Lecture 19. Microbial Diversity

1
Lecture 19. Microbial Diversity
reading Chapter 4
2
Bacterial Domain
3
Deep Branches

• Aquificales - Aquifex water maker
• - H2 1/2 O2 ? H2O
• - autotrophs (CO2 as a carbon source)
• chemolithotrophs (gain energy by oxidation/
• reduction of inorganic chemicals)

Octopus Spring
4
Deep Branches, cont.
Thermotogales - Thermotoga sheath-like envelope
(toga) anaerobic fermenter of sugars up to
90C Thermodesulfobacterium sulfate
reducing bacterium H2 SO42- ? H2S thermophilic
anaerobe grow up to 94C
5
Deep Branches, cont.
Thermus aerobic organotroph thermophilic Taq
polymerase - used in PCR (the polymerase chain
reaction) Deinococcus mesophile related to
Thermus extremely resistant to ionizing
radiation desiccation uv found in soil,
ground meat dust, air, deserts cores of nuclear
reactors
Mushroom Spring, Yellowstone
6
Proteobacteria
major lineage of bacteria extreme metabolic
diversity 5 major groups ? ? ? ? ? Purple
Non-Sulfur Bacteria anoxygenic photosynthesis
(doesnt generate O2) lakes, mud, soils,
sewage energy source light C source CO2 or
organic compounds reductant organic
compounds Purple Sulfur Bacteria anoxygenic
photoautotrophs sulfur springs, anoxic zones in
lakes energy source light reductant H2S H2S ?
S ? SO42-
Rhodospirillum
7
Proteobacteria, cont.
Nitrosomonas
Nitrifying bacteria oxidize nitrogen compounds C
source CO2 oxidant O2 reductants NH3, NH2OH
(hyroxylamine), NO2- soil, sewage, freshwater and
marine species S and Fe oxidizers H2S O2 ?
H2SO4 S O2 ? H2SO4 (thiosulfate) S2O32- O2
? H2SO4 neutrophiles and acidophiles
Nitrosococcus
Beggiatoa
Thioploca
Thiobacillus
8
Proteobacteria, cont.
Hydrogen oxidizers H2 1/2 O2 ? H2O some can
grow on CO found in soil and water Methanotrophs
oxidize methane aerobically mud, marshes, rumen,
mammalian intestines, sediments CH4 O2 ?
CO2 Enterics E. coli, Salmonella,
Shigella organotrophs Rickettsias obligate
intracellular pathogens closely related to
mitochondria
Ralstonia
Methylomonas
Rickettsia
9
Proteobacteria, cont.
Caulobacter
Budding/Stalked Bacteria Caulobacter aquatic
organisms - attach to rocks have specialized
cells mother cells and swimmer cells Myxobacteria
make fruiting bodies - myxospores gliding
bacteria found on decaying wood, dung pellets,
soil, bark complex developmental lifecycles -
intercellular communication Sulfate
Reducers aquatic environments and
sediments diverse group
Myxococcus
Chondromyces
Desulfovibrio
10
Low GC Gram Positives
Lactococcus
Pathogens, commensals Streptococcus,
Staphylococcus Lactococcus/Lactobacillus aerotole
rant fermenters make cheese and other dairy
products Spore-formers found mostly in
soils aerobic and anaerobic organotrophs Bacillus
and Clostridium Sulfate reducers diverse
group soils, oil wells, sediments
Lactobacillus
Bacillus
Clostridium
11
Low GC Gram Positives
Heliobacterium
Heliobacteria anoxygenic photosynthesis also
spore formers found in soils
High GC Gram Positives
not related to low GC gram positives many are
pathogens Mycoplasma, Ureaplasma,
Corynebacterium, Mycobacterium Propionibacterium
holes in Swiss cheese fermenters (produces
CO2) also causes acne
12
High GC Gram Positives, cont.
Actinomycetes live in soils aerobic degraders of
organic compounds filamentous branching
filaments most form spores make earthy odor of
soils from geosmins make antibiotics
(tetracycline, erythromycin)
Streptomyces
13
Cyanobacteria
oxygenic photosynthesis (generate O2) CO2 H2O ?
O2 CH2O unicellular, filamentous, and
colonial very diverse good fossil record aquatic,
soils, hot springs, endoliths (live inside
rocks), deserts, Antarctica, microbial
mats grow up to 72C (upper temperature limit
for photosynthesis) large number fix nitrogen (N2
---gt NH3 ---gt proteins, RNA, DNA)
14
Green Sulfur Bacteria
Chlorobium
anoxygenic photosynthesis C source CO2 reductant
H2S H2S ? S ? SO42- aquatic environments where
H2S is abundant, hot springs
Green Non-Sulfur Bacteria
anoxygenic photosynthesis C source CO2 or
organic compounds reductant organic
compounds live in hot springs, microbial
mats many are thermophilic
Chloroflexus
15
Spirochaetes
tightly coiled morphology unusual form of
motility many are pathogens (lyme disease,
leptospirosis, syphilis) wide spread in aquatic
environments, termite guts and black
mud microaerophiles and aerobes organotrophs
Treponema
Borrelia
16
The Archaeal Domain
17
Methanogens and the C Cycle
Estimated global production of methane 109
tons/yr. A cow can produce 100 liters of methane
a day. Methane is an important greenhouse
gas. Methanogens are found in many places in the
Euryarchaeota.
18
Methanogens
Thermophilic species H2 and CO2 to make
CH4. Methanopyrus -isolated from sediments near
submarine hydrothermal vent chimney -generation
time is 1hr at 100C -branches at the base of the
archaeal tree Mesophilic species can also make
methane from simple organic compounds
(formate, acetate, methanol, methylamines)
Methanocaldococcus jannaschii - 85C
Methanopyrus kandleri - 100C
19
Euryarchaeota
Thermoplasma thermoacidophile aerobic or
anaerobic sulfur respiration found in acidic
soils and coal refuse piles
Picrophilus related to Thermoplasma grows
optimally at pH 0.6 (can grow at pH
-0.06!) membranes leak at pH 4 solfataras
20
Early branching hydrothermal Vent Euryarchaeota.
Thermococcus (hot ball, growing at
70-95C) spherical, highly motile anaerobic
chemoorganotroph Pyrococcus (fire ball,
growing at 70-106C) close relative of
Thermococcus
Thermococcus celer
Pyrococcus furiosus
21
Archaeoglobus
Hyperthermophilic sulfate reducer. Hot marine
sediments and hydrothermal vents. Shared many
unique traits with methanogens weird
enzymes Cultures produce small amounts of
methane. Closely related to methanogens. Sulfate
reduction genes from the bacterial domain via
lateral gene transfer.
.
22
Halobacterium, Haloferax, Natronobacterium
Late branches in Euryarchaeota. Aerobic
organotrophs. Halo- in neutral pH
environments. Nat- in alkaline environments.
Halobacterium
Halogeometricum
Haloarcula
Natronococcus
23
Crenarchaeota
Sulfolobus S-rich acidec hot springs thermoacidop
hile aerobic chemotroph oxidizes H2S or S to
H2SO4
Sulfur Caldron
24
Crenarchaeota, cont.
Thermoproteus long thin rods strict anaerobes S
reducer (likely an ancient metabolism)

25
Submarine Vent Crenarchaeota
Pyrodictium (fire net) Topt 105C network of
fibers attach to other cells strict
anaerobe chemolithotroph or chemoorganotroph Pyro
lobus (fire lobe) Topt 106C holds the upper
temperature record (species can grow gt
113C) walls of black smoker chimney chemoautotrop
h
26
Lecture 20. Proterozoic Earth, Rise in Oxygen,
Microbial Paleontology
reading Chapter 4