Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 2001
Publication Date: September 15, 2001
Citation: Rhoads, M.L., Fetterer, R.H., Urban Jr, J.F. 2001. Release of hyaluronidase during in vitro development of ascaris suum from the third-to fourth-larval stage. Parasitology Research 87(9):693-697.
Interpretive Summary: The swine round worm, Ascaris suum, is responsible for significant economic losses by reducing production efficiency and causing organ condemnations at slaughter due to pathology produced by parasite larval stages. Development of novel controls can be enhanced by a knowledge of the biochemical mechanism underlying the process of molting, an essential process in the growth and development of all nematodes. The results demonstrate that A. suum produces an enzyme coincident with molting. Inhibition of this enzyme activity may interfere with the molting process.
An enzyme that degraded the glycosaminoglycan hyaluronic acid was released during in vitro development of Ascaris suum L3 to L4; the enzyme did not hydrolyze the glycosaminoglycan chondroitin sulfate A. One molecular form of hyaluronidase was detected with a molecular weight estimated at 47.8 kDa by sucrose density gradient centrifugation and at 55.0 kDa by substrate eSDS-PAGE zymography. Activity of the enzyme was optimum between pH 5.0 and 6.0; the enzyme was active at neutral pH. Hyaluronidase activity was not affected by 5-mM concentrations of cupric sulfate, zinc chloride, calcium chloride, manganese chloride or EDTA; NaCl had no effect on enzyme activity at concentrations from 0.2 to 1.0 M. The highest level of hyaluronidase was present in culture fluids collected between day 4 and 6 of in vitro culture; this period corresponded with that of the highest rate of increase in the percentage of L4. The presence or absence of hyaluronic acid play key roles in basic developmental processes of vertebrates; developmental processes occurring during the transition of A. suum L3 to L4 may likewise depend on hyaluronidase. In addition, the infection process of a number of organisms, including some nematodes, depends on hyaluronidase; A. suum may utilize hyaluronidase to facilitate host migration.