Ch 1 Textbook Flashcards
Content from the textbook that may be on quiz 1 (38 cards)
Microbiology is defined not only by the organisms it studies but also by what?
The tools used to study them
A distinct feature of microbiology is that microbiologists often remove microorganisms from their normal habitats and culture them isolated from other microbes; this is called a ____ or _____ culture.
pure or axenic culture
________ led to the discovery of microorganisms
Microscopy
The earliest microscopic observations of organisms appear to have been made between 1625 and 1630 on ____ and _____ by the Italian Francesco Stelluti (1577–1652), using a microscope probably supplied by Galileo (1564–1642).
bees and weevils
What is the importance of “Micrographia” by Robert Hooke (1665)?
It not only included detailed drawings of the fungus Mucor, but it also included important instructions on how to build microscopes.
Who was the first to document their sightings of bacteria and protists?
Antony van Leeuwenhoek, who likely used one of the prototypes in Micrographia, and could magnify 50-300x.
After the invention of the microscope, microbiology stagnated for 200 years until the creation of what?
Techniques for isolating and culturing microbes in
the laboratory
The creation of culture-based methods for studying microorganisms coincided with what?
Scientists grappling with the conflict over the
theory of spontaneous generation. This conflict and the subsequent studies on the role played by microorganisms in causing disease ultimately led to what is now called the golden age of microbiology.
Define spontaneous generation
The theory that living organisms could develop from nonliving matter
Who was the first to argue against spontaneous generation, and what experiment did he conduct to support his theory?
Francesco Redi (1626–1697), who carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. Using covered and uncovered containers of meat, Redi clearly demonstrated that the generation of maggots by decaying meat resulted from the presence of fly eggs, and meat did not spontaneously generate maggots, as previously believed.
What extracts were the forerunners of the culture media still used today in many microbiology laboratories?
Boiled hay and meat extracts
Many argued that the presence of organisms on boiled meat and hay extracts proved the theory of spontaneous generation; who disproved this and when?
John Needham (1713–1781) suggested that the organic matter in these extracts contained a vital force that could confer the properties of life on nonliving matter.
What was the role of Italian priest and naturalist Lazzaro Spallanzani (1729–1799) in microbiology?
Lazzaro Spallanzani (1729–1799) sealed glass flasks that contained water and seeds and then placed the flasks in boiling water for about 45 minutes. He found that no growth took place as long as the flasks remained sealed. He proposed that air carried germs to the culture medium but also commented that external air might be required for growth of animals already in the medium.
Felix Pouchet (1800–1872) claimed in 1859 to have carried out experiments conclusively proving that microbial growth could occur without air contamination, which provoked what scientist to finally settle the debate?
Louis Pasteur (1822–1895)
How did Louis Pasteur (1822–1895) settle the matter of spontaneous generation?
He first filtered air through cotton and found that objects resembling plant spores had been trapped. If a piece of the cotton was placed in sterile medium after air had been filtered through it, microbial growth occurred. Next he placed nutrient solutions in flasks, heated their necks in a flame, and drew them out into a variety of curves. The swan-neck flasks that he produced in this way had necks open to the atmosphere. Pasteur then boiled the solutions for a few minutes and allowed them to cool. No growth took place even though the contents of the flasks were exposed to the air. Pasteur pointed out that growth did not occur because dust and germs had been trapped on the walls of the curved necks. If the necks were broken, growth commenced immediately.
Pasteur had not only resolved the controversy by 1861 but also had shown how to keep solutions sterile.
Support for the germ theory of disease began when?
In the early 1800s
Give 3 examples of early scientists who helped prove germ theory
1) Agostino Bassi (1773–1856) demonstrated in
1835 that a silkworm disease was due to a fungal infection. He also suggested that many diseases were due to microbial infections.
2) In 1845 M. J. Berkeley (1803–1889) proved that the great potato blight of Ireland was caused by a water mold (then thought to be a fungus)
3) In 1853 Heinrich de Bary (1831–1888) showed that smut and rust fungi caused cereal crop diseases
What contributions of Pasteur also contributed to the ethanol and alcohol industries?
The discovery of yeast (helped the ethanol industry understand fermentation) and the development of pasteurization (helped the wine industry understand diseased wines)
Who developed a system of antiseptic surgery designed to prevent microorganisms from entering wounds?
English surgeon Joseph Lister (1827–1912). He heat sterilized instruments and used phenol on surgical dressings and at times sprayed it over the surgical
area
The first direct demonstration that bacteria cause disease came from the study of what and by whom?
The study of anthrax by the German physician Robert Koch (1843–1910)
Describe the development of Koch’s postulates
-Koch injected healthy mice with material from diseased animals, and the mice became ill. After
transferring anthrax by inoculation through a series of 20 mice, he incubated a piece of spleen containing the anthrax bacillus in beef serum. The bacteria grew, reproduced, and produced endospores. When isolated bacteria or their spores were injected into healthy mice, anthrax developed. -His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch’s postulates.
How did the creation of pure cultures come about?
Koch used gelatin, but bacteria didn’t grow well, so one of his student’s wives suggested agar as a nutrient/ medium, which is still used today. His laboratory also created Petri dishes as well as nutrient broth.
Who first theorized the existence of viruses, and what led him to theorize this?
Charles Chamberland (1851–1908), one of Pasteur’s associates, constructed a porcelain bacterial filter in 1884. Dimitri Ivanowski (1864–1920) and Martinus Beijerinck (1851–1931) used the filter to study tobacco mosaic disease. They found that plant extracts and sap from diseased plants were infectious, even after being filtered with Chamberland’s filter. Because the infectious agent passed through a filter that was designed to trap bacterial cells, they reasoned that the agent must be something smaller than a bacterium. Beijerinck proposed that the agent was a “filterable virus.”
Who was the first to perform an immunological study, and what was it?
Pasteur and Pierre Roux (1853–1933)
discovered that incubating the cultures for long intervals between transfers caused the cultures to lose their ability to cause disease. These cultures were said to be attenuated. When chickens were injected with attenuated cultures, they not only remained healthy but also were able to resist the disease when exposed to virulent cultures. Pasteur called the attenuated culture a vaccine in honor of Edward Jenner (1749–1823) because, many years earlier, Jenner had used material from cowpox lesions to protect people against smallpox
