Antibacterial peptides in hemocytes and hematopoietic tissue from freshwater crayfish Pacifastacus leniusculus: Characterization and expression pattern

• DOI: 10.1016/j.dci.2006.08.002
• Publication Date: 2006-10-03T12:04:53Z
• Authors: Pikul Jiravanichp...; So Young Lee; Young-A Kim; Tove Andrén; Irene Söderhäll
• Keywords: Lipopolysaccharides; 0301 basic medicine; DNA, Complementary; Hemocytes; Base Sequence; Gene Expression Profiling; Hematopoietic System; Molecular Sequence Data; Hepatopancreas; Astacoidea; Microbial Sensitivity Tests; Chromatography, Ion Exchange; Gram-Positive Bacteria; 03 medical and health sciences; Hemolymph; Gram-Negative Bacteria; Bacillus megaterium; Escherichia coli; Animals; Amino Acid Sequence; Cloning, Molecular; Antimicrobial Cationic Peptides

A 14 amino acid residues proline/arginine-rich antibacterial peptide designated as astacidin 2 was purified and characterized from hemocytes of the freshwater crayfish, Pacifastacus leniusculus. Astacidin 2 has a broad range of antibacterial activity against both Gram-positive and Gram-negative bacteria. The primary sequence of astacidin 2 is RPRPNYRPRPIYRP with an amidated C-terminal and the molecular mass is 1838Da determined by mass spectrometry. Furthermore, the cDNA of three different crustin antibacterial homologs were isolated from a crayfish hemocyte EST library. RT-PCR was used to analyze the expression of the genes coding for astacidin 2 and P. leniusculus crustins (Plcrustin) 1-3 after bacterial challenge. The expression of Plcrustin1 was upregulated in both hemocytes and hematopoietic tissue after challenge with Gram-negative Escherichia coli or Acinetobacter ssp. non pathogenic bacteria as well as by a Gram negative crayfish pathogenic bacterium (Aeromonas hydrophila). The PlCrustin3 transcript was only upregulated after inoculation with the non-pathogenic Acinetobacter ssp. while there was no change in expression of Plcrustin2 or astacidin 2 following a bacterial challenge.