Ch 01 Lecture Presentation

8/10/2019 Ch 01 Lecture Presentation

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2012 Pearson Education Inc.

Lecture prepared by Mindy Miller-KittrellNorth Carolina State University

Chapter 1

A Brief

History of

Microbiology


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The Early Years of Microbiology

What Does Life Really Look Like?

Antoni van Leeuwenhoek (Dutch)

Began making and using simple microscopes

Often made a new microscope for each specimen

Examined water and visualized tiny animals, fungi,algae, and single-celled protozoa: animalcules

By end of 19th century, these organisms were called

microorganisms



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Figure 1.1 Antoni van Leeuwenhoek


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Figure 1.2 Reproduction of Leeuwenhoeks microscope

Specimen holderLens


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Figure 1.3 The microbial world


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How Can Microbes Be Classified? Carolus Linnaeus developed taxonomic system

for grouping similar organisms together

Leeuwenhoeks microorganisms grouped into sixcategories:

Bacteria

Archaea

Fungi Protozoa

Algae

Small multicellular animals



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Bacteria and Archaea

Unicellular and lack nuclei

Much smaller than eukaryotes

Found everywhere there is sufficient moisture Reproduce asexually

Two kinds

Bacteriacell walls contain peptidoglycan

Archaeacell walls composed of polymersother than peptidoglycan



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Figure 1.4 Cells of the bacterium Streptococcus

Nucleus of

eukaryotic cheek cellProkaryotic

bacterial cells


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Fungi

Eukaryotic(have membrane-bound nucleus)

Obtain food from other organisms

Possess cell walls Include

Moldsmulticellular; grow as long filaments;reproduce by sexual and asexual spores

Yeastsunicellular; reproduce by budding orsexual spores



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Figure 1.5 Fungi-overview


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Protozoa

Single-celled eukaryotes

Similar to animals in nutrient needs and cellularstructure

Live freely in water; some live in animal hosts

Asexual (most) and sexual reproduction

Most are capable of locomotion by

Pseudopodia Cilia

Flagella



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Figure 1.6 Locomotive structures of protozoa-overview


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Algae

Unicellular or multicellular

Photosynthetic

Simple reproductive structures Categorized on the basis of pigmentation,

storage products, and composition of cell wall


Fi 1 7 Al i


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Figure 1.7 Algae-overview

Fi 1 8 A i t t f iti i bl d


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Figure 1.8 An immature stage of a parasitic worm in blood

Red blood cell

Fi 1 9 Vi i f ti b t i


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Figure 1.9 Viruses infecting a bacterium

Virus

Bacterium

Viruses

assemblinginside cell


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The Golden Age of Microbiology

Scientists searched for answers to four

questions

Is spontaneous generation of microbial life

possible? What causes fermentation?

What causes disease?

How can we prevent infection and disease?



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Some thought living things arose from

three processes

Asexual reproduction

Sexual reproduction Nonliving matter

Aristotle proposed

spontaneous generation(384-322 B.C.)

Living things can arise from nonliving matter



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Redis Experiments

When decaying meat was kept isolated from

flies, maggots never developed

Meat exposed to flies was soon infested

As a result, scientists began to doubt

Aristotles theory


Figure 1 10 Redis experiments: late 1600s


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Figure 1.10 Redi s experiments: late 1600s

Flask unsealed Flask sealed Flask coveredwith gauze


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Needhams Experiments

Scientists thought microbes, but not animals,

could arise spontaneously

Needhams experiments reinforced this idea



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Spallanzanis Experiments

Conclusions

Needham failed to heat vials sufficiently to kill all

microbes or had not sealed vials tightly enough Microorganisms exist in air and can contaminate

experiments

Spontaneous generation does not occur

Critics argued against experiments Sealed vials did not allow enough air for

organisms to survive

Prolonged heating destroyed life force


Figure 1 11 Louis Pasteur


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Figure 1.11 Louis Pasteur


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Pasteur Video

http://www.youtube.com/watch?v=0OmWbRK

W4K8

Th G ld A f Mi bi l
http://www.youtube.com/watch?v=0OmWbRKW4K8http://www.youtube.com/watch?v=0OmWbRKW4K8http://www.youtube.com/watch?v=0OmWbRKW4K8http://www.youtube.com/watch?v=0OmWbRKW4K8


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Pasteurs Experiments

When the swan-necked flasks remained

upright, no microbial growth appeared

When the flask was tilted, dust from the bendin the neck seeped back into the flask and

made the infusion cloudy with microbes

within a day


Figure 1.12 Pasteurs experiments with swan-necked flasks


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Figure 1.12 Pasteur s experiments with swan necked flasks

Steam escapesfrom open endof flask.

Infusion

is heated.

Infusion sits;

no microbes appear.

Months

Air moves inand out of flask.

Infusion remains

sterile indefinitely.

Dust fromair settlesin bend.

Th G ld A f Mi bi l


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The Scientific Method

*IdentifyQuestion

Form Hypothesis

Collect data by performing experiment

*Interpret results If hypothesis is rejected

Peer Review

Publish Findings


Th G ld A f Mi bi l


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The Scientific Method: Pasteurs experiment

*IdentifyQuestion

Form Hypothesis

Collect data by performing experiment

*Interpret results


Figure 1.13 The scientific method


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g

Observations

Question

Hypothesis

Repeat

Experiment,includingcontrol groups

Modifiedhypothesis

Observations

Experimentaldata supporthypothesis

Experimentaldata do notsupporthypothesis

Accepthypothesis

Rejecthypothesis

Modifyhypothesis

Theoryor law

Th G ld A f Mi bi l


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What Causes Fermentation?

Spoiled wine threatened livelihood of vintners

Some believed air caused fermentation

Others insisted living organisms causedfermentation

Vintners funded research to prevent spoilageduring fermentation

This debate also linked to debate overspontaneous generation


Figure 1.14 Pasteur's application of the scientific method


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Observation:

Hypothesis Experiment Observation Conclusion

Fermentinggrape juice

Microscopic analysisshows juice contains

yeasts and bacteria.

Day 1: Flasks of grape

juice are heated sufficiently

to kill all microbes.

Day 2

I. Spontaneous

fermentation

occurs.

II. Air ferments

grape juice.

III. Bacteria ferment

grape juice

into alcohol.

IV. Yeasts ferment

grape juice

into alcohol.

Juice in flask is

inoculated with

yeast and sealed.

Juice in flask is

inoculated with

bacteria and sealed.

Flask remainsopen to air

via curved neck.

Flask issealed.

No fermentation;

juice remainsfree of microbes

No fermentation;

juice remains

free of microbes

Bacteria reproduce;

acids are produced.

Yeasts reproduce;

alcohol is produced.

Reject

hypothesis I.

Reject

hypothesis II.

Modify hypothesis

III; bacteria ferment

grape juice into

acids.

Accept hypothesis

IV; yeasts ferment

grape juice into

alcohol.

Table 1.1 Some Industrial Uses of Microbes


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What Causes Disease?

Pasteur developed germ theory of disease

Robert Koch studied causative agents of

diseaseAnthrax

Examined colonies of microorganisms


Figure 1.15 Robert Koch


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Kochs Contributions

Simple staining techniques

First photomicrograph of bacteria

First photomicrograph of bacteria in diseasedtissue

Techniques for estimating CFU/ml

Use of steam to sterilize media

Use of Petri dishes Techniques to transfer bacteria

Bacteria as distinct species


Figure 1.16 Bacterial colonies on agar


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Bacterium 1

Bacterium 2

Bacterium 3

Bacterium 4

Bacterium 5

Bacterium 6 Bacterium 7

Bacterium 8

Bacterium 9

Bacterium 10

Bacterium 11

Bacterium 12



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Kochs Postulates Suspected causative agent must be found in

every case of the disease and be absent fromhealthy hosts

Agent must be isolated and grown outsidethe host

When agent is introduced into a healthy,susceptible host, the host must get the disease

Same agent must be found in the diseasedexperimental host


Table 1.2 Other Notable Scientists of the Golden Age of Microbiology and the Agents of Disease They Discovered


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Grams Stain Danish scientist Hans Christian Gram developed

more important staining technique than Kochsin 1884

Involves the applications of a series of dyes

Some microbes are left purple, now labeledGram-positive

Other microbes are left pink, now labeled Gram-

negative Gram procedure used to separate into two

groups


Figure 1.17 Results of Gram staining

G iti G ti


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Gram-positive Gram-negative



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How Can We Prevent Infection andDisease?

Semmelweisand handwashing

Listersantiseptic technique Nightingaleand nursing

Snowinfection control and epidemiology

Jennersvaccinefield of immunology

Ehrlichs magic bulletsfield ofchemotherapy



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Semmelweis and Lister video

http://www.youtube.com/watch?v=T73PYNyyeiI&feature=related

Figure 1.18 Florence Nightingale
http://www.youtube.com/watch?v=T73PYNyyeiI&feature=relatedhttp://www.youtube.com/watch?v=T73PYNyyeiI&feature=relatedhttp://www.youtube.com/watch?v=T73PYNyyeiI&feature=relatedhttp://www.youtube.com/watch?v=T73PYNyyeiI&feature=related


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Figure 1.19 Some scientific disciplines and applicationsBIOLOGISTS MODERN DISCIPLINES


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BIOLOGISTS MODERN DISCIPLINES

Pre-1857

The Golden Age ofMicrobiology (18571907)

Leeuwenhoek

Linnaeus

Semmelweiss

Snow

Bacteriology (bacteria)

Protozoology (protozoa)

Mycology (fungi)

Parasitology (protozoa and

animals)

Phycology (algae)

Taxonomy

Infection control

Epidemiology

Pasteur

Pasteurization

Industrial microbiology

Food and beverage technology

Buchner

Koch Kochs postulates

Ivanowski

Beijerinck

Winogradsky

Gram

Lister

Nightingale

Jenner

von Behring

Kitasato

Ehrlich

Fleming

Microbial metabolism

GeneticsGenetic engineering

Etiology

Virology

Environmental microbiology

Ecological microbiology

Microbial morphology

Antiseptic medical techniques

Hospital microbiology

Serology

Immunology

Chemotherapy

Pharmaceutical microbiology

Table 1.3 Fields of Microbiology


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The Modern Age of Microbiology


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What Are the Basic Chemical Reactions of Life?

Biochemistry

Began with Pasteurs and Buchners works

Microbes used as model systems for biochemicalreactions

Practical applications

Design of herbicides and pesticides

Diagnosis of illness and monitoring responses totreatment

Treatment of metabolic diseases

Drug design




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How Do Genes Work?

Microbial genetics

Molecular biology

Recombinant DNA technology Gene therapy




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Microbial Genetics

Avery, MacLeod, and McCarty: genes are

contained in molecules of DNA

Beadle and Tatum: a genes activity is related toprotein function

Translation of genetic information into protein

explained

Rates and mechanisms of genetic mutationinvestigated

Control of genetic expression by cells described




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Molecular Biology

Explanation of cell function at the molecular level

Pauling proposed that gene sequences could

Provide understanding of evolutionaryrelationships/processes

Establish taxonomic categories

Identify microbes that have never been cultured

Woese determined cells belong to bacteria,archaea, or eukaryotes

Cat scratch disease caused by unculturable

organism




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Recombinant DNA Technology

Genes in microbes, plants, and animals

manipulated for practical applications

Production of human blood-clotting factor byE. colito aid hemophiliacs

Gene Therapy

Inserting a missing gene or repairing a defectiveone in humans by inserting desired gene into

host cells




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What Roles Do Microorganisms Play in theEnvironment?

Bioremediation uses living bacteria, fungi,

and algae to detoxify polluted environments

Recycling of chemicals such as carbon,

nitrogen, and sulfur




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How Do We Defend Against Disease? Serology

The study of blood serum

Blood contains chemicals and cells that fight

infection

Immunology

The study of the bodys defense against specificpathogens

Chemotherapy Fleming discovered penicillin

Domagk discovered sulfa drugs


Figure 1.20 Effects of penicillin on a bacterial lawn in a petri dish


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Fungus colony(Penici l l ium)

Zone of inhibition

Bacterial colonies(Staphy lococcus )



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What Will the Future Hold?

Microbiology is built on asking and answering

questions

The more questions we answer, the morequestions we have

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