Fig 4. Phylogenomic analysis of three proteases related to hemoglobin digestion in eight nematodes.

(a), H&E stained longitudinal section of the digestive tract from a female adult (on the upper left) shows the presence of red blood cells. The possible hemoglobin digestion pathway in the nematodes is illustrated on the right panel [65] with subfamily of enzymes (aspartic protease, cysteine protease and metalloprotease) related to hemoglobin and/or tissue digestion highlighted in yellow background. Specifically, the expanded subfamilies of enzymes from A. cantonensis are highlighted in red. Maximum likelihood phylogenies of necepsin-1 (b), Lgmn (c) and Nep-1(d) show expansion of these proteases in A. cantonensis, N. americanus and/or H. contortus, all of which are blood-feeding nematodes.