Cysteine-rich antimicrobial peptides of the cattle tick Boophilus microplus: isolation, structural characterization and tissue expression profile

• Published in: Developmental and comparative immunology Vol. 28; no. 3; pp. 191 - 200
• Main Authors: Fogaça, Andréa C, Lorenzini, Daniel M, Kaku, Luciana M, Esteves, Eliane, Bulet, Philippe, Daffre, Sirlei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.03.2004; Elsevier
• Subjects: Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - isolation & purification; Antimicrobial Cationic Peptides - pharmacology; Antimicrobial peptide; Arachnid, tick; Arthropod; Boophilus microplus; Cattle - parasitology; Chromatography, High Pressure Liquid; Cysteine-rich; Defensin; DNA, Complementary - chemistry; DNA, Complementary - genetics; Fat Body - chemistry; Female; Gene Expression; Hemocytes - chemistry; Hemolymph - chemistry; Immune system; Ixodidae - genetics; Life Sciences; Microbial Sensitivity Tests; Micrococcus luteus - drug effects; Molecular Sequence Data; Ovary - chemistry; Polymerase Chain Reaction; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Cysteine-rich; HCl, hydrochloric acid; BMCFH, antimicrobial fraction from Boophilus microplus cell-free hemolymph; MIC, minimum inhibitory concentration; Tris, 2-amino-2-hydroxymethylpropane 1,3-diol; Arachnid, tick; PBS, phosphate-buffer saline; BMH, antimicrobial fraction from B. microplus hemocytes; RP-HPLC, reverse phase-high performance liquid chromatography; Arthropod; AMPs, antimicrobial peptides; TFA, trifluoracetic acid; PMA, phorbol-12-miristate 13-acetate; DTT, dithiothreitol; MALDI-TOF-MS, matrix assisted laser desorption/ionization-time-of-flight-mass spectrometry; ACN, acetonitrile; LPS, lipopolysacharide; EDTA, ethylene diamine tetracetic acid; RACE, rapid amplification of cDNA ends; Defensin; ESI-MS, electrospray ionization-mass spectrometry; Antimicrobial peptide; Immune system; RT-PCR, reverse transcription-polymerase chain reaction
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2003.08.001

Antimicrobial peptides (AMPs) are components of the immune system of both vertebrate and invertebrate animals. This study describes the isolation, primary structure, cDNA cloning, and tissue expression profile of two cysteine-rich AMPs from the hemolymph of the cattle tick Boophilus microplus. A 10,204 Da polypeptide, with six cysteine residues and no sequence similarity to any known molecule, was isolated from the cell-free hemolymph. Because of its sequence originality, this peptide was named microplusin. The second AMP was isolated from the hemocytes of B. microplus. This peptide, with a molecular mass of 4285 Da and six cysteines, is a defensin with similarity to the insect defensin family members. The cDNA cloning established that microplusin is synthesized as a prepeptide while the tick defensin is synthesized as a prepromolecule. Interestingly, despite the fact that microplusin and defensin have been isolated from different compartments, their gene expression was found to have similar tissue distribution.