BIOL 260-General Microbiology Instructor: Christopher Thor Masters Degree, Bioengineering Bachelors Degree, Molecular Biology

Welcome to BIOL 260: Microbiology! First day: Review of Syllabus Sign-in Introduce the course, review course expectations Begin with first lab Exercise 3: Microscope Lab

What is microbiology? The scientific discipline which studies microbes or microorganisms Biology of microbes The interaction of microbes with other microbes, the environment, and humans

The “Yotes” Definitions: Prokaryote: Single celled organism, no nucleus. Bacteria, Archaea Eukaryote: Single or multi-celled organism, membrane bound nucleus Algae, Protozoa, Fungi, people

What are examples of microbes? Algae Fungi Protozoa Bacteria Viruses Eukaryotes: Protozoans, Fungi, Algae, Prokaryotes: bacteria Which are Prokaryotes are which are Eukaryotes?

Hierarchy

Types of Microbes: Algae

Types of Microbes: Protozoa

Types of Microbes: Fungi

Types of Microbes: Bacteria

Viruses, Viroids, Prions

Microorganisms are associated with Disease Cause of many epidemics in history Bubonic plague (1346-1350) Killed 25 million people Small pox Killed estimated 600 million people since 10,000 BC Eradicated in 1979 HIV 3.1 million estimated new cases per year 5% of Sub-Saharan Population Malaria Small Pox

Bacteria are associated with Normal microbiota (normal flora) The bacteria that are present on our bodies

Bacteria are associated with The environment Rhizobium (the greatest bacteria you’ve never heard of) Nitrogen fixation in the soil Food products Beer! Or bread, wine, sauerkraut, yogurt, cheese… Medicines Bacteria are “programmed” to make insulin

History of Microbiology It all started with the microscope! Zacharis Janssen (1600) Antoni van Leewenhoek (1632-1723) Robert Hooke (1665)

Zacharis Janssen’s microscope Modeled after the telescope Consisted of two lenses Magnified images 3-10X

Leewenhoek’s microscope 20-30x magnification

Where do cells come from? Spontaneous generation Francesco Redi (1668) Spontaneous Generation does not occur John Needham (1745) Spontaneous Generation does occur Lazzaro Spallanzani (1765) Louis Pasteur (1861) Biogenesis Rudolf Virchow (1858) Living things come from living things

Pasteur’s flasks

John Tyndall questions Pasteur’s experiments Could not reproduce Pasteur’s results Specific growth media required Found that there were heat resistant forms of microbes Same year (1876) Ferdinand Cohn discovers heat resistant forms of bacteria called endospores Spores can survive in space (Apollo Program, 1960s) 1877 Robert Koch demonstrates that anthrax caused by Bacillus anthracis

Major Milestones in Microbiology

Major Milestones in Microbiology

New cells need to be placed in categories Aristotle-plant or animal kingdom Kingdom Protista (1866) Electron microscope (1940’s) Kingdom Procaryotae (1968) Carl Woese proposed 3 Domains (1978)

Three Domain System

Prokaryotes (Single Celled) Bacteria Domain (Eubacteria) Peptidoglycan cell walls Gram negative Gram positive Archaea Domain (Archaebacteria) Not a peptidoglycan cell wall Extremophiles Methanogens Halophiles Thermophiles

Binomial system of nomenclature Genus and species Escherichia coli, E. coli Both names are in italics or underlined and correctly spelled.

Relationship of size and resolution

Types of microscopes Brightfield Darkfield Phase Contrast Fluorescent Electron

Microscopy-Brightfield

Oil has same refractive index as glass

Microscopy Stained specimen Wet mount

Microscopy Stained specimen Wet mount

Microscopy Electron microscopes - maximum magnification 100,000X First TEM - 1931 First scanning - 1941 (commercial 1965) $150/sample

Microscopy Electron microscopes - maximum magnification 100,000X “Color-enhanced” First TEM - 1931 First scanning - 1941 (commercial 1965) $150/sample

Staining: key to visualization Simple Differential Special

Microscopic Techniques: Dyes and Staining Simple stains Stains everything Differential stains Stain based on cellular traits Gram stain - separates bacteria into two categories based on type of cell wall Acid Fast Stain – Stains non-peptidoglycan containing bacteria (Mycobacteria) Gram-positive Gram-negative

Microscopic Techniques: Dyes and Staining Simple stains Differential stains Gram stain - separates bacteria into two categories based on type of cell wall Purple: Bacteria with high peptidoglycan containing cell walls Pink: Counter stain

Differential Stain: Acid Fast

Microscopic Techniques: Dyes and Staining Fluorescent dyes and tags

Special stain: Capsule Stain

Special stain: Endospore Stain

Special stain: Flagella Stain

Morphology of Prokaryotic Cells: Cell Shapes

Morphology of Prokaryotic Cells: Cell Shapes

Morphology of Prokaryotic Cells: Cell Groupings

Morphology of Prokaryotic Cells: Multicellular Associations Biofilm containing mixed species