Cellular microbiology and molecular ecology of Legionella–amoeba interaction

University of Louisville
Virulence (Impact Factor: 4.22). 03/2013; 4(4). DOI: 10.4161/viru.24290
Source: PubMed


Legionella pneumophila is an aquatic organism that interacts with amoebae and ciliated protozoa as the natural hosts, and this interaction plays a central role in bacterial ecology and infectivity. Upon transmission to humans, L. pneumophila infect and replicate within alveolar macrophages causing pneumonia. Intracellular proliferation of L. pneumophila within the two evolutionarily distant hosts is facilitated by bacterial exploitation of evolutionarily conserved host processes that are targeted by bacterial protein effectors injected into the host cell by the Dot/Icm type VIB translocation system. Although cysteine is semi-essential for humans and essential for amoeba, it is a metabolically favorable source of carbon and energy generation by L. pneumophila. To counteract host limitation of cysteine, L. pneumophila utilizes the AnkB Dot/Icm-translocated F-box effector to promote host proteasomal degradation of polyubiquitinated proteins within amoebae and human cells. Evidence indicates ankB and other Dot/Icm-translocated effector genes have been acquired through inter-kingdom horizontal gene transfer.

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Available from: Ashley Richards, May 02, 2014
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    • "They offer a cozy niche, protecting bacteria from environmental stresses such as biocides, antibiotics, acid, or osmotic stress ,and play also a role in the spread of the pathogen in anthropogenic aquatic systems (Declerck et al. 2007; Greub and Raoult 2004; Newton et al. 2010). Upon unfavorable conditions, FLA differentiate into cysts that are highly resistant at dormant stage, wherein L. pneumophila may be able to survive (Declerck et al. 2005, 2010; Richards et al. 2013). With favorable conditions, cysts may eventually excyst and thereby release the pathogen. "
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