Sequence Similarity-Based Proteomics in Insects:  Characterization of the Larvae Venom of the Brazilian Moth <i>Cerodirphia </i><i>s</i><i>peciosa</i>

Using a combination of tandem mass spectrometric sequencing and sequence similarity searches, we characterized the larvae venom of the moth <i>Cerodirphia speciosa</i>, which belongs to the <i>Saturniidae</i> family of the <i>Lepidoptera</i> order. Despite the paucity of available database sequence resources, the approach enabled us to identify 48 out of 58 attempted spots on its two-dimensional gel electrophoresis map, which represented 37 unique proteins, whereas it was only possible to identify 13 proteins by conventional non-error tolerant database searching methods. The majority of cross-species hits were made to proteins from the phylogenetically related <i>Lepidoptera</i> organism, the silk worm <i>Bombyx mori</i>. The protein composition of the venom suggested that envenoming by <i>C. speciosa</i> toxins might proceed through the contact with its hemolymph, similarly to another toxic <i>Lepidoptera</i> organism, <i>Lonomia obliqua.</i> Keywords: MS BLAST • homology search • insect proteomics • tandem mass spectrometry • insect venom