Extremophiles are microorganisms which have adapted so that they can survive and
even thrive in conditions that are normally fatal to most life-forms.
For example, some species have been found in the following extreme
environments:
Temperature:
as high as 130 °C (266 °F),as low as −17 °C (1 °F)
Acidity/alkalinity:
less than pH 0, up to pH 11.5
Salinity:
up to saturation
Pressure:
up to 1,000-2,000 atm, down to 0 atm (e.g. vacuum of space)
Radiation:
up to 5kGy
Extremophiles are significant in different ways.
They extend terrestrial life into much of the Earth's hydrosphere, crust and atmosphere,
their specific evolutionary adaptation mechanisms to their extreme environment can be
exploited in bio-technology, and their very existence under such extreme conditions
increases the potential for extraterrestrial life.
• Grow at o °c.
• Optimum temperature 15 °c or
lower.
• Maximum 20 °c
Habitats :Isolated Artic and Antartic habitats.
(90% of the ocean is 5°C or colder)
Examples :• Arthrobacter sp.,
• Psychrobacter sp.
PSYCHROTROPHS:
• Legionella.
Psychrophiles
Halophiles can be found anywhere with a concentration of
salt five times greater than the salt concentration of the
ocean,
• Great Salt Lake (Utah)
• Owens Lake (California)
• Dead Sea,
• Evaporation Ponds.
Halobacterium sp. strain NRC-1, each cell
about 5 μm in length.
• Adapted extreme hypertonic environment.
• Grow optimally,Presents of Nacl or other salts.
• Sea water contain 35% mixes with fresh water- nearly 0%.
• E.x:
Halobacterium.
Halococcus
Halobacterium- Halococcus.
Phylum: Extreme
Halobacterium
Halobacterium sp. strain NRC-1, each cell about 5 μm in length.
Domain:
Kingdom:
Scientific classification
Archaea
Euryarchaeota
Phylum:
Euryarchaeota
Class:
Order:
Halobacteria
Halobacteriales
Family:
Halobacteriaceae
Genus:
Halobacterium
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H. jilantaiense
H. noricense
H. salinarum
H. piscisalsi
Binomial name
Halobacterium
Elazari-Volcani 1957
Species
In taxonomy, Halobacterium is a genus of
the Halobacteriaceae
Domain:
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
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Halococcus
Scientific classification
Archaea
Euryarchaeota
Euryarchaeota
Halobacteria
Halobacteriales
Halobacteriaceae
Halococcus
Binomial name
Halococcus Schoop 1935
Species
H. dombrowskii
H. hamelinii
H. morrhuae
H. qingdaogense
H. saccharolyticus
H. salifodinae
H. thailandensis
Halococcus is a genus of
the Halobacteriaceae.
• Adapted completely hypertonic saline condition
• Require high level Nacl
Salinity:
It is remarkably constant throughout the deep sea.
Some minor differences in salinity, but none that are
ecologically significant, except in the Mediterranean
& Red seas.
• Below the thermocline, the water mass of the deep
ocean is cold and far more homogeneous.
• temperature of the epipelagic zone, is above 20°C.
• based on the epipelagic, it drops over several
hundred meters to 5 or 6°C at 1,000 meters.
• Affects growth of microbs
• High temperature damages microbes by denaturing
enzymes ,transport carriers and other proteins
• Microorganisms can placed in 5 clanes based on
temperature ranges
THERMOPHILES:
Grow at 55 ° c or higher.
Minimum -45 ° c .
Optimum-55 c to 65 °c.
• Present in a planet’s surface from which
Geothermally “Heated Water Issues”.
• Commonly found near volcanically active places,
ocean basins & hotspots.
A colony of thermophiles in the
outflow of Mickey Hot Springs,
• It forms some features in under the sea called Oregon,
“Black Smokers”.
the water temperature is
approximately 60°C.
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HYPERTHERMOPHILES:
Grow at 90°c.
Maxima above 100°c.
Don ‘t grow below 55 °c.Microorganisms in deep-sea
hydrothermal plumes:• Hydrothermal vents vary considerably, from relatively
low-temperature (<25 °C) fluid discharges to the
spectacular high-temperature (~350 °C)
• black smokers1–3.
• The high-temperature vents give rise to buoyant plumes
which can be detected hundreds of kilometres away
from ridge crests4,5.
BLACK SMOKERS:
It found on sea bed, typically in the
abyssal & hadal zones.
In the immediate vicinity of hydrothermal
vents,
chemoautotrophic bacteria are present
in vent fluids,
attached to rock surfaces9,10, and as
endosymbionts in certain macro fauna11
WHITE SMOKERS:
• Contain barium, calcium & silicon.
• Vent organism depend on chemosynthetic
bacteria for food.
• It contains huge number of bacteria.
PRESSURE:
Prokaryotes live in deep sea.
Hydrostatic pressure -600 to 1100 atm and temperature -2 to 3 °c.
Greatest environmental factors acting on deep sea organism.
it increases 1 atmosphere (atm) for each 10 m in depth.
In deep sea is under pressures between 200 and 600 atm, the range of pressure
is from 20 to 1,000 atm.
Microbes live on land or surface water – 1atm
Can play a major role in nutrient recycling in deep sea.
E.g : Photobacterium ,
Shewanella.
• Existing below the “thermocline” & above seabed.
• It is very icy and dark at the bottom.
• Sunlight can’t reach there but most of the deep sea produced
light that can be seen easily in dark
• deep sea or deep layer in the ocean existing below the
thermoline and allow the seabed depth of 1000 or more
• Most organisms falling organic matter produced in the photic
zone
Definition:
Nitrification is the biological oxidation of ammonia with oxygen
into nitrite followed by the oxidation of these nitrites into nitrates.
Nitrification in the marine environment:
• In the marine environment, nitrogen is often the limiting nutrient
• The nitrification step of the cycle is of particular interest in the ocean
because it creates nitrate, the primary form of nitrogen responsible
for “new” production.
• Furthermore, as the ocean becomes enriched in anthropogenic CO2, the
resulting decrease in pH could lead to decreasing rates of nitrification.
Nitrification as stated above is formally a two-step process.
First Step :
ammonia is oxidized to nitrite,
Nitrification is a process of nitrogen compound oxidation :
NH3 + 11/2 O2 + Nitrosomonas -------→ NO2- + H2O + H+
NO2- + 1/2O2 + Nitrobacter ------------→ NO3-
NH3 + O2 -----------------------------------→ NO2− + 3H+ + 2e−
NO2− + H2O ------------------------------→ NO3− + 2H+ + 2e−
Second Step :
nitrite is oxidized to nitrate.
Different microbes are responsible for each step in the marine environment.
Several groups of ammonia oxidizing bacteria (AOB) are known in the
marine environment
Example::Bacteria :Nitrosomonas,
Nitrospira, and
Nitrosococcus.
Nitrospina and
Nitrobacter are known to carry out this step in the ocean.
All contain the functional gene ammonia monooxygenase (AMO) which, as
its name implies, is responsible for the oxidation of ammonia.
Definition:Denitrification is a microbially facilitated process of nitrate
reduction that may ultimately produce molecular nitrogen (N2)
through a series of intermediate gaseous nitrogen oxide products.
Measurement:denitrification rates were measured in sediment cores from a
MARINE of the Chesapeake Bay using high precision membrane
inlet mass spectrometry.
Denitrification was independent of salinity over the range of 1-13
ppt and directly dependent on nitrate concentration over the range
of 0-200 µM in the overlying water.
Denitrification was observed when the water colunm nitrate
concentration was <1 µM, indicating that nitrification in the
sediments was occurring.
4KNO3+502---------- 2K2 O + 2N2
molecules of oxygen are consumed for each molecule of
nitrogen
evolved, but the amount of oxygen liberated at each stage
is different:
1. Nitrate to nitrite.
2KNO3+ 02 - --- + 2KNO2
(ii) Nitrite to hyponitrite.
2KNO2+ 02 -- -- +2 KN202.
(iii) Hyponitrite to nitrogen.
2K2N202 + 02 - -- + 2K2O + 2N2
• Methanogenesis or biomethanation is the
formation of methane by microbes known
as methanogens.
• Organisms capable of producing methane have
been identified only from the kingdom Archaea, a
group phylogenetically distinct from
both eukaryotes and bacteria, although many live
in close association with anaerobic bacteria.
• The production of methane is an important and
widespread form of microbial metabolism.
• In most environments, it is the final step in the
decomposition of biomass.
Strains of methanogens
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Methanobacterium bryantii
Methanobacterium formicum
Methanobrevibacter arboriphilicus
Methanobrevibacter gottschalkii
Methanobrevibacter ruminantium
Methanobrevibacter smithii
Methanocalculus chunghsingensis
Methanococcoides burtonii
Methanococcus aeolicus
Methanococcus deltae
Methanococcus jannaschii
Methanococcus maripaludis
Methanococcus vannielii
Methanocorpusculum labreanum
Methanoculleus bourgensis
(Methanogenium olentangyi &
Methanogenium bourgense)
Methanoculleus marisnigri
Methanofollis liminatans
Methanogenium cariaci
Methanogenium frigidum
Methanogenium organophilum
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Methanogenium wolfei
Methanomicrobium mobile
Methanopyrus kandleri
Methanoregula boonei
Methanosaeta concilii
Methanosaeta thermophila
Methanosarcina acetivorans
Methanosarcina barkeri
Methanosarcina mazei
Methanosphaera stadtmanae
Methanospirillium hungatei
Methanothermobacter defluvii
(Methanobacterium defluvii)
Methanothermobacter thermautotrophicus
(Methanobacterium thermoautotrophicum)
Methanothermobacter thermoflexus
(Methanobacterium thermoflexum)
Methanothermobacter wolfei
(Methanobacterium wolfei)
Methanothrix sochngenii
Ammonification:
When a marine plant or animal dies, or an animal expels waste, the initial form of nitrogen
is organic. Bacteria, or fungi in some cases, convert the organic nitrogen within the
remains back into ammonium (NH4+), a process called ammonification or mineralization.
Enzymes Involved:
GS: Gln Synthetase (Cytosolic & PLastid)
GOGAT: Glu 2-oxoglutarate aminotransferase (Ferredoxin & NADH dependent)
GDH: Glu Dehydrogenase:
Minor Role in ammonium assimilation.
Important in amino acid catabolism.
cycle
• Sulfur is one of theSulfur
constituents
of many proteins,
vitamins and hormones. It recycles as in other
biogeochemical cycles.
• The essential steps of the sulfur cycle are:
• Mineralization of organic sulfur to the inorganic form,
hydrogen sulfide: (H2S).
• Oxidation of sulfide and elemental sulfur (S) and related
compounds to sulfate.
• Reduction of sulfate to sulfide.
• Microbial immobilization of the sulfur compounds and
subsequent incorporation into the organic form of sulfur.
Dimethylsulfoniopropionate (DMSP):-
Formula:(CH3)2S+CH2CH2COO−.
This zwitterionic metabolitefound :Marine Phytoplankton,
Seaweeds,
Species Of Terrestrial And
Aquatic Vascular Plants.
Functions:Osmolyte
Physiological and
environmental roles.
Degradation:DMSP is broken down by marine microbes to form two major volatile sulfur
products.
Ismethanethiol (CH3SH),
Dimethyl Sulfide (CH3SCH3; DMS).
Its major breakdown product Ismethanethiol (CH3SH), assimilated by bacteria
into protein sulfur.
Its second volatile breakdown product :Dimethyl Sulfide (CH3SCH3; DMS)
DMSP DMSP lyase DMS
Most DMS in seawater is cleaved from DMSP by the enzyme DMSP lyase, although
many non-marine species of bacteria convert methanethiol to DMS
DMS is also taken up by marine bacteria, but not as rapidly as methanethiol.
Although DMS usually consists of less than 25% of the volatile breakdown products of
DMSP, the high reactivity of methanethiol makes the steady-state DMS concentrations in
seawater approximately 10 times those of methanethiol (~3 nM vs. ~0.3 nM).
Curiously, there have never been any published correlations between the concentrations
of DMS and methanethiol.
This is probably due to the non-linear abiotic and microbial uptake of methanethiol in
seawater, and the comparatively low reactivity of DMS.
However, a significant portion of DMS in seawater is oxidized to dimethyl
sulfoxide (DMSO).
Relevant to global climate, DMS is thought to play a role in the Earth's heat budget by
decreasing the amount of solar radiation that reaches the Earth's surface.
DMSP has also been implicated in influencing the taste and odour characteristics of
various products.
For example:DMSP is odourless and tasteless,
it is accumulated at high levels in some marineherbivores or filter feeders.
Increased growth rates, vigour and stress resistance among animals cultivated on such
diets have been reported.
DMS, is responsible for repellent, 'off' tastes and odours that develop in some seafood
products because of the action of bacterial DMSP-lyase, which cogenerates acrylate.
Formula:- (CH3)2SO
• This colorless liquid is an important polar aprotic solvent that dissolves both polar and
nonpolar compounds and is miscible in a wide range of organic solvents
• organosulfur compound
• It penetrates the skin very readily, giving it the unusual property for many individuals
of being secreted onto the surface of the tongue after contact with the skin and
causing a garlic-like taste in the mouth.
Synthesis and production:• It was first synthesized in 1866 by the Russian scientist Alexander Zaytsev
• Oxidation of dimethyl sulfide with oxygen or nitrogen dioxide gives DMSO
Biological Use:• DMSO is used in PCR to inhibit secondary structures in the DNA template or the DNA
primers.
• It is added to the PCR mix before reacting, where it interferes with the selfcomplementarity of the DNA, minimizing interfering reactions.
• DMSO may also be used as a cryoprotectant, added to cell media to prevent cell
death during the freezing process.
Medicine:Use of DMSO in medicine dates from around 1963, when an Oregon Health & Science
University Medical School team, headed by Stanley Jacob, discovered it could penetrate
the skin and other membranes without damaging them and could carry other compounds
into a biological system.
In medicine, DMSO is predominantly used as a topical analgesic, a vehicle for topical
application of pharmaceuticals, as an anti-inflammatory, and an antioxidant.
Because DMSO increases the rate of absorption of some compounds through
organic tissues, including skin, it can be used as a drug delivery system.
It is frequently compounded with antifungal medications, enabling them to penetrate not
just skin but also toe and fingernails.
Veterinary medicine:DMSO is commonly used in veterinary medicine as a liniment for horses, alone or in
combination with other ingredients. In the latter case, often, the intended function of the
DMSO is as a solvent, to carry the other ingredients across the skin.
Also in horses, DMSO is used intravenously, again alone or in combination with other
drugs. It is used alone for the treatment of increased intracranial pressure and/or cerebral
edema in horses.
In cryobiology DMSO has been used as a cryoprotectant and is still an important
constituent of cryoprotectant vitrification mixtures used to preserve organs, tissues, and
cell suspensions. Without it, up to 90% of frozen cells will become inactive.
It is particularly important in the freezing and long-term storage of embryonic stem
cellsand hematopoietic stem cells, which are often frozen in a mixture of 10% DMSO,
Media and 30% fetal bovine serum.
In the cryogenic freezing of heteroploid cell lines (MDCK, VERO, etc.) a mixture of 10%
DMSO with 90% EMEM (70% EMEM + 30% fetal bovine serum + antibiotic mixture) is
used.
As part of an autologous bone marrow transplant the DMSO is re-infused along with the
patient's own hematopoietic stem cells.
In a 1978 study at the Cleveland Clinic Foundation in Cleveland, Ohio, researchers
concluded that DMSO brought significant relief to the majority of the 213 patients with
inflammatory genitourinary disorders that were studied.
They recommended DMSO for all inflammatory conditions not caused by infection or
tumor in which symptoms were severe or patients failed to respond to conventional
therapy.
DMSO has been examined for the treatment of numerous conditions and ailments, but
the U.S. Food and Drug Administration (FDA) has approved its use only for the
symptomatic relief of patients with interstitial cystitis.
In interventional radiology, DMSO is used as a solvent for Ethylene Vinyl Alcohol in
the Onyx liquid embolic agent, which is used in embolisation, the therapeutic occlusion of
blood vessels.
Safety:DMSO by itself has low toxicity.
DMSO's use in reducing brain tissue swelling following traumatic brain injury.
DMSO exposure to developing mouse brains can produce brain degeneration.
This neurotoxicity could be detected at doses as low as 0.3 mL/kg, a level exceeded in
children exposed to DMSO during certain medical treatments.
Glove selection is important when working with DMSO. Thick rubber gloves are
ecommended.
Nitrile gloves, which are very commonly used in chemical laboratories, have been found to
dissolve rapidly with exposure to DMSO.
Because DMSO easily penetrates the skin, substances dissolved in DMSO may be quickly
absorbed.
For instance, a solution of sodium cyanide in DMSO can cause cyanide poisoning through
skin contact. it contains
Dimethyl sulfoxide can produce an explosive reaction when exposed to acyl
chlorides; at a low temperature, this reaction produces the oxidant for Swern
oxidation.
DMSO disposed into sewers can also cause odor problems in municipal effluents:
waste water bacteria transform DMSO under hypoxic (anoxic) conditions
into dimethyl sulfide (DMS) that has a strong disagreeable odor, similar to rotten
cabbage.[20] However, chemically pure DMSO is odorless because of the lack of
C-S-C (sulfide) and C-S-H (mercaptan) linkages.
Deodorization of DMSO is achieved by removing the odorous impurities
Marine Microbiology- 2Mark
Questions
Explain ammonification process
Is the process by which the organically bound nitrogen of
microbial, plant, and animal biomass is recycled after their
death. Ammonification is carried out by a diverse array of
microorganisms that perform ecological decay services,
and its product is ammonia or ammonium ion.
Dimethyl Sulfonio Propionate (DMSP)
Is a zwitterionic metabolite found in marine phytoplankton,
seaweeds and some species of terrestrial and aquatic
vascular plants.
DMSP is broken down by marine microbes to form two
major volatile sulfur products, each with distinct effects on
the environment. Its major breakdown product is
methanethiol (CH3SH) which is assimilated by bacteria into
protein sulfur.
Dimethyl Sulfoxide (DMSO)
• Is an abundant but poorly understood methylated sulfur
compound in the marine environment. One potentially
significant loss pathway for DMSO is through its
biological reduction to dimethylsulfide (DMS), which has
been documented in a number of organisms, most
notably bacteria.
Nitrogen cycle
• The nitrogen cycle is the process by which nitrogen is
converted between its various chemical forms. This
transformation can be carried out via both biological and
non-biological processes. Important processes in the
nitrogen cycle include fixation, mineralization,
nitrification, and denitrification.
cycle
• Sulfur is one of theSulfur
constituents
of many proteins,
vitamins and hormones. It recycles as in other
biogeochemical cycles.
The essential steps of the sulfur cycle are:
• Mineralization of organic sulfur to the inorganic form,
hydrogen sulfide: (H2S).
• Oxidation of sulfide and elemental sulfur (S) and related
compounds to sulfate.
• Reduction of sulfate to sulfide.
• Microbial immobilization of the sulfur compounds and
subsequent incorporation into the organic form of sulfur.
Organisms that can fix atmospheric
nitrogen
• Free living bacteria: Aerobic (Azotobacter, Klebsiella);
Anaerobic (Desulfovibrio, some
• Clostridium species)
• Cyanobacteria: (Nostoc common in lichen)
• Symbionts = live in symbiosis with certain plants :with
legumes (Rhizobium); with other plants (Frankia,
Azospirillium)
REFERENCES:
• Net reference.