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Introduction to General Microbiology

Introduction to General Microbiology

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Introduction to General Microbiology

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  1. Introduction to General Microbiology Instructor: Laura Hunt, PhD Time: TTHR 8-9:20am

  2. Why is microbiology interesting? • Microbes can be harmful but are a necessary part of our lives CNN: “Superbug succeeds by blowing up defender cells, scientists learn” Nov 2007

  3. What you will get out of this class: • A general introduction to basic concepts and principles of microbiology • There is a lot of material to cover but thankfully it is interesting and applicable

  4. The Importance of Microorganisms • The emergence of higher life forms • Biogeochemical cycling • Huge diversity and physiological capacities • Relationships with higher organisms

  5. What does microbiology refer to? • Microbiology is the study of microorganisms, which can be unicellular or cell-cluster microscopic organisms • This includes eukaryotes: fungi and protists AND prokaryotes: bacteria and certain algae • Viruses, though not strictly classed as living organisms, are also studied. • Microbiology is a broad term which includes many branches including virology, mycology, parasitology and others.

  6. Microorganisms as cells • Cell is fundamental unit of life • Compartmentalized • Dynamic systems • Cells constantly communicate and exchange materials with their environment

  7. Cell Chemistryand Key Structures • Four main components (macromolecules): • Proteins • Nucleic acids • Lipids • Polysaccharides • Key structures: • Cytoplasmic membrane • Cytoplasm • Nucleus

  8. Characteristics of Living Systems

  9. Cells as Machines andas Coding Devices

  10. The First Cells: when/where did the first cell come from a non cell?? • Your just a bag of carbon, oxygen, and hydrogen • The RNA world • Naked RNA are agents of catalysis and coding • First self replicating entity had at least two properties: • 1. Means of obtaining energy • 2. Form of heredity • More in Ch 11

  11. Microorganisms and Their Natural Environments • Cells live in assemblages called populations • Habitat: location in the environment where microbial population lives • Microbial communities: • Where populations live and interact with other populations • Study of microorganisms in their natural habitat is called microbial ecology

  12. The Effect of Organisms on Each Other and on Their Habitats • Populations interact in various ways that can be both harmful and beneficial • Interaction between populations and with physical/chemical environment

  13. The Extent of Microbial Life • Reservoirs of essential nutrients for life • Total carbon equals that of all plants on earth • Prokaryotes comprise the major portion of the Earth’s total biomass: 5 X 1030 cells • Most prokaryotes lie underground in oceanic and terrestrial subsurfaces

  14. 1.4 The Impact of Microorganisms on Humans • Microorganisms as disease agents • Agriculture • Food • Energy and the Environment • The Future: biotech

  15. Important in C,N,S cycle • Convert elements to a form that is readily accessible to plants

  16. Negatives: Food spoilage and food borne diseases • E.coli in spinach

  17. Energy of the Future?? • Microbial fuel cells • Geobacter sp. are of interest because of their novel electron transfer capabilities • Obtain energy from iron oxides • Can transfer electrons to the surface of electrodes • Use “nanowires” to shunt electrons produced during metabolic reactions onto the surface of mineral grains in the soil, to be taken up by metal ions

  18. “The role of the infinitely small in nature is infinitely large” --Louis Pasteur

  19. The birth of microbiology: Pathways of discovery • Slow to develop • Two events: • Invention of the microscope • Spontaneous generation controversy • The Historical Roots of Microbiology: Hooke, van Leeuwenhoek, and Cohn

  20. Early Microscopy • Microscopes were crude, and lacked resolution even though they were compounding. • Some descriptions of bacteria, but very poorly seen • Yet, considering the tools many discoveries were made

  21. Robert Hooke • Described fruiting structures of molds in 1665 • First person to describe microorganisms

  22. Antoni van Leeuwenhoek • Dutch draper and amateur microscope builder • Contemporary of Robert Hooke • First person to observe bacteria in 1676 • “wee animalcules”

  23. Slow growth • After initial discovery of tiny organisms, the field was slow to develop for the next 150 yrs. • Two things became focus as the field moved from the mid to late 19th century • Spontaneous generation • Nature of infectious diseases

  24. Ferdinand Cohn (1828-1898): Science of Bacteriology • Contemporary of Koch and Pastuer • A botanist by trade • Discovered endospores • Laid groundwork for bacterial classification • Sterilization techniques • Founded a major scientific journal

  25. Cohn cont. • Identified sulfur bacterium Beggiatoa mirabilis • Became interested in heat resistant bacterium • Led him to discover Bacillus genus • Described entire life cycle • (vegetative cell- endospore-vegetative cell) • Heat did not kill the endospore

  26. Louis Pasteur (1822-1895) • French microbiologist and chemist • Multi-faceted career

  27. Pasteur and the Downfall of Spontaneous Generation • Ancient belief that organisms arise from nonliving materials • Louis Pasteur was a major opponent to spontaneous generation • Pasteur showed that microorganisms present in air resembled those on putrefying materials • Showed that if you sterilized you would not have purification

  28. Pasteur’s Experiment • In 1864, he crushed spontaneous generation • Pasteur used a swan necked flask for his experiment, now called a Pasteur flask • Simple experiment ended the controversy

  29. Pasteur and Vaccination • Discovered that attenuated strains would provide protection against disease • Made discovery with chickens and cholera • Helped solidify the concept of germ theory of disease

  30. Pasteur and Rabies Vaccine • Known as the man who invented the rabies vaccine • “Benefactor of Humanity” • First exp were on dogs • Then, July 6, 1885 tried vaccine on Joesph Miester, a boy bitten by a rabid dog

  31. Pasteur Institute: 120yrs of discoveries • Diptheria • Plague • Immunology • Tuberculosis • Sulfamides • Molecular biology • AIDS

  32. Pasteur’s main contributions • Instituting changes in hospital/medical practices to minimize the spread of disease by microbes or germs • Coined the term “vaccine” --from the Latin vacca, meaning “cow” • Weak forms of disease could be used as an immunization against stronger forms • Rabies was transmitted by viruses too small to be seen under the microscopes of the time, introducing the medical world to the concept of viruses.

  33. Robert Koch and the Germ Theory of Disease: The Development of Koch’s Postulates • Major contributions: • Discovered anthrax • Discovered the bacterium that causes tuberculosis and chlorea • Koch’s postulates • Developed based on experiments with anthrax in mice • He took experiment one step further and showed that even after many transfers in culture, the bacteria could still cause disease

  34. 1.2 Koch’s Postulates