Microbiology and Microorganisms

Biology of Microbial Cell

• Biology refers to the study of living organisms, while microbiology studies very small microorganisms or microbes that require a microscope.

Microorganisms (MOs)

• Include bacteria, algae, protozoa, fungi, and viruses
• Viruses are infectious agents or particles
• 3% of microbes are pathogens (disease-causing), while 97% are non-pathogenic
  • 87% of non-pathogens are beneficial and form indigenous microflora or microbiota
  • Microorganisms are ubiquitous (found everywhere)

History of Microbiology

• Antony Van Leeuwenhock discovered "animalcules" (microorganisms) in 1676
• Spontaneous Generation theory believed living organisms arise from decomposing matter
  • Contrasted with Biogenesis, which states life arises from pre-existing life

Contributions of Louis Pasteur

• Showed microbes cause fermentation and spoilage
• Disproved Spontaneous Generation
• Developed aseptic techniques (free from pathogenic microorganisms)

Germ Theory of Disease

• Diseases are transmitted by microbes from a diseased to a healthy person
• Examples: Diphtheria (Corynebacterium diphtheriae) and Tetanus (Clostridium tetani)

Contributions of Robert Koch

• Developed solid growth media
• Introduced pure culture techniques
• Developed simple stain technique
• Developed aseptic lab techniques
• Isolated bacteria as causative agents for Anthrax

Koch's Postulates

• Series of experimental steps to show a specific organism causes a specific disease

Spores and Sterilization

• Ferdinand Cohn discovered and described endospores
• Term "sterile" means complete removal of all life forms, including endospores

Branches of Microbiology

• Basic Microbiology: classifications, metabolism, nutrition, growth, and requirements
• Medical Microbiology: Human pathogens
• Industrial Microbiology: Microorganisms used to obtain industrial products
• Pharmaceutical Microbiology: Production of drugs, enzymes, solvents, and other products
• Agricultural Microbiology: Microorganisms as biofertilizers and biocontrol agents of plant pathogens
• Environmental Microbiology (Microbial Ecology): Microorganisms in pollution, biodegradation, and environmental processes

Learn about microbiology, the study of microorganisms, including bacteria, algae, protozoa, fungi, and viruses, and their characteristics, benefits, and roles in the environment and human health.