Bacterial growth Flashcards
BACTERIAL GROWTH REQUIREMENTS: Atmospheric
- oxygen acts as _____
- catalyzed by ____ & _____
- generates 2 toxic molecules
- 2 enzymes
- hydrogen acceptor
- flavoproteins & cytochromes
- hydrogen peroxide
& radical superoxide - superoxide dismutase, catalase
Aerobe:
1. require oxygen and grow well at room air
- requirement
Anaerobe
1. strictly does not require the presence of oxygen
- requirement
2. fundamentally aerobes; do not require oxygen but grows better in the presence of oxygen
- requirement
Aerobe:
1. OBLIGATE AEROBE
- 21% oxygen & 0.03% carbon dioxide
Anaerobe
1. OBLIGATE ANAEROBES
- 85% Nitrogen, 10% hydrogen, 5% carbon dioxide
2. FACULTATIVE ANAEROBES
- 85% Nitrogen, 10% hydrogen, 5% carbon dioxide
- can grow with or without oxygen, but only use anaerobic metabolism
- enzyme - low oxygen tension
- requirement - microaerophiles that are dependent on carbon
dioxide (increased)
- requirement
- AEROTOLERANT
- superoxide dismutase - MICROAEROPHILES
- 5-10% oxygen, 8-10% carbon dioxide - CAPNOPHILE
- 5-10% carbon dioxide
- lowest temperature required to kill
organisms in a constant temperature - lowest temperature required to kill
an organism in a constant time - incubation temp. of bacteria & viruses
- 2 bacteria that can grow both at 35C & 42C
- Thermal Death Time
- Thermal Death Point
- 35-37C
- Pseudomonas & Camplyobacter
Thermal Reqs
- extreme cold temp.
- optimum temp - cold temp.
- optimum temp
- range temp
- 2 bacteria - moderate temp.
- optimum temp
- range temp
- Psychodurics
- <0C - Psychrophiles
- 4-8C
- 0-20C
-Listeria monocytogenes; Yersenia enterocolitica - Mesophiles
- 30-37C
- 20-40C
Thermal Reqs
- heat temp.
- optimum temp
- range temp
- basis of effectivity of sterilization - extreme heat temp.
- temp - able to live at unusual
carbon dioxide conditions
- survive up to
- example
- Thermophiles
- 60C
- 45-90C
- Bacillus stearothermophilus - Thermodurics
- >90C - Extremophiles
- 180C
- Bacillus infernus
pH Requirements
- decreased pH range
- this bacteria is cultivated with tomato juice agar - neutral pH range
- diagnostic lab culture medium - increased pH range
- 0-5.5
- Lactobacillus acidophilus - 5.5-8.9
- 7.0-7.5 - 8.5-11.5
Salt Concentration Requirements
- grows in high salt concentration
- Enterococci
- Staphylococcus aureus
- Vibrio
- V mimicus & V cholerae - may survive at 2% salt concentration
- grows in less salt concentration
- Halophiles
- 6.5% NaCl conc.
- 7.5% NaCl conc.
- 8-10% NaCl conc.
- 1-3% NaCl conc - Facultative Halophiles
- Non-halophiles
Nutritional Requirements
energy source
1. Phototrophic
2. Chemotrophic
carbon source
1. autotrophic
2. heterotrophic
energy source
1. Light
2. Chemical compound
carbon source
1. Inorganic
2. Organic
Nutritional Requirements
Photoautotrophs:
1. Energy source
2. Carbon source
3. Bacteria
Photoheterotrophs
1. Energy source
2. Carbon source
3. Bacteria
Photoautotrophs:
1. light energy
2. carbon dioxide
3. Cyanobacteria
Photoheterotrophs
1. light energy
2. organic compounds
3. green sulfur & purple sulfur bacteria
Nutritional Requirements
Chemoautotrophs:
1. Energy source
2. Carbon source
3. Bacteria
Chemoheterotrophs
1. Energy source
2. Carbon source
3. usual source which helps in fermentative & respiratory growth
- require dead organic substances
- require organic substances from living tissues
Chemoautotrophs:
1. inorganic
2. carbon dioxide
3. Archaea
Chemoheterotrophs
1. organic
2. organic
3. glucose
- saprophytes
- parasites
Other Requirements
1. major constituent of culture medium
2. Pressure; organisms that grow in the presence of high pressure
- atmospheric pressure
- 3 bacteria
3. amino acids, nitrogenous bases, vitamins that are needed by fastidious bacteria as they have certain requirements to proliferate
- Moisture
- Barophiles
- 600 to 1100 atm pressure
- Photobacterium, Shewanella, Colwell - Growth Factors
