![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
Previous Article | Next Article 
Infection and Immunity, October 1998, p. 4895-4902, Vol. 66, No. 10
Institute of
Dentistry,1
Department of Research
Laboratory,
Received 12 March 1998/Returned for modification 4 May
1998/Accepted 7 July 1998
Nonopsonic phagocytosis of Bacillus cereus by human
polymorphonuclear leukocytes (PMNs) with particular attention to
bacterial surface properties and structure was studied. Two reference
strains (ATCC 14579T and ATCC 4342) and two clinical
isolates (OH599 and OH600) from periodontal and endodontic infections
were assessed for adherence to matrix proteins, such as type I
collagen, fibronectin, laminin, and fibrinogen. One-day-old cultures of
strains OH599 and OH600 were readily ingested by PMNs in the absence of
opsonins, while cells from 6-day-old cultures were resistant. Both
young and old cultures of the reference strains of B. cereus were resistant to PMN ingestion. Preincubation of PMNs
with the phagocytosis-resistant strains of B. cereus did
not affect the phagocytosis of the sensitive strain. Negatively stained
cells of OH599 and OH600 studied by electron microscopy had a
crystalline protein layer on the cell surface. In thin-sectioned cells
of older cultures (3 to 6 days old), the S-layer was observed to peel
off from the cells. No S-layer was detected on the reference strains.
Extraction of cells with detergent followed by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis revealed a major 97-kDa
protein from the strains OH599 and OH600 but only a weak 97-kDa band
from the reference strain ATCC 4342. One-day-old cultures of the
clinical strains (hydrophobicity, 5.9 to 6.0%) showed strong binding
to type I collagen, laminin, and fibronectin. In contrast, reference
strains (hydrophobicity,
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Surface Structure, Hydrophobicity, Phagocytosis,
and Adherence to Matrix Proteins of Bacillus cereus Cells
with and without the Crystalline Surface Protein Layer
1.0 to 4.2%) as well as 6-day-old cultures
of clinical strains (hydrophobicity, 19.0 to 53.0%) bound in only low
numbers to the proteins. Gold-labelled biotinylated fibronectin was
localized on the S-layer on the cell surface as well as on fragments of
S-layer peeling off the cells of a 6-day-old culture of B. cereus OH599. Lactose, fibronectin, laminin, and antibodies against the S-protein reduced binding to laminin but not to
fibronectin. Heating the cells at 84°C totally abolished binding to
both proteins. Benzamidine, a noncompetitive serine protease inhibitor,
strongly inhibited binding to fibronectin whereas binding to laminin
was increased. Overall, the results indicate that changes in the
surface structure, evidently involving the S-layer, during growth of
the clinical strains of B. cereus cause a shift from
susceptibility to PMN ingestion and strong binding to matrix and
basement membrane proteins. Furthermore, it seems that binding to
laminin is mediated by the S-protein while binding to fibronectin is
dependent on active protease evidently attached to the S-layer.
*
Corresponding author. Mailing address: Institute of
Dentistry, P.B. 41, University of Helsinki, FIN 00014 University of
Helsinki, Helsinki, Finland. Phone: 358-9-19127354. Fax:
358-9-19127519. E-mail:
kotiranta{at}hammas.helsinki.fi.
Infection and Immunity, October 1998, p. 4895-4902, Vol. 66, No. 10
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|
