The purification and some properties of cocoa necrosis virus, a serotype of tomato black ring virus
Cocoa necrosis virus (CNV) was transmitted by sap inoculation to twelve of twenty-one species tested. It was propagated and assayed in Phaseolus vulgaris. Sap from P. vulgaris was infective after dilution to 10 exponent -3 but not 10 exponent -4, after 10 min at 60 centigrade grade but not 65 centigrade grade, and after 4 but not 7 days at 20-24 centigrade grade. Lyophilized sap from P. vulgaris was infective after 2 years in vacuo. Virus was prepared by extracting infected leaves of P. vulgaris with 0.1 M phosphate (pH 7.5) containing 0.05 M ethylene diamine tetra-acetate and 0.02 M thioglycollate. After clarification with n-butanol, virus was purified by precipitation with polyethylene glycol and several cycles of differential centrifugation. Such preparations were very infective and contained numerous particles, 24-26 nm in diameter with a hexagonal profile, which sedimented as two components with sedimentation coefficients (S 20, W) of 101 S and 129 S. The absorption spectra of both components with maximum and minimum absorption at 259 and 240 nm respectively were typical of nucleoproteins (101 S component, A 260/280 = 1.63; A 260/240 = 1.40:129 S component; A 260/280 = 1.78; A 260/240 = 1.58) and indicated nucleic acid contents of ca. 35 per cent for the 129 S component and ca. 20 per cent for the 101 S component; values calculated from the sedimentation coefficients were 41 and 30 per cent respectively. Only the 129 S component seemed to be infective and was not more so when mixed with 101 S component. Both components contained a single protein subunit weighing ca. 60.000 daltons. Under certain conditions sap fractionated without butanol gave virus preparations containing empty protein shells (54 S) and small spherical particles (20-30 S) ca. 12 nm diameter. CNV is a serotype of tomato black ring virus and is distantly related to Hungarian chrome mosaic virus
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| Format: | biblioteca |
| Published: |
1972
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| Subjects: | THEOBROMA CACAO, NECROSIS, VIROSIS, DIAGNOSTICO, TECNICAS INMUNOLOGICAS, SAVIA, HUESPEDES, |
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