Isolation, Purification, and Some Properties of Two Viruses from Cultivated Cymbidium Orchids

Two distinct viruses have been isolated from cultivated Oymbidium plants in Australia. Each virus isolate has been transmitted to herbaceous plants, has been purified, and high-titre antiserum has been produced. One isolate has been identified as a serotype of tobacco mosaic virus; the other is suspected of being Oymbidium mosaic virus and has flexuous rods about 13 by 475 mIL. Electron micrographs of particles of the latter show that they have hollow central canals and consist of helical structures with a pitch of approximately 2� 8 mIL' Results indicate that inoculation to herbaceous plants and electron-microscopic examination and serological testing of leaf extracts can be used as methods for the routine indexing of Oymbidium plants.</jats:p

The Serological Properties of Eutypa Armeniacae Mycelium and Ascospores

In epidemiological studies of the apricot vascular pathogen Eutypa armeniacae Hansf. &amp; Carter in this laboratory (Moller and Carter 1965; Carter and Moller 1967) some diagnostic problems have been encountered. The pathogen is sufficiently variable in culture to be confused with other Ascomycetes, such as species of Valsa and Cryptovalsa which may colonize dead vascular tissue below pruning wounds which have been invaded by E. armeniacae. It is also difficult to differentiate E. armeniacae ascospores from those of related Ascomycetes caught in spore traps during wet weather.</jats:p

Purification of Potato Virus X and Preparation of Infectious Ribonucleic Acid by Degradation With Lithium Chloride

Potato virus X (PVX) was one of the first plant viruses to be partially purified (Bawden and Pirie 1938). Purification by precipitation with salt solutions, however, resulted in aggregation of the particles. which became entwined to form extensive rope and netlike structures (Kleczkowski and Nixon 1950). Markham (1959) suggested that the problem of aggregation and the formation of gels when the virus is treated with salt solutions has prevented PYX from being extensively studied</jats:p