This document discusses life under extreme environmental conditions and focuses on extremophiles - organisms that thrive in extreme temperatures, acidity, salinity, or other stressful conditions. It provides examples of thermophiles that live in high temperatures, psychrophiles that thrive in cold temperatures, and halophiles that survive in highly saline environments. The key adaptations that allow extremophiles to survive their extreme habitats are also summarized, such as membrane modifications, stress proteins, and organic solutes that regulate osmotic balance.

1. Life under extreme conditionsLife under extreme conditions

2. IntroductionIntroduction
Latin origin- “Extremus” means ‘Being on theLatin origin- “Extremus” means ‘Being on the
outside’ PLUS “Philos” means ‘Love’outside’ PLUS “Philos” means ‘Love’
== EXTREMOPHILEEXTREMOPHILE
Extremophile- An organism with the ability to thriveExtremophile- An organism with the ability to thrive
in extreme environments.in extreme environments.
Coined byCoined by Bob MacElroyBob MacElroy- was the biochemist in the- was the biochemist in the
Adaptation Branch in NASA Ames.Adaptation Branch in NASA Ames.

3. Extreme environments include…..
Temperature- high, low
pH- high, low
Pressure- high
Salinity- high
Nutrient concentration- low
Water availability- low
Ionizing radiation- high
Harmful heavy metals and toxic compounds- high

4. Phylogenetic tree showing Extremophiles and their resistant characteristicsPhylogenetic tree showing Extremophiles and their resistant characteristics

6. a.) Thermophilea.) Thermophile
 Organisms that can thrive in wide range of temperature.
Types-
i. Hyperthermophile: Growth >800
C
ii.Thermophile: Growth 60-800
C
iii.Mesophile: Growth 15-600
C

8. i.i. HyperthermophilesHyperthermophiles
Hyperthermophiles were first discovered by Thomas D. Brock in
1965, in hot springs in Yellowstone National Park, Wyoming.
At present- about 90 species of hyperthermophilic
archaea and bacteria are known.
Most hyperthermophilic organism –
Archea Pyrolobus fumarii- can thrive upto 1130
C.
Archea Methanopyrus kandleri- can thrive upto 1220
C
Other- Geogemma barosii (Strain 121)
Nanoarchaeum equitans, Thermus aquaticus,
Pyrococcus furiosus.
Pyrolobus fumarii,
lobed coccoid cell.
Ultrathin section.
Transmission
electron
micrograph. Scale
bar, 0.5 μm.

9. First to be identified hyperthermophile- Sulfolobus acidocaldarius, which
is both a hyperthermophile and an acidophile- found in the late 1960s in a
hot, acidic spring in Congress Pool, Norris Geyser Basin, Yellowstone
National Park, Wyoming – by Tom Brock- Average pH is 3 and Average
Temperature 800
C.

10. Hydrothermal VentsHydrothermal Vents
 Discovery in 1977- along the mid-ocean ridge in the eastern Pacific Ocean
 A hydrothermal vent forms when seawater meets hot magma
 Hydrothermal vents occur at both diverging and converging plate boundaries.
 Heat is released as magma rises and cracks the ocean floor and overlying sediments.
 Seawater drains into the fractures and becomes superheated, dissolving minerals and
concentrating sulfur and other compounds.
 The hot, mineral-rich waters then exit the oceanic crust and mix with the cool
seawater above, the dissolved minerals quickly precipitated out of solution and form
tall towers or chimneys.

11. Two types of Plumes of water stream from these waters, often rising 1,000 ft
above the vent.
i.Black smokers- emit the hottest, darkest plumes, which are high in
sulfur content and form chimneys up to 55 meters (180 feet).
ii.White smokers- lightly colored and rich in barium, calcium, and
silicon.
The temperature of the plume of white smokers is usually lower than that of
black smokers

12. • These chemosynthetic bacteria are the first step in the food chain- exist in symbiotic
relationships with species in the vent fauna- hosted by tubeworms, vent shrimps, vent
clams, and vent mussels.
• The tubeworms- no gut- depends completely on the bacteria living in their tissues.
• Clams- reduced digestive systems- indicates a greater dependence on the
chemosynthetic microbes than mussels, which have fully functional digestive systems.
The giant vent clam (Calyptogena magnica) can reach a length of nearly 8 inch.
• Also free-living chemosynthetic bacteria living at vents- Some as small blobs resembling
marine snow within the rising plume- Others grow as mats or biofilms on hard rock or
animal surfaces and are grazed by copepods, amphipods, and shrimps.
• Top carnivores at vents- the eel-like zoarchid fish and deep sea octopuses, which
apparently feeds on snails, limpets, and amphipods.

13. Hot SpringsHot Springs
 Hot springs are springs produced by the emergence of geothermally heated groundwater
that rises from the Earth's crust.
 Hot springs can be created in different ways- either be created in a volcanic or non-
volcanic manner.
 When created in an area near active volcanic zones, like Yellowstone, water becomes
heated as it comes into contact with magma. This superheated water then rises back up,
creating either a hot spring or geyser depending on the rate it rises.
 If it rises back up slowly, it will become a hot spring; if it rises back up quickly, it will
become a geyser.
 When created in non-volcanic areas, water becomes heated as it comes into contact with
hot rocks within the earth's crust. Then the water will rise back up to create hot springs.

14. Octopus Spring, an alkaline hotspring (pH 8.3-8.8) in Yellowstone National Park, USA
Water flows from Source at 950
C to an outflow channel, where it cools to a low of 830
C- Pink
filamentous Thermocrinis ruber. At 650
C- microbial mat forms with thermophilic cyanobacterium
Synechococcus on the top overlaying photosynthetic bacterium Chloroflexus.

15. ii. Thermophileii. Thermophile
Few Examples:
a)Bacillus stearothermophilus
b)Bacillus subtilis
c)Red algae Cyanidium
d)Fungus Aspergillus fumigatus

16. iii. Mesophileiii. Mesophile
Few Examples:
a)Listeria monocytogenes
b)Pseudomonas maltophilia
c)Thiobacillus novellus
d)Staphylococcus aureus
e)Streptococcus pyrogenes
f)Streptococcus pneumoniae
g)Escherichia coli
h)Clostridium botulinum.
i)Lactobacillus acidophilus

17. Adaptation mechanism of ThermophileAdaptation mechanism of Thermophile
 Membrane lipids have ether linkage- more branched, more saturated
and are of high molecular weight. These characters increase melting
temperature of membrane lipids.
• Top layer depicts the Phospholipid layer of
thermophiles- ether linkages- isoprenoid
diether or tetraether structures
• Lower layer depicts the Phospholipid layer
of other eukaryotic organisms and
bacteria- ester linkages
• Lipid bilayer labelled 9– eukaryotes and
bacteria
• Lipid monolayer labelled 10-
Thermophiles

18. Heat shock proteins- more hydrophobic interiors- prevents
unfolding or denaturation at higher temperatures
High GC content than AT content in nucleic acid structure.
Reverse DNA gyrase enzyme- catalyzes positive supercoiling
of closed circular DNA- Positively supercoiled DNA appears to
resist degradation more than negatively supercoiled DNA.
DNA association with DNA binding histone like protein.
Salts like potassium and magnesium are found at higher
levels in thermophilic archaea- protect double-stranded DNA
from phosphodiester bond degradation.

19. Thick pseudo-crystalline proteinaceous surface layer (S-
layer) surrounding cell.
Chemotrophic mode of nutrition- can live without sunlight
or organic carbon as food- instead survive on sulfur, hydrogen,
iron sulfide and other materials that other organisms cannot
metabolize.

21. b.) Psychrophile (Cryophile)b.) Psychrophile (Cryophile)
Capable of survival, growth or reproduction at temperatures of -15 °C
or lower for extended periods.
Earth is primarily a cold marine planet:
 90% of the water in the oceans has temperatures of 5 °C and;
 20% of the terrestrial region of the Earth is, glaciers and ice sheets,
polar sea ice and snow covered regions.
Desulfofrigus oceanense

22. Few Examples:
i.Psychrobacter aquaticus
ii.Pseudomonas antarctica
iii.Pseudomonas proteolytica
iv.Halomonas variabilis
v.Leifsonia aurea
vi.Kocuria polaris
vii.Sporosarcina mcmurdoensis
viii.Cyanobacteria Oscillatoria, Phormidium and Nostoc
ix.Arthrobacter flavus
•Methanogens, members of Archaea, are the only group known to be
Psychrophiles (Eg. Methanococcoides burtonii)
•A Nematode Panagrolaimus davidi- can withstand freezing of all body
water.
First to reported from Antarctica

23. Adaptation Mechanism of PsychrophileAdaptation Mechanism of Psychrophile
 Maintaining membrane fluidity- Unsaturated-cis-Fatty acid, Carotenoids- prevent
freezing.
 Cold shock proteins (CSPs) & Cold acclimatization proteins (CAPs) act as cold-
adaptive proteins in psychrophiles- small proteins that bind to RNA to preserve its
single-stranded conformation.
 Antifreeze proteins, Ice nucleating protein, and Compatible osmotic solutes- protect
from freezing.
 Proteins have a higher content of α-helix relative to the β-sheets- maintain flexibility
even at low temperatures.
 Trehalose and exopolysaccharides (EPSs)-role in cryoprotection- also prevent
protein denaturation and aggregation.

24. Physiological adaptations in a psychrophile

26. c.) Halophilec.) Halophile
Organisms that can survive in extremely salty environments.
According to the optimal salt concentration for growth-
classified in three categories:
Extreme halophile—Grows in an environment with 3.4–5.1 M
(20% to 30%) NaCl
Moderate halophile—Grows in an environment with 0.85–3.4
M (3% to 25%) NaCl
Slightly halophile—Grows in an environment with 0.2–0.85M
(1% to 5%) NaCl

27. Few Examples:
Archae
i.Halobacterium
ii.Haloarcula vallismortis
iii.Haloferax volcanii
Rotifers
i.Brachionus angularis
ii.Keratella quadrata
Algae
i.Dunaliella salina
ii.Asteromonas gracilis
Cyanobacteria
i.Aphanothece halophytica
Arthropods
i.Brine flies Ephydra hians and
E. gracillis
ii.Brine shrimp Artemia
franciscana
Protozoan
i.Fabrea salina
ii.Porodon utahensis
Bacteria
i.Chloroflexus aurautiacus
ii.Chlorobium limicola
iii.Desulfovibrio halophilus

28. Adaptation Mechanism of HalophileAdaptation Mechanism of Halophile
 If a non halophilic microbe will be
placed in a solution with a high
amount of dissolved salts- cell will
under go plasmolyzation.
 There are two strategies:
a) “Salt in” Strategy
b)“Low salt, Organic compatible
solute in” Strategy

29. “High salt in” strategy - Internal environment has a high salt
concentration- by influx of KCl- therefore organism is isotonic to its
outer environment- prevents water from moving in and out of the cell,
which regulates osmosis and maintains the structure and function of the
cell in turn.
 “Low-salt, compatible organic-solutes-in” strategy – Organisms store
organic compatible solutes (osmoprotectants) in their cells- these
organic compatible solutes regulate osmosis- are neutral or zwitterionic
include sugar, polyols, amino acids etc.
Modification of their external cell walls- tend to have negatively
charged proteins on the outside of their cell walls that stabilize it by
binding to positively charged sodium ions in their external
environments.

31. d) Barophile (Peizophile)d) Barophile (Peizophile)
Organisms that live in highly pressurized environments, such
as the bottom of the ocean.
Barotolerants (facultative): Grows at pressure from 100-400
Atm.
Barophilic (obligative): Grows at pressure greater than 400
Atm
Extreme Barophilic: Grows at pressures higher than 700 Atm

33. Adaptation Mechanism of BarophileAdaptation Mechanism of Barophile
Lipids contain Unsaturated fatty acids (PUFA)- protect from
the pressure.
Proteins coat (omps, Outer membrane proteins) -protects from
the pressure
Proteins/enzymes hold the cellular structure together by
allowing the normal chemical reactions to take place
Pressure controlled gene expression

35. e) Acidophilee) Acidophile
An organism with optimal growth at pH levels of 3 or below.
Highly acidic environments can result naturally from
geochemical activities (such as the production of sulfurous
gases in hydrothermal vents and some hot springs) and from
the metabolic activities of certain acidophiles
themselves. Acidophiles are also found in the debris left over
from coal mining.

36. Few Examples are:
1)Sulfolobus acidocaldarius
2)Hydrogenobaculum
acidophilum
3)Alicyclobacillus
acidocaldarius
4)Algae Cyanidium
caldarium

37. Adaptation Mechanism of AcidophileAdaptation Mechanism of Acidophile
Interestingly, Acidophiles cannot tolerate great acidity inside
their cells, where it would destroy important molecules as
DNA.
Sugar coating on acidophilic archaea- act as proton barrier-
apart from tetra ether linkage in monolayer lipids, there is also
high content of glycolipids, with one or more sugar units
exposed at the outer surface of the cell- Hydroxyl groups on
the sugar units prevent the protons from penetrating the cell
membrane.

39. f) Alkaliphilef) Alkaliphile
An organism with optimal growth at pH levels of 9 or above.
Few Examples:
1) Halorhodospira halochloris
2)Natronomonas pharaonis
3)Thiohalospira alkaliphila
4)Ectothirorhodospira
5)Bacillus alcalophilus
6)Bacillus subtilis
7)Bacillus pseudofirmus

40. Soda LakeSoda Lake
Saline and alkaline ecosystem.
a)Lonar crater soda lake, Maharashtra, India
b)Mono lake, US
c)Lake Magadi, Kenya
d)Big Soda Lake, US
e)Soap Lake, Central Washington

42. Adaptation Mechanism of AlkaliphileAdaptation Mechanism of Alkaliphile
Homeostasis- Internal pH maintenance is achieved by both
active and passive regulation mechanisms-
a)Passive regulation: Either by having cytoplasm rich in
amino acids with positively charged side groups (lysine,
arginine, and histidine), these cells are able to buffer their
cytoplasm in alkaline environments; or by low membrane
permeability which is another mode of passive regulation as it
ensures that fewer protons move in and out of the cell.

43. b) Active regulation: through
sodium ion channels- when there is a
build-up of Na+
in the cytoplasm, it
will be expelled in exchange for
protons (H+
)
 Presence pH stable enzymes in alkaliphilic organisms.
 In addition to peptidoglycan, cell wall contain certain acidic
polymers, such as galacturonic acid, gluconic acid, glutamic acid,
aspartic acid, and phosphoric acid. The negative charges on these
acidic nonpeptidoglycan components may give the cell surface its
ability to adsorb sodium and hydronium ions and repulse hydroxide
ions and, as a consequence, may assist cells to grow in alkaline
environments.

45. g) Radioresistorg) Radioresistor
Organisms resistant to high levels of ionizing radiation, most
commonly UV radiation.
Some capable of resisting nuclear radiation.

46. Amoeba (1000 Gy)
Thermococcus gammatolerans
(most radioresistant organism)
(30,000 Gy)
Deinococcus radiodurans*
(15,000 Gy)
Milnesium tardigradum
(Water Bear)
(5000 Gy)
Wasp (1,800 Gy)
Cockroach (100-9000 Gy)

47. Adaptation Mechanism of World’s toughestAdaptation Mechanism of World’s toughest
BacteriumBacterium (Deinococcus radiodurans)
Deinococcus radiodurans listed as the the world's toughest
bacterium in The Guinness Book of World Records, and is
nicknamed Conan the Bacterium.
The bacterium name means “Strange berry that withstands
radiation”
It has from four to ten DNA molecules compared to only one for
most other bacteria.
DNA repair enzymes-RecA protein- matches the broken pieces of
DNA and splices them back together just in few hours.

48. Some other Types of ExtremophilesSome other Types of Extremophiles
a) Xerophile: Can grow in extremely dry, desiccating conditions.
Examples- Trichosporonoides nigrescens
b) Toxitolerant: Withstand high levels of damaging agents such
as Benzene. Examples- Pseudomonas putida
c) Metallotolerant: can tolerate high levels of dissolved heavy
metals in solution. Examples- Ferroplasma sp., Cupriavidus
metallidurans
d) Osmophile: Can grow in environments with a high sugar
concentration. Examples- Zygosaccharomyces rouxii

49. Boil them, deep-freeze them,
crush them, dry them out or
blast them into space:
tardigrades will survive it all
and come back for more!!

50.  Discovered in 1773 by a German pastor named Johann August Ephraim Goeze
 Microscopic animals - body size varies from0.05 to 1.2 mm.
 Caterpillar like creature with eight legs and it has claws which looks like bear claws.
Therefore it is commonly known as Water BearWater Bear.
 Can survive all extreme environments:
a) 120 to 1500
C high temperature
b) 200 to 3000
below 00
C
c) 1000 atm high pressure
d) Vacuum of space
e) Xrays, UV rays
 In the active stage (during crawling around, eating and reproducing)-not tougher
than any other animal- But when conditions worsen- dry or
freeze called cryptobiosis (or anabiosis)- look like they are dead - they don't eat,
don't move, and don't breath- "dead but still alive”- water is replaced with
trehalose (a non-reducing sugar) in order to prevent cellular destruction due to water
freezing in their cells.

51. Hyper thermophiles
(sources)
uses
DNA polymerases DNA amplification by PCR
Alkaline phosphatases diagnostics
Proteases and lipases Dairy products
Lipases and proteases Detergents
Proteases Baking, brewing, amino acid production from keratin
Alcohol dehydrogenase Chemical synthesis
Xylanases Paper bleaching

52. Hyper thermophiles uses
S-layer proteins and lipids Molecular sieves
Lenthionin pharmaceutical
Oil degrading microorganisms Surfactants for oil recovery
Sulfur oxidizing microorganisms Bioleaching, coal & waste gas desulfurization
Hyperthermophilic consortia Waste treatment and methane production

53. Psychrophiles (source) Uses
Alkaline phosphatase Molecular biology
Lipases and proteases Cheese manufacture and dairy production
Proteases Contact-lens cleaning solutions, meat tenderizing
Polyunsaturated fatty acids Food additives, dietary supplements
Proteases, lipases, cellulases and amylases Detergents

54. Psychrophiles Uses
Methanogens Methane production
Various enzymes Modifying flavors
b-galactosidase Lactose hydrolysis in milk products
Ice nucleating proteins
Artificial snow, ice cream, other freezing
applications in the food industry
Various enzymes (e.g. dehydrogenases) Biotransformations
Various enzymes (e.g. oxidases)
Bioremediation,environmental
biosensors

55. Halophiles (source) Uses
Bacteriorhodopsin Optical switches and photocurrent
generators in bioelectronics
Polyhydroxyalkanoates Medical plastics
Rheological polymers Oil recovery
Eukaryotic homologues (e.g. myc oncogene
product)
Cancer detection, screening anti-tumor
drugs
Lipids Liposomes for drug delivery and cosmetic
packaging
Compatible solutes Protein and cell protectants in variety of
industrial uses, e.g. freezing, heating
Membranes Surfactants for pharmaceuticals

56. Halophiles Uses
Compatible solutes Protein and cell protectants in variety of
industrial uses, e.g. freezing, heating
nucleases, amylases, proteases Various industrial uses, e.g. flavoring
agents
g-linoleic acid, b-carotene and cell
extracts, e.g. Spirulina and Dunaliella
Health foods, dietary supplements, food
coloring and feedstock
Microorganisms Fermenting fish sauces and modifying food
textures and flavors
Microorganisms Waste transformation and degradation,
e.g. hypersaline waste brines
contaminated with a wide range of
organics

57. Alkaliphiles (source) uses
Proteases Gelatin removal on X-ray film
Proteases, cellulases, xylanases, lipases and
pullulanases
Detergents
Elastases, keritinases Hide dehairing
Cyclodextrins Foodstuffs, chemicals and pharmaceuticals
Xylanases and proteases Pulp bleaching
Pectinases Fine papers, waste treatment and degumming
Alkaliphilic halophiles Oil recovery

58. Acidophiles (source) Uses
Sulfur oxidizing microorganisms
Recovery of metals and desulfurication of
coal
Microorganisms Organic acids and solvents