title: Metalloproteases and egg-hatching in Pediculus humanus, the body (clothes) louse of humans (Phthiraptera: Insecta).
abstract: To investigate the biochemical components of egg-hatch in the body louse, Pediculus humanus, egg-shell-washings (ESW) were collected during the first 2 h post-hatching and analysed by gelatin SDS-PAGE. These ESW contained proteases with molecular mass in the range of 25-100 kDa; the most abundant proteases were approximately 25 kDa. The 3 main regions of protease activity in the one-dimensional gelatin SDS-PAGE gels resolved to at least 23 distinct regions of protease activity when analysed by two-dimensional gelatin SDS-PAGE, with iso-electric points spread over the entire 3 to 10 pH range. Mechanistic characterization indicated that the ESW contained proteases of the metallo-class, inhibited by both 1,10-phenanthroline and EDTA. Several protease inhibitors were tested for their ability to inhibit louse egg-hatch in vitro. The metalloprotease inhibitor 1,10-phenanthroline and the aminopeptidase inhibitor bestatin significantly inhibited (P<0.05) louse egg-hatch (100% and 58%, respectively). The presence of metalloproteases at the time of egg-hatch and the inhibition of egg-hatch in P. humanus by metalloprotease inhibitors suggests a crucial role for these proteases in the hatching of this medically important parasite.
authors: Centre for Animal Biotechnology, School of Veterinary Science, The University of Melbourne, Melbourne, 3010, Australia. v.bowles@vet.unimelb.edu.au
authors: V M
authors: VM
authors: Bowles
authors: A R
authors: AR
authors: Young
authors: S C
authors: SC
authors: Barker
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D045726:Metalloproteases / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D010063:Ovum / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D010374:Pediculus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011817:Rabbits
chemical_list: D011480:Protease Inhibitors; D045726:Metalloproteases