Porter R D, Guild W R
J Virol. 1976 Aug;19(2):659-67. doi: 10.1128/JVI.19.2.659-667.1976.
The growth of pneumococcal phages at high cell and phage densities is enhanced strongly by the substitution of potassium for sodium in the medium. Initial titers of 2 X 10(10) to 4 X 10(10) PFU/ml are readily obtained, and concentrated stocks are stable in a storage buffer described here. The mechanism of the cation effect is obscure. Phages omega3 and omega8 each have linear double-stranded DNA of 33 X 10(6) daltons per particle, with an apparent guanine plus cytosine content of 47 to 49 mol%, as determined by buoyancy and melting temperature, but with an unusual absorbance spectrum. Efficiency of plating is high if sufficient time is allowed for a relatively slow adsorption, which differs several-fold in rate between the two phages. Morphologically, these and other pneumococcal phages are similar to coliphage lambda but with a longer tail and tail fiber. Upon UV inactivation, omega3 and omega8 have D37 values of 33 and 55 J/m2, respectively, and each shows multiplicity reactivation. A total of 13 ts mutants have been isolated from the two phages, representing only two complementation groups; complementation and recombination occur between omega3 and omega8 mutants. Both phages provoke high-titer antisera with extensive cross-reactivity against a number of newly isolated pneumococcal phages.
在培养基中用钾替代钠可显著增强肺炎球菌噬菌体在高细胞密度和高噬菌体密度下的生长。很容易获得初始滴度为2×10¹⁰至4×10¹⁰ PFU/ml的噬菌体，且在此处所述的储存缓冲液中浓缩噬菌体原液是稳定的。阳离子效应的机制尚不清楚。噬菌体omega3和omega8每个粒子都有线性双链DNA，分子量为33×10⁶道尔顿，根据浮力和熔解温度测定，鸟嘌呤加胞嘧啶的表观含量为47%至49摩尔%，但其吸收光谱异常。如果给予足够时间进行相对缓慢的吸附，其平板接种效率很高，两种噬菌体的吸附速率相差几倍。从形态学上看，这些及其他肺炎球菌噬菌体与大肠杆菌噬菌体λ相似，但尾部和尾丝更长。经紫外线灭活后，omega3和omega8的D37值分别为33和55 J/m²，且均表现出多重复活现象。从这两种噬菌体中总共分离出13个温度敏感突变体，仅代表两个互补群；omega3和omega8突变体之间发生互补和重组。这两种噬菌体都能引发高效价抗血清，对许多新分离的肺炎球菌噬菌体具有广泛的交叉反应性。
