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Microbiology

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Title: Microbiology


1
Microbiology
Chapter 1 The Microbial World and You
2
Microorganisms and Microbiology
  • Microbiology is the study of microorganisms
  • Microscopic, single cell, cluster, chains
  • carry out life processes independently as single
    cells
  • Viruses- microscopic, non-cellular, RNA or DNA
  • Bacteria and their processes and their effects on
    society, humans, animals and environment
  • Two basic themes
  • Basic- cellular processes
  • Applied practical problems in agriculture,
    health and industry
  • Importance of microorganisms
  • 1. evolution of oxygen and first cells on early
    Earth
  • 2. activities affect the entire web of life on
    Earth

3
MICROBES EXIST EVERYWHERE
4
Microorganisms and Their Environment
  • Microbes exist in populations that occupy a
    location in the environment (habitat)
  • Populations of cells rarely live alone and form
    assemblages of different populations (microbial
    communities)
  • Microbial communities free swimming or biofilms
    (attached to a surface)
  • Interactions between communities may be
  • 1. beneficial cooperative feeding efforts
  • (waste-nutrient)
  • 2. harmful - waste product is inhibitory
  • Ecosystem Living organisms together with
    physical and chemical constituents of environment

5
Extent of Microbial Life
  • Strength is in numbers 5 x 1030 for prokaryotes
    (bacteria)
  • Total carbon in this number of small cells equals
    that of all plants on Earth
  • Prokaryotic cells
  • 1. Constitute the major portion of biomass on
    Earth
  • 2. Key reservoirs of essential nutrients for
    life
  • Most of the prokaryotes are in oceanic and
    terrestrial subsurfaces

6
Microbes and Agriculture
  • Nitrogen fixation
  • 1. association between plants (legumes) and
    bacteria
  • 2. reduce need for fertilizer
  • Rumen microbes in cattle and sheep allow them to
    breakdown/digest grass and hay
  • Nutrient cycling (C, N, and S)
  • Plant and animal diseases

7
  • 1. Microorganisms and Food
  • prevent microbial spoilage of food and food borne
    disease
  • Manufacturing of foods
  • 2. Microorganisms, energy and environment
  • Natural gas (methane)
  • Ethanol (biofuel)
  • Bioremediation
  • 3. Microbes and the future
  • Biotechnology-genetic engineering

8
Microorganisms are especially useful in research
  • 1. Have relatively simple structures
  • 2. Large numbers of microbes can be used in an
    experiment to obtain statistically reliable
    results at a reasonable cost
  • 3. Reproduce quickly so they are useful for
    studies involving transfer of genetic information

9
The prefix "micro" means small, and most microbes
cannot be seen without a microscope. Eukaryotic
microbes are the biggest, generally ranging from
a few micrometers (µ) to many hundreds of µ.
Bacterial cells usually range from 0.5 µ to 5.0
µ (although some bacteria have been found that
are much larger.) Viruses are much smaller,
usually less than 0.1µ. Our eyes cannot resolve
objects smaller than 0.2mm (200µ.) However, if
you squint at a jar of fresh pond water, you can
often just make out some large protists such as
ciliated paramecia.
10
Naming organisms
  • Binomial nomenclature was created by Carolus
    (Karl) Linnaeus
  • 2 name naming (genus and species)
  • Use Latin
  • Genus is capitalized (Streptococcus)
  • Species is small case (aureus)
  • Always use italics or underline

11
The figure to the left shows the 3-Domain
classification of organisms. Bacteria and
Archaea consist of prokaryotic microbes, whereas
Eukarya consists of eukaryotic microbes as well
as plants and animals.
12
There are four major kinds of microbes
bacteria, fungi, protists, and viruses.
This microbe is a type of protist called a
ciliate.
Bacterial cells are prokaryotic, which means they
lack internal membrane bound organelles such as
nuclei and mitochondria. Fungi and protists are
eukaryotic they have a cell nucleus containing
multiple chromosomes, and other membrane bound
organelles. Viruses are not cells at all-- they
are tiny, inert particles containing DNA or RNA
that must infect an appropriate host cell in
order to reproduce and survive.
13
Bacteria (singular bacterium)
  • Single-celled organisms
  • Prokaryotes
  • Shapes
  • 1. Spherical
  • 2. Rod
  • 3. Spiral

14
Streptococcus sp.
Klebsiella pneumoniae (5,821X)
Treponema pallidum
15
Algae (singular alga)
  • Single-celled microorganisms
  • Eukaryotic
  • Nucleus and membrane-bound organelles
  • Photosynthetic
  • Fresh water and marine environments

16
Micrasteria (334X)
17
Fungi (singular fungus)
  • Single-celled microorganisms (Yeasts)
  • Multi-cellular microorganisms (Molds)
  • Eukaryotic
  • Widely distributed in water and soil as
    decomposers of dead organisms
  • Some are important in medicine

18
Philobolus crystallinus (50x)
19
Viruses
  • Acellular entities too small to be seen with a
    light microscope
  • Composed of nucleic acid and protein
  • Bacteriophage viruses that infect bacteria
  • Viroids nucleic acid without a protein coating
  • Prions Infectious proteinaeceous particles

20
Bacteriophages (35,500x)
21
Protozoa (singular protozoan)
  • Single-celled, microorganisms
  • Eukaryotic
  • Have a nucleus (membrane-bound) and other
    intracellular structures
  • Found in a variety of water and soil environments

22
Amoeba (183X)
23
Acanthrocirrus retrirostris (189X).
Helminthes multicellular animal parasites some
life stages are microscopic and pathogenic
24
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25
Why have people been so interested in figuring
out what causes disease? The Triumph of
Death by Pieter Breughel, the Elder
Yersinia pestis The black Death is bubonic
plague caused by a bacterium
26
History of microbiology
  • http//users.stlcc.edu/kkiser/History.page.html
    this site has a time line and pictures of the
    major players in early microbiology
  • Cell theory-Hookes discovery marked the
    beginning of this
  • Spontaneous generation-life from non-life
  • Much early micro work was to either prove or
    disprove this theory
  • Biogenesis-living cells come from pre-existing
    cells
  • Aseptic technique-germ free
  • Golden age of microbiology-began with Pasteurs
    work
  • Germ theory of disease-proved by Koch

27
Historical Scientists in Microbiology
  • 1. Antony van Leeuwenhoek
  • 2. Louis Pasteur
  • 3. Joseph Lister -antiseptic
  • 4. Edward Jenner - vaccination
  • 5. Elie Metchnikoff - immunology
  • 6. Paul Ehrlich chemotherapy- magic bullets
    - antibiotics
  • 7. Alexander Fleming discovered penicillin

28
Historical Roots of Microbiology
  • -1664 Robert Hooke - cellulae
  • -1684 A. V. Leeuwenhoek
  • -Ferdinand Cohn founder of bacteriology
  • - Louis Pasteur Disproved Spontaneous
    generation, vaccination, pasteurization
  • -Robert Koch germ theory, demonstrates that
    specific microorganisms cause specific disease
    (Kochs postulates)
  • Isolation of harmful pathogens
  • developed techniques that furthered
    advancement of Microbiology

29
Anton van Leeuwenhoek (1632-1723) See figure 1.2
page 7
30
Unifying Theories of Microbiology
  • The Cell Theory All cells are the fundamental
    units of life and carry out all basic functions
    of living things
  • The Germ Theory of Disease States that
    microorganisms can invade other organisms and
    cause disease

31
Disproof of Spontaneous Generation (Aristotelian
Abiogenesis)
  • 1. Francesco Redi flies in the jar
  • At the time, prevailing wisdom was that maggots
    formed naturally from rotting meat. In the
    experiment, Redi took eight jars, which he
    divided in two groups of four in the first jar
    of each group, he put an unknown object in the
    second, a dead fish in the last, raw chunk of
    veal. Redi took the first group of four jars, and
    covered the tops with fine gauze so that only air
    could get into it. He left the other group of
    jars open. After several days, he saw maggots
    appear on the objects in the open jars, on which
    flies had been able to land, but not in the
    gauze-covered jars.
  • 2. Lazaro Spallanzani boiling sterilization
  • Spallanzani researched the theory about the
    spontaneous generation of cellular life in 1768.
    His experiment proved that microbes come from the
    air and that they could be killed through
    boiling. This work paved the way for later
    research by Louis Pasteur.
  • 3. Louis Pasteur Swan necked flask experiment
  • 4. John Tyndall settling dust experiment in
    air-tight box
  • In the lab he developed 'optically pure' (i.e.
    extremely filtered) air. This air contained
    relatively very little or no micro-organisms. He
    compared what happened when he let prepared meat
    sit in such pure air and in ordinary air. The
    preparations in the pure air didn't go putrid,
    unlike the ones in ordinary air. These studies
    extended Louis Pasteur's recent demonstrations
    about germs.

32
A swan-necked flask that Pasteur used in
refuting the theory of spontaneous generation
33
Pasteurs Further Contributions
  1. Developed the technique of pasteurization to kill
    unwanted microorganisms
  2. Association of specific organisms with particular
    diseases
  3. Development of vaccines

34
Louis Pasteur in his laboratory
35
BIOGENESIS
  • All this eventually leads to Rudolf Virchows
    concept of BIOGENESIS
  • That all living cells can only arise from
    pre-existing living cells

36
Robert Koch (1843-1910) First proof that
bacteria actually cause some disease
37
Kochs Postulates
  1. The microbe must be present in every case of the
    disease but absent from healthy organisms
  2. The suspected microbe must be isolated and grown
    in a pure culture
  3. The same disease must result when the isolated
    microbe is inoculated into a healthy host
  4. The same microbe must be isolated again from the
    diseased host

38
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39
Techniques for Studying Microorganisms
  • Fannie Hesse suggested that agar could be used as
    a solidifying agent
  • Richard Petri developed the petri dish which was
    used to contain the solid culture media (agar and
    nutrients)
  • Robert Koch used these techniques to isolate the
    bacterium that caused tuberculosis

40
Early Contributors to Bacteriology Angelina and
Walther Hesse
41
Work Toward Controlling Infections
  1. Ignaz Phillip Semmelweis Childbirth fever
    that physicians (who did not routinely disinfect
    their hands at the time) were responsible for
    transmitting puerperal fever from one patient to
    another
  2. Joseph Lister Listerine

42
Ignaz Philipp Semmelweis (1818-1865) Depicted on
an Austrian 1965 postage stamp
43
Joseph Lister Antiseptic Surgery (1869)
44
Modern Developments
  • Bacteriology-study of bacteria, began with
    Leeuwenhoeks examination of tooth scrapings
  • Mycology-study of fungi
  • Parasitology-study of protozoa and parasitic
    worms
  • Immunology-study of the immune system, began with
    Jenners first vaccine in 1796
  • Advanced when Rebecca Lancefield classified
    Streptococcus based on differences in cell wall

45
Modern Developments continued
  • Virology- Iwanowski and the tobacco mosaic virus
    discovery in 1892 gave it a major boost
  • Recombinant DNA technology-use microorganisms to
    manufacture human hormones and other medical
    substances (growth hormone used to come from
    cadavers)
  • The technology is also called genetic engineering
  • 1944 DNA proved to be unit of heredity (Averys
    group
  • 1946 Lederberg and Tatum discovered conjugation
  • 1953 Watson and Crick created model for DNA
  • 1961 Jacob and Monod discovered mRNA leading to
    the understanding of protein synthesis

46
Emergence of Special Fields of Microbiology
  1. Immunology
  2. Virology
  3. Chemotherapy
  4. Genetics and Molecular Biology

47
Elie Metchnikoff (1845-1916) discovers
phagocytosis, which we now know is the way much
of our immune system works
48
Electron micrograph of tobacco mosaic virus (
617,000X)
49
TOBACCO MOSAIC VIRUS A helical core of RNA
surrounded by a coat consisting of repeating
protein units. The structure of the particles is
so regular that the viruses can be crystallized.
50
Paul Ehrlich (1854-1915)
51
Sir Alexander Fleming (1881-1955) discoverer of
penicillin the first antibiotic
52
Plant scientists using knowledge gained from
research
53
Fields of Microbiology
54
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55
Genetically engineered bacteria used to
investigate how diet influences cancer risk
56
Inspecting plastics made with as much as 40
starch (pieces inside baskets) for signs that
aquatic microbes are degrading them
57
DECONTAMINATE WASTES
58
Using beating nets to survey for ticks that can
spread disease to livestock and humans
59
Keeping pets and domestic animals healthy, as
well as improving their productivity, by means of
advances in veterinary science
60
The AIDS Memorial Quilt in Washington, D.C.
November 1996, the last time it was small enough
to be displayed all at once. Over 45,000 panels,
each dedicated to the memory of one victim,
covered 15 city blocks.
61
A model of the virus that causes AIDS.
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