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Chapter 1 The Microbial World and You What are microorganisms? Too small to be seen with the unaided eye True cellular forms Ubiquitous Both helpful and problematic Scope and Relevance of Microbiology First living organisms on the planet Live everywhere life is possible Largest component of Earth's biomass Ecosystems depends on their activities Why study microbes? Recycling vital elements Bioremediation Agriculture Biotechnology/ Genetic engineering Food microbiology Industrial Microbiology Normal microbiota Disease causing microorganisms Common Ancestor Gave rise to 3 Domains Two prokaryotic Bacteria and Archaea One eukaryotic Eukarya Prokaryotes Asexual; unicellular, no membrane bound organelles Archaea Not known to be human pathogens Usually found in extreme environments Bacteria Some pathogenic Multiple morphological and physiological differences from archaea Rod Shaped Bacteria Round Archaea Many Klebisella pneumoniae cells Methanococcus janaschii, with numerous flagella attached to one side Eukaryotes Unicellular or multicellular Sexual and asexual reproduction Multiple membranous organelles Algae Unicellular or multicellular Photosynthetic High morphological diversity Not pathogenic Cymatopleura Volvox Macrocystis pyrifera Gelidium pulchrum Alexandrium tamarense •Fungi •Unicellular or multicellular •Absorb nutrients from their environment •Primarily opportunistic pathogens Saccharomyces cerevisiae Rhizopus Aspergillus flavus Amanita muscaria Protozoa Unicellular Most are mobile Pseudopods, Flagella, Cilia Absorb nutrients from environment or live as parasites Manyare pathogenic Amoeba Giardia lamblia Paramecium Helminths Multi-cellular animals Flatworms and round worms Many are pathogenic Only some life stages microscopic Taenia taeniformis Necator americanus Viruses Obligatory intracellular parasite No true cellular organization Living or non-living??? HIV virus on the surface of a CD4+ cell Bacteriophages Size in the Microbial World History of Microbiology Robert Hooke -1665 Anton van Leeuwenhoek 1673 "animalcules" Schleiden and Schwann1838/39 Cell theory Spontaneous Generation Franscesco Redi – 1668 John Needham – 1745 Lazzaro Spallanzani - 1765 Rudolf Virchow -1855 Louis Pasteur – 1861 Aseptic techniques Golden Age of Microbiology (1874 – 1914) Support theories that invisible agents cause disease Ignaz Semmelweis - 1840 Childbed fever Joseph Lister - 1867 Aseptic surgery John Tyndall Microbes in dust, some heat resistant Germ Theory of Disease Pasteur Fermentation (1857) and pasteurization (1864) Robert Koch - 1876 Walther Hesse – 1882 Vaccination Edward Jenner – 1798 Smallpox vaccine Louis Pasteur – 1880 Avirulence Rabies vaccine Chemotherapy 1908, Paul Ehrlich Salvarsan – treatment for syphilis 1928, Alexander Fleming Discovered properties of penicillin 1935-36, Gerhard Domagk & Ernest Fourneau Development of sulfa drugs 1940, Selman Waksman Isolated antibiotic from Streptomyces 1940, Howard Florey & Ernest Chain Preformed clinical trials and mass produced penicillin Problems with modern chemotherapeutics Toxicity Resistance Lack of adequate anti- viral drugs Infectious disease remains a threat 750 million cases each year in US Emerging diseases Factors associated with emerging disease Microbial evolution Changing human behavior/lifestyles Complacency of human population Population expansion/global travel
