lecture 1 - introduction to microbiology
TRANSCRIPT
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Introduction to Microbiology
Dr. Linroy Christian
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Definition of Microbiology
The study of microorganisms
Organisms too small to be seen by the naked eye
Objects < 0.1 mm cannot be perceived by the human
eye
Bacteria, fungi, viruses, algae, protozoa Characteristics of microorganisms
Unicellular
Free of organelles
Generally prokaryotic, but some are eukaryotic
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Aspects of Microbiology- What
Microbiology is all about?
It is about:
living cells and how they work Free-living microorganisms and their importance, in
particular the bacteria
Microbial diversity and evolution and how different
kinds of microbes arose and why
How microbes impact on human society, in ourbodies and in animals and plants
The central role of microbes in basic biologicalscience leading to an understanding of higherorganisms
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Why Study Microbiology? Two major reasons
(1) As a basic biological science, microbiology providesaccess to research tools for probing the nature of lifeprocesses. A general understanding of chemical andphysical principles has arisen from the study of
microorganisms (2) As an applied science, microbiology deals with many
important practical problems in medicine, agriculture andindustry:
Human, animal and plant diseases Soil fertility
Human life and industry
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Impact of Microorganisms on
Human Affairs Disease
Agriculture
Nitrogen fixation Rumen digestion
Cycling of nutrients
disease
Food industry Cheese, yogurt, sauerkraut, pickles, baked goods, alcoholic beverages
Energy Methane production, crude oil degradation, alternative sources of
energy
Chemotherapy Production of antibiotics
Biotechnology Genetic engineering, insulin production in Escherichia coli
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The History of Microbiology
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Antoni van Leeuwenhoek Dutch amateur microscope maker in the 17th century
Invented the simple microscope and was first to describe
microorganisms in detail He did not invent the microscope, the compound
microscope was developed in the late 16th century Robert Hooke 1664 described fruiting bodies of fungi
The father of animal histology and microbiology Discovered existence of spermatozoa and red blood cells Published paper in 1684 describing wee Animalcules
Advances in microbiology were made in the late 19th
century due to: Advancement in microscopy
Advancement in techniques for the visualisation anddifferentiation of microorganisms (gram stain in 1884)
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Van Leeuwenhoeks microscope
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Spontaneous Generation Life arising from something non-living
Most powerful opponent of this theory, FrenchChemist Louis Pasteur
Pasteurs Experiments Showed structures in air resembled microbes seen in
spoiled food Used heat to sterilize spoiled material and showedthat air introduced contaminants that causedputrefaction, thus refuting the claims of spontaneousgeneration
The principles of sterilization and aseptictechniques were born. Such techniques arecrucial to microbiology and in human industry
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Pasteurs Experiment
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Major drawback of Pasteurs
Experiments
Endospores
Heat resistance
Work of Ferdinand Cohn and Robert Koch
discovered endospores in Bacillus
If heat was not applied then viruses would
have been a potential issue
Heat sterilisation in brief
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Germ Theory of Disease Robert Koch and the study of Anthrax and its etiology
He found that large amounts of bacteria were found in
the blood of sick animals Animal experiments
Blood transfer
Inoculation with pure bacterial culture
The experiments gave rise to Kochs Postulate whichdemonstrated the role of microorganisms in disease andspurred the development of microbiology, stressing theimportance of laboratory culture
The essential general conclusion to be drawn from thiswork is that specific microorganisms have specificeffects
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Kochs Postulate (1) The organisms should be constantly present
in the animal suffering from the disease andshould be absent in health animals
(2) The organisms must be cultivated in pureculture
(3) The pure culture should producecharacteristics of the disease when injected intoa susceptible animal
(4) The organisms should be re-isolated fromthe infected animal and cultured in thelaboratory. The laboratory culture should be thesame as the original organism
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Pure Cultures
Kochs contribution
The use of solid media such as potatoes
The bacterial colony
Streaking technique
The birth of the solid culture medium
gelatin
The use of agar media today and the
development of microbial culture techniques
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Bacterial Colonies on Agar Plate
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Culture Media
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Developments in the 20th Century
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The Development of Applied
Microbiology Medical Microbiology and Immunology
Based on the work of Koch and others, many new pathogens
discovered The bodys defense to pathogens understood
Agricultural Microbiology and the understanding of soilbiology
Soil microorganisms and the formation of antibiotics The birth of antibiotics and chemotherapy (Alexander Fleming
and the discovery of penicillin in 1929)
Industrial Microbiology Fermentation
Large-scale production of chemicals
Aquatic Microbiology Microbial processes in water bodies such as lakes, streams and
the ocean
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The Development of Applied
Microbiology
Sanitary Microbiology
Sewage treatment plants and anaerobic digestion
Drinking Water Microbiology
Study and elimination of microbes from drinking water
However, all of these sub-disciplines can becategorised as microbial ecology
Developments in applied microbiology have led
to advancements in human society
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The Development of Basic
Microbiology Advancements in basic microbiology have provided support for
advancements in applied microbiology
Taxonomy- The science of classification Bacterial Physiology The nutrients bacteria consume and products theymake
Cytology
Bacterial Biochemistry
Bacterial Genetics
Molecular Biology DNA, RNA and protein synthesis
Molecular sequencing
Revolution of bacterial classification
Human genome project
Virology Biotechnology
Genetic engineering
Genetically Modified Organisms (GMOs)
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Summary
The influence of microorganisms on
human society is clear
Pasteur stated The role of the infinitely
small is infinitely large
The early work of many scientists
contributed to the development of the field
of microbiology and consequently thequality of life we have today