history and scope
TRANSCRIPT
HISTORY AND SCOPE OF MICROBIOLOGY
Dr.D.Arvind Prasanth
History
• 1665 Robert Hooke observed living plant tissues (20X mag.)
• “Little boxes” or Cells
• Used simple magnifying lens
• Suggested all living things are made of cells
Hooke's Microscope
1665
Antonie van Leeuwenhoek
was inspired by this
publication
Antonie van Leeuwenhoek(1677) (“layu-wen-hook”)
–First observation of living cells (200-300X mag.)
–“Animalcules”
–Single lens Microscope (Self made)—simple microscope
–Tooth plaque
–Rain water
–Diarrheal feces
Antonie van Leeuwenhoek
• Bacteria• Protozoa• Sperm cells• Blood cells• Microscopic
worms
Antonie van Leeuwenhoek’s
microscope
3-4” microscope
Required good
lighting and
patience
Spontaneous Generation
• The idea that life could arise spontaneously from nonliving matter
–Ex: Toads and Mice could arise from soil
–Until the 18th century this believe existed
History (cont.)
• 1668 Francesco Redi
–1st one to disprove spontaneous generation
Francesco Redi’s experiments with meat
uncovered covered
Maggots No maggotsDisproved that maggots arise from decaying meat!!
• Proved (??) spontaneous generation in chicken broth
• Heated Nutrient Fluids and poured them into covered flasks
British clergyman John Needham’s experiments (1745)
Hot Mutton
gravy
Turbid
broth
“...my phial swarm’d with life...”
Italian priest Lazzaro Spallanzani (1765)
• Similar to Needham’s Experiments
• He showed that heating a sealed flask of meat broth prevented growth of organism
• Skeptics claimed—lack of O2prevented growth!!
The Golden Age of Microbiology!
•Louis Pasteur (finally disproved
spontaneous generation after many years
of debate)
•Robert Koch (proof of germ theory)
•Other pioneers in Microbiology
Pasteur—Father of microbiology
•1857- Louis Pasteur saves France’s wine
industry
•Napoleon III begged Pasteur (a chemist
by training) to help solve a problem
•Sailors were mutinying b/c their wine
was spoiling after only a few weeks at sea
•Pasteur armed with his trusty
microscope accepted the challenge
Louis Pasteur
–Spontaneous Generation finally disproved
–Boiled broth in long-s-shaped necked flasks (unsealed)
•Remained sterile
•Proved that microorganisms are present in air, but air does not createmicrobes
–Beginning of the golden age of microbiology
Louis Pasteur (1861)
Swan neck flask experiment disproved spontaneous generation(1861)
History (cont.)• 1861 Pasteur
–Proved Microorganisms are present in
nonliving matter
–Microbes can be destroyed by heat
•Aseptic Technique
• Fermentation mediated by yeast, not air
–Pasteurization to prevent wine and beer
spoilage (by bacteria)
1857-Louis Pasteur saves France’s wine
1)Good wine contained yeast
2)Sour wine contained bacterium (Bacteria
that use alcohol and produce acetic acid spoil wine by turning it to
vinegar (acetic acid).
3)He reasoned that if wine is heated to
destroy the harmful bacteria it
wouldn’t spoil (process known as
Pasteurization)
Pasteur’s Tomb in the Crypt of the Pasteur Institute in Paris
Germ Theory of Disease
• Pasteur proposed that wine spoiling in an analogy for disease (bacterial growth made the wine “sick”)
• He hypothesized in 1857 that microorganisms are responsible for infectious diseases
Edward Jenner (country doctor)– Milkmaid didn’t get smallpox b/c they
contracted the milder form of cowpox
– Immune system cannot distinguish btw cowpox/smallpox
– Scratched a farmboy w/ a needle bearing fluid from cowpox
– Small pox Vaccine
- -Vacca-cow
- Vaccination w/ cowpox provided immunity for smallpox
Protection from a
disease from
vaccination
Immunity
Robert Koch (1843-1910)
• German country physician who developed microbiology into a science
• Developed pure culture techniques (used potato slices to grow bacteria) developed agar later on
• Proof of the germ theory
• Work with anthrax
• Koch’s postulates
Bacillus anthracis
Pure Culture Key to Studying
Microbes
Definition: Pure culture is a
population of organism, all of which
are the progeny of a single organism
-In nature, microbes almost never
occur as pure cultures
AGAR•Is a complex polysaccharide derived from
seaweed
•Was suggested by Fannie Hesse wife of
Koch’s co-worker Walther Hesse•“why do your jellies and pudding stay solid in warm weather”?
•AGAR-AGAR had been used as a gelling
agent in Asia for centuries
•Fannie learned to use AGAR-AGAR from a
Dutch neighbor in New York who spent time in
Asia
Koch’s postulates
1)Specific microorganism is present in all
cases of the disease
2)Organism can be obtained in pure
culture outside of the host
3)Organism when re-inoculated into host
causes the same symptoms
4)Organism can be isolated in pure culture
from experimentally infected host
Koch’s findingsKoch and his coworkers discovered that
bacteria caused
•TUBERCULOSIS
•CHOLERA
•DIPTHERIA
•TYPHOID FEVER
•GONORRHEA
•PNEUMONIA
Paul Ehrlich-hospital dermatologist
• Chemotherapy-Treatment using chemical substances
• 1910 Paul Ehrlich -”Magic bullet”
–Salvarsan (arsenic derivative)
•Preparation 606
–Syphilis
Alexander Fleming –scottish researcher--1928
• Discovered Penicillin (fungus) by accident
• Was convinced that nasal mucus had antibacterial effects
• Left his Staphylococcus culture on an agar plate for 2 weeks-went on vacation-came back &found mold on his plate which prevented bacterial growth (a mycology lab underneath him had this rare spore drift)
Founders of Microbiology (Review)
•First observed microbes—
Leeuwenhoek
•Proved living cells can arise only from
other living cells---Pasteur
•Confirmed the Germ Theory of Disease
--Koch
Scope of microbiology
Bacteria
• Medical importance
–Gastroenteritis
–Syphilis
–Tetanus
–Lyme disease
–Plague
Bacteria (cont.)
• Industrial importance
–Food supplements
•Amino acids & Vitamins
–Organic solvents
•Acetone
Bacteria (cont.)
• Pharmaceutical importance
–Antibiotics
•polymyxin
–Hormones
•Insulin
Biotechnology and Recombinant DNA
• Biotechnology:
–The use of microorganisms, cells, or
cell components to make a product
–Foods, antibiotics, vitamins, enzymes
• Recombinant DNA Technology:
–Insertion or modification of genes to
produce desired proteins
Bacteria (cont.)• Environmental importance
–Biodegradation
•Oil spills
•Wastewater treatment
Gram positive
S. aureus
Gram negative
E. coli
Fungi
• Medical importance
–Valley fever
–Candidiasis
–Athlete's foot
Fungi (cont.)
• Industrial importance
–Fermentation
•Wine
•Beer
•Bread
Fungi (cont.)
• Pharmaceutical importance
–Antibiotics
•Penicillin
Fungi (cont.)
• Environmental importance
–Wastewater treatment
–Degradation of complex
organic matter
•Lignin in wood
Viruses
• Medical importance
–HIV
–Influenza
–Rabies
–Common cold