Lecture 1 - Introduction to Microbiology

8/13/2019 Lecture 1 - Introduction to Microbiology

1/21

Introduction to Microbiology

Dr. Linroy Christian


2/21

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


3/21

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


4/21

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


5/21

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


6/21

The History of Microbiology


7/21

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)


8/21

Van Leeuwenhoeks microscope


9/21

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


10/21

Pasteurs Experiment


11/21

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


12/21

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


13/21

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


14/21

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


15/21

Bacterial Colonies on Agar Plate


16/21

Culture Media


17/21

Developments in the 20th Century


18/21

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


19/21

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


20/21

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)


21/21

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

Lecture 1 - Introduction to Microbiology

Documents