What is a Microbe

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What is a Microbe

• Smaller than 0.1mm
• Includes bugs, things, germs, viruses, protozoan,
  bacteria, animalcules, small suckers

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Nomenclature

• Carolus Linnaeus (1735)
• Genus species
• By custom once mentioned can be abbreviated with
  initial of genus followed by specific epithet
• When two organisms share a common genus this may
  indicate relatedness.

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Why study Microbiology

• Microbes are related to all life.
• In all environments
• Many beneficial aspects
• Related to life processes (food web, nutrient
  cycling)
• Only a minority are pathogenic.
• Most of our problems are caused by microbes

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EIDs

• Emerging infectious diseases
• Weapons of mass destruction
• New evolutionary features
• Response to encroaching on the environment
• Can you name an example?

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Microbes in research

• 10 trillion human cells 10x this number microbes
• Easy to grow
• Biochemistry is essentially the same
• Simple and easy to study

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Biotechnology

• Use of biological systems to produce useful items
• The use of biological information to make things
  or improve the human condition

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Diversity of Microbes

• Bacteria-single celled prokaryotes
• Protozoa-eukaryotic, single celled, colonial,many
  ways of nutrition
• Fungi- absorb nutrients, single celled
  filamentous
• Viruses-acellular entities
• Others- worms, insects

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Bacteria

• Prokaryotes
• Peptidoglycan cell walls
• Binary fission
• For energy, use organic chemicals, inorganic
  chemicals, or photosynthesis

Figure 1.1a
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Archaea

• Prokaryotic
• Lack peptidoglycan
• Live in extreme environments
• Include
• Methanogens
• Extreme halophiles
• Extreme thermophiles

Figure 4.5b
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Fungi

• Eukaryotes
• Chitin cell walls
• Use organic chemicals for energy
• Molds and mushrooms are multicellular consisting
  of masses of mycelia, which are composed of
  filaments called hyphae
• Yeasts are unicellular

Figure 1.1b
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Protozoa

• Eukaryotes
• Absorb or ingest organic chemicals
• May be motile via pseudopods, cilia, or flagella

Figure 1.1c
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Algae

• Eukaryotes
• Cellulose cell walls
• Use photosynthesis for energy
• Produce molecular oxygen and organic compounds

Figure 1.1d
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Viruses

• Acellular
• Consist of DNA or RNA core
• Core is surrounded by a protein coat
• Coat may be enclosed in a lipid envelope
• Viruses are replicated only when they are in a
  living host cell

Figure 1.1e
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Multicellular Animal Parasites

• Eukaryote
• Multicellular animals
• Parasitic flatworms and round worms are called
  helminths.
• Microscopic stages in life cycles.

Figure 12.28
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The Scientific Method

• Make an observation
• Make a hypothesis
• Test the hypothesis
• Draw your conclusions
• repeat

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Requirements for Scientific methods

• Single variables
• Experimental controls
• How can this be used to discover things?
• Does HIV cause AIDS??? Discuss

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Knowledge of microorganisms

• Allows humans to
• Prevent food spoilage
• Prevent disease occurrence
• Others?
• Led to aseptic techniques to prevent
  contamination in medicine and in microbiology
  laboratories.

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Universal precautions set up by CDC

• Use gloves, gowns, masks and goggles
• Minimize risk of needle sticks
• Disinfections procedure
• Preventative treatment after exposure
• Reduce risk
• Treat all patients the same
• HBV greater risk than HIV

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The Debate Over Spontaneous Generation

• The hypothesis that living organisms arise from
  nonliving matter is called spontaneous
  generation. According to spontaneous generation,
  a vital force Forms life.
• The Alternative hypothesis, that the living
  organisms arise from preexisting life, is called
  biogenesis.

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Evidence Pro and Con

• 1668 Francisco Redi filled six jars with
  decaying meat.

Conditions Results
3 jars covered with fine net No maggots
3 open jars Maggots appeared
From where did the maggots come? What was the purpose of the sealed jars? Spontaneous generation or biogenesis? From where did the maggots come? What was the purpose of the sealed jars? Spontaneous generation or biogenesis?
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Evidence Pro and Con

• 1765 Lazzaro Spallanzani boiled nutrient
  solutions in flasks.

Conditions Results
Nutrient broth placed in flask, heated, then sealed No microbial growth
Spontaneous generation or biogenesis? Spontaneous generation or biogenesis?
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The Theory of Biogenesis

• Pasteurs S-shaped flask kept microbes out but
  let air in.

Figure 1.3
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Where is Microbiology currently being practiced?
I.e. jobs

• Put your Choice here

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A timeline of Microbiology

• Fig 1.4
• Some highlights
• 1665 Hooke
• 1673 van Leeuwenhoeks microsopes
• 1735 Linnaeus Nomenclature
• 1798 Jenner vaccine
• 1857 Pasteur Fermentation
• 1876 Koch germ theory of disease

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The Golden Age of Microbiology

• 1857-1914
• Beginning with Pasteurs work, discoveries
  included the relationship between microbes and
  disease, immunity, and antimicrobial drugs

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Fermentation and Pasteurization

• Pasteur showed that microbes are responsible for
  fermentation.
• Fermentation is the conversation of sugar to
  alcohol to make beer and wine.
• Microbial growth is also responsible for spoilage
  of food.
• Bacteria that use alcohol and produce acetic acid
  spoil wine by turning it to vinegar (acetic acid).

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Fermentation and Pasteurization

• Pasteur demonstrated that these spoilage bacteria
  could be killed by heat that was not hot enough
  to evaporate the alcohol in wine. This
  application of a high heat for a short time is
  called pasteurization.

Figure 1.4
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The Germ Theory of Disease

• 1835 Agostino Bassi showed a silkworm disease
  was caused by a fungus.
• 1865 Pasteur believed that another silkworm
  disease was caused by a protozoan.
• 1840s Ignaz Semmelwise advocated handwashing to
  prevent transmission of puerperal fever from one
  OB patient to another.

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The Germ Theory of Disease

• 1860s Joseph Lister used a chemical disinfectant
  to prevent surgical wound infections after
  looking at Pasteurs work showing microbes are in
  the air, can spoil food, and cause animal
  diseases.
• 1876 Robert Koch provided proof that a bacterium
  causes anthrax and provided the experimental
  steps, Kochs postulates, used to prove that a
  specific microbe causes a specific disease.

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The Birth of Modern Chemotherapy

• Treatment with chemicals is chemotherapy.
• Chemotherapeutic agents used to treat infectious
  disease can be synthetic drugs or antibiotics.
• Antibiotics are chemicals produced by bacteria
  and fungi that inhibit or kill other microbes.
• Quinine from tree bark was long used to treat
  malaria.
• 1910 Paul Ehrlich developed a synthetic arsenic
  drug, salvarsan, to treat syphilis.
• 1930s Sulfonamides were synthesized.

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The Birth of Modern Chemotherapy

• 1928 Alexander Fleming discovered the first
  antibiotic.
• He observed that Penicillium fungus made an
  antibiotic, penicillin, that killed S. aureus.
• 1940s Penicillin was tested clinically and mass
  produced.

Figure 1.5
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Modern Developments in Microbiology

• Bacteriology is the study of bacteria.
• Mycology is the study of fungi.
• Parasitology is the study of protozoa and
  parasitic worms.
• Recent advances in genomics, the study of an
  organisms genes, have provided new tools for
  classifying microorganisms.

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Selected Novel Prizes in Physiology or Medicine
1901 von Behring Diphtheria
antitoxin 1902 Ross Malaria
transmission 1905 Koch TB bacterium 1908 Metchniko
ff Phagocytes 1945 Fleming, Chain,
Florey Penicillin 1952 Waksman Streptomycin 1969 D
elbrück, Hershey, Luria Viral replication 1987 Ton
egawa Antibody genetics 1997 Prusiner Prions

• The first Nobel Prize in Physiology or Medicine.

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Principles of Microscopy

• Metric units (table 3.1)
• Micrometer
• Nanometer
• angsrom

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Compound light microscopy

• Basic parts
• Eyepieces (ocular lens)
• Base
• Condenser
• Iris diaphragm
• Objective lens
• Body tube
• Mechanical stage
• Adjustment knobs

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Magnification

• Calculation
• Objective power x ocular power total power
• Parafocial
• Paracentric
• Microscopic measurement
• Micrometer? Why must we calibrate it?

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What you should know?

• What are microbes?
• What types of microbes?
• Some history Highlights
• The Magic Bullet
• Microbes and human Welfare
• Microbes and Human Disease
• The CDC