Abedon S T
Department of Microbiology and Immunology, Arizona Health Sciences Center, University of Arizona, Tucson 85724.
J Bacteriol. 1992 Dec;174(24):8073-80. doi: 10.1128/jb.174.24.8073-8080.1992.
T4 bacteriophage (phage)-infected cells show a marked increase in latent-period length, called lysis inhibition, upon adsorption of additional T4 phages (secondary adsorption). Lysis inhibition is a complex phenotype requiring the activity of at least six T4 genes. Two basic mysteries surround our understanding of the expression of lysis inhibition: (i) the mechanism of initiation (i.e., how secondary adsorption leads to the expression of lysis inhibition) and (ii) the mechanism of lysis (i.e., how this signal not to lyse is reversed). This study first covers the basic biology of the expression of lysis inhibition and lysis of T4-infected cells at high culture densities. Then evidence is presented which implies that, as with the initiation of lysis inhibition, sudden, lysis-associated clearing of these cultures is likely caused by T4 secondary adsorption. For example, such clearing is often observed for lysis-inhibited T4-infected cells grown in batch culture during T4 stock preparation. The significance of this secondary adsorption-induced lysis to wild T4 populations is discussed. The study concludes with a logical argument suggesting that the lytic nature of the T4 phage particle evolved as a novel mechanism of phage-induced lysis.
T4噬菌体感染的细胞在吸附额外的T4噬菌体（二次吸附）后，潜伏期长度显著增加，这被称为裂解抑制。裂解抑制是一种复杂的表型，至少需要六个T4基因的活性。围绕我们对裂解抑制表达的理解存在两个基本谜团：（i）起始机制（即二次吸附如何导致裂解抑制的表达）和（ii）裂解机制（即不裂解的信号如何被逆转）。本研究首先阐述了在高培养密度下T4感染细胞中裂解抑制表达和裂解的基本生物学过程。然后给出的证据表明，与裂解抑制的起始一样，这些培养物的突然的、与裂解相关的清除可能是由T4二次吸附引起的。例如，在T4储备液制备过程中，分批培养的受裂解抑制的T4感染细胞经常会出现这种清除现象。讨论了这种二次吸附诱导的裂解对野生T4群体的意义。该研究最后进行了一个合乎逻辑的论证，表明T4噬菌体颗粒的裂解性质是作为噬菌体诱导裂解的一种新机制进化而来的。
