Intro to micro

Introduction to Microbiology

  • Microbiology is the study of microscopic organisms, which include bacteria, archaea, fungi, protozoa, algae, viruses, and parasites.

Microbes

  • Definition: Microbes are organisms too small to be seen with the unaided eye.

  • Types of microbes include:

    • Bacteria

    • Archaea

    • Fungi

    • Protozoa

    • Algae

    • Viruses

    • Parasites

Microbes Relevance to You

  • Health Implications:

    • Some microbes are pathogenic, causing diseases.

  • Environmental Roles:

    • Decompose organic waste, playing a crucial role in nutrient recycling.

    • Generate oxygen through photosynthesis.

  • Food Production:

    • Used in the production of fermented foods such as cheese and bread.

  • Medical Benefits:

    • Produce antibiotics used to combat bacterial infections.

    • Source of probiotics, which promote gut health.

    • Enhance plant growth, contributing to agriculture.

Studying Microbes

  • Studying microbes enables scientists to:

    • Control food spoilage and enhance food safety.

    • Control infectious diseases through better management and treatment strategies.

    • Gain insights into disease transmission pathways.

    • Understand cellular functions, including metabolism and genetics.

    • Explore molecular pathways that underpin biological processes.

Microbes: A Part of You

  • Microbiome: The community of microbes living on and in a host organism.

    • An adult human has approximately 30 trillion body cells along with an additional 40 trillion bacterial cells.

    • The microbiome plays a significant role in maintaining health and controlling the growth of pathogens.

  • Normal Microbiota: All the microbes that exist in a healthy individual, crucial for various bodily functions.

Prokaryotes

  • Characteristics:

    • Known as "prenucleus" organisms.

    • Lack membrane-bound organelles.

    • Examples include:

    • Bacteria: Have a cell wall composed of peptidoglycan.

    • Archaea: Have a cell wall made of pseudomurein.

    • Reproduce by binary fission.

    • Contain a single circular unpaired chromosome that is free-floating in the cytoplasm.

Eukaryotes

  • Characteristics:

    • Possess a true nucleus containing genetic material.

    • Have membrane-bound organelles that perform specific functions within the cell.

    • Cell walls are typically made of polysaccharides.

    • Reproduce through mitosis.

    • Contain linear paired chromosomes enclosed within a nuclear membrane.

Naming and Classifying Organisms

  • Historical Context: Carolus Linnaeus established the system of scientific nomenclature in 1735, providing a structured method for naming species.

  • Components of Species Names: Every species name consists of:

    • Genus: The first part of the name, which is capitalized.

    • Specific Epithet: The second part of the name, which is in lowercase.

Nomenclature: Rules for Species Name

  • Formatting Requirements:

    • Scientific names must be italicized or underlined.

    • Genus name begins with a capital letter while the specific epithet is all lowercase.

    • Names are Latinized for use in international scientific literature, allowing for universal understanding.

    • Names can be descriptive of features or honor a person.

Examples of Species Names

  • Examples of scientific names include:

    • Escherichia coli

    • Staphylococcus aureus

Nomenclature: Additional Rules when Writing

  • After the initial use, scientific names can be abbreviated:

    • Use the first letter of the genus followed by a period, plus the full specific epithet.

  • Example:

    • Full names: Escherichia coli and Staphylococcus aureus.

    • Abbreviated: E. coli grows in the gastrointestinal tract, while S. aureus is commonly found on the skin.

Towards a Natural System of Organisms

  • Proposed Taxa: Carl R. Woese, Otto Kandler, and Mark L. Wheelis proposed a new taxonomy, organizing life into three domains:

    • Bacteria

    • Archaea

    • Eukarya

    • Their work emphasizes molecular data over classical phenotype-based classification.

Taxonomy: Domain

  • The current taxonomic system divides life into three domains:

    • Bacteria

    • Archaea

    • Eukarya

Taxonomical Hierarchy

  • The hierarchical classification includes:

    • Species: Basic unit of classification.

    • Genus: Grouping of closely related species; example: Escherichia.

    • Family: Ends with 'aceae'; incorporates the genus name; example: Enterobacteriaceae.

    • Order: Ends with 'ales'; includes the family name; example: Enterobacterales.

    • Class: Example: Gamaproteobacteria.

    • Phylum: Typically ends in 'ota'; example: Pseudomonadota.

    • Kingdom: Typically ends in 'ati'; example: Pseudomonadati.

    • Domain: Highest taxonomic rank; example: Bacteria.

Additional Examples of Taxonomy

  • Example Classifications:

    • Bacillus subtilis → Genus: Bacillus, Family: Bacillaceae, Order: Bacillales, Class: Bacilli, Phylum: Bacillota, Kingdom: Bacillati, Domain: Bacteria.

    • Staphylococcus aureus → Genus: Staphylococcus, Family: Staphylococcaceae, Order: Bacillales, Class: Bacilli, Phylum: Bacillota, Kingdom: Bacillati, Domain: Bacteria.