03 bacterial growth

8/7/2019 03 Bacterial Growth

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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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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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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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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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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

03 bacterial growth

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