L1 - Introduction to Microbiology

Introduction to Microbiology

• Introduction to Microbiology (2011)

The Role of the Infinitely Small in Nature

• "The role of the infinitely small in nature is infinitely large" - Louis Pasteur (1011)

Lesson Objectives

• Key Learning Goals:

  • What is Microbiology?

  • Why Study Microbiology?

  • First Microorganisms on Earth

  • Earliest Known Infectious Diseases

  • Pioneers in the Science of Microbiology

  • Careers in Microbiology

What is Microbiology?

• Scientific study of certain microscopic and nonliving entities as well as living organisms, collectively referred to as microbes.

• Categories of Microbes:

  • Acellular Microbes: Infectious agents such as viruses and prions.

  • Cellular Microbes: Includes procaryotes (archaea and bacteria) and eucaryotes (algae, fungi, and protozoa).

Microbes

• Pathogens:

  • Disease-causing microbes; only about 3% of known microbes are pathogenic.

• Nonpathogens:

  • Vast majority of microbes, do not cause disease, some beneficial (microbial allies).

• Opportunistic Pathogens:

  • Normally harmless but can cause disease under certain conditions (e.g., weakened immune system).

Importance of Studying Microbiology

• Microbes significantly impact our lives despite their small size. Reasons for studying microbiology include:

  • Indigenous Microflora:

    • Microbes on/in our bodies that outnumber human cells by 10:1, preventing pathogen growth by occupying niches.

  • Photosynthetic Bacteria:

    • Produce oxygen crucial for life; essential for beings that require oxygen.

  • Decomposers/Saprophytes:

    • Involved in decomposition, recycling nutrients into soil.

  • Nitrogen-Fixing Bacteria:

    • Convert atmospheric nitrogen into forms usable by plants.

  • Bioremediation:

    • Utilize microbes to decompose pollutants (e.g., oil spills).

  • Elemental Cycles:

    • Participation in cycles (carbon, nitrogen) beneficial for agriculture.

  • Food Chains:

    • Serve as foundational elements in food webs; phytoplankton and zooplankton.

  • Digestive Aid:

    • Microbes in the digestive tract assist in food digestion and vitamin production.

  • Biotechnology:

    • Utilize microbes in food production, chemicals, and medical applications.

  • Genetic Engineering:

    • Engineering microbes to produce human proteins, aiding medical treatments.

  • Model Organisms:

    • Studying microbes aids in understanding eukaryotic cells; E. coli as a prime example.

  • Diseases:

    • Understanding infectious diseases and microbial intoxications.

Early Microorganisms on Earth

• Earth formed approximately 4.5 billion years ago; earliest fossils (3.5 billion years old) suggest existence of archaea and cyanobacteria.

Earliest Known Infectious Diseases

• Human pathogens have existed for thousands of years, with evidence found in mummies.

• Conditions such as tuberculosis, syphilis, and parasitic worm infections reported.

• Historical records of epidemics:

  • 3180 BC: Egypt's earliest “pestilence.”

  • Impact of diseases throughout different eras, such as bubonic plague.

Pioneers in Microbiology

• Early observations led to significant advances:

  • Development of microscopes, bacterial staining, culturing techniques, etc.

• Anton van Leeuwenhoek:

  • "Father of Microbiology;" first to observe live bacteria, advancing microscopy.

• Louis Pasteur:

  • Discovered principles of fermentation, disproved spontaneous generation.

• Robert Koch:

  • Established germs as causative agents of disease; defined Koch's Postulates.

Careers in Microbiology

• Microbiologists can specialize in various fields:

  • Bacteriologist: Studies bacteria structure and function.

  • Virologist: Studies viruses and genetic engineering effects.

  • Clinical Microbiologist: Diagnoses infectious diseases in humans, supports medical industry.

  • Medical Microbiologist: Focuses on pathogens and disease prevention.

Review Questions

• Define key terms such as pathogen, nonpathogen, opportunistic pathogen.

• Contrast acellular microbes with cellular microorganisms and provide examples.

• Discuss the contributions of Leeuwenhoek, Pasteur, and Koch to microbiology.