scholarly journals Competition between Infectious Tobacco Mosaic Virus Nucleic Acid and Intact Virus on Nicotiana glutinosa

Nature ◽  
1962 ◽  
Vol 193 (4818) ◽  
pp. 908-908 ◽  
Author(s):  
JIA-HSI WU ◽  
IRVING RAPPAPORT
Keyword(s):  
Nucleic Acid ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Nicotiana Glutinosa ◽  
Intact Virus

Die Bildung der infektiösen Ribonucleinsäure während der Vermehrung des Tabakmosaikvirus

1960 ◽  
Vol 15 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Reto Engler ◽  
Gerhard Schramm
Keyword(s):  
Nucleic Acid ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Ribonucleic Acid ◽  
Virus Concentration ◽  
Free Virus ◽  
Direct Extraction ◽  
Nicotiana Glutinosa ◽  
General Hypothesis ◽  
Phenol Extraction

Young plants of Nicotiana tabacum (Var. Samsun) were infected with tobacco mosaic virus and kept at a constant temperature between 23 and 27°C and at constant illumination. The virus concentration was determined by bioassay on Nicotiana glutinosa. An exponential increase in virus concentration occurred 20-30 hours after infection. This latent period is significantly shorter after infection with virus ribonucleic acid. Probably the nucleic acid has to be liberated from the nucleoprotein before multiplication can start. The formation and multiplication of free virus ribonucleic acid could be demonstrated earlier than the formation of the complete virus. Infectious nucleic acid was measured by direct extraction of the plants with phenol. Nucleic acid included in the virus was determined after degradation of the free ribonucleic acid by incubation at 37°C and subsequent phenol extraction. The amount of free ribonucleic acid reaches a maximum 40 hours after infection and decreases afterwards to the extent as the virus bound ribonucleic acid increases. A general hypothesis for the biosynthesis of tobacco mosaic virus is given.

scholarly journals The Iron Content of Tobacco Mosaic Virus and Some Properties of Its Infectious Nucleic Acid

1958 ◽  
Vol 233 (6) ◽  
pp. 1415-1420
Author(s):  
Hubert S. Loring ◽  
Saad Al-Rawi ◽  
Yasuo Fujimoto
Keyword(s):  
Nucleic Acid ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Iron Content

scholarly journals STUDIES ON THE AGGREGATION REACTIONS AND BASIC DYE BINDING OF TOBACCO MOSAIC VIRUS

1956 ◽  
Vol 39 (3) ◽  
pp. 437-471 ◽  
Author(s):  
Richard S. Welsh
Keyword(s):  
Methylene Blue ◽  
Nucleic Acid ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Ultraviolet Absorption ◽  
Hydrogen Ions ◽  
Irreversible Binding ◽  
Concentrated Solutions ◽  
Polymeric Form ◽  
End To End

1. Aqueous solutions of tobacco mosaic virus were found to undergo a number of spontaneous changes on standing in the cold. The results of pH measurements, acid and base titrations, intrinsic viscosity determinations, studies on the irreversible binding of methylene blue with the virus, ultraviolet absorption, and the extent of nucleic acid splitting by heat denaturation indicated the occurrence of two successive reactions, the first one causing the release of hydrogen ions and a greater lability of the nucleic acid, and the second one, which involved end-to-end dimerization and which took place after 8 days of standing, requiring hydrogen ions. 2. The first over-all reaction was found to be a mixture of various types of reversible disaggregation and aggregation reactions, the nature of which depended on the pretreatment, the TMV concentration, the time of standing, and the phosphate concentration. For longer times of standing at high protein concentration a sudden drop in ultraviolet absorption is noted after dilution; also the drops in viscosity and pH are largest with a steep rise following, indicating the greatest breakup of end-to-end aggregates with formation of the side-to-side type. For concentrated solutions of TMV in water which have not stood long no drop in ultraviolet absorption is noted on dilution; the decrease in the other quantities is less, indicating that only a less extensive breakdown of end-to-end aggregates occurs. Addition of phosphate to concentrated solutions of TMV causes formation of side-to-side aggregates which break up on dilution. 3. Using the results for the pH increase and the viscosity increase in a given time interval for a given TMV preparation and also the slope of the corresponding titration curve at the pH mean, a value for the number of hydrogen ions taken up per TMV monomer in the formation of the end-to-end dimer was finally calculated. The average result obtained for two preparations was 3300. 4. Methylene blue, in the polymeric form, was demonstrated to cause complete irreversible conversion of TMV monomers to end-to-end dimers. At dye concentrations above 10–4 M, higher TMV polymers are formed, but these are broken down to dimers on removal of free dye by dialysis. The irreversible binding ratios were shown to be decreased in accordance with the extent of the end-to-end aggregation of the preparation at the time of the experiment, which is in agreement with the concept that the irreversibly bound dye polymers go into the junction formed between two interacting TMV monomers. On the basis that only the monomers initially present in solution can react, maximum binding ratios corresponding to complete conversion of monomers to dimers were calculated from the observed irreversible binding ratios and from the fraction of dimers initially present which was obtained from viscosity data. The average result for three preparations in different states of aggregation was calculated to be 6565 for tetrameric binding or 3230 for dimeric binding, which agrees closely with the result obtained for the uptake of hydrogen ions per TMV monomer in the spontaneous dimerization.

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