Figure 3

Micrographs depicting the association of Toxoplasma gondii with microplastics. Alcian blue, a stain that binds to exopolymer substances prevalent in biofilms, was used to visualize the association between the plastic surface and parasite oocysts. Polyester microfibers (A) and 100 μm blue polyethylene microbeads (D) that were not pre-conditioned in seawater demonstrate a lack of biofilm on the plastics prior to the experiments (no visible light blue matrix on their surface under brightfield illumination). Microfibers and microbeads following pre-conditioning and incubation with T. gondii were imaged under brightfield illumination (B and E, respectively) and a combination of brightfield illumination and UV epifluorescence that allows visualization of naturally autofluorescent T. gondii oocysts (C and F, respectively). Enlarged inset shows a T. gondii oocyst embedded in biofilm (blueish irregular matrix) on the fiber and bead surface. All scale bars are 20 μm.