Introduction to Microbiology PDF

1. Introduction to Microbiology Dr. Kelly Brathwaite  General information Office hours: Wednesdays 10 am-12 pm Office location: Biology Extension Contact: [email protected]  Courtesies Be respectful to others Be on time Pay attent...

1. Introduction to Microbiology Dr. Kelly Brathwaite  General information Office hours: Wednesdays 10 am-12 pm Office location: Biology Extension Contact: [email protected]  Courtesies Be respectful to others Be on time Pay attention If you can’t pay attention…do not disrupt others Switch off/Silence your cell phones  Course overview This course will cover the basic principles of Microbiology including cell structure/function, microbial diversity, microbial metabolism, control of microorganisms through the use of physical and chemical agents (antibiotics), and the importance of microorganisms in human activities.  Prerequisite courses for MICR2260 All students MUST have completed the following: BIOL1020-Diversity of Life I (BIOL1051-Biodiversity I) & BIOC1015-Introduction to Biochemistry (or BIOC1351- Introductory Biochemistry)  Recommended Textbook Madigan, MT, Bender, KS, Buckley, DH, Sattley, WM and Stahl, DA. Brock Biology of Microorganisms. 2020. 16th ed. Pearson Benjamin Cummings. (BBM). QR41.2.B77  Course assessment Final theory exam (2 hours) 50% In-course test(s)/assignment(s) 20% Practical report/quizzes/test 30%  Course outline 18 LECTURES 6 TUTORIALS ASSESSMENTS: 2 x IN-COURSE TESTS, FINAL EXAM ------------------------------------------------------------ 6 PRACTICALS ASSESSMENTS: LAB REPORTS, LAB SKILLS, CALCULATIONS, QUIZZES, LAB TEST  Lecture Objectives What is Microbiology? Brief History of Microbiology - Spontaneous Generation - The Germ Theory - van Leeuwenhoek, Louis Pasteur and Robert Koch - Other important historical events But before we get started… MICROORGANISMS  What is Microbiology? The study of very small organisms (microorganisms) that cannot be seen with the naked eye Magnification is needed - MICROSCOPE Exist as free-living single cells or clusters of cells Also includes viruses, which are microscopic but acellular  Major Groups of Microorganisms ❖ Bacteria ❖ Viruses ❖ Fungi (Molds) ❖ Protozoa (uni-cellular) ❖ Helminths (multi-cellular parasites : worms) ❖ Algae (uni-cellular or multicellular) Bacterial cell types Structure of a bacterial cell wall A bacterial cell Types of viruses Types of fungi Comparison of sizes  History Prominent discoveries - Microscopy - Disproval of spontaneous generation - Development of medical microbiology - Microbiological techniques Antonie van Leeuwenhoek (1632-1723) Dutch amateur microscope builder Used extremely simple microscopes of his own construction Reported observations to the Royal Society of London, which published them in 1684 He referred to what he saw as “wee animacules” (from Latin animalculum = "tiny animal") Van Leeuwenhoek’s microscope (Late 1600’s) van Leeuwenhoek’s drawings of bacteria, published in 1684 Two important questions arose in the 19th century: 1. Can living organisms 2. How does an originate from non- infectious disease living material? [The spread from one theory of spontaneous individual to another? generation] The Theory of Spontaneous Generation One of the earliest recorded scholars to communicate this theory to others. “Life arises from non-living material” Dust created fleas, maggots arose from rotting meat, and bread or wheat left in a dark corner produced mice. Aristotle (384–322 BC) Experiments of Francesco Redi (1626-1697)  Disproval of spontaneous generation Food that is allowed to stand for some time in the open became putrefied (spoilt) → microscopic examination found food to contain bacteria French chemist Louis Pasteur was the first to disprove the theory of spontaneous generation. Deduced that cells in the air were constantly being deposited on all objects →if they could be destroyed then the food should not putrefy. Pasteur’s experiment with swan-necked flasks – disproval of spontaneous generation “Life only comes from previously existing life” Louis Pasteur (1822-1895) Accomplishments include: Pasteur flask Pasteur pipette Process of pasteurization Contributed towards development of first vaccines Developed cures for rabies, anthrax, chicken cholera, and silkworm diseases Robert Koch (1843-1910) German physician/medical microbiologist Developed an experimental method to determine whether a particular microorganism is the cause of a disease Built on Pasteur’s work and proved that the bacterium Bacillus anthracis was the cause of anthrax Awarded the 1905 Nobel Prize for his work on tuberculosis  ✓ Derived from Robert Koch's early work on Koch’s infectious diseases (anthrax and postulates tuberculosis). ✓ Attempted to establish a standard for identifying the specific cause of an infectious disease. ✓ Developed to convince novice microbiologists to use more rigorous criteria before claiming a causal relationship between a microorganism and a disease. Harvey et al, 2013 Some of the Normal flora criteria cannot be causing Pathogen may met by many disease cause pathogenic Opportunistic Some subclinical microorganisms pathogens pathogens infection in may cause some Cannot be grown in pure culture in the several individuals vs. lab (in vitro) diseases clinical No animal model infection in available others Ethics Limitations to Koch’s postulates  Limitations to Koch’s Postulates Molecular and genetic evidence may replace and overcome these limitations. Ferdinand Cohn (1828-1898) German botanist known for his studies of algae, bacteria, and fungi. Considered one of the founders of bacteriology. First to classify bacteria into four groups based on shape (sphericals, short rods, threads, and spirals). First to show that Bacillus can change from a vegetative state to an endospore state when subjected to an environment not conducive to the vegetative state. Martinus Beijerinck (1851-1931) Dutch Microbiologist who was recognized as one of the founders of virology and environmental microbiology. Studied bacteria from soil and water eg aerobic nitrogen-fixing soil bacteria (Azotobacter). Studied the tobacco mosaic virus → by using selective filtration techniques was able to determine that viruses(and not bacteria) caused the disease. Developed the principles of enrichment culture.  Summary Early work led the way for scientists to understand the role of microorganisms in infectious disease These principles paved the way for modern day microbiological techniques and medical microbiology https://www.youtube.com/watch?v=uKLrhp4Kw2A Any Questions?