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transformation
- - taking up DNA from the environment that requires "competence"
- - G+: Strep, Bacillus cereus (quorum sensing)
- - G-: Nisseria, Haemophilus, Helicobacter (starvation)
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Quorum sensing
- - sensing numbers of bacteria
- - can be used for competence induction
-
transductions
- - DNA transfer mediated by bactriophages
- - host range is determined by adhesins (eg tail fiber) and host cell receptors
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conjugation
- transfer of DNA from an F+ to and F- bacteria via T4SS
- conjugative transposons carry tra operon (transfer genes)
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transposition
- - stretches of DNA that can jump to different locations in the genome
- - can even jump onto plasmids resulting in DNA transfer
-
generalized transduction
- - fragment of host DNA is accidently packaged in phage instead of phage DNA
- - lytic lifecycle
- - phage injects DNA into recipient cell, so recipient cell is tranduced, but NOT infected
- ** low success rate**
-
specialized transduction
- - prophage excises incorrectly, taking a piece of host chr along with it (in addition to phage DNA)
- - lysogenic life cycle
- - may transfer complete host genes when phage infects next recipient
- -** high success rate**
-
A-B toxin
- intracellular exotoxin
- A= active domain- has toxic enzymatic activity
- B= binding domain- aims A, binds host receptor, induce endocytosis
- injected into host via T3SS (sometimes T4SS)
-
structural toxin
- component of bacterial cell wall
- LPS/LOS (G-)->LBP+LPS:TL-4
- PG (G+,AcF), lipoteichoic acid (G+,AcF)->bind TLR-2,6
- deleterious effects caused by host IR
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Some bacteria that need capsule for virulence-8
- H. influenza K. pheumoniae
- N. meningitidis E. coli
- S. pyogenes B. anthracis
- S. typhi C. neoformans
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alginate
- aka- mucoid polysaccharide, part of biofilm
- initially CF isolates are non-mucoid
- once mucoid, they get aggressive
- protects against cellular and humoral immunity
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anaerobes of the colon
- Bacteroides spp.
- Clostridium spp
- Fusobasterium spp
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anaerobes of the vagina
- Prevotella
- Bacteroides
- Fusibacterium
- Clostridium
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anaerobes of the mouth
Prevotella, Porohymonas, Bacteroides, Fusibacterium, Actinomyces
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