Undestanding The History Of Microbiology Flashcards
What is a microbe?
a living organism that requires a microscope to be seen
- generate the air we breathe (nitrogen gas, oxygen, and carbon dioxide)
-make essential vitamins (ie. B12)
-primary producer of the food webs
involved in food production
- some are pathogens
What are the four types of microbes?
Bacteria, Viruses, Fungi, Protozoa
What are the two types of cellular organization?
Prokaryotic - (bacteria, archaea) cell lacks a membrane - enclosed nucleus
Eukaryotic - (Plant, animal, fungi, protozoa) cells contain a membrane - bound nucleus
Viruses - non cellular microbes that must infect a host cell to reproduce
Microbes impact human culture 1
10,000 BCE - food and drinks are produced by microbial fermentation – Egyptians, Chinese, and others
Microbes impact human culture 2
15,000 BCE - tuberculosis, polio, leprosy, and smallpox are evident in mummies and tomb art – Egyptains
Microbes impact human culture 3
50 BCE - Copper is recovered from mine water and acidified by sulfur oxidizing bacteria – Roman metal workers under Julius Caesar
Microbes impact human culture 4
1,000 CE - smallpox immunization is accomplished by transfer of secreted material – Chinese and Africans
Microbes impact human culture 5
1,025 CE - Diseases are observed to be contagious. The basis of hygiene and quarantine is proposed – Avicenna, or Ibn Sina (Persia)
Microbes impact human culture 6
1,300-1,400 CE - The Black Death (bubonic plague) killed 17 million people in Europe and Asia – Catherine of Siena nursed plague victims; canonized as patron saint of nurses
Microbes impact human culture 7
!,546 CE - Syphilis and other diseases are observed tp be contagious – Girolamo Fracastoreo (Padua)
Microbial Diseases Devastate Human Population
- smallpox, tuberculosis, leprosy, bubonic plague, HIV/AIDS
- The overwhelming majority of microbes humans interact with are beneficial pr neutral
- Humans are inhabited by 10x as many bacterial cells as human cells
- Less than 1% of known bacteria causes severe and life threatening illness in humans
- History has focused on the 1% because of their impact on human life
Catherine of Siena (1347-1380)
Patron Saint of Nursing - cared for the ill and buried the dead
Early Microscopy and the Origin of Microbes dates
1676 - microbes are observed under a microscope by Antonie van Leeuwenhoek (Netherlands)
1717 - Smallpox is prevented by inoculation of pox material, a rudimentary form of immunization – African and Asia; Turkish women taught Lady Montagu who brought the practice to England
1765 - Microbes fail to grow after boiling in a sealed flask: evidence against spontaneous generation – Lazzaro Spallanzani (Padua)
1798 - Cowpox vaccination prevents smallpox – Edward Jenner (England)
1835 - Fungus causes disease in silkworms (first pathogen to be demonstrated in animals) – Agostino Bassi De Lodi (Italy)
1847 - Chlorine as antiseptic wash for doctors hands decreases pathogens – Ignaz Semmelweis (Hungary)
1881 - Bacterial spores survive boiling but are killed by cyclic boiling and cooling – John Tyndall (Ireland)
Robert Hooke
First to publish in Micrographia (1665) his work using microscope (mites, mold, small worms)
- First to observe living material and call them cells
Antoni Van Leeuwenhoek (Dutch)
First to observe and record bacteria and protozoa
- Began making and using single lens microscopes
- Often made new microscope for each specimen
-Examined water and visualized tiny animals, fungi, bacteria, algae, and single celled protozoa or small animals “animalcules” (1674)
- It took nearly 200 years before a connection was made between microbes and human diseases
Is Spontaneous Generation of Microbes possible?
Some thought living things arose from three processes
- asexual reproduction
- sexual reproduction
-nonliving matter
Aristotle
proposed spontaneous generation - living things can arise from non living matter
Experimentation - Spontaneous Generation
Redi’s experiments
- When decaying meat was kept isolated from files, maggots never developed
- Meat exposed to files was soon infested
- As a result, scientist began to doubt Aristotle’s theory
Needham’s Experiments - Spontaneous Generation
Broth (gravy) is boiled in flask
- One flask is left open
- One flask is sealed with corks
- Both flasks were cloudy (turbid)
- Scientist thought microbes, but not animals, could arise spontaneously
- Needham’s experiments reinforced this idea
- Vials were cloudy due to a “life force”
Spallanzani’s Experiments - Spontaneous Generation
- Both (gravy) is boiled in flask for an hour
- One flask is left open
- One flask is completely sealed
- Flask did not become cloudy unless seal was broken
Pastur’s Experiments - Spontaneous Generation
When the “swan-necked” flask remained upright, no microbial growth appeared
- When the flask was titled, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day
The Scientific Method
- Spontanoue generation debate led in part to scientic method
- Observation leads to question
- Question generates hypothesis
- Hypothesis is tested through experiment(s)
- Results prove or disprove hypothesis — accepted hypothesis leads to theory/law - Reject or modify hypothesis
What causes Fermentation?
• spoiled wine threatened livelihood of vintners
• some believed air caused fermentation; others insisted living organisms caused fermentation
• vintners funded research of methods to promote
production of alcohol and prevent spoilage during fermentation
• this debate also linked to debate over spontaneous
generation
What causes Disease?
Divine Origin of Disease
- A lor of the early historry of microbiolgy was under the unfleunce of scoial and theological beliefs of the times
- Among ancient people, epidemics of disease were thought to be supernatural in origin , sent bt the Gods as punishment for the sins of man. Treatment and prevention were by sacrifices to appease the anger of the gods
- Gradually the Divine Origin of Disease was rejected, as the belief in “living agents” as the case of the disease grew slowly. Some refer to this belief in living agents as the “Germ Theory of Disease”
What causes Disease?
- Francastoro wrote a book called : Contagion, Contagious Disease and Treatment
- This book stated the theory that living agents, “contagium vivum” caused disease and that the disease was transmitted by – Direct Contact , Fomites, Air
- Before 1850, theories on the cause of diseases affecting humans did not include microbes.
Etiology
Study of the Causation of Disease
Louis Pasteur
Developed Germ Theory of Disease
- Microorganism (“germs”) are responsible for disease
Robert Koch
Studied causative agents of disease
- Anthrax
- Examined colonies of microorganisms
Koch’s Contributions
Simple staining techniques
-First photomicrograph of bacteria
-First photomicrograph of bacteria in diseased tissue
-Techniques for estimating CFU/ml
-Use of steam to sterilize media
-Use of Petri dishes and gelatin in broth (nutrient agar plates)
-Techniques to transfer bacteria
-Bacteria as distinct species
Koch’s postulates became standards for linking a specific organisms to a specific disease
list his postulates in order
1. The microbe is found in all cases of the disease but is absent from healthy individual’s
2. The microbe is isolated from the diseased host and growth in the pure culture
3. When the microbe is introduced into a healthy, susceptible host, the same disease occurs
4. The same strain of microbe is obtained from the newly diseased host
What did Pasteurs lab focus on?
Infection and immunity
- anthrax and cholera temperature sensitivity leads to principles of vaccination
- Pasteur developed a successful rabies vaccine
What did Koch’s lab focus on?
Isolation, culture, and identification
- Isolation of tubercle, typhoid, and diphtheria bacilli
- Koch isolated the tubercle bacillus and determines that water is the key to tuberculosis transmission
Discovery of viruses
Early germ hunters noted that some contagious diseases could pass through filters and therefore could not be bacterial cells
- “Infective particles” causing a disease in tobacco plants were crystallized by Wendell Stanley and called “tobacco mosaic virus” (TMV)
- Viruses are non cellular agents of disease
Epidemiology
The study of the source, cause, and mode of transmission of disease
Ignaz Semmelweis
Determines the source of blood poisoning (puerperal/sepsis/childbed fever) of women in children. Hand washing with chlorinated lime water (hygiene)
Joseph Lister
Developed the practice of antisepsis, chemical disinfection of external living surfaces. He sprayed carbolic acid on surgical wounds to prevent infection
Florence Nightingale
Introduced cleanliness and other antiseptic techniques in nursing and involved in nursing education and demonstrated the mortality due to diseases
John Snow
Determined the cause of cholera transmission in London was a water well pump in the town
How can we prevent infection
•By 1000 BCE in India and China, exposing a person to fluids from a pox pustule was being used to prevent deaths from smallpox.
•Variolation involved exposing individuals to dried smallpox (Variola) specimens
•Dr. Edward Jenner developed vaccination for smallpox, inoculating individuals with cowpox (instead of smallpox).
•In the 18th century, Lady Mary Wortley Montagu, pox survivor and wife of the British Ambassador, brought the practice to England.
What did Louis Pasteur show?
Showed that exposure to attenuated (weakened) strains of bacteria conferred immunity to a disease without causing severe symptoms
How do we defend against disease
- Immune system
- antimicrobial agents
- •In 1910, Paul Erlich developed Salvarsan, a chemical that cured individuals of syphilis
•In 1929, Alexander Fleming observed that a species of Penicillium
mold killed bacterial cells, leading to the development of penicillin
•Chemists Florey and Chain purified the chemical the mold produced and successfully treated patients who were dying of bacterial infections.
•Mass production of penicillin gave birth to the pharmaceutical industry.
•Domagk (1935) discovered Sulfa drugs
What does CDC stand for?
Centers for Disease Control and Prevention
What does WHO stand for
World Health Organization
List the Microbiological Investigations
Environmental Science
•Immunology
•Epidemiology
•Chemotherapy
•Genetic Engineering
•Biochemistry
How do genes work?
Microbial genetics
•Molecular biology
•Recombinant DNA
technology
•Gene therapy
-Discovery of the structure and function of DNA in the 1950s transformed the fields of medicine and biotechnology
•DNA sequencing method, which revealed the nucleotide sequences of a virus, was developed by Frederick Sanger in 1977.
•DNA sequencing of the genome of a cellular organism sequence (H. influenzae) was completed in 1995.
•DNA sequencing of the human genome (Human Genome Project) was completed in 2003.
•DNA sequencing of the genomes of human bacterial symbionts in the Human Microbiome Project is ongoing.
Infection disease kills how many people globally each year?
15 million
Can a pathogen cause more than one disease?
•A pathogen can cause more than one disease, and a disease can be caused by more than one microbe
Pathogen facts
Pathogens are becoming resistant to antimicrobials
•Pathogens can be used intentionally to infect large numbers of people through bioterrorism
•New diseases are emerging, and old diseases are reemerging
