FAMILY MARMORACEAE 



1169 



Geographical distribution: England, 

 Scotland, Australia. This virus has been 

 found only in greenhouses. 



Induced disease : In tobacco, necrosis 

 of midrib and larger veins of first-de- 

 veloped pair of leaves, between Novem^ 

 ber and February. Virus also in roots 

 of many healthy -looking plants through- 

 out the j'ear. Upon artificial inoculation 

 of foliage, numerous small brown necrotic 

 local lesions are produced. Yield of virus 

 from infected plant 0.02 mg per cc of ex- 

 pressed juice, on the average. 



Transmission : By contamination of soil 

 with virus. No insect vector is known. 

 Experimentally, by inoculation of ex- 

 pressed juice. 



Serological reactions : Precipitates with 

 homologous antiserum. No cross reac- 

 tion with tomato bush5^-stunt or tobacco- 

 mosaic viruses. 



Immunological relationships : Protec- 

 tion tests show lack of relationship to 

 tobacco-mosaic virus, tobacco-ringspot 

 virus, tomato-ringspot virus, cucumber- 

 mosaic virus, and the severe-etch strain 

 of tobacco-etch virus. 



Thermal inactivation : At 90 to 92° C 

 in 10 minutes. 



Filterability : Average particle diame- 

 ter 20 to 30 millimicrons as determined by 

 filtration through Gradocol membranes; 

 other reports give diameter as 13 to 20 

 millimicrons by filtration (14 to 19 milli- 

 microns by radiation experiments, about 

 20 millimicrons from electron micro- 

 graphs). 



Other properties : Infectious after stor- 

 age for months in dried leaves and after 

 storage for half a j'ear in absolute ethyl 

 alcohol at room temperature. Specific 

 gravity 1.3. More soluble in ammonium 

 sulfate solutions at 0° C than at room 

 temperature. Composition : Carbon 44.8 

 to 45.3 per cent, nitrogen 15.5 to 16.5 per 

 cent, hydrogen 6.5 to 7.0 per cent, phos- 

 phorus 1.4 to 1.7 per cent, sulfur 1.1 to 

 2.0 per cent, carbohydrate 7.0 to 9.0 per 

 cent ; ash 5.8 to 7.0 per cent (3 to 5 per 

 cent after prolonged dialysis at pH 3). 

 Nucleic acid of the ribose type has been 



isolated. No anisotropy of flow in solu- 

 tion but crj'stals are birefringent, show- 

 ing sharp extinctions parallel to, and at 

 right angles to, the plane of the crj^stal 

 when examined edge-on in a polarizing 

 microscope. Sedimentation constant, 

 S2o° = 112 X 10~i'; in other preparations 

 a crystalline component with sedimenta- 

 tion constant 130 X 10"^' and an amor- . 

 phous component with sedimentation 

 constant 58 X lO^^^ have been reported, 

 as well as small amounts of a substance 

 with sedimentation constant 220 X 10~^^ 



Strains : Isolates of tobacco-necrosis 

 virus serologically distinct but not other- 

 wise different from each other appear to 

 impl.y the existence of several strains of 

 this virus, or of a closely related group of 

 viruses, in England. 



Literature: Bawden, Brit. Jour. Exp. 

 Path., 22, 1941, 59-70; Bawden et al., 

 ibid., 23, 1942, 314-328; Cohen, Proc. Soc. 

 Exp. Biol, and Med., 4S, 1941, 163-167; 

 Lea, Nature, U6, 1940, 137-138; Pirie et 

 al., Parasitol., 30, 1938, 543-551; Price, 

 Am. Jour. Bot., 25, 1938, 603-612; Am. 

 Jour. Bot., 27, 1940, 530-541; Arch. 

 Virusf., 1, 1940, 373-386; Price and 

 Wyckoff, Phytopath., 29, 1939, 83-94; 

 Smith, Parasitol., 29, 1937, 70-85; 29, 

 1937, 86-95; Smith and Bald, Parasitol., 

 27, 1935, 231-245; Smith and MacCle- 

 ment, Parasitol., 32, 1940, 320-332. 



5a. Marmor dodecahedron H. (loc.cit., 

 30). From Greek dodekahedron, dodeca- 

 hedron. 



Common name : Tomato bushy-stunt 

 virus. 



Hosts : SOLAN ACE AE — Lycopersicon 

 esculentum Mill., tomato. Experiment- 

 ally, also SOLA N ACE AE— Datura stra- 

 monium L.; Nicotiana glutinosa L.; A. 

 langsdorffii Weinm.; A^. tabacum L., to- 

 bacco; Solarium nigrum L. LEGU- 

 MINOSAE—Phaseolus vulgaris L., bean ; 

 Vigna sinensis (L.) Endl., cowpea. 

 COMPOSIT AE— Zinnia elegans .Jacq., 

 zinnia. 



Geographical distribution : British 

 Isles. 



