Microbiology Overview

Microbiology

• Study of organisms too small to see without magnification
• Originated with microscope invention
• Microorganisms include: Bacteria, Viruses, Fungi, Protozoa, Helminths (worms), Algae, Prions

Branches of Study Within Microbiology

• Immunology
• Public health microbiology and epidemiology
• Food, dairy, and aquatic microbiology
• Biotechnology
• Genetic engineering and recombinant DNA technology
• Manipulating genes

Microbes and Their Roles

• Involved in nutrient production and energy flow
• Essential for decomposition
• Used in biotechnology for food, drug, and vaccine production
• Play a role in genetic engineering
• Contribute to bioremediation and fight against infectious diseases

Classification of Microorganisms (Protists)

I. Cellular

• Prokaryotes: Lack a true nucleus (pro=before or early; karyon=nucleus). Include Archaea, bacteria, and blue-green algae.
• Eukaryotes: Possess a true nucleus. Examples include algae (excluding blue-green), fungi, and protozoans.

II. Non-Cellular

• Viruses, viroids, prions

Taxonomy

• Formal system for organizing, classifying, and naming living organisms
• Bacteria: Prokaryotic, unicellular organisms
• Archaea: Prokaryotic, unicellular organisms that thrive in highly salty or extreme temperature environments
• Algae: Eukaryotic, unicellular or multicellular organisms, often performing photosynthesis
• Fungi: Eukaryotic, unicellular or multicellular organisms
• Protozoa: Eukaryotic, unicellular or multicellular organisms
• Viruses: Noncellular, only visible via electron microscope; consist of a nucleic acid (NA) surrounded by a protein coat

Bacterial Life Cycle

• Vegetative Form: Metabolically active, growing, and multiplying; capable of causing infection
• Spore Form: Inert, resting, and non-multiplying; highly resistant and capable of surviving for years under unfavorable conditions.

Cytoplasmic Organelles

• Mitochondria: Long fluid-filled sacs; powerhouses of the cell, involved in ATP production.
• Ribosomes: Small granules of RNA; crucial in protein synthesis.
• Endoplasmic Reticulum (ER): Netlike system of sacs; involved in protein synthesis (rough ER) and lipid synthesis (smooth ER).
• Golgi Apparatus: Flat sacs connected to the ER; involved in packaging and shipping of cellular products.
• Lysosomes: Sacs containing digestive enzymes.
• Centrioles: Two rods at right angles; crucial in cell division.
• Cilia: Short, numerous hair-like structures used for movement.
• Flagella: Long, few structures used for movement.
• Chloroplasts: Found in algae and plant cells; convert light energy into chemical energy through photosynthesis.

Defense Mechanisms Against Infection

• Nonspecific Mechanisms: Act against all harmful agents. Provide nonspecific resistance (e.g. skin, fluids, complements).
• Specific Mechanisms: Targeted against certain pathogens (e.g., immune cells). Provide specific resistance to pathogens and contribute to an immune response. Resistance is often denoted as immunity, whereas lack of resistance is called susceptibility; virulence measures pathogenicity or disease-causing power of a specific microbe.

Modes of Transmission

• Contact: Direct physical contact or through indirect contact (fomites).
• Droplet: Transmission of infectious agents via respiratory droplets.
• Airborne: Transmission of organisms traveling more than a meter.
• Waterborne & Foodborne: Transmission via contaminated water or food.
• Vector-borne: Transmission via animals or arthropods.

Applied Microbiology

• Wide range of applications in different fields, like food production, treatment of water, pharmaceuticals, agriculture, environmental remediation, forensic science, and energy production.