TGFB1 and infection: To investigate a potential link between insulin signaling and TGF-β signaling in response to parasitic nematode infection, we used qRT-PCR and gene-specific primers to determine the transcript levels of dilp3, dilp6, and transcription factor fOXO in daw and dpp mutant larvae 24 h after infection with H. bacteriophora axenic or symbiotic nematodes.