Test 2 Micro (Ppts 1-2)
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Ability of bacteria to move into normally sterile tissue sites.
Ability of bacteria to cause disease
A measure of pathogenicity
Bacterial products that allow the bacteria to damage the host and cause disease
3 domains of life?
Which one contains the nonmicrobes?
- Bacteria, Eukarya, Arachae
- Non-microbes are eukarya (obviously...think plants, etc.)
Membrane lipids of archaea are linked by?
Ether bonds (Bacteria and Eukarya have ester-linked)
Which domains have:
1) 80S ribosome?
2) Internal membranous organelles?
3) Poycistronic mRNA?
4) mRNA editing?
5) Muramic acid in cell wall?
- 1) Eukarya
- 2) Eukarya
- 3) Bacteria, Archaea
- 4) Eukarya
- 5) Bacteria
- 1) Fix bacteria to microscope
- 2) Crystal violet
- 3) Gram's iodine (mordant)
- 4) Decolorize (alcohol or acetone)
- 5) Safranin Red
Which bacteria are the only ones that have sterols in their cytoplasmic membrane? How do they get them? Why do they need them?
They are more resistant to?
Mycoplasma have sterols in the cytoplasmic membrane. They lack a cell wall so they steal sterols from host to strengthen their membrane.
Mycoplasma are more resistant to disinfectants and drying.
- Cell wall or PPG
- Composed of glycan strands and peptide cross-links
Stem peptide for PPG unit?
NAM (N-acetylmuramic acid)
How does lysozyme disintegrate the cell wall?
Cleaves the B-1,4 cross-link between NAG and NAM
UDP-NAM-PEP (after D-ala-D-ala is added)
D-ala-D-ala dipeptide is added together in the last step of UDP-NAM polymerization. Do these steps require ATP?
Bactoprenol Phosphate (C55)
Lipid carrer in the cytoplasmic membrane
These are also known as?
- Transglycosylases connect the dissacharides
- Transpeptidases connect the stem peptides
- Penicillin-Binding Proteins (PBPs)
UDP- NAG forms
UDP-NAM (look at slide 20)
D-ala-D-ala terminus of stem peptides.
When PBPs bind Beta-lactams, they are acylated in their Ser active site and irreversibly inactivated.
Glycopeptides are used to treat? (G-P or G-N)
How do they work?
- Glycopeptides are used to treat G-Positives (Act on cell wall and can't penetrate outer membrane of G-Negatives).
- Bind the D-ala-D-ala terminus, shut down transpeptidation rxns.
What links the PPG and outer membrane of Gram-Ns?
Used for serological identifcation?
- Endotoxin (represent outer leaflet of outer membrane)
- Lipid A is the toxic component
- "O" antigens used for serological identification
Mutations in the porin genes can change
The permeability of a given porin to an antibiotic, thus conferring some protection for the bacteria
1) Pili inhibit _______
UEPC has two types of pili:
Which one is associated with pylonephritis?
- P-pilus: Binds galactose and glycosphingolipids in ueroepithelial mucosa and renal tissues. Associated w/ pyelonephritis)
- Type 1 pilus: Binds mannose on Uroplakin 1a in the bladder, express in renal tissue
What type of bacteria usually lack flagella?
One flagellum at pole
One tuft of flagella at pole
Flagella at both poles
Flagella all around the cell
- Spirochete flagella that wrap around the cell. Impart screw like motility (eukaryote flagella have whip-like motions).
- Allow bacteria to penetrate viscous material like mucous.
Two bacteria classes that produce spores?
Bacillus and Clostridium
Spore within bacterial cell?
Development of dorman spore into a metabolically active vegetative cell?
- Exosporum (Outer)
- Inner Membrane
- Core (Inner)
Outer layer of spore. Membrane remaining after formation.
- Keratin-like protein w/ S-S bonds
- Impervious to UV and ionizing radiation
Concentric rings of PPG
Which layer of the spore resembles the cytoplasmic membrane?
1) 3 Nutritional Types of Bacteria?
Which one uses organic compounds as its Carbon source?
Which one oxidizes inorganic compounds?
- Hetrotrophic/organotrophic, Photosynthetic, Autotrophic/lithotrophic
- Hetrotrophic oxidzies organic compounds
- Autotrophic oxidizes inorganic compounds
All bacteria causing human disease is thought to be?
Which bacteria require water and nitrogen?
Heterotrophs in certain temperatures:
- 1) -15 to 20 C
- 2) 20 to 45 C
- 3) 45 to 122 C
Mesophiles grow at human body temperature
Hexose (6-C) --> Pyruvate (3-C)
In this process, 2 things happen. What are they?
Problem? What is done about it?
- ADP--> ATP
- NAD reduced to NADH
NAD is limited, but fermentation (pyruvate -> lactate) helps w/ this by oxidizing NADH back to NAD.
What regenerates NAD for substrate level phosphorylation in heterophiles?
Fermentation is the sole means of energy generation for many ____
Streptococcus mutans produces ______ that is responsible for dental caries?
S. mutans in normal flora that causes disease in its usual niche.
This bacteria generates energy only by fermentation and is responsible for the H2 gas in gas gangrene.
Clostridia (e.g. Clostridium perfringens)
Which produces more energy for heterophilic bacteria?
1) Pyruvate entering the TCA/Krebs cycle
2) NADH entering the ETC
- Pyruvate entering the TCA/Krebs = 2 ATP
- NADH entering the ETC = 38 ATP (via Proton Motive Force)
What part of the bacteria has the ETC?
Cytoplasmic membrane pumps
Protons to ____
Which creates an ____
This generates the ____ which is used to do work
- Protons to exteriorWhich creates an H+ voltage gradient
- This generates the PMF which is used to do work
External protons enter the _____ and bind to a _____
Rotor is made up of? What does it do?
Rotation of "y" unit in center induces _______
- External protons enter the alpha unit and bind to a c-ring subunitRotor = c-ring and y unit. It turns and ejects protons internally.
- Rotation of "y" unit in center induces conformational change in catalytic sites
- Causes synthesis of ATP
How many hydrogens are required per revolution of flagella?
Vibrio cholerae uses a flagella driven by what?
Sodium-driven outside of human host, but proton driven during infection
What is the difference btw aerobic and anaerobic respiration?
Oxygen is not the terminal acceptor in anaerobic respiration.
Uses oxygen when it is present, but can grow without it.
Does not grow in presence of oxygen, oxygen can be lethal.
Obligate (strict) anaerobe
Does not use oxygen for growth, but prefers low levels.
Aerotolerant (these species are strictly fermentative)
Can use oxygen for growth, but prefers low levels.
Microaerophiles (low levels= micro levels)
Requires oxygen for growth.
Obligate (strict) aerobe
What 3 enzymes do obligate anaerobes not have?
What do these enzymes do?
- Superoxide Dismutase
These enzymes detoxify oxygen radicals
Streptococci lack ____ and are ____
What differentail medium is used to determine the oxygen relationships of bacteria?
Thioglycolate medium (colorless = anaerobic; green/blue = aerobic = methylene blue)
Tubulin-like protein that assembles as a ring of filaments (Z-ring) at mid-cell
Proteins that ensure the Z-ring forms at mid-cell
- MinCD: Prevents FtsZ from forming at poles
- MinE: Prevents MinCD from forming at mid-cell
Constricts the dividing bacterium -> formation of a septum and separation of daughter cells.
Mutation in what can lead to a "minicell"
Genes encoding the Min proteins (allows Z-ring to form at inappropriate site)
Do bacteria engulf food particles?
How are they transferred across the cell?
No, they are digested externally and tranferred across the cell via Passive Transport System (membrane-spanning, barrel-sshaped components w/ external receptors.) These are present in both membranes of a Gram-N bacteria.
Active transporters include?
- Antiporters and Symporters
- Proline uses a Proline-H Symporter
The witholding of nutrients to prevent bacterial growth?
Iron Acquisition Systems (key bacterial virulence factors):
- 1) Siderophore Systems (low MW iron-chelating complexes secreted by bacteria that have a higher affinity for Fe than transferring, lactoferrin, or ferritin)
- 2) Transferrin & Lactoferrin Receptors
- 3) Heme Acquisition Systems
Host antimicrobial peptide that binds siderophore-iron complexes to prevent internalization.
Which bacterial secretion system is found only in pathogens?
Type III Secretion System
Which bacterial secretion systems are ATP Binding Cassettes ( ABC transporters)?
Type I Secretion Systems (export things to periplasm)
Bacteria regulate their metabolism by two ways:
- 1) Regulate enzyme activity
- 2) Regulate enzyme synthesis
Life in a community (attached to a surface, encased in a matrix)
Stages of Bacterial Growth
Stages of biofilm formation
- Surface attachment
- Development of matrix
Cells in a biofilm are ______ different from planktonic cells.
physiologically (gene expression differs)
What two bacteria form a biofilm infection of prosthetic joints?
Staph aureus and epidermidis
Bacterially secreted peptides that inhibit growth or kill other bacteria, the producing bacteria are immune.
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