Genetics and Drug resistance Flashcards
Plasmid-mediated Drug Resistance
Genes on Plasmid code for enzymes that modify the drug
Agents modifying proteins
Use on Naked capsid viruses
- Chlorine
- Iodine and iodophors
- Hydrogen peroxide
- Heavy metals (silver and mercury)
- Ethylene oxide
- Formaldehyde
Generalized transducting phage
- When the phage with a lytic life cycle puts a piece of bacterial DNA into its head
- All bacterial genes have an equal chance of being transduced
Ab that undergo Plasmid-Mediated Mechanism of resistance
- Penicillin and cephalosporins
- AG
- Chloramphenicol
- Tetracyclines
- Sulfonamides
- Vanco
Three major roles of Site-Specifc integration
- Integration of Fertility factor to make an Hfr cell
- Integration of temperate phage DNA to create prophage
- Movement and insertion of transposons
What stabalizes bacterial DNA
Homologous recombination
Penicillin/cephalosporin mechanism of resistance
Plasmid-Mediated
Production of β-lactamase
Enzymes required for Homolgous Recombination
- recA
- recB
- recC
- recD
Site-Specific Recombination
Is integration of one DNA molecule into another DNA molecule with which it has no homology
What controls Conjugation
Fertility factor in plasmid or episome
Chloramphenicol mechanism of resistance
- Plasmid-mediated
- Production of acetyltransferases leading to inactivation of drug by acetylation
Transposons are
- Mobile genetic elements that can move themselves or a copy from one molecule of DNA to another
- Have sequences of indirect repeats of bases
- Creat additional mutations with their insertion
- Insertion creats direct repeats
Transformation
Naked DNA is taken up by the cell
Endonucleases
Cleave the nucleic acid backbone in the middle of the NA strand
Aminoglycosides mechanism of resistance
- Plasmid-mediated
- Production of acetyltrasferases, adenosyltransferase, or phosphotransferase that inactivage the drug via acetylation, adenosylation, or phosphorylation
Intrinsic Drug Resistance
- Lack the target molecule for the drug
- Normal anatomy and physiology of bacteria makes them refractory to the drug action
Autoclaving control
15 lbs pressure at 121oC for 15-20 min
Chromosome-mediated Ab resistance
Genes on bacterial chromosome that modify the receptor for a drug so that the drug can no longer bind
Site-Specific Recombination requires
Restriction endonucleases
Agents damaging membranes
Use on Viruses
- Detergents
- Alcohols
- Phenols
Conjugation
Cell to cell contact
Transduction
Bacteriophage pick up and carry bacterial DNA
Natrual transforming bacteria
- H. influenzai
- S. pneumoniae
- Bacillus
- Neisseria
Exonucleases
Remove terminal nucleotides sequentially from linear pieces of DNA
COBEDS
Phage-Coded pathogenic Factors via Lysogenic Conversion
- Cholera toxin
- O antigen of Salmonella
- Botulinum toxin
- Erthrogenic exotoxins of S. pyogenes
- Diptheria toxin
- Shiga toxin
Specialized transduction
- Error is made in the life cycle of a templage (lysogenic) phage
- Temerate phage introduce their genomic DNA into the bacterial chromosome at a specific site
