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Muse’s Micro

Website http://www-personal.umich.edu/~muse/Biol243.html

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SCOPE AND HISTORY OF MICROBIOLOGY

CHAPTER 1

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Why Study Microbiology?

Ubiquity

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Microbes in Our Lives

Microorganisms are organisms that are too small to be seen with the unaided eye.

“Germ” refers to a rapidly growing cell.

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Why Study Microbiology?

Biological roles- decomposers, recyclers, symbionts

Animal digestion - ruminants, methane

Food Microbiology - yogurt, sauerkraut, Kim Chee, cheese, beer, bread etc.

Food safety - prevent putrefication, disease etc.

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Why Study Microbiology? Pharmaceuticals- produce complex drug

molecules. (ex. insulin )

Bioremediation - using microbes to clean pollution

Pathogenicity - bacteria and viruses that make us sick

Fundamental Biology most biochemical pathways worked out with microbes

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Microbes in Research

Simple structure- many are prokaryotic

Large populations - up to billions/ml

Rapid growth rates Vibrio harveyii = fastest grower known 1 gen/15 mins

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Scale of Microbes

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Three domains– Bacteria– Archaea– Eukarya

• Protists• Fungi• Plants• Animals

Classification of Microorganisms

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Microbe Types Bacteria

prokaryotes

EubacteriaArchaebacteria

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Prokaryotes Peptidoglycan

cell walls Binary fission For energy, use

organic chemicals, inorganic chemicals, or photosynthesis

Bacteria

Figure 1.1a

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Prokaryotic Lack peptidoglycan Live in extreme

environments Include:

– Methanogens– Extreme halophiles– Extreme thermophiles

Archaea:

Figure 4.5b

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Microbe Types

Algae

Fungi

Protista, Planta

Eukaryotes

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Eukaryotes Cellulose cell walls Use photosynthesis

for energy Produce molecular

oxygen and organic compounds

Algae

Figure 1.1d

Volvox

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Eukaryotes Chitin cell walls Use organic chemicals

for energy Molds and mushrooms

are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae

Yeasts are unicellular

Fungi

Figure 1.1b

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Microbe Types

Viruses

Living?

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Microbe Types

Protozoa

eukaryotes

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Eukaryotes Absorb or ingest

organic chemicals May be motile via

pseudopods, cilia, or flagella

Protozoa

Figure 1.1c

Amoeba

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Microbe Types

Helminths/Arthropods

Eukaryotes (multicellular)

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Eukaryote Multicellular

animals Parasitic

flatworms and round worms are called helminths.

Microscopic stages in life cycles.

Multicellular Animal Parasites

Figure 12.28

tapeworm

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Microorganisms:

Figure 1.1

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Roles of Microbiologists

Biological

Pharmaceutical/Vaccines

Agricultural- Rumen microbiology

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Microbiology Settings

Universities

Commercial laboratories

food prep & cosmetics

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Microbiology Settings

Legal

Clinical

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Microbiology Settings

Public Health Epidemiology

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Microbiology History

Plagues in History

http://www.oddee.com/item_90608.aspx

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The Black Plaque-Bubonic plaque

1348 and 1350

Yersinia pestis

Flea vector.

(1340 - 1771)

Killed 75 million people worldwide

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Smallpox (430 BC? - 1979):Killed more than 300 million people worldwide in the 20th century alone, and most of the native inhabitants of the Americas. Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30–35%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims. Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors.

Smallpox killed an estimated 60 million Europeans, including five reigning European monarchs, in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors became blind.

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Microbiology History

Early Studies– Hooke Cork Slices- 1st Scope (cell)

– Van Leeuwenhoek microscope

– Linnaeus classification

– Schwann cell theory

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Fig. 1-9

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Fig. 1-10

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Germ Theory vs. Spontaneous Generation

Redi - maggots http://en.wikipedia.org/wiki/Francesco_Redi

Spallanzani - boiling http://en.wikipedia.org/wiki/Lazzaro_Spallanzani

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Germ Theory vs. Spontaneous Generation

Pasteur

http://en.wikipedia.org/wiki/Louis_Pasteur

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Understanding Disease

Robert Koch Koch’s

postulates

Lister/

Semmelweiss

handwashing

disinfection

http://en.wikipedia.org/wiki/Robert_Koch

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Koch’s postulates

1. The suspected causal organism must be constantly associated with the disease.

2. The suspected causal organism must be isolated from an infected plant (or animals)and grown in pure culture.

3. When a healthy susceptible host is inoculated with the pathogen from pure culture, symptoms of the original disease must develop.

4. The same pathogen must be re-isolated from plants (animals) infected under experimental conditions.

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Special Fields of Study Immunology

Virology

Immune system and it’s interaction with microbes

Study of very small ?living? Viral particles

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Special Fields of Study

Chemotherapy– Antibiotics

– Synthetics

Alexander Fleming Penicillin

Natural products

Man-made

penicillin

doxycycline

Erhlich

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Special fields of Study

Genetics/Molecular Biology genes and how they are expressed

Recombinant DNA technology– Genomics decyphering genomes and expression

– Proteomics decyphering protein structure/function

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Microbes I know and Love?

Bacillus megaterium Klebsiella aerogenes Escherichia coli Klebsiella pneumoniae Mycobacterium smegmatis Mycobacterium marinum

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A Brief History of Microbiology

Ancestors of bacteria were the first life on Earth.

The first microbes were observed in 1673.

http://en.wikipedia.org/wiki/Antonie_van_Leeuwenhoek

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In 1665, Robert Hooke reported that living things were composed of little boxes or cells.

In 1858, Rudolf Virchow said cells arise from preexisting cells.

Cell Theory. All living things are composed of cells and come from preexisting cells

The First Observations

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The Golden Age of Microbiology

1857-1914 Beginning with Pasteur’s work,

discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

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Pasteur showed that microbes are responsible for fermentation.

Fermentation is the conversation of sugar to alcohol to make beer and wine.

Microbial growth is also responsible for spoilage of food.

Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid).

Fermentation and Pasteurization

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Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization.

Fermentation and Pasteurization

Figure 1.4

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1835: Agostino Bassi showed a silkworm disease was caused by a fungus.

1865: Pasteur believed that another silkworm disease was caused by a protozoan.

1840s: Ignaz Semmelweiss advocated handwashing to prevent transmission of puerperal fever from one OB patient to another.

The Germ Theory of Disease

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1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases.

1876: Robert Koch provided proof that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, used to prove that a specific microbe causes a specific disease.

The Germ Theory of Disease

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1796: Edward Jenner inoculated a person with cowpox virus. The person was then protected from smallpox.

Called vaccination from vacca for cow The protection is called immunity

Vaccination

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Treatment with chemicals is chemotherapy. Chemotherapeutic agents used to treat

infectious disease can be synthetic drugs or antibiotics.

Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes.

Quinine from tree bark was long used to treat malaria.

1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis.

1930s: Sulfonamides were synthesized.

The Birth of Modern Chemotherapy

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1928: Alexander Fleming discovered the first antibiotic.

He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus.

1940s: Penicillin was tested clinically and mass produced.

The Birth of Modern Chemotherapy

Figure 1.5

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Bacteriology is the study of bacteria. Mycology is the study of fungi. Parasitology is the study of protozoa and

parasitic worms. Recent advances in genomics, the study of an

organism’s genes, have provided new tools for classifying microorganisms.

Modern Developments in Microbiology

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Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases.

The use of immunology to identify some bacteria according to serotypes (variants within a species) was proposed by Rebecca Lancefield in 1933.

Modern Developments in Microbiology

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Virology is the study of viruses. Recombinant DNA is DNA made from two

different sources. In the 1960s, Paul Berg inserted animal DNA into bacterial DNA and the bacteria produced an animal protein.

Recombinant DNA technology or genetic engineering involves microbial genetics and molecular biology.

Modern Developments in Microbiology

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Using microbes– George Beadle and Edward Tatum showed that

genes encode a cell’s enzymes (1942)– Oswald Avery, Colin MacLeod, and Maclyn McCarty

showed that DNA was the hereditary material (1944).– Francois Jacob and Jacques Monod discovered the

role of mRNA in protein synthesis (1961).

Modern Developments in Microbiology

54* The first Nobel Prize in Physiology or Medicine.

Selected Novel Prizes in Physiology or Medicine

1901* von Behring Diphtheria antitoxin

1902 Ross Malaria transmission

1905 Koch TB bacterium

1908 Metchnikoff Phagocytes

1945 Fleming, Chain, Florey Penicillin

1952 Waksman Streptomycin

1969 Delbrück, Hershey, Luria Viral replication

1987 Tonegawa Antibody genetics

1997 Prusiner Prions