Bacterial lysogeny (phage conversion) — Which trait(s) are well-known results of lysogenic conversion by bacteriophages?

Introduction / Context:
Lysogenic conversion occurs when a temperate phage integrates into a bacterial genome and brings genes that alter the phenotype of the host bacterium. This can include toxin genes or surface antigen variations, impacting virulence and epidemiology.

Given Data / Assumptions:

• Corynebacterium diphtheriae requires a tox gene from corynephage for diphtheria toxin production.
• Certain Clostridium botulinum strains (types C and D) carry phage-encoded botulinum toxin genes.
• Phase variation, including antigenic shifts in some Salmonella serovars (e.g., anatum), can be influenced by phage elements.

Concept / Approach:
Because each listed trait is a classic example of phage-mediated conversion, the comprehensive answer is “All of the above.” Recognizing phage roles helps explain sudden acquisition of virulence in bacterial populations.

Step-by-Step Solution:

Verification / Alternative check:
Historical and molecular studies document prophage-encoded toxins and antigenic modifications in these bacteria.

Why Other Options Are Wrong:

• Picking a single item ignores the breadth of documented lysogenic conversions.

Common Pitfalls:
Assuming all toxins are chromosomal; many key toxins are phage-borne.

Final Answer:
All of the above