The environmental bacterium Legionella pneumophila employs a Type IV secretion system (T4SS) to replicate in amoebae and macrophages in a unique ‘Legionella-containing vacuole’ (LCV), thereby causing Legionnaires' disease. The opportunistic pathogen responds to stress by (reversibly) forming ‘viable but non-culturable’ (VBNC) cells, which are metabolically active but non-culturable under standard conditions. In this study, we reveal that heat-induced VBNC L. pneumophila lack a functional T4SS, do not form LCVs, and cannot be resuscitated by phagocytes.

Acanthamoeba isolated from the extreme environments of the Puna salt plains in Argentina contain unique intracellular microbial communities that are distinct from those found in the surrounding environments. The number of shared taxa amongst intracellular amoebae across all sites was greater than the number of shared taxa between the amoebae and their respective environments.

This paper introduces the assembly graph as an integrative lens to unify ecological assembly theories across dynamical, informational, and probabilistic approaches. In addition to theory, it also presents strategies to empirically decompose and measure these graphs, bridging theoretical and empirical work toward predictive ecological assembly.