Identification of cpn60 from the nematode Plectus acuminatus. An adapter ligated complementary deoxyribonucleic acid (cDNA) library was constructed from 7000 P acuminatus individuals using the Marathon™ cDNA Amplification Kit (CLONTECH Laboratories, Palo Alto, CA, USA). Cpn60 was amplified, with degenerative primers, in a touchdown polymerase chain reaction and forthcoming bands purified, cloned (pGEM-T, Promega, Southampton, Hampshire, UK), and sequenced. The full-length P acuminatus cpn60 sequence was determined on both strands of the 5′ fragment, the 3′ fragment, and the 5′-3′ overlap region resulting in a final contig of 2068 bp (European Molecular Biology Laboratory/Genbank accession no. AJ130877). The translation is given in panel A with the putative N-terminal mitochondrial targeting signal boxed. Homology searches using the BlastN and BlastP algorithms (Altschul et al 1990; Gish and States 1993) identified the sequence to be closely related to 2 further nematodes (panel A). Pairwise comparisons of the deduced amino acid sequence were calculated from 3 nematode species and the human Cpn60, where the first number represents percent identity and the second, percent similarity scores (panel B). A ClustalW multiple alignment was used to construct a Cladogram of the P acuminatus Cpn60 amino acid sequence and 12 further Cpn60s from a variety of species to highlight phylogenetic relationships (panel C)