Chapter1,Part2:TheMicrobialWorldandYou

Microbiology:AHistoricalPerspective

TheMicrobialWorldUnveiledbyMicroscopy 1600s:

RobertHooke:hisMicrographia wasfirsttoshowlifeunderthemicroscope;achievedonly30Xmagnification.

Antonie vanLeeuwenhoek:firsttoobservesinglecelledmicrobes(animalcules)usingmoresophisticatedmicroscope.

Thediscoveryofmicrobes wheredidtheyoriginate?

Spontaneousgeneration:

Whatisthis?

*CellTheory

FrancescoRediExperiment(1668)

RefutingSpontaneousGeneration:Air&VitalForces

JohnNeedham(1745):vitalforceinallmatterpreheatedbrothspouredintocoveredflasks becamefullofmicrobes

Claim:airrequiredforspontaneousgeneration

A B C

FlaskCresultrefutesthisclaim

Spallanzani (1760s): brothsheatedafter beingsealedinaflasknomicrobialgrowth.**counterargument:vitalforcealtered

NomaggotsinjarC,butwillmeatbepreserved?

Virchow&others(1850s):celltheory biogenesis ProofPasteursexperimentdisprovedabiogenesis:

Enter LouisPasteur

Pasteursflaskdesign(i.e.,swanneck)

Showedmicrobeswerepresentinmanynonlivingsources

*Aseptictechniquesdeveloped(heat,cottonplugs)

PasteursworkbegantheGoldenAgeofMicrobiology(18571914)*contributionsby Pasteur&RobertKoch werekeyinthisera

Pasteur: Metabolism&growth fermentation(Frenchwineindustry) Foodpreservation(Pasteurization)

GermTheoryofFermentation(seenextslide)

Hisidea:microbialactivitytransformsorganicmaterial;similarprocessformicrobesin/onplantsoranimals?Leadsto ??

Applytheory tomedicalprocedures: Ignaz Semmelweis (1847):observeddeclineinchildbedfever

(puerperalfever)linkedtohygienicpractices;useofantiseptic

JosephLister(1865):employeduseofantisepticagents(carbolicacid)totreatwoundsandsurgicalinstruments.

MedicalMicrobiology

Investigationofanthrax(Bacillusanthracis):e Establishedchainofinfection (transmissionofdisease)using Pureculturetheory:isolateasinglebacterialspeciesfromamixed

culture;establishpurecultureisolateisthecausativeagent.

RobertKoch(1870s):firsttoestablishscientificprinciplesfordetermining: Aspecificmicrobecausedaspecificdisease

Solidgrowthmedia:solidifyliquidgrowthmediumbyadditionofgelatin,lateragar.

Theconcept:

KochsPostulates

Dotheyapplytoalldiseases?

IsolationofBacillusanthracis,frominfectedcattle

Allowedforformulationofprinciplestoestablishacausativelinkbetweenthisisolateandanthrax.

Kochspostulatesremainaguidetodeterminingthemicrobediseaselink.

ImmunizationPreventsDisease Vaccinations:relyonattenuatedvirusor

bacteria(lessactiveform,lossofvirulence)

Basicprincipleofimmunization:

LadyMontagu(1700s):smallpox;inoculatewithmaterialfromsmallpoxpustules

EdwardJenner(1700s):cowpoxvaccinationtoprotectagainstsmallpox;safer howso?

Pasteur(1880s):firsttorecognizevalueofattenuatedpathogen;studyoffowlcholera&rabiesvaccine.

Cardinalruleofchemotherapy:killtheinfectingagent,notthepatient Syntheticdrugs:PaulErlichsmagicbullet(1910) salvarsan

treatmentforsyphilis;quinine;sulfadrugs.

Discoveryofantibiotics:naturallyoccurringamongmicrobes

Chemotherapy

Microbesfightback:antibioticresistance

Antimicrobialsv.Viraldiseases

AlexanderFleming(1929)&Penicillin(fromthemoldPenicillium notatum)

Definingwhatisconsideredamicrobe Typesofmicrobes

Prokaryotic:bacteria,archaea Eukaryotic:algae,protozoa,certainmolds/fungi(yeast) Viruses

Bacterialgenomes Microbialoriginsandevolution Classificationofmicrobes Impactofmicrobesonsociety

Ecology(Winogradski,Biejerinck) Biotechnology/Bioremediation Publichealth UnderstandingofDNA,proteinsynthesis&otherbasiclifeprocesses

Summary Part1

Historicalimportance(GoldenAgeofMicrobiology:1850stoearly1900s) Microscopy(Hooke,vanLeeuwenhoek)

Spontaneousgeneration

GermTheoryofFermentation

GermTheoryofDisease

WorkofPasteur&Koch

Immunization,vaccination(Jenner)

Chemotherapy Developmentofantibiotics(Erlich,Fleming)

Summary Part2