Post on 02-Jan-2016
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!