Download What are microbes

Lecture 1B- Classification
Dr. Souki
General Microbiology
East Los Angeles College
What are microbes (microorganisms)?
• Cells and infectious agents too
small to be seen with the
naked eye
Escherichia coli
Methanogens
– < 0.2 mm (= 200 mm)
• Examples include:
– Bacteria (Escherichia coli,
Salmonella)
– Archaea
Thermophiles
Halophiles
• Extremophiles
– Methanogens
– Halophiles (salt lovers)
– Thermophiles (heat lovers)
– Protozoa
– Fungi
– Viruses (Human
Immunodeficiency Virus
[HIV])
– Viroids
– Prions
• Microbiology
Protozoa
Yeast
Where are microbes?
• Ubiquitous
• Normal flora
– Staphylococcus
epidermidis
• skin
– Escherichia coli
• Colon
– Bacteriodes sp.
• Small intestine
• Pathogenic bacteria
– Helicobacter pylori
– Methicillin-resistant
Staphylococcus aureus
(MRSA)
• Nosocomial
What other diseases are caused by
microorganisms?
Influenza
•
• Septicemia
• Respiratory infections
• HIV/AIDS
– Virus
• Diarrhea
– Bacterial
• Salmonella sp.
• E. coli
• Shigella sp.
– Viral
• Rotavirus
• Norovirus
• Tuberculosis
– Mycobacerium tuberculi
How is microbiology applied?
• Food Production
– GMOs
• Commercial Products
– Antibiotics &
vaccines
• Bioremediation
– Microbes used to
degrade organic
wastes
• Genetic Engineering
– Microbes
engineered to
produce new
compounds
– Recombinant
DNA technology
• Ex: Insulin,
Vaccines
How is microbiology applied?
Bacteria Lactobacillus
species
and others
Various bacteria
(Lactococci sp.,
Lactobacillus sp.,
Streptococcus sp.
and/or yeast
yeast Saccharomyces
1. What is a microbe?
2. List 7 types of microbes.
3. Contrast bacteria and prions. How are they
different?
4. List 3 practical uses for microbes. Explain
how each is useful to society.
How are living things classified?
• Common characteristics
–
–
–
–
–
Physical characteristics
Life cycles
Nutrient requirements
Biochemical processes
DNA similarities
• Mitochondrial DNA
• Chloroplast DNA
• Nuclear DNA
• Taxonomy - study of
classification of species
– Cladistics
• Links organisms to common
ancestor
Classifying Living Organisms:
The Three Domain System
Developed by Carl Woese
Based on 16S rRNA nucleotide sequence
How are organisms named?
• Binomial nomenclature
• Developed by Carolus
Linnaeus ~ 1735
• Each organism is given a
genus and species name
• Example: Staphylococcus
aureus
– Genus names are like last
names
– Species names are like
first names
• Where do names come
from?
– description of an
organism / habitat / in
honor of a researcher /
misc.
• Always italicize or
underline genus & species
Naming Microbes
• Example: Staphylococcus aureus
• Genus:
• Species:
1. What is a species?
2. Explain how cladistics helps scientists with
taxonomic classification of various species.
3. Who is Carl Woese?
4. Who is Carolus Linnaeus?
5. What are the three domains? List major
members of each domain.
What are prokaryotes & eukaryotes?
Domain - Bacteria
•
•
•
•
Single-celled organisms
Prokaryotic – lack nucleus
Simple shapes – round, rod, spiral
Cell walls - peptidoglycan
Domain - Archaea
•
•
•
Single-celled organisms
Prokaryotic – lack nucleus
Cell wall WITHOUT
peptidoglycan
•
3 main groups:
1. Methanogens
2. Extreme halophiles
3. Extreme thermophiles
What are eukaryotic microorganisms?
• Includes the kingdoms
–Fungi
–Protista
–Animalia
–Plantae
Domain – Eukarya
Kingdom Fungi
•
Includes:
1. Yeasts – unicellular
2. Molds – multicellular
3. Mushrooms – multicellular
•
Absorb nutrients from environment
• Unicellular
organisms
• Eukaryotic – have
nucleus
• Motility by:
-- Cilia
-- Flagella
-- Pseudopodia
• Are free-living or
parasitic
• Protozoa cause
diseases:
– Malaria
– Giardiasis
– Amoebic
dysentery
Domain – Eukarya
Kingdom Protista
• Flatworms
Domain – Eukarya
Kingdom Animalia
Phylum Platyhelminthes
– Liver flukes
• Cause fascioliasis
– Fluke found in bile
duct & liver
• Transmission:
– Contaminated
water
– Eating vegetables
washed/irrigated in
contaminated
water
• Raw watercress
– Eating undercooked
liver/snails
• Roundworms
Domain – Eukarya
Kingdom Animalia
Phylum Nematoda
– For example:
Ascaris
• Causes infections
of GI tract
• Transmission:
– Eggs leaves body
in feces
– Ingestion food
contaminated
with dirt
containing eggs
• Diagnosis:
– Eggs in stool
– Cough up worm
Graphic
Content
• Segmented
worms
Domain – Eukarya
Kingdom Animalia
Phylum Annelida
– Leech
• Blood suckers
• Hirudo
medicinalis
– Used in early
(1800s) bloodletting
treatments
• Hirudin
anticoagulant
– Currently used in
limited
procedures
Graphic Content
Non-living Infectious Agents Viruses
• Require host cell
for reproduction
• Obligate
intracellular
parasites
Ebola
• Simple structures:
– Nucleic acid
• DNA or RNA
•
Capsid
– Protein coat
• Envelope
• NO
ORGANELLES
Influenza
Influenza
Non-living Infectious Agents Viroid
• Require host cell for
reproduction
• Obligate intracellular
parasites
• Simple structures:
-- RNA only
• Plant parasites
• Hep D in humans
Non-living Infectious Agents Prions
• Protein in misfolded
form
• For example:
– Bovine spongiform
encephalitis (BSE)
– Creutzfeldt-jakob
disease
• Misfolded protein
causes other
proteins to become
misfolded
• Results in
neurodegeneration
1.
2.
3.
4.
5.
What is an organelle?
Define prokaryote and eukaryote.
Which 2 domains are prokaryotic?
List various eukaryotes.
Are virus, viroids, and prions considered
living? Explain why or why not.
6. What are the three main groups of
archaea?
7. List 3 helminth phyla. Which are
pathogenic?
8. What are protozoa?