Lesson 4 (22/9/14)

Date : 22/9/14

Topic : Brief History of Microbiology

Activities
1. Thank a microbe (Deadline : 18/10/14)
- application decided by own
-environment, industry, food, agriculture, medical

2. E-portfolio

3. Adopt a microbe - scrapbook (Deadline : 9/12/14)
- 7/10/14 determine name of microbe

Notes

Species of microbes
-

Terms in microbiology

• Spontaneous generation (life arises spontaneously from non-living matter)
• Biogenesis (living cells can arise only from preexisting living cells)
• Germ theory of disease (some diseases are caused and spread between people by microorganisms)


• Koch's postulates (the framework to study etiology of any infectious disease)
• 
• Exceptions
• Not all microbes can be cultured in artificial media (e.g. some need other means such as tissue cells)
• Similar symptoms could elicit by different species of microbes.
• Some pathogens can cause several disease conditions.
• Pasteurization (heat milk to high temperature then swiftly cooling and bottling it ; just kill most pathogens ; originally used to prevent wine and beer from souring)
• Sterilization (kill all microorganisms in the food)
• UHT - Ultra-high temperature pasteurization (sterilize food by heating it above 135°C  for 1 to 2 seconds to kill spores)
• Hydrothermal vents
• Animalcules (a single cell, looking for moving bacteria)

My own exploration

• Francesco Redi carried out experiments too and produced compelling evidence against the theory of spontaneous generation (by using meat, meat covered with paper, meat covered with cheesecloth)
• John Tyndall proved the existence of heat-resistant spores in many materials. Boiling does not kill these spores, so it is possible to be present in the chicken broth of Needham's experiment. Experiments carried out by Pasteur and Spallanzoni might probably due to luck too, because the sterillization techniques they used would often not kill the endospores. 
• Artificial spleen (biospleen) that was "invented" recently is able to filter the blood from all types of pathogens, by using a magnetic nanobeads (coated with mannose-binding lectin, MBL, a protein found in humans that binds to sugar molecules on the surfaces of 90 different bacteria, viruses and fungi). It means that the device can attach to many kinds of pathogens and together with them, they are filtered out of the blood.
• Why do wine and beer turn sour (especially when exposed to air)? Pasteur found that when the wine turned sour, there was a proliferation of bacterial cells which were producing lactic acid (so the wine turn sour). How to prevent spoilage of these beverages? Pasteur suggested to heat the wine gently at about 49ºC to kill the bacterial cells. The idea of heating to kill microbes was then applied to milk and thus the idea of pasteurization was born.
• Louise Pasteur had many other contributions such as inventing the technique of sterilization (by boiling or heating instruments and food), rescuing the crisis in French silk industry, producing vaccines for anthrax, rabies  etc.
• How did Pasteur discover vaccination? Before this, Pasteur developed techniques for culturing and examining disease-causing bacteria, such as Staphylococcus pyogenes and Vibrio cholerae. When testing Vibrio cholerae on chicken, Pasteur expected the chicken to get sicked but the chicken got immunity instead because the bacteria were old and no longer virulent.
• After Louise Pasteur had stroke, his work was continued by his wife Marie Laurent Pasteur.

Reflection on this topic
I was really amazed at the spirit of scientists when reading the history of microbiology. Here are a few things that make me feel incredible :

1. How could Robert Hooke draw such detailed picture of thin slice of cork? I remembered once I complained why science students (especially biology) need to draw specimens while we can just take the photos or download it. Plus I used to think that we are not art students, so the drawing will of course look terrible. But from the picture drawn by Robert Hooke, it can be seen that he had actually put a lot of efforts in drawing it. No matter how detailed or how fussy the specimen is, he would still try his best to draw it out. This is the spirit that I should learn from him, to be whole-heartedly and serious in whatever I'm doing.
2. The invention and innovation of Antoine van Leeuwenhoek in making his own crafted microscope has made a huge step in microbiology. By using the very simple microscope, he was the first in this world to observe microorganisms which he referred as animalcules. This discovery was an exciting news to everybody because it was like a totally new stuff back then. I personally think that Leeuwenhoek must be in overwhelming awe when he found out those microbes that we can't see with naked eyes.
   
3. The attitude of Antoine van Leeuwenhoek in pursuing knowledge is inspiring. Time he spent in his work was not to gain the praise he enjoyed, but merely to crave after knowledge. Not asking for any title or accreditation, Leeuwenhoek was just eager to know more about the world, that's curiosity.
4. The participation of scientists in giving opinions (or arguments) to seek the truths. When the spontaneous generation was proposed, different opinions were voiced out and the scientists did few tests to find out evidence of it or against it. One of the experiment was done by John Needham, which was then disapproved by Lazzaro Spallanzani, which was also criticized by others, until the proposal of "Biogenesis" concept (living cells can arise only from pre-existing living cells. To prove the concept of biogenesis, again, scientist (Louise Pasteur) did few experiments to prove it. The knowledge that we know now is contributed by lots of brilliant people. They discovered every knowledge step by step, bit by bit. The process of discovery was a long way to go, but they still hold on to it. That's another spirit that I should instill, the spirit of discovery.
5. As told by Dr. Wan, we should really create a community of learning in this microbe group. Knowledge must be shared, and discussion should be held more often to instill the spirit of scientists within us. We ourselves should start to create the atmosphere of learning to discover and explore, instead of just memorizing. 
6. Be unusual! When buying food or drinks, look at the content for the information which we can relate to microbiology. For example, we can find pasteurization and UHT in milk.
7. As said by Dr. Wan, next time if we have the opportunity to travel to Paris, take some time to visit Pasteur Institute. This is the first time I heard about the institute and actually feel interested to visit the place even though it sounds very "scientific". Pasteur is indeed a very brilliant scientist, so the place is worthwhile to go besides Eiffel tower !
8. When reading the history of Edward Jenner, I found it very difficult to accept the fact that he inoculated his own son with swinepox and smallpox. Maybe because I haven't figured out the intentions behind it. I need to do some readings and will come to this issue again.