KNOW the MICROBES. What are microbes? What are the different types? Who saw them first? How small are they? How do they look?

Transcription

1 KNOW the MICROBES What are microbes? What are the different types? Who saw them first? How small are they? How do they look? -

2 PowerPoint Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University C H A P T E R 1 A Brief History of Microbiology

3 What are microorganisms? Or Microbes? micro-scopic living organisms (entire) need a microscope to see them

4 know the micron = µm = millionth part of meter

5 Figure 3.4 Approximate size of various types of cells. ~10 um Red Blood Cells 1.5mm 1500 um Width of penny = 1500

6 Antoni van Leeuwenhoek 1674: First to see the microbial world

7 Lens Specimen holder Began making and using simple microscopes Often made a new microscope for each specimen Figure 1.2 Reproduction of Leeuwenhoek's microscope. -leeuwenhoek-microscope-replica

8 Figure 1.3 The microbial world. Leeuwenhoek observed a drop of pond water "animalcules = protozoa beasties = bacteria By end of 19th century, these organisms were called microorganisms and microbes

9 Pond Scum Under the Microscope

10 Real beasties

11 The Early Years of Microbiology How Can Microbes Be Classified? Carolus Linnaeus developed taxonomic system for naming plants and animals and grouping similar organisms together Leeuwenhoek grouped microorganisms into six categories as follows: Bacteria Archaea Fungi Protozoa Algae Small multicellular animals

12 There are 3 major types of living organisms (they all have cell(s)) One tree of life 3 domains Bacteria Archae Eukarya

13 Figure 1.13 (a) Domain Bacteria (b) Domain Archaea 2 µm 2 µm (c) Domain Eukarya Kingdom Animalia 100 µm Kingdom Plantae Kingdom Fungi Animals: Protozoa Plants: Algae Fungi Protists

14 There are 3 major types of living organisms One tree of life 3 domains Bacteria prokaryotic Archae Eukarya eukaryotic

15 All living organisms have cell(s) Some are unicellular others multicellular How many different types of cells There are only 2 types of cells Prokaryotic cells Eukaryotic cells Membrane around nucleus Membrane-bound organelles

16 Figure 1.4 Eukaryotic cell Membrane Cytoplasm DNA (no nucleus) Membrane Prokaryotic cell Nucleus (membraneenclosed) Membraneenclosed organelles DNA (throughout nucleus) 1 µm

17 Figure 1.4 Cells of the bacterium Streptococcus (dark blue) and two human cheek cells. Prokaryotic bacterial cells Nucleus of eukaryotic cheek cell

18 Any of these 3 which is a microscopic organism is a microbe One tree of life 3 domains all all some Bacteria prokaryotic Archae Eukarya eukaryotic

19 prokaryotic cells vs eukaryotic cells differences and similiarities Use self-study guide to summarize

20 So microbes can be prokaryotic or eukaryotic And they all have cell(s) But there are also microbes without cells bacteria Cellular and Acellular Acellular = viruses

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22 The Early Years of Microbiology How Can Microbes Be Classified? Bacteria and Archaea (Prokaryotic Microbes) Unicellular and lack nuclei Much smaller than eukaryotes Most have cell walls but Bacterial cell walls contain peptidoglycan; Archaeal cell walls composed of polymers other than peptidoglycan

23 The Early Years of Microbiology Eukaryotic Microbes Protozoa (Animals) Single-celled eukaryotes Similar to animals in nutrient needs and cellular structure Live freely in water; some live in animal hosts Most are capable of locomotion by Pseudopods cell extensions that flow in direction of travel Cilia numerous short protrusions that propel organisms through environment Flagella extensions of a cell that are fewer, longer, and more whiplike than cilia

24 Nucleus Pseudopods Cilia Flagellum Figure 1.6 Locomotive structures of protozoa.

25 The Early Years of Microbiology Eukaryotic Microbes Algae (Plants) Unicellular or multicellular Photosynthetic Categorized on the basis of pigmentation and composition of cell wall

26 Eukaryotic Microbes Fungi Eukaryotic (have membrane-bound nucleus) Obtain food from other organisms Possess cell walls Include Molds multicellular; grow as long filaments Yeasts unicellular

27 Figure 1.5 Fungi. Hyphae Spores Budding cells

28 The Early Years of Microbiology Other organisms that microbiologists study Parasites Viruses (acellular)

29 Figure 1.9 A colorized electron microscope image of viruses infecting a bacterium. Virus Bacterium Viruses assembling inside cell

30 Figure 1.8 An immature stage of a parasitic worm in blood. Why Parasites? Red blood cell Immature stages are microscopic

31 youtube-history-micro tube.com/watch? v=zrirf5baat4&f eature=youtu.be

32 The Golden Age of Microbiology Scientists searched for answers to four questions (late 1800 to but long after Leeuwenhoek why?) 1) Is spontaneous generation of microbial life possible? 2) What causes fermentation? 3) What causes disease? 4) How can we prevent infection and disease?

33 Q1- Is spontaneous generation of microbial life possible? Is there growth of microbes? NO But Critics said 1) sealed vials did not allow enough air for organisms to survive and Lazzaro Spallanzani's experiments 2) prolonged heating destroyed the "life force"

34 Figure 1.11 Louis Pasteur.

35 Figure 1.12 Pasteur's experiments with "swan-necked flasks." There is NO spontaneous generation of microbes Cells come from parent Cells

36 The Golden Age of Microbiology Q2- What Causes Fermentation? Spoiled wine threatened livelihood of vintners Vintners funded research of methods to promote production of alcohol and prevent spoilage during fermentation Some believed air caused fermentation; others insisted living organisms caused fermentation

37 Figure 1.13 The scientific method, which forms a framework for scientific investigation or research. Criticism/doubt is key Results H E R accept OR not accept

38 Figure 1.14 How Pasteur applied the scientific method in investigating the nature of fermentation. Yeast alcohol Bacteria acid

39 The Golden Age of Microbiology Pasteur's experiments Led to the development of pasteurization Process of heating liquids just enough to kill most bacteria Began the field of industrial microbiology or biotechnology (Intentional use of microbes for manufacturing products)

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41 Live Yeast used for fermenting grapes = wine, grains = beer Yeast Extracts Eduard Buchner demonstrated fermentation does not require living cells Showed enzymes promote chemical reactions Began the field of biochemistry and the study of metabolism

42 The Golden Age of Microbiology Q3- What Causes Disease? Pasteur developed germ theory of disease (microbes cause disease) Now applies to infectious diseases only Robert Koch developed etiology (study of causative agents of disease) also developed experimental microbiology

43 The Golden Age of Microbiology Koch also developed experimental microbiology Simple staining techniques Use of Petri dishes Techniques to transfer bacteria Bacteria as distinct species

44 Figure 1.16 Bacterial colonies on a solid surface (agar). Bacterium 5 Bacterium 6 Bacterium 7 Bacterium 8 Bacterium 4 Bacterium 3 Bacterium 2 Bacterium 1 Bacterium 9 Bacterium 10 Bacterium 11 Bacterium 12 CFU = Colony Forming Unit

45 The Golden Age of Microbiology What Causes Disease? Koch's 4 postulates 1) Suspected causative agent must be found in every case of the disease and be absent from healthy hosts 2) Agent must be isolated and grown outside the host 3) When agent is introduced into a healthy, susceptible host, the host must get the disease 4) Same agent must be found in the diseased experimental host

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47 How Can We Prevent Infection and Disease? Semmelweis and handwashing Lister's antiseptic technique Nightingale and nursing NOSOCOMIAL Infections Snow infection control and epidemiology Jenner's vaccine field of immunology Ehrlich's "magic bullets" field of chemotherapy

48 Figure 1.19 Some of the many scientific disciplines and applications that arose from the pioneering work of scientists just before and around the time of the Golden Age of Microbiology.

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51 The Modern Age of Microbiology How Do We Defend Against Disease? Serology The study of blood serum Von Behring and Kitasato existence in the blood of chemicals and cells that fight infection Immunology The study of the body's defenses against specific pathogens Chemotherapy Fleming discovered penicillin Domagk discovered sulfa drugs

52 The Modern Age of Microbiology What Role Do Microorganisms Play in the Environment? Recyclers of Nature Recycling of chemicals such as carbon, nitrogen, and sulfur

53 Figure 1.9 We learned in BIOL 1406 ENERGY FLOW Chemicals pass to organisms that eat the plants. Light energy Chemical energy Heat Plants take up chemicals from the soil and air. Recyclers of Nature Chemicals Decomposers return chemicals to the soil.

54 Recycling function can be used for our benefit Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments

55 The Modern Age of Microbiology How Do Genes Work? Microbial genetics Molecular biology Recombinant DNA technology Gene therapy

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57 Figure 1.20 The effects of penicillin on a bacterial "lawn" in a Petri dish. Fungus colony (Penicillium) Zone of inhibition Bacteria (Staphylococcus)