• prevent disease
• prevent spoilage
• prevent contamination

bacteriostatic

bacteriocide

sterilization

• keeps # of cells constant
• kills only bacteria (antibiotic)
• kills all microorganisms

target theory

d value

• more targets;more killing
• the amount of time it takes to kill 90% of targeted microorganism

• dose
• time 
• type of agent
• initial #

1. hot
2. cold
3. desiccation
4. uv radiation
5. filtration

• cooking
• pasteurization
• canning
• sterilizing

pasteurization

target org?

3 different types and their specifications?

Coxiella burnetti

• LTLT - 63C for 30 minutes
• HTST - 71C for 15 seconds
• UHT - 145C for 3 seconds

canning process specifications

sterilization specs?

• can - spores of Clostridium botulinism at 121C for 12 D-values
• sterile - spores of Bacillus stearothermophilus 121C for unknown time

water availability

osmophile

halophile

• love high sugar conc.
• love high salt conc.

drying

resistant orgs

sensitive orgs

• endospore formers, cysts, soil microbes
• any mucus membrane organism

sandwich sank to bottom with submarine

• a year later they rescued the sub and found the sandwich practically intact
• therefore pressure inhibits microbial growth

radiation 

most resistant microbe?

how?

dinococcus radiodurans

has multiple copies of the chromosomes, therefore can afford to have mutations in some and doesnt affect protein composition

1. oxygen
2. pH

acidophiles

alkalinophiles specs?

• Thiobacillus - low pH
• Notranobacterium - high pH

sterilants 

disinfectants

sanitizers

antiseptics

• disinfectant that kills all microorgs
• kills microbes;used on inanimate objects
• antiseptic used to kill pathogens
• kill microbes; used on animals

Generally regarded as Safe

• acids
• nitrites/nitrates
• benzoate/propionate

disease?

infection

intoxification

pathogen

parasite

d- any impairment in the fxn of the host

infection - parasite enters the host and causes disease

intox - host infected with toxic product of a bacteria that causes diesease

pathogen - any microorg that causes disease

parasite - any microorg that causes infection

• skin, hair follicles, flushing enzymes, mucus membranes
• increase pH, normal flora in mucus membrances, tears, saliva

• thymus -> t cells
• bone marrow -> B cells
• lymph nodes
• spleen
• mucosal associtated lymph tissue (MALT)

• occurs from tissue damage
• capillary dilation
• redness/swelling
• attracts phagocytes
• heat

1. chemotaxis
2. attachment
3. engulfment
4. fusion
5. digestion

• specific
• induced
• tolerance
• memory

B cells located in?

mature in?

differentiate into?

have what on surface?

located in spleen of lymph

mature in bone marrow

differentiate into plasma or memory cells

have MHC 2 on cell surface

located in spleen, blood, lymph

mature in thymus gland

have t cell receptors CD4 CD8

macrophages located in?

have what on surface?

present.....on surface after digesting foreign substance?

one of the 3....

• blood, tissues
• MHC 2
• antigens
• anitgen presenting cells

dendritic cells located in?

have what on surface?

what does MHC stand for? what cells ahve it?

• just below the surface of the skin
• MHC 2
• major histocompatibility complex
• dendritic, B cell, macrophage

IgG

IgM

IgA

IgE

• B cells differentiate into plasma cells which produce antibodies
• Cytokines (interleukins) released by leukocytes 

1. present on all cells except non-nucleated cells
2. only present on Antigen presenting cells

inactivate toxin - block fxn

viral inactivation - bind antigens to block fxn

complement fixation - signal pathway to kill

opsonization- digesting

Active immunity

• natural 
• artificial

• naturally exposed to antigen and produce Abs
• injected antigen that mounts an immune response

passive immunity

• natural 
• artificial

• anitbody-mediated immunity conveyed to the fetus from the mother
• short term - transfer of abs

cell mediated immunity 

protective responses?

• cytotoxic T cell causes cell death
• inflammatory T Cell signals macrophages to release cytokines to increase phagocytosis and inflammation

poison ivy

transplant rejection

Modern Germ theory

who how disease

pathogen

Robert Koch

isolated disease

anthrax

bacillus anthracis

1. microorg must be found in abundance all orgs suffering from disease
2. isolated and grown in pure culture
3. cause disease when injected in healthy organism
4. reisolated from the innoculated, and found identical to original

virulence

virulence factors

• disease severity or pathogens infectivity
• molecules expressed or secreted by pathogens that enable them to prosper in host

• pili (Neisseria gonorrhoeae)
• glycocalyx (sticky) streptococcus mutans
• S-Layer (Streptococcus pyogenes)

• glycocalyx capsule
• inhibit chemotaxis of PMNs
• Wax
• coagulase
• kill phagocyte

• non professional phagocytosis
• enzymatic penetration
• survival in phagocytes
• antigenic and phase variation

• exotoxins 
• streptokinase
• coallagenase
• endotoxins
• hemolysin

• siderophores - capture iron even in low concentrations

toxic virulence factors

endotoxin

exotoxin (enzymes also)

• endotoxin
• lipopolysaccharide
• in all gram -
• less potent than exotoxins; heat stable
• diverse effects
• exotoxin (enzymes also (hemolysin))
• proteins
• both gram - and +
• potent; heat liable
• specific effects
• neurotoxin

Cholera 

pathogen

source

virulence factors

treatment and prevention

• vibrio cholerae
• untreated water; asymptomatic carriers
• adhesion to intestinal walls
• invasive enzymes that cause diarrhea
• replace fluids and water treatment

• ammonification
• nitrification
• produces NO3 which is the only usable form of nitrogen for plants
• denitrification
• nitrogen fixation

• Penicillium crysogenum
• blocks peptidoglycan synthesis

Streptomyces griseus

blocks protein synthesis in 70s ribosomes