Bact Path – Microbiology – Flashcards

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Sec Proteins
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SecB - chaperone
SecA - ATPase
SecYEG - transporter
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SecA Functions (4)
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1. Recruit Protein to SecYEG
2. Provide energy (ATP)
3. Push peptide through
4. Prevent back sliding
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Sec Signal Peptide Structure
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Small (7-15 amino acids)
Basic N terminal
Hydrophobic Middle
SXS Cleavage Site
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SRP "Proteins"
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FtsH - Particle - chaperone (co-translational)
FtsY - Bring to SecYEG

Both have GTP activity
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Topology Rules
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1. Positive Inside
2. IM - alpha helices
3. OM - beta sheets
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Topology Experiment Genes
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PhoA - periplasm
LacZ - cytoplasm

*must be C-termninal
**wont work if too close to the membrane
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TAT Proteins
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TATC - 7TM domain - RR recognition
TATD - cytoplasmic unknown function

All others two helices
TATB - help TATC
TATA - polymerize
TATE - unknown
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TAT energy source
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Proton Motive Force
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Oxidative Pathway vs. Reducing Pathway
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DsbA/B and DsbC/D
Use second to re-estiablish first using the electron transport chain of the IM
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Periplasmic Chaperones
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Skp - OM proteins
Pilus Specific Chaperones
LolA/B - lipoprotiens
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PPI (function and location)
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Peptidyl prolyl isomerase
periplasm (lots of OM proteins have P)
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Periplasmic Proteases
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DegP and DegS
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Sigma E system
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OM stress - Temperature and Alcohol

RseB bind OM protein
Releases RseA
RseA releases SigmaE
SigmaE promotes: degP, reseABC, fpkA)
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CpxA/R system
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Stress - pH and composition
CpxA gets phosphorylated
Relay to CPxR
CpxR induces degP, CpxA/R, dsbA
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BAM
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Beta barrel assembly machine
OM proteins
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Type II Secretion
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Start with Sec/Tat
No Anchor
Secreton: Secretin (ring) and Piston (pilus-like)
Coupled to Cytoplasm for energy (ATP)
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Type V Secretion
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Autotransporters
VacA and IgA1

sec/tat signal, passenger (contains cystines), beta barrel
optional cleavage
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Type I Secretion
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Skip periplasm
HlyA (in E. coli)
Each have their own translocase (substrate specific)
- trimeric IM anchor
- ABC transporter
Pairs with TolC (alpha helices protect)
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Type III Secretion
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And Type 4, 6, 7
Nano Syringe
ATPase at base (cytoplasm)

Vir complex
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Parts of Pap Protein
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PapG - tip
PapF - linker
PapE - fimbrillae
PapK - linker
PapA - rod pili structure
PapH - anchor
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Non-structural Pap Genes
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PapC - usher
PapD - chaperone
PapI and PapB - regulatory
PapJ - unknown
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PapD Mechanism
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Donor Strand Complementation
Ig Fold has 7 Beta sheets
Need G1 of PapD to bing to C-terminal of Pilin
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Driving Force of Type 1 pili
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4 structure
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Regulators of Pilins
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CAP
Lrp (Leucine response regulator protein)
Iron
Temperature
SigmaE/Cpx
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Regulatory mechanisms of pili
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1. Methylation-Dependent (gradient)
2. Inversion-Dependent (on/off)
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Twitching Motility Requirements
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Flagella-independent
Wet Surfaces
Population dependent
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Type IV Pilus Movement Mechanism
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Twitching Motility
Extension, Tether, Retract (pilT-dependent)
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Type IV Pilus Structure
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Pre-pilin: N-alpha helix, 4 beta sheets, adhesion
Pentamers: Coiled-Coil
Glycoslated
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Type IV Pili Genes
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PilE -pilin
PilQ - secretin
PilS - pseudogenes
pilD,F,G,T - energy coupling (secreton)
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Type IV Aseembly
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Homologous to Type II
1. Pre-pilin goes through Sec system
2. Signal Cleaved on cytosolic face
3. Pentamer formation
4. Ogliomerization (DsbA dependent)
5. Secreted by PilQ
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Mechanism of Pilin modification (protein)
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pilS genes without N termini
Combined at random - infinite combinations
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LPS Sugars
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Core
KDO - 8C
Heptose - 7C
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LPS Assay
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LAL Assay
Horseshoe Crab
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McConkey Plates
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Select for Enteric Bacteria due to high bile contents that bacteria need O antigen to withstand
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O antigen Functions
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1. Resistance to Complement
2. Resistance to Bile Salts
3. Resistance to Detergents
4. Phase Variation (homopolymeric tracts on enzyme genes)
5. *We used vaccine*
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LPS Assembly
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1. Core Sugars with nucleotides
2. Assembled of O antigen and LipidA-Core Separately
- O antigen on undecarponal tail
3. Export O (Wzx/Wzy or ABC system)*
4. Expore LipidA-Core (MsbA system)*
5. Add O to LipidA-Core (WaaL system)
6. Transport to OM (Lpt System)*

*ATP is the energy source
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K host mimicry examples
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K1/Niesseria - neural cell adhesion molecule
K5 - heprin
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Functions of Capsule
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1. Invade Serum (complement)
2. Host Mimicry
3. Phase Variation
4. Prevent dessication
5. Adherence
6. Motility (lube)
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Phase Variation of Capsule Example
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C. jejuni
on/off or gradual
population level
CPS gene cluster = homopolymeric tract = slipped strand mutagenesis
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Glycosylation in H. pylori
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Flagella, OM, IM, Cytoplasmic

Just O-linked
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Glycosylation in C. jejuni
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Flagella, Periplasmic

O-linked and N-linked
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O linked glycosylation - Specificity
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Ser/Thr

Structrual (surface)
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N linked glycosylation - specificity
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D/E - X - N - X - S/T

Only last three in euks
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Glycosylation Sugars
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Simple: Heptose (e. coli)
Complex: Pse, DAB (C. pylori)
Polymeric: Trisaccharides (archaea)
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Functions of Glycosylation
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1. Secretion
2. Antigenecity - immunoevasion
3. Stability, solubility, and polymerization
4. Adhesion (invasion of host tissue)
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Glycosylation in N. gonorrheae
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ptgA gene encodes a glycosyl transferase

Complicated strains - polyG tract = not always expressed = migration
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Ogliosaccharide production
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1. assembly of nuc-sugars onto undecaprenol phosphate carrier (Und-P)
2. Black transfer to periplasm
3. saccharidyl transferase attaches sugar to protein
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Ogliosaccharide example
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pgIB in c. pylori N
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Treatment of H. pylori
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Chlarithromycin, Tetracyclin, Protein Pump Inhibitor, Bismuth

High doses - to reach stomach = nasty side-effects
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H. pylori animal models
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WT Mice (and adapted bug) = infection no inflammation
Il-10 KO mice = inflammation but little infection
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H. pylori Virulence Factors (7)
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1. Urease
2. Type 4 Secretion - Cog PI (cancer) *not all strains
3. VacA
4. LPS - Lipid A is poorly endotoxic
5. Lewis structures on OMP and O antigen
6. Flagella - glycosylated
7. Hcps
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VacA
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Autotransporter gene
polymorphisms - paleo-microbiology and differences in virulence
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Hcps
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Heliobacter Cystine-rich Proteins
- SLR motif:helix-SS-helix = protein-protein interaction
- need dsbK
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Regulation of Cytokine Activity (5)
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1. de novo
2. short mRNA halflife
3. Procytokines produced first
4. Short activation radius
5. High affinity receptors
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Myristiltated
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attaching lipids (usually N terminal)
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TACE
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TNF alpha converting factor
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IL-1 Receptors and Antagonists
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IL-RI - normal
IL-RII - no signal transduction
IL-Ra - antigonist
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IL-1 activation
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1. Production of pro-ILB
2. Secondary signal (C3aR or TLR4) - efflux of ATP
3. ATP sensed by p2X7 - ion exchange
4. Caspase-1 activation
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Function of IL-8
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1. Bring neutrphils
2. Neutrophil adherence
3. Neutrophil granular exocytosis
4. Respiratory burst
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CXCR1 Structure and Function
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7 TM - G coupled protein receptor
IL-8 receptor
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CXCR1 alpha pathway
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PLC cuts PIP2 into IP3 and DAG
IP3 - releases Ca2+ stores
DAG - increases NADPH oxidase activity
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CXCR1 beta-gamma pathway
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PI3 Kinase adds p to PIP2 -> PIP3
chemotaxis, adhesion

neutrophil granular exocytosis (by MAPK)
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PLC Effect on Phospholipids and Diacylglycerols
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Make Arachonic Acid
1. Make Leukotrienes
- B4 - neutrophil recruitment and pro-inflammatory

2. Make Prostacyclin
- vasodilation and platelet aggregation

Thromboxane
- platelet activation and vasoconstriction

*All have G-coupled protein receptor pathways
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Neutrophils - Secretory Proteins
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CR1, CR3, FPR, CD14, CD16 (IgG)
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Neutrophil - Developmental stages
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1. Blast cell
2. Promyelocyte
3. Myelocyte
4. PMN
- wait for 5 days
- blood for 10 hours (shorter if used)
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Attachment of Neutrophils and Vasculature in Extravasation
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P-selectin - PSGL
ICAM - LFA1
PECAM-1 homodimers
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Oxygen Dependent Killing
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b558 Cytochrome (NADPH oxidase) => superoxide anion
Superoxide dismutase => hydrogen peroxide
Myeloperoxidase + Halide => HOCl
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Antimicrobial Serprocidins
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(1) Cathepsin G
- gram positives
- peptides are also antimicrobials
- stimulates acute phase response

(2) Elastase
- gram negatives
cuts OM proteins and secreted peptides
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Wegeners Granulomatosis
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Anti-neutrophil cytoplasmic antibodies (ANCA)

loop
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BPI
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binds LPS since its positive
Bacterocidal - binds LPS, disrupts membrane
Immunosuppresion - mop up
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NET
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Neutrophil Extracellular Traps
- DNA and granular proteins
Elastase is kept active (despite being extracellular)
= liver necrosis
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Contact Activation Pathway (coagulation)
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(1) Factor 12 -> Factor 11
(2) Kallikwein -> Factor 11
(3) HMW Kinninogen
(4) Brandykinin
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MacI (Function and Inhibitor)
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Receptor on neutrophil
activated by M protein
inhibited by beta2-integrin
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hemmorhagic skin lesions
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Purpula fulminans
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LBP domains
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BPI-1: binds LPS
- common amoung acute phase proteins
BPI-2: transfer to Cd14
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Mice for LPS Discovery
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C3H/HeJ
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TLR/IL-1 Receptor Pathway
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MyD88->IRAK->TRAK->TAK
(1)NIK-> IKK -> NFKB

(2)MIKK->JNK-> AP-1
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HPA-axis
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Hypothalamus -> CRF
Pituitary Gland -> ACTH
Adrenal Cortex -> Glucocorticoid
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Mif
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Migration inhibitory factor
- produced by adrenal gland
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Role of Protein C
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(1) Thrombin binds Thrombomodulin
(2) Activates protein C
(3) Protein C cleaves Factor 5 and 8
(4) Inhibits coagulation and starts breaking down clot
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APC drug
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Drotrecogin alfa (activated protein c)
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PIC
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Protease involed in colonization
E. coli and shigella
activate PMN but not migration
break PSGL-1 sugar linkages
kill T cells
deleted from shigella - more inflammation
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Anti-microbial peptides
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alpha-defensins
beta defensins
hCAP18 -> IL37

All positive
defensines have Cys
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Beta Defensins (location and organisms)
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hBD1 - negative (GI, reprodu, urine)
hBD3 - positive (oral, skin, respir)
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Systems for recognizing LL-37 (3 organisms)
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CovS/R (Strep) ApsS/R (staph) PhoQ/P (enter)
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Upregulated genes in Strep after Cov system (6)
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1. Hyaluronic acid capsule
2. SpyCep and PrtS - IL-8 proteases
3. Mac/IseL - IgG proteases
4. Streptokinase
5. SpeA
6. DNase
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Upregulated genes in Staph after Aps system (4)
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1. ApsS - membrane integrety
2. VraFG - influx pump
3. dltABC - D-alanine make less negative - techonic lipids
4. mprF - Add positive Lys to phospholipids
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Upregulated genes in Enter bacteria after Pho system (4)
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PagP, PagL, LpxO, pmrAB - Lipid A modification
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mga
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Multipkle gene activator in strep
emm - M protein
C5a protease
inhibitor of complement (sip)
IgG binding protein
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Phage SA3 genes (5)
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extracellular adhesion protein
SAgs
CHIP
Staphlyococcal inhibitor of complement
Staphylokinase
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Scn
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Staphylococcal inhibitor of complement
- binds C3Bb in an inactive binding state (both)
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CHIP
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Chemotaxis inhibitor protein
- produced by staph
- inhibits C5a and fmlp signaling by binding sulfanated Y residues on receptors
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SpyCep
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Cell enevlope protein on Strep
degrades Il-8 and other CXC chemokines
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Pigments
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Staphyloxanthain
Prodigiosin (serratia)
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Fat Transcription Factor
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Ppar-Gamma
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Antimicrobial produced by Fat Cells
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Cathelicidin
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Secreted Anti-microbial Lipids
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Sapienic Acid (Palmitoleic Acid)
Cholesterol Esters: Linoleic Acid and Arachiclonic Acid
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Mass formed by TB
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Granuloma - caseous necrosis
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Drugs for TB
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Isoniazid, Pyrazinamide - Inhibit Fatty Acid Synthesis
Rifampin - RNAP
Ethambutol - Arabinogalactin synthesis
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TB - important cell wall components (3)
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1. Mycolic Acid
2. Arabinan Layer
3.Lipoarabinomannon
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Mycolic Acid Structure
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Trehalose dimycolate
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TDM binding
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Macrophage Scavenger Protein
Macrophage-Inducible C-type Lectin (MINCLE)
- MAC1 expression
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TB dMINCLE Mice
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No immune cells in lung (H and E stain)
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PI Head Group
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D-myoinositol with P = 3, 4, 5
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Phagocytosis
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Fc-IgG
Fc-P
PI3KI -> PI345P3
Rab5 (GTPase) -> PI3KIII
PI3KIII-> PI3P
EEA1
EEA1 delivers hydrolases and H+ ATPase
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Role of Lipoarabinomannon (LAM)
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MBL
EEA1
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PIM
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Precurser to LAM
Promotes homotypic fusion - feeding from endosomes
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TB - Proteases
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SapM - deP PIP3 PtpA - no ATPase PtpB - Il-6, Caspase 1
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TB - Esx-1
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Type IV secretion

EsxA (ESAT6) -> lysis, phagosome rearrangement
EsxB (CFP10) -> phagosome rearrangement

eDNA
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Listeria - entry
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Zipper
E-Cadherin (Ca2)
basolaterial face

blocked by b2-integrin

uses internalins
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Listeria - internalins (classes, structure)
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(1) LPXTG - InA
(2) GW - InB
(3) LXW

Look like TLR
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Mouse E-Cadherin
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Has Glu-16 not P-16
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Saprophytic
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Extracellular Listeria
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Listeria - riboswitch (name and genes -5)
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Ptg

1. hly - pore
2. plcA/B - break phagosome
3. mpl - help plcB
4. actA - movement
5. hpt - hexose phosphate transfer
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Listeria - movement
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ActA
localizes pole

1. Actin
2. Arp2/3
3. WASP-homology domain
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Salmonella PI secretion type
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III
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Salmonella entry genes
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SipC -> actin nucleation, bundling
SipA -> helps
SopE/E2 -> GEF for Rac CDC42 (can recruit Arp2/3 for branches)
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Salmonella Il-8/inflammation factors
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SopE/E2 -> GEF also promotes MAPK signaling
SipB -> Activates Caspase 1
SopB -> Inositol phosphatase - activates Rho and Cdc42, secretion of Cl-, disrupt tight junctions
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SaPI - 2: genes for microtubules
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SspH2, SpvB, SseI -> actin nest
SifA, PipB2 -> Sif formation
SseF, SseG -> promotes budding and collecting vesicles from golgi
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Salmonella - inhibition of death
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SseK
glucosylatea FADD, TRADD, RIPK1
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