Periodic phenomena in Proteus mirabilis swarm colony development.

摘要: Proteus mirabilis colonies exhibit striking geometric regularity. Basic microbiological methods and imaging techniques were used to measure periodic macroscopic events in swarm colony morphogenesis. We distinguished three initial phases (lag phase, first swarming consolidation phase) followed by repeating cycles of subsequent plus phases. Each terrace corresponds one swarming-plus-consolidation cycle. The duration the lag phase was dependent upon inoculation density a way that indicated operation both cooperative inhibitory multicellular effects. On our standard medium, second displayed structure form internal waves visible with reflected dark-field illumination. These resulted from organization migrating bacteria into successively thicker cohorts swarmer cells. Bacterial growth motility independently modified altering composition medium. By varying glucose concentration substrate, it possible alter biomass production without greatly affecting kinetics surface area expansion. agar bacterial unaffected but expansion dynamics significantly altered. Higher concentrations led slower, shorter longer Thus, restricted higher overall timing remained constant. None variety factors which had significant effects on altered terracing frequencies at 32 degrees C, length cycle affected temperature medium enrichment. Some clinical isolates differences C. Our results defined number readily quantifiable parameters development. data showed no connection between nutrient (glucose) depletion onset different Several observations point density-dependent thresholds controlling transitions distinct