Browsing by Author "Schumann, Peter"

A novel myxobacterium, MCy1366(T) (An 733), was isolated in 1981 from a soil sample collected from a region near Tokyo, Japan. It displayed general myxobacterial features like Gram-negative-staining, rod-shaped vegetative cells, gliding on solid surfaces, microbial lytic activity, fruiting-body-like aggregates and myxospore-like structures. The strain was mesophilic, aerobic and showed a chemoheterotrophic mode of nutrition. It was resistant to many antibiotics such as cephalosporin C, kanamycin, gentamicin, hygromycin B, polymyxin and bacitracin, and the key fatty acids of whole cell hydrolysates were iso-C-15:0, iso-C-17:0 and iso-C-17:0 2-OH. The genomic DNA G+C content of the novel strain was 65.6 mol%. The 16S rRNA gene sequence showed highest similarity (97.60%) to 'Stigmatella koreensis' strain KYC-1019 (GenBank accession no. EF112185). Phylogenetic analysis based on 16S rRNA gene sequences and MALDI-TOF MS data revealed a novel branch in the family Myxococcaceae. DNA DNA hybridization showed only 28% relatedness between the novel strain and the closest recognized species, Corallococcus exiguus DSM 14696(T) (97% 16S rRNA gene sequence similarity). A recent isolate from a soil sample collected in Switzerland, MCy10622, displayed 99.9% 16S rRNA gene sequence similarity with strain MCy1366(T) and showed almost the same characteristics. Since some morphological features like fruiting-body-like aggregates were barely reproducible in the type strain, the newly isolated strain, MCy10622, was also intensively studied. On the basis of a comprehensive taxonomic study, we propose a novel genus and species, Aggregicoccus edonensis gen. nov., sp. nov., for strains MCy1366(T) and MCy10622. The type strain of the type species is MCy1366(T) (=DSM 27872(T)=NCCB 100468(T)).

von See C, Rucker M, Koch A, Kokemueller H, Schumann P, Ziebolz D, Gellrich N-C. The influence of pressure changes on endodontically treated teeth during simulated dives. International Endodontic Journal, 45, 57-62, 2012. Aim To measure and evaluate pressure changes in the pulp chambers of extracted teeth exposed to hyperbaric conditions during root canal treatment. Methodology A pressure sensor was inserted and sealed into the pulp chambers of extracted human molars (n = 6). The teeth were subjected to simulated dives to 4.5 bar in a diving chamber. During the simulated ascents and descents, the pressure within the pulp chamber was measured, and the difference between the pressure inside the pulp chamber and the pressure in the diving chamber was calculated. Each tooth underwent two dives with an intact pulp chamber, with a calcium hydroxide dressing, after root canal filling, and after adhesive sealing of the pulp chamber floor with a composite. Differences were analyzed statistically (P < 0.05) using one-way analysis of variance (anova). Results There were no significant pressure differences in teeth with an intact pulp chamber and teeth with a calcium hydroxide dressing. After root filling, however, the increase in pressure inside the pulp chamber was significantly lower (P < 0.05) than that in the diving chamber. After adhesive sealing of the pulp chamber floor with a composite, the pressure inside the pulp chamber was significantly lower (P < 0.05) than the pressure in the diving chamber. Conclusions In root canal treatment, canal orifices should be sealed with an adhesively bonded composite filling before a dive. The use of a calcium hydroxide dressing after root canal preparation does not disqualify patients from diving.