Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 6, 1998
Publication Date: N/A
Interpretive Summary: Like many gastrointestinal nematodes, the sheep stomach worm, Haemonchus contortus, survives in the reduced oxygen tension of the ruminant gut. The mechanism by which H. contortus has adapted to these low oxygen conditions is unknown. H. contortus synthesizes a protein with characteristics of globin, a high affinity oxygen binding molecule. Though the function of this protein in nematode physiology remains unclear, previous studies have shown that globin is a major constituent of the parenteric fluid, and may be involved in oxygen uptake in this nematode. In this study, we have cloned the full length globin molecule, localized the globin protein within the adult parasite using anti-globin antibody, and identified cells containing the globin mRNA message with globin gene fragments generated in PCR assays.
Technical Abstract: Amino acid sequencing was performed on three peptides resulting from proteolytic digest of the 33 kDa purified globin molecule. Homologous oligonucleotide primers were prepared using this data and used in PCR assays, producing a 513 bp fragment. When sequenced, the fragment contained significant homology with other nematode globins, especially Trichostrongylus colubriformis and Ostertagia ostertagi. The central 231 b PCR fragment hybridized to mRNA in the hypodermis of the adult worm. Polyclonal antibodies prepared in rabbits against the purified protein bound to globin in the cuticle, hypodermis, and the muscle layer of the adult nematode.