Transcript
Background
Biologists have long organized living things into large groups called kingdoms.
There are six of them:◦ Archaebacteria
◦ Eubacteria
◦ Protista
◦ Fungi
◦ Plantae
◦ Animalia
Some recent findings… In 1996, scientists decided to split Monera
into two groups of bacteria:Archaebacteria and Eubacteria
Because these two groups of bacteria were different in many ways scientists created a new level of classification called a DOMAIN.
Now we have 3 domains1. Bacteria2. Archaea3. Eukarya
KingdomArchaebacteria
Any of a large group of primitive bacteria having unusual cell walls, membrane lipids, ribosomes, and RNA sequences, and having the ability to produce methane and to live in anaerobic, extremely hot, salty, or acidic conditions
The Domain Archaea
“ancient” bacteria Some of the first
archaebacteria were discovered in Yellowstone National Park’s hot springs
Prokaryotes are structurally simple, but biochemically complex
Basic Facts They live in extreme environments (like hot
springs or salty lakes) and normal environments (like soil and ocean water).
All are unicellular (each individual is only one cell).
No peptidoglycan in their cell wall.
Some have a flagella that aids in their locomotion.
Most don’t need oxygen to survive They can produce ATP (energy) from
sunlight They can survive enormous temperature
extremes They can survive under rocks and in ocean
floor vents deep below the ocean’s surface
They can tolerate huge pressure differences
STRUCTURE
Size Archaea are slightly less than 1 micron long.
A micron is 1/1,000 of a millimeter.
In order to see their cellular features, scientists use powerful electron microscopes.
Shape• Shapes can be spherical or ball shaped and are called
coccus.
• Others are rod shaped, long and thin, and labeled bacillus.
• Variations of cells have been discovered in square and triangular shapes.
STRUCTURELocomotion• Some archaea have flagella, hair-like structures that assist in
movement.
• There can be one or many attached to the cell's outer membrane. Protein networks can also be found on the cell membrane, which allow cells to attach themselves in groups.
Cell Features• Within the cell membrane, the archaea cell contains
cytoplasm and DNA, which are in single-looped forms called plasmids.
• Most archaeal cells also have a semi-rigid cell wall that helps it to maintain its shape and chemical balance.
• This protects the cytoplasm, which is the semi-liquid gel that fills the cell and enables the various parts to function.
STRUCTURE
Phospholipids The molecules that make up cell membranes are called
phospholipids, which act as building blocks for the cell.
In archaea, these molecules are made of glycerol-ether lipids.
Ether Bonding The ether bonding makes it possible for archaea to
survive in environments that are extremely acidic or alkaline, or that have great extremes in temperature.
CLASSIFICATION
FIVE PHYLUMS1. Crenarchaeota
2. Euryarchaeota
3. Korarchaeota
4. Thuamarchaeota
5. Nanoarchaeota
CRENARCHEOTA• The name Crenarchaeota means “scalloped
archaea.” they are often irregular in shape
•All crenarchaeotes synthesize a distinctivetetraether lipid, called crenarchaeol. Originallycontaining thermophylic & hyperthermophilic sulfurmetabolizing archaea.•Recently discovered Crenarchaeota are inhibitedby sulfur & grow at lower temperatures.•These organisms stain Gram negative & aremorphologically diverse having rod, cocci,filamentous & oddly shaped cells
Example s:-
One of the best characterized members of the Crenarcheota is Sulfolobus solfataricus, isolated from geothermally heated sulfuric springs in Italy & grows at 80 °C & pH of 2–4
Othwer examples are Pyrolobus fumarii ,
Sulfolobus solfataricus and Sulfolobusacidocaldarius
Phylum Euryarchaeota
Very diverse with 7 classes
. Methanococcus, Methanobacteria, Halobacteria, Thermoplasmata, Thermococci, Archaeglobi & Methanopyri
Consists of 9 orders & 15 families
On the basis of habitat they are divided into the followings
methanogens,
extreme halophiles,
sulphate reducers & many extreme thermophileswith S dependent metabolism
Halophiles :- Halo = salt
phil = loving The halophilic organisms require salty environment for
survival Occurance :-they are found in salts lakes & areas where
evaporation of sea water occurs such as the Great SaltLake in the U.S. and the Dead Sea.
Can live in water with salt concentrations exceeding 15% The ocean’s concentration is roughly 4% Example:- Halobacterium which includes several
species, found in salt lakes & high salineoceanenvironments.
Halobacterium salinarum, H. denitrificans & H. halobium
The Great Salt Lake in Utah
Methanogens Methanogens are microorganisms that produce methane as
a metabolic byproduct in anoxic conditions.. They are strictly anaerobic organisms & are killed when
exposed to O2. They reduce CO2 using H2 & release CH4 inswamps & marshes that is called marsh gas.
Occurance :- Many live in mud at the bottom of lakes and swamps
because it lacks oxygen They are also found in the gut of some herbivores like
cows , humans dead & decaying matter. Importance :- They are added to biogas reactors for production of CH4
gas for cooking & sewage treatment plants. Examples :- Methanofollis aquaemaris, M. ethanolicus, M. formosanus,
M. liminatans
Thermophilic & Sulfur-reducing archaea
All thermophiles require hot water but differ in otherhabitat needs.
Some thrive in only acidic water, others require sulphuror calcium carbonate & others live in alkaline springs.
Depending on characteristics which it may possess, Theycan be described with more specific terms such as
Thermoacidophile (heat and acid lover) they have bothaerobic and anaerobic species.
Hyperthermophile (extreme heat lover).
Pyrolobus fumarii, currently holds the record for high-temperature growth, it can grown in temperatures up to113oC.
They live in hot springs (pools of hot water that have moved toward earth's surface)
Halophilic bacterium
Methanogenic archeabacteria
Thermophilic
KORARCHAEOTA
The name is derived from the Greek noun korosor kore, meaning ‘‘young man’’ or ‘‘young woman,’’ and the Greek adjective archaios which means ‘‘ancient.’’ They are also known as Xenarchaeota.The Korarchaeota have only been found in high temperature hydrothermal environments. In Yellowstone National Park (YNP), Korarchaeota were most abundant in springs with a pH range of 5.7 to 7.0The Korarchaeota were originally discovered by microbial community analysis of ribosomal RNA genes from environmental samples of a hot spring in Yellowstone National Park.
THAUMARCHAEOTA The Thaumarchaeota (from the Greek 'thaumas',
meaning wonder) are proposed in 2008 after the genome of C.symbiosum was sequenced and found to differ significantly from other members of phylum Crenarchaeota. All organisms of this lineage thus far identified are chemolithoautotrophic ammonia-oxidizers and may play important roles in biogeochemical cycles, such as the nitrogen cycle and the carbon cycle.
It was promosed on basis of phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes.
NANOARCHAEOTAIn taxonomy, the Nanoarchaeota from Greek meaning "old dwarf“.
They inhabit high-temperature environments with an optimal growth of 90 C; and are highly unusual because they grow and divide on the surface of another archaea, Ignicoccus. Nanoarchaea, which were discovered in 2002, contain both the smallest known living cell (1/100th the size of Escherichia coli) and the smallest known genome (480 kilobases [1 kilobase = 1,000 base pairs of DNA]; . Members of this phyla have not been detected in pure culture.
Cells of Nanoarchaeum are about 0.4 μm in diameter and replicate only when attached to the surface of Ignicoccus.
Exthermophilic enzymes:Exthermophilic Archae
Resistant to either to heat or to extremes of acidity and alkalinity
Uses
Thermostable DNA polymerases, such as the PfuDNA polymerase from Pyrococcus furiosus areused in PCR.
amylases, galactosidases and pullulanases inother species of Pyrococcus that function at over100 °C allow food processing at high temperature.
Sewage Treatment: Methanogenic Archae
They carry out anaerobic digestion and produce biogas
Extraction of Metals:
Acidophilic Archae
Extract gold,copper and cobalt from their ores.
Methane Gas Production:
Methanogenic Archae
can decomposgrow in biogas fermentors e cow dung into methane gas as a by-product.
Role in chemical cycles:
Play important role in carbon cycle,nitrogen cycle, sulphur cycle etc.
Help in reasearches:
Their ability to tolerate extreme conditions helps researchers learn about the climatic conditions, environment and their survival on ancient earth.
Anti-biotics:
Archaea host a new class of potentially useful antibiotics.
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