FIG. 7.
Nematotoxic activity of heterologous PII. The proteases were incubated with the nematode P. redivivus in microtiter wells. After 20 to 22 h the number of mobile and immobile (i.e., with arrested movements) nematodes were counted in a light microscope. Indicated significance levels are from χ2 tests (df = 1) comparing the frequencies of mobilized and immobilized nematodes in treated versus control samples (without enzymes). NS, not significant. PII, PII produced in A. niger; PII∗, boiled PII (10 min); PK, proteinase K; Try, trypsin; C, control (buffer). The proteolytic activities of the added enzymes, as measured by using the substrate Azocoll, are indicated.