1. General Microbiology
Microbiolgy (Mikros, “small”, Bioc,
“life”, logia, “study of microscopic
organisms.
Microorganisms can be too small to
be seen by the naked eye such as
bacteria, viruses, etc….Or big
enough such as the bread mold,
some algae, etc..
Microbiology encompasses
numerous sub-disciplines including
virology, mycology, parasitology, and
bacteriology.
Bacteria
Virus
2. The Science of Microbiology
Microbiology revolves around two themes:
1. Understanding basic life processes
Microbes are excellent models for
understanding cellular processes in
unicellular and multicellular organisms
2. Applying that knowledge to the benefit of
humans
Microbes play important roles in
medicine, agriculture, and industry
3. Classification of organisms
Classification of organisms into five kingdoms
Monera Protista Fungi Animalia Plantae
Prokaryotes Eukaryotes
Human Plant
4. Classification of organisms
Microbiologist believe that organisms should be
divided among three domains
Bacteria
prokaryotic or single cell
Archaea
Prokaryotic but
different from
bacteria
Eucarya
Larger than
prokaryote, algae,
slime mold
Viruses are not classified in any kingdom
They are 10.000x smaller than bacteria
Invade host cell in order to replicate
5. History of Microbiology
Humans realized that
microbes were linked to
disease long time ago
and used them as
weapons to poison the
wells of the enemy
(throwing dead bodies
in the water).
Also, people who
suffered from infectious
disease were kept in
isolation even though
the process of infection
was not entirely
understood (bad air?)
Egyptian papyrus
6. Microscopy
Any thing less than one millimeter
must be examined via microscope
Several scientist contributed to the
discovery of microscopes,
Johannes Janssen (1590), Galileo
Galilei (1609) and Robert Hooke
(1660)
They all contributed in one way or
another to development of
microscopes
7. He is "the Father of Microbiology", and
considered to be the first microbiologist
Leeuwenhoek made more than 500 optical
lenses.
He also created at least 25 microscopes, of
differing types, of which only nine survived
he was the first to observe and describe
single-celled organisms, which he originally
referred to as animalcules
Antony Van Leeuwenhoek (1632)
8. He was the first to publish extensive and
accurate observations of microorganisms
In 1673, he sent a detailed letter to the royal
society of London describing bacteria
His work really advanced the microbiology
field
However the big advance in the microbiology
field was not seen until bacterial culturing
starts
Antony Van Leeuwenhoek (1632)
9. Antony Van Leeuwenhoek (1632)
The Antony Van Leeuwenhoek
microscope
Antony Van Leeuwenhoek
drawings of bacteria
10. Robert Hooke (1665)
•The English father of microscopy
•Re-confirmed Antony van Leeuwenhoek's
discoveries of the existence of tiny living
organisms
•He made a copy of Leeunwenhoek's
microscope and improved upon his design
•He wrote Micrographia, the first book
describing observations made through a
microscope.
flea and louse drawing
obtained from micrographia
11. Robert Hooke and early microscopy
The Robert Hooke
microscope
Fruiting bodies of mold, round
structures contain spores of
the mold as published in the
micrographia
12. Louis Pasteur (1822–1895)
•Discovered that alcoholic fermentation
was a biologically mediated process
(originally thought to be purely chemical)
•Developed vaccines for anthrax,
cholera, and rabies
•Led to the development of methods for
controlling the growth of microorganisms
(aseptic technique)
16. Robert Koch (1843–1910)
– Demonstrated ()اظهر the link between
microbes and infectious diseases
Identified causative agents of anthrax and
tuberculosis
– Developed techniques (solid media) for
obtaining pure cultures of microbes, some
still in existence today
– Awarded Nobel Prize for Physiology and
Medicine in 1905
– Koch’s postulates
18. Koch’s postulates for proving cause and
effect in infectious diseases.
Sick mouse Spleen of sick
mouse
Grew on bacterial
plates until getting
pure culture
Inject healthy mouse with
suspected bacteria
Sick…
Isolate the same bacteria
from the second mouse
19. Koch, Infectious Disease, and Pure
Culture Microbiology
Koch’s Postulates Today
– Koch’s postulates apply for diseases that have an
appropriate animal model
– Animal models not always available
For example, cholera, rickettsias, chlamydias
– Remain “gold standard” in medical microbiology, but not
always possible to satisfy all postulates for every infectious
disease
Koch and the Rise of Pure Cultures
– Discovered that using solid media provided a simple way of
obtaining pure cultures
– Began with potato slices, but eventually devised uniform
and reproducible nutrient solutions solidified with gelatin
and agar
20. Other contributors
Edward Jenner (1796)
vaccinates people to
protect them from smallpox
Ferdinand Cohn (1828–
1898): founded the field of
bacterial classification and
discovered bacterial
endospores This young girl in
Bangladesh was
infected with
smallpox in 1973
caused by virola
virus
Bacillus subtilis
endospore
stained in blue
21. Major contributors in microbiology
Giants of the early days of microbiology
and their major contributions
22. General Microbiology fields
Basic microbiology
cytology, genetics,
physiology
Medical microbiology
agriculture Microbiology
Industrial Microbiology
Public health
microbiology
Applied microbiology
23. Microbes = disease?
When we think of microbial organisms we
immediately think of disease, but in fact the great
majority of microorganisms are beneficial to us and
the planet.
Of all known species of bacteria 87% are beneficial
10% are opportunistic pathogens (cause
diseases only under certain conditions)
Only 3% are true pathogens
24. Microbes and human health
Normal microbiota: from the moment we are
born we live with a great number of
microorganisms that grow and divide on or
inside our body. These microorganisms can
be extremely beneficial to us (e.g. bacteria
that synthesize vitamin K and B in our gut) .
Pathogenic: microorganisms cause infectious
diseases (that can be transmitted from
person to person). We know bacterial (e.g.
cholera), viral (e.g. AIDS, flu), and protozoan
(e.g. malaria) diseases.
25. Death rates for the leading causes of
death in the United States: 1900 & today
26. The Impact of Microorganisms on
Humans
Microorganisms and Agriculture
– Many aspects of agriculture depend on microbial
activities
• Positive impacts
– nitrogen-fixing bacteria
– cellulose-degrading microbes in the rumen
– Insect pest control by microorganisms: Bacillus
thuringiensis.
– Recycling of vital elements: C, N, O, S and P
converted by microorganisms into forms that
can be used by plants and animals
Negative impacts
– diseases in plants and animals
28. The Impact of Microorganisms on
Humans
Microorganisms and Food
– Negative impacts
Food spoilage by microorganisms requires
specialized preservation of many foods
– Positive impacts
Microbial transformations (typically
fermentations) yield
– dairy products (e.g., cheeses, yogurt,
buttermilk)
– other food products (e.g., pickles,
breads, beer)
29. The Impact of Microorganisms on
Humans
Microorganisms, Energy, and the
Environment The role of microbes in biofuels
production
For example, methane, ethanol, hydrogen
30. The Impact of Microorganisms on
Humans
The role of microbes in cleaning up
pollutants & toxic wastes
(bioremediation)
31. The Impact of Microorganisms on
Humans
Microorganisms and Their Genetic
Resources
– Exploitation of microbes for
production of antibiotics, enzymes,
and various chemicals
– Genetic engineering of microbes to
generate products of value to
humans, such as insulin
(biotechnology)
Editor's Notes
The fact that we can use microbiology to do genetic manipulations as it is easier to grow bacteria in culture
Microorganisms are diverse and their classification is difficult . For instance; some microorganisms are motile like animals but have features similar to plants So we can not put it in certain kingdom(not animal not plant kingdom
Microorganisms are diverse and their classification is difficult . For instance; some microorganisms are motile like animals but have features similar to plants So we can not put it in certain kingdom(not animal not plant kingdom
The Italian in the 13th century, the earliest simple forms of magnification were magnifying glasses, usually about 6x - 10x and were used for inspecting tiny insects such as fleas, hence these early magnifiers called "flea
Figure 1.12 Robert Hooke and early microscopy.
Several theories were generated by different scientist on where bacteria are coming from and how do they grow
Pasteur filtered air through filter paper and he found that objects were trapped on the filter paper
Then he put the filter paper into sterile medium and he found that the bacteria grew
Pasteur showed how to keep a solution sterile, he placed solutions in flasks , heated their necks and drew them into different curves
He boiled the flask and let to cool down
He noticed no growth because the bacteria were stuck on the walls of curved necks. However when he broke the neck he saw bacterial growth
Pasteur work opened a lot of ideas for other scientist and within 60 years a number of disease causing microbes number of techniques for isolating and culturing microbes were discovered
He tried to produce alcohol from sugar beets
Fermentation is a metabolic process converting sugar to acids, gases and/or alcohol using yeast or bacteria
Microbiology looks at microbes physiology (bacteriology, virology) and at their role in relation with humans. We will look at structure and function as well as microbial interactions with humans and the environment. So many aspects of bacterial life style such as antibiotics, how bacteria grow and get nutrients , study the bacterial cell, metabolism
Industrial cheese making and yogurt beers
Also how bacteria can spoil food
Normal flora
1- some bacteria synthesize and secrete vitamin K and B12 (mice exp)
2-some normal flora prevent the colonization of pathogenic bacteria, they compete for attaching site and nutrient (salmonella exp)
3- the normal flora may antagonize the effect of pathogenic bacteria
4- normal flora is involved in the development of tissues such as the pyeres patches in the intestine
Microorganisms also play important roles in the food industry, both harmful and beneficial. Because food fit for human consumption can support the growth of many microorganisms, it must be properly prepared and monitored to avoid transmission of disease.
Foods that benefit from the effects of microorganisms include cheese, yogurt, buttermilk, sauerkraut, pickles, sausages, baked goods, and alcoholic beverages.
Microorganisms are important in energy production, including the production of methane (natural gas), energy stored in organisms (biomass), and ethanol.
Biotechnology is the use of microorganisms in industrial biosynthesis, typically by microorganisms that have been genetically modified to synthesize products of high commercial value.
Various microorganisms can be used to consume spilled oil, solvents, pesticides, and other environmentally toxic pollutants.