Some first questions about science....
Hippocrates (ca. 460-ca. 377 b.c.) wondered if there was a link between environment and disease
Thucydides (ca. 460-ca. 404 b.c.) questioned why he & other survivors of the plague could have intimate contact with victims and not fall ill again
Antoni van Leeuwenhoek (1673)
Dutch tailor, developed simple microscopes to inspect cloth.
Discovered microorganisms; "wee animalcules," or "beasties," now called microbes
Discovered protozoa in 1674
Discovered bacteria in 1676
Father of Microbiology
Spontaneous generation
(abiogenesis);
living organisms can arise from nonliving matter
Ex: Moist soil toads, snakes, mice
Biogenesis:
living organisms can arise only from preexisting living organisms
Francesco Redi
set up an experiment to disprove spontaneous generation of maggots. Filled 2 jars with decaying meat, sealed one and left the other open (only the open jar developed maggots). Another experiment was set up in which a jar was covered with a fine mesh inste
John Needham
seemed to help prove the case for spontaneous generation by heating nutrient broth and pouring it into covered flasks (developed microbial growth) he claimed that the "vital force" had been destroyed by the heating
Lazzaro Spallanzani
he showed that broth that was heated after being put into a sealed flask did not develop microbial growth.
Louis Pasteur
1)Microorganisms can be present in nonliving matter (even in air). 2)Spontaneous generation disproved. 3)Heat can destroy microbes
who discovered Aseptic Techniques?
Pasteur. Used to prevent the contamination by unwanted microorganisms
Water purification, sewage collection and treatment
Romans developed sophisticated drinking water and sewer systems (even indoor plumbing), but these ideas were lost during the Dark Ages.Most villages, towns, and cities had problems with certain diseases due to fecal contamination of their drinking water b
Bassi (1830s-40s)
Perhaps the first to demonstrate a microbial cause of disease. Showed that a microscopic fungus causes a disease in silkworms. Suggested that human diseases could be caused by microbes also
Semmelweiss (1840s)
Suspected doctors/midwives were transmitting childbed fever to women during childbirth 2. Required hand washing in a chloride of lime solution. Incidence of childbed fever dropped from up to 50% to 1-3% Viciously criticized Died in exile and shame
Joseph Lister (1860s)
1. Used a disinfectant (phenol) to clean wounds, surgical dressings and instruments 2. Large decrease in wound infections 3. Concept of Asepsis (lack of germs) finally accepted
Koch (1876)
Developed pure culture techniques for growing bacteria in the lab. 2. Proved Germ Theory of Disease by showing that a specific type of bacteria causes anthrax 3. Koch's Postulates: Steps for determining the cause of any infectious disease.
Smallpox inoculation by Chinese physicians
Used intranasal inoculation of individuals with dried small pox pustules from patients with mild cases Records seem to indicate the practice started as early as the 6th century in China Became widely used in China in the 16th and 17th centuries In the 17t
Jenner (1796)
Milkmaids who had had cowpox seemed to be protected from smallpox Showed that inoculation with material from cowpox lesions leads to immunity from smallpox (1st vaccine) 3. Steady decline in smallpox cases until eradicated in 1977
Louis Pasteur
1. Found that certain microbes that lost their ability to cause disease due to repeated culturing in the lab could be used to generate immunity Anthrax, cholera, rabies vaccines
Fleming (1928
Discovered fungi produced penicillin which killed bacteria
Chain and Florey (1941)
Showed penicillin was effective against bacterial infections in patients 1 Commercial production of penicillin - Just in time for WWII
1970s-1990s
Most drug companies stop or greatly reduce antibiotic research
Today
Major problem with antibiotic resistant bacteria, few new antibiotics
Genetics and Molecular Biology (Avery, Macleod, and McCarty)
showed that DNA was the molecule encoding heredity
Watson and Crick
discovered the structure of DNA
Mullis
developed the polymerase chain reaction (PCR)
Early Years of Microbiology
van Leeuwenhoek started asking "What does it really look like?"
he built the first microscope
discovered protozoa in 1674
discovered bacteria in 1676
Linnaeus asked "How can microbes be Classified?"
created the taxonomic system
archaea - prokaryote
bacter
Golden Age of Microbiology
Is Spontaneous Generation of Microbial Life Possible?"
"What Causes Fermentation?"
"What Causes Disease?"
"How Can We Prevent Infection and Disease?
Scientists who sparked the question, "Is Spontaneous Generation Possible?
Francesco Redi asked, "Is Spontaneous Generation possible?" by experimenting with meat, leaving it in containers, away from flies
Pasteur finally disproved spontaneous generation by using swan-neck flasks
Scientists who asked the question, "What causes fermentation?
Louis Pasteur questioned (in 1857), "What Causes Fermentation?" by created Pasteurization (use of heat to kill pathogens); figured out that bacteria spoiled wine
Eduard Buchner (in 1897) demonstrated that enzymes, promote chemical reactions, like fermenta
Scientists who asked the questions, "What Causes Disease?
Louis Pasteur asked "What Causes Disease?" and figured out that bacteria caused wine to spoil and microorganisms caused diseases (infectious diseases); now known as germ theory of disease
Robert Koch studied the cause of anthrax & created Koch's Postulate
Germ theory of disease
Pasteur's theory that microorganisms cause (infectious) disease
Pathogens
microorganisms that causes SPECIFIC diseases
Koch's Postulates
Series of steps that must be used to prove the cause of any infectious disease:
Identify the agent (must be in every disease case; absent from every healthy case)
Isolate the agent & grow it outside the host
Introduce it into a healthy host (host must get
Robert Koch
studied anthrax to determine its cause for disease;
created Koch's postulates (4 steps);
developed isolation techniques, stain cells, estimate population size, sterlize growth media, and transfer bacteria between media
Scientists who asked, "How Can we Prevent Infectious and Disease?
Ignaz Semmelweis (in 1848) - use of chlorinated lime water; reduce deaths during birth
Joseph Lister - created antiseptic methods with phenols
Florence Nightingale - nutrition and antiseptic standards helped wounded soldiers to survive
John Snow - mapped
Ignaz Semmelweis
Viennese physician; required medical students to wash with chlorinated lime water to decrease "cadaver particles" & reduce mortality rates during birth; (circa 1848)
Modern Age of Microbiology
What are the Basic Chemical Reactions of Life?"
"How do Genes Work?"
"What Roles do Microorganisms Play in the Environment?"
"How Do we Defend Against Disease?"
"What Will the Future Hold?
What Will the Future Hold?
What prevents certain life forms from being grown in the lab?
How can we reduce the threat of new and re-emerging infectious diseases?
What can we do at a genetic level to defend against pathogenic microbes?
Can microbes be used in ultraminiature technolo
Describe Protozoans
1. single-celled
2. eukaryotes
3. similar to animals in their nutritional needs and cellular structure.
4. Most are capable of locomotion (categorized by pseudopodia, cilia, flagella)
5. Some protozoa, such as the malaria-causing Plasmodium , are nonmotil
General Characteristics of Fungi
1. Eukaryotic;
2. are different from plants because they obtain their food from other organisms (rather than making it by photosynthesis).
3. They differ from animals by having cell walls.
4. Microscopic fungi include some molds and yeasts.
mold ex - cott
General characteristics of Viruses
...
Redi's experiments disproving Spontaneous Generation
1. unsealed flask, maggots covered the meat w/in days.
2. sealed flask, kept away flies; no maggots
3.. flask with gauze; kept away flies; no maggots on meat; maggots on gauze.
Scientific Method
1. observations lead a scientist to ask a question about some phenomenon.
2. generate a hypothesis�a potential answer to the question.
3. design and conduct an experiment to test the hypothesis.
4. accept, reject, or modify the hypothesis; based on result
Scientists who asked "What are the Basic Chemical Reactions of Life?
Pasteur (fermentation) and Buchner (enzymes)
Microbial genetics
study of inheritance in microorganisms
Biochemistry
study of metabolism
Molecular biology
uses biochemistry, cell biology, and genetics to explain cell function at the molecular level
Genetic engineering
involves manipulation of genes for practical applications, (ex. pest-resistant crops & treatment of disease
Gene therapy
use of recombinant DNA to repair defective genes
Environmental microbiology
studies the role of microorganisms in their natural environment
Recombinant DNA
DNA composed of genes from more than one organism
Serology
study of blood serum