Chapter 1 Chapter 1

The Microbial World and YouThe Microbial World and You

What are microorganisms?What are microorganisms?

Too small to be seen with the unaided eyeToo small to be seen with the unaided eye

True cellular forms True cellular forms

UbiquitousUbiquitous

Both helpful and problematicBoth helpful and problematic

Scope and Relevance of MicrobiologyScope and Relevance of Microbiology

First living organisms on the planetFirst living organisms on the planet

Live everywhere life is possibleLive everywhere life is possible

Largest component of Earth's biomass Largest component of Earth's biomass

Ecosystems depends on their activities Ecosystems depends on their activities

Why study microbes?Why study microbes?

Recycling vital elementsRecycling vital elementsBioremediation Bioremediation AgricultureAgricultureBiotechnology/ Genetic engineering Biotechnology/ Genetic engineering Food microbiologyFood microbiologyIndustrial MicrobiologyIndustrial MicrobiologyNormal microbiota Normal microbiota Disease causing microorganismsDisease causing microorganisms

Common AncestorCommon Ancestor

Gave rise to 3 DomainsGave rise to 3 Domains Two prokaryoticTwo prokaryotic

Bacteria and ArchaeaBacteria and Archaea One eukaryotic One eukaryotic

Eukarya Eukarya

ProkaryotesProkaryotesAsexual; unicellular, no membrane bound organellesAsexual; unicellular, no membrane bound organelles

ArchaeaArchaea Not known to be human pathogens Not known to be human pathogens Usually found in extreme environments Usually found in extreme environments

BacteriaBacteria Some pathogenic Some pathogenic Multiple morphological and physiological differences Multiple morphological and physiological differences

from archaeafrom archaea

Rod Shaped Bacteria Rod Shaped Bacteria

Many Klebisella pneumoniae cells

Round ArchaeaRound Archaea

Methanococcus janaschii, with numerous

flagella attached to one side

EukaryotesEukaryotesUnicellular or multicellularUnicellular or multicellular

Sexual and asexual reproductionSexual and asexual reproduction

Multiple membranous organelles Multiple membranous organelles

AlgaeAlgaeUnicellular or multicellularUnicellular or multicellular

PhotosyntheticPhotosynthetic

High morphological diversityHigh morphological diversity

Not pathogenicNot pathogenic

Cymatopleura

Volvox

Macrocystis pyrifera

Gelidium pulchrum Alexandrium tamarense

Amanita muscaria

Aspergillus flavus

Rhizopus Saccharomyces cerevisiae

•FungiFungi•Unicellular or multicellularUnicellular or multicellular•Absorb nutrients from their environmentAbsorb nutrients from their environment•Primarily opportunistic pathogensPrimarily opportunistic pathogens

ProtozoaProtozoaUnicellular Unicellular

Most are mobile Most are mobile Pseudopods, Flagella, CiliaPseudopods, Flagella, Cilia

Absorb nutrients from environment or live as Absorb nutrients from environment or live as parasites parasites

Manyare pathogenicManyare pathogenic

Giardia lamblia

Amoeba

Paramecium

HelminthsHelminthsMulti-cellular animalsMulti-cellular animals

Flatworms and round wormsFlatworms and round worms

Many are pathogenicMany are pathogenic

Only some life stages Only some life stages microscopicmicroscopic

Taenia taeniformis

Necator americanus

VirusesViruses Obligatory intracellular Obligatory intracellular

parasiteparasite No true cellular organizationNo true cellular organization Living or non-living???Living or non-living??? HIV virus on the surface of a

CD4+ cell

Bacteriophages

Size in the Microbial WorldSize in the Microbial World

History of MicrobiologyHistory of Microbiology

Robert Hooke -1665Robert Hooke -1665

Anton van Leeuwenhoek - Anton van Leeuwenhoek - 16731673 "animalcules" "animalcules"

Schleiden and Schwann- Schleiden and Schwann- 1838/391838/39 Cell theory Cell theory

Spontaneous GenerationSpontaneous Generation

Franscesco Redi – 1668 Franscesco Redi – 1668

John Needham – 1745John Needham – 1745

Lazzaro Spallanzani - 1765Lazzaro Spallanzani - 1765

Rudolf Virchow -1855Rudolf Virchow -1855

Louis Pasteur – 1861Louis Pasteur – 1861 Aseptic techniques Aseptic techniques

Golden Age of Golden Age of Microbiology Microbiology (1874 – 1914)(1874 – 1914)

Support theories that invisible agents cause Support theories that invisible agents cause diseasedisease Ignaz Semmelweis - 1840Ignaz Semmelweis - 1840

Childbed feverChildbed fever Joseph Lister - 1867Joseph Lister - 1867

Aseptic surgeryAseptic surgery John Tyndall John Tyndall

Microbes in dust, some heat resistant Microbes in dust, some heat resistant

Germ Theory of DiseaseGerm Theory of Disease Pasteur Pasteur

Fermentation (1857) and pasteurization (1864)Fermentation (1857) and pasteurization (1864)

Robert Koch - 1876Robert Koch - 1876

Walther Hesse – 1882Walther Hesse – 1882

VaccinationVaccination Edward Jenner – 1798Edward Jenner – 1798

Smallpox vaccineSmallpox vaccine Louis Pasteur – 1880Louis Pasteur – 1880

Avirulence Avirulence

Rabies vaccineRabies vaccine

ChemotherapyChemotherapy

1908, Paul Ehrlich1908, Paul Ehrlich

Salvarsan – treatment for syphilisSalvarsan – treatment for syphilis

1928, Alexander Fleming1928, Alexander FlemingDiscovered properties of penicillinDiscovered properties of penicillin

1935-36, Gerhard Domagk & Ernest Fourneau1935-36, Gerhard Domagk & Ernest FourneauDevelopment of sulfa drugsDevelopment of sulfa drugs

1940, Selman Waksman1940, Selman WaksmanIsolated antibiotic from Isolated antibiotic from StreptomycesStreptomyces

1940, Howard Florey & Ernest Chain1940, Howard Florey & Ernest ChainPreformed clinical trials and mass produced Preformed clinical trials and mass produced penicillinpenicillin

Problems with modern chemotherapeuticsProblems with modern chemotherapeutics ToxicityToxicity ResistanceResistance Lack of adequate anti- viral drugs Lack of adequate anti- viral drugs

Infectious disease remains a threatInfectious disease remains a threat 750 million cases each year in US750 million cases each year in US

Emerging diseasesEmerging diseasesFactors associated with emerging diseaseFactors associated with emerging disease

Microbial evolution Microbial evolution Changing human behavior/lifestylesChanging human behavior/lifestyles Complacency of human population Complacency of human population Population expansion/global travel Population expansion/global travel