Das Schüttelverfahren als Methode für Zellwanduntersuchungen bei Pseudomonas aeruginosa. III. Mitteilung: Elektronenmikroskopisch nachweisbare Oberflächenänderungen

: A thermovariable inhibition of agglutination (EA) was demonstrated in two randomly chosen strains of Pseudomonas aeruginosa (table 1, article I). The temperature range from the loss of agglutinability to its recovery was as described in previous articles (II). The agglutination patterns were similar to those of the O-group-type strains 1 and 4, indicating that the IA is a widespread property among Pseudomonas aeruginosa strains. Shaking at moderate intensities for 20-60 hours restored the thermosensitive agglutinability (Table 2, article I), and the times necessary for restoration were somewhate dependent on the specific culture media and the strains used (table3, article I). After restoration of agglutinability the bacteria had maintained their capability to form stable suspensions in physiological saline solution (table 2, article I). Another treatment at elevated temperature did not result in an IA (table 5c, article I). During the shaking the pelleted bacteria did no longer exhibit their normal slimy stickiness, similar to what has been observed after treatment with hyaluronidase (17). When the shaking was continued after restoration of agglutinability a special serological phenomenon ("Rauh-Phanomen," cf. table 5b in article I) was noted. Suspension of the bacteria in physiological saline for 7 days did not result in the recovery from the thermovariable IA (table 4, article 1). The secondary forms of the agglutinates were similar to those of Enterobacteriaceae, the typical primary form of the agglutination into slimy networks and spheres was not observed upon the restoration of agglutinability. The hypothesis that loosely bound surface components are responsible for the thermovariable IA was examined by chemical analyses of the fractionated supernatants obtained during the shaking treatments. The first supernatant fractions obtained after relatively brief shaking periods exhibited a high viscosity, in contrast to the low viscosity of supernatants harvested later. Total acetone-precipitable material from the supernatants contained lipids, proteins and carbohydrates, however, at different ratios (tables 1, 2, 3, article II). The amounts of lipids recovered from the supernatants were similar in all fractions during the shaking treatment, whereas protein-carbohydrate complex material was maximal in the first fractions and significantly decreased in fractions harvested later (table 1 and 2, article II). The data indicated, that the restored agglutinability at elevated temperatures and the maintained suspensibility in physiological saline was due to the removal of a limited amount of material from the most superficial layer of the bacterial wall; however in the continuous presence of the cell membrane and perhaps also of the internal cell wall layers (see also 8). This concept was examined by electron microscopy. The morphology of the native bacteria is illustrated in figures 1-3 (article III)...