Microbiology power point presentation

7/27/2019 Microbiology power point presentation

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Copyright 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings

Lecture prepared by Mindy Miller-Kittrell, University of Tennessee, Knoxville

M I C R O B I O L O G YWITH DISEASES BY BODY SYSTEM SECOND EDITIONChapter 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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How Can Microbes Be Classified?

Carolus Linnaeus (Swedish) developed taxonomic system fornaming plants and animals and grouping similar organismstogether

Leeuwenhoeks microorganisms grouped into six categories asfollows:

Fungi

Protozoa

Algae

Bacteria

Archaea

Small animals


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Fungi

Eukaryotic (have membrane-bound nucleus)

Obtain food from other organisms

Possess cell walls

Composed ofMolds multicellular; have hyphae; reproduce by sexual and

asexual spores

Yeasts unicellular; reproduce asexually by budding; some

produce sexual spores




Protozoa

Single-celled eukaryotes

Similar to animals in nutrient needs and cellular structure

Live freely in water; some live in animal hosts

Asexual (most) and sexual reproduction

Most are capable of locomotion byPseudopodia cell extensions that flow in direction of travel

Cilia numerous, short, hairlike protrusions that propelorganisms through environment

Flagella extensions of a cell that are fewer, longer, andmore whiplike than cilia




Algae

Unicellular or multicellular

Photosynthetic

Simple reproductive structures

Categorized on the basis of pigmentation, storage products, and

composition of cell wall




Bacteria and Archaea

Unicellular and lack nuclei

Much smaller than eukaryotes

Found everywhere there is sufficient moisture; some found inextreme environments

Reproduce asexually

Two kinds

Bacteria cell walls contain peptidoglycan; some lack cellwalls; most do not cause disease and some are beneficial

Archaea cell walls composed of polymers other thanpeptidoglycan



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 philosophers and scientists of the past thought living things arose

from three processes: asexual reproduction, sexual reproduction, or

from nonliving matter

Aristotle proposed spontaneous generation 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


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Needhams Experiments

Scientists did not believe animals could arise spontaneously, but

did believe microbes could

Needhams experiments with beef gravy and infusions of plantmaterial reinforced this idea


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Spallanzanis Experiments

Concluded that

Needham failed to heat vials sufficiently to kill all microbes orhad not sealed vials tightly enough

Microorganisms exist in air and can contaminate experiments

Spontaneous generation of microorganisms does not occur

Critics said sealed vials did not allow enough air for organisms tosurvive and that prolonged heating destroyed life force


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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 bend in the neck seepedback into the flask and made the infusion cloudy with microbes

within a day

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The Scientific Method

Debate over spontaneous generation led in part to development

of scientific method

A group of observations leads scientist to ask question about

some phenomenon

The scientist generates hypothesis (potential answer to

question)

The scientist designs and conducts experiment to test

hypothesisBased on observed results of experiment, scientist either

accepts, rejects, or modifies hypothesis

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What Causes Fermentation?

Spoiled wine threatened livelihood of vintners, compelling themto fund research into how to promote production of alcohol butprevent spoilage by acid during fermentation

Some believed air caused fermentation reactions, while others

insisted living organisms caused fermentation This debate also linked to debate over spontaneous generation

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The Golden Age of Microbiolog


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What Causes Disease?

Pasteur developed germ theory of disease Robert Koch studied causative agents of disease

Anthrax

Examined colonies of microorganisms


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Kochs Experiments

Simple staining techniques

First photomicrograph of bacteria

First photomicrograph of bacteria in diseased tissue

Techniques for estimating CFU/ml

Use of steam to sterilize media

Use of Petri dishes

Aseptic techniques

Bacteria as distinct species



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Kochs Postulates

Suspected causative agent must be found in every case of thedisease and be absent from healthy hosts

Agent must be isolated and grown outside the host

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

Same agent must be reisolated from now-diseased experimentalhost



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How Can We Prevent Infection and Disease?

Semmelweis and handwashing

Listers antiseptic technique

Nightingale and nursing

Snow infection control and epidemiology

Jenners vaccine field of immunology

Ehrlichs magic bullets field of chemotherapy



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The Modern Age of Microbiology


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What Are the Basic Chemical Reactions of Life?

BiochemistryBegan with Pasteurs work on fermentation and Buchners

discovery of enzymes in yeast extract

Kluyver and van Niel microbes used as model systems forbiochemical reactions

Practical applications

Design of herbicides and pesticides

Diagnosis of illnesses and monitoring of patientsresponses to treatment

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 determined genes are contained

in molecules of DNA

Beadle and Tatum established that a genes activity is related to

protein function

Translation of genetic information into protein explained

Rates and mechanisms of genetic mutation investigated

Control of genetic expression by cells described



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Molecular Biology

Explanation of cell function at the molecular level

Genome sequencing

Pauling proposed that gene sequences could

Provide understanding of evolutionary relationships and

processesEstablish taxonomic categories that reflect these

relationships

Identify existence of microbes that have never been cultured

Woese determined that cells belong to bacteria, archaea, oreukaryotes

Cat-scratch fever caused by unculturable organism



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Recombinant DNA Technology

Genes in microbes, plants, and animals manipulated for practicalapplications

Production of human blood-clotting factor by E. colito aidhemophiliacs

Gene Therapy

Inserting a missing gene or repairing a defective one in humansby inserting desired gene into host cells



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What Role Do Microorganisms Play in the Environment?

Bioremediation uses living bacteria, fungi, and algae to detoxifypolluted environments

Recycling of chemicals such as carbon, nitrogen, and sulfur



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How Do We Defend Against Disease?

SerologyThe study of blood serum

Von Behring and Kitasato existence in the blood of

chemicals and cells that fight infection

Immunology

The study of the bodys defense against specific pathogens

Chemotherapy

Fleming discovered penicillinDomagk discovered sulfa drugs



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What Will the Future Hold?

Microbiology is built on asking and answering questions

The more questions we answer, the more questions we have

Documents

Microbiology power point presentation