An immunohistological study of the localization of bacteria invading root pulpal walls of teeth with periapical lesions.

We immunohistologically examined the prevalence and localization of bacteria invading dentinal tubules of the roots of teeth with infected canals. Forty extracted teeth with apical lesions were selected and divided into two groups: a group of untreated teeth and a group of canal-enlarged teeth. The bacteria in the specimens were detected by Brown-Brenn stain and the labeled-streptavidin-biotin method with specific antisera for 16-bacteria. Seventy percent of the examined teeth showed bacteria invading the dentinal tubules of the roots. Fusobacterium nucleatum, Eubacterium alactolyticum, E. nodatum, Lactobacillus casei, and Peptostreptococcus micros were abundant. Even in the canal-enlarged group, invasion of bacteria was observed in 65% of teeth. This study revealed the actual condition of bacteria in infected root dentin and suggested that the canal-enlargement procedure could not completely remove all the bacteria in the infected dentinal tubules of the root.

Characterisation of Eubacterium cell wall: peptidoglycan structure determines arthritogenicity.

OBJECTIVE: To elucidate factors involved in the arthritogenicity of bacterial cell walls. METHODS: For characterisation of an arthritogenic Eubacterium aerofaciens cell wall, peptidoglycan-polysaccharide (PG-PS) polymers were isolated by removing cell wall associated proteins (CWPs), PG and PS moieties were separated, and an attempt was made to de-O-acetylate PG-PS. The cell wall of E limosum was used as a non-arthritogenic control. The chemical composition of these cell wall preparations was analysed by gas chromatography-mass spectrometry. Also, their ability to resist lysozyme degradation and to sustain experimental chronic arthritis was tested. RESULTS: The observations made with the cell wall of E aerofaciens, an anaerobic habitant of the human intestine, were compared with those reported from a pathogenic Streptococcus, showing that in both strains a complex consisting of PG-PS is required for the induction of chronic arthritis. The PS moiety most probably protects PG from enzyme degradation, allowing prolonged tissue persistence and leading to the chronic synovial inflammation. CWPs attached to PG-PS are not necessary for this function. O-Acetylation of PG, which is required for arthritogenicity of the streptococcal cell wall, seems not to be present in the arthritogenic E aerofaciens PG or only occurs to a small degree; attempts to de-O-acylate the E aerofaciens cell wall did not affect its arthritogenicity or lysozyme resistance. CONCLUSION: The results obtained indicate that the source of bacterial cell wall plays no part in the chemical or structural requirements for PG to induce chronic cell wall arthritis in the rats; the chemical structure of the PG moiety is decisive.

[About nannobacteria]. / O nannobakteriiakh.

Bacterial nanocells 0.2-0.3 micron in size and hundreds of a cubic micron in volume have been revealed in natural habitats and obtained in pure cultures. The taxonomic analysis of naturally occurring nanobacteria showed that they belong to the known taxa of the kingdom Eubacteria. The results of the cytological investigation of nanocells suggest that they are universally formed in response to stress impacts.

Anaerobic transformation of quercetin-3-glucoside by bacteria from the human intestinal tract.

From human feces two phenotypically different types of bacteria were isolated on quercetin-3-glucoside as carbon and energy source. Isolates of one type were identified as strains of Enterococcus casseliflavus. They utilized the sugar moiety of the glycoside, but did not degrade the aglycon further. The sugar moiety (4 mM) was fermented to 5.5 +/- 2.1 mM formate, 2.1 +/- 0.7 mM acetate, 1.6 +/- 0.3 mM l-lactate, and 1.3 +/- 0.4 mM ethanol. The second type of isolate was identified as Eubacterium ramulus. This organism was capable of degrading the aromatic ring system. Growing cultures of Eubacterium ramulus converted 5 mM quercetin-3-glucoside to 1.7 +/- 0.6 mM 3,4-dihydroxyphenylacetic acid, 7.6 +/- 1.0 mM acetate, and 4.0 +/- 0.4 mM butyrate. Molecular hydrogen, 3,4-dihydroxybenzaldehyde, and ethanol were detected in small amounts. Phloroglucinol was a transient intermediate in the breakdown of quercetin-3-glucoside. Eubacterium ramulus did not grow on the aglycon quercetin or the ring-fission intermediate phloroglucinol, but cleaved the flavonoid ring system when glucose was present as a cosubstrate. The most probable number of quercetin-3-glucoside-degrading bacteria determined in nine human fecal samples was 10(7)-10(9)/g dry mass. Isolates from these experiments were all identified as Eubacterium ramulus.

Regulation of the cellulolytic activity of Eubacterium cellulosolvens 5494: a review.

Eubacterium cellulosolvens 5494 is a cellulolytic gram positive bacterium isolated from the rumen. Substrate specific regulation has not been previously demonstrated in any members of this genera. However, we have recently found that E. cellulosolvens regulates some of its membrane proteins. Growth on different substrates, including cellulose and cellobiose, gave different SDS-PAGE profiles of proteins from the membrane fraction. Using scanning electron microscopy, we also found that growth of E. cellulosolvens on cellulose induces an ultrastructural complex that is not present when grown on any other substrate. Further study revealed that this ultrastructure was subsequently lost when an alternative substrate was made available to cellulose growing cells. We also found that cellulose, cellobiose, and maltose utilization are inhibited in the presence of a glucose analog, indicating glucose is the preferred substrate.

Eubacterium minutum sp. nov., isolated from human periodontal pockets.

We describe Eubacterium minutum sp. nov., which was isolated from human periodontal pockets. This new species was established on the basis of DNA-DNA hybridization data. The guanine-plus-cytosine content of its DNA is 38 to 40 mol%. The results of differential biochemical and enzymatic tests are described. The type strain of this species is strain M-6.

Clinical, and light and electron microscopical findings in sows with cystitis.

The clinical findings, and urinary and morphological changes in the urinary bladder were investigated in 25 sows with a urinary tract infection. Eubacterium suis was isolated from 12 of the sows but not from the other 13. The clinical signs did not always correlate with the morphological changes. The only clinical sign indicating the beginning of cystitis appeared to be a significant bacteriuria. Other urinary changes occurred later when the inflammatory processes were more severe. In contrast with cystitis due to other bacteria, infection with E suis frequently resulted in a macrohaematuria and urinary pH values above 8.0. However, the light and electron microscopical findings in the bladder mucosa were similar in the sows with and without cystitis due to E suis. The transformation of goblet cells and the development of mucin cysts were probably due to the local bladder defence mechanisms. More severe lesions were observed with E suis infections, which resulted in changes in the ureterovesical junctions and in ascending renal infection and uraemia.

Eubacterium yurii subspecies margaretiae is resistant to nonopsonic phagocytic ingestion.

We have previously shown that strains of Eubacterium yurii are hydrophobic, as compared with human polymorphonuclear leukocytes (PMNs), possibly because of a crystalline surface layer (S-layer) covering the cell envelope of this potential endo-perio pathogen. The aim of the present study was to investigate the phagocytic ingestion by PMNs of the three E. yurii subspecies, with special attention to bacterial surface structures and hydrophobicity. Type strains of subspp. margaretiae, yurii, and schtitka, together with three clinical isolates from necrotic root canals, were studied. All strains were hydrophobic when tested by a two-phase partition method. E. yurii subspp. margaretiae strains ATCC43715T, ES4C, and ES14B-8E were resistant to PMN ingestion in the absence of opsonins, whereas strains of the two other subspecies were readily ingested. The presence of a resistant strain (subsp. margaretiae ATCC43715T) did not inhibit the ingestion of a sensitive strain (subsp. schtitka ATCC43716T). Ingestion of E. yurii subsp. margaretiae strains required opsonization by normal human serum or specific antibodies. Electron microscopy revealed an S-layer in all strains and fimbria-like structures in the subspp. margaretiae and yurii strains. The antiserum prepared against the S-protein of E. yurii subsp. margaretiae ATCC43715T showed only slight cross-reactivity with other E. yurii strains and indicated the presence of strain-specific rather than species- or subspecies-specific antigens in the S-protein of E. yurii subsp. margaretiae ATCC43715T. The results suggest that the mere presence of the S-layer or fimbria-like structures cannot explain the susceptibility to ingestion by the PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Surface layers of Eubacterium yurii subsp. yurii and their possible role in test-tube brush formation and iron acquisition.

Eubacterium yurii subsp. yurii is an anaerobic, gram-positive rod. On isolation E. yurii forms cellular arrangements resembling test-tube brushes (TTB). Although TTB decreased in size and number on repeated laboratory subculture in enriched media, media poor in available iron enhanced formation of these. Plasmids were not demonstrated, even after chloramphenicol enhancement. To characterise the nature and possible physiological roles of the structures of the TTB, they were examined by transmission electronmicroscopy (TEM) with thin-section, negative-staining, shadow-casting, freeze-etching and freeze-fracturing techniques, and by scanning electronmicroscopy (SEM). Previous studies by phase-contrast microscopy revealed an amorphous core, the size of which varied in direct proportion to the number of associated bacterial cells. Thin sections of the TTB showed a gram-positive cell wall with additional surface layers. Negative staining, shadow casting and freeze etching revealed a surface layer comprising subunits in tetragonal array (P4 symmetry). Shadow casting showed also that the outermost layer of the cells was composed of fibrillar structures closely associated with but distinct from, the tetragonal layer. The fibrils extended from the cell surface in clumps or strands. The presence of these fibrils was confirmed by the freeze-fracture technique and SEM. Chemical analysis of the core material of the TTB showed it to be low in carbohydrate (0.06%) and protein (0.2%). Energy-dispersive X-ray spectrometry showed that the core was composed mostly of iron.(ABSTRACT TRUNCATED AT 250 WORDS)