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8/8/2019 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

Cast

Mohammed Ahmed Ismail

Ahmed Mohammed KhamisAhmed Abd El-Mohsen

MahmoudTarek

Ahmed Abbas

Ahmed Said

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