Dobritsa A P, Mikhaĭlov A A, Zarubina A P, Zharikova G G, Vaniushin B F
Mol Biol (Mosk). 1975 Jul-Aug;9(4):602-8.
The 1 P+f phage, a virulent mutant of the moderate P+ phage for Bac. brevis var. G.-B., consists of a hexagonal head (90x90 nm) and a long non-contractile tail (340 nm). This phage is characterized by a relatively long latent period (90-110 min) and a low yield (40-50 particles per cell). The 1P+f phage is quite stable at pH values from 1 to 11, insensitive to osmotic shock, treatment with chloroform and acridine orange. The sensitivity of the phage to thermal treatment and UV-radiation has been studied. The nucleic acid of the P+f phage is double-stranded DNA of AT-type (GC equals 34.5 mole %) which contains 5-methylcytosine (0.18 mole %) and N6-methyladenine (0.32 mole%). The level of methylation of cytosine and adenine residues in DNA of the 1 P+f phage does not depend on the host studied (Bac. brevis, P- and S variants). The specificity of methylation of cytosine residues in the S and P- cells appears to be the same. DNA of the 1 P+f phage strongly differs from DNA of the host in nucleotide composition (GC equals 45.7 mole %). Nevertheless, phage DNA is very similar to DNA from Bac. subtilis in the character of pyrimidine distribution (the amount of different pyrimidine isopliths). This may testify to a somewhat common character of the nucleotide sequence organization in DNA of the phage and its host.
1P+f噬菌体是短芽孢杆菌变种G.-B.的温和P+噬菌体的一种烈性突变体，由一个六边形头部（90×90纳米）和一条长的非收缩性尾部（340纳米）组成。该噬菌体的特征在于潜伏期相对较长（90 - 110分钟）且产量较低（每个细胞产生40 - 50个粒子）。1P+f噬菌体在pH值为1至11时相当稳定，对渗透压休克、氯仿和吖啶橙处理不敏感。已经研究了该噬菌体对热处理和紫外线辐射的敏感性。P+f噬菌体的核酸是AT型双链DNA（GC含量为34.5摩尔%），其中含有5 - 甲基胞嘧啶（0.18摩尔%）和N6 - 甲基腺嘌呤（0.32摩尔%）。1P+f噬菌体DNA中胞嘧啶和腺嘌呤残基的甲基化水平不依赖于所研究的宿主（短芽孢杆菌、P - 和S变种）。S细胞和P - 细胞中胞嘧啶残基的甲基化特异性似乎相同。1P+f噬菌体的DNA在核苷酸组成上与宿主DNA有很大差异（GC含量为45.7摩尔%）。然而，噬菌体DNA在嘧啶分布特征（不同嘧啶等摩尔数的量）上与枯草芽孢杆菌的DNA非常相似。这可能证明了噬菌体及其宿主DNA中核苷酸序列组织有某种共同特征。
