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History History of of

MicrobiologyMicrobiology

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Created By:Created By:

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Topic DiscussedTopic Discussed� Cells and cell theoryCells and cell theory� Microbes and Germ Microbes and Germ

TheoryTheory� Classic Age of Classic Age of

MicrobiologyMicrobiology– FermentationFermentation– PasteurizationPasteurization� ………………??????

Filename : Siam.ppt

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MicrobiologyMicrobiology� MicrobiologyMicrobiology is the study of is the study of

microorganisms usually less than 1mm in microorganisms usually less than 1mm in diameter which requires some form of diameter which requires some form of magnification( Microscope) to be seen magnification( Microscope) to be seen clearly.clearly.– Examples:Examples:

� VirusesViruses� BacteriaBacteria� FungiFungi� AlgaeAlgae� Protozoa'sProtozoa's

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““History History of of

Microbiology”Microbiology”

Early Observations & Early Observations & ExperimentsExperiments

Robert Hooke: cellsRobert Hooke: cellsLeeuweenhoek: microbesLeeuweenhoek: microbes

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� Robert Hook-Robert Hook- (1635-(1635-1703) 1703) Englishman, used Englishman, used a primitive compound a primitive compound (two magnifying lenses)(two magnifying lenses)

� microscope, reported microscope, reported that life’s smallest units that life’s smallest units were little boxes – were little boxes – CellsCells , his work, his work

� started the process of started the process of the development of the the development of the Cell theory Cell theory of lifeof life

First illustrated book on First illustrated book on microscopymicroscopy

MicrographiaMicrographia

Hook’s microscopeHook’s microscope

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The Cell TheoryThe Cell Theory� All organisms composed of one or All organisms composed of one or

more cellsmore cells� Cells are smallest l iving thingsCells are smallest l iving things� Cells arise only from previously Cells arise only from previously

existing cellsexisting cells� Thus: al l organisms are descendents Thus: al l organisms are descendents

of the first cellsof the first cells

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Anton Van LeeuwenhoekAnton Van Leeuwenhoek First person to see bacteriaFirst person to see bacteria Single lens microscope Single lens microscope

� First to observe living First to observe living microbesmicrobes

� His single-lens magnified His single-lens magnified 50-300X magnification50-300X magnification

� Between 1674-1723 he Between 1674-1723 he wrote series of papers wrote series of papers describing his describing his observations of bacteria, observations of bacteria, algae, protozoa, and fungi algae, protozoa, and fungi (Animalcules)(Animalcules)

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Early Compound Microscope

� beautifully crafted but had severe chromatic distortion

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Spontaneous GenerationSpontaneous Generation� Biogenesis vs. AbiogenesisBiogenesis vs. Abiogenesis

� Aristot leAristot le

� Jan Baptista van Helmont (1580-1644)Jan Baptista van Helmont (1580-1644)

� Francisco Redi (1626-1697)Francisco Redi (1626-1697)

� John T. Needham (1713-1781)John T. Needham (1713-1781)

� Lazzaro Spallanzani (1729-1799)Lazzaro Spallanzani (1729-1799)

� Theodor Schwann (1810-1882)Theodor Schwann (1810-1882)

� Louis Pasteur (1822-1895)Louis Pasteur (1822-1895)

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Biogenesis Biogenesis vs. vs.

AbiogenesisAbiogenesis

� Biogenesis - development of life from Biogenesis - development of life from preceding life formspreceding life forms

� Abiogenesis - life arises from inorganic Abiogenesis - life arises from inorganic or non-living materialsor non-living materials

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AristotleAristotle� First to record possible routes to life.First to record possible routes to life.� He saw beings as arising in one of three ways, from He saw beings as arising in one of three ways, from

sexual reproduction, asexual reproduction or sexual reproduction, asexual reproduction or nonliving matter.nonliving matter.

� Observable that aphids arise from the dew on plants, Observable that aphids arise from the dew on plants, fleas from putrid matter, and mice from dirty hayfleas from putrid matter, and mice from dirty hay

� This belief remained unchallenged for more than two This belief remained unchallenged for more than two thousand years.thousand years.

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Jan Baptista van HelmontJan Baptista van Helmont (1580-1644) (1580-1644)

� Reported in late 1500’s that barley grains and Reported in late 1500’s that barley grains and old shirts left in a corner would spontaneously old shirts left in a corner would spontaneously give rise to micegive rise to mice

� Claimed as evidence that supported Claimed as evidence that supported spontaneous generation or abiogenesisspontaneous generation or abiogenesis

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Francisco Redi (1626-1697)Francisco Redi (1626-1697)� Set up controlled experiment to test idea of Set up controlled experiment to test idea of

spontaneous generation with respect to spontaneous generation with respect to maggots appearing on rotting meatmaggots appearing on rotting meat– open jar with meatopen jar with meat– screened jar with meatscreened jar with meat– sealed jar with meatsealed jar with meat

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von Helmutopen

screened

sealed

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John T. Needham John T. Needham (1713-1781)(1713-1781)

� Flies do not arise spontaneously but the Flies do not arise spontaneously but the “animalcules” described by van Leeuwenhoek “animalcules” described by van Leeuwenhoek mustmust

� In 1748 Needham boiled mutton broth, In 1748 Needham boiled mutton broth, stoppered and noted that flask becam turbidstoppered and noted that flask becam turbid

� Argued that the turbidity, which included Argued that the turbidity, which included many “animalcules” must have arisen many “animalcules” must have arisen spontaneouslyspontaneously

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Lazzaro SpallanzaniLazzaro Spallanzani(1729-1799)(1729-1799)

� Repeated Needham’s experimentsRepeated Needham’s experiments� Used flasks that were sealed by melting the Used flasks that were sealed by melting the

glass rather than with a corkglass rather than with a cork� Found that if sealed properly, flasks boiled 45 Found that if sealed properly, flasks boiled 45

minutes would remain sterile thus refuting minutes would remain sterile thus refuting Needham’s conclusionsNeedham’s conclusions

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Theodor Schwann Theodor Schwann (1810-1882)(1810-1882)

� An argument An argument against Spallanzani against Spallanzani experiments is that experiments is that they excluded airthey excluded air

� Constructed Constructed apparatus to apparatus to sterilize air coming sterilize air coming into flaskinto flask

� Results supported Results supported biogenesisbiogenesis

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Theodor Schwann Theodor Schwann (1810-1882)(1810-1882)

Apparatus used by Schwann Apparatus used by Schwann The central flask, which is The central flask, which is being rendered sterile by being rendered sterile by heating contains the heating contains the infusion. Air is passed infusion. Air is passed through it from the heated through it from the heated coil on right. The flask at coil on right. The flask at left is a mercury trap left is a mercury trap through which air escapes through which air escapes after passing through the after passing through the central flask.central flask.

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Louis Pasteur Louis Pasteur (1822-1895)(1822-1895)

� Looked at air which had Looked at air which had been filteredbeen filtered

� Developed swan neck Developed swan neck flask to deal with heated flask to deal with heated air problemair problem

� Looked at frequency of Looked at frequency of occurrence of occurrence of contaminated flaskscontaminated flasks

� Settled controversySettled controversy

““Father of bacteriology and Father of bacteriology and immunology”immunology”

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Louis Pasteur (1822-1895)Louis Pasteur (1822-1895)

An example of the An example of the swan-necked flaskswan-necked flask

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Golden Age of MicrobiologyGolden Age of Microbiology

� FermentationFermentation� PasteurizationPasteurization� Germ TheoryGerm Theory

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FermentationFermentation� Vintners thought sugar Vintners thought sugar chemicallychemically

converted to alcohol in airconverted to alcohol in air� Pasteur, a chemist, was asked to help Pasteur, a chemist, was asked to help � Discovered Discovered

– Yeast convert sugars to alcoholYeast convert sugars to alcohol– Bacteria change alcohol to vinegarBacteria change alcohol to vinegar

� Fermentation was biological processFermentation was biological process

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PasteurizationPasteurization� Pasteur connected food Pasteur connected food

spoilage and microbesspoilage and microbes� Pasteurization: Destroy Pasteurization: Destroy

microbes that cause microbes that cause spoilage by heatspoilage by heat– Beer, wine, milkBeer, wine, milk

� Critical to development Critical to development of Germ theoryof Germ theory

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Pasteur’s Original FlasksPasteur’s Original Flasks

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Germ Theory of DiseaseGerm Theory of Disease� Observation on causative agents of Observation on causative agents of

potato blight and diseases of silkworms potato blight and diseases of silkworms led to hypothesisled to hypothesis

� Formalized through work of Pasteur Formalized through work of Pasteur and Koch (and others) led to theory that and Koch (and others) led to theory that germs or microorganisms may cause germs or microorganisms may cause diseasedisease

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Germ Theory of DiseaseGerm Theory of Disease� Robert Koch first Robert Koch first

developed developed relationship between relationship between microorganisms and microorganisms and diseasedisease

� Developed Koch’s Developed Koch’s Postulates for Postulates for testing relationshiptesting relationship

� Discovered cause of Discovered cause of anthrax and anthrax and tuberculosistuberculosis

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Germ Theory of DiseaseGerm Theory of Disease� Koch’s Postulates:Koch’s Postulates:

– Same microorganism must be observed in Same microorganism must be observed in every instance of diseaseevery instance of disease

– Organism must be isolated from diseased Organism must be isolated from diseased host and grown in pure culturehost and grown in pure culture

– Specific disease must be reproduced when Specific disease must be reproduced when pure culture is reintroduced into hostpure culture is reintroduced into host

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????????

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Technological advances have Technological advances have resulted in the development of resulted in the development of studies instudies in

– Agricultural Agricultural microbiologymicrobiology– Aquatic Aquatic microbiologymicrobiology– IndustrialIndustrial microbiology microbiology– Medical Medical microbiologymicrobiology– SpaceSpace microbiology microbiology– EnvironmentalEnvironmental microbiology microbiology

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