Fish & Shellfish Immunology (2008) 25, 181-187
© 2008 The Author(s)

Isolation and characterisation of two antimicrobial peptides from haemocytes of the American lobster Homarus americanus

Andrea L. Battison ^a,*, Rachael Summerfield ^a, Aleksander Patrzykat ^b

^a Atlantic Veterinary College Lobster Science Centre, University of Prince Edward Island, 550 University Avenue,
Charlottetown, Prince Edward Island, C1A 4P3, Canada
^b NRC Institute for Marine Biosciences/Institut des biosciences marines CNRC,
1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada

Abstract
Two antimicrobial peptides from haemocytes of the American lobster, Homarus americanus H. Milne Edwards 1837, were isolated and partially characterised e the first such description for this species. CAP-2, an approximately 12 kDa peptide, contained amino acid sequences corresponding to the predicted sequence for Hoa-crustin. Crustins are whey acidic protein (WAP) domain - containing peptides isolated from crustacean haemocytes. CAP-2 did not have any activity towards the Gram positive coccus Aerococcus viridans unlike carcinin, a crustin from Carcinus maenas haemocytes, which may partially explain the lobster’s susceptibility to this bacterium. A second peptide, CAP-1, was a multimer composed of 4e6 kDa subunits with similarities to amphibian temporins. CAP-1 may represent a novel group of antimicrobial peptides for marine invertebrates and has been tentatively named ‘homarin’. Homarin had bacteriostatic activity against some Gram negative bacteria and both protozoastatic and protozoacidal activity against two cultured scuticociliate parasites Mesanophrys chesapeakensis and Anophryoides haemophila, the latter a significant pathogen of H. americanus.
ª 2008 Elsevier Ltd. All rights reserved.

E-mail address: abattison@upei.ca (A.L. Battison).