PORPHYRIC PHOTOINSECTICIDES AGAINST PEST FLIES

PUJUL-LEREIS, L.M; MASSALDI, ANA; FILIBERTI, ADRIÁN; RABOSSI, ALEJANDRO; QUESADA ALLUÉ, LUIS ALBERTO

Mar del Plata, Buenos Aires

Congreso; XLVIII Reunión Anual SAIB; 2007

Soc. Argentina de Investigaciones Bioquímicas y Biología Molecular

PORPHYRIC PHOTOINSECTICIDES AGAINST PEST FLIES Pujol-Lereis, Luciana1,4; Ana Massaldi1,4; Adrián Filiberti3; Alejandro Rabossi1,2,4 and Luis A. Quesada-Allué1,2,4 1IIBBA-CONICET, 2QB-FCEyN-UBA, 3CIQUIBIC-UNC and 4Fund.Inst.Leloir, Bs.As, (1405). In recent years, attention has been focused on the photosensitizing properties of porphyrins since they produce reactive oxygen species (ROS) when illuminated. These have the ability to absorb in most of the wavelengths from UV to visible and to generate long live triplet states. To establish a proof of principle, we tested the larvicidal properties of Haematoporphyrin (HP) in immature stages of the Medfly, Ceratitis capitata and the Hornfly Haematobia irritans. A LD50 value of 0.14 mM was obtained for C.c, lower than for H.i. and lower than those obtained with the xanthene dye Phloxine B (PhB) too (LD50 of 0.5 mM). HP light-induced mortality was higher during the dispersal stage of the larvae (whereas larvae reared with PhB died during de pupal stage). We examined the presence of ROS in different tissues of larvae exposed to light, using a ROS detection test based on a fluorogenic marker (carboxy-DCFH). Only the midgut and the brain showed increased intensity of fluorescence, due to the oxidated state of the reagent. Total activity of catalase increased in HP treated larvae, whereas superoxide dismutase activity remained unchanged. We also found that larvae treated with HP presented increased levels of lipid peroxidation. Our results demonstrate that HP is a more effective larvicide than PhB and generates a lower lethal time.