UBE2D2 and infection: Differential expression in resistant snail haemocytes of the serine protease elastase 2 which degrades extracellular matrix molecules and can mediate bacterial killing [34] and of ubiquitin conjugating enzyme E2D 2 which marks misfolded/damaged proteins for degradation by the 26S proteasome [35] is indicative of increased proteolysis in the face of infection and parasite induced stress.