Germ Theory of Disease

Disporved Spontaneous Generation with Swan-neck flask

Fermentation, vaccines, pasteurization, and sterilzation

Proved Germ Theory

Koch's Postulates

Postulate 1 – identify the suspect
The suspected organism should be present in
ALL cases of the disease and ABSENT from
healthy animals

Postulate 2 – obtain pure culture
The suspected organism should be grown in
PURE CULTURE

Postulate 3 – reproduce the disease
Cells from a pure culture of the suspected
organism should CAUSE DISEASE in a
healthy animal

Postulate 4 – recover the suspect
The suspected organism should be
REISOLATED and shown to be the same as
the original

-no organelles

-Dna not membrane bound

-very small, =mitochondrion is eukaryotes .5um

-cell wall, nucleiod, free ribosomes, cell envelope, storage granules

-single loop of DNA, Domain is one arm of loop, 4e6 bp, supercoiling

small radius = faster growth rate because transport of waste and nutrients is faster.

Monomorphic- one shape through lifespan of bacteria

Pleomorphic- Shape changes throughout lifespan, cells become smaller as they age.

-Sporulation

plasma membrane folds into the cell giving a larger surface area for greater metabolic activity,

-occur in photosynthetic bacteria or high respiratory activity

Developed by Christian Gram

Gram Positve- blue

Gram Negative - pink

NAM:N-Acetylmuramic acid
NAG: N-Acetylglucosamine

Form peptidoglycan which forms the cellwall

-links four amino acids by peptide bonds

Peptidoglycan - Direct crosslinking and thinner membrane located in between outer membrane (LPS)and inner membrane

-LPS acts as a barrier against Host Defenses and Lipid A is an endotoxin

Peptidoglycan - Peptide interbridge of 5 Gly, Thick membrane

-Outermost layer, Periplastic space between wall and membrane

-Lipoteichoic acids- link wall to membrane

Capsule - Stringy ploysacharrides

S-Layer - Membrane of proteins

Thick Cell Wall - 9 aminoacid 5 gly + 4 normal

Thin Periplasm

Plasma Membrane

Capsule - Stringy polysacharrides

Outer Membrane- LPS/lipid bilayer & porin

Thin Cell Wall- 4 amino acids

Thick Periplasm

Plasma Membrane

G+ = Large G- = Small

G- contains enzymes that participate in nutrient
acquisition and metabolism

G+ has exoenzymes

Fimbriae and Pili on cell surface

-thin filaments of Pilin

Secretion systems to attach cells to prey

 -Receptors for virusa

- Conjugation

-essential for pathogenicity

Stalks attach to cells to surfaces

-extension of cytoplasm

Long, helical protein filaments

Proton Motive Force drive the rotation clockwise or anticlockwise

Flagella can bundle together to push cell forward in a RUN

They can spread apart and cause a TUMBLE

The ability of organisms to move towards or away from specific chemicals

Lipid monolayers

Storage of metabolites

Carboxysomes - lipid energy-storage granules

Actual lipid bilayer membrane -bound organelles with chains of Fe3O4 (Magnetite) crystal particles

Allows bacteria to orient and migrate along geomagnetic fields - magnetotaxis

Aquatic bacteria that grow best in low O2: Guide cells to sediments with low O2 levels

Composed of Protein GvpA and GvpC

• Spindle-shaped, hollow structures

• Permeable to gases, but not other substances

• Cause bacteria to float in aquatic

environments Bacterium can adjust to position in water that is optimal for photosynthesis

follows gradient

O2 and CO2 pass freely through membranes

Selective

Allows pass due to conformation change

faster than passive

Against Gradient

Highly Selective

Uses ATP to push protons out of cell, When they come back in they generate the Proton-Motive Force which is used to create ATP

Symport and Antiport

Sym - Pump 2 proteins in same direction

Anti- pumps 2 proteins in opposite direction

ATP-Binding Cassette

1) Periplasmic Solute Binding protein takes up a solute and then brings it to a membrane spanning transporter.

2) The SBP binds with the MST

3) The MST Converts ATP to ADP + P and which changes conformation and brings the solute in.

Solid medium favors formation of isolated colonies

-liquid just allows you to know bacteria has grew

Defined media: All constituents are known

Complex media: Unknown composition

Selective media: Favors the growth of particular
microorganisms while inhibiting the growth of others

Differential media: Can distinguish particular types of microbes based on certain biological characteristics

Cell division in prokaryotes

-Mother cell elongates and dupilcates DNA, Septum forms and cell splits into 2 cells

Lag Phase: Cells synthesizing materials, not dividing

• Exponential Phase: Fastest growth

• Stationary Phase: No change in cell number
– Depletion of nutrient(s) and/or accumulation of waste products

• Death: Decrease in cell number – cell lysis

Time for cell count to double = 1 generation

 N = No2^t-to/td

• Direct Methods
– Total Cell Counts (live + dead)
– Viable Cell Counts (live only)

• Indirect Methods
– Turbidity (live + dead)

Use a Petroff-Hauser Chamber to count cells directly

use stain to determine live from dead

Counts only those cells able to
reproduce

Make serial dilutions from liquid culture

MUST BE BETWEEN 30 and 300 colonies

Unkown Concentration -> 1ml into 9ml so dF=10 ->1ml into 9ml dF=100 -> 1ml into 9ml dF=1000

# of colonies * dF = Concentration

0.1ml                    

take AVG of concentrations to =total

Fast measurement

Measures turbidity

Solution must be at 10⁷–10¹⁰ cells/ml otherwise inacurate

• Most spore-forming bacteria are Gram-positive

vegetative cells - Occurs as bacteria age due to nutrient deprivation

spoulating cell -  A dormant structure developed within
Mature Spore is released after maturation and is Extremely resistant to harsh environments

Exosporium - outer wall and covers the spore coat

Spore coat - impermeable membrane

 Cortex- peptidoglycan layer

 Core Wall - surrounds the protoplast

DNA inside the core

1. Activation: Heating to sublethal temperature

2. Germination: Breaking of dormancy; very rapid; breaks and discards spore coat; loss of resistance

3. Outgrowth: Developing into active bacteria

in response to starvation

Substrate Mycelium -> BID genes expressed ->Whi genes expressed -> Aerial Mycelia -> endospore -> germination

can grow in the absence of O2

 Anaerobic organisms often found in
aquatic environments because O2 is
weakly soluble

– Chemicals applied to body surfaces

– Prevention of infection of living tissue by microorganisms

– Iodine, ethanol

– Use chemicals to internally kill or inhibit microbial growth within host tissues

– antibiotics

Selectively kills microbes
• Do not work on all species
– Has minimal effects on eukaryotic cells

• Can be used inside patients

• Pasteurization
– 63°C for 30 minutes

• Flash pasteurization
– 72°C for 15 seconds

UHT—Ultra-high temperature
– 150°C for 3 seconds
• Sterilizes—all bacteria killed

Sequential boiling

Boil to kill vegetative cells, incubate spores to get them to activate, boil again killing spores

Thymine dimer formation: major injury to DNA

– limited to surface sterilization; does not penetrate glass, water, and other substances

– Works best near 260 nm (short wavelength

Uses to remove bacteria in heat sensitive components

pores @ .22um

Breaking down molecules for energy

Chemoorganotroph - Organic Molecules

Chemolithotroph - inorganic molecules

Phototroph - light

Autotroph - CO2

Heterotroph - Organic Molecules

Organotrophs - Organic Molescules

Lithotroph - inorganic Molecules

Difference between w/ enzyme and w/o

G must be negative for reaction to occur

Enzymes are protein catalysts

 Increases the rate of a reaction by lowering the
activation energy, and is not transformed
during the reaction

 Enzymes have specific binding sites

ATP synthase motorized by
proton motive force (PMF) generated through
electron transfer.

Protons are pumped into
periplasmic space and pumped back in VIA ATP synthase -> oxidative phosphorylation makes ATP

H + NADH -(-2e)-> 2H + NADH

-2e into cytochrome -> H2O

Glucose 6C -(Glycolysis)-> 2 Pyruvate 3C

 -4 electrons to ETS via 2 NADH and 2H+

 -2ATP produced

-(+Lipids, amino acids and aromatic compounds

-2 CO2)->acetyl-CoA->

 -4 electrons to ETS via 2 NADH and 2H+

TCA Cycle-(electrons transfered to ETS by NADH)

 16 electrons to ETS via 6 NADH + 6H+ + 2FADH2

-produces 2 ATP + 4 CO2

-> 34 ATP

Convert pyruvate into other products

Rapid production of 2 ATP

substrate-level phosphorylation

no terminal electron acceptors

Pyruvate is completely oxidized to CO2

Only in the presence of inorganic terminal electron acceptors (most commonly O2)

 oxidative phosphorylation

Aerobic Respiration

ETS Pathway

TCA Electrons taken to NDH-1 by NADH.

NADH stripped of electrons by  Substrate
oxidoreductase to O2

then taken out of NDH-1 by Quinones to  Cytochromes

Electrons react with H2O2 to make H2O outside of cell

Anaerobic Respiration

&

Lithotrophy

Use of inorganic electron acceptors other than O2 in oxidative phosphorylation.

Less energy generation than aerobic respiration

Carried out only by prokaryotes

use Nitrogen, sulfur, maganese, iron to donate e-

CO2 accepts electrons and is reduced to methane

. High CO2 concentrations drive reaction
. CO2 + 4 H2 ->¨ CH4 + 2 H2O

Photolysis - A photoreceptor absorbs light and
excites electrons in the lumen

 The excited electrons enter ETS and pump protons outside cell generating proton gradient

 ATP and NADPH generated are used to fix CO2 and produce glucose

12 H2O + 6 CO2 ->C6H12O6 + 6 H2O + 6 O2