The haemoglobins of Nippostrongylus muris (Yokagawa) and Strongylus spp

From time to time, in connexion with work on the metabolism of parasitic nemaodes, attention has been drawn to the presence of haemoglobin in a number of species. Aducco (1889) observed that the red colour of Dioctophyme renale is due to a pigment resembling vertebrate haemoglobin. More recently haemoglobin has been recorded in Ascaris lumbricoides and Parascaris equorum (Keilin 1925), in Nematodirus, Ostertagia and other Trichostrongylidae of sheep (Davey 1938) and in Camallanus (Wharton 1938). Among tissue parasites the pigment was demonstrated y Stannard, McCoy & Latchford (1938) in Trichinella larvae and by v. Brand (1937) in a larval Eustrongylides from the mesentery of Fundulus. The presence of haemoglobins in parasitic worms has been suggested as evidence that they were essential to supply oxygen to the oxidative systems (Davey 1938; Brand 1938). But not all authors presented evidence that the haemoglobins they observed were different from the haemoglobin of the host. Keilin (1925), however, observed that Ascaris lumbricoides contains two haemoglobins which could be distinguished spectroscopically from each other and from the host haemo­globin. These pigments were re-examined by Davenport (1949) and were found to have extremely high oxygen affinities, the consequence of a very low deoxygenation velocity. The oxygen equilibrium relations of the haemoglobins could not be determined directly but it was shown that Ascarisis capable of bringing about deoxygenation of the body-wall haemoglobin when kept under anaerobic con­ditions. Similarly Aducco (1889) observed that the haemoglobin of Dioctophyme is extremely resistant to deoxygenation in vacuo.