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Bacterial Requirements

Growth and Nutrition

Bacterial Reproduction

ReproductionBinary FissionBuddingFragmenting

FunctionIncrease number of cellsGenetic recombination possible

End result : Growth

Generation Time

DefineTimeReasonRequirements

PhysicalChemical

ResultGenetic recombinationMutations

Growth Curve Graph

Growth Curve Labeled Phases

Lag phaseAdaptiveStart metabolism1-3 days

Log phaseGeneration time doublesMost metabolically active

Stationary phaseGrowth = death

Death phaseRequirements decreasePossible spore formation

Growth Curve Changes due to AB

Measurement of Microbial Growth

CFUSerial DilutionsPour PlateSpread PlateDirect

Number counted / fovIndirect

TurbidityMetabolic activity

Nutritional Requirements

Macro and Trace Elements

Nutritional Element Use

CarbonOxygenNitrogenHydrogenPhosporusSulfur

Main componentCell water, aerobic respirationAA, NA, coenzymesH20Nucleotides, PL, LPSSeveral AA; coenzyme

Cycles

Metal Ions and Trace Minerals

PotassiumMagnesiumCalciumIronCoboltZincCopperManganese

Cofactors in enzymatic reactions in the cell

Growth Factors: Vitaminsinvolved in many

Metabolic Reactionsredoxdeaminationdecarboxylationtransaminationsynthesis

Folic AcidBiotinNiacinPantothenic acidRiboflavin [B2]Thiamine [B1]Pyridoxine [B6]B12K

Oxygen Requirements

Obligate AerobesMicroaerophilesAerotolerant aerobesObligate AnaerobesFacultative AnaerobesCapnophiles

Oxygen Requirement Classification

Aerobic / Anaerobic Lab Tests

aerobe FA aerotolerant anaerobe

Oxygen Forms

NormalToxic

Singlet: 1O2 with electrons in higher energy stateSuperoxide radical: O2-Peroxide Anion: O2=Hydroxide radical: OH-from incomplete reduction of hydrogen peroxide [H2O2]

Enzyme Presence to Detoxify O2 -Superoxide Catalase Peroxidase

Abligate Aerobes and FA + + -Aerotolerant Anaerobes + - +Obligate anaerobes - - -

Catalase Test

Bacterial Examples of O2 Groups

Obligate AerobesPseudomonas

MicroaerophilesH. pylori

Aerotolerant aerobesStreptococcusLactobacillus

Obligate AnaerobesClostridium

Facultative AnaerobesE. coliStapylococcus

CapnophilicCampylobacter

E coli

Staph

Physical Requirements: pH

pH Groups

AcidophileBacillus acidocaldariusLactobacillus acidophilus

NeutrophileE. coliStaphylococcus aureus

AkaliphileStreptococcus pneumoniaeNitrobacter sp.

Physical Requirements: Temperature

PsychrophileUnsaturated FA in cell membrane

PsychrotrophRefrigerationRoom temperature

MesophileWarm Blooded Animals

ThermophileSaturated FA in cell membrane

Psychrotrophs and Mesophiles

Bacterial Examples: Temperaturepsychrophile psychrotroph

mesophile thermophile

mold

Archaea

Vibrio

E coli

Physical Requirements: Salt

Extreme Halophile : 30 % NaClObligate Halophile : 15% NaClFacultative Halophile : 2% NaClHalotolerant : NaCl not needed, can grow in low salt

Extreme Halophiles

Great Salt Lake

Osmosis and Water Activity

Activity of water [Aw] = 1.0 for pure water

Aw for human blood = 0.99

Range required 0.7-1.0 AwE.coli requires Aw of 0.91Stapylococcus requires Aw of 0.85

Nutritional Groups

PhotoautotrophsChemoautotrophsPhotoheterotrophsChemoheterotrophs

Many bacteriaMost all Eukarya

How Acquire ElectronsOrganotrophsLithotrophs

Symbiotic Relationships

Close ecological relationship between individuals of two or more different species

MutualismCommensalismSynergismParasitismCompetitionNeutralismBiofilms

Mutualism: Both Benefit

Human Eye-lash mite

Bacterial Symbiosis

Biofilms

Parasitism

Agar

Culturing Organisms

InoculumMediumPure CultureSterile

Cultivation Media

Chemically DefinedComplex Undefined

General UseEnrichedSelectiveDifferentialAnaerobic

Cultural Characteristics

Solid Media [Petri]ColorSizeShape ElevationMargin

Broth MediaSlantGelatin Liquefaction

Colony Characteristics on Agar Plate

Complex General Media:Nutrient (TSA) Agar

Enriched Media

Selective and Differential Media

C-CNA MAC

MSA EMB

Special Media

SABMH-T

SS Snyder Deep

Anaerobic Culture Methods

Isolation Techniques

Biochemical Reactions

Questions?