Vegetative Bacteriophage and the Maturation of the Virus Particles

Abstract

Publisher Summary This chapter discusses the vegetative bacteriophage and the maturation of the virus particles and the contribution made by electron microscopy. The direct method of studying phage growth involves kinetic experiments by counting particles, by measuring chemical substances, and similar procedures. However, an indirect approach using radiobiological methods has been developed, as in the Luria–Latarjet type of experiment. After phage adsorbs onto bacteria, the bulk of the phage protein remains outside the cell. The entire DNA is injected along with some minor components of protein-like nature amounting to less than 10% of the total protein content of the phage. This fact, together with other evidence, makes it quite certain that the DNA is the carrier of genetic information. DNA extracted from phage T2 has been the object of many physicochemical investigations, which lead to the assumption that it is made up of two parts. One fraction, involving a single piece of DNA, represents about 40% of the total amount while the rest consists of several much smaller pieces. Nuclear breakdown, which has been observed as only for T-even and T5 phages, is a typical representative of an early phage function, and, because T2 ghosts do not produce it, it is very probably dependent on a partial injection of phage-head material.