Lecture 5, 9/10, More History, Units of Measurement and Types of Microscopes

Listen to today's lecture here!

• River’s Postulates – used to prove viruses cause disease (see class handout from 8/31)
• 1. Viral agent must be found either in the host’s body fluids at the time of the disease or in the cells showeing specific lesions
• chicken pox - vzv – verasella (chicken pox) zoster (shingles) virus. Chicken pox early on shingles later on.
• 2. disease causation – the viral agent obtained from the infected host must cause the specific disease
• 3. Similar material from such newly infected animals or plants must in turn be capable of transmitting the disease.
• 2 organisms we cant do Kochs postulates on
• Treponema pallidum – causes syphilis
• grown in testicles of rabitt
• Mycobacterium leprae – grows best in armadillos (found in southern states). Cant grow in lab
• Golden Age of microbiology 1850-1900
• Koch is known best for one organism “Koch’s Bacillus”
• Mycobacterium tuberculosis – seen primarily in AIDS patients
• Also known for
• first one to use photo microscopy – taking a picture through the lense
• lab methods – such as staining
• Vibrio cholera – fecal contamination of water - associated with Snow (first to isolate it)
• 1883 – Metchnikoff
  
• discovered phagocytosis (white blood cells engulf and destroy organisms)
• 1888 - Roux and Yersin (Yersinia pestis – associated with plague)
• Discovered exo-toxins that caused diseases.
• Botulism (Clostridum botulinum) , tetnus (Clostridium tetani), Diptheria (Corynebacterium diptheriae)
• 1892 - Ivanowsky (Beijerinck)
• Discovered viruses
• TMV – tabacco mosaic virus (a plant virus)
• 1898 - Theobold Smith
• First great American microbiologist
• best known for vectors (insect vectors: tics, lice, flees)
• 1900’s
• von Behring and Kitasato
• worked on how we respond to exo-toxins. We form anti-toxins
• DPT – our anti toxin to diptheria and tuberculosis
• Ehrlich
• chemist who worked with syphilis
• 606th compound he tried finally killed syphilis. It was an arsenical compound – a poison. Cured a few and killed a bunch.
• first to put forth a theory of antibody formation
• Lister
• Listerine is named after him.
• aseptic surgery methods – sprayed phenol, very costic (gives chemical burns)
• father of disinfectants
• Reed
• Worked on yellow fever and it’s association with mosquitoes
• Important in building of panama canal
• Rous
• RSV – discovered “Rous sarcoma virus”. first virus to develop a solid tumor in chickens
• Winogradsky, Beijerinck
• Worked out nitrogen cycle – decomposition: organic to inorganic
• Fleming
• Penicillin – miracle drug of 20th century
• Also noted for an enzyme in your eye – lysazime, which is secreted when you cry. A common defense against organisms that cause pink eye.
• Salk, Sabin
• Came up with vaccines for polio. Attenuated polio virus – alive (technique by Pasteur)
• Salk developed injectable vaccine
• Sabin developed oral(drops) vaccine
• Avery, Mcleod, McCarty
• DNA could be transformed from one organism to the other
• process today is called transformation – genetic engineering
• • Spiegelman
• First to create a virus in a test-tube (an RNA virus)
• • Kornberg
• Created first DNA virus in a test tube.
• Kornbergs enzyme: DNA polymerase
• • Watson, Krick and Wilkens
• Double helix – helped us understand replication, transcription and translation.
• Most important discovery in 20th century.
• • Baltimore and Temin
• Discovered how RNA viruses can take over a cell. They do reverse transcriptase (RT). If you have an RNA virus you can get a DNA copy. Gene therapy.
• • 1982 - Epstein and Bar virus
• EBV – causes mononucleosis. Associated with a cancer, particularly in Africa, Burketts lymphoma.
• • Kohler and Milstein
• Discovered the hybridoma technique. Put two cells together and from there they could make monoclonal antibodies (MCAB). Pure preperation of antibodies - used in therapy and diagnosis
• • Montagnier and Gallo
• Discovered what causes AIDS which is HIV
• • Arbor, Smith and Nathans
• Restriction endo nucleases which is used in recombinant DNA.
• • HOW TO VISUALIZE MICROORGANISMS
• Units of measurements
• meter=39.37inches
• centimeter (cm)=1/100m or 10^-2meters
• millimeter (mm)=1/10cm or 10^-3meters
• micrometer (um) common distance that we use to talk about bacteria=1/1000mm or 10^-6meters
• nanometer (NM) common distance that we use to talk about viruses=1/1000um or 10^-9meters
• Angstrom=1/10NM or 10^-10M
• Resolving Power (RP)=wl of light/2(Numerical Aperture)
• ability to resolve very small things
• RP: the distance between two small objects where they can be resolved as two distinct objects or the diameter of the smallest object you can see.
• =500nm/2(1.25)
• =.5um/2.5
• =.2um (this is the smallest thing we can see in the lab)
• Bright field microscopy (BF)
• max magnification – 1000x
• costs - 1000$
• can see color
• RP=0.2 um
• Dark field microscope
• Used to diagnose diseases - particularly syphilis (spirochetes)
• unique condenser that has a hallow cone of light that allows you to see the organism
• Pick up colored pencils!!!

NOTE: In case you missed it this is a link to play the audio for today's lecture. It is labeled Micronotes910