Identification of a 95 kDa putative adhesin from Actinomyces serovar WVA963 strain PK1259 that is distinct from type 2 fimbrial subunits.
The species Actinomyces serovar WVA963 is among the 20 bacteria most frequently isolated from human subgingival plaque. The interactions of this species with streptococci are inhibited by lactose, a function associated with type 2 fimbrial surface structures in Actinomyces naeslundii. Type 1 fimbriae mediate binding of cells to salivary proline-rich proteins. Specific polyclonal antisera against type 1 and type 2 fimbriae of A. naeslundii T14V revealed both types of fimbriae on Actinomyces serovar WVA963 strain PK1259. To investigate the role of type 2 fimbriae of strain PK1259 in Actinomyces-Streptococcus lactose-inhibitable coaggregations, spontaneous coaggregation-defective (Cog-) mutants that failed to coaggregate with streptococci were isolated; three were chosen for study. All three mutant strains synthesized type 1 fimbriae and a 59 kDa protein; mutant strains PK2415 and PK3092 synthesized type 2 fimbriae and a 57 kDa protein. In contrast, the Cog- strain PK2407 did not agglutinate with anti-type 2 antibodies or show the 57 kDa band, suggesting that the 57 kDa protein was the type 2 fimbrial subunit. Polyclonal antiserum raised against the Actinomyces serovar WVA963 strain PK2399, an antibiotic-resistant derivative of wild-type PK1259, blocked coaggregation between this strain and streptococci. Anti-PK2399 serum absorbed with mutant strain PK3092 bearing type 2 fimbriae retained its blocking ability. Surface sonicates of the parent and mutant strains were adsorbed to streptococcal cells and to lactose-agarose beads. Lactose eluates from both the streptococcal cells and the affinity beads were characterized by SDS-PAGE and corresponding immunoblots using anti-PK2399 serum absorbed with Cog- mutant PK3092. These blots revealed a 95 kDa putative adhesin in the parent strain PK2399 that was absent in the Cog- mutant strain PK3092. These results suggest the presence of a putative 95 kDa actinomyces adhesin distinct from the 57 kDa type 2 fimbrial subunit and that this adhesin mediates lactose-inhibitable coaggregation with streptococci.
Klier
Christiane M
CM
Laboratory of Microbial Ecology, National Institute of Dental Research, National Institutes of Health,Bethesda, MD 20892,USA.
Kolenbrander
Paul E
PE
Laboratory of Microbial Ecology, National Institute of Dental Research, National Institutes of Health,Bethesda, MD 20892,USA.
Roble
Arlene G
AG
Laboratory of Microbial Ecology, National Institute of Dental Research, National Institutes of Health,Bethesda, MD 20892,USA.
Marco
Maria L
ML
Laboratory of Microbial Ecology, National Institute of Dental Research, National Institutes of Health,Bethesda, MD 20892,USA.
Cross
Sharon
S
Microbiology Research Group, School of Biological Sciences, Stopford Building, Manchester University,Oxford Road, Manchester M13 9PT,UK.
Handley
Pauline S
PS
Microbiology Research Group, School of Biological Sciences, Stopford Building, Manchester University,Oxford Road, Manchester M13 9PT,UK.
D000190:Actinomyces / Q000378:metabolism*; D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D010861:Fimbriae, Bacterial / Q000737:chemistry / Q000235:genetics; D006801:Humans; D009154:Mutation
D018829:Adhesins, Bacterial