General Microbiology BIOL 2013 What is Science Study of the natural world Scientific Method 1 Observe some aspect of the natural world 2 Come up with a tentative description called a hypothesis that is consistent with the observation Use the hypothesis to make predictions 3 Test those predictions by experimentation or further observations and modify the hypothesis in light of the results 4 When consistency is obtained between hypothesis and experiments and or observations the hypothesis becomes a theory A theory is a framework within which observations are explained and predictions are made 5 Law Ockham s Razor What s that William of Ockham 14th Century The simplest theory is probably the correct one What is Microbiology Study of microorganisms Study of objects that can t be seen with the human eye What are the branches of Microbiology based on organisms studied American Society for Microbiology Bacteriology Virology disagreements on whether viruses are alive or not Mycology study of Fungi Algology study of Algae Protozoology History of Microbiology What aspects of microbiology are mentioned in the Bible Leprosy contagious bacterial disease Wine yeast fermentation When did the science of microbiology begin 17th century microscope 1665 Robert Hooke First observation of cells with the van Leeuwenhoek First observation of live organisms with the microscope 1673 Father of the microscope These two were the first to REPORT their Reported his findings to the Royal Society of findings London When did the science of microbiology begin Mid 1800 s Father of microbiology Pasteur Fermentation 1857 Figure 1 4 page 10 Milestones in microbiology highlighting those that occurred during the Golden Age of Microbiology Figure 1 2 a page 7 Anton van Leeuwenhoek s microscopic observations By holding his brass microscope toward a source of light van Leeuwenhoek was able to observe living organisms too small to be seen with the unaided eye The other specimen was placed on the tip of the adjustable point and viewed from the other side through a tiny nearly spherical lens The highest magnification possible from his microscope was about x300 Some of van Leeuwenhoek s drawings of bacteria made in 1683 the letters represent various shapes of bacteria Figure 1 2 b page 7 Louis Pasteur Father of Microbiology Known for disproving the theory of spontaneous generation Nothing spontaneously generates Figure 1 3 page 9 Disproving the theory of spontaneous generation According to the theory of spontaneous generation life can arise spontaneously from nonliving matter such as dead corpses and soil Pasteur s experiment demonstrated that microbes are present in nonliving matter air liquids and solids Pasteur demonstrated that microbes are responsible for food spoilage leading researchers to the connection between microbes and disease His experiments and observations provided the basis of aseptic techniques which are used to prevent microbial contamination as shown in the photo at right Pasteur first poured beef broth into a long necked flask Microorganisms were present in the broth Next he heated the neck of the flask and bent it into an S shape then he boiled the broth for several minutes Microorganisms were not present in the broth after boiling 1 2 3 Microorganisms did not appear in the cooled solution even after long periods The bend in the neck prevented microbes from entering the flask Microorganisms were not present even after long periods Controls for Pasteur s Experiment Pour meat broth into flask watch Pour meat broth into flask bend neck watch Pour meat broth into flask boil watch Clicker question which was not a control Pour meat broth bend neck boil watch How was Pasteur lucky No bacteria in there to start with that were resistant to high heat aka endospores Apparently no endospores in the meat broth Most resistant forms of life Koch s Postulates 1 The same pathogen must be present in every case of the disease 2 The pathogen must be isolated from the diseased host and grown in pure culture 3 The pathogen from the pure culture must cause the disease when it is inoculated into a healthy susceptible laboratory animal 4 The pathogen must be isolated from the inoculated animal and must be shown to be the original organism Figure 14 3 page 407 Koch s postulates understanding disease 1 Microorganisms are isolated from a diseased or dead animal 2 The microorganisms are grown in pure culture The microorganisms are identified The microorganisms are injected into a healthy laboratory animal Disease is reproduced in a lab animal The microorganisms are isolated from this animal and grown in pure culture Microorganisms are identified The microorganism from the diseased host caused the same disease in the lab host 3 4 5 According to Koch s postulates a specific infectious disease is caused by a Koch s postulates help determine the etiology of disease the first step in specific microbe treatment and prevention Microbiologists use these steps to identify causes of emerging diseases Exceptions bacteria that cannot be isolated outside of an organism Will not grow 2 Treponema pallidum causes syphilis 3 HIV causes AIDS Finding a susceptible lab animal is difficult Typically inject the disease into chimpanzees but the HIV never turns into AIDS Thomas Bramwell Welch 1825 1903 First Pasteurization of grape juice 1869 instead Was very concerned with using wine in religious ceremonies Wanted to use grape juice Since then certain religious denominations can use grape juice instead of wine What life forms do we have on planet Earth Figure 10 1 page 274 The three domain system Bacteria mitochondria cyanobacteria chloroplasts proteobacteria gram positive bacteria thermotoga Archaea methanogens extreme halophiles hyperthermophiles Eukarya green algae plants slime molds amebae fungi animals ciliates dinoflagellates diatoms euglenozoa giardia All organisms evolved from cells that formed over 3 billion The DNA passed on from ancestors is described as years ago conserved The Domain Eukarya includes the Kingdoms Fungi Plantae and Animalia as well as protists The Domains Bacteria and Archaea are prokaryotes How big are cells Eukaryotes Prokaryotes Mycoplasma 10 100 uM 0 2 2 uM 0 2 uM Viruses 0 02 0 3 uM 20 300 nM How much bigger is an average eukaryotic cell than an average prokaryotic cell with respect to volume Assume each cell is cubic in shape and the eukaryote is 20 uM in one dimension and the prokaryote is 2 uM in one dimension The