Lecture Notes: Transduction in Bacteria

Overview of Transduction

Definition: Transduction is the process by which a virus transfers DNA from one bacterial cell to another.
Types of DNA Transferred: It involves bacterial DNA, not the viral DNA.
Textbook Reference: Consistent with OpenStax textbook coverage.

Mechanism: Random fragments of bacterial DNA are mistakenly packaged into a phage during its assembly.
- When this phage infects another bacterium, it transfers bacterial DNA instead of viral DNA.
Outcome:
- Typically, the transferred DNA may have no effect and can be degraded.
- Occasionally, it includes beneficial genes, e.g., antibiotic resistance genes.
Frequency: Rare events but are significant due to the high number of bacteria and phages.

Requires Understanding of Phage Cycles:
- Lytic Cycle: Normal cycle where phages infect, replicate, and lyse the host cell.
- Lysogenic Cycle: Phage DNA incorporates into the host genome as a prophage.
  - The prophage remains dormant and replicates with the host DNA until triggered to enter the lytic cycle.
Mechanism:
- Involves temperate phages with potential lysogenic cycles.
- Mistakes during the excision of prophage DNA can result in the inclusion of specific host DNA fragments.
Significance: Increases genetic variability by transferring specific bacterial DNA sections.

Prophage Definition: Viral genetic material incorporated into the bacterial genome.
Impact on Bacterial Virulence:
- Many virulence factors are linked to prophage DNA.
- Examples:
  - Diphtheria toxin
  - Botulinum toxin
  - Cholera toxin
  - Virulence factors in Streptococcus pyogenes
Current Implications:
- Increase in virulence and infections like necrotizing fasciitis.
- Documented rise in such events over the past decade.

Questions and Clarifications: Reach out via Canvas inbox for queries on transduction, conjugation, and mutation.

This lecture aims to align closely with textbook material for consistency and thorough understanding.