MicroBiology

Chapter 01: The Main Themes of Microbiology

Section 1.1 & 1.2: The Scope of Microbiology

  • Learning Outcomes: List the seven types of microorganisms studied in this book.

Major Groups of Microorganisms

  • The major groups of microorganisms include:

    • Bacteria

    • Archaea

    • Fungi

    • Protozoa

    • Viruses

    • Prions

    • Helminths

    • Note: Helminths are not technically microorganisms but are multicellular animals whose mature form is visible to the naked eye.

  • Distinction between cellular and acellular microorganisms:

    • Cellular: Bacteria, Archaea, Eukaryotes (including fungi, protozoa, and helminths)

    • Acellular: Viruses, prions

The Impact of Microbes on Earth

  • Early Life Forms:

    • Soon after the earth was formed, the first ancient cells emerged.

    • Bacteria and archaea developed from these early cells.

    • Eukaryotes appeared more than a billion years later, signaling a significant evolutionary step.

Bacteria Are Ubiquitous

  • Distribution:

    • Bacteria are found in various extreme environments, including:

    • Deep in the earth’s crust

    • Polar ice caps

    • Oceans

    • Inside the bodies of plants and animals

Evolution

  • Definition of Evolution:

    • Evolution is defined as the accumulation of changes that occur in organisms as they adapt to their environments.

  • Theory of Evolution:

    • Documented every day in various environments around the world.

    • Observable phenomena that can be tested scientifically.

    • Refers to a well-studied and established natural phenomenon.

Human Use of Microorganisms

  • Historical Usage:

    • Humans have utilized microorganisms for thousands of years to enhance life and influence civilizations.

    • Examples include:

    • Yeast used for bread, wine, and beer production.

    • Fungi employed in cheese production.

    • Moldy bread historically used in Egypt for wound treatment.

    • Whole viruses or their components used in vaccine development.

Pathogens

  • Definition of Pathogen:

    • A pathogen is any agent, including a virus, bacterium, fungus, protozoan, or helminth, that causes disease.

    • Approximately 2000 different microbes have the potential to cause diseases in humans.

Section 1.5: The General Characteristics of Microorganisms

  • Learning Outcomes: Differentiate among bacteria, archaea, and eukaryotic microorganisms.

General Characteristics of Microorganisms

  • Table 1.1: Relative Sizes of Microorganisms:

    • The size of microorganisms varies significantly, represented in micrometers (µm) and nanometers (nm).

    • Prion: 10 nm

    • Virus: 100 nm

    • Eukaryotic Cell: 1000 nm (1 µm)

    • Bacterium/Archaeon: 1000 – 10,000 nm (1 - 10 µm)

    • Eukaryotes: Fungi, protozoa, helminths

Section 1.6: The Historical Foundations of Microbiology

  • Learning Outcomes: Identify significant historical events in microbiology, including microscopy, germ theory, biogenesis, aseptic techniques, and Koch’s postulates.

Brief History of Microbiology

  • Pasteur's Experiment:

    • Pasteur disproved spontaneous generation through a series of experiments.

    • Key points:

    • Broth was boiled in a flask to sterilize it.

    • When exposed to air without a barrier, microbial growth occurred.

    • In a sterile environment, with the neck intact, microbes were trapped, preventing growth.

Development of the Microscope

  • Robert Hooke:

    • Conducted the first observations of microbes in the 1600s.

  • Antonie van Leeuwenhoek:

    • Created a crude microscope capable of observing threads in fabrics.

    • Made illustrations of microorganisms he referred to as “animalcules” from rainwater and his own dental scrapings.

Establishment of the Scientific Method

  • Scientific Method:

    • A systematic approach employed by scientists to elucidate natural phenomena.

  • Hypothesis:

    • A tentative explanation formulated to account for observed or measured phenomena.

Deductive and Inductive Reasoning

  • Deductive Reasoning Example:

    • Induces a specific action based on a general principle, such as avoiding opening unknown email attachments to prevent virus infections.

  • Inductive Reasoning Example:

    • Three instances of opening unknown attachments led to computer crashes; thus, a conclusion was drawn regarding the risks associated with this action.

Discovery of Spores and Sterilization

  • John Tyndall:

    • Discovered that microbes in dust and air exhibited high heat resistance.

  • Sterility Definition:

    • A sterility status indicates the absence of all life forms, including spores and virus particles.

Development of Aseptic Techniques

  • Robert Koch:

    • Linked specific microorganisms to specific diseases, revolutionizing medical microbiology.

  • Dr. Oliver Wendell Holmes:

    • Observed lower infection rates in mothers birthing at home compared to hospital births.

  • Dr. Ignaz Semmelweis:

    • Showed a correlation between doctors’ hand hygiene and maternal infections, advocating for antiseptic measures.

Further Development of Aseptic Techniques

  • Joseph Lister:

    • Pioneered handwashing and antiseptic sprays in operating rooms.

    • His principles laid the groundwork for modern microbial control protocols.

Discovery of Pathogens and the Germ Theory of Disease

  • Louis Pasteur:

    • Inventor of pasteurization and investigator of infection links to human diseases.

  • Robert Koch:

    • Developed a series of postulates that substantiated the germ theory of disease.

Section 1.7: Naming, Classifying, and Identifying Microorganisms

  • Learning Outcomes: Define nomenclature and correctly write the binomial name for microorganisms.

Binomial System of Nomenclature

  • Definition:

    • The binomial system combines the genus name and the species name.

    • Format:

    • Genus name is capitalized, while the species name starts with a lowercase letter.

    • Both names should be italicized in print or underlined when handwritten.

  • Abbreviation Example:

    • Staphylococcus aureus can be abbreviated to S. aureus if previously stated.

Labeling Plates and Tubes in Lab

  • Essential items to include on lab labels:

    • Name (consider potential initials overlaps)

    • Date

    • Section number

    • Name of organism(s) in correct scientific nomenclature.

Examples of Binomial Nomenclature

  • Common Organisms:

    • Homo sapiens = H. sapiens

    • Canis familiaris = C. familiarius

    • Bacillus megaterium = B. megaterium

    • Staphylococcus aureus = S. aureus

    • Streptococcus mutans = S. mutans

Concept Mapping Introduction

  • Definition:

    • A concept map is a visual representation of a topic, aiding in the organization and processing of information.

  • Basic Components:

    • Boxes or circles representing individual concepts.

    • Connecting lines that link concepts.

  • Software Tools:

    • Lucidchart

    • Cmap Tools

    • Gliffy

Examples of Concept Mapping

  • Example structure illustrating relationships among terms such as microorganisms, organelles, pathogens, etc.

Time to Try Concept Mapping

  • Use terms from the chapter to create personalized concept maps. Example terms:

    • Microorganisms, Organelles, Protozoa, Bacteria, Prokaryote, Pathogen, Fungi, Helminths, Eukaryote, Viruses.

Evolutionary Time Line

  • Graph Overview:

    • First cells existed 3.5 billion years ago, leading to the emergence of eukaryotes, archaea, and bacteria approximately 2.9 billion years ago, evolving from the Last Universal Common Ancestor (LUCA).

    • Later appearance of insects, reptiles, mammals, and humans.

Pathogens Overview

  • Infectious vs Non-Infectious:

    • If diseases are caused by microbes, they are termed infectious or communicable.

    • Non-infectious illnesses do not spring from microbial causes.

Communicable versus Noncommunicable Diseases

  • Statistics:

    • 30 percent of global deaths caused by communicable diseases.

    • Significant decreases observed:

    • Measles (decreased by 94 percent).

    • Diarrheal diseases (decreased by 67 percent).

    • Non-communicable diseases like diabetes decreased by 53 percent.

Numerical Data Comparison: USA vs World

  • Graphs Review:

    • USA Data:

    • Communicable diseases (50 deaths per 100,000) vs Non-communicable diseases (450 deaths per 100,000).

    • Global Data:

    • Communicable diseases (200 deaths per 100,000) vs Non-communicable diseases (600 deaths per 100,000).

Further Exploration of Deductive and Inductive Reasoning

  • Detailed Examples:

    • Deductive: Caution employed based on general knowledge of virus introduction through unknown emails.

    • Inductive: Repeated instances leading to a conclusion regarding risks of unknown attachments.

Phylogeny Illustration

  • Diagram Explanation:

    • Three primary cell lines displayed: bacteria, archaea, and eukarya.

    • Sub-level branches representing distinct microbial groups within these categories are accurately depicted.