Bacterial survival at solid-air interfaces: from individual response to population ecology

Acclimation and flexible response mechanisms are ancient survival modes allowing prokaryotic cells to conquer diverse habitats and maintain viability in nature. Evidently, lack of water significantly impacts cellular response making it vital for individual cells to benefit from population support and access survival means available beyond the cell boundaries. Microscopy of dried bacterial cells at solid-air interfaces suggested that cell membrane breakdown didn’t occur for months. Viable counts for Gram-positive Arthrobacter spp. and Gram-negative Pseudomonas stutzeri were significantly higher for larger population density during prolonged periods of desiccation and nutrient starvation. Presence of homogenized cells extended short-term survival of Arthrobacter spp. cells, while heat-killed cells significantly extended viability of all populations. It appeared that huddled zombielike cells allow preservation and recycling of essential survival components within a population. Understanding population-mediated survival at solid-air interfaces is key for monitoring and controlling bacteria including in deep geological repositories for nuclear waste management.