Unit 1The Science Of Microbiology

Donna HowellMedical MicrobiologyBlacksburg High School

What is Microbiology?

• Microbiology is defined as the study of the structure, function, uses, etc. of microscopic organisms.

• It is a specialized branch of Biology.

Why Microbes Matter

• Here’s how they affect our lives:– Cause disease

– Decompose dead organisms

– Help maintain balance of nature

– Capture energy from Sun for re-use

– Can be used to control other pests

– Used in genetic engineering

– Used to make food products

– Used to produce medicines

– Can be used to clean up oil spills

Microbes RULE!

The First Observations

• In 1665, Robert Hooke was the first to notice that life’s smallest living units were made up of cells, which was the beginning of the cell theory.

• In the late 1600’s, Antoni van Leeuwenhoek invented the first true microscope. He was the first to describe living microbes.

Spontaneous Generation

• Up until the 1800’s, scientists believed that life could arise spontaneously from nonliving matter.

Spontaneous Generation

• In 1668, Francisco Redi demonstrated that maggots did NOT arise spontaneously from meat. This was the beginning of the proof that spontaneous generation did not exist.

Spontaneous Generation

• In 1858, Rudolf Virchow challenged spontaneous generation with the concept of biogenesis, which says that living cells can ONLY arise from other living cells.

Spontaneous Generation

• In 1861, Louis Pasteur settled the issue. He proved that microbes can be destroyed by heat.

• This was the beginning of aseptic technique, which is the use of techniques that prevent contamination by unwanted microbes in laboratories and medical facilities.

• He is also credited with the development of the “germ theory of disease”, which says that microbes cause disease.

Golden Age of Microbiology

• Beginning in 1857 with Pasteur’s discovery of germ theory of disease, and for the next 60 years, many branches of microbiology were established and many new microorganisms were discovered.

• This was called “The Golden Age of Microbiology” due to the many discoveries!

Microbiology

The Golden Age of Microbiology

• During the “Golden Age”, many other discoveries were made:– Electron microscope invented –

could see viruses for the first time!

– Antibiotics were discovered

– More research money available after war was over

– Genes beginning to be studied

The Golden Age of Microbiology

• There were other accomplishments too:– In 1796, Edward Jenner was

the first to “vaccinate” people against smallpox.

– In late 1800’s, Pasteur discovered fermentation and pasteurization

– In the 1860’s, Joseph Lister began using aseptic technique to medical procedures

– In 1876, Robert Koch proved that bacteria caused disease (Koch’s Postulates)

Birth of Modern Chemotherapy

• Now that scientists knew microbes caused disease, they tried to find ways to cure disease.

• Treatment of disease by using chemical substances is called “chemotherapy”.

• In 1910, Paul Ehrlich came up with the first synthetic drug (not an antibiotic) used to treat syphilis.

• In 1928, Alexander Fleming discovered the first antibiotic, Penicillin

Modern Microbiology

• There are now many branches of microbiology due to specialization:– Bacteriology – study of bacteria– Mycology – study of fungi– Parasitology – study of protozoa

and parasitic worms– Virology – study of viruses– Immunology – study of the immune

system and how it responds to microorganisms

– Genomics – study of genes– Biotechnology – use of microbes in

practical ways

Introducing….Archaea!

• The first group of microbes we will study is the Archaea. These are the “ancient” bacteria – they have cell walls different than normal bacteria, and live in extreme environments:– Thermophiles – found in

HOT temperatures

– Psychrophiles – found in COLD temperatures

– Halophiles – found in SALTY habitats

– Acidophiles – found in ACIDIC habitats

Hot Springs

Deep Sea Hydrothermal Vent

Introducing….Bacteria!

• Found everywhere – literally!

• Can be autotrophic or heterotrophic.

• Can live with or without oxygen.

• Can be beneficial or harmful.

• Most numerous organisms on Earth.

Introducing….Viruses!

• Made of a core of nucleic acid and a protein coat.

• Cannot survive on own – need a host cell.

• Can infect ANY type of cell, not just human.

• Smallest of all microbes.

• Two subgroups:– Viroids – only contain

nucleic acid

– Prions – only contain protein coat

Introducing….Protozoa!

• A type of Protist that is medically significant – very diverse group.

• Includes 4 subgroups:– Ciliates – move with

cilia, or hairs

– Flagellates – have flagella for movement

– Sarcodines – move with pseudopods, or false feet

– Apicomplexans – do not move; need a host animal

GiardiaTrypanosoma

Plasmodium

Introducing….Algae!

• Plant-like microorganisms, can undergo photosynthesis.

• Produce 75% or more of planet’s oxygen

• Important to the food chain

• Types:– Green algae – most like plants;

found in water

– Diatoms – hard shell; found in ocean

– Dinoflagellates – found in ocean; can glow. Cause of red tide.

Cyanobacteria

Diatoms

Dinoflagellates

Introducing….Fungi!

• Can be single-celled to multi-cellular

• Decomposers of organic matter

• Have cell walls of chitin

• Heterotrophic; absorb food

• Cannot undergo photosynthesis

• Examples: mushrooms, slime molds, water molds

Yeast Cells

Introducing….Helminths!

• Also known as parasitic worms.

• Multicellular, eukaryotic animals

• Must have host(s) to reproduce.

• Examples: hookworm, pinworms, etc.

Hookworm

Ascaris

Introducing….Parasitic Insects!

• Insects that are human parasites are also included in the field of microbiology.

• Examples are scabies, crabs, head lice, and some others.

The End!