Affiliation:
1. Department of Odontology/Cariology, Umeå University, SE-901 87 Umeå, Sweden
Abstract
ABSTRACT
Actinomyces
spp. exhibit type 1 fimbria-mediated adhesion to salivary acidic proline-rich proteins (PRPs) and statherin ligands.
Actinomyces
spp. with different animal and tissue origins belong to three major adhesion types as relates to ligand specificity and type 1 fimbria genes. (i) In preferential acidic-PRP binding, strains of
Actinomyces naeslundii
genospecies 1 and 2 from human and monkey mouths displayed at least three ligand specificities characterized by preferential acidic-PRP binding. Slot blot DNA hybridization showed seven highly conserved type 1 fimbria genes (
orf1
- to -
6
and
fimP
) in genospecies 1 and 2 strains, except that
orf5
and
orf3
were divergent in genospecies 1. (ii) In preferential statherin binding, oral
Actinomyces viscosus
strains of rat and hamster origin (and strain 19246 from a human case of actinomycosis) bound statherin preferentially. DNA hybridization and characterization of the type 1 fimbria genes from strain 19246 revealed a homologous gene cluster of four open reading frames (
orfA
to -
C
and
fimP
). Bioinformatics suggested sortase (
orfB
,
orf4
, and part of
orf5
), prepilin peptidase (
orfC
and
orf6
), fimbria subunit (
fimP
), and usher- and autotransporter-like (
orfA
and
orf1
to -
3
) functions. Those gene regions corresponding to
orf3
and
orf5
were divergent, those corresponding to
orf2
,
orf1
, and
fimP
were moderately conserved, and those corresponding to
orf4
and
orf6
were highly conserved. Restriction fragment length polymorphism analyses using a
fimP
probe separated human and monkey and rat and hamster strains into phylogenetically different groups. (iii) In statherin-specific binding, strains of
A. naeslundii
genospecies 1 from septic and other human infections displayed a low-avidity binding to statherin. Only the
orf4
and
orf6
gene regions were highly conserved. Finally, rat saliva devoid of statherin bound bacterial strains avidly irrespective of ligand specificity, and specific antisera detected either type 1, type 2, or both types of fimbria on the investigated
Actinomyces
strains.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
49 articles.
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