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Unformatted text preview: Chapter 1 The Microbial World and You What are microorganisms?
Too small to be seen with the unaided eye True cellular forms grow and reproduce Ubiquitous Both helpful and problematic Nomenclature
Carolus Linaes Each organism given two names genus species Staph = cluster; aureus Latin for golden Ex. Staphylococcus aureus Common Ancestor
Gave rise to 3 cell lines 2 prokaryotic Bacteria and Archaea One eukaryotic Types of microbes Bacteria, archaea Fungi, protozoa, algae, helminths Viruses Prokaryotes
Archaea Single-celled; asexual Not known to be human pathogens Usually found in extreme environments methanogens, halophiles, thermophiles Bacteria Single-celled; asexual Cell wall differs from archaea Greater diversity Rod Shaped Bacteria Klebisella pneumoniae Eukaryotes Fungi
Unicellular or multicellular Hyphae; mycelia Absorb nutrients from their environment Some are pathogenic Algae
Unicellular or multicellular Photosynthetic High morphological diversity Not pathogenic Protozoa
Unicellular Most are mobile Pseudopods, Flagella, Cilia Absorb nutrients from environment or live as parasites Many are pathogenic Helminths
Multi-cellular Flatworms and round worms Many are pathogenic Only some stages are microscopic Viruses Obligatory intracellular parasite No cellular organization Living or non-living??? Genetic core surrounded by a protein coat Have RNA or DNA but not both Examples of Fungi
Saccharomyces cerevisiae Rhizopus Aspergillus flavus Amanita muscaria Examples of Potozoans Amoeba Giardia lamblia Examples of Algae Cymatopleura Volvox Macrocystis pyrifera Alexandrium tamarense Gelidium pulchrum Examples of Helminthes Taenia taeniformis Necator americanus Examples of Viruses HIV virus on the surface of a CD4+ cell Bacteriophages Size in the Microbial World How are microbes classified?
How do we identify each other?
With microbes, vision is not the best answer. Morphology and stains Chemical makeup of cells Enzymatic properties Genetics How microbiology got started as a science
Robert Hooke (1665) Anton van Leeuwenhoek (16741723) Matthias Schleiden and Theodor Schwann Spontaneous Generation Franscesco Redi 1668 John Needham 1745 Spallanzani - 1765 Virchow 1858 Pasteur 1861 Golden Age of Microbiology (1874 1914) Fermentation yeasts convert sugars to alcohol bacteria change alcohol into vinegar product is heated just enough to kill most microbes present without damaging the product Pasteurization Germ Theory of Disease Pasteur Joseph Lister Robert Koch Vaccination Edward Jenner 1798 Louis Pasteur 1880 Chemotherapy
Alexander Fleming Penicillium notatum - mold Problems with modern chemotherapeutics Toxicity Resistance Lack of adequate anti- virals Specialties of Microbiology
Bacteriology Mycology Phycology Parasitology Virology Epidemiology Immunology Why study microbes?
Recycling vital elements Sewage treatment Bioremediation Pest control (e.g. Bacillus thuringiensis) Molecular Biology and Biotechnology Normal microbiota Food industries Disease causing microorganisms Antibiotics Present and Future Challenges
Infectious disease remains a threat 750 million cases each year in US Emerging diseases Increased occurrence with wider distribution
Seemingly new diseases Actually not new Changing lifestyles Genetic changes in organisms Factors associated with emerging disease Resurgence of old diseases Diseases thought to be "defeated" increasing in frequency Reasons for resurgence Increase travel Unvaccinated individuals Chronic disease caused by bacteria Many disease once thought caused by environmental stressors actually caused by bacteria
Example: gastric ulcers Causative agent Helicobacter pylori ...
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- Spring '06