Microbiology: A Microbiology: A Systems Approach, 2Systems Approach, 2ndnd

ed.ed.Chapter 1: The Main Themes of Chapter 1: The Main Themes of

MicrobiologyMicrobiology

1.1 The Scope of Microbiology1.1 The Scope of Microbiology

MicrobiologyMicrobiology: The study of living things : The study of living things too small to be seen without magnificationtoo small to be seen without magnification MicroorganismsMicroorganisms or or microbesmicrobes- these - these

microscopic organismsmicroscopic organisms Commonly called “germs, viruses, agents…” Commonly called “germs, viruses, agents…”

but not all cause disease and many more are but not all cause disease and many more are useful or essential for human lifeuseful or essential for human life

Major Groups of Major Groups of MicroorganismsMicroorganisms

BacteriaBacteria, , algaealgae, , protozoaprotozoa, , helmintheshelminthes, , and and fungifungi

VirusesViruses- noncellular, parasitic, protein-- noncellular, parasitic, protein-coated genetic elements that can infect all coated genetic elements that can infect all living things, including other living things, including other microorganismsmicroorganisms

Branches of MicrobiologyBranches of Microbiology Agricultural microbiologyAgricultural microbiology BiotechnologyBiotechnology Food, dairy, and aquatic microbiologyFood, dairy, and aquatic microbiology Genetic engineering and recombinant DNA Genetic engineering and recombinant DNA

technologytechnology Public health microbiology and Public health microbiology and

epidemiologyepidemiology ImmunologyImmunology Many, many moreMany, many more

Emerging Areas of MicrobiologyEmerging Areas of Microbiology

GeomicrobiologyGeomicrobiology Marine microbiologyMarine microbiology AstromicrobiologyAstromicrobiology

1.2 The Impact of Microbes on 1.2 The Impact of Microbes on Earth: Small Organisms with a Earth: Small Organisms with a

Giant EffectGiant Effect Microorganisms have a profound influence Microorganisms have a profound influence

on all aspects of the earth and its residentson all aspects of the earth and its residents Bacterial-like organisms in the fossil record Bacterial-like organisms in the fossil record

as far back as 3.5 billion years ago as far back as 3.5 billion years ago ((prokaryotesprokaryotes- organisms without a true - organisms without a true nucleus)nucleus)

2 billion years later, 2 billion years later, eukaryoteseukaryotes (organisms with a true nucleus) emerged(organisms with a true nucleus) emerged

Figure 1.1

Ubiquity of MicroorganismsUbiquity of Microorganisms Found nearly everywhereFound nearly everywhere Occur in large numbersOccur in large numbers Live in places many other organisms Live in places many other organisms

cannotcannot

Figure 1.2

Microbial Involvement in Energy Microbial Involvement in Energy and Nutrient Flowand Nutrient Flow

Bacteria conducted Bacteria conducted photosynthesisphotosynthesis before plants appearedbefore plants appeared Anoxygenic photosynthesisAnoxygenic photosynthesis Oxygenic photosynthesisOxygenic photosynthesis

Biological Biological decompositiondecomposition and nutrient and nutrient recyclingrecycling

1.3 Human Use of 1.3 Human Use of MicroorganismsMicroorganisms

Humans have been Humans have been using microorganisms using microorganisms for thousands of yearsfor thousands of years Baker’s and brewer’s Baker’s and brewer’s

yeastyeast CheesesCheeses Moldy bread on woundsMoldy bread on wounds

Figure 1.3

Biotechnology and Biotechnology and BioremediationBioremediation

BiotechnologyBiotechnology- when humans manipulate - when humans manipulate microorganisms to make products in an industrial microorganisms to make products in an industrial settingsetting Genetic engineeringGenetic engineering- create new products and - create new products and

genetically modified organisms (GMOs)genetically modified organisms (GMOs) Recombinant DNA technologyRecombinant DNA technology- allows microbes to be - allows microbes to be

engineered to synthesize desirable proteins (i.e. drugs, engineered to synthesize desirable proteins (i.e. drugs, hormones, and enzymes)hormones, and enzymes)

BioremediationBioremediation- introducing microbes in to the - introducing microbes in to the environment to restore stability or clean up toxic environment to restore stability or clean up toxic pollutantspollutants Oil spillsOil spills Chemical spillsChemical spills Water and sewage treatmentWater and sewage treatment

1.4 Infectious Diseases and the 1.4 Infectious Diseases and the Human ConditionHuman Condition

PathogensPathogens- disease-causing organisms- disease-causing organisms

Figure 1.4

Worldwide Infectious DiseasesWorldwide Infectious Diseases Increasing number of emerging diseases Increasing number of emerging diseases

(SARS, AIDS, hepatitis C, viral encephalitis)(SARS, AIDS, hepatitis C, viral encephalitis) Other diseases previously not linked to Other diseases previously not linked to

microorganisms now are (gastric ulcers, microorganisms now are (gastric ulcers, certain cancers, schizophrenia, multiple certain cancers, schizophrenia, multiple sclerosis, obsessive compulsive disorder, sclerosis, obsessive compulsive disorder, coronary artery disease)coronary artery disease)

Increasing number of drug resistant strainsIncreasing number of drug resistant strains

1.5 The General Characteristics of 1.5 The General Characteristics of MicroorganismsMicroorganisms

Cellular OrganizationCellular Organization Prokaryotic vs. eukaryotic cellsProkaryotic vs. eukaryotic cells

• Prokaryotic cells are about 10 times smaller than Prokaryotic cells are about 10 times smaller than eukaryotic cellseukaryotic cells

• Prokaryotic cells lack many cell structures such as Prokaryotic cells lack many cell structures such as organellesorganelles

• All prokaryotes are microorganisms, but only some All prokaryotes are microorganisms, but only some eukaryotes areeukaryotes are

Figure 1.5

VirusesViruses Not independently living cellular Not independently living cellular

organismsorganisms Much simpler than cells- Much simpler than cells-

basically a small amount of basically a small amount of DNA or RNA wrapped in DNA or RNA wrapped in protein and sometimes by a protein and sometimes by a lipid membranelipid membrane

Individuals are called a Individuals are called a virus virus particleparticle or or virionvirion

Depend on the infected cell’s Depend on the infected cell’s machinery to multiply and machinery to multiply and dispersedisperse

Microbial DimensionsMicrobial Dimensions

Figure 1.7

Lifestyles of MicroorganismsLifestyles of Microorganisms Most live a free existence (in soil or water, for example)Most live a free existence (in soil or water, for example) Some are Some are parasitesparasites

Figure 1.6

1.6 The Historical Foundations of 1.6 The Historical Foundations of MicrobiologyMicrobiology

Key to the study of microorganisms was the Key to the study of microorganisms was the development of the development of the microscopemicroscope

Earliest record of microbes was from the Earliest record of microbes was from the work of work of Robert HookeRobert Hooke in the 1660s in the 1660s

The most careful observations of microbes The most careful observations of microbes was possible after was possible after Antonie van Antonie van LeeuwenhoekLeeuwenhoek created the single-lens created the single-lens microscopemicroscope Known as the father of bacteriology and Known as the father of bacteriology and

protozoologyprotozoology

Figure 1.9

Establishment of the Establishment of the Scientific Scientific MethodMethod

Early scientists tended to explain natural phenomena Early scientists tended to explain natural phenomena by a mixture of belief, superstition, and argumentby a mixture of belief, superstition, and argument

During the 1600s, true scientific thinking developedDuring the 1600s, true scientific thinking developed From that, the development of the scientific methodFrom that, the development of the scientific method

Formulate a Formulate a hypothesishypothesis Most use the Most use the deductive approachdeductive approach to apply the scientific to apply the scientific

methodmethod Experimentation, analysis, and testing leads to Experimentation, analysis, and testing leads to

conclusionsconclusions Either support or refute the hypothesisEither support or refute the hypothesis

Hypotheses can eventually become theoriesHypotheses can eventually become theories Theories can eventually become laws or principlesTheories can eventually become laws or principles

Figure 1.10

The Development of Medical The Development of Medical MicrobiologyMicrobiology

The Discovery of Spores and SterilizationThe Discovery of Spores and Sterilization Louis PasteurLouis Pasteur- worked with infusions in the mid-- worked with infusions in the mid-

1800s1800s John TyndallJohn Tyndall- showed evidence that some - showed evidence that some

microbes have very high heat resistance and are microbes have very high heat resistance and are difficult to destroydifficult to destroy

Ferdinand CohnFerdinand Cohn- spores and sterilization- spores and sterilization The Development of Aseptic TechniquesThe Development of Aseptic Techniques

Physicians and scientist began to suspect that Physicians and scientist began to suspect that microorganisms could cause diseasemicroorganisms could cause disease

Joseph ListerJoseph Lister- introduced - introduced aseptic techniqueaseptic technique

The Discovery of The Discovery of Pathogens and the Pathogens and the Germ Theory of Germ Theory of DiseaseDisease Louis PasteurLouis Pasteur

• PasteurizationPasteurization• The Germ Theory of The Germ Theory of

DiseaseDisease Robert KochRobert Koch

• Koch’s postulatesKoch’s postulates- - verified the germ theoryverified the germ theory

Figure 1.11

1.7 Taxonomy: Naming, 1.7 Taxonomy: Naming, Classifying, and Identifying Classifying, and Identifying

MicroorganismsMicroorganisms MicrobialMicrobial nomenclaturenomenclature- naming - naming

microorganismsmicroorganisms TaxonomyTaxonomy- classifying living things- classifying living things

Originated over 250 years ago with the work Originated over 250 years ago with the work of Carl von Linnéof Carl von Linné

IdentificationIdentification- discovering and recording - discovering and recording the traits of organisms so they can be the traits of organisms so they can be named and classifiednamed and classified

Levels of ClassificationLevels of Classification

Figure 1.12

Assigning Specific NamesAssigning Specific Names A standardized nomenclature allows scientists A standardized nomenclature allows scientists

from all over the world to exchange informationfrom all over the world to exchange information The The binomial system of nomenclaturebinomial system of nomenclature

The generic (genus) name followed by the species The generic (genus) name followed by the species namename

Generic part is capitalized, species is lowercaseGeneric part is capitalized, species is lowercase Both are italicized or underlined if italics aren’t Both are italicized or underlined if italics aren’t

availableavailable Staphylococcus aureusStaphylococcus aureus

The Origin and Evolution of The Origin and Evolution of MicroorganismsMicroorganisms

PhylogenyPhylogeny- the degree of relatedness between - the degree of relatedness between groups of living thingsgroups of living things

Based on the process of Based on the process of evolutionevolution- hereditary - hereditary information in living things changes gradually information in living things changes gradually through time; these changes result in structural through time; these changes result in structural and functional changes through many generationsand functional changes through many generations Two preconceptions:Two preconceptions:

• All new species originate from preexisting speciesAll new species originate from preexisting species• Closely related organisms have similar features because Closely related organisms have similar features because

they evolved from a common ancestorthey evolved from a common ancestor Phylogeny usually represented by a tree- showing Phylogeny usually represented by a tree- showing

the divergent nature of evolutionthe divergent nature of evolution

Figure 1.13

Figure 1.14