Lysis

Abstract

Lysis, that is the dissolution of the bacterial cell, is the essential phenomenon whereby the presence of phage is detected. Some filamentous phages simply leak out of the cell over a period without killing it; certain defective phages multiply in the infected cell but cannot lyse it; some phages termed ‘temperate’ may integrate themselves into the bacterial cell and lyse it only when induced to do so by special treatments. In such cases phage is detected only with difficulty and if all bacteriophages behaved in any one or other of these ways they might not yet have been discovered. Fortunately the virulent, lytic phages are very common. They lyse the cell in which they have multiplied by causing the production within it of an enzyme, lysozyme, that attacks the murein of the cell wall, weakening it so that it bursts and liberates the phage within. In some cases the dissolution of the wall is very nearly complete, in others a substantial amount of debris remains. Lysis can be detected in several ways.