History of microbiology

1. Microbiology

3. UNIT 1
History and Significance of Microbiology

4. • It is estimated that microbes contain 50% of the biological carbon and 90% of the
biological nitrogen on Earth.
• Found everywhere; geothermal vents in the ocean depths; arctic ice; skin
• Microbiology often has been defined as the study of organisms and agents too small to
be seen clearly by the unaided eye—that is, the study of microorganisms.
• However, some microorganisms, particularly some eukaryotic microbes, are visible
without microscopes. For example, bread molds and filamentous algae are visible to the
naked eye, as are the two bacteria Thiomargarita and Epulopiscium.

5. What is Microbiology?
Microbes, or microorganisms are minute living
things that are usually unable to be viewed with the
naked eye.
What are some examples of microbes?
Bacteria, fungi, protozoa, algae, viruses
Some are pathogenic
Many are beneficial

6. Microbiology defined as the study of organisms
too small to be seen with the naked eye. These
organisms include viruses, bacteria, algae, fungi,
and protozoa.
Microbiologists are concerned with characteristics
and functions such as morphology, cytology,
physiology, ecology, taxonomy, genetics, and
molecular biology.
Defining Microbiology

7. Microbes make the Universe
• There are > 5 x 1030 types
Microbes in the world
• Humans have intimate
relation with Microbes >
90% of the cells in our
Body are Microbes

8. History of Microbiology
1674, Antoni van
Leeuwenhoek
(Dutch) described
live
microorganisms
that he observed in
teeth scrapings,
rain water, and
peppercorn
infusions.

9. Anton van Leeuwenhoek 1674
- 1st person to actually see living microorganisms
“wee animalcules”
（Leeuwenhoek）1632-1723

10. Louis Pasteur
1922 - 95
• Contributed best in Microbiology
• Sterilization
• Hot Air oven
• Autoclave
• Anthrax vaccine
• Rabies vaccine
• Built the Pasteur Institute
(founded- 4th June 1887,
Inaugurated- 14th Nov 1888)

11. Louis Pasteur
• Louis Pasteur considered the
father of Modern
Microbiology

12. Robert Koch
1843 - 1910
• A German scientist
• Formulated the
Bacteriological
techniques
• Staining Methods
• Discovered the
Mycobacterium and
Vibrio cholera
• Koch’s postulates- Causal
relationship between a
microorganism and a
specific disease

13. • Koch's postulates are the following:
• The microorganism must be found in abundance in all organisms
suffering from the disease, but should not be found in healthy
organisms.
• The microorganism must be isolated from a diseased organism and
grown in pure culture.
• The cultured microorganism should cause disease when introduced into
a healthy organism.
• The microorganism must be reisolated from the inoculated, diseased
experimental host and identified as being identical to the original specific
causative agent.

14. Waksman
• Professor of microbiology at Rutgers University.
• In 1952 was awarded the Nobel prize in physiology or medicine for
the part he played in the discovery of the antibiotic streptomycin,
which is produced by a soil bacterium.

15. Organisms included in the study
of Microbiology
1. Bacteria
2. Protozoans
3. Algae
4. Parasites
5. Yeasts and Molds
Fungi
6. Viruses
Bacteriology
Protozoology
Phycology
Parasitology
Mycology
Virology

16. Bacteria - what comes to mind?
• Diseases
• Infections
• Epidemics
• Food Spoilage
• Only 1% of all known bacteria cause human
diseases
• About 4% of all known bacteria cause plant
diseases
• 95% of known bacteria are non-pathogens

17. Microbes Benefit Humans
1.Bacteria are primary decomposers - recycle nutrients back into the
environment (sewage treatment plants)
2. Microbes produce various food products
• cheese, pickles, sauerkraut, green olives
• yogurt, soy sauce, vinegar, bread
• Beer, Wine, Alcohol

18. Microbes are also capable of
causing many diseases
Pneumonia Whooping Cough
Botulism Typhoid Fever Measles
Cholera Scarlet Fever Mumps
Syphilis Gonorrhea Herpes 1
Chlamydia Tuberculosis Herpes 2
Meningitis Tetanus RMSV
Strep Throat Lyme Disease AIDS
Black Plague Diarrhea Gangrene

19. Major Events
• 1546 Fracastoro suggests that invisible organisms cause disease.
• 1590–1608 Jansen develops first useful compound microscope.
• 1674 Leeuwenhoek discovers “animacules”.
• 1688 Redi refutes spontaneous generation of maggots.
• 1765–1776 Spallanzoni attacks spontaneous generation.
• 1786 Miller produces first classification of bacteria.
• 1798 Jenner introduces cowpox vaccination for smallpox.
• 1838–1839 Schwann and Schleiden propose the Cell Theory.
• 1835–1844 Bassi discovers silkworm disease caused by fungus.
• 1847–1850 Semmelweis introduces antiseptics to prevent disease.
• 1857 Pasteur describes fermentation.
• 1861 Pasteur disproves spontaneous generation.

20. • 1867 Lister publishes on antiseptic surgery.
• 1876–1877 Koch demonstrates anthrax caused by Bacillus anthracis.
• 1880 Laveran discovers Plasmodium, the cause of malaria.
• 1881 Koch cultures bacteria on gelatin; Pasteur develops anthrax vaccine.
• 1882 Koch discovers Mycobacterium tuberculosis.
• 1885 Pasteur develops rabies vaccine; Escherich discovers Escherichia coli.
• 1887 Richard Julius Petri develops petri dish (plate).
• 1887-1890 Winogradsky studies sulfur and nitrifying bacteria.
• 1889 Beijerinck isolates root nodule bacteria.
• 1890 Von Behring’s antitoxin for diptheria and tetanus
• 1894 Kitasato and Yersin discover Yersinia pesits.
• 1895 Bordet discovers complement.
• 1896 van Ermengem discovers Clostridium botulinum.
• 1899 Beijerinck proves virus causes tobacco mosaic disease.

21. • 1900 Reed proves yellow fever transmitted by mosquito.
• 1902 Landsteiner discovers blood groups.
• 1903 Wright and others discover antibodies.
• 1905 Schaudian and Hoffmann show Treponema pallidum causes syphilis.
• 1906 Wassermann develops complement fixation test for syphilis.
• 1910 Ricketts shows Rocky Mountain spotted fever caused by microbe.
• 1911 Rous discovers a virus can cause cancer.
• 1915-1917 D’Herelle and Twort discover bacterial viruses.
• 1921 Fleming discovers lysozyme.
• 1923 First edition of Bergey’s Manual.
• 1928 Griffith discovers bacterial transformation.
• 1929 Fleming discovers penicillin.
• 1931 Van Niel studies photosynthetic bacteria.

22. • 1933 Ruska develops electron microscope.
• 1935 Domagk discovers sulfa drugs.
• 1937 Chatton divides living organisms into prokaryotes and eukaryotes.
• 1941 Beadle and Tatum propose one-gene-one-enzyme theory.
• 1944 Waksman discovers streptomycin. (Nobel Prize in 1952)
• 1949 Enders, Weller, and Robbins grow poliovirus in human tissue culture.
• 1953 Watson and Crick propose DNA double helix.
• 1955 Jacob and Wollman discover F-factor plasmid.
• 1959 Yalow develops radioimmunoassay.
• 1961 Jacob and Monod propose lac operon.
• 1962 First quinolone synthesized.
• 1970 Arber and Smith discover restriction endonucleases.
• 1979 Insulin synthesized using recombinant DNA; smallpox officially declared
eradicated.
• 1977 Woese divides procaryotes into Bacteria and Archaea.

23. • 1980 Development of scanning tunnelling microscopes.
• 1982 Recombinant Hepatitis B vaccine developed.
• 1983-1984 HIV isolated and identified by Gallo and Montagnier; Mullis develops PCR
technique.
• 1986 First vaccine developed by genetic engineering approved for human use.
• 1990 First human gene therapy testing begun.
• 1992 First human trials of antisense therapy.
• 1995 Chicken pox vaccine approved for U.S. use; Haemophilus influenzae genome
sequenced.
• 1996 Methanococcus jannaschii and yeast genomes sequenced.
• 1997 Largest known bacterium, Thiomargarita namibiensis, discovered.
• 2000 Discovery that Vibrio cholerae has two chromosomes.
• 2001 Anthrax bioterrorism attack in New York, Washington D.C., and Florida.
• 2002 Infectious poliovirus synthesized from basic chemicals.
• 2003 SARS outbreak in China.
• 2005 “Super resistant” HIV strain isolated in New York City.

24. What is microbiology
Study of Micro-organisms: Organisms that EXIST as Single
Cells or cell clusters and must be viewed individually with the
aid of a Microscope
1. EXIST (Webster definition)To continue to be,
have life; live
HALLMARKS OF LIFE
1. METABOLISM (nutrient uptake, biomass, waste output)
2. DIFFERENTIATION (Bacillus spp. Caulobacter)
3. REPRODUCTION (binary fission)
4. COMMUNICATION (Pseudomonas aeruginosa)
5. EVOLUTION (antibiotic resistance, pathogens)

25. Metabolism
Take in nutrients from the environment
glucose, lactose, other sugars, fats=lipids, proteins,
toxic wastes, oils and petrol
Assimilate the nutrients into BIOMASS
DNA, proteins, carbohydrates and
complex carbohydrates, lipids
Release waste products into the environment
gases, alcohols, acids and organic compounds

26. Differentiation— to form distinct structures
Caulobacter spp. Vegetative cells versus stalk cells
K.C. Keiler M. Dworkin

27. Differentiation— to form distinct structures
Bacillus spp. endospore forming cells
Anabaena spp. Cyanobacteria forming heterocysts

28. Reproduction
To generate progeny of ones same type
A bacterium duplicates its DNA and forms daughter cells via binary fission
Yeast duplicates its DNA and forms a daughter cell via budding, or mates with
another yeast cell and produces haploid progeny.
J. Pitocchelli E. Hettema

29. Communication
interaction with
other cells—response to
other cells
Vibrio fischeri and Lantern
fish
Kolter and Losick
AMNH--NYC

30. www.med.umich.edu
Communication
bacteria communicate with
each other using a chemical
language called “Quorum
Sensing."

31. Phylogenetic classification of micro-organisms
Universal Ancestor
Algae
Fungi
Protozoa
Prokaryotic
Eubacteria Archaeabacteria
Eukaryotic

32. Prokaryotic and Eukaryotic Cells

33. Two Basic Cell Types:
Prokaryotic vs. Eukaryotic
Cells

34. TheDiscoveryof Cells
before
nucleus
true
nucleus

35. Two Basic Types
• Remember….cells are the basic unit of life for ALL living things.
• There are two basic types of cells:
1. Prokaryotic cells – found in bacteria
2. Eukaryotic cells – found in protists, fungi, plants and animals

36. Eukaryotic cells
Muscle cardiac cells
fibroblast
blood

37. Eukaryotic cell
Cytoplasm = cytosol + organelles

38. Eukaryotes
1. Has a nucleus with a nuclear envelope
2. Bigger and more complex than prokaryotes
3. Have membrane bound Organelles (golgi, ER,
lysosomes…etc)
4. DNA – double-stranded and forms chromosomes
(highly organized)
5. Can be uni- OR multicellular organisms
6. Ex: animals, plants, fungi

39. Eukaryotic Cells

40. Prokaryote Introduction
• Prokaryotes are much more diverse in both habitat and
metabolism than the eukaryotes.
• However, prokaryotes are not very diverse in body shape
or size.
• Nearly all prokaryotes are single-celled.
• Differentiation into different cell types almost never occurs
in prokaryotes.
• Two major groups: the Eubacteria (sometimes just called
Bacteria) and the Archaea (or Archaebacteria). Very
different genetically.

41. Prokaryote Cell Shapes
• Spheres (cocci), rods (bacilli), spirals (spirilla)

43. Prokaryotes
1. NO nucleus
2. NO membrane bound organelles (just ribosomes)
3. ALL are unicellular
4. Smaller than eukaryotic cells
5. Forerunner to eukaryotic cells (smaller and more simple)
6. DNA – single, circular double-stranded DNA (as genetic material)
7. Ex: ALL Bacteria

45. A Prokaryotic Cell

46. Flagella and Pili

47. Characteristics Shared
• Perform the same basic functions
• Surrounded by cell/plasma membrane to control what enters and leaves
the cell
• “Filled” with cytoplasm
• Contain ribosomes to make protein
• Contain DNA to give the general instructions for the cell’s life
• Contain all four biomolecules (lipids, carbs, proteins, and nucleic acids)
• Similar Metabolism
• Can be unicellular

48. Major Differences between prokaryotic and
eukaryotic micro-organisms
Prokaryotes
1. Non-membrane bound
nucleoid region
2. DNA-one circular molecule
one chromosome
3. Haploid-One copy of a gene
4. Plasma membrane does not
contain sterols
5. Reproduction—simple
binary
fission
6. Membrane bound organelles
are absent.
Eukaryotes
1. Membrane bound nucleus
containing DNA
2. DNA-linear molecules arranged
to form several chromosomes
3. Diploid-Two copies of a gene
4. Plasma membrane contains
sterols
5. Reproduction—meiosis and
mitosis
6. Presence of membrane bound
organelles such as chloroplasts
and mitochondria

50. What Makes Eukaryotic Cells Different?
• Much larger
• Much more complex
• Contain a true nucleus to house the genetic material (DNA)
• Linear DNA packaged into chromatin found inside the nucleus
• Contains specialized structures in the cytoplasm called organelles to
carry out various functions
• Not all have a cell wall

51. What Makes Prokaryotic Cells Different?
• Much smaller
• Less complex
• No true nucleus
• Circular DNA that is found in the cytoplasm
• No organelles found in the cytoplasm
• Surrounded by a cell wall

52. What does size have to do with it?
• Prokaryotic cells are much smaller than eukaryotic cells.
Why?
• Smaller surface area to volume allows nutrients to easily and quickly
reach inner parts of the cell.
• Eukaryotic cells are larger and can not pass nutrients as quickly. They
require specialized organelles to:
• carry out metabolism
• provide energy
• transport chemicals throughout the cell

53. Eukaryote VS. Prokaryote Picture