Microbiology 205
Introduction to Microbiology
Gary W. Childers
Biology BLD 238 (old Building)
Ph. 985 549 3503
gchilders@selu.edu
What is Microbiology?
What are they?
How we classify Microorganisms
What do they do?
Importance to earth, ecology, and humans
Where do they do it?
Niche / environment / tolerances
How we study Microorganisms
Tools and techniques to study microbiology
Definition of Microbiology
Study of microorganisms and their interactions
Prokaryotes
Bacteria
Archaea
Algae
Protista
Eukaryotes
Protozoa
Fungi
Viruses ?
Tree of Life
Tree of life consists of 3 Domains
2 of the 3 are exclusively microorganisms
1 (Eucarya) is both micro and macroscopic
Tree of Life based on comparison of Ribosomal nucleotide sequences
Figure 1.4 Diagram of Stanley
Miller’s apparatus
500 ml water (Ocean)
Gases (CH4, NH4, H2) ATM
Condenser (rain)
60,000 volt spark (Lightning)
Continuous recycling
Tarry liquid AA, acetate, formate
Comparison of Prokaryotes and Eukaryotes:
Feature:
Size
Organelles
DNA
Ribosomes
(RNA)
Morphology
Cell Wall
Flagella
Prokaryotes
Small (0.5-1.0µM)
NO
Circular/haploid
70S 50S 30S
5S 23S 16S
single cell
Yes
Yes/no-one fibril
Cell Membrane
bilayer/monlayer
ester/ether
FA/glycerol
Eukaryotes
Large (5-20 µM)
Yes
Linear/diploid
80S 60S 40S
5.5S 5S & 28S 18S
single/multicellular
yes/no
yes/no- 9+2
centrioles
bilayer
ester
FA/glycerol
Prokaryote vs Eukaryote
Contrast
Bacteria
Archaea
Morphology
Size
Cell wall
Ribosomes
Polymerase
Reproduction
Feeding
rods/cocci/spirals/filaments
µM 0.5-5
µM 0.5-5
Peptidoglycan
No PTG
70s
70s
Prokaryotes
Eukaryotes
Binary fission
Binary Fission
Saprotrophically Saprotrophically
Classification of Microorganisms
By Nutrition
Chemotrophs Acquire Energy (E) from Chemical Compounds
Chemoheterotrophs
E for organic Compounds (Glucose)
Carbon (C) for synthesis from organic Compounds
Chemoautotrophs (chemolithotrophs
E from inorganic compounds (Hydrogen)
C for synthesis from Carbon Dioxide (CO2)
Phototrophs: Acquire E from sunlight
Photoheterotrophs
E from Sunlight
C for synthesis from organic substrates
Photoautotrophs (Photolithotrophs)
E from sunlight
C for synthesis from CO2
Hallmarks of Bacteria
Small size
Single celled
Asexual reproduction
Unrestricted growth
Metabolic diversity
Common morphologies of microorganisms
Size of microorganisms
100 microns
~ 100 E.coli lined up end to end
100 microns
~ 100 E.coli lined up end to end
Large surface area facilitates transport of nutrients
Microbes are efficient “machines”
What do microorganisms do?
What are their role in the Biosphere
1.
2.
3.
Disease- 5% of described microorganisms
Biogeochemical Reactions-Nutrient cycles C, N, S
Symbionts
Plants Rhizophere/bacteria
Mycorrhizae/fungi
Animals bacteria/archaea
Ruminants (ex: cow) and ruminant microorganisms (ex: Fibrobacter)
also: termites/spirochetes, humans/gut bacteria
4. Food/Agriculture
Nitrogen fixing bacteria (Rhizobium spp., Azotobacter spp., Nostoc spp.)
Dairy/Bread/Alcohol/Solvents (fermenters, yeast, lactic acid bacteria, clostridium)
(Glucose  acetic acid, lactic acid, citric acid, ethanol, carbon dioxide)
5. Sewage treatment 100%
6. Research
Biotechnology (large scale bioreactors, acid mining, biofuels)
Recombinant DNA (cloning, drug discovery)
Bioremediation (oil spill remediation, explosives degradation)
Symbiosis ex: Photobacterium spp.
+VFA’s
Unique Metabolic Diversity
1. Fix atmospheric nitrogen
2. Synthesize Vitamin B 12
3. Use inorganic energy sources:
NH4,H2S, H2, Fe+2, SO4, S°
4. Photosynthesize without chlorophyll/bacterial rhodopsin
5. Utilize inorganic and organic Terminal Electron Acceptors as
an alternate to Oxygen
CO2, NO3, SO4,Mn+4, Fe+3, Fumarate, humic acids
6. Extensive capacity for Anaerobic growth
7. Use H2S, H2 or organic compounds as electron donors for
photosynthesis
8. Growth at high temperatures/salt/pressure
Where Microorganism do it
1. Micro site / Niche: Place of Business / Their profession
Environmental Tolerances
Range of Activity
Cardinal Points
Minimum/Optimum/Maximum
Substrate Limitations
Range of Substrates
Affinity
Growth Rate
Terms used to describe microbial niche, or environment
1. Tolerant/Facultative/Obligate
2. pH : Acidophile/neutrophile/Basophile
3. Oxygen: Aerobic/Anaerobic/facultative
4. Temperature: Psychrophile/Mesophile/Thermophile
5. Osmotic: Halophile/Osmophilic/ Xerophile
6. Substrate: Oleogotrophic/Capiotrophic
How Do We Study Microorganisms?
1. Parameters
Growth Rate (GT, µ)
Enumerations
Measure Substrate Disappearance/Product Formation)
2. Scientific Method
Controls
variables
Optimum Conditions
3. Equipment
Molecular Techniques
Microscopes
Gas Chromatographs
How do we study Microorganism?
Substrate + oxidant-- Product + Cells + Waste
Electron Donor (ED) + Terminal Electron Acceptor (TEA)-
(reduced)
(oxidized)
oxidized product + REDUCED oxidant + CELLS + ATP
Heterotrophic aerobic respiration:
C6H12O6 + 6O2  6CO2 + 6H2O + release of energy
(glucose)
Fire:
CH4 + O2  H2O + CO2 + release of energy