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Helicobacter pylori utilizes a cag Pathogenicity island. What does that encode for?
A Type IV secretion system
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Salmonella enterica utilizes a SPI-2 pathogenicity island. What does that encode for?
A type III secretion system
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Yersinia enterocolitica utilizes a HPI Pathogenicity island. What does that encode for?
Iron uptake system (siderophore)
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Staphlococcus aureus utilizes a vSa1 pathogenicity island. What does that encode for?
Enterotoxins (superantigens) and lipoproteins
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What is the difference between oriV and oriC?
- oriV is the replication origin for a plasmid
- oriC is the replication origin for a chromosom
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What are the enzymes required for bacterial DNA replication?
- Helicase (unwind)
- Primase (start process)
- Polymerase (synthesize copy)
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Which direction is the leading strand synthesized in?
5’ to 3’
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What is the target of quinolone antibiotics?
Topoisomerase, which normally functions to relieve supercoiling
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What is the target of rifampin?
RNA polymerase
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What is a sigma factor?
Component of RNA polymerase that recognizes different promoters and can coordinate transcription of multiple operons
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What antibiotic classes target the bacterial ribosome complex?
Macrolides, lincosamides, tetracyclines, aminoglycosides, and oxazolidinones
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What is the difference between negative and positive control?
- Negative control = genes are always expressed unless repressor protein is bound to operator
- Positive control = genes are not transcribed unless regulator protein is present
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What type of control (negative or positive) governs the penicillinase production by penicillin resistant bacteria?
Negative control, blaI is normally produced to bind to the operator region and halt transcription. If penicillin is present it binds to BlaR1 which sends BlaR2 to remove BlaI which causes the production of blaZ which results in the production of beta lactamase
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What are the two components of the Accessory gene regulator ( agr) of staphylococci and what is the purpose of the agr?
- TCS and QS
- Facilitates switch from adhesive to invasive state
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What type of mutation happens with Cytosine deamination?
- Cytosine deaminates to uracil
- Uracil pairs with adenine during DNA replication
- When DNA replicates again adenine pairs with thymine
- End result is a C to T mutation
- This sort of thing can be repaired by uracil DNA glycosylase
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What type of mutation happens with deamination of methylated Cytosine?
- Methylated cytosine is deaminated to Thymine
- Thymine is normal, so it is not repaired
- End result is a C to T mutation
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What is more common, transitions or transversions?
Transitions are 10x more common
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What are the three stop codons for bacteria?
TAA, TAG, TGA
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What mutation is associated with antibiotic resistance in MDR-TB?
- katG codon 315
- decreases activation of INH
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