The major outer sheath protein of Treponema denticola inhibits the binding step of collagen phagocytosis in fibroblasts

Bacterial infections contribfute to the chronicity of connective tissue lesions in part by perturbing extracellular matrix remodelling processes. We examined a novel mechanism by which the major outer sheath protein (Msp) of the spirochaete Treponema denticola disrupts matrix remodelling mediated by intracellular digestion of collagen. The initial collagen-binding step of phagocytosis was examined in human gingival fibroblasts and Rat-2 fibroblasts. Cells were pretreated with Msp or vehicle, and binding of collagen-coated beads was measured by flow cytometry. Exposure to Msp induced a dose- and time-dependent decrease in cells that bound collagen beads; the inhibition of binding was reversed by absorption with anti-Msp antibodies. Msp-treated fibroblasts remained viable but underwent actin reorganization, including the assembly of a dense meshwork of subcortical actin filaments. Shear force assays showed that Msp abrogated collagen-binding interactions in the minimal affinity range required for stable adhesion. Fluorescence microscopy and immunoblotting showed equivalent amounts of beta1 integrin associated with collagen beads bound to Msp- and vehicle-treated cells. Photobleaching experiments found a similar percentage mobile fraction of beta1 integrins recovered in bleached areas of the plasma membrane. In contrast, Msp-induced inhibition of collagen binding was reversed by beta1 integrin affinity-activating antibodies and by latrunculin B, which prevented subcortical actin assembly. We conclude that native Msp of T. denticola inhibits the binding step of collagen phagocytosis in fibroblasts by inducing subcortical actin filament assembly and restricting affinity modulation of beta1 integrins. We suggest that, like Msp, bacterial toxins that target the cytoskeleton may also perturb the signalling networks required for cellular engagement of matrix ligands.

Treponema socranskii, Treponema denticola, and Porphyromonas gingivalis are associated with severity of periodontal tissue destruction

BACKGROUND

The aim of the present study was to identify Treponema socranskii in addition to Treponema denticola and Porphyromonas gingivalis by polymerase chain reaction (PCR), and to clarify the relationship between the presence of these microorganisms and the severity of clinical periodontal parameters.

METHODS

Saliva and subgingival plaque collected from 123 subjects (38 aggressive periodontitis patients, 65 chronic periodontitis patients, 20 healthy patients) were subjected to PCR to detect the aforementioned 3 microorganisms.

RESULTS

Detection frequencies of T. socranskii, T. denticola, and P. gingivalis in plaque samples from aggressive periodontitis patients (71.1%, 73.7%, 84.2%, respectively) and chronic periodontitis patients (89.2%, 93.8%, 95.3%) were much higher than those from healthy subjects (30%, 5.0%, 10.0%). In aggressive and chronic periodontitis patients, these 3 species of bacteria were detected frequently at sites that showed deep periodontal pockets and severe attachment loss. The percentage of these bacteria-positive sites increased as the gingival index score of chronic periodontitis patients increased. T. socranskii was frequently detected together with T. denticola or P. gingivalis at the same sites, and coexistence of these microorganisms was frequently observed in deep periodontal pockets of aggressive periodontitis patients.

CONCLUSIONS

T. socranskii, T. denticola, and P. gingivalis were frequently detected in periodontitis patients by PCR. The prevalence of these 3 microorganisms was correlated with various clinical parameters. Taken together, our findings suggest that T. socranskii, T. denticola, and P. gingivalis are associated with the severity of periodontal tissue destruction.

Analysis of gene expression in Treponema denticola with differential display polymerase chain reaction

Treponema denticola is an oral spirochete associated with the periodontal diseases. A great deal of the molecular components of T. denticola will be learned soon since its genome sequence project is on the way. One of the most important works after genome sequence is to analyze the function of these genes and their regulation. However, like many other oral pathogens, there are currently a very limited number of molecular and genetic tools available to study gene expression in T. denticola. In this article, we describe a method of adapting differential display polymerase chain reaction (ddPCR) for use in the T. denticola system. To test for effectiveness of this protocol, we used three different temperature conditions, 4 degrees C, 25 degrees C and 42 degrees C, to test for differential gene expression. With various ddPCR conditions, we found a number of genes that were expressed differentially. Some of these differentially expressed genes were cloned and sequenced and found to be homologous with the known temperature-regulated genes, including HtrA. The study indicates that the ddPCR method can be effectively used in T. denticola for analyzing gene expression under various conditions.

Lymphocyte transformation in inbred guinea pigs infected with Treponema pallidum nichols

T lymphocytes were purified from peritoneal exudates from young male, inbred strain 2 guinea pigs infected with 8 X 10(7) Treponema pallidum Nichols and from control animals injected with normal rabbit testes extract. Groups of animals were sacrificed after 15, 30, 60, and 90 days of infection, and the cells were analyzed for their proliferative response to concanavalin A and phytohemagglutinin and to sonicated T. pallidum, Treponema phagedenis biotype Reiter, and normal rabbit testes extract. No significant differences were observed in the responses to mitogens. Cells from infected but not from control animals responded with significant proliferation to T. pallidum antigen, but neither infected nor control cells reacted to T. phagedenis Reiter antigen. Although cells from both infected and control animals responded to normal rabbit testes extract, this response in the infected animals was transient and much lower than the response to T. pallidum antigen.

Microtitration agglutination for detection of Treponema hyodysenteriae antibody

A microtitration agglutination test for the detection of Treponema hyodysenteriae antibody in swine and rabbit sera is described. The following methods provided the best test results: antigen produced from the spirochete after a culturing period of 36 to 44 h at 38 degrees C, washed antigen inactivated with 0.01% Merthiolate at 4 degrees C for 24 to 36 h, sera heated at 56 degrees C for 30 min, a diluent of phosphate-buffered saline (0.01 M, pH 7.2), and test results read macroscopically after 18 to 24 h of incubation at 38 degrees C. The test enabled detection of antibody against pathogenic T. hyodysenteriae with a high level of consistency and sensitivity. Sera against nonpathogenic T. hyodysenteriae produced low agglutinating titers (less than or equal to 1:8) when reacted against antigen from pathogenic isolates. Inactivated antigen remained stable for 7 to 10 days. Specificity of the reaction in the agglutination test was shown by absorption studies.

Accidental human infection in the laboratory with Nichols rabbit-adapted virulent strain of Treponema pallidum

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CLINICAL EVALUATION OF TYLOSIN AS A TREATMENT OF VIBRIONIC DYSENTERY IN SWINE

A 5 year history of swine dysentery and treatment has been described.In 1964, a severe outbreak diagnosed as Vibrionic dysentery in 166 litters farrowed from January - March caused a death loss of 30.3 per cent of the total number weaned. This outbreak was not checked with an organic arsenic, sodium arsanilate, which had previously been relatively effective.A subsequent farrow of 133 litters (June - August, 1964) was infected and again sodium arsanilate was ineffective. Microscopic examination of smears of representative fecal samples revealed the presence of a heavy concentration of vibrio-like organisms. Two test-barns, housing 140 and 172 pigs respectively, were treated with tylosin-tartrate, using one side of each barn as a control, while the other side was being treated. Subsequently, the control sides were treated. Both levels of tylosin used, 1 gm and 2 gm per U.S. gallon of water, resulted in the disappearance of fluid feces within 48 hours of treatment. Soft, granular feces were still present 6-9 days after the start of treatment at the 1 gm level, while in case of the 2 gm level of tylosin, all feces were normal on the third day after medication started. Microscopic examination of feces collected on the third day of treatment still revealed the presence of some vibrio-like organisms. However, these organisms could not be detected in examination of feces collected between 10 to 25 days after treatment. In this test there was no recurrence of dysentery.

Interspecific Transfer of the "Sex-Ratio" Agent of Drosophila willistoni in Drosophila bifasciata and Drosophila melanogaster

The maternally transmitted "sex-ratio" condition in several species of Drosophila appears to be due to infection by a microorganism of the genus Treponema. Drosophila bifasciata is an exception, since no microorganism has been found in the "sex-ratio" strains of this species. Normal D. bifasciata can be infected by injection of the hemolymph of a "sex-ratio" strain of D. willistoni containing treponemas. The progenies of the infected D. bifasciata, up to and including the F(4) and F(5) generations, have numerous treponemas in their hemolymph. Their progenies are, however, not unisexual, although both females and males are infected. The hemolymph of these D. bifasciata injected in D. melanogaster females causes typical "sex-ratio" symptoms in the progenies of the latter.