Effect of protease class-specific inhibitors on in vitro development of the third- to fourth-stage larvae of Ascaris suum.
Third-stage larvae (L3) of Ascaris suum develop and molt to fourth-stage larvae (L4) during in vitro cultivation; consistently greater than 80% of the larvae develop to L4 during 7 days in culture (DIC). To assess the role of proteases in this process, the effect of protease class-specific inhibitors was studied. The presence of either a serine protease inhibitor (AEBSF, 100 microM) or an aspartic protease inhibitor (pepstatin A, 100 microM) had no effect on the percentage of L4 after 7 DIC. However, the presence of either a cysteine protease inhibitor (Z-Phe-Ala-FMK, 100 microM) or an aminopeptidase inhibitor (amastatin, 100 microM) resulted in 77% and 34% reductions, respectively, in the percentage of L4 compared to untreated cultures; viability of the larvae was not affected. The effect of Z-Phe-Ala-FMK on molting was time and dose dependent. In contrast to Z-Phe-Ala-FMK, E-64, another specific inhibitor of cysteine proteases, had no effect on molting. The data support a role for an aminopeptidase and suggest a role for a cysteine protease in the development of the L3 to L4 stage of A. suum.
Livestock and Poultry Sciences Institute, United States Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705, USA.
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D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017165:Ascaris suum / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D004396:Coloring Agents / Q000737:chemistry; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007659:Ketones / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D009068:Movement / Q000187:drug effects; D010436:Pepstatins / Q000494:pharmacology; D010455:Peptides; D011480:Protease Inhibitors / Q000494:pharmacology*; D013450:Sulfones / Q000494:pharmacology; D013552:Swine; D013778:Tetrazolium Salts / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry; D014361:Trypsin Inhibitors / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D007659:Ketones; D010436:Pepstatins; D010455:Peptides; D011480:Protease Inhibitors; D013450:Sulfones; D013778:Tetrazolium Salts; D013844:Thiazoles; D014361:Trypsin Inhibitors; C014195:Streptomyces pepsin inhibitor; C057383:MDL 201053; C002010:4-(2-aminoethyl)benzenesulfonylfluoride; C016977:amastatin; C022616:thiazolyl blue; C031375:pepstatin