2 Microbes in Our Lives1-1 List several ways in which microbes affect our lives.
3 Microbes in Our LivesMicroorganisms are organisms that are too small to be seen with the unaided eyeGerm refers to a rapidly growing cell
4 Microbes in Our Lives A few are pathogenic (disease-causing) Decompose organic wasteAre producers in the ecosystem by photosynthesisProduce industrial chemicals such as ethanol and acetoneProduce fermented foods such as vinegar, cheese, and breadProduce products used in manufacturing (e.g., cellulase) and disease treatment (e.g., insulin)
5 Microbes in Our Lives Knowledge of microorganisms Allows humans to Prevent food spoilagePrevent disease occurrenceLed to aseptic techniques to prevent contamination in medicine and in microbiology laboratories
6 Naming and Classifying Microorganisms 1-2 Recognize the system of scientific nomenclature that uses two names: a genus and a specific epithet.1-3 Differentiate the major characteristics of each group of microorganisms.1-4 List the three domains.
7 Naming and Classifying Microorganisms Linnaeus established the system of scientific nomenclatureEach organism has two names: the genus and specific epithet
8 Scientific Names Are italicized or underlined The genus is capitalized; the specific epithet is lowercaseAre “Latinized” and used worldwideMay be descriptive or honor a scientist
9 Scientific NamesAfter the first use, scientific names may be abbreviated with the first letter of the genus and the specific epithet:Escherichia coli and Staphylococcus aureus are found in the human bodyE. coli is found in the large intestine, and S. aureus is on skin
10 Types of Microorganisms BacteriaArchaeaFungiProtozoaAlgaeVirusesMulticellular animal parasites
11 Figure 1.1 Types of microorganisms. SporangiaBacteriaPreyPseudopodsHIVsCD4+ T cell
12 Bacteria Prokaryotes Peptidoglycan cell walls Binary fission For energy, use organic chemicals, inorganic chemicals, or photosynthesis
13 Figure 1.1a Types of microorganisms. Bacteria(a) The rod-shaped bacterium Haemophilus influenzae, one of the bacterial causes of pneumonia.
14 Archaea Prokaryotic Lack peptidoglycan Live in extreme environments Include:MethanogensExtreme halophilesExtreme thermophiles
16 Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy Molds and mushrooms are multicellular, consisting of masses of mycelia, which are composed of filaments called hyphaeYeasts are unicellular
24 Multicellular Animal Parasites EukaryotesMulticellular animalsParasitic flatworms and roundworms are called helminthsMicroscopic stages in life cycles
25 Rod of Asclepius, symbol of the medical profession. Figure 1.6 Parasitology: the study of protozoa and parasitic worms.Rod of Asclepius, symbol of the medical profession.A parasitic guinea worm (Dracunculus medinensis)is removed from the subcutaneous tissue of a patientby winding it onto a stick. This procedure may havebeen used for the design of the symbol in part (a).
26 Classification of Microorganisms Three domainsBacteriaArchaeaEukaryaProtistsFungiPlantsAnimals
27 Figure 10.1 The Three-Domain System. EukaryaOrigin of mitochondriaFungiAnimalsBacteriaOrigin of chloroplastsAmebaeMitochondriaSlime moldsArchaeaCyanobacteriaPlantsCiliatesExtremehalophilesProteobacteriaGreenalgaeChloroplastsMethanogensDinoflagellatesDiatomsHyperthermophilesGram-positivebacteriaEuglenozoaGiardiaThermotogaHorizontal gene transferoccurred within thecommunity of early cells.Mitochondrion degeneratesNucleoplasm grows larger
28 The Germ Theory of Disease 1835: Agostino Bassi showed that a silkworm disease was caused by a fungus1865: Pasteur believed that another silkworm disease was caused by a protozoan1840s: Ignaz Semmelweis advocated handwashing to prevent transmission of puerperal fever from one obstetrical patient to another
29 The Germ Theory of Disease 1860s: Applying Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases, Joseph Lister used a chemical disinfectant to prevent surgical wound infections
31 The Germ Theory of Disease 1876: Robert Koch proved that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, to prove that a specific microbe causes a specific disease
33 Vaccination1796: Edward Jenner inoculated a person with cowpox virus, who was then protected from smallpoxVaccination is derived from vacca, for cowThe protection is called immunity
34 The Birth of Modern Chemotherapy Treatment with chemicals is chemotherapyChemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibioticsAntibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes
35 The First Synthetic Drugs Quinine from tree bark was long used to treat malariaPaul Ehrlich speculated about a “magic bullet” that could destroy a pathogen without harming the host1910: Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis1930s: sulfonamides were synthesized
36 A Fortunate Accident—Antibiotics 1928: Alexander Fleming discovered the first antibioticFleming observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus1940s: Penicillin was tested clinically and mass produced
37 Normal bacterial colony Area of inhibition of bacterial growth Figure 1.5 The discovery of penicillin.NormalbacterialcolonyArea ofinhibition ofbacterialgrowthPenicilliumcolony
38 Modern Developments in Microbiology Bacteriology is the study of bacteriaMycology is the study of fungiVirology is the study of virusesParasitology is the study of protozoa and parasitic worms
39 Modern Developments in Microbiology Immunology is the study of immunityVaccines and interferons are being investigated to prevent and cure viral diseasesThe use of immunology to identify some bacteria according to serotypes was proposed by Rebecca Lancefield in 1933
41 Recombinant DNA Technology Microbial genetics: the study of how microbes inherit traitsMolecular biology: the study of how DNA directs protein synthesisGenomics: the study of an organism’s genes; has provided new tools for classifying microorganismsRecombinant DNA: DNA made from two different sourcesIn the 1960s, Paul Berg inserted animal DNA into bacterial DNA, and the bacteria produced an animal protein
42 Recombinant DNA Technology 1941: George Beadle and Edward Tatum showed that genes encode a cell’s enzymes1944: Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA is the hereditary material1961: François Jacob and Jacques Monod discovered the role of mRNA in protein synthesis
43 Nobel Prizes for Microbiology Research * The first Nobel Prize in Physiology or Medicine1901* von Bering Diphtheria antitoxin1902 Ross Malaria transmission1905 Koch TB bacterium1908 Metchnikoff Phagocytes1945 Fleming, Chain, Florey Penicillin1952 Waksman Streptomycin1969 Delbrück, Hershey, Luria Viral replication1997 Prusiner Prions2005 Marshall & Warren H. pylori & ulcers2008 zur Hausen HPV & cancer2008 Barré-Sinoussi& Montagnier HIV
44 Microbial EcologyBacteria recycle carbon, nutrients, sulfur, and phosphorus that can be used by plants and animals
45 Bioremediation Bacteria degrade organic matter in sewage Bacteria degrade or detoxify pollutants such as oil and mercury
46 Solid municipal wastes being turned by a specially designed machine Figure Composting municipal wastes.Solid municipal wastes being turned by a specially designed machine
47 Biological Insecticides Microbes that are pathogenic to insects are alternatives to chemical pesticides in preventing insect damage to agricultural crops and disease transmissionBacillus thuringiensis infections are fatal in many insects but harmless to other animals, including humans, and to plants
48 BiotechnologyBiotechnology, the use of microbes to produce foods and chemicals, is centuries old
49 Figure 28.8 Making cheddar cheese. The milk has been coagulated by the action of rennin (forming curd) and is inoculated with ripening bacteria for flavor and acidity. Here the workers are cutting the curd into slabs.The curd is chopped into small cubes to facilitate efficient draining of whey.The curd is milled to allow even more drainage of whey and is compressed into blocks for extended ripening. The longer the ripening, the more acidic (sharper) the cheese.
50 BiotechnologyRecombinant DNA technology, a new technique for biotechnology, enables bacteria and fungi to produce a variety of proteins, including vaccines and enzymesMissing or defective genes in human cells can be replaced in gene therapyGenetically modified bacteria are used to protect crops from insects and from freezing
51 Normal MicrobiotaBacteria were once classified as plants, giving rise to use of the term flora for microbesThis term has been replaced by microbiotaMicrobes normally present in and on the human body are called normal microbiota
53 Normal Microbiota Normal microbiota prevent growth of pathogens Normal microbiota produce growth factors, such as folic acid and vitamin KResistance is the ability of the body to ward off diseaseResistance factors include skin, stomach acid, and antimicrobial chemicals
54 Biofilms Microbes attach to solid surfaces and grow into masses They will grow on rocks, pipes, teeth, and medical implants
55 Figure 1.8 Biofilm on a catheter. Staphylococcus
56 Infectious DiseasesWhen a pathogen overcomes the host’s resistance, disease resultsEmerging infectious diseases (EIDs): new diseases and diseases increasing in incidence
57 Drug Resistance – The New Threat in Microbiology (i.e. MRSA) Methicillin-resistant Staphylococcus aureus1950s: Penicillin resistance developed1980s: Methicillin resistance1990s: MRSA resistance to vancomycin reportedVISA: vancomycin-intermediate-resistant S. aureusVRSA: vancomycin-resistant S. aureus
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