title: Single-stranded endonuclease activity in the excretory--secretory products of Trichinella spiralis and Trichinella pseudospiralis.
abstract: A novel acidic extracellular single-stranded endonuclease was demonstrated for the first time in the excretory-secretory (E-S) products of 2 species of Trichinella. Unlike the double-stranded endonuclease reported earlier, the single-stranded molecule is divalent cation independent and is detected in both T. spiralis and T. pseudospiralis E-S products. It hydrolysed single-stranded DNA and RNA at comparable rates. The single-stranded endonuclease was sensitive to inhibition by Zn2+ and to high concentrations of NaCl. Zymographic analysis indicated that it was encoded by at least 3 peptides of Mr approximately 50-60 kDa. The rate of hydrolysis of single-stranded targets by the E-S products was substantially higher than that of the double-stranded molecule. Due to the differences in peptide profile, divalent cation dependence, and species-specific expression, the single and double-stranded endonucleases are likely to be encoded by different proteins and may have different functions.
authors.affiliation: Department of Zoology, The University of Hong Kong, Pokfulam, China.
authors.forename: C H
authors.initials: CH
authors.lastname: Mak
authors.forename: Y Y
authors.initials: YY
authors.lastname: Chung
authors.forename: R C
authors.initials: RC
authors.lastname: Ko
mesh_terms: D000818:Animals; D002413:Cations, Divalent / Q000378:metabolism; D004720:Endonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015801:Helminth Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D013045:Species Specificity; D014234:Trichinella / Q000201:enzymology*; D017160:Trichinella spiralis / Q000201:enzymology*; D014235:Trichinellosis / Q000469:parasitology*
chemical_list: D002413:Cations, Divalent; D015801:Helminth Proteins; D004720:Endonucleases