03 bacterial growth
TRANSCRIPT
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BacteriaBacteria
Metabolism, growth and epidemiologyMetabolism, growth and epidemiology
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Metabolism
Metaballein = changeMetaballein = change
All the chemical processes takingAll the chemical processes taking
place within a cell.place within a cell.
Nutrient = sources of basic elementsNutrient = sources of basic elements
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Metabolism
Two phasesTwo phases
Breakdown of macromolecules andBreakdown of macromolecules and
release of energy and waste productrelease of energy and waste product
catabolismcatabolism
Assemble of basic elements toAssemble of basic elements to
macromolecules and utilization ofmacromolecules and utilization of
energyenergy biosynthesis/anabolismbiosynthesis/anabolism
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Energy producing processes
ProkaryotesProkaryotes
Aerobic respirationAerobic respiration
Fermentation: EmbdenFermentation: Embden--Meyerhof pathway,Meyerhof pathway,
and Entnerand Entner--Doudoroff pathway.Doudoroff pathway.
Anaerobic respirationAnaerobic respiration
Anoxygenic photosynthesisAnoxygenic photosynthesis
LightLight--driven nonphotosyntheticdriven nonphotosynthetic
photophosphorylationphotophosphorylation
MethanogenesisMethanogenesis
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Metabolic strategies in heterotrophs
Aerobic respirationAerobic respiration
Glycolysis, TCA cycle, electronGlycolysis, TCA cycle, electron
transporttransport
OO22 final efinal e-- acceptoracceptor
Products: ATP, COProducts: ATP, CO22, H, H22OO
Aerobes, facultative anaerobesAerobes, facultative anaerobes
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Glycolysis breakdown of glucose
Also called EmbdenAlso called Embden--MeyerhofMeyerhof
pathway. (EMP)pathway. (EMP)
Anaerobic processAnaerobic process
The pathway is most operated byThe pathway is most operated by
most microbes.most microbes.
Nine linear stepsNine linear steps
First pathFirst path addition ofaddition of
phosphatephosphate
The restThe rest electron transport andelectron transport and
removalremoval of phosphateof phosphate
Energy use: 2 ATPEnergy use: 2 ATP
Energy gain: 4 ATP + 2 NADHEnergy gain: 4 ATP + 2 NADH
Product: 2 pyruvatesProduct: 2 pyruvates
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Aerobic respiration
Pyruvate acetylPyruvate acetyl--CoA + 2COCoA + 2CO22 + 2+ 2
NADHNADH22
Tricarboxylic acid cycle (TCA aka Krebs)Tricarboxylic acid cycle (TCA aka Krebs)
Complete oxidation of substrateComplete oxidation of substrate
Total energy yield:Total energy yield:
-- 2 FADH2 FADH22
-- 6 NADH6 NADH22
-- 2 ATP2 ATP
a
b
c
a = 6C, b = 5C, c = 4C
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TCA cycle
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Metabolic strategies in heterotrophs
FermentationFermentation
GlycolysisGlycolysis
Final eFinal e-- acceptoracceptor organicorganic
moleculesmolecules
Products: ATP, COProducts: ATP, CO22,,ethanol, lactic acid,ethanol, lactic acid,
othersothers
Facultative, aerotolerant,Facultative, aerotolerant,
strict anaerobesstrict anaerobes
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LAB Yeast
Propionicbacteria
EnterobactorEntericbacteria
Clostridium
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Other pathways (to pyruvate)
Pentose phosphatePentose phosphate
shuntshunt
Important in theImportant in the
biosynthesisbiosynthesis
of 4 and 5 carbon sugarsof 4 and 5 carbon sugars
(ribose)(ribose)
Aerobically orAerobically oranaerobicallyanaerobically
Produces NADPHProduces NADPH
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Other pathways (to pyruvate)
EntnerEntner--Douderoff PathwayDouderoff Pathway
A substitute for glycolysisA substitute for glycolysis
Produces 1 pyruvate andProduces 1 pyruvate and
1 glyceraldehyde1 glyceraldehyde--3 phosphate3 phosphate
per glucoseper glucose
GlyceraldehydeGlyceraldehyde--33--phosphatephosphate
pyruvatepyruvate
Net 2 ethanol, 2 CONet 2 ethanol, 2 CO22, 1 ATP per, 1 ATP per
glucoseglucose
ZymomonasZymomonas Maguey cactusMaguey cactus
cactus beer (tequila production)cactus beer (tequila production)
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Bacterial Growth
Increase size, number
Cellular level binary fission http://trc.ucdavis.edu/biosci10v/bis10v/media/ch14/prokaryotic_fission.html
IncreaseIncrease size, numbersize, number
Cellular levelCellular level binary fissionbinary fission http://trc.ucdavis.edu/biosci10v/bis10v/media/ch14/prokaryotic_fission.html
http://trc.ucdavis.edu/biosci10v/bis10v/week7/20f/Slide4.gif
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Bacterial population growth
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Nutrient
Essential nutrientEssential nutrient
Nutrient needed by cells to surviveNutrient needed by cells to survive
Cell component:Cell component:
WaterWater 70%70%
Organic compounds 97% of Dry WeightOrganic compounds 97% of Dry Weight(DW)(DW)
Major elements (CHNOPS)Major elements (CHNOPS) 96% DW96% DW
Other elements (K, Na, Ca, Mg, Cl, Fe, Mn,Other elements (K, Na, Ca, Mg, Cl, Fe, Mn,Zn, Mo, Cu, Co, vitamin)Zn, Mo, Cu, Co, vitamin)
Example: cell component ofExample: cell component of E. coliE. coli
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Escherichia coli (E. coli)
70
15
7
33
1
0.2
Water
Protein
Nucleic acids
PolysaccharidesLipids
Inorganic ions
Metabolites
Percentage (% wet weight)Components
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Nutrients
MacronutrientsMacronutrients CHNOPSCHNOPS
Require in relatively large amountRequire in relatively large amount
UsageUsage cell structure, energycell structure, energy
(macromolecules)(macromolecules)
Common in all organismsCommon in all organisms
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Nutritional types
Carbon sourcesCarbon sources
Main molecule for structuralMain molecule for structural
backbone of organic compoundsbackbone of organic compounds
Heterotrophs/autotrophsHeterotrophs/autotrophs
Energy sourcesEnergy sources PhototrophsPhototrophs: use light (radiant: use light (radiant
energy)energy)
ChemotrophsChemotrophs: depend on: depend onoxidationoxidation--reductionreduction of chemicalof chemicalcompoundscompounds
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Nutritional typesNutritional types
Protozoa, fungi, many
bacteria and some Archea
Other organismsOrganicChemoheterotrophs
Some purple and greenbacteria
SunlightOrganicPhotoheterotrophs
Other organismsor sunlight
OrganicHeterotroph
A few Bacteria and manyArcheaSimple inorganicchemical (H2,NH
3, NO
2, H
2S)
CO2Chemolithoautotrophs
Cyanobacteria, somePurple and Green bacteria
SunlightCO2
Photoautotrophs
NonlivingEnvironment
CO2Autotroph
ExampleEnergy sourceCarbonsource
Category
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Environmental factors affecting growth
TemperatureTemperature
Optimum temperatureOptimum temperature
Body temperature = 37Body temperature = 37CC human pathogenhuman pathogen
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Environmental factors affecting growth
Oxygen (OOxygen (O22) requirement) requirement
Air ~20% oxygenAir ~20% oxygen
OO22 toxic to some cellstoxic to some cells
Reaction in cellsReaction in cells produceproduce
HH22OO22 (peroxide) or O(peroxide) or O22--
((superoxidesuperoxide) and some may) and some may
produce singlet oxygen.produce singlet oxygen.
Catalase and/orCatalase and/or superoxidesuperoxide
dismutasedismutaseOxygen level in the
ocean at different depth
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Environmental factors affecting growth
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Microbes and human: Normal flora
Animal bodies - favorable
environments for the growth of
many microorganisms;
rich in organic nutrients and growth
factors,
relatively constant conditions of pH
and osmotic pressure,
highly constant temperature (warm-
blood animals).
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Microbes and human: Normal flora
An adult human body consists of ~ 1013
(10 million million) eukaryotic cells.
Before birth a fetus exists in a sterile
environment.
At birth certain microorganisms becomepermanently or temporarily associated
with it.
These organisms are referred to
collectively as normal flora.
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Microbes and human: Normal flora
3 categories :
Species always present on or in the
human body - the resident flora(indigenous flora).
Some microbes present only in a short
time = transients Some of these flora can cause disease
in compromised host = opportunists
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The skin
Staphylococcus epidermidisCorynebacterium diphtheriae
(acne )
Propionibacterium acnes
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Pathogens
Microbes that cause diseasesMicrobes that cause diseases True pathogens (primary pathogens):True pathogens (primary pathogens):
capable of causing disease in healthycapable of causing disease in healthy
person.person.
Opportunistic pathogens =?Opportunistic pathogens =?
Can be divided intoCan be divided into Class 1:Class 1: Micrococcus luteusMicrococcus luteus
Class 2: Moderate risk e.g.Class 2: Moderate risk e.g. S. aureusS. aureus
Class 3: Viral and transmitted e.g.Class 3: Viral and transmitted e.g.Mycobacterium tuberculosisMycobacterium tuberculosis
Class 4: Deathly e.g. Ebola virusClass 4: Deathly e.g. Ebola virus
P h i i
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Pathogenicity
The ability to cause infection orThe ability to cause infection or
disease.disease.
Virulence: precise factors used toVirulence: precise factors used toinvade and damage host tissue;invade and damage host tissue;
degree of pathogenicitydegree of pathogenicity
Can be single or multiple factors.Can be single or multiple factors.
Cell surface architecture: adhere,Cell surface architecture: adhere,
phagocytosisphagocytosis Production of toxic proteins or enzymesProduction of toxic proteins or enzymes
May not be clearly established.May not be clearly established.
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I t t th
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Important pathogens
StaphylococcusStaphylococcus aureusaureus
Gram +, cocci, produceGram +, cocci, produce coagulasecoagulase enzymeenzyme
Normal floraNormal flora
Infect the skin, produce toxins (Infect the skin, produce toxins (exotoxinsexotoxins))
Contaminated in food, secondary infection ofContaminated in food, secondary infection of
woundswounds
SymptomsSymptomsIngestionIngestion diarrhea, nausea,diarrhea, nausea, vomittingvomitting
Skin/wound infectionSkin/wound infection -- superficialsuperficial bullaebullae, impetigo, impetigo
Important pathogens
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Important pathogens
Streptococci:Streptococci: StreptococcusStreptococcus pyogenespyogenes
Gram +, cocciGram +, cocci
Infect pharynx or skinInfect pharynx or skin
Only in weaken individualOnly in weaken individual
Spread through respiratory dropletsSpread through respiratory droplets DiseasesDiseases
PharyngitisPharyngitis sour throat (strep throat)sour throat (strep throat)
Scarlet feverScarlet fever body rashbody rash
Necrotizing fascisticNecrotizing fascistic fresh eating strepfresh eating strep
Important pathogens
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Important pathogens
Streptococci:Streptococci: StreptococcusStreptococcus pyogenespyogenes
DiseasesDiseases
Rheumatic feverRheumatic fever develop from untreateddevelop from untreatedstrep throatstrep throat damage of heart valves anddamage of heart valves and
musclesmuscles
GlomerulonephritisGlomerulonephritis kidneykidney inflamationinflamation
Scarlet feverScarlet fever
Strep throat
Important pathogens
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Important pathogens
BacillusBacillus:: BacillusBacillus anthracisanthracis
Gram +, rod shaped, produceGram +, rod shaped, produce
endospores but not in specimenendospores but not in specimen
Anthrax toxinAnthrax toxin lethallethal
TransmittedTransmitted sporesspores
SymptomsSymptoms
CutaneousCutaneous anthraxanthrax painless, solid, raisedpainless, solid, raisednodulenodule
No antitoxin availableNo antitoxin available have vaccinehave vaccine
Important pathogens
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Important pathogens
ClostridiumClostridium:: ClostridiumClostridium perfringensperfringens
Gram +, rod shaped, produce endosporesGram +, rod shaped, produce endospores
Strictly anaerobesStrictly anaerobes
Food contamination and wound infectionFood contamination and wound infection
SymptomsSymptoms Diarrhea, watery stoolDiarrhea, watery stool not severenot severe
Necrosis in gas gangreneNecrosis in gas gangrene woundwound
Removing dead tissue and antibioticsRemoving dead tissue and antibioticsadministrationadministration
Important pathogens
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Important pathogens
ClostridiumClostridium:: ClostridiumClostridium botulinumbotulinum
Botulism toxinsBotulism toxins deadliest toxindeadliest toxin
Neurological toxinNeurological toxin effect nerve cellseffect nerve cells
Food (canned food), woundsFood (canned food), wounds SymptomsSymptoms
Cause by toxinCause by toxin crying, constipation,crying, constipation,failure to thrivefailure to thrive
BotulinumBotulinum antitoxin availableantitoxin available
Important pathogens
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Important pathogens
CorynebacteriumCorynebacterium:: CorynebacteriumCorynebacterium
diphtheriadiphtheria
Gram +, bacilli, aerobicGram +, bacilli, aerobic
Respiratory droplet or skin contactRespiratory droplet or skin contact
Diphtheria toxinDiphtheria toxin
SymptomsSymptoms
Sore throat, localized pain, fever,Sore throat, localized pain, fever,
pharyngitispharyngitis and oozing of fluidand oozing of fluid
Important pathogens
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Important pathogens
ListeriaListeria -- ListeriaListeria monocytogenesmonocytogenes
Gram +, rod shapedGram +, rod shaped
Food and drinkFood and drink
ListeriosisListeriosis -- severe insevere in
immunocompromisedimmunocompromised patientpatient
SymptomsSymptoms
Sepsis (blood infection) andSepsis (blood infection) and Meningitis (brain inflammation)Meningitis (brain inflammation)
Important pathogens
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Important pathogens
MycobacteriumMycobacterium Gram +, rod shapedGram +, rod shaped
Mycobacterium tuberculosisMycobacterium tuberculosis TuberculosisTuberculosis SymptomsSymptoms
TuberculosisTuberculosis lung infectionlung infection
Formation of tubercles (small, hard nodule)Formation of tubercles (small, hard nodule)
Stay dormant >10 yearsStay dormant >10 years Reactivation of tuberculosisReactivation of tuberculosis
Skin testSkin test
Important pathogens
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Important pathogens
MycobacteriumMycobacterium M.M. lepraeleprae -- leprosyleprosy
SymptomsSymptoms
leprosyleprosy showed in cooler part of bodyshowed in cooler part of body TuberculoidTuberculoid leprosyleprosy nerve cell damagenerve cell damage
LepromatousLepromatous leprosyleprosy weak immune responseweak immune response
Direct contactDirect contact
Important pathogens
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Important pathogens
VibrioVibrio
GramGram --, curved bacilli, curved bacilli
VibrioVibrio choleracholera -- choleracholera
Food and drinkFood and drink marine environmentmarine environment
Cholera toxinCholera toxin
SymptomsSymptoms
Asymptomatic to diarrheaAsymptomatic to diarrhea Rapid, severe, and fatal fluid andRapid, severe, and fatal fluid and
electrolyte losselectrolyte loss
Important pathogens
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Important pathogens
NeisseriaNeisseria
GramGram --, cocci, cocci
NeisseriaNeisseria meningitismeningitis
FatalFatal blood or cerebrospinal fluid (CSF)blood or cerebrospinal fluid (CSF)
Respiratory dropletRespiratory droplet
SymptomsSymptoms
Sore throat, fever, headache, stiff neck,Sore throat, fever, headache, stiff neck,vomittingvomitting and convulsionand convulsion
Cause death within 6 hours of 1Cause death within 6 hours of 1stst symptomsymptom