Seminar über aktuelle Fragen zur Dynamik komplexer Fluide: Formation of microdroplets around bacterial aggregates and cell survival on drying surfaces
Dec 13, 2018
10:30 - 11:30
Dr. Nadav Kashtan
The Hebrew University of Jerusalem, Israel
Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
While water is essential for life, a large share of bacterial life on earth is found on surfaces that are subjected to frequent drying events. Little is known about the surrounding microscale hydration conditions of different cell organizations (e.g. solitary and aggregated bacteria) on a drying surface, and how these conditions affects survival. One of the main research focuses of our lab is the life of bacteria on plant leaf surfaces. We recently revealed that microscopic droplets are formed around bacterial aggregates on a macroscopically dry surface at least partially due to deliquescence of salts. Deliquescent compounds are common on leaves (e.g. from aerosols) and were suggested to form thin liquid films and microdroplets during daytime as a result of the moderate relative humidity (RH) on the leaf surface. Notably, in our experiments, droplet size correlated with aggregate size, and cell survival was higher within larger droplets. We argue that bacteria can control their fate, at least to some degree, by modulating their self-organization on the surface, which in turn affect their microscale hydration conditions and consequently impact survival. Similar results were obtained with two different strains, Pseudomonas putida and P. fluorescens, suggesting this is not a species-specific phenomenon. The formation and retention of microdroplets around aggregates are likely central features of the leaf surface as a microbial habitat and key for bacterial survival on plant leaf surfaces.