Introduction To Microbiology Lecture 1 PDF

8/23/2024 I. Introduction to Microbiology MTN Cabasan 1 Outline: 1. Scope of Microbiology 2. History and Recent Developments in Microbiology 3. Microorganisms Impact to Life 4. Careers available to Microbiologists 2...

8/23/2024 I. Introduction to Microbiology MTN Cabasan 1 Outline: 1. Scope of Microbiology 2. History and Recent Developments in Microbiology 3. Microorganisms Impact to Life 4. Careers available to Microbiologists 2 1  8/23/2024 Objectives: 1) Discuss the scope of Microbiology 2) Trace the development of microbiology as a science 3) Recognize the contributions of scientists in the development of microbiology as a science 4) List several ways in which microorganisms affect human lives 5) Identify careers available to trained microbiologists 3 4 2  8/23/2024 5 Microbiology the study of organisms and agents too small to be seen clearly by the unaided eye—microorganisms 6 3  8/23/2024 7 Give some examples of the kind of information you think can be provided by microscopic observations of microorganisms. 8 4  8/23/2024 3 domains and the microorganisms placed in them: 9 1) Bacteria - procaryotes that are usually single-celled organisms. - Most have cell walls that contain the structural molecule peptidoglycan. 10 5  8/23/2024 11 2) Archaea - procaryotes that lack peptidoglycan in their cell walls and have unique membrane lipids. - Some have unusual metabolic characteristics [methanogens - generate methane gas] - Often live in extreme environments - Mostly non-pathogenic 12 6  8/23/2024 3) Eucarya - includes microorganisms classified as protists or fungi. Protists are generally larger than procaryotes and include unicellular algae, protozoa, slime molds, and water molds -Algae are photosynthetic protists; cyanobacteria produce about 75% of the planet’s oxygen; foundation of aquatic food chains 13. Protists are generally larger than procaryotes and include unicellular algae, protozoa, slime molds, and water molds -Protozoa - unicellular, animal-like protists that are usually motile - Slime molds - protists that are like protozoa in one stage of their life cycle, but are like fungi in another. - Water molds - found in the surface water of freshwater sources and moist soil. They feed on decaying vegetation (logs and mulch); some infect plants 14 7  8/23/2024 3) Eucarya - includes microorganisms classified as protists or fungi. Fungi: -unicellular forms (yeasts), molds and mushrooms (form thin, threadlike structures –hyphae). - absorb nutrients from environment – use organic molecules as a source of carbon and energy. 15 16 8  8/23/2024 17 The Discovery of Microorganisms Microbiology began with the microscope Robert Hooke (1635–1703): the first to describe microbes Illustrated the fruiting structures of Antoni van Leeuwenhoek (1632–1723): the first to describe bacteria Further progress required development of more powerful microscopes 18 9  8/23/2024 19 Antoni van Leeuwenhoek (1632–1723) 20 10  8/23/2024 Some Important Events in the Development of Microbiology (1546–1899). Milestones in microbiology are marked in red; other historical events are in black 21 Some Important Events in the Development of Microbiology (1900–1980) Milestones in microbiology are marked in red; other historical events are in black 22 11  8/23/2024 Some Important Events in the Development of Microbiology (1981–2005) Milestones in microbiology are marked in red; other historical events are in black 23 The Conflict Over Spontaneous Generation Spontaneous Generation—that living organisms could develop from nonliving matter Francesco Redi (1626–1697), carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. John Needham (1713–1781), experiments on spontaneous generation; boiled mutton broth and then tightly stoppered the flasks. Eventually many of the flasks became cloudy and contained microorganisms 24 12  8/23/2024 The Conflict Over Spontaneous Generation Lazzaro Spallanzani (1729–1799) improved on Needham’s experimental design by first sealing glass flasks that contained water and seeds. If the sealed flasks were placed in boiling water for 3/4 of an hour, no growth took place as long as the flasks remained sealed. Louis Pasteur (1822–1895) first filtered air through cotton and found that objects resembling plant spores had been trapped. If a piece of the cotton was placed in sterile medium after air had been filtered through it, microbial growth occurred. 25 The Conflict Over Spontaneous Generation John Tyndall (1820–1893) dealt a final blow to spontaneous generation in 1877; demonstrated that dust did indeed carry germs, and that if dust was absent, broth remained sterile even if directly exposed to air; provided evidence for the existence of exceptionally heat-resistant forms of bacteria. Ferdinand Cohn (1828–1898) discovered the existence of heat-resistant bacterial endospores. 26 13  8/23/2024 The Golden Age of Microbiology Agostino Bassi (1773–1856) first showed a microorganism could cause disease M. J. Berkeley (1845) proved that the great Potato Blight of Ireland was caused by a water mold Joseph Lister (1827–1912) prevention of wound infections; developed a system of antiseptic surgery designed to prevent microorganisms from entering wounds; Instruments were heat sterilized, and phenol was used on surgical dressings and at times sprayed over the surgical area. 27 The Golden Age of Microbiology Robert Koch (1843–1910) - first direct demonstration of the role of bacteria in causing disease from the study of anthrax; His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch’s postulates 28 14  8/23/2024 29 The Impact of Microorganisms on Humans Microorganisms can be both beneficial and harmful to humans Emphasis is typically on harmful microorganisms (infectious disease agents, or pathogens) Many more microorganisms are beneficial than are harmful Microorganisms as disease agents Control of infectious disease during last century 30 15  8/23/2024 The Impact of Microorganisms on Humans Microorganisms and the human gastrointestinal (GI) tract High numbers of microorganisms occur in colon and oral cavity Positive impacts Synthesize vitamins and other nutrients Compete with pathogens for space and resources 31 The Impact of Microorganisms on Foods Negative impacts Microorganisms can cause food spoilage; for many foods, methods of preservation are needed Positive impacts Microbial transformations (typically fermentations) yield Dairy products (e.g., cheeses, yogurt, buttermilk) Other food products (e.g., sauerkraut, pickles, leavened breads, beer) 32 16  8/23/2024 The Impact of Microorganisms on Agriculture Many aspects of agriculture depend on microbial activities Positive impacts Nitrogen-fixing bacteria Cellulose-degrading microbes in the rumen Regeneration of nutrients in soil and water Negative impacts Diseases in plants and animals 33 The Impact of Microorganisms on energy, and the environment The role of microbes in production of biofuels For example, methane, ethanol, hydrogen The role of microbes in cleaning up pollutants (bioremediation) 34 17  8/23/2024 Modern Microbiology and Genomics In the 20th century, microbiology developed in two distinct directions: Applied and Basic Molecular microbiology Fueled by the genomics revolution 35 Modern Microbiology and Genomics Major subdisciplines of applied microbiology Medical microbiology: infectious diseases Immunology: immune system Agricultural microbiology: microbes associated with soil Industrial microbiology: production of antibiotics, alcohols, and other chemicals Aquatic microbiology: water, wastewater, and drinking water Biotechnology: products of genetically engineered microorganisms 36 18  8/23/2024 Modern Microbiology and Genomics Basic science subdisciplines in microbiology Microbial systematics The science of grouping and classifying microorganisms Microbial physiology Study of the nutrients that microbes require for metabolism and growth and the products that microorganisms generate Microbial ecology Study of microbial diversity and activity in natural habitats 37 1.10 Modern Microbiology and Genomics Basic science subdisciplines in microbiology Microbial biochemistry Study of microbial enzymes and chemical reactions Bacterial genetics Study of heredity and variation in bacteria Virology Study of viruses 38 19  8/23/2024 Modern Microbiology and Genomics Molecular microbiology Genomics: study of all of the genetic material (DNA) in living cells Transcriptomics: study of RNA patterns Proteomics: study of all the proteins produced by cell(s) Metabolomics: study of metabolic expression in cells 39 20