II Control of microbial
growth
A.
Terms
1.
Sterilization
2.
Disinfection
3.
Antiseptic
4.
Sanitize
B. How
to kill microbes?
1.
Nonspecific methods
a.
Physical (heat)
b.
Chemical (phenols, alcohol, halogens)
2.
Specific - antibiotics
a.
Discovery
b. How
do they work?
c.
Cellular Target Sites (cell wall, plasma membrane,
nucleic acids, proteins)
a. Timeline
b. Increase
a. Timeline
1928 - Penicillin discovered
1930s & on - Rapid discovery of many new
antibiotics
1940s - Penicillin use begins
1960s - Many infectious diseases
declining, govt cuts
research
funding
1980s - Less research to discover new
antibiotics
(penicillin
= magic bullet)
1990s - rapid increase in resistance
Emerging
antibiotic resistance
Enterococci
Staphylococcus aureus
Streptococcus pneumoniae
Mycobacterium tuberculosis
Penicillin resistant Staphylococcus
aureus
Post-surgical prophylaxis
Antibiotics not regulated in foreign countries
Low doses used for growth promotion
Patients expect antibiotics even for viral infections
Parents demand antibiotics of pediatricians
1 out of 3 doctors sometimes or usually give in
Chapter 5 Metabolism
III. Metabolism
A. Catabolism
B. Anabolism
C. ATP
D. Enzymes
Properties
Factors that influence activity
Temperature
pH
Substrate concentration
Inhibitors
E. Energy production
Redox
Catabolism
Fermentation
Aerobic respiration
Anaerobic respiration
Metabolism is the sum of the chemical reactions in an organism.
Catabolism is the energy-releasing processes. Breaking chemical bonds
Anabolism is the energy-using processes. Building chemical bonds.
Microbes in disease
Biodeterioration
Snot-tites
Energy from
inorganic chemicals (H2S)
H2SΰH2S04
Oxidation = energy release
ATP - link between catabolism and anabolism
Fig. 5.1
Fig. 2.18
Substrate cleavage
Fig. 5.4
Enzymestructure
Apoenzyme
Apoenzyme - Holoenzyme
Nicotinamide Adenine
Dinucleotide
Important
coenzyme
What influences enzyme activity?
Mode of Action of high temps.
Bacteriocidal
pH
Substrate
concentration
Saturation of active sites
Enzyme inhibitors - competitive
Sulfa Drugs compete for PABA binding site.
Bacteriostatic
Resistant stains have rendered most ineffective
Non-competitive or
allosteric
Dont bind to active site, but change shape
Can bind irreversibly
Redox reaction
Energy Transferred
electron lost (hydrogen)
energy released
Reduction
electron gained (hydrogen)
energy bound
Nicotinamide
Adenine Dinucleotide
Oxidized form
Reduced form
Redox reaction with e- carrier (NAD)
III. Metabolism
A. Catabolism
B. Anabolism
C. ATP
D. Enzymes
Properties
Factors that influence activity
Temperature
pH
Substrate concentration
Inhibitors
E.
Energy production
Redox
Catabolism
Fermentation
Aerobic respiration
Anaerobic respiration