L33 How DNA is transferred between materials

Flashcards covering key vocabulary and concepts from the Microbial Genetics lecture on how DNA is transferred between microbes.

Horizontal Gene Transfer

Transfer of genetic material directly from one organism to another. This is a process specific to bacteria.

Griffiths experiment demonstrating horizontal gene transfer

Streptococcus had S strain (fatal) and R strain (negligable). He heat treated S strain cells which were then negligible (mouse lived). Then he injected mouse with both heat treated S strain and R strain and mouse died. Culture shows living cells with S strain.

Properties of bacterial genome

Single, circular chromosome, nucleoid, and plasmids (self replicating DNA molecules in cytosol)

Vertical Gene Transfer

Transfer of genetic material from parent to offspring.

Virulence Factors

Attributes that help bacteria survive in the host, sometimes at a cost to the host. Eg capsules on streptoccocus pnuemonia.

Antibiotic Resistance

Attributes that reduce the effectiveness of antibiotics against the targeted bacteria. Eg plasmid carrying Beta-lactamase enzyme (inactivates penicillin)

Types of horizontal gene transfer

Transformation, transduction, conjugation.

Transformation

Uptake of short fragments of naked DNA from the environment by naturally transformable bacteria.

Transduction

Transfer of DNA between bacteria via bacteriophages (virus). During assembly of bacteriophage, instead of being filled with its own DNA it takes in plasmids. Then goes on to replicate.

Conjugation

Direct transfer of DNA between live bacterial cells via sexual pilus, requires cell to cell contact. Pilus attaches to other cell, plasmid unwinds and travels across pilus.

Bacteriophages

Viruses that specifically target and kill bacteria; used in phage therapy.

Phage Therapy

The therapeutic use of bacteriophages to treat pathogenic bacterial infections.