Environmental Influences on Microbes

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• Environmental Influences on Microbes
• Principles
• Liebigs Law of the Minimum
• biomass determined by the nutrient
• which is LOWEST in relation to requirements
• (Bacterial Bioassay of vitamins)
• Redfield Ratio
• 2) Shelfords Law of Tolerance
• Survival and growth require
• COMPLEX Conditions
• To succeed each must remain within limits.
• (Bacterial Bioassay of (Cu2) (pCu)
• Eury (haline, thermal)
• Steno( )

106C 16N 1P
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Factors Interact to allow survival e.g. Thermal
stress Needs gt nutrients Microenvironments
who sees what? pH Microbial Interactions
Lactic Acid fermentation Alcohol
fermentation Acid Mine Drainage (FeS2 O2
Bugs ? Acid Chemistry availability (Binding,
Speciation) Can we Define the Conditions for
Microbial Life?
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For Organisms Generally Vant Hoffs Law Incgt
10oC 2 X growth Q10 2
Cardinal Temps Minimum Maximum Optimum
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Temperature range -1.8 to 113oC (maybe 121oC
Pyrodictium sp.) Above 100oC must be under
pressure life depends on liquid water Each has
Optimum (lab measured), Range Psychrophiles OT
lt 15oC (deep Ocean, winter arctic) Mesophiles
- OT 25 40/5oC Thermophiles - OT 40 60oC
(compost, hot springs, HT vents) Hyperthermophile
s OT gt 80oC
Pseudoalteromonas Acrtic ocean
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What about Nature? Temperate Environment Chang
e Community Species Adapt (Pohick AA met
same at 5 and 30 oC)
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Temperature Killing Cold Ice Crystals damage
cell membrane/wall leak ? die so freeze slow -
small crystals less damage Cold Osmotic Shock
freeze out water gt salt conc. ? die Heat
Cleave Chemical Bonds C N sensitive H H
very sensitive (gtH bonds gt heat stable) Denature
proteins, NA
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Survival and Function Mesophiles Cold inhibits
by shut down Protein Synthesis gelling of
membranes esp w gtfatty acids inhibits
transport gtgtgt Generation times Accumulate
Toxins NOTE natural communities 4oC can reduce
viability
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Psychrophiles Membranes greater unsaturated
fatty acids even double bonds
(polyunsaturated) SO flexible and active at
lower temps Enzymes also more flexible by gt
alpha helix structure (Fig3.16-17) lt beta sheet
structure (2o structure) Thus more flexible
and gt polar AA and lt hydrophobic AAs less
internal (weak) bonding
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Psychrophiles animals have glycoproteins
act like antifreeze BUT Enzymes Not all
special for some Meso and Psychro have
same Opt. Temp. BUT for others (Vibrio
marinus) max temp 15-20oC then
denature Ordinary bacteria from sea ice
(heterotrophs) lowest max growth temp.
(Pseudoalteromonas)
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Snow Algae Chlamydomonas nivalis green
alga green vegetative but PINK spores
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Thermophiles Prokaryotes (almost)
exclusively Hydrothermal Vents, Hot springs
Archaea at hydrothermal vent (deep sea)
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How do they do that? 1 gt Saturated Fatty Acids
(not melt) Archaea Not FA BUT C40
Hydrocarbons C O C40, Lipid MonoLayer 2 Heat
Stable Enzymes/Protein 1o structure changed
(AAs) gtgt ionic bonds gtgt hydrophobic AA resist
unfolding BUT often only small AA ? B.
stearothermophilus malic dehydrogenase active at
65oC 3 DNA Higher GC ratio gt H bonds 4 Cell
Associated stability (solutes stabilize
Enz) pyruvate oxidase free maxT lt50oC in
cell maxT 65oC
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5 Membranes Lipid Protein heat stable Coat
Protein w lipid heat stable ??Dynamic
Thermophily Grow at gtT fast to repair
damage evidence Q10 lt 2 use gt nutrients for
production die easily if not grow Long
generation times
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Survival Endospores Calcium Dipicolinic
Acid Low Water content Bacillus, Clostridium
(poor nutrient conditions stim.) Halobacillus
(coral) (found in Bahamas)
Clostridium tetani
Bacillus anthracis
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Physical Factors - pH
-log (H) Activity Concentration in Dilute
Solution
Range 0 to 12 (approx) (Define pH
0) Most Bacteria Optimum 6 8 (esp
Pathogens) CW CM remain intact, interior 7,
ATP Synth Acidophilic Optimum ltltlt
7 Thiobacillus ferrooxidans acid mine drainage
(pix) T. thiooxidans Oxidize at pHlt1, survive
pH0 Thermoplasma acidophilum pH 2, 55oC opt
Cell Wall-less Archaea, membrane resist H,
heat lipoglycan, glycoprotein
Mechanism T. thiooxidans membrane not
permeable to H but OK for glucose and amino
acids T. ferrooxidans Fe2 oxidizing enz. Opt.
7, so H not in
.
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Acidity of the water and high metal
concentrations can be deadly to animals and
plants inhabiting the receiving streams. Acid
mine drainage coats stream bottoms with iron
hydroxide, giving the subtrates in impacted
streams an orange color.
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Physical Factors - pH
-log (H) Activity Concentration in Dilute
Solution
Range 0 to 12 (approx) (Define pH
0) Most Bacteria Optimum 6 8 (esp
Pathogens) CW CM remain intact, interior 7,
ATP Synth Acidophilic Optimum ltltlt
7 Thiobacillus ferrooxidans acid mine drainage
(pix) T. thiooxidans Oxidize at pHlt1, survive
pH0 Thermoplasma acidophilum pH 2, 55oC opt
Cell Wall-less Archaea, membrane resist H,
heat lipoglycan, glycoprotein
Mechanism T. thiooxidans membrane not
permeable to H but OK for glucose and amino
acids T. ferrooxidans Fe2 oxidizing enz. Opt.
7, so H not in
.
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Most acidophilic (and thermophilic)
Archaea Picrophilus oshimae Northern
Japan solfataric spring in Noborribetsu pH
measured at 2.2 and later 0.5 in spring Optimum
Temp. 60oC Optimum pH 0.7 (0.6 molar
H) Grows well at pH 0.0 Grew only below 3.5 Max
pH 4 (if gt then lyse) Cell membrane
dissolves Cells Lyse Cytoplasm pH 4.7
(usually 7) Unique membranes that are
impermeable to H
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Cyanidinium caldarium pH 1 5.4 (opt 2)
Acidophilic, thermophilic cyanobacterium From
Yellowstone Hot Springs (Japan, Italy, Java)
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Alkaliphilic Optimum gtgtgt7 Microcystis
aeruginosa Cyano in Potomac Bacillus sp. Many
alkaliphiles some cytoplasm pH 9.5
Halobacterium halophilic and alkaliphilic
(Arch) Natronobacterium same esp alkalipilhic
(Arch) Soda lakes habitat
Natronobacterium gregoryi (Archaea)Habitat Soda
lakes Minimum tolerated 8.5, Optimum
conditions 10, Maximum12 Notes Not happy to be
just the record-holding alkaliphile, prefers to
grow in 20 NaCl
Bacillus sp. Na gradient supplies energy for
transport and motility But Proton Motive Force
is established and used for ATP synthesis HOW?
Under investigation.
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REDOX Potential Eh -log (e-) Measured by
platinum electrode redox potential 800 mV,
oxidizing - redox potential 500 mV, reducing
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Salt, Ions, Osmotic Pressure
Lots
Require salt
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Ions Na, Ca2, K, Mg2, Cations Cl-, Br-,
SO42- Anions Where Dead Sea low Na, but
high Mg B Table 13.1 Great Salt Lake - Ions like
SW, but X10 Salt Brines Salted
food Who Mostly prokaryots (few
algae) How Problem Loose water, precipitate
protein Compatible Solutes (CS) raise internal
conc. accumulate ions from outside make
organics inside CS sugars, sugar alcohols
bacteria, AA K (Archaea) glycerol algae,
yeast
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Salt Ponds SF Bay area Red pigment from
Halobacterium
Great Salt Lake
Dunaliella green alga
Lake Hamabra, Egypt
SEM of halophiles
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Protein require gtNa for activity
shape conformation Cell Wall and Membrane Na
in medium stabilizes (ltNa wall off, membrane
off) Halobacterium Mg2 stabilizes
others Ribosomes and Proteins need gt internal
K (Halobacterium) Concentrate it against
gradient Neutralizes acidic proteins Nuclear
Material like normal GC 65-68 BUT gtsalt
stabilizes DNA
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Issues Many grow fine in dH2O Many need a
little salt Vibrio cholerae Can be diagnostic
V. parahaemolyticus Question are there true
Marine Bacteria Yes require salt for life
processes
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Bologna Sandwich Experiment 1) Make Lunch 2)
Sink Alvin 3) Recover after a Year 4) Result
NO Biodegradation
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Earlier if sample deep, bring to surface,
plate Many CFUs ???in situ Jannasch and
Wirsen 1973 Ex1 - paper, balsa, ulva no
weight change, no visible growth
After 12 months
Ex2 - A) 1830 m water 1830m, 12 mo in
situ B) 1830 m water 1 ATM, 4oC, 1mo in
lab C) Surface water 1 ATM, 4oC, 1mo in lab
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I incorporation M I respiration As of 1
ATM, 4oC
EX3 -
Data expressed as of controls inc. laboratory _at_
4oC
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Pressure Effects
Terrestrial gt200 ATM inhibits 200-600 ATM
kills Marine 600 ATM grow well
Desulfovibrio barotolerant Barophiles
Spirillum, grow 15 x faster _at_ 600 ATM
vs 1 ATM Moritella opt 800 ATM from 10,000 m
Marianna Trench
slow
(1 ATM 30 fsw)
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Pressure Inhibits Protein synthesis DNA
synth RNA synth Enzyme activity By distortion
of tertiary structure Pressure likely necessary
to maintain conformation of some special
proteins e.g. ompH protein (porin) (gtP) (not
at ltP) (adapts) Cells have gt Unsat. FA less
gelling under pressure Pressure mitigates
temperature effect B. subtilis DNA _at_2000ATM,
100C, 1 hr 60 active _at_1200 ATM,
100C, 1 hr 0 active some enzymes active at
gt100C at gtgtP