Microbiology

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Microbiology

• MCB 2010C
• Chapter 1

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What is Microbiology?

• Micro - too small to be seen with the naked eye
• Bio life
• -ology - study of

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Brain-eating bug Researchers target Florida's
killer amoeba Orlando Sentinel April 06 2011
Life Cycle Stages of Naegleria fowleri
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True or False?

• We have identified most microbes.
• Most microbes are potentially harmful to humans
  or animals.
• When we are healthy, our bodies do not contain
  any microbes

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What are Microorganisms?

• Diverse group of organisms
• Small size (Most are microscopic)
• Relative simplicity of structure and organization
• Can be single-celled or multi-cellular
• Perform same functional activities as higher
  multicellular organisms.

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Microorganisms
Figure 1.1
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Major Groups of Microbes
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Bacteria

• Prokaryotic
• Unicellular
• Cell walls contain peptidoglycan.
• Multiply by binary fission
• 3 basic shapes, rods, cocci or spirals
• Bacteria -like prokaryotes are the
• earliest living organisms
• (3.5 billion years ago)
• For energy, use organic chemicals, inorganic
  chemicals, or photosynthesis
• May cause disease.

Eschericia coli (rod shaped)
Staphylococcus aureus (cocci)
Leptospira (spiral)
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Archaea

• Prokaryotic
• Lack peptidoglycan
• Do not cause disease
• 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
• Yeasts are unicellular
• Source of some antibiotics
• Decomposers
• May cause disease

Yeast Cells Budding (reproducing)
Penicillium (mold)
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Protozoa

• Unicellular eukaryotes
• Absorb or ingest organic chemicals
• May be motile via pseudopods,
• cilia, or flagella
• May cause disease

Amoeba proteus streaming and engulfing a
paramecium
Figure 1.1c
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Algae

• Eukaryotes
• Cellulose cell walls
• Use photosynthesis for energy
• Produce molecular oxygen and organic compounds
• Important food source for other organisms
• Do not cause disease.

Figure 1.1d
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Multicellular Animal Parasites

• Eukaryote
• Multicellular animals
• Parasitic flatworms and round worms are called
  helminths.
• May cause disease

Figure 12.28a
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Viruses

• Acellular NOT CELLS !
• Genetic information RNA or DNA surrounded by a
• protein coat).
• Obligate internal parasites (require host cells
  to reproduce).
• Submicroscopic .
• Many cause disease.

HIV
H1N1
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Size of things
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We live in their world!

• Microorganisms are the most dominant organisms
  on earth.
• Most co-exist with (commensally) or are
  useful to humans.
• Very small percentage are pathogenic to humans .
• They were here before us!

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Evolutionary Timeline
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The impact of microorganisms on human affairs
Agriculture
Energy/ Environment

• N2 Fixation (N2 2NH3)
• Nutrient Cycling- Carbon, Nitrogen and sulfur.
• Animal husbandry

• Biofuels
• Fermentation
• Corn Ethanol

• Bioremediation
• O2
• (Spilled oil CO2)

• Mining (Cu)

Food

• Food preservation
• (heat, cold, radiation,
• chemicals)

• Fermented
• foods

• Food additives
• (Citric acid, yeast)

Cellulose broken down in rumen of cattle and sheep
Biotechnology
Disease

• Genetically modified organisms
• Production of pharmeceuticals
• (insulin and other human proteins)
• Gene therapy for certain diseases

• Identify new disease
• Treatment, cure and
• prevention.

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Microbes and Human Welfare

• Microbial ecology
• Bacteria recycle carbon, nutrients, sulfur, and
  phosphorus that can be used by plants and animals.

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Bioremediation

• Bacteria degrade organic matter in sewage.
• Bacteria degrade or detoxify pollutants such as
  oil and mercury.

UN 2.1
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Modern Biotechnology and Genetic Engineering

• Biotechnology, the use of microbes to produce
  foods and chemicals, is centuries old.
• Genetic engineering is a new technique for
  biotechnology. Through genetic engineering,
  bacteria and fungi can produce a variety of
  proteins including vaccines and enzymes.

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Modern Biotechnology and Genetic Engineering
(continued)

• Missing or defective genes in human cells can be
  replaced in gene therapy.
• Genetically modified bacteria are used to protect
  crops from insects and from freezing.

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Microbes and Human Disease

• Bacteria were once classified as plants giving
  rise to use of the term flora for microbes.
• This term has been replaced by microbiota.
• Microbes normally present in and on the human
  body are called normal microbiota.

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Normal Microbiota

• Normal microbiota prevent growth of pathogens.
• Normal microbiota produce growth factors such as
  folic acid and vitamin K.

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Infectious Diseases

• Resistance is the ability of the body to ward off
  disease.
• Resistance factors include skin, stomach acid,
  and antimicrobial chemicals.
• When a pathogen overcomes the hosts resistance,
  disease results.
• Emerging infectious diseases (EID) New diseases
  and diseases increasing in incidence.

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Emerging Infectious Diseases

• Escherichia coli O57H7
• Toxin-producing strain of E. coli
• First seen in 1982
• Leading cause of diarrhea worldwide

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Emerging Infectious Diseases

• Invasive group A Streptococcus
• Rapidly growing bacteria that cause extensive
  tissue damage
• Increased incidence since 1995

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Emerging Infectious Diseases

• Swine Flu
• Influenza A virus (H1N1)
• Current epidemic occuring
• Vaccine available

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Emerging Infectious Diseases

• Acquired immunodeficiency syndrome (AIDS)
• Human immunodeficiency virus (HIV)
• First identified in 1981
• Worldwide epidemic infecting 44 million people
  14,000 new infections every day
• Sexually transmitted disease affecting males and
  females
• In the United States, HIV/AIDS cases 30 are
  female and 75 are African American

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Infectious Disease
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A Brief History of Microbiology

• Ancestors of bacteria were the first life on
  Earth.
• The first microbes were observed in 1673.

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The First Observations

• In 1665, Robert Hooke reported that living things
  were composed of little boxes or cells
  Cell Theory
• Cell theory All living things are composed of
  cells and come from preexisting cells.

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The First Observations

• 1673-1723, Leeuwenhoek
• invented the first microscope (1673)
• achieved 300x magnification
• observed bacteria and protozoa (animalcules)

Figure 1.2b
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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.

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Evidence Pro and Con

• 1745 John Needham put boiled nutrient broth into
  covered flasks.

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Evidence Pro and Con

• 1765 Lazzaro Spallanzani boiled nutrient
  solutions in flasks.

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Evidence Pro and Con

• 1861 Louis Pasteur demonstrated that
  microorganisms are present in the air.

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The Theory of Biogenesis Proven

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

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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 conversion 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.
• Pasteruization is the application of a high heat
  for a short time.

Figure 1.4 (1 of 3)
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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 proved that a bacterium causes
  anthrax and provided the experimental steps,
  Kochs postulates, to prove that a specific
  microbe causes a specific disease Germ
  theory of disease.
• Kochs Postulates
• 1. Observe same organism in all diseased
  but no healthy individuals.
• 2. Isolate microbe in pure culture on
  artificial media.
• 3. Inoculate healthy host with pure culture
  and get the same disease.
• 4. Re-isolate the same organism from
  infected host.

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Taxonomy

• Levels of Classification
• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus Binomial
• 
  System
• Species

Binomial naming system - Genus species
example Escherichia coli or E. coli or
Escherichia coli.
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Naming and Classifying Microorganisms

• Linnaeus established the system of scientific
  nomenclature.
• Each organism has two names the genus and
  specific (species) epithet (name).

• Are italicized or underlined. The genus is
  capitalized and the specific epithet is lower
  case.
• Are Latinized and used worldwide.
• May be descriptive or honor a scientist.

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Examples of Scientific Names

• Staphylococcus aureus
• Describes the clustered arrangement of the cells
  (staphylo-) and the golden color of the colonies
  (aur-).

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Examples of Scientific Names

• Escherichia coli (E. coli)
• Honors the discoverer, Theodor Escherich, and
  describes the bacteriums habitatthe large
  intestine or colon.