Two Novel Mosquitocidal Peptides Isolated from the Venom of the Bahia Scarlet Tarantula ().

Effective control of diseases transmitted by is primarily achieved through vector control by chemical insecticides. However, the emergence of insecticide resistance in undermines current control efforts. Arachnid venoms are rich in toxins with activity against dipteran insects and we therefore employed a panel of 41 spider and 9 scorpion venoms to screen for mosquitocidal toxins. Using an assay-guided fractionation approach, we isolated two peptides from the venom of the tarantula with activity against adult The isolated peptides were named U-TRTX-Lk1a and U-TRTX-Lk2a and comprised 41 and 49 residues with monoisotopic masses of 4687.02 Da and 5718.88 Da, respectively. U-TRTX-Lk1a exhibited an LD of 38.3 pmol/g when injected into and its modeled structure conformed to the inhibitor cystine knot motif. U-TRTX-Lk2a has an LD of 45.4 pmol/g against adult and its predicted structure conforms to the disulfide-directed β-hairpin motif. These spider-venom peptides represent potential leads for the development of novel control agents for .