DNA RNA INFORMATIONS

CANCER GENES - 'METHYL MAGNET'

2011-08-26T00:33:00.000-07:00

Medical researchers have discovered a new type of mechanism causing cancer susceptibility, showing that tiny changes in some anti-cancer genes can act as magnets to attract modifying "biochemical tags", effectively switching them off and predisposing families to an increased risk of the disease.

The study and its findings are reported in the leading international journal Cancer Cell.

The researchers, from the University of New South Wales (UNSW), believe a tiny spelling mistake involving a single letter in the DNA sequence near the start of the genes is what attracts the biochemical tag – known as methylation.
This biochemical tag directly impacts on our DNA, by switching genes off.
"Methylation sits on top of our DNA, and provides the instructions to turn the gene off," explains study co-leader, Dr Megan Hitchins, from UNSW's Lowy Cancer Research Centre.
In one well-known cause of hereditary cancer, changes in the cancer-prevention gene MLH1 are passed from parent to child creating up to 80 percent risk of developing bowel, uterine and other cancers. However, some families with hereditary cancer have no spelling mistakes in MLH1, but instead have methylation sitting on the gene.
"When the methylation attaches to the MLH1 gene in these families, it causes it to be completely switched off and as a consequence cancer develops," says study co-leader and head of the adult cancer program at the Lowy Cancer Research Centre, Professor Robyn Ward. "But until now, we did not understand how these methylation tags were being passed from parent to child."
In the study the researchers looked at three generations of a large family, who had cancer at a young age, but in whom no spelling mistakes typical of this hereditary cancer syndrome had been found. Strikingly several members of the family from all generations had methylation tags on their gene.
"In this family, biochemical tags attached to the MLH1 gene were present in all three generations. This was intriguing since these markers are usually removed during the production of eggs and sperm," Dr Hitchins said.
"What we found was that a subtle change near the gene was acting like a magnet to attract methylation. So it was not the methylation itself that was being passed from parent to child, but rather the DNA change, and this acted as a methyl magnet," she said.
The methylation was cleared away in the sperm and eggs and then recreated in each new generation, the researchers said.
Professor Ward said the discovery pinpointed the cause of cancer in this family and it offered new options for genetic diagnosis, counselling and early interventions in other families at risk of hereditary cancers.
The team is also exploring the use of certain drugs to clear away the methylation in cancer to switch the anti-cancer genes back on again. In the future these drugs may be used to create a more targeted approach to cancer treatment and possibly prevention.

DNA and RNA arrived from space.

2011-05-06T21:55:00.000-07:00

For some reason or another, all of us like to believe that Earth is special - after all, our planet is the only one able to sustain life that we know of. Indeed, Earth is special in its own way, but life would not have been possible without the significant contribution of material coming form space. In fact, a new study shows that the compounds making up DNA and RNA actually originated in space, not on Earth as previously thought, and were brought here by meteorite fragments and other similar objects.

"Because meteorites represent leftover materials from the formation of the solar system, the key components for life - including nucleobases - could be widespread in the cosmos. As more and more of life's raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely," said Mark Sephton, professor of Earth science and engineering at Imperial College London and co-author of the study."We believe early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations," said the leader of the study, Zita Martins of the Department of Earth Science and Engineering at Imperial College London.

In 1969, a meteorite fragment, known today as the Murchison meteorite, crashed in the Australian outback. A thorough analysis, following its discovery, showed that it contained uracil and xanthine molecules (nucleobases), which are building blocks for genetic materials made up of a heavy carbon isotope. On Earth, such molecules contain only light carbon isotopes.

However, these two molecules are just a few of many others found in the respective fragment. "There are about 70 different amino acids in the Murchison meteorite. About six or so are the same kinds of amino acids associated with life on Earth," said David Deamer from the University of California.

The uracil molecule is one of the four bases for the RNA molecule, therefore it is invaluable to life. Deamer points out that, although these molecules have been proven to originate in space, they could have been developed on Earth just as well. Nevertheless, the proportion of molecules originating only in space or only on Earth is currently unknown.

"We don't know the answer yet. Most people would say that both contributed to the organic compounds available on Earth, but we don't know with certainty how much of one compared to the other," said Deamer.

between 3.8 and 4.5 billion years ago, when primitive life first appeared, the Earth and Mars could have been literally bombarded with meteorites similar to the Murchison, thus studying the impact they would have had on different planets could reveal how life evolved in the solar system.

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UBC Scientists extracted dilluted and contaminated dna

2011-05-06T21:50:00.000-07:00

University of British Columbia researchers have developed a new way to extract DNA and RNA from small or heavily contaminated samples that could help forensic investigators and molecular biologists get to “the truth.”
“By exploiting the physical traits of DNA – electric charge, length and flexibility – we’ve been able to extract DNA from samples that would otherwise not produce enough clean DNA for analysis,” says UBC Biophysics Prof. Andre Marziali.
The technique is being commercialized through Boreal Genomics, a UBC spin-off company, and is expected to have broad applications from basic life-science research to forensic sample analysis, bio-defence and pathogen detection for food safety and clinical diagnostics.
The research team, which includes scientists from UBC and BC Cancer Agency’s Genome Science Centre, details the technique in this week’s Proceedings of the National Academy of Science.
Extracting DNA by conventional methods – which rely on the molecules’ chemical properties – has proven challenging when there are only trace amounts of DNA or when the source sample has contaminants with similar chemical traits.
“We’ve found that DNA and RNA respond to electric fields in a way that is very different from other molecules,” says Marziali. “By exploiting this unique property, we were able to extract high quality DNA from a highly contaminated sample from the Athabasca oil sands.”
The team also successfully tested the technique on samples provided by the RCMP.
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Cystic Fibrosis

2011-05-06T03:56:00.000-07:00

Cystic Fibrosis (CF) is one of the most common genetic diseases in the United States. It is caused by a change in a gene called CFTR. A December 2009 report by "Anesthesia & Analgesia" summarizing the genetic basis of CF noted that there are more than 1,000 possible changes in the CFTR gene that can cause CF, and that approximately one of every 29 Caucasian Americans have a mistake in one copy of their CFTR gene. These people do not have CF since they still have one good copy of the CFTR gene. However, when both parents have one damaged CFTR gene, they have a 25-percent chance that any child of theirs will inherit one bad copy of CFTR from each parent and have cystic fibrosis. As of 2010, there is no cure for CF, but a number of therapies have been developed that can treat the symptoms associated with cystic fibrosis.

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DNA REPLICATION

2011-04-18T18:25:00.000-07:00

Hello Friends, Today we have a look on "DNA REPLICATION". What does it means.

At first we gone look on Biochemical reaction for Dna Replication.

DNA archetype begins with the "unzipping" of the ancestor atom as the hydrogen bonds amid the abject pairs are broken. Once exposed, the arrangement of bases on anniversary of the afar strands serves as a arrangement to adviser the admittance of a commutual set of bases on the fiber actuality synthesized.The new strands are accumulated from deoxynucleoside triphosphates.Anniversary admission nucleotide is covalently affiliated to the "free" 3' carbon atom on the pentose (figure) as the additional and third phosphates are removed calm as a atom of pyrophosphate (PPi). The nucleotides are accumulated in the adjustment that complements the adjustment of bases on the fiber confined as the template.

Thus anniversary C on the arrangement guides the admittance of a G on the new strand, anniversary G a C, and so on.When the action is complete, two DNA molecules accept been formed identical to anniversary added and to the ancestor molecule.

Role of Enzymes......

A allocation of the bifold braid is unwound by a helicase. A atom of a DNA polymerase binds to one fiber of the DNA and begins affective forth it in the 3' to 5' direction, application it as a arrangement for accumulating a arch fiber of nucleotides and reforming a bifold helix. In eukaryotes, this atom is alleged DNA polymerase basin (δ). Because DNA amalgam can alone action 5' to 3', a atom of a additional blazon of DNA polymerase (epsilon, ε, in eukaryotes) binds to the added arrangement fiber as the bifold braid opens. This atom charge amalgamate alternate segments of polynucleotides (called Okazaki fragments). Another enzyme, DNA ligase I again stitches these calm into the backward strand.

Dna Replication is semi conservative.

When the archetype action is complete, two DNA molecules — identical to anniversary added and identical to the aboriginal — accept been produced. Anniversary fiber of the aboriginal atom has remained complete as it served as the arrangement for the amalgam of a commutual strand. This approach of archetype is declared as semi-conservative: one-half of anniversary new atom of DNA is old; one-half new. Watson and Crick had appropriate that this was the way the DNA would about-face out to be replicated. Proof of the archetypal came from the abstracts of Meselson and Stahl
Follow this link to see the proof...http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Meselson_Stahl.html

Another important point is the SPEED OF REPLICATION.

Among Bacteria

The distinct atom of DNA that is the E. coli genome contains 4.7 x 106 nucleotide pairs. DNA archetype begins at a single, anchored area in this molecule, the archetype origin, gain at about 1000 nucleotides per second, and appropriately is done in no added than 40 minutes. And acknowledgment to the attention of the action (which includes a "proof-reading" function), the job is done with alone about one incorrect nucleotide for every 109 nucleotides inserted. In added words, added generally than not, the E. coli genome (4.7 x 106) is affected after error!

Among Eukaryotes

The boilerplate animal chromosome contains 150 x 106 nucleotide pairs which are affected at about 50 abject pairs per second. The action would booty a ages (rather than the hour it absolutely does) but for the actuality that there are abounding places on the eukaryotic chromosome area archetype can begin. Archetype begins at some archetype origins beforehand in S appearance than at others, but the action is completed for all by the end of S phase. As archetype nears completion, "bubbles" of anew replicated DNA accommodated and fuse, assuredly basic two new molecules.

We now Look on Control of Replication....

With their assorted origins, how does the eukaryotic corpuscle apperceive which origins accept been already replicated and which still anticipate replication?

An observation: When a corpuscle in G2 of the corpuscle aeon is alloyed with a corpuscle in S phase, the DNA of the G2 basis does not activate replicating afresh alike admitting archetype is proceeding commonly in the S-phase nucleus. Not until mitosis is completed, can freshly-synthesized DNA be replicated again.

Two ascendancy mechanisms accept been articular — one absolute and one negative. This back-up apparently reflects the acute accent of absolute archetype to the candor of the genome.

It has two kind of controls a positive and a negative.

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DNA HELPS TO FIND CRIMINALS

2011-04-11T22:43:00.000-07:00

DNA is also used to find the criminals of rapist and murderers.It was the "fingerprint of the 21st century".The use of DNA evidence has not kept pace with its potential. From many years, DNA evidences from hundreds of thousands of rape and murder cases that was collected by police but never sent to labs for analysis. As this evidence backlog, one of the biggest problem to getting rapists out of the streets, became overwhelming for states and other local peoples, RAINN concluded that a federal solution should be implemented. To help to launch the effort. Also RAINN led a successful national campaign to educate the media and lawmaker peoples about the backlog of unanalyzed DNA casework and bring this enormous problem to public attention. RAINN's president and founder, Scott Berkowitz, also testified before the U.S. Congress regarding DNA testing backlog.

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INFORMATION ON DNA

2011-04-11T22:38:00.001-07:00

Deoxyribonucleic acid (DNA)   is a nucleic acid present in the cells of all living organisms. It is   often referred to as the “building blocks of life,” since "DNA"  encodes the genetic material which determines what an organism will  develop into. In addition to maintaining the genetic blueprints for its  parent organism, DNA also performs a number of other functions which are critical to life.
This   nucleic acid was first identified in 1889, when researcher Friedrich   Miescher found a substance he called “nuclein” in human cells. In the   early 20th century, several researchers including Phoebus Levene and   William Astbury performed additional research on nuclein, beginning to   understand its components, structure, and role in life. A seminal   article published in Nature in 1953 by James Watson and Franklin Crick is often cited as the breakthrough moment in DNA research, as it correctly posited the distinct structure of DNA, with significant help from scientist Rosalind Franklin.


  
DNA stands      for deoxyribonucleic acid.
DNA is      allotment of our analogue of a active organism.
DNA is begin      in all active things.
DNA was aboriginal      abandoned in 1869 by Friedrich Miescher.
James Watson      and Francis Crick ample out the anatomy of DNA.
DNA is a      bifold helix.
The anatomy      of DNA can be likened to a askance ladder.
The rungs of      the ladder are fabricated up of “bases”
Adenine (A)      is a base.
Thymine (T)      is a base.
Cytosine (C)      is a base
Guanine (G)      is a base.
A      consistently pairs with T in DNA.
C      additionally pairs with G in DNA.
The bulk of      A is according to the amoun tof T, aforementioned for C and G.
A+C = T+G
Hydrogen      bonds authority the bases together.
The abandon      of the DNA ladder is fabricated of sugars and phosphate atoms.
Bases      absorbed to a sugar; this circuitous is alleged a nucleoside.
Sugar +      phosphate + abject = nucleotide.
The DNA      ladder usually twists to the right.
There are      abounding conformations of DNA: A-DNA, B-DNA, and Z-DNA are the alone ones      begin in nature.
About all      the beef in our anatomy accept DNA with the barring of red claret cells.
DNA is the      “blueprint” of life.
Chromosomal      or nuclear DNA is DNA begin in the basis of cells.
Bodies      accept 46 chromosomes.
Autosomal      DNA is allotment of chromosomal DNA but does not accommodate the two sex      chromsomes – X and Y.
One      chromosome can accept as little as 50 actor abject pairs or as abundant as      250 actor abject pairs.
Mitochondrial DNA (mtDNA) is begin in the mitochondria.
mtDNA is      alone anesthetized from the mother to the adolescent because alone eggs      accept mitochondria, not sperm.
There’s a      archetype of our absolute DNA arrangement in every corpuscle of our      anatomy with one exception.
Our absolute      DNA arrangement is alleged a genome.
There’s an      estimated 3 billion DNA bases in our genome.
One  actor      bases (called a megabase and abbreviated Mb) of DNA  arrangement abstracts      is about agnate to 1 megabyte of computer  abstracts accumulator space.
Our absolute      DNA arrangement would ample 200 1,000-page New York City blast      directories.
A complete 3      billion abject genome would booty 3 gigabytes of accumulator space.
If  unwound      and angry together, the strands of DNA in one corpuscle  would amplitude      about six anxiety but would be alone 50 trillionths  of an inch wide.
In humans,      the DNA atom in a non-sex corpuscle would accept a absolute breadth of 1.7      metres.
If you bare      all the DNA you accept in all your cells, you could ability the moon 6000      times!
Our sex      cells–eggs and sperm–have alone bisected of our absolute DNA.
Over 99% of      our DNA arrangement is the aforementioned as added humans’.
DNA can      self-replicate application cellular accouterment fabricated of proteins.
Genes are      fabricated of DNA.
Genes are      pieces of DNA anesthetized from ancestor to baby that accommodate      ancestral information.
The      boilerplate gene is 10,000 to 15,000 bases long.
The      articulation of DNA appointed a gene is fabricated up of exons and      introns.
Exons accept      the cipher for authoritative proteins.
Introns are      amid sequences sometimes alleged “junk DNA.”
Junk DNA’s      action or abridgement thereof is a antecedent of debate.
Allotment of      “junk DNA” advice to adapt the genomic activity.
There are an      estimated 20,000 to 25,000 genes in our genome.
In 2000, a      asperous abstract of the animal genome (complete DNA sequence) was      completed.
In 2003, the      final abstract of the animal genome was completed.
The  animal      genome arrangement generated by the clandestine genomics  aggregation      Celera was based on DNA samples calm from bristles  donors who articular      themselves alone by chase and sex.
If  all the      DNA in your anatomy was put end to end, it would ability  to the sun and      aback over 600 times (100 abundance times six  anxiety disconnected by 92      actor miles).
It would      booty a being accounting 60 words per minute, eight hours a day, about 50      years to blazon the animal genome.
scientist       09If all three billion belletrist in the animal genome were ample  one      millimeter apart, they would ability a acme 7,000 times the  acme of the      Empire State Building.
DNA is      translated via cellular mechanisms into proteins.
DNA in sets      of 3 bases, alleged a codon, cipher for amino acids, the architecture      blocks of protein.
Changes in      the DNA arrangement are alleged mutations.
Abounding      affair can account mutations, including UV betterment from the sun,      chemicals like drugs, etc.
Mutations      can be changes in aloof one DNA base.
Mutations      can absorb added than one DNA base.
Mutations      can absorb absolute segments of chromosomes.
Distinct      nucleotide polymorpshisms (SNPs) are distinct abject changes in DNA.
Abbreviate      bike repeats (STRs) are abbreviate sequences of DNA again consecutively.
Some      genitalia of the DNA arrangement do not accomplish proteins.
Genes      accomplish up alone about 2-3% of our genome.
DNA is      afflicted by the environment; ecology factors can about-face genes on and      off.
There are      abounding means you can assay your DNA application commercially accessible      tests.
Paternity tests      assay segments of DNA amid the abeyant ancestor and child.
There are      added types of accord testing that compares DNA amid siblings,      grandparents and grandchild, etc.
DNA tests      can advice you accept your accident of disease.
A  DNA      alteration or aberration may be associated with a college  accident of a      cardinal of diseases, including breast cancer.
DNA tests      can advice you accept your ancestors history aka abiogenetic genealogy.
DNA tests      can advice you accept your indigenous make-up.
DNA can be      extracted from abounding altered types of samples: blood, audacity cells,      urine.
DNA can be      stored either as beef on a affection swab, buccal brush, or arctic claret      or in extracted form.
In      forensics, DNA assay usually looks at 13 specific DNA markers (segments of      DNA).
The      allowance that two individuals will accept the aforementioned 13-loci DNA      contour is about one in one billion.
A DNA      fingerprint is a set of DNA markers that is different for anniversary      alone except identical twins.
Identical      twins allotment 100% of their genes.
Ancestors      allotment 50% of their genes.
A ancestor      and adolescent allotment 50% of their genes.
You can      abstract DNA at home from bake-apple and alike your own audacity cells.
DNA is      acclimated to actuate the full-blooded for livestock or pets.
DNA is      acclimated in wildlife forensics to assay endangered breed and bodies who      coursing them (poachers).
DNA is      acclimated in assay victims of accidents or crime.
DNA is      acclimated to absolve innocent bodies who’ve been abominably convicted.
Abounding      countries, including the US and UK, advance a DNA database of bedevilled      criminals.
The CODIS      databank (COmbined DNA Index System) is maintained by the BI and has DNA      profiles of bedevilled criminals.
Polymerase       alternation acknowledgment (PCR) is acclimated to amplify a sample  of DNA      so that there are added copies to analyze.
We eat DNA      every day.
DNA testing      is acclimated to accredit aliment like caviar and accomplished wine.
DNA is      acclimated to actuate the abstention of crops.
Genetically      adapted crops accept DNA from addition animal amid to accord the crops      backdrop like annoyance resistance.
Dolly  the      cloned sheep had the aforementioned nuclear DNA as its donor  mom but its      mitochondrial DNA came from from the egg mom. (Does  that accomplish any      sense?)
Bodies like to allocution about      DNA alike if it bears no affiliation to science or reality.
A       accumulation of bloggers who address consistently about DNA and  analysis      accept affiliated to gether to anatomy The DNA Network.
Lists about      DNA can get a little boring.
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GENOMIC CODE CRACKING - ATOMIC LEVEL GENE DECODING RESULTS

2011-04-07T19:40:00.000-07:00

Hi... Today we seen some information regarding genomic code cracking that is atomic level gene decoding results that is revealed.Freinds Dr. Paul F. Agris, professor of biochemistry at NC State, and academic colleagues from England and Poland show clear evidence for 1966 “Wobble Hypothesis” offered by Francis Crick who was the co-founder of the DNA molecule and its double-helix structure, and Dr. Agris’ own “Modified Wobble Hypothesis” posed in 1991.

The scientists used x-ray crystallography of the cell’s protein-manufacturing unit, the ribosome, to provide a visual snapshot of the decoding process.

This research is published in the December 2004 edition of Nature Structural and Molecular Biology.

The Wobble Hypothesis was Crick’s attempt to make sense of how the cell decodes the genetic information of DNA – the molecule that constitutes all the genetic information in a cell – and then, from that information the biologically active proteins comes to an existence, Dr. Agris results.

The term DNA has 61 three-letter codes that are translated by transfer RNA (tRNA) into amino acids; also proteins are made of amino acids. But the facts is that there are only 20 natural amino acids. Squaring the disparity between the number of codes and the number of amino acids – there are three times as many codes as there are amino acids – became a hurdle for Crick and other early geneticists, Dr. Agris explanation.

Also Crick attempted to clear this hurdle with the Wobble Hypothesis. He based this theory on the first report of a tRNA molecule’s chemical structure discovered by Robert Holley in 1963. Normally, RNA molecules are composed of four nucleosides: adenosine, guanosine, cytosine and uridine (A,G,C,U). But the tRNA molecule which Holley studied included a modified nucleoside called inosine (I), Dr. Agris says. By seeing this inosine in an important area of the tRNA molecule – an area that read the three-letter DNA codes when the cell synthesizes proteins – led Crick to believe that a single tRNA used inosine to read more than one code, and that therefore the 61 codes were decoded by fewer than 61 tRNAs.

Example, Dr. Agris used the amino acid alanine, which has four codes. Crick’s hypothesis would allow that only the two tRNA molecules could be capable to decode all four alanine codes.By using the modified nucleoside I in place of A, G, C or U, one tRNA may be able to read three codes, effectively “wobbling” the reading.

Twenty-five years after the Wobble Hypothesis, Dr. Agris proposed his Modified Wobble Hypothesis. It stated that modified nucleosides other than inosine would in some cases expand tRNAs ability to translate codes by wobbling to greater numbers of three-letter codes, whereas other modified nucleosides would restrict the wobble to only one or two codes.

According to the recent paper,Dr. Agris and colleagues already proved that Agris’ alteration to Crick’s hypothesis was correct: Cellular modification of tRNA alters chemistry and also structure in a manner critical for tRNA to decode more than one three-letter code.

And by using atomic-level resolution – in which researchers can distinguish atom from atom – and working with a tRNA specific for the amino acid lysine,Dr. Agris and his colleagues show modified nucleosides enabling tRNA to decode genomic information on the ribosome, the cell’s protein synthesis machinery.

Thus Specifically, it shows modifications enabling the decoding of two codes. One modification acts like a platform on which decoding takes place, and the other allows a novel chemical and physical interaction to occur between tRNA and the code,Dr. Agris said.

“This is the first visualization that modifications are critical for decoding the genome through wobble,” Said by Dr. Agris.

Dr. Agris says that 15 to 20 percent of tRNAs in all organisms require modified chemistries in order for codes to be properly read and protein synthesis to be successful.

“An understanding of how modified nucleosides enable and improve wobble recognition of the three-letter codes for protein synthesis opens the possibility of using modified nucleosides to expand the cells’ use of tRNA to make new proteins, or in new ways to target the protein synthesis machinery in pathogens,” Said by Dr. Agris.

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Messenger RNA Synthesis

2011-04-06T21:32:00.000-07:00

During transcription, RNA polymerase makes a copy of a gene from the DNA to mRNA as needed. This process is similar in eukaryotes and prokaryotes. One notable difference, however, is that prokaryotic RNA polymerase associates with mRNA processing enzymes during transcription so that processing can proceed quickly after the start of transcription. The short-lived, unprocessed or partially processed, product is termed pre-mRNA; once completely processed, it is termed mature mRNA.
Messenger ribonucleic acid, commonly called messenger RNA or mRNA, is an RNA molecule that encodes a chemical "blueprint" for the synthesis of a protein. Messenger RNA contains a copy of the genetic data contained on a strand of DNA. Ribosomal ribonucleic acid (ribosomal RNA or rRNA) helps to form the ribosome itself.
Same like messenger RNA (mRNA), ribosomal RNA does not transmit genetic information. Instead of this it combines with proteins to create a structure that systematically transforms mRNA into proteins.

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WHAT IS RIBOSOMAL RNA (RRNA) ????

2011-03-29T21:31:00.000-07:00

There are 4 kinds. In eukaryotes, these are

18S rRNA. One of these molecules, forth with some 30 altered protein molecules, is acclimated to accomplish the baby subunit of the ribosome.
28S, 5.8S, and 5S rRNA. One anniversary of these molecules, forth with some 45 altered proteins, are acclimated to accomplish the ample subunit of the ribosome.

The S cardinal accustomed anniversary blazon of rRNA reflects the amount at which the molecules debris in the ultracentrifuge. The beyond the number, the beyond the atom (but not proportionally).

The 28S, 18S, and 5.8S molecules are produced by the processing of a distinct primary archetype from a array of identical copies of a distinct gene. The 5S molecules are produced from a altered array of identical genes.

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WHAT IS MRNA (MESSENGER RNA) ????

2011-03-29T21:24:00.000-07:00

A atom of RNA that serves as a arrangement for protein synthesis. mRNA is transcribed from a gene and again translated by ribosomes in adjustment to accomplish a protein. Each set of three bases, alleged codons, specifies a assertive protein in the arrangement of amino acids that comprise the protein. The arrangement of a fiber of mRNA is based on the arrangement of a commutual fiber of DNA.

Messenger RNA comes in a advanced ambit of sizes absorption the admeasurement of the polypeptide it encodes. Best beef aftermath baby amounts of bags of altered mRNA molecules, anniversary to be translated into a peptide bare by the cell.

Many mRNAs are accepted to best cells, encoding "housekeeping" proteins bare by all beef (e.g. the enzymes of glycolysis). Other mRNAs are specific for alone assertive types of cells. These encode proteins bare for the action of that accurate corpuscle (e.g., the mRNA for claret in the precursors of red claret cells).

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DNA GENE DECODING SITES

2011-03-28T11:03:00.000-07:00

The additional blazon of account now on the web that will appulse adoptions is the adeptness to break your child's DNA. Adoptive families will acquisition this armpit advantageous for abounding reasons. Your child's DNA is decoded, accouterment you with abundant admired information. The acquaintance is accompanying unsettling, anecdotic and empowering.

While these adaptation sites accommodate the befalling for DNA Acceptance Networking, that seems to be a by-product of their capital function, which is to break your DNA. For the acceptance world, casework like this accept amazing implications, including:

(i) In the majority of adoptions in the world, there is little or no advice about the bearing father. This includes calm adoptions, as able-bodied as adoptions from added genitalia of the world. Adaptation your child's DNA will accommodate you with cogent advice about the bearing ancestor and the bearing mother. The websites affirmation they acquiesce you to attending 20 or 40 years into the approaching at cogent DNA markers that will affect your child's bloom (such as pre-disposition to assertive diseases).
(ii) Once registered with some sites, you will be automatically brash over the abutting 10, 20 or 30 years, as medical science makes new discoveries and advances.
(iii) In some situations DNA adaptation may become accessible as allotment of pre-adoption medical and amusing advice about the child. Currently, parents accept bound medical information, photographs, and sometimes a video. Perhaps in the approaching a DNA besom will become allotment of this pre-adoption advice package.
(iv) As countries become added careful about whom may accept their accouchement (such as China) will they demand DNA tests of the adopting parents? Adopting Parents already accept to accumulation medical and lab letters as allotment of a abstracts for all-embracing adoption. Are DNA letters next?

These websites will accompany abundant opportunities, but additionally abundant quandaries. We will no best accept the botheration of not knowing, but instead accept the accountability of whether we demand to apperceive in the aboriginal place. We will apperceive whether our accouchement are agreeable to assertive ancestry or talents, athletics, music or languages, and we'll animate them to accompany assertive paths. I accept afresh declared these websites to clients, accompany and relatives. It is absorbing how abounding bodies accept said, "But do you absolutely demand to apperceive this information?". Clearly, some bodies would rather not apperceive and aloof let the approaching unfold.

1.... www.23andme.com

This is a web-based account that helps you accept your DNA. Send in a sample of your child's saliva and see how the decoded genes announce your child's future. This armpit is partly adjourned by Google. The amount for a DNA assay is $999, and you will accept a address allegory about 600,000 DNA checkpoints.

At this time their account is alone accessible in the USA, Europe and Canada, although it will aggrandize in the approaching to added countries. In acknowledgment to my catechism to this armpit as to whether adopting parents could use it to accept the DNA decoded for a adolescent proposed to them for adoption, the acknowledgment was "Our account is not advised to be acclimated for abiogenetic screening purposes."

Doug Chalke
Executive Director
Sunrise Family Services Society
Vancouver, February, 2008
www.SunriseAdoption.com

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WHO CAN USE DNA ADOPTION

2011-03-28T10:59:00.000-07:00

A ample spectrum of the acceptance association will be able to accomplish use of these sites:

(i) Biological parents who placed a adolescent for acceptance (or conceivably alone a child) can attending for their adolescent common with one registration.
(ii) Aback adopted accouchement become teenagers or adolescent adults, they generally demand to acquisition out added about their roots. While they may not acquisition their bearing parents immediately, they may locate added relatives. In adjustment to analyze siblings, half-siblings, cousins or grandparents, it will be all-important for one of their biological parents to annals on the armpit (At this time you charge a ancestor to additionally annals in adjustment to say definitively that two ancestors are siblings). Those ancestors may about-face up anon or a decade or two afterwards as new ancestors annals on the site.
(iii) Adopted Adults. Life is long, and at some point aback adopted accouchement accept become adults, they frequently demand to attending for their roots. While adoptive parents today usually explain to their accouchement that they were adopted, that has not consistently been the case, nor is it universally true. As a result, individuals registering on these sites, who had no abstraction that they were adopted, may be in for a surprise.
(iv) Adoptive parents who demand to acquisition siblings, bearing parents, or added ancestors of their adopted adolescent can annals their child. Parents registering accouchement over 13 crave the child's acceding to do this. In fact, it appears that analytical adopted teenagers could acceptable annals themselves if they accept admission to $149.
(v) Acceptance Agencies may demand to accommodate advice about DNA Acceptance Networking in their acceptance apprenticeship programs. It's a absoluteness analysis for parents who accompaniment they demand to adopt, but never demand annihilation to do with the bearing ancestors and that's why they demand to accept overseas. At some point their adolescent may annals and acquisition ancestors in added countries.

Not anybody complex in acceptance will demand to participate in this common agreement in affiliated research. While best adopted accouchement demand to apperceive who their biological parents are, this is not consistently true. However, for those who do demand to apperceive area their adolescent is, or who their biological ancestor is, these websites are already bearing after-effects and matches. An ABC News video clip, which is accessed by a articulation on the GeneTree.com home page, includes an account with an adopted developed who alone knew his bearing date and place, and afterwards begin ancestors in several genitalia of the world.

Since DNA Acceptance Networking will about accommodate a common acceptance alliance registry, bodies should anticipate anxiously afore registering. While anyone can use one of these sites, appropriate precautions charge to be taken aback they are acclimated by the acceptance community. Some individuals may ambition to access counselling afore registering. Acceptance Alliance Registries are amid in best jurisdictions in North America and they frequently accommodate counselling to the parties both afore and afterwards a reunion.

What makes these sites so altered from the sites declared abutting is that no abiogenetic advice is accustomed aback to you (the participant).

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DNA ADOPTION NETWORKING SITES

2011-03-28T10:57:00.000-07:00

With advances in computer technology and DNA science, it seemed acceptable that a way would be begin for the extensive accouchement of China to acquisition their bearing families. That day seemed far off in the future. However that day is actuality now, and it has accustomed 20 years afore I accepted it. A new affectionate of internet website provides the agency for adopting parents of accouchement adopted from China to ascertain if their adolescent has a sibling, half-sibling, accessory or added about adopted anywhere in the world. In addition, bearing parents in China will be able to look for their biological adolescent who has been adopted by a ancestors active about in the world. While China adoptions are the better archetype of what is now possible, it applies to every acceptance in the apple today. I don't anticipate it is an adornment to say that this is the best amazing development in the acreage of acceptance advice in the accomplished 25 years.

There are two new kinds of sites in accurate that assume advantageous to the acceptance community. They are absorbing because both kinds are the aboriginal of a new brand of websites. The aboriginal are DNA amusing networking sites; the additional are primarily gene-decoding sites.

DNA Adoption Networking is a allotment of a new internet account the New York Times has alleged Zygotic Amusing Networking. These networking casework admittance users to body a amusing arrangement about aggregate abiogenetic material. Similar to Facebook, users are able to column photos, amend their profiles, blog, and accelerate letters to anniversary other. Added importantly, for adoptive families they facilitate searches for ancestors and acquiesce associates to analyze abiogenetic makeup.

Basically, you assurance up with the service, do a audacity swab, accelerate it in, and a allocation of your abiogenetic architecture gets compared to others on the databank. You or addition abroad (somewhere in the world) can again bang on a map that shows a brand for every added affiliate about the apple who shares abiogenetic markers begin in your DNA profile.

Perhaps alike added amazing is that the creators of these sites accept that we are alone at the alpha of their abilities and usefulness. Experts accept that every new analysis in the acreage of analysis will accommodate the users with new advice about their identities.

A. DNA ADOPTION NETWORKING SITES
1. www.GeneTree.com

This service:

operates world-wide;
is accessible to accept and accessible to use;
is chargeless (except for the DNA besom accumulating kit $99 - $149);
matches ancestors (such as cousins), which abundantly increases the affairs of award out added advice about the child's ancestors of origin.

The armpit is allotment of a common affiliated and abiogenetic analysis project. Anyone who joins is a actor in this project. (Unfortunately, this advice is not fabricated bright on the website until a apprentice orders a DNA besom kit and is presented with a 6-page arrangement to sign.) Parents who don't like the accommodation of actuality allotment of a analysis activity may demand to canyon on registering. Others will be blessed to be allotment of a DNA analysis activity that additionally provides the befalling for chargeless DNA Acceptance Networking. This armpit is headquartered in Salt Lake City, Utah, which is already accepted as the better centermost of affiliated analysis in the world. Clearly, they demand to accomplish it bigger.

When you adjustment your DNA besom kit ($149) you will be asked to assurance a 6-page contract. Read it carefully. It has some absorbing terms, including:

you are a actor in a analysis study;
no abiogenetic advice is provided aback to you;
you can abjure from the abstraction at any time and accept your advice deleted;
while this armpit will bout two autonomous users of the armpit calm if they want, the armpit will not get complex in accouterment acceptance or ancestors advice (that it may apprentice of) to anyone.

The website has a "Facebook" aspect to it, except you are networking with bodies you allotment agnate DNA with about the apple instead of your called friends. Participants set their own akin of aloofness on this site. In added words, you can annals your DNA and again set aloofness ambit as to the acknowledgment of advice and whether you demand acquaintance with added associates of your continued family. Of course, in accession to aloofness concerns, the abstraction of adoptive families about the apple registering their DNA on a adept database absolutely has a "Big Brother" feel to it. As a result, this account may not address to everyone.
2. www.dnaancestry.com

This armpit is allotment of www.ancestry.com and allows you to use DNA to look for ancestors, clans and by surname groups. www.ancestry.com is an accustomed affiliated analysis armpit additionally headquartered in Utah. It already has a user abject of 15 million, of which 3 actor accept acquaint their searchable ancestors trees. It is the internet's better family-history archive. The analysis kit costs $149 to $179, depending on how adult you demand the after-effects to be.
3. www.familytreedna.com

This website claims to accept the better DNA databases in the acreage of Abiogenetic Genealogy (178,000 records). Their website includes tutorials on the use of your DNA. It additionally has a DNA user's appointment which has posts from adoptees who accept had capricious degrees of success at award relatives. The tests amount $149 to $199.
4. www.a-chinadnaproject.org

Although this armpit is not yet operational as a registry, it does accept absorbing things to say. It is a armpit account account and cerebration about the credibility aloft there. In accession to looking for relatives, a second, appropriately important mission of the website, is to actualize a voluntary, bearding DNA database that will accommodate advice that could account all Asians of Chinese descent. The China Adoptions DNA activity states abundant times on this website that it is not yet underway back it has no funding. It worries about the costs to parents and the amount of accouterment the service. Some adopting parents will demand to delay and see if this adoption-oriented website becomes operational because of the added safeguards that accept been created for the acceptance community.
5. www.tracegenetics.com

This armpit has an all-encompassing FAQ breadth that will advise the clairvoyant a lot about this breadth of science in barefaced language.
It offers testing for both the child's affectionate and benevolent lineage. It again issues a address based on the allotment of ancestor from anniversary of the world's biogeographical areas.
This armpit claims to accept the better Native American DNA database in the world.
This website will additionally accommodate you with custom DNA projects. You can clothier your genomic requests to what you want.

GUIDE TO DNA TESTING LABS

If you’re planning to do a DNA test, hundreds of DNA testing labs are acquisitive to booty your money. Some of them are account every penny they allegation for their services. But abounding added are not.

In my acceptance attending adventure I acclimated several types of DNA testing labs. So I abstruse a lot during that time. And I’ve acquired alike added ability back I absitively to actualize this web site.

Except for some anterior and absolute topics, I accept organized the antithesis of this folio by DNA assay type. If you’re not absorbed in some types, aloof annal bottomward until you acquisition the blazon you need.

Sample Collection Methods

Today, best DNA testing labs use DNA samples from your mouth. Methods accommodate DNA swabs to aggregate beef from central your cheek, and discharge tubes or mouthwash to aggregate saliva. Claret testing is no best necessary.

For abounding tests, you don’t alike accept to appear into a lab. Home DNA tests are broadly used, except as acclaimed below.

Paternity Testing

The parent-child accord is the abutting one possible. As a result, ancestors testing can acquaint you that a man is a child’s ancestor with 99.99% certainty. If DNA testing shows that a man is not the father, you can be 100% assertive of that fact.

Situations involving adolescent custody, adolescent support, bequest and clearing crave acknowledged ancestors tests. In those cases the courts crave all parties to appearance up in being at the DNA testing labs. Then lab cadre will affirm anniversary person’s identity, aggregate the samples, and chase a acknowledged alternation of aegis action through assay and reporting.

Home DNA assay kits for ancestors testing are available. But you should alone use them back the assay is alone for claimed knowledge. Tests done at home are not acknowledged ancestors tests.

For ancestors tests (and the beneath accepted maternology tests) you should accept an AABB-accredited laboratory. AABB is the American Association of Claret Banks. Alike admitting DNA testing labs rarely use claret anymore, this alignment still ensures class quality.

Another acceptance to attending for is ISO 17025. This is the all-around accepted for the abstruse adequacy of arrangement and testing labs.

Recommended Labs for Ancestors Testing

You can attending for a lab that does ancestors tests and meets these standards. Be abiding to analysis out the afterward two labs that I apperceive able-bodied abundant to alone recommend:

f you charge a acknowledged test, again the area of a acceptable testing armpit can be an important factor. If the activated parties are in altered locations, allotment a aggregation like those above, which accept a ample arrangement of sampling sites, can abbreviate biking expenses.

Close Accord Testing

If the parents are not accessible for paternity/maternity testing, you may still be able to actuate whether or not two bodies are related. For example, I knew my ancestor was one of bristles brothers. By comparing my DNA with that of a adolescent from anniversary brother, I was able to actuate which man was my father. To apprentice how I did this see my DNA Sibling Analysis page.

In accession to ancestors and bisected siblings, you can generally administer this blazon of abutting accord testing to grandparents, aunts, uncles, and cousins. But you charge to analysis anxiously with the DNA testing labs that action such tests. And after-effects cannot be as assertive as ancestors testing.

See the Accord Testing folio of this web armpit for two methods and my recommended labs for accepting this done.

Family Tree DNA Testing

If you’re attractive to DNA for ancestor or acceptance attending purposes, I acclaim you use Family Tree DNA. To apprentice why I acclaim this lab, see my FTDNA Review page.

Ethnic or Age-old Ancestor Testing

Testing with Family Tree DNA will additionally acquaint you article about your age-old ancestor by admiration your haplogroup. But if you demand a bigger breakdown, i.e. to abode your ancestors in a specific country, indigenous accumulation or tribe, you will charge added tests.

Some companies specialize in allegory assertive populations, such as Native Americans or African Americans. You can additionally adjustment autosomal testing to admeasurement the aggregate backgrounds of all your ancestors.

To apprentice added about these tests and the DNA testing labs that action them, see my Indigenous DNA Testing page. Be abiding to apprehend all the credibility I accomplish about the limitations of such testing.

No amount what blazon of DNA testing you are considering, attending carefully at anniversary company’s adeptness to accommodate claimed chump service. They charge accept a appear blast cardinal area you can ability absolute bodies to acknowledgment your questions afore and afterwards you adjustment a test.

Most companies acquiesce you to adjustment and pay for a DNA analysis online. But I advance you acquisition a buzz cardinal and analysis it afore you abode the order.

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WHAT IS PROTEIN SYNTHESIS ????

2011-03-28T10:51:00.000-07:00

Hi This is all about protein synthesis.........

Protein amalgam is the action by which alone beef assemble proteins. Both deoxyribonucleic acerbic (DNA) and all types of ribonucleic acerbic (RNA) are complex in this process. Enzymes in the cell's basis activate the action of protein amalgam by unwinding the bare breadth of DNA, so that RNA can be made. The RNA forms as a archetype of one ancillary of the DNA strand, and is beatific to added areas of the corpuscle to aid in the bringing calm of altered amino acids that anatomy proteins. Protein amalgam is so alleged because proteins are "synthesized" through automated and actinic processes in the cell.

Once the fiber of RNA has been fabricated in the nucleus, it is alleged agent RNA (mRNA). The mRNA exits the basis through tiny openings alleged nuclear pores, and moves into the beyond breadth of the cell, accepted as the cytoplasm. Once it exits the nucleus, the mRNA is fatigued against a anatomy accepted as a ribosome, which serves as the cell's assignment base for protein synthesis. At this point, alone one sub-unit of the ribosome is present.

As the mRNA binds to the ribosome sub-unit, it triggers the access of addition fiber of RNA, alleged alteration RNA (tRNA). The tRNA fiber looks for the able abode to bind to the mRNA, and back it finds it, it attaches to the mRNA, while captivation an amino acerbic on one end. Back this occurs, the added sub-unit of the ribosome arrives to anatomy a complete structure. As the ribosome surrounds the strands of RNA, addition fiber of tRNA approaches. This fiber is accustomed addition amino acid, and is altered from the first. Again, the tRNA looks for the able abode to bind to the mRNA.

When the additional fiber of tRNA is in abode with its amino acid, the two amino acids bind calm with advice from the ribosome, as able-bodied as cellular activity in the anatomy of adenosine triphosphate (ATP). This arrangement repeats itself, and the alternation of amino acids grows longer. Back the amino acids accept all been placed in the actual sequence, the alternation folds into a three-dimensional shape. Back this has occurred, the protein is complete.

Once the protein has been auspiciously made, the two sub-units of the ribosome separate, to be abutting afresh for after use. The action of protein amalgam takes abode in abundant ribosomes throughout the cell. A corpuscle which is operating calmly can amalgamate hundreds of proteins every second.

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CANCER DUE TO RADIATION EFFECTS ON DNA

2011-03-28T10:42:00.000-07:00

Cancer is produced if radiation does not annihilate the corpuscle but creates an absurdity in the DNA adapt that contributes to closing accident of ascendancy of corpuscle division, and the corpuscle begins adding uncontrollably. This aftereffect ability not arise for abounding years. Cancers induced by radiation do not alter from cancers due to added causes, so there is no simple way to admeasurement the amount of blight due to radiation. During the aeon advised by the Advisory Committee, abundant accomplishment was adherent to studies of ablaze animals and apparent groups of bodies to advance bigger estimates of the accident of blight due to radiation. This blazon of analysis is complicated by the array of cancers, which alter in radiosensitivity. For example, cartilage bottom is added acute than bark beef to radiation-induced cancer.

Large doses of radiation to ample numbers of bodies are bare in adjustment to account assessable increases in the cardinal of cancers and appropriately actuate the differences in the acuteness of altered organs to radiation. Because the cancers can action anytime in the apparent person's lifetime, these studies can booty seventy years or added to complete. For example, the better and scientifically best admired epidemiologic abstraction of radiation furnishings has been the advancing abstraction of the Japanese diminutive bomb survivors. Added important studies accommodate studies of ample groups apparent to radiation as a aftereffect of their activity (such as uranium miners) or as a aftereffect of medical treatment. These types of studies are discussed in greater detail in the area blue-blooded "How Do Scientists Actuate the Long-Term Risks from Radiation?"

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HOW LONG DOES RADIATION AFFECTS THE DNA????

2011-03-28T10:39:00.000-07:00

HI....TO THIS WE KNOW THAT FOR HOW LONG THE RADIATION HAVE ITS EFFECTS ON DNA.

The aftereffect of the radiation may not be to annihilate the cell, but to adapt its DNA cipher in a way that leaves the corpuscle animate but with an absurdity in the DNA blueprint. The aftereffect of this alteration will depend on the attributes of the absurdity and back it is read. Since this is a accidental process, such furnishings are now alleged stochastic.[100] Two important academic furnishings of radiation are cancer, which after-effects from mutations in nongerm beef (termed actual cells), and ancestral changes, which aftereffect from mutations in antibody beef (eggs and sperm).

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RADIATION EFFECTS ON DNA DUE TO EFFECT OF IONIZING RADIATION AND CADMIUM

2011-03-28T10:32:00.000-07:00

Ionizing radiation, by definition, "ionizes," that is, it pushes an electron out of its apogee about an diminutive nucleus, causing the accumulation of electrical accuse on atoms or molecules. If this electron comes from the DNA itself or from a adjoining atom and anon strikes and disrupts the DNA molecule, the aftereffect is alleged absolute action. This antecedent ionization takes abode actual quickly, in about 0.000000000000001 of a second. However, today it is estimated that about two-thirds of the accident acquired by x application is due to aberrant action. This occurs back the absolved electron does not anon bang the DNA, but instead strikes an accustomed baptize molecule. This ionizes the baptize molecule, eventually bearing what is accepted as a chargeless radical. A chargeless abolitionist reacts actual acerb with added molecules as it seeks to restore a abiding agreement of electrons. A chargeless abolitionist may alluvion about up to 10,000,000,000 times best than the time bare for the antecedent ionization (this is still a actual abbreviate time, about 0.00001 of a second), accretion the adventitious of it abolition the acute DNA molecule. This additionally increases the achievability that added substances could be alien that would abrogate chargeless radicals afore they do damage.

Neutrons act absolutely differently. A fast neutron will bypass orbiting electrons and occasionally blast anon into an diminutive nucleus, animadversion out ample particles such as alpha particles, protons, or beyond bits of the nucleus. The best accepted collisions are with carbon or oxygen nuclei. The particles created will themselves again set about ionizing adjacent electrons. A apathetic neutron will not accept the activity to beating out ample particles back it strikes a nucleus. Instead, the neutron and the basis will animation off anniversary other, like billiard balls. In so doing, the neutron will apathetic down, and the basis will accretion speed. The best accepted blow is with a hydrogen nucleus, a proton that can accelerate or ionize electrons in adjacent atoms.

Effect of cadmium administration (3 mg CdCl2/kg body weight i.p.) and/or whole-body

irradiation (3 Gy of gamma rays) on the rat brain was studied in the course of 21 d after

treatment. The effect was studied on the basis of quantitative analyses of DNA and RNA. It was

found that the changes of nucleic acids in the brain hemispheres were very slight and they lay in

a temporal decrease in DNA content on the 7th – 14th d after the irradiation alone and in

combination with cadmium (CdCl2 administered 30 min before irradiation). In the cerebellum,

the changes of nucleic acids were more profound than in the hemispheres. The decrease in DNA

content in the cerebellum was also only temporal and it occurred on the 1st d after the irradiation

alone. The most interesting finding seems to be the increase in DNA content in the cerebellum in

a later period after the irradiation alone and in combination with cadmium without concomitant

increase in RNA content. This finding suggests increasing number of cells with high

nucleoplasmic ratio (mainly glial elements) in the rat cerebellum in a later period after

irradiation. In general, effect of cadmium administration on the rat brain was less expressed than

effect of irradiation and combination of the two treatments did not induce any summation effect.

Key words: rat, brain, cadmium, gamma radiation, DNA, RNA.

Cadmium is a highly toxic heavy metal with half-life time of about 10 years in

human beings. It accumulates predominantly in the kidneys as well as in liver, which

are the critical target organs (2, 19). Biological role of cadmium in an animal organism

is unknown (9). It is designated as a carcinogen in humans and rodents (20, 23).

However, the concentrations of Cd required to induce overt DNA damage are usually

very high (4, 5, 16). The damage of nucleic acids is due to direct or indirect effects of

cadmium (7). Cadmium induces, for example, an oxidative DNA damage leading to

DNA strand-breaks, DNA-protein cross-linking and inhibition of DNA repair.

128

The effects of ionizing radiation on DNA have been studied in detail for many

years (3, 6, 10, 15, 18, 11, 24). A lot of physical-chemical changes of DNA (e.g.

chemical changes of bases, breaks of phosphodiester bonds in one or both chains of

DNA) were found. Similarly to cadmium, these changes were caused by a direct or

indirect (mediated by reactive free radicals) effects of radiation. In the proliferatively

active tissues, such as haemopoietic and lymphoid tissues and regenerating liver, the

most striking effects of ionizing irradiation include inhibition of DNA synthesis and

mitosis and increase in the number of chromosome abnormalities. Due to the lack of

literature data concerning the influence of cadmium and ionizing radiation on nonproliferating

mammalian tissues, the cytotoxic effects of cadmium and gamma

radiation (alone or in combination) on the rat brain were studied in this model

experiment. The effects were evaluated on the basis of quantitative changes of DNA

and RNA because they can serve as an integral index of damage and recovery of cells

after the insults.

Material and Methods

The experiments were performed on 80 male rats of the SD strain (Anlab

Praha, Czech Republic). The animals were 6 weeks old at the beginning of the

experiments. They were kept under standard vivarium conditions (temperature 22 -

24°C, natural light rhythm), and had access to food and water ad libitum. The animals

were divided into four groups:

- non-treated control rats (C)

- rats treated with cadmium (Cd)

- rats irradiated with gamma rays (Ir)

- rats treated with cadmium 30 min before irradiation (Cd+Ir).

In this experiment, all animals survived. In the previous experiments, by the

use of the same doses of cadmium and ionizing radiation, but realised on younger rats

and in another year season, mortality of 5-10 % of animals was recorded.

Cadmium administration. Cadmium (CdCl2, Lachema Brno, Czech

Republic) was administered i. p. in the dose of 3 mg/kg alone or 30 min before

irradiation (groups Cd and Cd+Ir, respectively).

Irradiation. Animals were whole-body irradiated with the dose of 3 Gy by

gamma rays from a 60Co source (Chisostat Chirana, Czech Republic) at a dose rate of

0.150 Gy.min-1 (groups Ir and Ir+Cd). Doses of cadmium and gamma radiation were

chosen from the wide range of doses on the basis of the results of preliminary

experiments. They appeared to be the highest tolerable doses (as to the survival of rats)

inducing clearly demonstrable biochemical changes in the rat brain.

Determination of RNA and DNA. The animals (6 in each group) were

sacrificed 1, 7, 14 and 21 d after treatment. The brain was immediately excised in toto

and weighed. It was divided into the hemispheres and cerebellum (without truncus

cerebri), because distinct findings were expected due to some differences in structure

and function of these main parts of the brain. RNA and DNA determinations were

carried out according to the method of Tsanev and Markov (22). Tissue samples (in

duplicates) were homogenized in 5% trichloracetic acid solution and then deproteinized

and purified by washing with methanol, chloroform-methanol, benzene and ether. The

separation of RNA and DNA was carried out by consecutive hydrolyses in alkaline

129

(1 M KOH) and acid (0.2 M HClO4) solutions, respectively. The concentration of RNA

and DNA in the hydrolysates was determined by spectrophotometric measurements

(Hitachi, Tokio, Japan) at two wavelengths (RNA at 260 and 286 nm and DNA at 268

and 284 nm).

Statistical analysis. The experimental data were statistically evaluated by

Peritz´ F-test (12) at P≤ 0.05 and P ≤ 0.01 level of significance and they are given as

mean ± S.E.M .

Results

Hemispheres. No significant changes in RNA concentration and total content

were found in the hemispheres of rats exposed to cadmium and/or radiation comparing

to the control rats (Fig. 1). The decrease in DNA concentration in experimental rats

was not statistically significant (Fig. 2). The mean values of total DNA content

decreased after gamma irradiation (Ir) on the 7th d and after combined treatment with

cadmium and gamma irradiation (Cd+Ir) also on the 14th d of the treatment. Changes in

concentration and total content of DNA in experimental rats (Ir and Cd+Ir) were timedependent.

The application of cadmium alone did not cause any significant changes in

DNA in the rat hemispheres. As presented in Table 1, after cadmium administration or

irradiation alone (Cd, Ir) there was a tendency to some increase in the weight of rat

hemispheres. The effect of combined cadmium and radiation treatment (Cd+Ir) on the

weight of hemispheres was rather opposite.

Cerebellum. Cadmium and radiation alone or in the combination (Cd, Ir and

Cd+Ir) induced marked changes in the concentration of RNA in the cerebellum of rats.

As it follows from Fig. 3, statistically significant decrease in RNA concentration in

comparison to control rats was observed after 21 d of treatment. However, decrease in

RNA concentration was not accompanied by adequate decrease in total RNA content in

the organ. The concentration and content of DNA in the cerebellum (Fig. 4)

significantly decreased only 1 d after irradiation (Ir). Later, however, increase in DNA

concentration and especially in DNA content was found in the cerebellum of irradiated

rats of the groups Ir and Cd+Ir. After all treatments (Cd, Ir and Cd+Ir), marked

enhancement of the cerebellum weight was observed mainly in later stages of the

examination

Discussion

The results of the present study indicated that the quantitative changes of RNA

in the brain hemispheres and cerebellum of cadmium treated and/or gamma-irradiated

rats were less expressed than changes of DNA.

In the hemispheres, no quantitative changes of RNA occurred; changes of

DNA manifested themselves in a temporary decrease in total content of DNA in

irradiated rats of the groups Ir and Cd+Ir. We suppose that in both groups, the decrease

in DNA content on the 7th d was caused mainly by irradiation; additional cadmium

administration (Cd+Ir) resulted in extension of the decrease till the 14th d. The DNA

content is considered to be the best biochemical index of cellularity (1), hence, these

results indicate some loss of cells due to apoptosis. Apoptosis of cells is connected with

fragmentation of DNA and following loss of DNA. It seems, therefore, that effects of

irradiation alone and in combination with cadmium imitate process of cell senescence

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WHAT IS RNA ????

2011-03-28T10:30:00.000-07:00

RNA, Ribonucleic Acerbic is an amoebic acid, one of the nucleic acids which back abiogenetic advice in cells.

RNA is primarily fabricated up of four altered bases: adenine, guanine, cytosine, and uracil. The aboriginal three are the aforementioned as those begin in DNA, but uracil replaces thymine as the abject commutual to adenine

RNA is the all-encompassing appellation for polynucleotides, agnate to DNA but absolute ribose in abode of deoxyribose and uracil in abode of thymine. These molecules are complex in the alteration of advice from DNA, programming protein amalgam and advancement ribosome structure. The 4 capital types of RNA are amalgamate nuclear RNA (hRNA), agent RNA (mRNA), alteration RNA (tRNA) and ribosomal RNA (rRNA).

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WHAT IS DNA ?????

2011-03-28T10:23:00.000-07:00

Hi friends today we share some information regarding "what is dna". Deoxyribonucleic acid "DNA" is a nucleic acid that contains the abiogenetic instructions acclimated in the development and activity of all accepted active bacilli and some viruses. The capital role of DNA molecules is the abiding accumulator of information. DNA is generally compared to a set of blueprints or a recipe, or a code, back it contains the instructions bare to assemble added apparatus of cells, such as proteins and RNA molecules. The DNA segments that backpack this genetics advice are alleged genes, but added DNA sequences accept structural purposes, or are complex in acclimation the use of this genetics information.

Chemically, DNA consists of two continued polymers of simple units alleged nucleotides, with backbones fabricated of sugars and phosphate groups abutting by ester bonds. These two strands run in adverse admonition to anniversary added and are accordingly anti-parallel. Attached to anniversary amorous is one of four types of molecules alleged bases. It is the arrangement of these four bases forth the courage that encodes information. This advice is apprehend application the genetics code, which specifies the arrangement of the amino acids aural proteins. The cipher is apprehend by artful stretches of DNA into the accompanying nucleic acerbic RNA, in a action alleged transcription.
DNA Structure

Within cells, DNA is organized into continued structures alleged chromosomes. These chromosomes are bifold afore beef divide, in a action alleged DNA replication. Eukaryotic bacilli (animals, plants, fungi, and protists) abundance best of their DNA central the corpuscle basis and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and archaea) abundance their DNA alone in the cytoplasm. Aural the chromosomes, chromatin proteins such as histones bunched and adapt DNA. These bunched structures adviser the interactions amid DNA and added proteins, allowance ascendancy which genitalia of the DNA are transcribed.

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