Chapters 1 & 3

Introduction to Microbiology

  • Instructor: Kim Williams

  • Focus areas of the course:

    • Fundamentals: replication, metabolism

    • Various fields of microbiology:

    • Environmental microbiology

    • Food microbiology

    • Biotechnology

    • Medical microbiology

    • Immune system of human hosts

    • Diseases caused by microorganisms affecting humans

Basic Terminology

  • Microbiology:

    • Definition: The study of microbes and microorganisms that are typically too small to see without magnification.

    • Examples of microorganisms include:

    • Bacteria

    • Viruses

    • Protozoa

    • Fungi

    • Helminthes (various types of worms)

    • Some microorganisms may be visible at certain life stages without magnification (e.g., adult tapeworm).

  • Normal Microbiota:

    • Definition: Microbes residing on and in the human body which are beneficial.

    • Functions: Protect against illnesses.

    • Opportunistic Infection:

    • Occurs when normal microbiota balance is disrupted, allowing harmful members to thrive and cause disease.

  • Pathogen: A disease-causing microbe.

    • Infectious Disease: When a pathogen infects a susceptible host.

  • Aerobic vs. Anaerobic:

    • Aerobic: Microbes that live in an environment with oxygen.

    • Anaerobic: Microbes that live in environments without oxygen.

    • Facultative Anaerobe: Can tolerate reduced oxygen.

    • Obligate Anaerobe: Must live without oxygen.

    • Obligate Aerobe: Must live with oxygen.

Nomenclature and Classification

  • Scientific naming:

    • Comprises two parts: Genus and Species.

    • Example: Staphylococcus aureus

    • Genus: Staphylococcus (capitalized)

    • Species: aureus (lowercase)

    • Formatting: Scientific names are italicized or underlined.

Applications of Microbiology

  • Medical Microbiology: Investigating diseases.

  • Industrial Microbiology: Production of vaccines and antibiotics.

  • Environmental Microbiology: Example includes bioremediation (use of microorganisms to clean toxic sites).

Fields of Study in Microbiology

  • Bacteriology: Study of bacteria.

  • Mycology: Study of fungi.

  • Virology: Study of viruses.

  • Parasitology: Study of parasites (including helminthes).

Historical Scientific Discoveries in Microbiology

  • 1665: Robert Hooke coined the term "cells" while viewing plant cell compartments, leading to the cell theory.

  • 1673: Anton van Leeuwenhoek discovered motile microbes, studying organisms like Giardia.

  • 1861: Louis Pasteur disproved the theory of spontaneous generation:

    • Original theory claimed non-living could spontaneously produce living.

    • Developed the theory of biogenesis, stating living things reproduce living entities.

    • Disproved spontaneous generation using the swan necked flask:

    • Flasks allowed air circulation but trapped microorganisms in the curved dip of the glass.

    • Demonstrated nutrient broth remained sterile when air exposure was regulated.

Contributions of Louis Pasteur

  • Fermentation and Pasteurization: Techniques developed.

  • Germ Theory of Disease: Established the link between microorganisms and diseases, leading to immunization and antibiotic development.

Microscopy Techniques

  • Compound Light Microscope:

    • Basic type using white light; stains enhance visualization.

  • Phase Contrast Microscope:

    • Views internal structures of living cells; uses light diffraction.

  • Fluorescent Microscope:

    • Requires tagging specimens with fluorochromes, visualized using UV light.

  • Confocal Microscope:

    • Provides 3D images using fluorochrome visualization.

  • Electron Microscope:

    • Employs beams of electrons for visualization; features electromagnetic lenses.

  • Scanned Probe Microscope:

    • Advanced; uses electric current to examine specimens, revealing molecular and chemical properties.