introduction microb

7/28/2019 Introduction Microb

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Introduction toMicrobiologyDr Paul Brown

[email protected]

BC10M: Introductory Biochemistry

Lecture 1


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Teaching Objectives

To give an overview of the history ofMicrobiology

To introduce the following:

The extent of the microbial world

Microscopy theory

Fundamental and quantitative techniques

Bacterial and viral growth characteristics

Microbial phylogenetic and metabolic diversity


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Learning OutcomesI

At the end of this section, students willhave an appreciation of &/or be able to:

The important developments in Microbiology

Describe basic and specialised microscopytechniques and their applications

The extent of the microbial world

Describe the important differences betweenprokaryotes (Bacteria and Archaea) and

eukaryotes


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Learning OutcomesII

At the end of this section, students shouldbe able to:

Describe basic and specialized techniques forquantifying microbial growth

Summarize the process of bacterial and viralreproduction and describe the dynamics of abacterial growth curve and the plaque assay

Indicate how bacteria are divided into groups

according to their phylogeny &/or metabolism


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Lecture Plan

Scope of Microbiology Extent of the microbial world

History of Microbiology

Techniques

Microscopy and Staining Pure culture methods

Quantitative methods

Microbial growth curve

Plaque assayMicrobial diversity Phylogeny

Substrate utilization


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References

Madigan et al. Brocks Biology ofMicroorganisms : 9th, 10th eds.

Prescott et al., Microbiology, 3rd

, 4th

eds.

Black, Microbiology, 4th ed.

Other Microbiology texts


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Introduction

microbiology- the study ofmicroorganisms

organisms to small to be seen with the

naked eye except in large groups

effects of large numbers often visible e.g., chemical reactions in soil horizons

e.g., toxin and gas production in incompletelysterilised food cans

e.g., disease in animals and plants


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Microbial World

Viruses

Bacteria (Eubacteria) andArchaeabacteria

Fungi (Yeasts and Molds)

Protozoa

Microscopic Algae


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Benefits

Maintain balance of environment(microbial ecology)

Basis of food chain

Nitrogen fixation

Photosynthesis

Digestion, synthesis of vitamins

Manufacture of food and drink


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Benefits

Genetic engineering

Synthesis of chemical products

Recycling sewage

Bioremediation: use microbes toremove toxins (oil spills)

Use of microbes to control crop pests

Normal microbiota


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Harmful Effects

Cause disease (basis for bioterrorism)

Food spoilage


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Pioneers of Microbiology

Robert Hooke, UK (1665)

Proposed the Cell Theory

Observed cork with crude microscope

All living things are composed of cells

Spontaneous generation

Some forms of life could arise

spontaneously from non-living matter

Francesco Redi, IT (1668)

Redis experiments first to dispprove S.G.


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Antoni van Leeuwenhoek, DE (1673) First observed live microorganisms

(animalcules)

Schleiden and Schwann, DE Formulated Cell Theory: cells are the

fundamental units of life and carry out allthe basic functions of living things

Pasteur, FR and Tyndall, UK (1861) Finally disproved S.G.


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Louis Pasteur (1822-1895), Chemist Fermentation (1857)

Pasteurization: heat liquid enough to killspoilage bacteria (1864)

Vaccine development rabies

Proposed the germ theory of disease

Proposed aseptic techniques (preventcontamination by unwanted microbes)

Director of Pasteur Institute, Paris (1894)


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Joseph Lister, UK (1867) Used phenol (carbolic acid) to disinfect

wounds

First aseptic technique in surgeryRobert Koch, DE (1876) Postulates Germ theory (1876)

Identified microbes that caused anthrax

(1876), tuberculosis (1882) and cholera(1883)

Developed microbiological media & streakplates for pure culture (1881)


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Kochs Postulates

The specific causative agent must be found in everycase of the disease.

The disease organism must be isolated from thelesions of the infected case and maintained in pure

culture.

The pure culture, inoculated into a susceptible orexperimental animal, should produce the symptomsof the disease.

The same bacterium should be re-isolated in pureculture from the intentionally infected animal.


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Branches of Microbiology

Bacteriology: study of bacteria

Mycology: study of fungi

Immunology: study of immunity Edward Jenner, UK: developed vaccination

(1798)

Metchnikoff, RU: discovered phagocytes (1884)

Paul Ehrlich, DE: theory of immunity (1890)

Virology: study of viruses Beijerinck, NE: discovered intracellular

reproduction of TMV; coined the term virus(1899)


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Parasitology: study of protozoa and parasiticworms

Chemotherapy

Treatment of disease by using chemical means

Antibiotics produced naturally

Synthetic drugs

Paul Ehrlich (1878) used arsenic compounds to

fight disease magic bullet


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Chemotherapy

Alexander Fleming, Scotland (1928) discovered

penicillin Selman Waksman, Ukraine (1944) discovered

streptomycin

Problems

Toxicity of drugs => Selective toxicity Resistance of bacteria to drugs


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Recombinant DNA Technology Recombinant DNA

Genetic engineering/biotechnology Microbial genetics mechanism by which

microbes inherit genes

Molecular biology structure and

function (expression) of genes Molecular epidemiology/diagnostics


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Biotechnology

GMOs/GEMs for industrial, pharmaceutical and

agricultural applications Improvements of agriculture (plants and

animals)

Gene therapy: inserting a missing gene orreplacing a defective one in human cells

introduction microb

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