history and scope

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