TABLE 4.

Properties of eight fractions of the surface-active extract obtained by RP-HPLC

FractionRP-HPLC retention time (min)HaloaDrop collapsebFoam formationcCessation of zoospore motilitydZoospore lysisd
10-3e
23-15.5+f
315.5-17.2+
417.2-19.7+++
519.7-21.6++++
621.6-24+++
724-26.4++±g
826.4-31.5+++++
Water
  • a Evaluated on SW medium after 3 days at 25°C. +, present; −, absent.

  • b Dissolved fractions were tested on an oily surface for the ability to cause the collapse of a drop of water.

  • c Foam formation after dissolved fractions were vigorously shaken.

  • d Zoospore motility and lysis were observed microscopically after the dissolved fractions were mixed with zoospore suspensions of P. infestans in a 1:1 (vol/vol) ratio.

  • e −, negative reaction.

  • f +, positive reaction.

  • g Lysis was not complete, and the effect resembled leakage at one point in the zoospore membrane.