Bailey 1 Flashcards
oligotrophs
grow with limited nutrients
microaerophiles
require some oxygen, but lower levels
Mesophiles
grow well in mild temps
Envelope of gram +
Inner:
---Cell membrane
---Thick cell wall made of:
*Murein
*Techoic/lipotechoic acid
OuterEnvelope of gram -
Inner:
---Inner membrane
---Periplasm
---Thin cell wall made of:
*Murein
*Lipoprotein
---Outer membrane w/ LPS
OuterStructure of Murein
NAG and NAM
Crosslinks b/w NAM
Gram + Murein cross link composition
L-Lys-(gly)5-D-ala
Gram - Murein cross link composition
DAP-D-ala
Biosynthesis of murein
Murein made in cytoplasm
Cross linked in perisplasm
Structure of LPS
Lipid A -Phosphorylated disaccharide w/ FA chains Polysaccharide core Repeating O antigen -Reason for difference
LPS aka endotoxin induces what cytokine? And can lead to what illness?
TNF-alpha
Septic shock
What recognize PAMPs?
PRRs like TLRs
TLR-4 recognizes what?
LPS
TLR-2 recognizes what?
Peptidoglycan (PG)
TLR-2 +6 recognizes what?
Teichoic acid
Fimbriae vs flagella
Fimbriae used for attachment
Flagella for motility
Adhesins
Specialized proteins that are designed specifically for adherence. Located on tips of pili
Monotrichous
Lophotrichous
Peritrichous
Monotrichous-One flagella
Lophotrichous-Multiple flagella in localized area
Peritrichous-many flagella all over
Directed movement referred to as
taxis
May be toward something good or away from bad stimulus
Glycocalyx
A substance that surrounds a cell
Capsule definition and composition
Well organized glycocalyx that is firmly attached
-Made of polysaccharides, but can include monosaccharides and glycoproteins.
Slime layer
Loosely attached glycocalyx
Why is a capsule so important
Crucial virulence factor for some.
TLR-5 recognizes what?
Flagella
Sometimes capsular polysaccharide can be recognized too?
How are bacteria named based on serological designations?
O antigen-has LPS (G-)
H antigen-flagella
K-capsule
# after each letter refers to what number discovered
Opportunistic pathogens
Rarely cause disease in those w/ intact immunological defenses
Many are normally found on the body (S. Aureus)
Primary pathogens
Can establish infection and cause disease in individuals w/ intact immune defenses
Before a pathogen can colonize or invade it must _____
adhere
Types of adherence
Nonspecific adherence
Specific adherence
Nonspecific adherence
- reversible
- docking
- Random interactions
Specific adherence
- irreversible
- anchoring
- Involves fimbrae and adhesins
- May be found on capsules or cell surface
How does strep mutans bind
Binds to tooth pellicle
Adhesin is glucosyl transferase. It binds to salivary protein involved in pellicle formation
Are all adhesins found on pili?
No. Can be found on cell surfaces too.
Bacteria may bind what substance at their surface
Fibronectin
- May occur due to lipotechoic acids that bind to fibronectin
- Surface proteins will bind fibronectin too
How do bacteria take up nutrients
Facilitated
Group translocation (phosphorylation linked transport)
Active transport
How are colonization and pathogenesis related?
Colonization alone is not enough for pathogenesis
Endotoxin
Not secreted. On the surface of bacteria
LPS is most common
Exotoxin
Classified by three types:
1) Type 1-Membrane acting-toxins bind to surface receptors and stimulate transmembrane signals
2) Type 2-Membrane damaging
3) Type 3-Intracellular effectors-get into the cell and induce enzymatic activity
What makes a microbe a pathogen
- Adhere to host
- Colonize the host
- Replicate w/in given niche
- Cause damage
- Invasion
- Toxin
- Activate immune sys
