Figure 2.

Optimisation of absorption contrast. Coronal and sagittal virtual sections of adult medaka stained with PTA (a), I₂KI (b), EuCl₃ (c) and unstained control (d). Enlargements of boxed regions are shown. Note the superior absorption contrast of specimen stained with PTA. (a) PTA staining results in good differential absorption of all body regions and tissues, including tail musculature (red arrow heads). (b) I₂KI staining results in differential absorption in eye (1, red arrowhead). I₂KI precipitates result in strong signals in the head region, intestine and spine (1, 3, yellow arrowheads; 4, spine). Absorption in inner organs is weak with low tissue specificity (2, 3, red arrowheads). (c) EuCl₃ staining results in strong staining of bones (red arrowheads) and weak absorption in inner organs. Yellow arrowhead depicts morphological artefacts of the skull. Note weak absorption in soft tissue (2, yellow arrowhead). (d) In unstained adults, very weak absorption is visible in the eye (1) and gut (3, yellow arrowhead), whereas bones result in strong absorption (2, 4, red arrowheads). Scale bars: 6 mm.