Exam 2 Review Flashcards
Colonization factors for pseudomonas
Pili and adhesins
Survival factors for pseudomonas
LPS, capsule and biofilm formation
Factors that cause damage or spread
LPS and toxins, flagella motility and chemotaxis
Regulatory factors
Sigma factors (algU), two component regulation, quorum sensing
Two- component regulatory system
Senses chemokine, histidine kinase self phosphorylates, transfers to response regulator, controls flagellar rotation
Alginate
A protective capsule secreted by P. Aeruginosa , protects against host defenses and antibiotics
AlgU
Sigma factor that controls alginate production, usually sequestered by MucA, but freed by periplasmic protease
MucA
Membrane protein that sequesters AlgU, cleaved by protease
Biofilm formation steps
- Attachment (Fla+, Pol+)
- Stable binding, growth (Fla-, Pil-)
3-4. Capsule synthesis (Alg+) - Ready for release (Fla+, Pil+)
- Planktonic bacteria (motility and chemotaxis)
Quorum sensing
Release of autoinducers to give bacteria an idea of what’s there
6 main antibiotic targets
- Cell wall synthesis
- DNA replication
- RNA synthesis
- Protein synthesis
- Folic acid synthesis
- Membrane disruption
Penicillin and vancomycin
Target cell wall synthesis (D-ala D-ala motif)
Fluoroquinlones
Target DNA synthesis
Rifamycin
Targets RNA synthesis (RNA pol)
Tetracyclines, chloramphenicol
Targets protein synthesis
Sulfonamides
Target folic acid synthesis
Daptomycin
Gram positive membrane disruption
Colistin
Gram negative membrane disruption
Ways bacteria resist abx (5)
- Inactivating abx
- Modifying or replacing target
- Remove abx from cell (effluent pumps)
- Prevent uptake
- Develop persister populations
Examples of horizontal gene transfer (3)
Transformation’
- Transduction
- Conjugation
Plasmid
Self replicating circular DNA that can move between cells
Transposons
Linear DNA that can move within a cell
Phages
Viruses that attack bacteria
Examples of mobile genetic elements (3)
- Plasmid
- Transposons
- Phages
Transformation
Process by which competent bacteria acquires genes from environment, sensitive to DNAse, small pieces
Transduction
When a phage carries a piece of DNA to another bacterial cell (generalized lytic or specific lysogenic)
RecA
Protein that catalyze homologous recombination events
Replicons
DNA elements capable of self replication (bacterial chromosomes and plasmids)
Rep protein
Recruit DNA pol to initiate DNA replication
Origin of replication (Ori)
Binding site on DNA for REP
OriC- chromosome
-OriV- Vegetative plasmid
- OriR- R factor plasmid
Tra operon
Set of genes that encode for the transfer apparatus the sex pilus, can be anywhere in cell
oriT
Origin of transfer, must be on replicons to be transferred
COnjugation
A process by which the transfer of genetic arterial from one bacterium to another through direct contact
Transposase
Needed for a region to be Transposon
IR
Inverse repeat, at each end of a transposon
How do viruses produce multiple proteins (5)
- Segmented genome
- Polyprotein
-Nested mRNA
Start and stop transcription - Alternative splicing
Antigenic shift
Cell with multiple different viruses, genomes differently packaged
Antigenic drift
Mutations arise. Leading to loss or gain of function
