Transmission electron micrograph showing laminin and circumsporozoite protein distribution in P. berghei oocysts 14 days post-infection. A) Oocyst on the edge of the midgut epithelium (12,000 ×; scale bar = 2 μm). B boxed area with solid line, C) boxed area with dotted line (40,000 ×; scale bar = 1 μm). The oocyst capsule appears darker than the layer of basal lamina coating it. Remnants of basal lamina are seen on the edge of the oocyst facing the haemocoel (B) and a thicker layer is seen adjacent to the basal labyrinth of the midgut epithelium (C) (diamond arrows). The majority of 30 nm gold particles indicating laminin labelling (1:800) (arrows) are found on the outer surface of the oocyst capsule. Note that some laminin labelling is also found in association with developing sporozoites The 10 nm gold particles correspond to circumsporozoite protein labelling (1:4000). BL = basal lamina, Cap = capsule, Sp = sporozoite.