About this Research Topic
Amoebae are eukaryotic microorganisms of great diversity. They do not form a single taxonomic group and are found among the protozoa, fungi, and algae. However, all amoebae are characterised by the amoeboid life style - the ability to change cell shape by extending and retracting pseudopods - and most amoebae can be considered as professional phagocytes, which feed on bacteria and other microorganisms by phagocytosis. But despite their impressive phagocytic activity, amoebae cannot degrade all microorganisms. Some resist the digestion and some even use amoebae as host cells for their own replication. Such microbial resistance is also observed in the complex relationship between phagocytes of the mammalian immune system and pathogenic bacteria. For example, Legionella pneumophila usually infects fresh-water amoebae, but can also use macrophages to further its own replication. This similarity has led to the concept of “amoebae as training grounds for (intracellular) pathogenic bacteria”, namely that pathogenic microorganisms can establish, select and “train” their virulence traits in free-living amoebae before being faced with phagocytic immune cells of animals. Recent studies using amoebae as host models for pathogens confirmed the broad plausibility of this concept. The most prominent amoebae used as host models are from the genera Acanthamoeba and Dictyostelium. Both have been demonstrated to be useful host cells for the study of the complex interactions with bacterial pathogens such as Legionella, Mycobacterium, Salmonella, Francisella, and others. Additionally, amoebae can also be used as model hosts for pathogenic fungi like Cryptococcus, Aspergillus, and Candida. These examples highlight the potential of amoebae as model hosts to study the interaction with a wide range of pathogenic microorganisms.
In this Frontiers Research Topic a large range of aspects of amoebae as host cells for pathogens will be covered. Which amoebae can be used as hosts? Which pathogens can be studied using amoebae? Which aspects of phagocytosis and killing by the amoebae are in common with mammalian phagocytes such as macrophages and neutrophils? Do pathogens distinguish between amoebae and phagocytes of the animal immune system? Which are the most evolutionary conserved mechanisms? Some of these questions will be answered in this Research Topic.
Keywords: amoebae, host-pathogen-interaction, evolution, phagocytes, immune system
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