Basic Bacteria Genetics and Classification Flashcards
Mutation - base pairs
- Replacement
- Deletion
- Insertion
Mutation - base pairs Effects
- Missense
- Nonsense
- Frame shift
Recombination
GC: Antigenic Variation
- Pili and outer membrane proteins (OMPs) mediate attachment
- Both are antigenic
- In vitro antigenic types change
-Shift is accelerated by antibody to dominant antigenic type
- Different antigenic types have been isolated from the same patient
- GC - takes place during infection
- Many, many more antigenic types
GC: Gene Regulation Opa genetics
Genetic Exchange
Genome segments (genes) exchanged between bacteria
Mechanisms
- Transformation
- Conjugation
- Transduction
Transformation
Transduction
Conjugation
Integrating DNA from Transduction and Conjugation
Transposable elements are genetic units that are capable of mediating their own transfer from one chromosome to another, from one location to another on the same chromosome, or between chromosome and plasmid. This transposition relies on their ability to synthesize their own site-specific recombination enzymes, called transposases. The major kinds of transposable elements are insertion sequence (IS) elements, transposons (Tn), and certain phages. Transposition accomplishes genetic exchange between the chromosome and/or plasmids of the same bacterial cell or its descendants. It does not bring external genetic material as occurs with transformation, transduction, and conjugation
Inssertion Sequences
- Insertion sequence elements are small segments of DNA which encode enzymes for site-specific recombination and have distinctive nucleotide sequences at their termini.
- Only genes involved in transposition are included in IS elements
- If an IS element transposes to a new site within a gene, it alters or destroys the activity of the gene.
Transposons
- Transposons include IS elements PLUS DNA containing genes beyond those needed for transposition
- The additional genes may code for such properties as antimicrobial resistance, substrate metabolism, or other functions.
Specimens
Microscopy
Culture