Fixation and electron microscopy of the Rothamsted culture of henbane mosaic virus

Thin sections of tissue infected by viruses of the potato virus Y (PVY) group often fail to show virus particles. Henbane mosaic virus (HMV) is more concentrated in infected tissue than most PVY group viruses and seemed a suitable subject for electron microscopy. We failed to detect any particles after tissues were subjected to a commonly used double fixation technique but found them in tissue fixed with osmic acid; parallel results were found when purified virus preparations were similarly treated.

This paper reports some details of the fine structure of infected tissue and the effect of fixation on virus within the host cell and in purified preparations.

The Rothamsted culture of HMV used has been maintained in Nicotiana tabacum, cv. White Burley, usually infected by mechanical inoculation but occasionally with aphids. The virus was purified from this host by a modification of Damirdagh & Shepherd's (1970) procedure using borate instead of phosphate buffer throughout, and infectivity was confirmed by inoculation on Nicotiana sylvestris.