bind this stain and iron-containing compound, respectively. Inspection of the HK1651 genome indicated that this binding activity could be associated with the presence and expression of hms-like genes, which code for similar functions in other pathogens such as Yersinia pestis. A DF2200N derivative in which hmsF was disrupted by insertion mutagenesis showed a large reduction in hemin and Congo red binding activity. Iron-utilization assays showed no significant difference in the ability of the parental strain and the hmsF insertion derivative to use hemin under chelated conditions. These observations are in agreement with the presence of an hms-like locus in the genome of Aa, which seems to be involved in the interaction of cells with hemin but not the utilization of this compound as an iron source. |
