Transduction

Question 1

Transduction Basics 101

Answer 1

-form of gene transfer mediated by bacterial viruses (BACTERIOPHAGES aka PHAGE)

Question 2

Transduction 1-Tell me more bout these (BACTERIO)PHAGE characters

Answer 2

-OBLIGATE PARASITES-reproduce ONLY within bacterial cells
-minimally composed of protein and nucleic acid
-individual phage or VIRION consists of a i. PROTEIN CAPSID (protects genomic info from nucleases and detergents) enclosing a ii. GENOMIC NUCLEIC ACID.
(nucleid acid: RNA OR DNA but notttt bothhh)

Question 3

Transduction 2-Clinical Relevance

Answer 3

-bacterial phage can carry genes that arent required for phage propagation
-Corynebacteria diptheria (pathogen…Beta-phage…Beta-toxin) causes diptheria
-Vibrio Cholerae (pathogen…CTX phage…cholera toxin) causes cholera
HOWWWW
-to get toxic effects the host bacterium must be infected by a phage
-Phage carries a gene(S) that encode(S) a toxin
-INFECTED cells are VIRULENT. NONinfected are A-virulent

Question 4

Transduction 3-Bacteriophage Lifestyle Choices (A)

Answer 4

LYTIC (virulent)
(push plunger down, plunge head closer to surface)
-phage genome replicates itself
-proteins synthesized and assembled into capsids
-replicated genomes packaged within the capsids
-phage lyses the host cell
-releases progeny phage into environment
-START from the BEGINNING

Question 5

Transduction 4-Bacteriophage Lifestyle Choices (B)

Answer 5

LYSOGENIC
2 main options: lytic growth OR quiescent PROphage form
-phage becomes LATENT, passed harmlessly onto descendants
-DOES NOT replicate
-phage genome=PROphage
2 ways to become LATENT:
-can circularize as an autonomously replicating plasmid OR physically integrate into the host chromosome
-LYSOGEN=cell that carries prophage, CAPABLE of becoming LYTIC

-VERY stable process, can stay like this for generations, want to propagate under stress

Question 6

Transduction 5-Phage Infection

Answer 6

Step 1: phage infects sensitive cell by ADSORBING (binding) to a specific receptor on that cells surface
Step 2: INJECTING its genome into cell interior
TWO phage types named by fate o phage genome
1. lytic
2. temperate
-Ex C. diptheria beta-phage and V. cholerae CTX phage)

Question 7

Transduction 6-More Phage Business

Answer 7

1. both kinds of transduction occur in BOTH G+ and G- bacteria
2. No cell-to-cell contact required
3. Phage are INDEPENDENT and can “travel” long distances
4. Phage capsids protect DNA…transduction is RESISTANT to nucleases and detergents that interfere with transformation
5. Limited to their own species. Limited cross-species DNA exchange