Agabian-Keshishian N, Shapiro L
J Virol. 1970 Jun;5(6):795-800. doi: 10.1128/JVI.5.6.795-800.1970.
The Caulobacter crescentus bacteriophage phiCbK was studied with respect to the physical and chemical properties of both the phage and its deoxyribonucleic acid (DNA). Electron micrographs reveal the phage to be among the largest DNA bacteriophages reported, with head dimensions of 64 by 195 nm and a flexible tail 275 nm in length. The phage is composed of 57% DNA. This DNA is double-stranded as indicated by (i) the sharp increase in extinction coefficient over a narrow range of temperature increase, (ii) an increase in density in CsCl upon thermal denaturation, and (iii) the equivalence of guanine and cytosine as well as adenine and thymine, determined by chemical analysis. phiCbK DNA cosediments with Escherichia coli phage T2 DNA and has therefore been assigned an S(20,w) value of 63.5S. The size of the phage and its DNA and the percentage of DNA indicate that the phiCbK phage head is relatively loosely packed. The properties of the DNA from bacteriophage phiCbK are similar to those of host C. crescentus DNA with respect to buoyant density, thermal transition point, and guanine plus cytosine content.
对新月柄杆菌噬菌体phiCbK及其脱氧核糖核酸（DNA）的物理和化学性质进行了研究。电子显微镜照片显示，该噬菌体是已报道的最大的DNA噬菌体之一，头部尺寸为64×195纳米，有一条275纳米长的柔性尾部。该噬菌体由57%的DNA组成。这种DNA是双链的，这由以下几点表明：（i）在温度升高的狭窄范围内消光系数急剧增加；（ii）热变性后在氯化铯中的密度增加；（iii）通过化学分析确定鸟嘌呤与胞嘧啶以及腺嘌呤与胸腺嘧啶的当量。phiCbK DNA与大肠杆菌噬菌体T2 DNA共沉降，因此被赋予了63.5S的S(20,w)值。噬菌体及其DNA的大小以及DNA的百分比表明，phiCbK噬菌体头部的包装相对松散。噬菌体phiCbK的DNA在浮力密度、热转变点和鸟嘌呤加胞嘧啶含量方面与宿主新月柄杆菌DNA的性质相似。
