Versuche zur Vermehrung infektiöser Ribonukleinsäure aus Tabakmosaikvirus in Chlorella

Abstract

Experiments on the increase of infective ribonucleic acid from tobacco mosaic virus in Chlorella 1. 1. Chlorella pyrenoidosa was tried as host for tobacco mosaic virus (TMV). Synchronized as well as continuous light cultures were treated with free ribonucleic acid (RNA) of TMV and assayed for virus infectivity on Nicotiana tabacum var. Xanthi. 2. 2. A concentration of 1.5 μg of TMV-RNA per ml did not inhibit growth of Chlorella cultures and did not lead to visible damage of the cells. A treatment of synchronized Chlorella cultures with TMV-RNA over a long period of time did not render the cells asynchronous. 3. 3. The biological activity of TMV-RNA decreased by 50% after 3–5 h incubation in culture medium at 30°. This inactivation of TMV-RNA was not markedly influenced by the presence of intact Chlorella cells. However, in the presence of Chlorella-homogenate, TMV as well as free RNA were strongly inactivated. 4. 4. From inoculated Chlorella cultures newly synthesized TMV-RNA could be extracted in increasing concentrations depending on the duration of the incubation period. The yields of infective RNA were small (5·10 8 Chlorella cells in 4 ml of inoculated culture, homogenized gave rise to 5–19 lesions per 25 tobacco leaves) and not always reproducible. Chlorella cultures inoculated for two life-cycles, with the TMV-RNA maintained at a constant level of biological activity showed the greatest number of lesions on tobacco plants. 5. 5. The lesions on N. tabacum var. Xanthi caused by extracts of inoculated Chlorella differed from those caused by the RNA of the TMV strain vulgare. They appeared later (8–14 days as compared to 3–4 days) and were larger in size. When inoculated singly to N. tabacum var. Samsun they gave rise to a systemic infection comparable to the systemic infection resulting from inoculation of this tobacco species with TMV vulgare-RNA. 6. 6. The yield of TMV-RNA from inoculated Chlorella cells is compared with the yield of TMV-RNA from inoculated tobacco leaf cells. 7. 7. The presence of infectivity in Chlorella cells after inoculation with TMV-RNA demonstrated an extension of the host-range for TMV from higher plants to algae and concommitantly decreased the host-specificity of the virus.