Authors

Discussion

Biofilms are defined as a structured community of microbial cells firmly attached to a surface and embedded in a matrix composed of Extracellular Polymeric Substances (EPSs). EPSs are composed by polysaccharides, nucleic acids, proteins, lipids and other biomolecules. This lifestyle allows cells to survive in hostile environments, but also to colonize new niches by dispersal of microorganisms from the microbial clusters. In this work, we demonstrated that the honeybee-infective trypanosomatid parasite Lotmaria passim promastigote forms are capable to secrete EPSs and differentiate into sessile biofilm colonies composed by surface-attached haptomonad parasite forms. This developmental differentiation is shown in experimental infections of honeybees and is also shown in vitro. Microscopic analysis showed that EPSs are structured in long fibers formed by monomeric structures of spherulites and extracellular vesicles over the surface of haptomonad cells. Proteomic comparison with dixenous trypanosomatid parasites showed that 58 out of 244 proteins are specific to L. passim EPSs with several being related with biofilm formation in prokaryotic organisms. Moreover, and in comparison to dixenous trypanosomatid parasites such as Trypanosoma cruzi or Leishmania major, we demonstrated that EPSs are necessary and partially sufficient to provide and increased resistance to osmotic and temperature stresses in L. passim. This results demonstrate that EPS and biofilm formation are necessary for survival, resilience and dispersal of monoxenous trypanosomatid parasites in nature.