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Jospeh Lister
Pioneered use of carbolic acid spray in the OR
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Ignaz Semmelweis
Pioneered hand washing techniques
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Pasteurization
Reduction of food spoilage organisms by heating
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Anthrax
- Koch studied antrax
- Inhaled anthrax affects the lungs
- Anthrax is caused by Bacillus anthracis
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Koch's Postulates
- A process to determine the etiology (cause) of an infectious disease.
- 1. The suspected pathogen must be found in all cases of the disease, but not in healthy individuals
- 2. The suspected pathogen must be isolated from a diseased host and grown in pure culture
- 3. The pure culture must produce the same symptoms when inoculated into a healthy host
- 4. The same pathogen must be isolated from the secondary host
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Exceptions to Koch's Postulates
- 1. Some pathogens cannot be grown in pure culture
- 2. Many pathogens are species-specific: there may be no animal models for a human disease
- 3. Some pathogens can persist
- in “carriers” who have no symptoms
- 4. Some microorganisms can cause more than one disease
- 5. Some diseases (sets of symptoms) have more than one cause
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Medical Microbiology
- 1. Identify the causative agent (Koch’s Postulates)
- 2. Cure or prevent the disease
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Early Vaccination
- Lady Mary Montagu
- “inoculation parties”
- “customers” would have a scratch made on a limb
- Pus from the victim of a mild attack of smallpox would be smeared on open vein of customer
- Worked most of the time
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Edward Jenner
- Jenner 1798. Cowpox pustule material protects humans from small pox
- Vaccination after vacca which means cow.
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Pasteur with Vaccination
- Rabies vaccination
- Basic idea: pre-exposure to weakened pathogen later protects from the active pathogen.
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Progression of viruses
- ~1930 The name viruses (poison) coined
- ~1940 Electron microscope developed and viruses observed for the first time
- ~1950 Viruses are obligate intracellular pathogens – must be grown in live organisms, or in tissue culture
- ~1960 antibodies discovered – specific antibodies can be used to identify specific viruses
- ~1970s onwards. Molecular techniques –
- DNA, RNA or protein analysis- used to detect presence of viruses
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Modification of Koch’s Postulates for use with viruses
- Postulate 1:
- Viral particles, viral proteins, viral nucleic acids or antibodies specific to the virus are present in infected individuals and not present in uninfected individuals
- Postulate 2:
- Viruses can be grown in tissue culture, or observed in infected tissues under the EM
- Postulate 3:
- Cell-free filtrates of infected material produce disease in animal models (if available) or in tissue culture
- Postulate 4:
- Viral particles from second host look the same, and have the same molecular characteristics as the original isolate.
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Virus Causation and Cure
- If a certain virus is consistently associated with a certain disease AND
- Methods used to prevent transmission of that virus reduce incidence of the disease OR
- A vaccine prepared using the virus prevents the disease
- Then the virus is considered to be the causative agent
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Atoms
- Are the smallest unit of matter
- Nucleus contains:
- Protons (1+) charge. Number of protons determines which atom
- Neutrons (no charge) add weight to nucleus
- Electrons (-1) charge orbit the nucleus; only part involved in chemical reactions
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Oribitals
When atoms orbitals are not filled, they are reactive
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Chemical Bonds
- Atoms can fill their orbitals by sharing electrons with another atom
- A shared electron pair is called a covalent bond
- When 2 or more atoms are bonded together, a molecule is created
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Ionic Bonds
Electrons are given away and taken away.
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Nonpolar Bonds
- Electrons are shared equally
- "Not" pulling
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Polar Bonds
- Unequal sharing of electrons
- "Pulling"
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Properties of Water
- Cohesion: water sticks to itself
- Adhesion: water sticks to other polar substances "adhesive"
- Solvent: Water is a good solvent for polar substances. Water will not dissolve in nonpolar substances. There are no charges to attract water
- High Specific Heat
- Water Density-causes lattice formation. Expands as a solid.
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Carbon-Based Life Forms
- Cells are roughly 70% water
- Dry weight of cell is mainly Carbon
- Carbon is NOT a major constituent of the earth
- It is life’s building block because of its unique structure
- C can make up to 4 highly stable covalent bonds
- C can make single, double, or triple bonds
- C can make long stable chains with itself
- C also binds to life’s other elements (H, O, N, S, Phosphate)
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Carbon bonds to other life elements
- These bonds are polar
- These bonds are not as stable as C-C or C-H bonds
- These bonds are thus reactive
- Life is not inert!
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Carbon Compounds
- Carbohydrates
- Lipids
- Proteins
- Nuclei Acids
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Carbohydrates
- Building block is glucose (sugar)
- Formed by dehydration reactions
- Two together create disaccharides
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Polysaccharides
- Long chains of sugars are called polysaccharides
- Function as energy storage or structure
- Examples include:
- Starchstorage
- Chitinstructure
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Lipids
- Building block is often glycerol
- To which Fatty Acid chains are attached
- Formed by dehydration synthesis
- Lipids are important as:
- Energy storage:
- Insulation:
- Thermal
- Electrical
- Building blocks of membranes
- Building block of steroids
- Fat-soluble vitamins (A, D, E, K)
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Lipid Structure
- Many lipids usually found as Fatty Acids (16-18 Cs)
- Lipids are either saturated or unsaturated
- Saturated refers to having as many Hs bonded to the Cs as possible
- Unsaturated have double bonds between Cs
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Phospholipid
- Phospholipids
- 2 fatty acid chains and a phosphate head
- Amphipathic
- Building block of membranes
- Phospholipids form bilayers
- Degree of unsaturation determines membrane fluidity
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Proteins
- Anything that happens in the cell is due to protein
- Proteins function:
- Structure
- Transport
- Protection/Defense
- Control/regulation
- Catalysis
- Movement
- Storage
- Amino Acid Building Block
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Amino Acids
- 20 different amino acids
- Linked by Peptide bonds which are very strong
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Levels of Protein Structure
- Primary Structure: “spelling” ; actual amino acids present, the polypeptide chain
- Secondary structure: local folding pattern; α helix, β sheet, turns
- Tertiary structure: overall 3D fold; usually a mixture of secondary structure
- Quaternary structure: 2 or more protein subunits come together to make one protein
- Primary Structure determines Tertiary Structure
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