Factors influencing immune electron microscopy of flexuous potato viruses.

Effects of pH of extraction buffers, pH and titer of trapping antisera and their combinations, virus acquisition time and virus host on the trapping efficiency of flexuous potato viruses X, S and Y (PVX, PVS and PVY) in immune electron microscopy were evaluated. Addition of ethylene-diamine-tetraacetic acid to the extraction buffer improved trapping of PVY, adversely affected PVS but not PVX. Combinations of antisera had differential adverse effect on trapping which was maximum with the mixture of three antisera. Mixture of antisera to PVX and PVY had the least adverse effect on trapping of PVX and PVY as compared to the mixture with PVS antiserum. Trapping of PVX and PVY was good and almost at par at all the dilutions of the antisera while that of PVS was good up to 1000-fold only. Prolonged virus acquisition time significantly increased the number of virions trapped. Trapping was affected both by the pH of the antiserum and the extraction buffer, while in the case of PVY it was also affected by the host species.