The Microbial World and You (an introduction)
Section 1: What is Microbiology?
Microbiology: study of microorganisms
Types: bacteria, fungi (yeast), algae, protozoa (tiny animals), virus,
archaea (cousins of bacteria, extreme loving)
- Similarities: single cells, they are very small,
What do you think of when you hear of bacteria?
- Typically has a negative connotation
- Tend to only think of their:
- Disease, germs, food spoilage
2016-threat to human reproductive health
- Zika virus: a virus transmitted by mosquitoes
- Infection during pregnancy is a cause of microcephaly and other
abnormalities in the developing child
- The brain neurons is eaten away by the virus
- There is no treatment
2014- Ebola outbreak
- Deadly virus
We fail to appreciate how important the microorganisms are
Role in environment:
- O2 production: (80% of the O2 in the atmosphere comes from algae)
- Soil enrichment: ( bacteria in soil take up nitrogen in the atmosphere
and make it available to plants as fertilizer)
- Decomposition :(decomposers and naturally remove wastes)
- Bioremediation (oil spill clean up, feed on the oil)
Role in human health:
- Normal flora/microbiota: play a role in our own digestive tract
(nutrients/immune stimulation)
- Food production: wine and cheese are made when microbes (yeast and
bacteria) ferment sugars, yogurt, bread (yeast produces Co2 gasses to
make it rise)
, - Disease treatment: recombinant protein production/purification of
insulin for treatment of diabetes
- Novel therapeutics
Role in research and development:
- Tolls in research: cloning, recombinant DNA tech
- Produce chemical products and consumables: ethanol, acetone,
vitamins. Plastic production from genetically engineered microbes
- And even fashion: used to bleach denim for distressed look
Importance of microorganisms:
- Not all microbes are pathogenic (of all the trillions of organisms on 1-2%
are bad)
- Without them, life would not be the same
- As scientists we are constantly working to increase our understanding
of them
- Understand causes/transmission of infectious diseases to be
better able to prevent disease epidemics
- Prevent food spoilage
- Harness the properties of microorganisms to better our
environment, health, and daily lives
Section 2: Naming and Characterizing Microorganisms
Binomial naming system:
a. Kingdom, phylum, order, family, genus, species
Each organism has a unique binomial name:
- Carolus linnaeus established the system of scientific nomenclature in
1735
- Each organism has two names: the genus and the specific epithet
(species) - very important when discussing microorganisms
- Are used worldwide
- Usually descriptive, but some names are given to honor a scientist
- Specific binomial names:
- Typically in latin
- Always italicized when typed
- Many times the genus name is abbreviated to the first initial
, - Used universally to help avoid confusion
Descriptive example:
- Staphylococcus aureus:
- Genus: describes the clustered (staphylo-) spherical (coccus)
cells
- Species: describes the gold-covered (aureus) colonies
- Commonly abbreviated S. aureus
- Streptococcus pneumoniae:
- Genus: describes the twisted strand (strepto) spherical (coccus)
cells
- Species: describes the bacterium’s habitat (lung)
- Commonly abbreviated: S. pneumoniae
- Escherichia coli:
- Genus: honors the discovered, Theodor Escherich
- Species: describes the bacterium’s habitat- the large intestine,
or colon
- Commonly abbreviated: E. coli
Section 3: Diversifying and Unifying Characteristics of Microorganisms
Unifying characteristics:
- Microscopic
- Live as an independent units:
- 1 cell = 1 E. coli cell
- 1 viron = 1 HIV particle
- Very fast reproduction/generation times (20 minutes)
- Compared to non-microorganisms
- Mainly prokaryotic/less complex
Diversifying characteristics:
- No one single structure
- Diverse habitats (found from Antarctica to hydrothermal vents in the
ocean, and everywhere in between)
- Reproduction methods vary (asexual vs. sexual)
Taxonomy:
- Three domains:
- Bacteria ( includes all bacteria)