Soloff B L, Rado T A, Henry B E, Bates J H
J Virol. 1978 Jan;25(1):253-62. doi: 10.1128/JVI.25.1.253-262.1978.
Large-scale propagation of mycobacteriophage R1 in broth culture has allowed the isolation of quantities of virus sufficient for characterization of its nucleic acid and lipid components as well as investigation of its ultrastructural attributes. Analysis of R1 DNA indicates that it is double stranded and possesses a molecular weight of 2.5 X 10(7) and a guanine-plus-cytosine content of 65.7 +/- 0.5%. The lipid fraction of R1 accounts for 14% of the total dry weight of the virus, 20% of which was identified as free or esterified sterols. A rapid loss of viral titer occurred after seconds of exposure to organic solvents. This result suggests that the lipid fractions of R1 is essential for its infectivity. Electron microscopic investigation of solvent-extracted R1 showed extensive deterioration of its normal morphology, including nucleocapsid disintegration and base plate separation. Routine phosphotungstate preparations demonstrated a particle with an oval head and a noncontractile tail. Altering the pH of the phosphotungstate negative stain from neutrality damage the viral particles. Uranyl formate-contrasted specimens displayed an elongated hexagonal nucleocapsid with a neck region; the cross-striated tail possessed a starlike base plate.
分枝杆菌噬菌体R1在肉汤培养中的大规模繁殖使得能够分离出足够数量的病毒，用于其核酸和脂质成分的表征以及超微结构特征的研究。对R1 DNA的分析表明，它是双链的，分子量为2.5×10⁷，鸟嘌呤加胞嘧啶含量为65.7±0.5%。R1的脂质部分占病毒总干重的14%，其中20%被鉴定为游离或酯化固醇。暴露于有机溶剂数秒后，病毒滴度迅速下降。这一结果表明，R1的脂质部分对其感染性至关重要。对溶剂提取的R1进行电子显微镜研究显示，其正常形态出现广泛退化，包括核衣壳解体和基板分离。常规磷钨酸盐制备显示出一个具有椭圆形头部和不可收缩尾部的颗粒。将磷钨酸盐负染的pH从中性改变会损害病毒颗粒。甲酸铀对比标本显示出一个带有颈部区域的细长六边形核衣壳；横纹尾部有一个星形基板。
