Fogaça A C, da Silva P I, Miranda M T, Bianchi A G, Miranda A, Ribolla P E, Daffre S
Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, CEP 05508-900, São Paulo, Brazil.
J Biol Chem. 1999 Sep 3;274(36):25330-4. doi: 10.1074/jbc.274.36.25330.
Antifungal and antibacterial activities were detected in the hemolymph and gut contents of the cattle tick, Boophilus microplus. A peptide with antibacterial activity from the tick gut contents was purified to homogeneity by reversed-phase chromatography. The molecular mass of the purified peptide was 3,205.7 Da, measured by matrix-assisted laser desorption/ionization mass spectrometry. The amino acid sequence was obtained by Edman degradation and showed that the peptide was identical to a fragment of the bovine alpha-hemoglobin. A synthetic peptide based on the sequence obtained showed characterization data identical to those of the isolated material, confirming its structure. The synthetic peptide was active in micromolar concentrations against Gram-positive bacteria and fungi. These data led us to conclude that the antibacterial activity detected in tick gut contents is the result of enzymatic processing of a host protein, hemoglobin. This activity may be used by ticks as a defense against microorganisms.
