Bacterial Requirements Growth and Nutrition Bacterial Reproduction n
Bacterial Requirements Growth and Nutrition
Bacterial Reproduction n Reproduction q q q n Function q q n Binary Fission Budding Fragmenting Increase number of cells Genetic recombination possible End result : Growth
Binary Fission
Budding versus Fission
Fragmenting
Generation Time n n Define Time Reason Requirements q q n Physical Chemical Result q q Genetic recombination Mutations
Growth Curve Graph
Growth Curve Labeled Phases n Lag phase q q q n Log phase q q n Generation time doubles Most metabolically active Stationary phase q n Adaptive Start metabolism 1 -3 days Growth = death Death phase q q Requirements decrease Possible spore formation
Growth Curve Changes due to Ab
Measurement of Microbial Growth n n CFU Direct q Viable Plate Counts n n n q q q n Serial Dilutions Pour Plate Spread Plate Membrane Filtration Counting Chamber MPN (fecal, H 20, food) Indirect q q Turbidity Metabolic activity
Nutritional Requirements
Macro and Trace Elements
Nutritional Element Use n n n Carbon Oxygen Nitrogen Hydrogen Phosphorus Sulfur n n n Main component Cell water, aerobic respiration AA, NA, coenzymes H 20 Nucleotides, PL, LPS Several AA; coenzyme
Cycles
Metal Ions and Trace Minerals n n n n Potassium Magnesium Calcium Iron Cobolt Zinc Copper Manganese Cofactors in enzymatic reactions in the cell
Growth Factors: Vitamins n n n n n Folic Acid Biotin Niacin Pantothenic acid Riboflavin [B 2] Thiamine [B 1] Pyridoxine [B 6] B 12 K involved in many Metabolic Reactions redox deamination decarboxylation transamination synthesis
Nutrient Uptake n Diffusion q q q n Active Transport q q n Simple (passive) Facilitated Osmosis ATP H+ (protomotive) Group Translocation q q Alter molecule PTS (phosphorylate)
Group Translocation
Membrane Transport Summary
Oxygen Requirements n n n Obligate Aerobes Microaerophiles Aerotolerant aerobes Obligate Anaerobes Facultative Anaerobes Capnophiles
Bacterial Examples of O 2 Groups n Obligate Aerobes q n Microaerophiles q n q E coli Clostridium Facultative Anaerobes q q n Streptococcus Lactobacillus Obligate Anaerobes q n H. pylori Aerotolerant aerobes q n Pseudomonas E. coli Stapylococcus Capnophilic q Campylobacter Staph
Oxygen Requirement Classification
Aerobic / Anaerobic Lab Tests aerobe FA aerotolerant anaerobe
Oxygen Forms n n Normal Toxic q q Singlet: 1 -O 2 with electrons in higher energy state Superoxide radical: O 2 Peroxide Anion: O 2= Hydroxide radical: OHfrom incomplete reduction of hydrogen peroxide [H 2 O 2]
Radiation n n EM radiation spectrum Source q Sun n n q Ionizing Radiation n Visible light UV Infrared Radio waves X rays Gamma rays Create ROS
Enzyme Presence to Detoxify O 2 Superoxide n n n Abligate Aerobes and FA Aerotolerant Anaerobes Obligate anaerobes SOD + + - Catalase Peroxidase + -
Catalase Test
Physical Requirements: p. H Define p. H mathematically Know number range
p. H Groups n Acidophile q q n Neutrophile q q n Bacillus acidocaldarius Lactobacillus acidophilus E. coli Staphylococcus aureus Akaliphile q q Streptococcus pneumoniae Nitrobacter sp.
Physical Requirements: Temperature n Psychrophile q q n Psychrotroph (facultative psychrophiles) q q n Refrigeration Room temperature Mesophile q n Unsaturated FA in cell membrane Cold temperatures Warm Blooded Animals Thermophile/Hyperq Saturated FA in cell membrane
Psychrotrophs and Mesophiles
Bacterial Examples: Temperature psychrophile psychrotroph mold Vibrio mesophile E coli thermophile Archaea
Physical Requirements: Salt n n Extreme Halophile : 30 % Na. Cl Obligate Halophile : 15% Na. Cl Facultative Halophile : 2% Na. Cl Halotolerant : Na. Cl not needed, can grow in low salt
Extreme Halophiles Great Salt Lake
Osmosis and Water Activity n n n Activity of water [Aw] = 1. 0 for pure water Aw for human blood = 0. 99 Range required 0. 7 -1. 0 Aw q q E. coli requires Aw of 0. 91 Stapylococcus requires Aw of 0. 85
Physical Effect of Water n n Define osmosis Osmotic Pressure q Tonicity n n n q q n Isotonic Hypertonic Hypotonic Effects Osmotolerant Hydrostatic Pressure q q Barotolerant Barophiles (deep ocean)
Nutritional Groups n n Photoautotrophs Chemoautotrophs Photoheterotrophs Chemoheterotrophs q q n Many bacteria Most all Eukarya How Acquire Electrons q q Organotrophs Lithotrophs
Symbiotic Relationships n Close ecological relationship between individuals of two or more different species n n n n Mutualism Commensalism Synergism Parasitism Competition Neutralism Biofilms
Mutualism: Both Benefit Human Eye-lash mite
Bacterial Symbiosis
Biofilms Slime layer Fimbria
Parasitism
Agar
Culturing Organisms n n Inoculum Medium Pure Culture Sterile
Cultivation Media n n Chemically Defined Complex Undefined q q q General Purpose Enriched Selective Differential Anaerobic
Cultural Characteristics n Solid Media [Petri] q q q n n n Color Size Shape Elevation Margin Broth Media Slant Gelatin Liquefaction
Colony Characteristics on Agar Plate
Complex General Media: Nutrient (TSA) Agar agar broth slant
Enriched Media BAP Chocolate agar
Selective and Differential Media C-CNA MSA MAC EMB
Special Media MH-T SS SAB Snyder Deep
Anaerobic Culture Methods
Isolation Techniques
Biochemical Reactions
Questions?
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