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MicroorganismsandMicrobiologyChapter1Chapteroutline1.1Whatisamicrobe?1.2TheimportanceofMicrobiology1.3Microbesinourlives1.4Thehistoryofmicrobiology1.5ImportanteventsinthedevelopmentofmicrobiologyConcepts•Microorganismsareresponsibleformanyofthechangesobservedinorganicandinorganicmatter(e.g.,fermentationandthecarbon,nitrogenandsulfurcyclesthatoccurredinnature.•Thedevelopmentofmicrobiologyasascientificdisciplinehasdependedontheavailabilityofthemicroscopeandtheabilitytoisolateandgrowpureculturesofmicroorganisms.•Microbiologyisalargediscipline,whichhasagreatimpactonotherareasofbiologyandgeneralhumanwelfareThewordmicrobe(microorganism)isusedtodescribeanorganismthatissosmallthatcannotbeseenwithouttheuseofamicroscope.Viruses,bacteria,fungi,protozoaandsomealgaeareallincludedinthiscategory.1.1Whatisamicrobe?Ourworldispopulatedbyinvisiblecreaturestoosmalltobeseenwiththeunaidedeye.Theselifeforms,themicrobesormicroorganisms,maybeseenonlybymagnifyingtheirimagewithamicroscope.MicrobialworldOrganisms(living)Infectiousagents(non-living)Prokaryotes(unicellular)eukaryotesvirusesviroidsprionsEubacteriaArchaeaAlgae(unicellularormulticellular)Fungi(unicellularormulticellular)Protozoa(unicellular)Other(multicellularorganisms)Mostofthebacteria,protozoa,andfungiaresingle-celledmicroorganisms,andeventhemulticelledmicrobesdonothaveagreatrangeofcelltypes.Virusesarenotevencells,justgeneticmaterialsurroundedbyaproteincoatandincapableofindependentexistence.ThesizeandcelltypeofmicrobesMicrobeApproximaterangeofsizesCelltypeViruses0.01-0.25µmAcellularBacteria0.1-10µmProkaryoteFungi2µm-1mEukaryoteProtozoa2-1000µmEukaryoteAlgae1µm-severalmetersEukaryoteThesizeandcelltypeofmicrobesMicrobesimpingeonallaspectsoflife,justafewofthesearelistedbelow:TheenvironmentMedicineFoodBiotechnologyResearch1.2Theimportanceofmicrobiology•Theenvironment•Medicine•Food•Biotechnology•ResearchPressheretocontinueMicrobesareresponsibleforthegeochemicalcycles.Theyarefoundinassociationwithplantsinsymbioticrelationships.Somemicrobesaredevastatingplantpathogens,butothersmayactasbiologicalcontrolagentsagainstdiseases.Thedisease-causingabilityofsomemicrobesiswellknown.However,microorganismshavealsoprovideduswiththemeansoftheircontrolintheformofantibioticsandothermedicallyimportantdrugs.Microbeshavebeenusedtoproducefood,frombrewingandwinemaking,throughcheeseproductionandbreadmaking,tothemanufactureofsoysauce.Butmicrobesarealsoresponsibleforfoodspoilage.Traditionallymicrobeshavebeenusedtosynthesizeimportantchemicals.Theadventofgeneticengineeringtechniqueshasledtothecloningofpolypeptidesintomicrobes.Microbeshavebeenusedasmodelorganismsfortheinvestigationofbiochemicalandgeneticalprocesses.Millionsofcopiesofthesamesinglecellcanbeproducedveryquicklyandgiveplentyofhomogeneousexperimentalmaterial.Mostpeoplehavenoethicalobjectionstoexperimentswiththesemicroorganisms.1.3Microbesinourlives•MicroorganismsasDiseaseAgents•MicroorganismsandAgriculture•MicroorganismsandtheFoodIndustry•Microorganisms,Energy,andtheEnvironment•MicroorganismsandtheFutureBranchesofMicrobiologyBacteriologyProtozoologyParasitologyMicrobialMorphologyMycologyVirologyPhycologyorAlgologyMicrobialphysiologyMicrobialtaxonomyMicrobialgeneticsMolecularbiologyMicrobialecologyThefutureofmicrobiologyisbrightMicrobiologyisoneofthemostrewardingofprofessions,becauseitgivesitspractitionerstheopportunitytobeincontactwithalltheothernaturalscienceandthustocontributeinmanydifferentwaystothebettermentofhumanlife.1.4ThehistoryofmicrobiologyInthefieldofobservation,chancefavorsonlypreparedminds.------LouisPasteurThediscoveryofmicroorganismsThespontaneousgenerationconflictTherecognitionofmicrobialroleindiseaseThediscoveryofmicrobialeffectsonorganicandinorganicmatterThedevelopmentofmicrobiologyinthiscenturyThediscoveryofmicroorganismsThefirstpersontoaccuratelyobserveanddescribemicroorganismsAntonyvanLeeuwenhock(1632-1723)ThefirstpersontoobserveanddescribemicroorganismswastheamateurmicroscopistAntonyvanleeuwenhoekofDelft,Holland.Leeuwenhockmadehissimple,single-lensmicroscopewhichcouldamplifytheobjectbeingviewed50–300times.Between1673-1723,hewroteaseriesofletterstotheRoyalSocietyofLondondescribingthemicrobesheobservedfromthesamplesofrainwater,andhumammouth.Leeuwenhoek’sdrawingsofbacteriafromthehumanmouth.Adrawingofoneofthemicroscopesshowingthelensa;mountingpinb;andfocusingscrewscandd.lensObjectbeingviewedadjustingscrewsPasteur’scontributions:LouisPasteurworkinginhislaboratoryLouisPasteur(1822–1895)•Pasteur(1857)demonstratedthatlacticacidfermentationisduetotheactivityofmicro-organisms•Pasteur(1861)conflictoverspontaneousgeneration–birthofmicrobiologyasascience•Pasteur(1881)developedanthraxvaccine•PasteurizationSpontaneousgeneration–thatlivingorganismscoulddevelopfromnonlivingordecomposingmatter.ThespontaneousgenerationconflictPasteur’sswanneckflasksusedinhisexperimentsonthespontaneousgenerationofmicroorganismsConclusion:Microorganismsarenotspontaneouslygeneratedfrominanimatematter,butareproducedbyothermicroorganismsRobertKochinhislaborato