new microsoft power point presentation_2
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A M Grouppresents
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Kingdom:Bacteria
Phylum :Deinococcus-Thermus
Order :Deinococcales
Genus :Deinococcus
There are 42 species ofDeinococcus described.
Initially it was placedin the genus Micrococcus. Deinococcus,is closely related to the genus
Thermus of heat-resistant bacteria.
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Deinococcus radiodurans
unusual grain radiation surviving
THE CONAN OF BACTERIA
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First appearedin the 1950s in canned
meat that hadbeen experimentally
irradiated as means of preservative.
The complete DNA sequence ofD.
radiodurans was publishedin 1999 by
TIGR. A detailed annotation and analysis
of the genome appearedin 2001
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a mesophile, 30-37C (Growth ceases attemperatures below 4C and above 45C.(
Colonies are smooth, convex, and pink to redin
colordue to carotenoid pigment Deinoxhantin
grows as clusters of two cells (diplococci)in the
early stages ofgrowth,
and as clusters of four cells (tetracocci)in the late
stages ofgrowth,
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yourname
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yourname
plasma membrane
peptidoglycan layer
the holey layer
compartmentalized layer
plasma membrane
topped with an
electrolucent zone
S-layer
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has been foundin a wide variety ofenvironments which therefore make its naturalhabitat difficult to define) live everywhere andnowhere ).
from locations rich in organic nutrients,includingsoil, animal faeces, and processed meats, aswell as from dry,nutrient-poor environments,including weatheredgranite in a dry Antarcticvalley, room dust, andirradiated medicalinstruments
There is no current findings that suggest that D.radiodurans significantly interacts with other
organisms innature
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grown with aerationinTGY broth
(0.5% Tryptone, 0.1% Glucose, 0.3% Yeast extract)
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capable of withstanding an acute dose of 5,000 Gy ofionizing radiation with almost no loss of viability, and anacute dose of 15,000 Gy with 37% viability
A dose of 5,000 Gy is estimated to introduce several
hundreddouble strandbreaks (DSBs)into theorganism's DNA
5 Gy cankill a human, 200-800 Gy will kill E. coli.
Representative survival curve for
D. radiodurans R1 (squares) and
forE. coli
(diamonds) following exposure to
UV radiation
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while 5 units ofgamma radiationis lethal
to humans and 2,000 units ofgamma
radiationis enough to stop all cell activity
for E. Coli, D. radiodurans canbe exposed
to 10,000 units ofgamma radiation without
dying or mutating
Representative survival curve
forD. radiodurans R1 (squares)
and forE. coliB/r
(diamonds) following exposure
to radiation.
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it can survive for six years in a desiccatorwith 10% viability
there is connectionbetween the ionizingradiation resistance ofD. radiodurans andits desiccation resistance.
It can survive cold,dehydration, vacuum,andacid, andis therefore known as apolyextremophile
and has been listed as
the world's toughest bacterium in
The Guinness Book Of World Records
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Ultraviolet ( UV ) light is electromagnetic
radiation with a wavelength shorter than that of
visible light,but longer thanX-rays,in the range
10 nm to 400 nm.
so namedbecause the spectrum consists of
electromagnetic waves with frequencies higher
than those that humansidentify as the color
violet (. the shortest wavelengths of visible light )
. UV light powers vitamin D productionin the
skin
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Ultraviolet photons harm the DNA moleculesof living organisms indifferent ways.In one
commondamage event, adjacent thymine
bases bond with each other(,instead ofacross the "ladder". This" thymine dimer"
makes a bulge, and the distorted DNA
molecule does not function properly
commoninvolves adjacent bases bonding
with each otherinstead of their partners on
the other side of the DNA ladder
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The genome ofD. radiodurans R1 strain
consists of four major parts: two circular chromosomes (2,648,638 and 412,348
base pairs (,
a major plasmid (177,466 base pairs (,
and a small plasmid (45,704 base pairs .(
No current research shows whether ornot these
plasmids contribute specifically to functionality or
virulence.
a highGCcontent, ranging from 65 to 71 mol%.
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DNA inD. radiodurans is organizedinto tightlypackedtoroids, which may facilitate DNA repair
that the tightly structured, ring-like nucleoids ofD. radiodurans to maintain the linear continuityof the genome even when fragmentation hasoccurred.
keeps 4-10 copies of all its genes at any giventime depending onits current stage ofgrowth
the copies appear to be stacked on top of eachother. The additional genomes may allow thebacterium to recover at least one complete copy
ofits genome after exposure to radiation.
There is no evidence of conjugation, andnophage capable ofinfectingD. radiodurans has
beenidentified.
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Transmission electronmicrographs of cryofixedD.radiopugnans (A and C) andD.radiophilus (B and D) cells. (A)
Regular staining. The darklystained particles are ribosomes,while the lightly stained spacecontains chromatin. (B, C, and D)Cells stained with the DNA-specific reagent osmium-ammine-SO2 (27). DNA toroids (indicatedby arrows) are evident in panelsA, B, and C, whereas in panel Dthe toroids are detected edge on.Because thin sections are used,some (cross-sectioned)specimens reveal only onecompartment. Scale bars, 0.5 m.
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A - Emission spectrum ofUV.
B - Absorp
tion of
UVligh
tby biomo
lecu
les(nucleotide bases, DNA, enzymes, others).
C - IntensityofUVlight.
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A team of Russian and American scientists
proposed that the radioresistance ofD.
radiodurans had a Martian origin. Evolution of
the microorganism could have taken place onthe Martian surface until it was delivered to
Earth on a meteorite. However, apart from its
resistance to radiation, Deinococcus is
genetically andbiochemically very similar toother terrestrial life forms, arguing against an
extraterrestrial origin
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D
einococcus radiodurans has fewer DNA repairgenes than the radiation-sensitive bacterium E. coli.D. radiodurans doesn't appear to possess any DNArepairgenes that some otherbacterium doesn't alsohave.
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there are six known mechanisms:
Homologous recombination (HR)
Non-homologous end-joining (NHEJ)
Single strand annealing (SSA) Synthesis dependent strand annealing(SDSA)
Break-induced replication (BIR)
Copy choice (CC)
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Non-homologous end-joining (NHEJ)
ofDNA fragments
Non-homologous endjoining (NHEJ) functions in all
kinds of cells, from bacteria to man
NHEJ ofdouble-strandedbreaks (DSBs)in DNA is
accomplishedby a series of proteins that work togetherto carry out the synapsis. The main proteins involvedin
NHEJ in eukaryotes are DNA ligase IV, XRCC4, the
catalytic subunit of DNA-dependent proteinkinase (DNA-
PKcs),Ku protein
,and possibly Artemis
Three steps have beenidentifiedin the NHEJ process:
DNA end-binding andbridging, terminal end processing,
and ligation.
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(i) DNA End-binding and Bridging
NHEJ is initiatedby the recognition and
binding of the Ku protein to the brokenDNA ends;
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Single strand annealing (SSA)
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Synthesis Ddependent Stran
Annealing (SDSA)
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Break-induced replication (BIR)
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Copy choice (CC)
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nitric oxide plays animportant role in the
bacteria's recovery from radiation
exposure: the gas is required fordivision
and proliferation after DNA damage has
been repaired. A gene was described that
increases nitric oxide production after UV
radiation, andin the absence of this genethe bacteria were still able to repair DNA
damage but wouldnot grow]
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the bacterium uses manganese complexes asantioxidants to protect itself against radiationdamage
combining orthophosphate (Pi) complexes of Mn2+ withcommon metabolites (e.g., uridine and peptides)in the
protection of enzymes from extreme oxidative damagecausedduringirradiation. These complexes areimmensely radioprotective of proteins but not DNA
the presence of Manganese(II) contributes to thecondensation of the D. radiodurans genome,neutralizingthe repulsing effects of the phosphate backbone andenabling the organism to better tolerate radiation
, D. radiodurans use LEA proteins Late EmbryogenesisAbundant proteins expression to protect againstdesiccation.
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Applications
Deino coccus is very resistance to
radiation,it usedinbioremediation to
consume anddigest solvents and heavy
metals , however the other organisms that
make bioremediationis not resistance to
radiation
bioremediationis an application wherebiological agents such as microbes are
used to decontaminate polluted water or
soil sites
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They useddeinococcus to detoxificate the radioactive
wastes that generated from the nuclear weapons
manufacture, these wastes contain cellulose ,the u.vradiationinhibt the activity of cellulose enzyme ,but
whole cell or crude extraction ofdeinococcus usedin
these sites to make protect to cellulose enzyme.
It has the ability ofinformation storage.
In cold wars the radioactive byproducts where dumped
3000 sites around country, 70 million cubed meters of
soil and 3 trillion liter of water are contaminatedby
uranium and and other radioactive wastes.
They used the deinococcus to decrease the cost of
decontaminated these sites,it was decontaminatedby
300 billiondolars but after usingdeinococcus the coast
become very low
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Any questions??
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The EndThe End
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Mohammed Ahmed Ismail
Ahmed Mohammed KhamisAhmed Abd El-Mohsen
MahmoudTarek
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