Download The 5 Kingdom System: R.H. Whittaker Two kinds of cells: simple

Kingdon Monera: Bacteria and Cyanobacteria
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The 5 Kingdoms and the Prokaryote vs. Eukaryote split
Microbial Systematics
Morphology and other defining characteristics
υ Size, shape and arrangement
υ External Surface Structures
Φ Glycocalyx
Φ Cell Wall: G+/GG+/GΦ Plasma membrane
υ Bacterial Motility
Φ Flagellar,
Flagellar, gliding and spiral movement
Internal structures and endospores
Reproduction: Binary fission
Clinical and Biological Tools for Classification
Two kinds of cells:
simple and complex
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Prokaryotic:
Prokaryotic: small, simple
cells, with no internal
membrane bound organelles.
Includes the bacteria.
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Eukaryotic:
Eukaryotic: larger, more
complex cells with membrane
bound organelles (like nuclei,
mitochondria). Includes
protists, fungi, plants and
animals.
The 5 Kingdom System: R.H. Whittaker
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Autotrophs: organisms that are capable of synthesizing their own high energy
carbon molecules from simple inorganic molecules
Heterotrophs: Organisms that obtain their high energy carbon compounds
compounds in a
premade form and use them directly for energy and structural components
components
Microbial Systematics
Cladogram: A diagramatic tree based on shared and
derived characteristics. Does not describe chronology.
K. Monera - Prokaryotes
Eubacterial Structure & Diversity:
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The 1st Evolutionary Wave
υ Affected change
υ Defined metabolism
4000 described species
υ Estimated .4.4-4 million sp.
Minimal structural diversity
Tremendous metabolic
diversity: autotrophic and
heterotrophic
Incredible abundance
Ecological roles as
decomposers, nutrient cycling
and availability
Pathogenesis
Cell Size: Prokaryotes vs eukaryotic cell
1-10µm vs 10-100µm
Bacterial Size, Shape and Arrangement
Coccus
Bacillus
Spiral
General Features of Bacterial Morphology
Colony Characteristics of Bacteria in
Culture on Solid Growth Media
The Glycocalyx:
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Enhances virulence (Frederick Griffith,
1928 ): attachment and resistance
Composed of carbohydrates and
proteins
Varies in thickness
Forms the foundation of “biofilms”
biofilms”
Cell Wall: Protection from osmotic shock
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Structural determinant of shape
Gram staining: A clinical tool for
distinguishing cell wall composition
(Gram(Gram-positive and gramgram-negative
bacteria)
External features of bacterial morphology
involved in attachment and locomotion:
Fimbriae and pili: bacterial
surface appendages for adhesion
R&T: Directed movement that
relies on receptor mediated
chemotaxis
Endospore Formation: A survival strategy where
sporulation yields a highly resistant particle.
Bacterial Motility: Flagellar and
other forms of motility
Cytoplasmic Features of Bacterial Morphology
Bacterial Reproduction
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Spore formers include: Bacillus
sp. and Clostridium sp.
Water and a few key molecules
can trigger germination.
Its all about survival, not
reproduction.
Binary Fission:
υ Asexual
υ No vegetative state
υ Simple division w/ a
short generation time
υ Effects of the
environment on GT
Metabolic Diversity: Screening
for nutrient metabolism
Bacterial classification/identification:
A hierarchy of methods
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1. Size, shape and arrangement: microscopic
evaluation
2. Colony morphology: macroscopic evaluation of
colonies in culture
3. Chemical analysis: Staining for cell wall
structure and inclusions
4. Physiological and biochemical characteristics:
nutrient and Abx screening
Bacterial classification/identification:
A hierarchy of methods cont’d
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5. Serology: utilizing the specificity of
antibody binding
6. Genetic and molecular analysis: CG
content, hybridization, RFLP, DNA and
rRNA sequencing
Metabolic Relationship to Oxygen:
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Obligate Aerobes:
Aerobes: require
O2 for respiration
Facultative Anaerobes:
Anaerobes: can
respire aerobically or can
carry out fermentation
Obligate Anaerobes:
Anaerobes: are
poisoned by the presence of
O2
Metabolic Diversity Among Prokaryotes
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2 Universal Requirements:
υ Energy source for ATP synthesis: phototrophs (“
(“lightlightfeeders”
feeders”)or chemotrophs (“
(“chemicalchemical-feeders”
feeders”)
υ Carbon source for making building blocks: autotrophs
or heterotrophs
4 Microbial Strategies
υ Photoautotrophs: carry out photosynthesis and can be
either oxygenic or anoxygenic
υ Chemoautotrophs*: oxidize inorganic compounds
υ Photoheterotrophs*: use light but still must eat organic
carbon
υ Chemoheterotrophs: eating organic carbon supplies all
of their needs
Φ Saprobes
Φ Symbionts including parasitic species
Metabolic Relationship to
Temperature: In nature
and in culture…
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Psychrophiles: 00-20˚
20˚C
Mesophiles: 2020-40˚
40˚C
Φ Most pathogens
Φ Psychrotolerant
bacteria
Thermophiles: 404090˚
90˚C
Evolution of Metabolic Diversity: A
cause and effect of changing environments on earth.
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Generation 1:
1: Sampling the soup…
υ Chemoautotrophs
Generation 2:
2: Tapping into solar power…
υ Photoheterotrophs
Generation 3:
3: The origin of photosynthesis…
υ Anoxygenic photoautotrophs (H2S)
Generation 4:
4: Oxygenic photosynthesis
υ Oxygenic photoautotrophs: Cyanobacteria (H2O)
Generation 5:
5: Stepping up to aerobic metabolism...
υ Anaerobic heterotrophs
υ Aerobic heterotrophs
Ecological Importance and Impact of
Prokaryotes
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Nutrient Cycling:
υ Decomposers
υ Carbon fixation
υ Nitrogen fixation
υ Others
4 patterns of symbiosis:
υ Mutualism: +/+
υ Commensalism: +/0
υ Parasitism: +/+/-
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Φ
Φ
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Foreign pathogens
Opportunistic pathogens
Synergism: ++/?
The Domain Eubacteria
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Microbial Systematics
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The Archaebacteria
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Distinguishing features
from the Eubacteria
υ Cell wall differences
υ Cell membrane
differences
υ rRNA sequence
differences
υ DNA sequence analysis
Extremophiles
υ Thermoacidophiles
υ Methanogens
υ Extreme halophiles
Very diverse, most have
peptidoglycan in their cell wall
Beneficial to ecosystem, only a
minority are pathogenic
Gram +: most are
chemoheterotrophs
Gram -:
υ Cyanobacteria photoautotrophs
υ Proteobacteria photoheterotrophs,
chemoautotrophs,
chemoheterotrophs
υ Spirochetes and Chalmydias
The Germ Theory of Disease
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1875 - Robert Koch:
Studied the carcasses of
dead sheep and cattle to
determine cause of death.
υ Isolated microbes and
made the first definitive
connection between
microbes and disease.
υ Established Koch’
Koch’s
Postulates
All organisms can be divided into either of two major
groups based upon their pattern of cell structure:
Characteristic Prokaryotic Cell
Eukaryotic Cell
size
ave. size 1-10 µm
ave. size 10-100 µm
nucleus
nucleoid
(no membrane)
single circ. loop of
naked DNA
absent
membrane bound
chromosomes
organelles
ribosomes
flagella
cell wall
cell reproduction
present as smaller 70S
form
Solid core made of
flagellin
present in most sp. as
peptidoglycan
binary fission
linear, arranged with
histones in pairs
present, vary with
cell function
present as larger 80S
form
9+2 arrangement of
microtubules
absent or different in
composition
mitosis and sexual
reproduction