arose, each being pure isolates from the animal Koch was able to test/isolate the cause of anthrax However potato medium not good, another scientist used gelatin (still not good, would melt in summertime) led to development of agar : Few microbes are able to degrade agar and it melts at 100 degrees C, remains molten at temperatures above 45 degrees C allows the mixing of the agar with heat-sensitive nutrients and microbes After solidification, it does not melt until temp of 100 degrees C is again attained, facilitating the easy cultivation of pathogens Can also be stored for long periods of time, allowing cultivation of slow-growing microbes Any type of broth can be mixed w agar, giving great flexibility in different mediums Koch also developed methods of pure culture maintenance and aseptic technique - manipulation of pure cultures in a manner that prevents their contamination by outside microorganisms, prevents spread of septic things to environment Another problem in Koch’s lab was solved by Julius Petri: developed shallow glass dishes with one having slightly larger diameter than the other as a cover petri plate Key Takeaways 1. Science is interdependent and new discoveries depend upon earlier contributions from many other scientists. 2. Microbes were first seriously described in the 17th century by Robert Hooke and Anton van Leeuwenhoek using simple microscopes. 3. Ferdinand Cohn continued this work many years later, making a first systematic attempt at classifying them. 4. Robert Koch developed techniques for handling microbes and many of these methods for cultivating microbes are still used today. Chapter 1-5: Spontaneous generation Disproven! Spontaneous generation: hypothesis that some vital force contained in or given to organic matter can create living organisms from inanimate objects Louis Pasteur- air can contaminate material by spreading microbes, Tyndall showed the existence of heat-resistant spores in the materials Key Takeaways 1. For many centuries many people believed in the concept of spontaneous generation, the creation of life from organic matter.
2. Francesco Redi disproved spontaneous generation for large organisms by showing that maggots arose from meat only when flies laid eggs in the meat. 3. Spontaneous generation for small organisms again gained favor when John Needham showed that if a broth was boiled (presumed to kill all life) and then allowed to sit in the open air, it became cloudy. 4. Louis Pasteur ended the debate with his famous swan-neck flask experiment, which allowed air to contact the broth. Microbes present in the dust were not able to navigate the tortuous bends in the neck of the flask. Chapter 1-6: Microbes are discovered to cause disease Ignaz Semmelweis- Hungarian physician working in Vienna realized that asepsis in obstetrical wards could prevent the transmission of childbirth fever from patient to patient o Started a policy for all attending physicians to wash their hands with chloride of
- Spring '08