Two separate species of lipopolysaccharide (LPS) from Bacteroides gingivalis 381 have been isolated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated not only the heterogeneity of each species, but also that they represented highand low-molecular-weight LPS entities. Although both contained the same
BALB/c mice were immunized with an invasive (A7A1-28) or noninvasive (381) Bacteroides gingivalis strain, Bacteroides intermedius, or Ringer solution. All immunized mice were subsequently challenged with the invasive B. gingivalis strain and examined for septicemia or secondary spread of the infection or both. Mice immunized with the invasive B. gingivalis strain localized the infection to the challenge site. Mice immunized with the noninvasive B. gingivalis strain, B. intermedius, or Ringer solution developed spreading infections. These data suggest that immunization with an invasive B. gingivalis strain can alter the course of subsequent infections. Anaerobic bacteria such as Bacteroides species are prevalent in infections characterized by suppuration and abscess formation (1). Bacteroides gingivalis is a gram-negative oral bacterium that has been associated with adult periodontal disease (14-17, 19, 22, 24) and abscesses of oral origin (2, 8, 20). Previous studies have demonstrated heterogeneity of virulence among different B. gingivalis isolates in mice (6, 10, 18), and guinea pigs (5, 6). Some strains produce a localized abscess at the injection site, while others spread to distant sites and may produce septicemia and death. Therefore, based on its pathogenesis in animal models, B. gingivalis can be classified as invasive or noninvasive. The role of prior immunization in modifying the response to experimental infection has been examined by using the murine model. For example, mice infected with Bacteroides fragilis can be protected from disease by immunization (11-13, 23). The present study was performed to determine whether immunization with B. gingivalis could protect mice from abscess formation or secondary spread of the infection or both after challenge with an invasive B. gingivalis isolate. An invasive and a noninvasive B. gingivalis strain were used in this study. B. gingivalis 381 (courtesy of S. S. Socransky, Forsyth Dental Center) was isolated from an adult with periodontitis. Previous studies in our laboratory have shown that this strain induces localized abscesses in mice and does not produce a secondary lesion (10). It is categorized as noninvasive. B. gingivalis A7A1-28, an invasive strain, was isolated in 1985 at the State University of New York at Buffalo from a 9-mm pocket in a 37-year-old male periodontitis patient with non-insulin-dependent diabetes mellitus. In mice, this B. gingivalis isolate produces ulcerated lesions distant from the injection site, septicemia, and often death (10). The pathogenic potential of this strain is similar to that described for strains W50 and W83 by Van Steenbergen et al. (18). Bacteroides intermedius ATCC 25261, obtained from the American Type Culture Collection, Rockville, Md., was used as a control. All bacteria were cultured on tryptic soy agar (Difco Laboratories, Detroit, Mich.) supplemented with 5% sheep blood (Crane Laboratories, Inc., Syracuse, N.Y.), 5 ,ug of hemin (Sigma Chemical Co., St. Louis, Mo.) per ml, 0.5 ,ug of menadione * Corresponding au...
The ultrastructures and surface protein profiles of aerobically cultured Actinobacillus actinomycetemcomitans (Haemophilus actinomycetemcomitans) differed from those of cells cultured anaerobically. Similar ultrastructural differences were also observed when aerobic and anaerobic cultures of a strain of Escherichia coli were compared. These results suggest that oxygen-related variations in the bacterial cell surface may play a role in the adaptation of oral bacteria to different host environments.Actinobacillus actinomycetemcomitans (Haemophilius actinomycetemcomitans) ( 13), a gram-negative, capnophilic, facultatively anaerobic coccobacillus, is a constituent of the normal oral flora which has been associated with several severe human infections, including abscesses, actinomycosis, meningitis, and endocarditis (20). In addition, a strong correlation has been established between this microorganism and specific forms of human periodontal disease (20,21).Many studies have examined the effect of environmental conditions on the composition of the bacterial cell surface, including factors such as nutrient limitation (8), growth phase (1,14), and the concentration of various ions (1, 8), and sugars (3). However, the effects of anaerobiosis on cell surface composition and structure have not been well characterized. Facultatively anaerobic bacteria may be able to adapt to conditions of varying oxygen tension within the host through oxygen-induced alterations of the cell surface. In the present study, the effect of anaerobiosis on the cell surface of A. actinomycetemcomitans was examined.A. actinomycetemcomitans 75 and 109, both serotype a oral isolates (21) exhibiting a rough colony morphology [T.
The family of type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions, where they appear to provide protective functions. To establish the size of the human gene family encoding these proteins, we isolated cosmid and lambda genomic clones. Restriction mapping, partial sequence analysis, and hybridization studies identified a total of seven distinct genes, six of which correspond to known genes and proteins. Sequence analysis showed that the seventh gene, CSTP2, is an apparent pseudogene carrying a nonsense mutation in exon 1 distinct from that in CSTP1. Southern blots of genomic DNA probed with gene-specific probes accounted for all but one or two sets of fragments containing exon 1, and one or two sets of fragments containing exon 3, indicating that the human type 2 cystatin gene family consists of eight or nine members. Southern blot analysis of large restriction fragments using these gene-specific probes indicates that all seven of the cloned type 2 cystatin genes are clustered at a single locus on human chromosome 20. This locus is no larger than about 910 kb, and possibly as small as 365 kb. We designate this as the CST locus and suggest a numbering system for the cystatin genes.
The effect of lipopolysaccharide preparations from Salmonella enteritidis, Bacteroides gingivalis, and Actinobacillus actinomycetemcomitans on human gingival fibroblasts was studied. Lipopolysaccharide from all sources inhibited fibroblast proliferation in the concentration range of 0.5 to 50 micrograms/ml, with the lipopolysaccharide from A. actinomycetemcomitans having the strongest inhibitory effect. Assessment of the effect of lipopolysaccharide on gingival fibroblast metabolism indicated both total protein and proteoglycan synthesis to be inhibited with increasing concentrations of lipopolysaccharide. As for the antiproliferative effect, lipopolysaccharide from A. actinomycetemcomitans had the greatest inhibitory effect on cell synthetic activity. This inhibitory effect was determined by pulse-chase experiments to be a true depression in synthesis. Furthermore, the effect was independent of lipopolysaccharide-induced changes in cell proliferation and prostaglandin synthesis. This study confirmed the toxic effect of lipopolysaccharide on fibroblasts and, in particular, indicated that various lipopolysaccharide preparations vary in their potency to influence cell proliferation and extracellular matrix synthesis.
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