(I) Effect of Various Additives on the Stability of Freeze-Dried Small Isometric Plant Viruses(Seminar on "Techniques for Maintenance of Biological Activities")

Abstract

The infectivity of purified southern bean mosaic virus (SBMV) in 10mM sodium phosphate buffer, pH 7.0, decreased to 11% after freeze-drying. Surcose density gradient sedimentation profiles and electron microscopy clearly showed partial alteration of virions by freeze-drying. And such virions were found to be susceptible to RNase or sodium dodecyl sulfate. However, RNA isolated from such virions possessed the infectivity to the same level of RNA isolated from non-freeze-dried virions. Virions were protected by addition of various additives prior to freeze-drying. Upon the storage at 65℃, the preparation of freeze-dried virus lost the infectivity in one day. RNA isolated from such virions were degradated, and had no infectivity. Whereas virions with 0.5% lysine were retained the conformation, and mantained higher infectivity than the preparation with no additive. Also, the infectivity of RNA was gradually lost upon storage. Freeze-dried carnation mottle virus upon the storage at 65℃, showed the similar tendency to SBMV.