Bacteriophage Ecology Group

Bacteriophage Ecology Group Bacteriophage Ecology Group



A bacterium that contains an un-induced prophage.

Prophages often but not always are integrated (inserted) into the bacterial chromosome, and if not then they exist as plasmids within the host bacterium. The phages can exist in this state indefinitely, but also can display productive infections upon induction. Alternatively, lysogens can become spontaneously become cured of one or more prophages.

The word lysogen is derived from the concept of lysis generating, where a bacterial culture, when added to a second bacterial culture, is able to induce the lysis of this second bacterial culture. True lysogens are not curable of this characteristic upon propagation within the presence of anti-phage serum.

By contrast, certain phage-bacterial interactions can exist – described as pseudolysogenic or a phage carrier state – in which lysis generating characteristics in fact may be readily cured in the course of bacterial propagation in the presence of specific anti-phage serum.

This is the definition from Adams (1959), p. 440, for "Lysogenic bacterium": "A bacterium capable of multiplying indefinitely in the infected condition. In lysogenic cultures phage is produced only by exceptional cells that lyse."


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