Introduction to Microbiology

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Feb 20, 2013 (4 years and 5 months ago)

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Introduction to
Microbiology

Dr Paul Brown

paul.brown@uwimona.edu.jm

BC10M: Introductory Biochemistry

Lecture 1

Teaching Objectives

To give an overview of the history of
Microbiology


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

Learning Outcomes…I

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


The important developments in Microbiology


Describe basic and specialised microscopy
techniques and their applications


The extent of the microbial world


Describe the important differences between
prokaryotes (Bacteria and Archaea) and
eukaryotes

Learning Outcomes…II

At the end of this section, students should
be able to:


Describe basic and specialized techniques for
quantifying microbial growth


Summarize the process of bacterial and viral
reproduction and describe the dynamics of a
bacterial growth curve and the plaque assay


Indicate how bacteria are divided into groups
according to their phylogeny &/or metabolism

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 assay

Microbial diversity


Phylogeny


Substrate utilization

References

Madigan et al.
Brock’s Biology of
Microorganisms

: 9
th
, 10
th

eds.

Prescott et al.,
Microbiology,

3
rd
, 4
th

eds.

Black,
Microbiology
, 4
th

ed.

Other Microbiology texts

Introduction

“microbiology’
-

the study of
microorganisms

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 incompletely
sterilised food cans


e.g., disease in animals and plants


Microbial World

Viruses

Bacteria (Eubacteria) and
Archaeabacteria

Fungi (Yeasts and Molds)

Protozoa

Microscopic Algae

Benefits

Maintain balance of environment
(microbial ecology)

Basis of food chain

Nitrogen fixation

Photosynthesis

Digestion, synthesis of vitamins

Manufacture of food and drink


Benefits

Genetic engineering

Synthesis of chemical products

Recycling sewage

Bioremediation: use microbes to
remove toxins (oil spills)

Use of microbes to control crop pests

Normal microbiota

Harmful Effects

Cause disease (basis for bioterrorism)



Food spoilage

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)


Redi’s experiments first to dispprove S.G.

Pioneers of Microbiology

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 all
the basic functions of living things

Pasteur, FR and Tyndall, UK (1861)


Finally disproved S.G.

Pioneers of Microbiology

Louis Pasteur (1822
-
1895), Chemist


Fermentation (1857)


Pasteurization: heat liquid enough to kill
spoilage bacteria (1864)


Vaccine development


rabies


Proposed the germ theory of disease


Proposed aseptic techniques (prevent
contamination by unwanted microbes)


Director of Pasteur Institute, Paris (1894)

Pioneers of Microbiology

Joseph Lister, UK (1867)


Used phenol (carbolic acid) to disinfect
wounds


First aseptic technique in surgery

Robert Koch, DE (1876)


Postulates


Germ theory

(1876)


Identified microbes that caused anthrax
(1876),
tuberculosis

(1882) and
cholera

(1883)


Developed microbiological media & streak
plates for
pure culture

(1881)

Koch’s Postulates

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

The disease organism must be isolated from the
lesions of the infected case and maintained in pure
culture.

The pure culture, inoculated into a susceptible or
experimental animal, should produce the symptoms
of the disease.

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

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)

Branches of Microbiology

Parasitology: study of protozoa and parasitic
worms

Chemotherapy


Treatment of disease by using chemical means


Antibiotics produced naturally


Synthetic drugs


Paul Ehrlich

(1878)


used arsenic compounds to
fight disease


‘magic bullet’

Branches of Microbiology

Chemotherapy


Alexander Fleming, Scotland (1928) discovered
penicillin


Selman Waksman, Ukraine (1944) discovered
streptomycin

Problems


Toxicity of drugs => Selective toxicity


Resistance of bacteria to drugs

Branches of Microbiology

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


Branches of Microbiology

Biotechnology


GMOs/GEMs for industrial, pharmaceutical and
agricultural applications


Improvements of agriculture (plants and
animals)


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