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Exploring Microorganisms: Introduction to General Microbiology

Delve into the world of microbiology, learning about different types of microbes, biological classification, and the history of microbiology pioneers. Understand the classification systems, binomial nomenclature, and the characteristics of various microorganisms such as bacteria, viruses, fungi, protists, algae, and helminths. Discover the structure and physiology of prokaryotes, eukaryotes, and acellular viruses. Learn about the diversity and characteristics of organisms studied in microbiology and how they impact various environments.

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Exploring Microorganisms: Introduction to General Microbiology

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  1. Introduction and Overview of General Microbiology Lecture 1 What is Microbiology?

  2. In Microbiology- We Study “Microbes” What are microbes? Micro- means small… By definition, we study small organisms… those that we cannot see with the naked eye…. (limit of resolution of eye = 0.2 mm)

  3. Biological Classification: The Five Kingdoms (Whittaker) (based on morphological features) Uni or multicellular Eukaryotic Eukaryotic Unicellular Bacteria Archaea Prokaryotic Unicellular

  4. Eukarya (Eu)Bacteria Archaea (Make up other 4 Kingdoms) (Makes up 1 Kingdom – Monera) Biological Classification Today – 3 Domain (Superkingdoms) System (Woese) (Based mainly on a gene sequence (DNA))

  5. Binomial Nomenclature • Carolus (Carl) Linnaeus – 1750’s – probably not the first person to do this but certainly made it popular and acceptable Homo sapiens – Homo is the genus (pl. genera), name can only be used once… always capitalized sapiens – species epithet… never capitalized and can be used many times Both the genus and species epithet make up the “species” name

  6. What organisms do Microbes include? • 1) Bacteria (Prokaryotes) • 2) Viruses • 3) Fungi (yeasts, molds) • 4) Protista (protozoans) • 5) Algae • 6) Helminths

  7. 2) Protista Eukaryotic Most Unicellular 1) Bacteria (Eu)bacteria Archaea Archeabacteria Prokaryote Unicellular 3) Fungi Eukaryotic Uni- or multicellular

  8. 4) Helminths Multicellular eukaryotes Roundworms Flatworms 5) Viruses Alive? Organisms? Neither prokaryotic or Eukaryotic… 6)Algae Many are microscopic We are really talking about Eukaryotic Types

  9. Types of Microorganisms • Prokaryotes = Bacteria • Unicellular organisms • No compartmentalization • No organelles • No nucleus • Cell wall • All reproduce by binary fission or budding • Ribosomes • Plasma membrane • Circular DNA chromosome • Plasmids Small in size 1000 X magnification 200 nm to 1 mm Tremendous diversity

  10. Prokaryotes 2 Main Groups More in Chapter 4 1) Bacteria or Eubacteria (“True” Bacteria) Non-archaea prokaryotes Most have Peptidoglycan in the cell wall 2) Archaea Possibly Ancient (hence the name) Different structure & physiologies Harsh environments Extremophiles No peptidoglycan in their cell wall

  11. Main Types of Bacteria • Four main types - based on morphology (shape) coccus (sphere-shaped) bacillus (rod-shaped) (pl. cocci) strep- staph- and diplo- (pl. bacilli) (sub-categories do exist (cocco-bacilli, vibrios)) spirillum (pl. spirilla) helical – flattened “s”-shaped non-flexible cell wall spirochete (corkscrew shaped) (flexible cell wall)

  12. Protista • Eukaryotic microbes • Most are unicellular • Have no cell wall - only plasma membrane • May have pellicle • Most are motile - distinguished by type of motility • Pseudopods - cytoplasmic extensions, “false foot” • (amoebas) • Flagella - “whip like” propellers (flagellates) • Cilia - short hair-like structures coating entire surface • (ciliates)

  13. Fungi • Eukaryotic organisms, extensive subcellular • compartmentalization • Can be single or multicellular organisms (yeasts mold hyphae) • Cell wall is composed of chitin • Can replicate either asexually (binary fission) or • sexually (mating) • Obtain nutrients from surroundings • Parasites or saprophytes

  14. Types of Fungi Multi-cellular (Molds) Penicillium Unicellular (Yeast) Saccharomyces cerevisiae Multi-cellular Mushrooms

  15. Algae • Can be either unicellular or multicellular • Photosynthetic eukaryotes • Cellulose cell wall • Exist in many environments (water and land) • Photoautotrophs • Consumed by animals as food

  16. Viruses • Acellular • Simple virus • Capsid (protein) • Nucleic acid (DNA or RNA) Electron microscope 10 nm – 200 nm

  17. History of Microbiology • Two major pioneers… • Antonie van Leeuwenwoek – • first to visualize bacteria- created the “simple” microscope (1660’s) • Robert Hooke – devised the “compound” microscope (1660’s) and coined the term “cell” • This turned out to be the beginning of the end of “spontaneous generation” (superstition)

  18. Spontaneous Generation • Life arising from dead matter • Maggots would “appear” on spoiled meat • Fungi, insects, millipedes, and snakes found in rotten logs • Was believed life spontaneously generated from the • decomposing food

  19. Several Days Later First Evidence Against “Spontaneous Generation” (life from non-life) Francesco Redi - 1668 Maggots only appeared if flask was open! Spoiled Meat Did not exclude the possibility of spontaneous generation of bacteria

  20. Proponents of Spontaneous Generation Battle Back! • John Needham’s broth experiments - 1745 • Boiled broth was devoid of life • Days later - teeming with microorganisms • Argued that microbes could arise spontaneously from • non-living mater • Lazzaro Spallanzani’s modification - 1765 • Only uncovered broth contained microorganisms • Proponents argued that fresh air was required

  21. The Final Blow to the “Spontaneous Generation” Hypothesis • Louis Pasteur - 1861

  22. Significant Advances in Microbiology • 1864 - Fermentation and Pasteurization - Louis Pasteur • Discovered source of fermentation • Yeast convert sugar to alcohol • Bacteria cause spoiling - convert alcohol to vinegar • Found heating perishables prevented spoiling – kills • bacteria

  23. Significant Advances in Microbiology • 1876 - The Germ Theory of Disease proved correct • Robert Koch developed “Koch’s Postulates” (4) • Anthrax decimating cattle industry • 1) Find evidence of a microbe in all infected individuals • 2) Isolate rod-shaped bacterium from infected individual • 3) Introduce bacterium to healthy individual and get same disease • 4) Can reisolate the same bacterium from diseased individuals

  24. Significant Advances in Microbiology • 1796 - First successful vaccination - Edward Jenner • Smallpox epidemics prevalent • Cowpox caused similar disease in cattle – mild • disease in humans • Jenner found infecting humans with cowpox • protected against smallpox infection • Due to antigenic similarity between two viruses (body recognizes these viruses as the same in some ways)

  25. Significant Advances in Microbiology • 1928 - Discovery of Antibiotics - Alexander Flemming • Plate contaminated with • Penicillium • Zone of inhibition • Killed Streptococcus • Called substance penicillin

  26. Fields of Microbiology • Bacteriology - study of bacteria (includes Bacteria and Archaea) • Mycology - study of fungi • Parasitology - study of parasitic protozoa and worms • Virology - study of viruses • Immunology - study of the host response to infection • Protozoology – general study of protozoa • Algalogy – study of algae (for some might include cyanobacteria)

  27. Lecture 1 questions?

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