Overview of Microbial Diversity. Three Kingdoms

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Overview of Microbial Diversity. Three Kingdoms
EUKARYOTES
Algae Red - Rhodophyta Brown - Phaeophyta Green -
Chlorophyta Blue-green algae are
BACTERIA Cyanobacteria
Fungi Molds Spores / mycelia / hyphae Yeasts /
budding
Protozoa Motile / unicellular Pseudopodia Phagocyt
osis
PROKARYOTES
BACTERIA - Eubacteria ARCHAEA - Archaebacteria
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How diverse are they?
OXIDISED ATMOSPHERE
Plants Animals

• Diverse range of species
• Earliest life on the planet
• Anaerobic then aerobic
• Three Kingdoms (1977)
• 16S rRNA Analysis
• Eukaryote Plants Animals
• Bacteria
• Archaea
• Extreme living microorganisms

Eubacteria
Archaea
3 3.5 billion years REDUCED ATMOSPHERE
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Microbial Diversity. Three Kingdoms
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Microbial Diversity. The Third Kingdom - Archeae
Summary of Differences
Eubacteria Archaebacteria Peptidoglycan
wall Cell wall variants Ribosomal RNA Very
different RNA polymerase Several
enzymes Membrane lipids Ether-linked/branched P
rotein synthesis Very different No
methanogenesis Some are methanogens Antibiotic
sensitivity Insensitive to many
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General differences between Eukaryotes and
Prokaryotes
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Dimensions of some bacteria
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The largest bacterium known
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Range of cellular morphologies in eubacteria
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General differences between Eukaryotes and
Prokaryotes
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General differences between Eukaryotes and
Prokaryotes cont.
? DIRECTED READING Prescott. Structure Ch3 .
Ch4 Archaea Chapter 23
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Rickettsia and the origin of mitochondria
NATURE 12 November 1998
Complete genome of typhus agent NATURE NEWS
SERVICE
The publication in this week's Nature of the
complete sequence of the genome from Rickettsia
prowazekii, is not only of considerable medical
importance - Rickettsia causes epidemic typhus -
but may also shed further light on the evolution
of mitochondria. Mitochondria are the
energy-generating organelles of most 'higher'
organisms and their origin has been much debated.
It is generally thought that they arose from a
bacterium living symbiotically within a primitive
eukaryote cell. Rickettsia prowazekii appears to
be very much like this hypothesised ancestor.
Alongside the latest research we here re-present
a hypothesis, published earlier this year, which
sought to explain what drove a Rickettsia-like
bacterium to become the ancestral mitochondria. 
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Rickettsia, typhus and the mitochondrial
connection MICHAEL W. GRAYThe genome sequence
of Rickettsia prowazekii, the agent that causes
typhus, has been determined. What emerges is a
snapshot of genome re-tailoring in a parasitic
bacterium, and a new look at the evolutionary
connection between Rickettsia and
mitochondria.
The genome sequence of Rickettsia prowazekii and
the origin of mitochondria SIV G. E. ANDERSSON,
ALIREZA ZOMORODIPOUR, JAN O. ANDERSSON,
THOMAS SICHERITZ-PONTÉN, U. CECILIA M. ALSMARK,
RAF M. PODOWSKI, A. KRISTINA NÄSLUND,
ANN-SOFIE ERIKSSON, HERBERT H. WINKLER  CHARLES G
. KURLAND
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The hydrogen hypothesis for the first eukaryote
WILLIAM MARTIN AND MIKLÓS MÜLLER
A paradigm gets shifty W. FORD DOOLITTLEThe
prevailing view of the origin of complex
eukaryotic cells presumes a symbiosis, based on
respiration, between a bacterium and a primitive
eukaryotic 'host'. But could the symbiosis have
been based instead on hydrogen metabolism, with
the host being an archaean?
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