Question

Which statement is not true for Pseudolysogeny?

• A. Pseudolusogeny is also known as a phage carrier state
• B. Pseudolysogeny occurs when a bacterial culture carries a temperate phage while maintaining an active population.
• C. Pseudolysogeny occurs when a bacterial culture carries a lytic phage while maintaining an active population.
• D. Repeated culture purification helps in eliminating phages from a pseudolysogenenous culture.

Hint:

Lysogeny involves temperate phages (stable integration). Pseudolysogeny is a "phage carrier state" where a lytic phage coexists with a starved host cell without immediately lysing it.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pseudolysogeny is a temporary, unstable state of bacteriophage infection that occurs when a bacterial host cell is under severe nutrient limitation or physiological stress.
In this state, the phage genome enters the cell but remains dormant without integrating into the host chromosome or immediately initiating a lytic cycle.
This condition is also referred to as the phage carrier state, where the bacterial culture carries the phage while maintaining an active, growing population.

Step 2: Detailed Explanation:
Crucially, pseudolysogeny typically occurs with lytic (virulent) phages, rather than temperate phages.
When the host cells are restored to optimal growth conditions, the phage can resume its lytic cycle, leading to cell lysis.
Repeated culture transfers and purification under high-nutrient conditions are commonly used in the dairy industry to eliminate these phages and cure starter cultures.
True lysogeny, by contrast, is a stable association specifically involving temperate phages that integrate their DNA into the host genome.
Therefore, the statement claiming pseudolysogeny involves temperate phages is false.

Step 3: Final Answer
Statement B is not true because pseudolysogeny is associated with lytic phages under starvation conditions, not temperate phages.