The haemoglobins and respiratory enzymes in the ventral papillae of Notocotylus triserialis Diesing 1839 (Digenea: Notocotylidae)

Abstract

Ventral papillae of Notocotylus triserialis contain pyriform cells filled with mitochondria. To investigate the possible respiratory function of the papillae, N. triserialis was examined histochemically for numerous respiratory enzymes. α-Glycerophosphate, succinate, glutamate, lactate, and glucose-6-phosphate dehydrogenases and cytochrome oxidase were identified within the pyriform cells of the ventral papillae and lateral margins of the worm.Living N. triserialis are red, particularly the ventral papillae and lateral margins of the worms. Using spectroscopy, this pigment was identified as a true oxyhaemoglobin, with the α and β peaks at 570–580 and 530–540 nm, respectively, corresponding closely with those of its experimentally infected chicken host haemoglobin. Polyacrylamide gel electrophoresis showed three, possibly four, haemoglobins in N. triserialis, distinct from the two chicken haemoglobins. During in vitro experiments the bright red colour of the worms turned to a dull grey–blue when worms were deprived of oxygen and the red colour returned upon addition of oxygen to the culture medium. This suggested that the haemoglobins of N. triserialis had the ability to deoxygenate and reoxygenate in vitro.