Fig. 2

Immunohistochemical detection of acidic alpha-keratin (AE1 positive) (a, c, e-j, l) and basic alpha-keratin (AE3 positive) (b, d, k) in normal tissues from loggerhead sea turtles (Caretta caretta). a Epidermis showing intense immunoreactivity in the basal and suprabasal cells. Bar = 70 μm. b Epidermis; note that all layers except the cornified layer were immunolabelled, but the most intense immunoreactivity was observed in some suprabasal cells (arrows). Bar = 70 μm. c Oesophageal epithelium showing intense immunoreactivity in the basal and suprabasal cells. Bar = 70 μm. d Oesophageal epithelium showing immunoreactivity in all layers of the epithelium (except in the cornified layer) but more intense in some suprabasal cells (bold arrows); note also the weak immunoreactivity in the vascular endothelium (thin arrow). Bar = 70 μm. e Gastric mucosa showing intense immunoreactivity in many of the lining epithelial cells. Bar = 140 μm. f Small intestine epithelium showing intense immunoreactivity. Bar = 140 μm. g Liver; note the moderate immunoreactivity in the hepatocytes (thin arrow) and the intense immunoreactivity in a biliary duct (bold arrow). Bar = 35 μm. h Tracheal epithelium showing intense immunoreactivity. Bar = 70 μm. i Lung; intense immunoreactivity in the faveolar epithelium (thin arrows) and in the epithelium lining the bundles of smooth muscle (bold arrow). Bar = 240 μm. j Kidney; immunoreactivity was detected in the parietal layer of Bowman’s capsule (thin arrow), distal tubules (bold arrows), and collecting ducts (*). Bar = 140 μm. k Kidney; immunoreactivity was weak in the parietal layer of Bowman’s capsule (thin arrow) and intense in the distal tubules. Bar = 70 μm. l Salt gland; intense immunoreactivity in the epithelial cells of a central duct (*) and weak immunoreactivity in adjacent secretory acini. Bar = 140 μm. Dako EnVision+ System, Harris haematoxylin counterstain