Fig. 8

The C. daubneyi gut is uniquely adapted for absorption. A C. daubneyi peptidases bearing an N-terminal signal peptide for secretion via the classical ER/Golgi pathway represent 22 peptidase families but are dominated by the C1A papain-like cysteine peptidases and A1A pepsin-like aspartic peptidases. Total TPM values [23] for each peptidase family were represented as a heat map (with a blue to red scale depicting low to high levels of expression, respectively) to visualise relative expression across the intra-mammalian life-cycle stages of C. daubneyi. NEJ, newly excysted juvenile; Im, immature intestinal flukes; NM, newly-migrated flukes; Ad, adult flukes. B Transmission electron micrograph of secretory cells comprising the gastrodermis in adult C. daubneyi. The elongated cells feature centrally situated, spheroidal euchromatic nuclei (N), each with a large nucleolus (Nu). The lateral plasma membranes are difficult to distinguish amongst elaborate infolds of the basal membranes (Bm), which reach to the apical cytoplasm. Granular endoplasmic reticulum (Ger) together with free ribosomes (R) predominate in the basal and perinuclear cytoplasm, whilst Golgi bodies (Go), each with dense secretory vesicles associated with the maturing face, occur frequently in the apical cytoplasm. These secretory vesicles form larger spherical to elongate secretory bodies towards the cell apex (S). Small mitochondria (M) of moderate electron density are numerous but inconspicuous. The apex of each cell is highly elaborated by numerous, long, densely packed and sometimes branching microvilli (Mv). Adjacent microvilli are sometimes connected by fine fibrous bridges (arrowed) emanating from the glycocalyx