MicroorganismsandMicrobiology,Chapter1,Chapteroutline,1.1Whatisamicrobe?1.2TheimportanceofMicrobiology1.3Microbesinourlives1.4Thehistoryofmicrobiology1.5Importanteventsinthedevelopmentofmicrobiology,Concepts,Microorganismsareresponsibleformanyofthechangesobservedinorganicandinorganicmatter(e.g.,fermentationandthecarbon,nitrogenandsulfurcyclesthatoccurredinnature.Thedevelopmentofmicrobiologyasascientificdisciplinehasdependedontheavailabilityofthemicroscopeandtheabilitytoisolateandgrowpureculturesofmicroorganisms.Microbiologyisalargediscipline,whichhasagreatimpactonotherareasofbiologyandgeneralhumanwelfare,Thewordmicrobe(microorganism)isusedtodescribeanorganismthatissosmallthatcannotbeseenwithouttheuseofamicroscope.Viruses,bacteria,fungi,protozoaandsomealgaeareallincludedinthiscategory.,1.1Whatisamicrobe?,Ourworldispopulatedbyinvisiblecreaturestoosmalltobeseenwiththeunaidedeye.Theselifeforms,themicrobesormicroorganisms,maybeseenonlybymagnifyingtheirimagewithamicroscope.,Microbialworld,Organisms(living),Infectiousagents(non-living),Prokaryotes(unicellular),eukaryotes,viruses,viroids,prions,Eubacteria,Archaea,Algae(unicellularormulticellular),Fungi(unicellularormulticellular),Protozoa(unicellular),Other(multicellularorganisms),Mostofthebacteria,protozoa,andfungiaresingle-celledmicroorganisms,andeventhemulticelledmicrobesdonothaveagreatrangeofcelltypes.Virusesarenotevencells,justgeneticmaterialsurroundedbyaproteincoatandincapableofindependentexistence.,Thesizeandcelltypeofmicrobes,Thesizeandcelltypeofmicrobes,Microbesimpingeonallaspectsoflife,justafewofthesearelistedbelow:,Theenvironment,Medicine,Food,Biotechnology,Research,1.2Theimportanceofmicrobiology,TheenvironmentMedicineFoodBiotechnologyResearch,Pressheretocontinue,Microbesareresponsibleforthegeochemicalcycles.Theyarefoundinassociationwithplantsinsymbioticrelationships.Somemicrobesaredevastatingplantpathogens,butothersmayactasbiologicalcontrolagentsagainstdiseases.,Thedisease-causingabilityofsomemicrobesiswellknown.However,microorganismshavealsoprovideduswiththemeansoftheircontrolintheformofantibioticsandothermedicallyimportantdrugs.,Microbeshavebeenusedtoproducefood,frombrewingandwinemaking,throughcheeseproductionandbreadmaking,tothemanufactureofsoysauce.Butmicrobesarealsoresponsibleforfoodspoilage.,Traditionallymicrobeshavebeenusedtosynthesizeimportantchemicals.Theadventofgeneticengineeringtechniqueshasledtothecloningofpolypeptidesintomicrobes.,Microbeshavebeenusedasmodelorganismsfortheinvestigationofbiochemicalandgeneticalprocesses.Millionsofcopiesofthesamesinglecellcanbeproducedveryquicklyandgiveplentyofhomogeneousexperimentalmaterial.Mostpeoplehavenoethicalobjectionstoexperimentswiththesemicroorganisms.,1.3Microbesinourlives,MicroorganismsasDiseaseAgentsMicroorganismsandAgricultureMicroorganismsandtheFoodIndustryMicroorganisms,Energy,andtheEnvironmentMicroorganismsandtheFuture,BranchesofMicrobiology,Bacteriology,Protozoology,Parasitology,MicrobialMorphology,Mycology,Virology,PhycologyorAlgology,Microbialphysiology,Microbialtaxonomy,Microbialgenetics,Molecularbiology,Microbialecology,Thefutureofmicrobiologyisbright,Microbiologyisoneofthemostrewardingofprofessions,becauseitgivesitspractitionerstheopportunitytobeincontactwithalltheothernaturalscienceandthustocontributeinmanydifferentwaystothebettermentofhumanlife.,1.4Thehistoryofmicrobiology,Inthefieldofobservation,chancefavorsonlypreparedminds.-LouisPasteur,Thediscoveryofmicroorganisms,Thespontaneousgenerationconflict,Therecognitionofmicrobialroleindisease,Thediscoveryofmicrobialeffectsonorganicandinorganicmatter,Thedevelopmentofmicrobiologyinthiscentury,Thediscoveryofmicroorganisms,Thefirstpersontoaccuratelyobserveanddescribemicroorganisms,AntonyvanLeeuwenhock(1632-1723),ThefirstpersontoobserveanddescribemicroorganismswastheamateurmicroscopistAntonyvanleeuwenhoekofDelft,Holland.,Leeuwenhockmadehissimple,single-lensmicroscopewhichcouldamplifytheobjectbeingviewed50300times.Between1673-1723,hewroteaseriesofletterstotheRoyalSocietyofLondondescribingthemicrobesheobservedfromthesamplesofrainwater,andhumammouth.,Leeuwenhoeksdrawingsofbacteriafromthehumanmouth.,Adrawingofoneofthemicroscopesshowingthelensa;mountingpinb;andfocusingscrewscandd.,lens,Objectbeingviewed,adjusting,screws,Pasteurscontributions:,LouisPasteurworkinginhislaboratory,LouisPasteur(18221895),Pasteur(1857)demonstratedthatlacticacidfermentationisduetotheactivityofmicro-organismsPasteur(1861)conflictoverspontaneousgenerationbirthofmicrobiologyasasciencePasteur(1881)developedanthraxvaccinePasteurization,Spontaneousgenerationthatlivingorganismscoulddevelopfromnonlivingordecomposingmatter.,Thespontaneousgenerationconflict,Pasteursswanneckflasksusedinhisexperimentsonthespontaneousgenerationofmicroorganisms,Conclusion:Microorganismsarenotspontaneouslygeneratedfrominanimatematter,butareproducedbyothermicroorganisms,RobertKochinhislaboratory,Therecognitionofmicrobialroleindisease,RobertKoch(18431910),Kochsdemonstrationofspecialorganismscausespecialdiseases,Kochspostulates,Themicroorganismsmustbepresentineverycaseofthediseasebutabsentfromhealthyorganisms.,Thesuspectedmicroorganismsmustbeisolatedandgrowninapureculture.,Thediseasemustresultwhentheisolatedmicroorganismsisinoculatedintoahealthyhost.,Thesamemicroorganismsmustbeisolatedagainfromthediseasedhost,TheGoldenageofmicrobiology,Kochandpurecultures,FermentationandPasteurization,Germtheoryofdisease,Vaccination,Thediscoveryofmicrobialeffectsonorganicandinorganicmatter,TheRussianmicrobiologistWinograskydiscoveredthatsoilbacteriacouldoxidizeiron,sulfurandammoniatoobtainenergy,andalsoisolatednitrogenfixingbacteria.Beijerinckmadefundamentalcontributionstomicrobialecology.HeisolatedAzotobacterandRhizobium.,AlexanderFleming(1881-1955),SirAlexanderFlemingdiscoveredtheantibioticpenicillin.Hehadtheinsighttorecognizethesignificanceoftheinhibitionofbacterialgrowthinthevicinityofafungalcontaminant.,DateMicrobiologicalHistory1676LeeuwenhoekdiscoversanimalculesPasteurshowsthatlacticacidfermentationisduetoamicroorganismPasteurshowsthatmicroorganismsdonotarisebyspontaneousgeneration1867Listerpublisheshisworkonantisepticsurgery1869Miescherdiscoversnucleicacids1876-1877KochdemonstratesthatanthraxiscausedbyBacillusanthracisLaverandiscoversPlasmodium,thecauseofmalaria1881KochculturesbacteriaongelatinPasteurdevelopsanthraxvaccine,1.5Importanteventsinthedevelopmentofmicrobiology,1884KochspostulatesfirstpublishedMetchnikoffdescribesphagocytosisGramstaindeveloped1887Petridish(plate)developedbyRichardPetriBeijerinckisolatesrootnodulebacteriaBeijerinckprovesthatavirusparticlecausesthetobaccomosaicdisease1921Flemingdiscoverslysozyme1923FirsteditionofBergeysManual1928Griffithdiscoversbacterialtransformation1929FlemingdiscoverspenicillinRuskadevelopsfirsttransmissionelectronmicroscope1935Stanleycrystallizesthetobaccomosaicvirus,AveryshowsthatDNAcarriesinformationduringtransformationWaksmandiscoversstreptomycinWatsonandCrickproposethedoublehelixstructureforDNA1961-1966Cohenetaluseplasmidvectorstoclonegenesinbacteria1980Developmentofthescanningtunnelingmicroscope1983-1984ThepolymerasechainreactiondevelopedbyMullis1990Firsthumangene-therapytestingbegunDiscoveryofThiomargaritanamibiensis,thelargestknownbacteriumEscherichiacoligenomesequencedDiscoverythatVibriocholeraehastwoseparatechromosomes,1.HowdidPasteursfamousexperimentdefeatthetheoryofspontaneousgeneration?2.HowcanKochspostulatesprovecauseandeffectinadisease?3.Whowasthefirstpersontousesolidculturemediainmicrobiology?Whatadvantagesdosolidmediaofferforthecultureofmicroorganisms?,REVIEWQUESTIONS:,4.Whatistheenrichmentculturetechniqueandwhywasitausefulnewmethodinmicrobiology?5.WhenandhowAlexanderFlemingdiscoveredantibiotics?,1.Pasteursexperimentsonspontaneousgenerationwereofenormousimportancefortheadvanceofmicrobiology,havinganimpactonthemethodologyofmicrobiology,ideason(heoriginoflife,andthepreservationoffood,tonamejustafew.Explainbrieflyhowtheimpactofhisexperimentswasfeltoneac