Sequential changes in dipterose activity with the developmental stage of the melon fly.

Melon fly eggs, larvae, or pupae were homogenized with four volumes of PBS. The homogenates were then centrifuged at 20,400×g for 30 min at 4°C and the sugar content of the supernatants were measured using the phenol-H₂SO₄ method. RAW264 cells were incubated with these diluted supernatants for 20 h and the nitrite levels in the culture medium were measured by Griess assay.