Micro CH1

• Microbe/microorganism


  A living organism that requires a microscope to be seen

  
• Microbial cells


  • Range in size from millimeters (mm) to 0.2 micrometer (µm)
  • Viruses may be ten times smaller
• Some microbes consist of a single cell
• Each microbe contains in its genome the capacity to reproduce its own kind
• Microbiology


  The study of organisms too small to be seen without magnification
• To figure what a microbe is, we have to use tools such as microscopes

  
• Types of Microorganisms


  • Bacteria
  • Protozoa
  • Fungi
  • Helminths (worms)
  • Algae
  • Viruses
• Microbial communities


  • Example: biofilms
• Viruses


  • Example: mimivirus
• Contradictions to definition of microbe
• Microbes in Our Lives


  • A few are pathogenic (disease-producing)
  • Decompose organic waste
  • Generate oxygen by photosynthesis
  • Produce chemical products such as ethanol, acetone, and vitamins
  • Produce fermented foods such as vinegar, cheese, and bread
  • Produce products used in manufacturing (e.g., cellulase) and disease treatment (e.g., insulin)
• Microbes include members of the three domains of life
• Prokaryotes


  Simple cells, pre-nucleus
• Eukaryotes


  Complex cells, true nucleus
• Viruses


  • Acellular, parasitic particles composed of a nucleic acid and protein
• Prokaryote


  • Microscopic, unicellular organisms, lack nuclei and membrane-bound organelles
• Eukaryote


  • Unicellular (microscopic) and multicellular, have nucleus and membrane-bound organelles
• The flow of energy and food through the earth's ecosystems
• Photosynthesis


  Light fueled conversion of carbon dioxide to organic material
• Decomposition


  Breakdown of dead matter and wastes into simple compounds
• Lifestyles of Microorganisms


  • Majority live a free existence, are relatively harmless and often beneficial
  • Some microorganisms have close associations with other organisms
  • Parasites live on or in the body of another organism called the host and it damages the host
• Human use of microorganisms


  • Biotechnology: Production of foods, drugs, and vaccines using living organisms
  • Genetic engineering: Manipulating the genes of organisms to make new products
  • Bioremediation: Using living organisms to remedy an environmental problem
• Microbes shape human history
• Yeasts and bacteria


  • Foods and beverages
• "Rock-eating" bacteria


  • Lithotrophs enabled mining of metals
• Unfortunately, they also consume stones of ancient monuments
• Microbes have shaped human culture since our earliest civilizations
• Microbial diseases that have profoundly affected human demographics and cultural practices


  • 14th century: bubonic plague caused by Yersinia pestis
  • 19th century: tuberculosis caused by Mycobacterium tuberculosis
  • 20th century: acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV)
  • 21st century: Covid-19 caused by SARS-CoV-2
• Throughout history, more soldiers have died of microbial infections than of wounds in battle
• The significance of disease in warfare was first recognized by the British nurse Florence Nightingale (1820–1910)
• She founded the science of medical statistics
• Pathogens


  Microbes that do harm
• Nearly 2,000 different microbes cause diseases
• 10 billion new infections/year worldwide
• 13 million deaths from infections/year worldwide
• Prominent discoveries in the historical foundations of microbiology


  • Microscopy
  • Scientific method
  • Development of medical microbiology (germ theory of diseases)
  • Microbiology techniques
• Robert Hooke (1635–1703)


  • Built the first compound microscope
  • Used it to observe mold
  • Published Micrographia, the first manuscript that illustrated objects under the microscope
  • Coined the term "cell"
• Antonie van Leeuwenhoek (1632-1723)


  • Dutch linen merchant
  • First to observe living microbes
  • Single-lens magnified up to 300X
  • Called them animalcules (small animals)
• Spontaneous generation (Abiogenesis)


  Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter
• Spontaneous generation


  • Flies from manure, maggots from decaying meat