Effect of protease class-specific inhibitors on in vitro development of the third- to fourth-stage larvae of Ascaris suum

• Published in: The Journal of parasitology Vol. 84; no. 4; pp. 686 - 690
• Main Authors: Rhoads, M.L. (Parasite Biology and Epidemiology Laboratory, USDA, ARS, Beltsville, MD.), Fetterer, R.H, Urban, J.F. Jr
• Format: Journal Article
• Language: English
• Published: Lawrence, KS American Society of Parasitologists 01-08-1998
• Subjects: AMINOPEPTIDASA; AMINOPEPTIDASE; Animals; Anti-Bacterial Agents - pharmacology; ASCARIS SUUM; Ascaris suum - drug effects; Ascaris suum - enzymology; Ascaris suum - growth & development; ASPARTIC PROTEINASES; Biological and medical sciences; BIOLOGICAL DEVELOPMENT; Coloring Agents - chemistry; Cysteine proteinase inhibitors; Cysteine Proteinase Inhibitors - pharmacology; CYSTEINE PROTEINASES; DESARROLLO BIOLOGICO; Development; DEVELOPPEMENT BIOLOGIQUE; Dipeptides - pharmacology; Dose-Response Relationship, Drug; Enzymes; EXPERIMENTACION IN VITRO; EXPERIMENTATION IN VITRO; Fundamental and applied biological sciences. Psychology; IN VITRO EXPERIMENTATION; INHIBIDORES DE PROTEINASAS; INHIBITEUR DE PROTEINASES; Intestinal volvulus; Invertebrates; Ketones; Ketones - pharmacology; Larva - drug effects; Larva - growth & development; LARVAE; Larval development; LARVAS; LARVE; Life cycle. Embryology. Development; Molting; MOULTING; Movement - drug effects; MUDA; MUE; Nemathelminthia. Plathelmintha; NEMATODA; Nematode larvae; Nematodes; Parasitology; Pepstatins - pharmacology; Peptides; Physiology. Development; PROTEASAS; PROTEASE; Protease Inhibitors - pharmacology; PROTEASES; PROTEINASE INHIBITORS; Sulfones - pharmacology; Swine; Tetrazolium Salts - chemistry; Thiazoles - chemistry; Trypsin Inhibitors - pharmacology; Life history; Cysteine; Enzyme; Aminopeptidases; Serine; Enzyme inhibitor; Parasite; Experimental study; In vitro; Molt; Peptidases; Larva; Helmintha; Ascaris suum; Development; Hydrolases; Nemathelminthia; Aspartic acid; Invertebrata; Nematoda
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3284570

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 µM) or an aspartic protease inhibitor (pepstatin A, 100 µM) 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 µM) or an aminopeptidase inhibitor (amastatin, 100 µM) 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.