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Chapter 1The Main Themes of MicrobiologyCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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MicrobiologyThe study of organisms too small to be seen without magnification
Microorganisms include:BacteriaVirusesFungiProtozoa Helminths (worms) Algae*
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Microbiological Endeavors*Jack Dykinga, USDA/ARSPhoto courtesy of Sartorius Stedim BiotechCDCJames Gathany/CDC
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Origins of MicroorganismsBacteria-like organisms have existed on earth for about 3.5 billion yearsProkaryotes (pre-nucleus): Simple cells Eukaryotes (true nucleus): Complex cellsCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or displayProkaryotesappeared.Probableorigin ofearth15 billionyears ago4 billionyears ago3 billionyears ago2 billionyears ago1 billionyears agoPresenttimeEukaryotesappeared.Reptilesappeared.Cockroaches,termitesappeared.Mammalsappeared.Humansappeared.*
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Microbial Structure Two cell lines Prokaryote microscopic, unicellular organisms, lack nuclei and membrane-bound organellesEukaryote unicellular (microscopic) and multicellular, nucleus and membrane-bound organellesViruses - Acellular, parasitic particles composed of a nucleic acid and protein
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or displayCell membraneNucleusMitochondriaRibosomesCellmembraneCell wallFlagellumFlagellumChromosomeProkaryoticEukaryoticCapsidEnvelopeAIDS virusBacterial virusNucleicacidRibosomes(a) Cell Types(b) Virus Types*
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Janice Carr/CDC Tom Volk Charles Krebs PhotographyCDC Yuuji Tsukii, Protist Information ServerCDCCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Reproductive sporesBacteria: Mycobacterium tuberculosis, arod-shaped cell (15,500x).Fungi: Thamnidium, a filamentousfungus (400x)Algae: desmids, Spirogyra filament, and diatoms(golden cells) (500x).A single virus particleVirus: Herpes simplex, cause of coldsores (100,000x).Protozoa: A pair of Vorticella (500x), stalked cellsthat feed by means of a whirling row of cilia.Helminths: Cysts of the parasitic roundworm,Trichinella spiralis (250x) embedded in muscle.Microbial Diversity: 6 Types of Microbes*
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Microbial Dimensions10 nm100 nm200 nm10 mmCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.LouseReproductive structureof bread moldMacroscopicMacroscopic(1 Angstrom)RangeofhumaneyeRangeof light microscopeRange of electron microscopeRequire special microscopes1 nm1 mm100 mmAmino acid (small molecule)Hydrogen atomDiameter of DNALarge proteinFlagellumPoliovirusAIDS virusMycoplasma bacteriaRickettsia bacteriaRod-shaped bacteria(Escherichia coli)Red blood cellMost bacteria fall between 1 to 10 mmin sizeAmoebaWhite blood cellCoccus-shaped bacteria (Staphylococcus)Poxvirus0.1 nmColonial alga(Pediastrum)Hepatitis B virusMetric ScaleLog10 of meters3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 121,000100101.0 00,00,00,00Angstrom ( )kilometer (km)hektometer (hm)dekameter (dam)meter (m)decimeter (dm)centimeter (cm)millimeter (mm)micrometer (mm)nanometer (nm)picometer (pm)Nucleus0001 mm*
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Microbes in Energy & Nutrient FlowThe flow of energy and food through the earths ecosystems
Photosynthesis: Light fueled conversion of carbon dioxide to organic material
Decomposition: Breakdown of dead matter and wastes into simple compounds*
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Concept Check:Which of the following does NOT describe a fungus?
A. Contains a nucleus Has 80S Ribosomes Useful in Decomposition Is photosynthetic
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Human Use of MicroorganismsBiotechnology: Production of foods, drugs, and vaccines using living organisms
Genetic engineering: Manipulating the genes of organisms to make new products
Bioremediation: Using living organisms to remedy an environmental problem*
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Lifestyles of MicroorganismsMajority live a free existence, are relatively harmless and often beneficial
Some microorganisms have close associations with other organismsParasites live on or in the body of another organism called the host and it damages the host.
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Microbes & Infectious DiseasesPathogens: Microbes that do harm
Nearly 2,000 different microbes cause diseases
10 B new infections/year worldwide
12 M deaths from infections/year worldwide*MalariaDiarrheal diseases (cholera, dysentery, typhoid)AIDS26%18%17.5%11%9%7%5%Tetanus 2.5%Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.MeaslesHepatitisBTuberculosisRespiratory infections (pneumonia, influenza)Parasitic diseases 2.5%Miscellaneous 1.5%
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Top Causes of Death in the United States and Worldwide*
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Historical Foundations of MicrobiologyThousands of microbiologists over 300 years
Prominent discoveries include:MicroscopyScientific methodDevelopment of medical microbiology Microbiology techniques
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Spontaneous Generation Spontaneous Generation is an early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc.)
Louis Pasteur eventually disproved spontaneous generation and proved the Theory of Biogenesis - the idea that living things can only arise from other living things
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*Antonie van Leeuwenhoek (1632-1723)Dutch linen merchant
First to observe living microbes
Single-lens magnified up to 300X
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*Leeuwenhoeks Work Kathy Park Talaro/Visuals Unlimited Kathy Park Talaro/Visuals UnlimitedCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.LensSpecimen holderHandleFocus screw
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Scientific MethodApproach taken by scientists to explain a certain natural phenomenonForm a hypothesis - a tentative explanation that can be supported or refutedDeductive approach If, then.A lengthy process of experimentation, analysis, and testing either supports or refutes the hypothesisResults must be published and repeated by other investigators.If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory.If evidence of a theory is so compelling that the next level of confidence is reached, it becomes a Law or principle.*
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Concept Check:A Scientific Theory has little or no evidence to support it and could be best described as a best guess.
A. True B. False
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Discovery of Spores and SterilizationJohn Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes.Cohn determined these forms to be heat-resistant bacterial endospores.
Sterility requires the elimination of all life forms including endospores and viruses.*
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Using the Scientific Method to Investigate Bacterial Endospores*Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Additional tests show that endosporeshave thick coverings and protective featuresand that endospores are known to surviveover millions of years.Cells withoutendospores areordinary bacteria,fungi, animal cells.Endosporesof certainbacteriaBacterial endosporesare the most resistantof all cells on earth.HypothesisPredictionsTestingTheory/PrincipleEndosporesEndospores are the onlycells consistently capable ofsurviving a wide range ofdestructive environmentalconditions. In order tosterilize, these cells must beeliminated.If hypothesis is true,endospores can surviveextreme conditionssuch as:Compare endospore formers to non-endospore microbes.Survival ofendospore formerSurvival ofnon-endospore former temperature (boiling)................................+............................./+* radiation (ultraviolet).................................+.............................. lack of water (drying)................................+............................./+ chemicals.................................................+............................./+ (disinfectants) *Only 1 out of 4 cell types survives.
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Development of Aseptic TechniquesThe human body is a source of infectionDr. Oliver Wendell Holmes observed that mothers of home births had fewer infections than those who gave birth in hospitals
Dr. Ignaz Semmelweis correlated infections with physicians coming directly from the autopsy room to the maternity ward
Joseph Lister introduced aseptic techniques to reduce microbes in medical settings and prevent wound infectionsInvolved disinfection of hands using chemicals prior to surgeryUse of heat for sterilization
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The Germ Theory of DiseaseMany diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.
Two major contributors: Louis Pasteur and Robert Koch
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*Louis Pasteur (1822-1895)Showed microbes caused fermentation and spoilage
Disproved spontaneous generation of microorganisms
Developed pasteurization
Demonstrated what is now known as Germ Theory of Disease
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*Robert Koch (1843-1910)Established Kochs postulates - a sequence of experimental steps that verified the germ theory
Identified cause of anthrax, TB, and cholera
Developed pure culture methods
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TaxonomyTaxonomy: organizing, classifying, and naming living thingsFormal system originated by Carl von Linn
Concerned with: Classification orderly arrangement of organisms into groupsNomenclature assigning namesIdentification determining and recording traits of organisms for placement into taxonomic schemes
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Levels of ClassificationDomain - Archaea, Bacteria, & EukaryaKingdomPhylum or DivisionClass OrderFamilyGenusSpecies*
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Sample Taxonomy*Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Domain: Eukarya (All eukaryotic organisms)Kingdom: AnimaliaPhylum: ChordataClass: MammaliaOrder: PrimatesFamily: HominoideaGenus: HomoSpecies: sapiensSea squirtSea starLemur(a)Domain: Eukarya (All eukaryotic organisms)Kingdom: Protista Includes protozoa and algaePhylum: Ciliophora Only protozoa with ciliaClass: Hymenostomea Single cells with regular rows of cilia; rapid swimmersFamily: Parameciidae Cells rotate while swimming and have oral grooves.Genus: Paramecium Pointed, cigar-shaped cells with macronuclei and micronucleiSpecies: caudatum Cells cylindrical, long, and pointed at one end(b)Order: Hymenostomatida Elongate oval cells with cilia in the oral cavity
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Concept Check:Organisms in the same Family must also be in the same Class.
A. True B. False
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Assigning Specific NamesBinomial (scientific) nomenclature
Gives each microbe 2 names:Genus - capitalizedspecies - lowercase
Both italicized or underlinedStaphylococcus aureus (S. aureus)
Inspiration for names is extremely varied and often imaginative!
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The Origin and Evolution of MicroorganismsPhylogeny: natural relatedness between groups of organisms
EvolutionAll new species originate from preexisting speciesClosely related organism have similar features because they evolved from common ancestral forms
Evolution usually progresses toward greater complexity*
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Three Domains of LifeBacteria - true bacteria
Archaea - odd bacteria that live in extreme environments, high salt, heat, etc.
Eukarya - have a nucleus and organelles*Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Earliest cellEarly eukaryotesMONERANSPROTISTSFUNGIPLANTSANIMALSAngiospermsGymnospermsSeed plantsFernsMossesYeastsClub fungiMoldsChordatesArthropodsEchinodermsNematodesAnnelidsMollusksFlatwormsKingdom (Myceteae)Kingdom (Plantae)Kingdom (Protista)Kingdom MoneraSpongesAmoebasApicomplexansFlagellatesSlime moldsCiliatesGreen algaeRed algaeBrown algaeDiatomsArchaeaBacteriaDinoflagellatesFirst multicellular organisms appeared 0.6 billion years ago.First cells appeared 34 billion years ago.Kingdom (Animalia)5 kingdoms2 cell typesFirst eukaryotic cells appeared 62 billion years ago.PROKARYOTESEUKARYOTES
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The Evolutionary Relationships Between Earths Inhabitants*Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.KingdomsPlantaeAnimaliaFungiProtistaDomain BacteriaCyanobacteriaChlamydiasSpirochetesGram-positivebacteriaEndosporeproducersGram-negativebacteriaDomain ArchaeaMethaneproducersProkaryotesthat live inextreme saltProkaryotesthat live inextreme heatDomain EukaryaEukaryotesAncestral Cell Line (first living cells)
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Concept Check:Organisms in the Domain Archaea have more DNA sequence similarity to
A. Escherichia coli which is in the Domain Bacteria B. Humans which are in the Domain EukaryaC. Archaea have no DNA sequence similarity to any other organism*
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