Fig. 5

Distribution of GH5_5 signal on algae and dislodged Orciraptor cells and occurrence of GH5_5-positive granules over Orciraptor’s life history. A Optical cross section of an empty Actinotaenium cell with clear GH5_5 signal (pAb) at the margin of the hole (CFW stained cellulose in the algal wall). B C-shaped perforation with attached lid (in top-view, visualised by CFW fluorescence) and pronounced anti-GH5_5 signal (pAb) at the margins; Z-projection. C Attacking Orciraptor cell (experimentally dislodged from the alga, 1 h a.a.a.) without GH5_5 signal at the lysopodium. D Actinotaenium cell which has been experimentally freed from attacking Orciraptor cell displays a strong, ring-like GH5_5 signal (in cross section) at its surface. E Attacking Orciraptor cell with numerous GH5_5-positive granules in the cytoplasm; fluorescence micrograph is a Z-projection. F Attacking Orciraptor cell without GH5_5-positive granules of high intensity. G Percentage of Orciraptor cells with GH5_5-positive granules in the cytoplasm at five different time points (stages) during the feeding act: (1) free flagellates before feeding; (2) attached cell without GH5_5 signal at contact zone, 30 min a.a.a.; (3) attached cell with GH5_5 signal at contact zone but no visible cell wall alterations, 1 h a.a.a.; (4) attached cell with GH5_5 signal at contact zone and clear signs of cell wall lysis, 2 h a.a.a.; (5) Orciraptor with invading pseudopodia, 4 h a.a.a. (25 cells per stage analysed). Fluorescence micrographs in A, C, D and F represent single focal planes, those in B and E are Z-projections. All images except A (confocal laser scanning microscopy) were captured by widefield microscopy. Scale bars = 5 μm