The planarian microbiome in response to external stressors

Abstract

Many animals live in close association with complex microbial communities. The so-called microbiomes include bacteria, fungi and viruses and are believed to have a beneficial effect on the hosts physiology. An altered microbial composition in humans is associated with adverse health outcomes such as diabetes, inflammatory bowel diseases and allergies. Also invertebrates, such as fruitflies and earth worms, have associated bacteria that are linked with beneficial traits in fitness, immune responses and metabolic processes. Recently a functional link between endogenous bacteria and the planarian physiology and regeneration process was demonstrated. We further investigated the planarian microbiome and its response to external stressors. Bacteria were present at the epidermis and in the gut of the worms. Alterations in Schmidtea mediterranea’s bacterial communities, as a response to environmental changes, were identified by a combination of ARISA fingerprinting and 16S rRNA sequencing. Of the studied compounds (Cd, MMS, AgNPs, …) and other external changes such as different food, silver nanoparticles had the highest impact on planarian microbiomes. In addition, microbiomes were studied in different phases of the regeneration process.