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Introductory Microbiology

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Title: Introductory Microbiology


1
Introductory Microbiology
  • Dr. Heather Townsend

2
Characteristics of Life
  • Growth and development
  • Reproduction and heredity
  • Metabolism
  • Movement and/or irritability
  • Cell support, protection, and storage mechanisms
  • Transport of nutrients and waste
  • Living things are made of cells!!

3
All cells.
  • Have an outer plasma membrane
  • Contain DNA
  • Enclosed within the cell somewhere
  • Contain cytoplasm
  • Everything between the plasma membrane and the
    region of DNA
  • Gives cells their shape
  • Assist in movement of cell and organelles

4
Characteristics of Microbes
  • Prokaryotic cells
  • Smaller
  • Lack special structures such as a nucleus and
    organelles
  • All prokaryotic cells are microorganisms
  • Some microorganisms are eukaryotic
  • Viruses?

5
Microorganisms
6
Characteristics of Cells
  • Eukaryotic cells
  • Animals, plants, fungi, and protists
  • contain double-membrane bound nucleus with DNA
  • contain membrane-bound organelles
  • 10100 µm in diameter

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Characteristics of Cells
  • Prokaryotic cells
  • 1.0 µm in diameter
  • Bacteria and archaea
  • no nucleus
  • no membrane-bound organelles

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Microbiology
  • The study of of organisms (microorganisms or
    microbes) too small to be seen without
    magnification
  • This includes
  • Bacteria
  • Viruses
  • Fungi
  • Protozoa
  • Helminths (worms)
  • Algae

13
The Microbes
  • 1. Bacteria
  • Single-celled organisms
  • Various shapes
  • Spherical
  • Rod
  • Spiral shapes
  • Cellular
  • Lack membrane-enclosed cellular structures
  • Widely distributed in nature

Klebsiella pneumoniae, bacteria that causes
pneumonia in humans
14
The Microbes
  • 2. Viruses
  • Acellular
  • Composed of nucleic acid and a few proteins
  • Replicate themselves to display other properties
    of living organisms when they invade living cells

15
The Microbes
  • 3. Fungi
  • Yeasts and molds
  • Single-celled, microscopic
  • Mushrooms
  • Multicellular, macroscopic
  • Cell nucleus and other cellular structures
  • Absorb nutrients from their environment
  • Widely distributed in water and soil
  • Act as decomposers of dead organisms

16
The Microbes
  • 4. Protozoa
  • Single-celled, microscopic organisms
  • Have at least one nucleus and many cellular
    structures
  • Obtain food by engulfing or ingesting smaller
    organisms
  • Most can move
  • Found in many different environments

Amoeba
17
The Microbes
  • 5. Helminths
  • Large, multicellular
  • Parasitize host tissues
  • Organs for reproduction, digestion, movement,
    protection
  • Mouthparts
  • Ingestion of larvae or eggs in food

Tapeworm Head
18
The Microbes
  • 6. Algae
  • Single-celled microscopic organisms
  • Have a nucleus and many membrane-enclosed
    cellular structures
  • Photosynthesize their own food
  • Widely distributed in fresh and salt water
  • Important source of food for other organisms

Micrasterias, a green algae living in fresh water
19
General cell characteristics
  • Locomotor appendages
  • External boundaries

20
External Structures of Cells
  • Locomotor appendages
  • flagella
  • long, sheathed cylinder containing microtubules
  • covered by an extension of the cell membrane
  • function in motility
  • cilia
  • similar in overall structure to flagella
  • shorter and more numerous
  • found only on a single group of protozoa and
    certain animal cells
  • function in motility, feeding and filtering

21
External Boundary Structures
  • Plasma (cell) membrane
  • typical bilayer of phospholipids and proteins
  • serves as selectively permeable barrier in
    transport

22
External Structures of Cells
  • Glycocalyx
  • an outermost boundary that comes into direct
    contact with environment
  • usually composed of polysaccharides
  • appears as a network of fibers, a slime layer or
    a capsule
  • functions in adherence, protection, and signal
    reception
  • Beneath the glycocalyx
  • Fungi and most algae - cell wall
  • Protozoa, a few algae, and all animal cells
    cell membrane

23
External Boundary Structures
  • Cell wall
  • Fungi
  • thick inner layer of polysaccharide fibers
  • composed of chitin or cellulose and a thin layer
    of mixed glycans
  • Algae
  • varies in chemical composition
  • substances include cellulose, pectin, mannans,
    silicon dioxide, and calcium carbonate
  • Bacteria!!!
  • Dependent on cell wall composition

24
Prokaryote
Eukaryote
25
Branches of Study Within Microbiology
  • Immunology
  • studies immune chemicals and cells that are
    produced in response to infection
  • Public health microbiology epidemiology
  • aim to monitor and control the spread of diseases
    (CDC)
  • Food, dairy and aquatic microbiology
  • examine the ecological and practical roles of
    microbes in food and water
  • Biotechnology
  • ranges from bread making to gene therapy
  • Genetic engineering recombinant DNA technology
  • altering the genetic makeup of organisms

26
Microbes Are Involved In
  • nutrient production energy flow
  • i.e., photosynthesis
  • decomposition and nutrient recycling
  • production of foods, drugs vaccines
  • bioremediation
  • causing disease

27
Impact of Pathogens
  • Pathogens
  • Diseases-causing agents
  • Nearly 2,000 different microbes cause diseases in
    the human body
  • 10 B infections/year worldwide
  • 13 M deaths from infections/year worldwide
  • killing about 1/3 of the U.S. population each
    year

28
Impact of Pathogens
  • Emerging diseases
  • Becoming more prominent over the years
  • Zoonosis
  • SARS
  • Reemerging
  • Older diseases increasing in occurrence
  • TB
  • Malaria
  • Hepatitis

29
Historical Microbiology
  • 1546 physician suggest that invisible organisms
    may be involved with disease
  • Abiogenesis vs biogenesis

30
Early Microbiologists
  • Antonie van Leeuwenhoek
  • 1676
  • First to observe living microbes
  • His single-lens magnified up to 300X

31
Early Medical Microbiology
  • Francesco Redi
  • 1688
  • Spontaneous generation
  • Living things arise from nonliving things
  • Belief that some forms of life could arise from
    vital forces present in nonliving or decomposing
    matter
  • Debate over spontaneous generation led in part to
    development of scientific method

32
Science
  • Scientific method
  • 1. Observe some aspect of the natural world and
    ask questions about it
  • 2. Hypothesis
  • 3. Make predictions
  • 4. Test the predictions
  • 5. Repeat the tests or develop new ones
  • 6. Analyze and report the test results and
    conclusions

33
Early Medical Microbiology
  • Oliver Wendell (American physician) 1837
  • observed mothers who gave birth at home
    experienced fewer infections than those that gave
    birth in a hospital
  • Ignaz Semmelweis (Hungarian doctor) 1850
  • showed that women became infected with puerperal
    fever during delivery by doctors coming directly
    from the autopsy room

34
Early Medical Microbiology
  • Louis Pasteur - 1861
  • Worked in the wine industry
  • Had knowledge about yeast producing alcohol
  • Swan-neck flasks
  • Tipping the flask would allow the microbes to
    enter the infusion
  • Cause them to become cloudy
  • Main experiment that helped disprove spontaneous
    generation
  • Developed Pasteurization
  • Developed a rabies vaccine

35
Early Medical Microbiology
  • Joseph Lister (English surgeon) 1865
  • Introduced aseptic techniques
  • Aimed at reducing microbes in a medial setting
    and preventing wound infections
  • Improved sanitation
  • Promotes use of carbolic acid on bandages and
    medical instruments

36
Early Medical Microbiology
  • Robert Koch (German) 1871
  • Linked a microscopic organism with a specific
    disease (anthrax)
  • Developed method to grow bacteria in pure
    cultures (cultures containing only one kind of
    organism)
  • Used solidified gelatin from potato slices mixed
    with agar
  • Creates a firm surface that microbes could grow
    on

37
Kochs Postulates
  1. The specific causative agent must be found in
    every case of the disease
  2. The disease organism must be isolated in pure
    culture
  3. Inoculation of a sample of the culture into a
    healthy, susceptible animal must produce the same
    disease
  4. The disease must be recovered from the inoculated
    animal

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germ theory of disease
  • pathogenic theory of medicine
  • Proposes that microorganisms are the cause of
    many diseases
  • Controversial, but validated in late 19th century

40
1900s and beyond..
  • Paul Ehrlich 1900
  • First to use dyes to ID bacteria
  • Named concept of chemotherapy
  • Treatment for syphilis
  • magic bullet
  • Compound could be made to selectively target a
    disease-causing organism

41
1900s and beyond
  • Alexander Fleming 1929
  • observed that a species of Penicillium mold
    killed bacterial cells
  • led to the development of penicillin
  • Two types of cells recognized!!!

42
MicrobiologyNow
  • Microbiology continues to face many challenges
  • A pathogen can cause more than one disease
  • Pathogens are becoming resistant to
    antimicrobials
  • Pathogens can be used intentionally to infect
    large numbers of people through bioterrorism

43
Microscopy
  • Micrometer Size Range
  • Most bacterial and archaeal cells are 1-5
    micrometers (µm) in length

44
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How to view microbes?
  • Light Microscopy
  • Visible light passes through multiple lenses and
    through the specimen
  • Light microscopes usually have at least 3 lenses
  • Scanning (4X)
  • low-power (10X)
  • high-power (45X)
  • oil-immersion (100X)

46
How to view microbes?
  • Staining techniques
  • simple stain technique
  • negative stain technique
  • Special stains

47
Taxonomy
  • Organizing, classifying and naming living things
  • In the mid-1700s, Carolus Linnaeus published
    Systema Naturae, establishing a uniform system
    for naming organisms
  • Nomenclature gives scientific names to organisms
  • Identifying and classifying organisms according
    to specific criteria

48
Taxonomy
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • species

49
3 Domains
  • Eubacteria
  • true bacteria
  • peptidoglycan
  • Archaea
  • odd bacteria that live in extreme environments
  • high salt, heat, etc. (usually called
    extremophiles)
  • Eukarya
  • have a nucleus organelles
  • Protista
  • Algae
  • Fungi
  • Plantae
  • Animalia

50
Naming Most Micoorganisms
  • Binomial (scientific) nomenclature
  • Gives each microbe 2 names
  • Genus - noun, always capitalized
  • species - adjective, lowercase
  • Both italicized or underlined
  • Staphylococcus aureus (S. aureus)
  • Bacillus subtilis (B. subtilis)
  • Escherichia coli (E. coli)

51
Microorganisms in history.
  • Edward Jenner
  • Smallpox vaccine
  • Tested it on his son and neighborhood children
  • Japan
  • Plague infected fleas covered with cholera
  • Tuskegee Syphilis experiment
  • 1932 - 1972
  • Guatemala's National Mental Health Hospital -
    1946
  • US Infected patients with syphilis
  • Vector - prostitutes

52
Microorganisms in history
  • University of PA 1950
  • Infected 200 female prisoners with hepatitis
  • Biological warfare
  • CIA whooping cough in FL 12 killed
  • US Army mosquitoes in South
  • Plum Island, NY
  • Lyme Disease??

53
What to expect..
  • Different microorganisms
  • How to detect microorganisms
  • Common disease caused by microorganisms
  • How to control the spread of microorganisms
  • Immune system
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