Chapter 1• Microbiology is the study of microorganisms such as

• bacteria

• Archaea

• Viruses

• Fungi

• Protists

• Animals

• Decompose organic waste

• Are producers in the ecosystem by photosynthesis

• Produce industrial chemicals such as ethyl alcohol and acetone

• Produce drugs

Microorganisms:

Microorganisms:• Play a role in food/beverage production

• Are used to treat water

• Are used to clean up pollution

• Allows humans to

• Prevent food spoilage

• Prevent and treat disease occurrence

• Make drugs

Knowledge of microorganisms:

• Conduct research

• Etc.

• Knowledge of microorganisms led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories.

Microorganisms

bacteria fungus

protozoa algae virus

Naming and Classifying Microorganisms• Carolus Linnaeus established the system of

scientific nomenclature in 1735.

• Each organism has two names: the genus name and the species name.

• i.e. Staphylococcus aureus; Homo sapiens

• Scientific names:

• Are “Latinized” and used worldwide.

• May be descriptive or named after someone or something.

• After the first use, scientific names may be abbreviated with the first letter of the genus, and the species name:

• i.e. Staphylococcus aureus and Esherichia coli are found in/on the human body. On the skin you may find S. aureus, and E. coli lives in the large intestine.

Scientific names

• Prokaryotes

• Peptidoglycan cell walls

• Binary fission

• For energy, use organic chemicals, inorganic chemicals, or photosynthesis

• Vast majority do not cause human disease

Bacteria

• Prokaryotic

• Lack peptidoglycan

• Live in extreme environments

• Include:

• Methanogens

• Extreme halophiles

• Extreme thermophiles

• Not known to cause human disease

Archaea:

• Eukaryotes

• Use organic substances for energy

• Molds and mushrooms are multicellular

• Yeasts are unicellular

Fungi

• Eukaryotes

• Absorb or ingest organic substances

• May be motile via pseudopods, cilia, or flagella

Protozoa (Protists)

• Eukaryotes

• Use photosynthesis for energy

• Produce molecular oxygen and organic compounds

Algae (Protists)

• Non-cellular

• Consist of DNA or RNA core

• Core is surrounded by a protein coat called capsid

• Capsid may be enclosed in a lipid envelope

• Viruses are replicated only when they are in a living host cell

Viruses

Multicellular Animal Parasites

• Eukaryote

• Multicellular animals

• Parasitic flatworms and round worms are called helminths.

• Microscopic stages in life cycles.

Tapeworm

• Three domains

• Bacteria

• Archaea

• Eukarya

• Protists

• Fungi

• Plants

• Animals

Classification of Organisms

History of Microbiology• Microbes have been on earth for billions of

years

• In 1665, Robert Hooke was first to observe biological cells under a microscope (cork cells).

• The first live microbes were observed under a microscope in 1673 by Antoni van Leeuwenhoek.

• He observed microbes in teeth scrapings, rain water, etc.

van Leeuwenhoek’s microscope

• The hypothesis that living organisms arise from nonliving matter is called spontaneous generation.

• The Alternative hypothesis, that living organisms arise from preexisting life, is called biogenesis.

How is life created?

• 1668: Francisco Redi filled six jars with decaying meat.

Evidence against Spontaneous Generation

Conditions Results

3 jars covered with fine net No maggots

3 open jars Maggots appeared

From where did the maggots come?

• 1745: John Needham put boiled nutrient broth into covered flasks.

Evidence For Spontaneous Generation

Conditions Results

Nutrient broth heated, then placed in sealed flask

Microbial growth

From where did the microbes come?

• 1765: Lazzaro Spallanzani boiled nutrient solutions in flasks.

Evidence against Spontaneous Generation

Conditions Results

Nutrient broth placed in flask, heated, then sealed

No microbial growth

Final Evidence against Spontaneous Generation

• 1861: Louis Pasteur demonstrated that microorganisms are present in the air.

• Pasteur’s S-shaped flask kept microbes out but let air in.

The Golden Age of Microbiology• 1857-1914

• Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

• Pasteur showed that microbes are responsible for fermentation.

• Alcohol fermentation breaks down sugar to alcohol.

• We use this process to make beer and wine (yeast).

• Acetic acid fermentation breaks down alcohol to acetic acid.

• We use this process to make vinegar. Some bacteria can turn wine to vinegar.

Fermentation and Pasteurization

• Pasteur demonstrated that “spoilage” bacteria could be killed by heat.

• This application of high heat for a short time is called pasteurization.

Fermentation and Pasteurization

• The idea that some diseases are caused by microbes.

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

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

The Germ Theory of Disease

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

• 1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections.

• 1876: Robert Koch established a set of postulates, used to prove that a specific microbe causes a specific disease (i.e. anthrax).

The Germ Theory of Disease

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

• The term vaccination comes from vacca, latin for cow.

Vaccination

• Treatment with chemicals is chemotherapy.

• Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics.

• Antibiotics are chemicals produced by living organisms that inhibit growth of, or kill microbes.

• Synthetic drugs are laboratory-made.

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

The Birth of Modern Chemotherapy

• 1928: Alexander Fleming discovered the first antibiotic.

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

• 1940s: Penicillin was tested clinically and mass produced.

The Birth of Modern Chemotherapy

• Bacteriology is the study of bacteria.

• Mycology is the study of fungi.

• Parasitology is the study of protozoa and parasitic worms.

• Virology is the study of viruses.

• Immunology is the study of the immune system.

• Recombinant DNA technology: DNA from two or more different sources are combined.

Microbiology Related fields

Microbes are beneficial

• Nutrient recycling

• Bacteria recycle carbon, nitrogen, oxygen, sulfur, and phosphorus that can be used by plants and animals.

• Bioremediation

• Bacteria degrade organic matter in sewage.

• Bacteria degrade or detoxify pollutants such as oil and mercury

• Some microbes infect, and are pathogenic to, insects.

• Used to prevent insect attack on many crops.

• An alternative to chemical pesticides.

• Bacillus thuringiensis infections are fatal in many insects but harmless to other animals including humans and to plants.

• Application: sprayed or genetically engineered plants

Biological Insecticides

• Genetic engineering is a form of biotechnology.

• Through genetic engineering, bacteria and fungi can produce a variety of proteins including vaccines and enzymes.

• Missing or defective genes in human cells can be replaced in gene therapy by using viruses.

• Genetically modified bacteria are used to protect crops from insects and freezing.

Biotechnology and Genetic Engineering