Introduction to Microbiology What is science The Study of the natural world based on the observation and interpretation of natural phenomenon Emphasis on evidence not belief Scientific Method o Observe some aspect of the natural world o Come up with a tentative description or hypothesis that is consistent with the observation Uses the hypothesis to make predictions Note hypothesis does not equal theory You need actual evidence to make a theory o Test your predictions by experimentation or further observations The or is important When you can t control a phenomenon in an experimental setting you gotta observe and collect more data You can modify the hypothesis in light of the results o When consistency is obtained between hypothesis and experiments observations the hypothesis becomes a theory A theory is a framework within which observations are explained and predictions are made It is correct until you can come up with evidence that proves otherwise o If there is a whole lot of evidence backing up your theory it may eventually become a law Laws are irrefutable Ockham s Razor a sort of rule of thumb created by William of Ockham in the 14th century He states that the simplest theory is more likely to be the correct theory What is Microbiology The study of organisms too small to be seen with the naked eye There are five branches of microbiology you should know o Bacteriology the study of bacteria o Mycology the study of fungi o Protozoology the study of protozoans o Virology the study of viruses This branch is somewhat separate from the others because there is a disagreement as to whether or not viruses are alive History of Microbiology Aspects of microbiology are present as far back as Biblical times Remember of the stuff about leprosy a contagious bacterial disease the importance of wine made possible through yeast fermentation o PS watch out for armadillos they are known to still carry leprosy Carville LS happens to be something of a hop spot for lepers We know how to treat it in the US but peeps all over African countries still die of it all the time The incubation period is 18 years 17th century the microscope was invented In 1665 Robert Hooke discovered cells BTW Hooke was also a crazy awesome inventor 1673 van Leeuwenhoek was the first to observe live microorganisms and publish his findings o He was probably not the first guy to ever observe microorganisms but he s important because he was brave enough to publish his findings into a world of very superstitious people who would have thought he was crazy o He s also thought of as the Father of the microscope though he was by no means the first guy to use one 1857 1911 the Golden Age of Microbiology If we were asked when microbiology became a fully fledged scientific discipline we should say 1857 200 years after the first observation of cells 1857 Louis Pasteur discovered and explained fermentation and then invented the process of pasteurization in 1864 o He s often called the Father of Microbiology He disproved spontaneous generation in 1861 by using this experiment o Louis poured beef broth into a long neck flask Microorganisms were present He bent it into an s shape and then boiled the broth for several minutes Microorganisms were killed After that microorganisms did not appear in the cooled solution even after long periods Thus since the broth had no exposure to outside the flask no microorganisms could get in and no microorganisms spontaneously generated o He had three controls or trials without the tested variables in the experiment to see what happens normally for comparative purposes He had one flask in which he poured in meat broth and observed Another he poured in the broth and bent the neck The last one he added the broth and boiled it without bending the neck This way he could see which variable was actually changing the results o He was lucky that there were no endospores in his broth Endospores are super resistance microorganisms that could have survived the heat of the boiling process Commonly found in soil Here s another important guy Robert Koch pronounced like Coke who created the Germ Theory of Disease in 1876 He came up with Koch s Postulates or a process to prove whether or not a disease can be correlated to it s causal organism or pathogen He commonly used white mice for this o First Postulate is more of a statement than a step in the procedure The same pathogen must be present in every case of the disease o The pathogen must be isolated from the diseased host and grown in pure culture Koch invented the process for pure culture in 1881 Exception Treponema pallidum This bacterium cannot be isolated in pure culture Good thing syphilis is very curable o The pathogen from the pure culture is then inoculated into a healthy susceptible host Exception HIV The only susceptible host that would exhibit AIDS if you inoculated them with HIV is humans And that s unethical You can inoculate it in chimps but they never contracted AIDS from it o If the new host dies and the pathogen can be re isolated then you have for sure found your causal organism Good job o Here s a fun fact in 1976 it took 6 months to isolate the pathogen that causes Legionare s Disease Thomas Bramwell Welch 1825 1903 wanted to derive a non alcoholic communion wine So he made the first pasteurized grape juice in 1869 Welch s Grape Juice is named after him Categorizing Life Forms What is the definition of life There actually isn t a universally accepted definition but Dr Kral says that anything with cells counts as living o This is important when discussing whether or not viruses are alive because they technically do not have cells o Other parts of his definition include an organism s ability to reproduce grow interact with it s environment and have a metabolism We use a three domain system as of 1992 Figure 10 1 page 274 o Bacteria Prokaryotes o Archaea Prokaryotes These guys make up the biggest group of organisms on earth on an individual level Most are anaerobic meaning they cannot tolerate oxygen o Eukarya Eukaryotes This is us among other things The sizes of things The smallest size a human can see with the naked eye is 100 micrometers Micrometers uM are a millionth of a meter o Eukaryotes are 10 100 uM Prokaryotes are 2 2 uM Viruses are 02 3 uM o Mycoplasma are considered to be the smallest known living organisms again only if you don t consider viruses as alive They are prokaryotes that cause the respiratory illness known as walking pneumonia