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 BioremediationAgriculture Biotechnology/ Genetic engineering Food microbiology Industrial Microbiology Normal microbiota Disease causing microorganisms

Common Ancestor Gave rise to 3 Domains Two prokaryotic Two prokaryotic Bacteria and Archaea One eukaryotic One eukaryoticEukarya

Prokaryotes Asexual; unicellular, no membrane bound organelles Archaea Not known to be human pathogens Not known to be human pathogens Usually found in extreme environments Usually found in extreme environmentsBacteria Some pathogenic Some pathogenic Multiple morphological and physiological differences from archaea Multiple morphological and physiological differences from archaea

Rod Shaped Bacteria Many Klebisella pneumoniae cells Round Archaea Methanococcus janaschii, with numerous flagella attached to one side

Eukaryotes Unicellular or multicellular Sexual and asexual reproduction Multiple membranous organelles Algae Algae Unicellular or multicellular Photosynthetic High morphological diversity Not pathogenic

Cymatopleura Volvox Macrocystis pyrifera Gelidium pulchrum Alexandrium tamarense

Amanita muscaria Aspergillus flavus Rhizopus Saccharomyces cerevisiae FungiFungi Unicellular or multicellularUnicellular or multicellular Absorb nutrients from their environmentAbsorb nutrients from their environment Primarily opportunistic pathogensPrimarily opportunistic pathogens

Protozoa ProtozoaUnicellular Most are mobile Pseudopods, Flagella, Cilia Pseudopods, Flagella, Cilia Absorb nutrients from environment or live as parasites Manyare pathogenic

Giardia lamblia Amoeba Paramecium

Helminths Helminths Multi-cellular animals Flatworms and round worms Many are pathogenic Only some life stages microscopic Taenia taeniformis Necator americanus

Viruses Obligatory intracellular parasite Obligatory intracellular parasite No true cellular organization No true cellular organization Living or non-living??? Living or non-living??? HIV virus on the surface of a CD4+ cell Bacteriophages

Size in the Microbial World

History of Microbiology Robert Hooke Anton van Leeuwenhoek "animalcules" "animalcules" Schleiden and Schwann- 1838/39 Cell theory Cell theory

Spontaneous Generation Franscesco Redi – 1668 John Needham – 1745 Lazzaro Spallanzani

Rudolf Virchow Louis Pasteur – 1861 Aseptic techniques Aseptic techniques

Golden Age of Microbiology (1874 – 1914)

Support theories that invisible agents cause disease Ignaz Semmelweis Ignaz Semmelweis Childbed fever Joseph Lister Joseph Lister Aseptic surgery John Tyndall John Tyndall Microbes in dust, some heat resistant

Germ Theory of Disease Pasteur Pasteur Fermentation (1857) and pasteurization (1864) Robert Koch Robert Koch Walther Hesse – 1882 Walther Hesse – 1882

Vaccination Edward Jenner – 1798 Edward Jenner – 1798 Smallpox vaccine Louis Pasteur – 1880 Louis Pasteur – 1880Avirulence Rabies vaccine

Chemotherapy 1908, Paul Ehrlich Salvarsan – treatment for syphilis 1928, Alexander Fleming Discovered properties of penicillin , 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 Toxicity Resistance Resistance Lack of adequate anti- viral drugs Lack of adequate anti- viral drugs

Infectious disease remains a threat 750 million cases each year in US 750 million cases each year in US Emerging diseases Factors associated with emerging disease Microbial evolution Microbial evolution Changing human behavior/lifestyles Changing human behavior/lifestyles Complacency of human population Complacency of human population Population expansion/global travel Population expansion/global travel