RNA Virus

RNA Virus

During the process of DNA replication, errors occasionally occur in the polymerization of the second strand. These errors, called mutations, can have an impact on the phenotype of an organism, especially if they occur within the protein coding sequence of a gene. Error rates are usually very low 1 error in every 10–100 million bases—due to the "proofreading" ability of DNA polymerases.(Without proofreading error rates are a thousand-fold higher; because many viruses rely on DNA and RNA polymerases that lack proofreading ability, they experience higher mutation rates.) Processes that increase the rate of changes in DNA are called mutagenic: mutagenic chemicals promote errors in DNA replication, often by interfering with the structure of base-pairing, while UV radiation induces mutations by causing damage to the DNA structure.Chemical damage to DNA occurs naturally as well, and cells use DNA repair mechanisms to repair mismatches and breaks in DNA—nevertheless, the repair sometimes fails to return the DNA to its original sequence.

In organisms that use chromosomal crossover to exchange DNA and recombine genes, errors in alignment during meiosis can also cause mutations. Errors in crossover are especially likely when similar sequences cause partner chromosomes to adopt a mistaken alignment; this makes some regions in genomes more prone to mutating in this way. These errors create large structural changes in DNA sequence—duplications, inversions or deletions of entire regions, or the accidental exchanging of whole parts between different chromosomes (called translocation).

Treatment for Brain Tumour

Treatment for Brain Tumour



The treatment of human brain tumors rarely. By type and stage of cancer, patients can be treated with surgery, radiation therapy or chemotherapy. Some patients receiving combination therapy.

No version "at any stage of disease, patients may receive treatment to control pain and other symptoms of cancer, reduce the side effects of treatment, and any emotional problems. Thats kind of treatment is called symptom management, supportive care, or palliative treatment.

Doctor is the best person to describe treatment options and discuss the expected results.

Patient may want to talk about the doctors involved in clinical trials, it is a study, to learn a new way of treatment. The Department of "commitment to research Zell" for more information about clinical tryals.

Surgery is the most common treatment for brain tumors. Surgery to open the skull is known as kranyotomi. This is done under general anesthesia. Before the surgery began, the scalp shaved.Then the surgeon makes an pitche open and use a special kind of discovery, removal of a skull bone. Removal of some or all of the tumor, the surgeon James's opening in the skull bone plates or a metal or cloth. Surgeon and then close the incision in the scalp.
Radiotherapy

Radiation therapy (also known as radyotherapi) using high - high-energy rays to kill tumor cells.Radiation can be from X - rays, gamma rays, or protons. A huge machine Ames Radiation Oncology and organizations close to it. When it direkted of radiation in the brain or spinal cord.

Radiation therapy usually follows surgery. Of radiation to kill cancer cells can remain in place. In the past, patients did not have radiation therapy instead of surgery.

Patients in hospital or clinic for radiation therapy. The plan of treatment depends on the type and size of tumor and age of the patient. Each treatment lasted just minutes.

Doctor to make the step to protect surrounding healthy tissue tumors of the brain:

Fraktyonatyon - radyatyon usually to determine the treatment five days a week for several weeks. To provide a total dose of radiation over an extended time by half, to protect healthy tissue tumors in the region.

Hiperfraktyonatyon - Davis radiation small idol of patients two or three times a day, rather than a larger amount of time.

Stereotaktik radiotherapy - a narrow-beam radiation direkted lungs from different angles.Technique, patients wear the top of the strict structure. A wrong card or scan images to create the exact location of the tumor. Doctors use a computer to determine the necessary dose of radiation, as well as south and the angle of radiation beam. During the treatment, we can identify a single visit, or a few visits.

3 - Three-dimensional radiation therapy konformal - a computer creates a 3 - three-dimensional images, lungs and surrounding brain tissue. A type of medical purpose of the exact shape of the beam of radiation oncology. To accurately focus radiation beams defensive in normal brain tissue.

Proton beam radiation therapy - the source of the proton radiation, instead of X - ray. Dr. Ames proton beam cancer. Protons through healthy tissue without compromising it.
Tshemotherapi

Tshemotherapi, using drugs to kill cancer cells, is sometimes used to treat brain tumors. Drugs will decide either orally or through the injection. Either way, the drugs enter the blood circulation and the passage of the body. The drug is usually to return to the moon is as follows for each hour of treatment.

Tshemotherapi may determine the out-patient of the hospital, doctor's office or home. Rareli, patients may need to stay in hospital.

Children more likely than adults to chemotherapy. However, the elderly can have post-operative chemotherapy and radiotherapy.

For some patients with brain cancer, surgeons remove some chip implanted and tumors containing chemotherapy. Each woman is about the size of a dime. In the past few weeks, the chip is dissolved, the release of drugs to the brain. The drug can kill cancer cells.

Transgenic plants

Transgenic plants 

 

Transgenic plants plants created by introducing genes from other species through genetic engineering. These systems are usually developed to produce certain desirable characteristics such as resistance to disease, parasites and resistance to herbicides and resistance to certain environmental conditions. To know the transgenic plants and the risks and benefits, read on.
A transgenic organism is the term used to describe a type of genetically modified organism whose genetic material is manipulated to produce changes in the body with the leg you want. To achieve this objective, the genetic material or DNA of an organism is injected in the nucleus of cells play another agency in the same or different, in order to produce or transport suddenly desirable. This technique of creating transgenic organisms is called recombinant DNA. In other words, transgenic organisms are organisms with a single gene or genes transferred from another organism of the same or different species in the laboratory using the technology of recombinant DNA. This technique can be done in both plants and animals to create transgenic plants and animals.

Transgenic plants Appointment

Transgenic plants are plants that are created by introducing genetic material from a different species, using genetic engineering to produce plants with specific characteristics. The genes of different species can be introduced into a plant in several ways. In general, it is easier to produce transgenic plants compared with transgenic animals. In plants, there is no difference between somatic and germ cells and therefore the genes can be introduced into somatic cells and tissues to produce transgenic plants.

In the past, new plant varieties containing genes from two species generated through hybridization or cross. However, the breeding took place between two closely related species. However, modern biotechnology and genetic engineering, integration of genetic material not only connected but also of exotic species to create transgenic plants and genetically modified. Bt corn, Bt cotton and golden rice are just some of the most common examples of transgenic plants created in this way.

Pros and cons of transgenic plants

Production of transgenic plants and the introduction of foreign genetic material is extremely doubtful. A range of benefits and risks of production of these plants have been identified by scientific studies. One of the main advantages of transgenic plants and crops by the introduction of some parts as you want, resistance to diseases, pests and herbicides. This in turn can increase crop yields to meet rising demand for food. Another advantage is that with the help of genetic engineering, it is possible to produce plants that can tolerate adverse environmental conditions such as drought and cold. Even the floor laden with large quantities of salt can be made with the production of genetically modified crops that can grow in saline soils.

All these advantages will ultimately benefit the agricultural sector. With the growing concern about the environmental impacts of using large-scale insecticides and pesticides is very important to reduce the use of these substances. Transgenic plants resistant to pesticides may play an important role in reducing the use of these chemicals. Plant varieties resistant to herbicides can reduce the negative effects of herbicides and the development of transgenic plants resistant to insects can help reduce the total amount of pesticides used. This, in turn, can improve environmental quality. Besides this, some transgenic plants can produce higher levels of nutrients that can improve the nutritional quality of food.

Despite these advantages, the development of genetically modified or altered are widely criticized, particularly by the fact that these plants have a negative impact on the environment, ecosystem and biodiversity. Many also expressed concern that the genetic material of transgenic plants can be transferred to non-GM plant varieties. Although herbicide-resistant transgenic plants, the same quality, if transferred to weeds can make it very difficult to control weeds. Apart from these, it was found that some genetically modified foods, developed by the animals to cause allergic reactions in some individuals. However, no incidence of these severe allergies have been reported in case of manufacture of food for human consumption.

Another issue raised by critics of GM crops is that these plants can release genes of antibiotic resistance in soil, which can cause soil micro-organisms resistant to antibiotics. Apart from these, laboratory studies have suggested that the introduction of genetically modified crops may affect other organisms. How, for example, Bt corn pollen can affect the larvae of monarch butterflies and moths, if they feed on the leaves of the plant milkweed, covered with pollen from maize Bt, but the supporters of GM and GM crops have refuted the claim this and claims that Bt corn pollen on milkweed leaves can reach a high level of concentration to produce such effects. Learn more about

* The investigation of DNA
* Genetically Modified Foods: Benefits and Risks

Briefly, transgenic plants, risks to human health and ecosystems is a controversial issue. Therefore, further detailed studies and investigations to resolve disputes related to transgenic plants, so that consumers can discover the truth about these plants and genetically modified foods. Apart from these, there are many ethical issues are also associated with transgenesis, which must also be adequately addressed.

What are the symptoms of brain tumor?

 What are the symptoms of brain tumor?
Symptoms of brain tumors depend on tumor size, type and location. Symptoms can cause nerve damage or certain parts of the tumor presses on the brain. May they also lead to brain swelling or fluid in the skull when.

This is the most common symptoms of brain tumors:

Headaches (usually worse in the morning)
Nausea or vomiting

Change, language, vision or hearing
Or on foot balance

Changes in mood, personality or ability to concentrate

Memory Problems

Muscle twitching or seizures (epilepsy or convulsions)

Numbness or tingling in hands and feet
These symptoms are a sure sign of brain tumor. Other conditions can also cause these problems. People experiencing these symptoms occur, it should be noted that the treatment as soon as possible. Only doctors can diagnose and treat the problem.

Origin Of Life In RNA? Study Suggests Genetic Molecules May Have Self-Assembled

Origin Of Life In RNA? Study Suggests Genetic Molecules May Have Self-Assembled

 A pair of RNA-like molecules can spontaneously assemble into gene-length chains, chemists in the United States and Spain report. Billions of years ago, related molecules may have created a rudimentary form of genetic information that eventually led to the evolution of RNA and life itself, the researchers say. Although it's likely to be difficult, if not impossible, to prove whether similar proto-RNAs were present at the dawn of life, the researchers are working to see if the proto-RNAs can indeed faithfully encode information and evolve toward RNA.

Origin of life researchers have long thought that RNA, the molecular cousin of the DNA that encodes our genes, may have played a starring role in the initial evolution of life from a soup of organic molecules. RNA has a simpler structure than DNA and is a more adept chemical catalyst. So it would seem that RNA-based life might arise more readily than DNA-based life.

But there are problems with this so-called RNA World hypothesis. For starters, in water, the four chemical components of RNA—the nucleotides abbreviated A, G, C, and U—don't spontaneously assemble to create sizable molecules. So it remains a mystery how the first long gene-length chains of RNA could have taken shape in Earth's ancient oceans. This and other conundrums have led many to believe that RNA may itself be the product of early molecular evolution, and that proto-RNAs arose first and eventually gave way to RNA. "RNA is so perfect today that it has to be the product of evolution," says Nicholas Hud, a chemist at the Georgia Institute of Technology (Georgia Tech) in Atlanta.

rna lifeChemicals known as TAPAS and CA (left) assemble together forming rosettes (middle) that then stack into genelike chains (right).

Researchers have toyed with the idea of proto-RNA for decades and even come up with potential chemical candidates. One such set of proto-RNAs involves two chemicals called cyanuric acid (CA) and triaminopyrimidine (TAP). TAP comes from a family of compounds known as pyrimidines, as do the RNA bases C and U. CA, meanwhile, is a close pyrimidine relative. Previous research had shown that when CA and TAP were put in an organic solvent, groups of three CAs and three TAPs would spontaneously form ringlike structures called rosettes. These rosettes would then stack atop one another to form long chains.

Unfortunately, in water CA and TAP clump together in large ribbons and sheets and quickly fall out of solution, making it hard to conceive of how these proto-RNAs could have stored genetic information in the earliest stages of life.

Now, however, Hud and his colleagues at Georgia Tech and the Institute for Research in Biomedicine in Barcelona, Spain, have solved this solvent problem. The researchers gave TAP a short chemical tail, transforming it into a chemical they call TAPAS, as they reported on Friday in the Journal of the American Chemical Society. And that one change encourages it to assemble with CA to form rosettes in water. What is more, the rosettes stack atop one another, forming long genelike chains made up of as many as 18,000 individual TAPAS and CA components—quite a stack of small plates.

"The nice thing [about the current study] is this is a demonstration of self-assembly in water," says Ramanarayanan Krishnamurthy, an origin of life chemist at the Scripps Research Institute in San Diego, California. "That is a step in the right direction."

The next step, Hud says, will be to see whether this two-component assembly can be made to encode information like a primitive gene and to evolve toward the structure of RNA. If so, that still won't settle the debate as to whether CA and TAPAS gave life its start. But it will suggest one plausible chemical route to life's origin.

Obesity also a threat in developing countries

Obesity also a threat in developing countries

Sadly, we are getting accustomed to see emaciated people in poor countries and extremely fat people in rich countries. However, as countries develop this is getting far form reality as both starvation and obesity are closely linked with poverty, and as such they are both symptoms of malnutrition.
The negative effects of unhealthy processed fat and sugar-rich diets in combination with low physical activity began to be recognized in the early 1990s, but they did not become clearly acknowledged until diabetes, hypertension, and obesity began to dominate the world.

As well as in countries with high income levels, rates of obesity and overweight are widely documented in the poorest countries of sub-Saharan Africa and South Asia. In these countries, higher incomes imply access to unhealthy fattening food, and consequently, higher prevalences of obesity. Healthy food is usually either not available or not affordable. While in the developed world, obesity is already considered a pandemic, this is also now true for the developing countries. Obesity is affecting both rich and poor countries and causing more deaths than undernourishment, according to the World Economic Forum, which is actually bankrupting economies and short-changing future generations in a major way.

Governments from the richest countries have stated to implement policies to fight the pandemic, with an array of large-scale programmatic and policy measures. However, few developing countries are engaged in serious efforts to prevent the serious dietary challenges being faced.

DNA Nanotechnology

DNA Nanotechnology

DNA nanotechnology uses the unique molecular recognition properties of DNA and other nucleic acids to create self-assembling branched DNA complexes with useful properties. DNA is thus used as a structural material rather than as a carrier of biological information. This has led to the creation of two-dimensional periodic lattices (both tile-based as well as using the "DNA origami" method) as well as three-dimensional structures in the shapes of polyhedra. Nanomechanical devices and algorithmic self-assembly have also been demonstrated, and these DNA structures have been used to template the arrangement of other molecules such as gold nanoparticles and streptavidin proteins

Mitochondrial DNA

Mitochondrial DNA

Mitochondrial DNA is the genetic material found in mitochondria, the organelles that provide energy for cells. Mitochondria provide energy to cells, and therefore called on the musclemen.

The concepts are not easy to understand scientific biology, if people from the science background. Therefore, mitochondrial DNA data do before they know words and mitochondrial DNA.

Understanding DNAA deoxyribonucleic acid (DNA) the genetic information used in the development and function of living organisms. It is often referred to as a blueprint, because it is the genetic information of the cell components, such as proteins and RNA can be taken. Genes are sections of DNA that carries genetic information. They control the physical properties of the human body such as eye color, hair, bone thickness, construction, etc.
Understanding the mitochondria
Mitochondria are the majority of the Mitochondrion. They are rod-shaped organelles, surrounded by a membrane, is present in many eukaryotic cells. Eukaryotic cells are complex structures within the mud. Mitochondria considered powerhouses of the cell, as they take nutrients and oxygen, and break them down into the ATPS (adenosine triphosphate). This is called cellular respiration.
Mitochondrial DNA
DNA is usually present in the chromosomes in the nucleus, but mitochondria are also small amounts of DNA even if the mitochondrial DNA. The mitochondrial DNA (mtDNA) present in the cytoplasm of the cell.
Mitochondrial DNA is double stranded circular molecule, as received from the mother of all multicellular organisms. That's because, in the course of fertilization, all mtDNA from the egg. Approximately 2.10 transcripts of mtDNA in each mitochrondion. Compared with the chromosomes, the less reasonable, and the genes in a limited number. Changes in mtDNA cause maternally got the disease, and a faster aging and geriatric diseases.

Mitochondrial DNA StructureMitochondrial DNA are about 16,500 base pairs of DNA building blocks () that the very small number compared with the total DNA in cells present. The genes necessary for normal function of mitochondria. Of the 37 genes, 13 are responsible for making enzymes involved in oxidation phosphorylation, a process of oxygen and sugar to the adenosine triphosphate (ATP) production. The 14 remaining genes responsible for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA). These are known as chemical DNA Cousins, as they help to accumulate amino acids in proteins.

mtDNA has a large number of enzymes, and localization of the matrix. The proteins involved in respiration are embedded in the mitochondrial inner membrane.Mitochondria is similar to the properties of plant chloroplasts. Chloroplasts of plants with their own DNA, making them able to grow and reproduce independently.

In some metazoans, there are about 100 to 10,000 separate copies of mtDNA are present per cell. While in mammals, composed, each share mitochondrial DNA molecule 16,500 base pairs, of the 37 genes coding for 13 proteins, 22 transfer RNA (tRNA) and one for each small subunit and rRNA large. The same pattern in metazoans, but in some cases, one or more of the 37 genes are missing, and a large amount of mtDNA. Some plants large number of mtDNA types (as many as 2,500,000 base pairs per mtDNA molecule), but still mtDNAs that the same number of genes.

There are approximately 20,000 to 25,000 total genes in the human genome and genes in mitochondria among them.

DNA Microarray

DNA Microarray

A DNA microarray is a multiplex technology used in molecular biology. It consists of an arrayed series of thousands of microscopic spots of DNA oligonucleotides, called features, each containing picomoles (10-12 moles) of a specific DNA sequence, known as probes (or reporters). This can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target. Since an array can contain tens of thousands of probes, a microarray experiment can accomplish many genetic tests in parallel. Therefore arrays have dramatically accelerated many types of investigation.

In standard microarrays, the probes are attached via surface engineering to a solid surface by a covalent bond to a chemical matrix (via epoxy-silane, amino-silane, lysine, polyacrylamide or others). The solid surface can be glass or a silicon chip, in which case they are colloquially known as an Affy chip when an Affymetrix chip is used. Other microarray platforms, such as Illumina, use microscopic beads, instead of the large solid support. DNA arrays are different from other types of microarray only in that they either measure DNA or use DNA as part of its detection system.

DNA microarrays can be used to measure changes in expression levels, to detect single nucleotide polymorphisms (SNPs) , to genotype or resequence mutant genomes (see uses and types section). Microarrays also differ in fabrication, workings, accuracy, efficiency, and cost (see fabrication section). Additional factors for microarray experiments are the experimental design and the methods of analyzing the data (see Bioinformatics section).

Genetic Change

Genetic Change

During the process of DNA replication, errors occasionally occur in the polymerization of the second strand. These errors, called mutations, can have an impact on the phenotype of an organism, especially if they occur within the protein coding sequence of a gene. Error rates are usually very low 1 error in every 10–100 million bases—due to the "proofreading" ability of DNA polymerases.(Without proofreading error rates are a thousand-fold higher; because many viruses rely on DNA and RNA polymerases that lack proofreading ability, they experience higher mutation rates.) Processes that increase the rate of changes in DNA are called mutagenic: mutagenic chemicals promote errors in DNA replication, often by interfering with the structure of base-pairing, while UV radiation induces mutations by causing damage to the DNA structure.Chemical damage to DNA occurs naturally as well, and cells use DNA repair mechanisms to repair mismatches and breaks in DNA—nevertheless, the repair sometimes fails to return the DNA to its original sequence.

In organisms that use chromosomal crossover to exchange DNA and recombine genes, errors in alignment during meiosis can also cause mutations. Errors in crossover are especially likely when similar sequences cause partner chromosomes to adopt a mistaken alignment; this makes some regions in genomes more prone to mutating in this way. These errors create large structural changes in DNA sequence—duplications, inversions or deletions of entire regions, or the accidental exchanging of whole parts between different chromosomes (called translocation).

Facts about the human chromosome

Facts about the human chromosome

Human chromosome DNA that contains the part of all important information about the human essence. A chromosome is, by definition, threadlike element of DNA in the cell nucleus carrying genes, heredity in linear units. Human beings have 22 pairs of chromosomes and a pair of sex chromosomes. In addition to genes, chromosomes also contain regulatory elements and sequences nucleotides. The house of DNA-binding proteins that control the functions of DNA. It is interesting to note that the word chromosome comes from the Greek word for Chrome color. Chromosomes are so named because their properties with multi-colored paint. Structure and nature of the chromosomes varies in different types. Human chromosome is always a topic of interest to researchers working in genetics. A wide range of factors that determine the human chromosomal abnormalities are responsible for and complexity, always ask a lot of interest. Let us see some interesting information on the human chromosome.

Facts about the human chromosome

23 pairs of chromosomes of human cell nuclear. Chromosome contains a DNA molecule containing genes. A molecule consisting of three chromosomal DNA sequences needed for reproduction. About color chromosome, band structure of mitotic chromosomes is obvious. Each tape contains several pairs of nucleotides in DNA.

Human beings are sexual reproduction and somatic cells are diploid with two sets of chromosomes. One which is inherited from the mother and one from the father. Since the body cells, gametes one set of chromosomes. Crossing between chromosomes leads to the creation of a new chromosome. The newly created chromosome is inherited from a parent. This suggests that not all of our shows features derived directly from one of our parents!

There are 24 different human chromosomes, with 22 chromosomes are autosomal and the other two are sex determining chromosomes. The human autosomal chromosomes are numbered 1-22 in descending order of size. "Every person has two sets of 22 chromosomes, X chromosomes from their mother and one X and one Y chromosome from the father.

Inconsistency may contain chromosomes in cells, can cause certain genetic diseases in humans. Chromosomal abnormalities in humans are often responsible for the appearance of genetic disease to their children. Those with chromosomal abnormalities are often entities disorder only, while their children are very suffering.

The chromosomal abnormalities caused by several factors, namely, to eliminate duplication or part of chromosomes, the inversion, which is to reverse the direction of movement of chromosomes or portions of chromosomes pay cut to another chromosome.

Extra copy of chromosome 21 is responsible for the known genetic disorder called Down syndrome. The trisomy of chromosome 18 results in Edwards syndrome, which can cause death in childhood.

The lack of the fifth chromosome lead to a genetic disorder known as "CRI du chat," which means "cry of the cat. The people who are affected by the disorder are shown as cat-cry in the early days and often think retarded.

Malfunctions due to sex chromosome including Turner syndrome, where the female sexual characteristics are present, but developed, Triple-X syndrome is a syndrome xxy boys and girls, both because of dyslexia to the people affected.

Chromosomes were discovered first in plants. Van Beneden monograph on the fertilized eggs of the nematode, leading to further investigations. Later this year, said in August Weismann, the germ cells is different from the body, and discovered that the cell nucleus houses the genetic material. It also suggests that the results of fertilization in a new combination of chromosomes.

These findings are the cornerstone in genetics. Scientists have achieved a sufficient amount of information on human chromosomes and genes, but much to be discovered.

DNA-DNA Hybridization

DNA-DNA Hybridization

DNA-DNA hybridization generally refers to a molecular biology technique that measures the degree of genetic similarity between pools of DNA sequences. It is usually used to determine the genetic distance between two species. When several species are compared that way, the similarity values allow the species to be arranged in a phylogenetic tree; it is therefore one possible approach to carrying out molecular systematics.

Charles Sibley and Jon Ahlquist, pioneers of the technique, used DNA-DNA hybridization to examine the phylogenetic relationships of avians (the Sibley-Ahlquist taxonomy) and primates.Critics argue that the technique is inaccurate for comparison of closely related species, as any attempt to measure differences between orthologous sequences between organisms is overwhelmed by the hybridization of paralogous sequences within an organism's genome.DNA sequencing and computational comparisons of sequences is now generally the method for determining genetic distance, although the technique is still used in microbiology to help identify bacteria.
The DNA of one organism is labeled, then mixed with the unlabeled DNA to be compared against. The mixture is incubated to allow DNA strands to dissociate and reanneal, forming hybrid double-stranded DNA. Hybridized sequences with a high degree of similarity will bind more firmly, and require more energy to separate them: i.e. they separate when heated at a higher temperature than dissimilar sequences, a process known as "DNA melting".

To assess the melting profile of the hybridized DNA, the double-stranded DNA is bound to a column and the mixture is heated in small steps. At each step, the column is washed; sequences that melt become single-stranded and wash off the column. The temperatures at which labeled DNA comes off the column reflects the amount of similarity between sequences (and the self-hybridization sample serves as a control). These results are combined to determine the degree of genetic similarity between organisms.

DNA Repair

DNA Repair

DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1 million individual molecular lesions per cell per day.Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. Consequently, the DNA repair process is constantly active as it responds to damage in the DNA structure. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages.
The rate of DNA repair is dependent on many factors, including the cell type, the age of the cell, and the extracellular environment. A cell that has accumulated a large amount of DNA damage, or one that no longer effectively repairs damage incurred to its DNA, can enter one of three possible states:

1. Irreversible state of dormancy, known as senescence
2. Cell suicide, also known as apoptosis or programmed cell death
3. Unregulated cell division, which can lead to the formation of a tumor that is cancerous

The DNA repair ability of a cell is vital to the integrity of its genome and thus to its normal functioning and that of the organism. Many genes that were initially shown to influence life span have turned out to be involved in DNA damage repair and protection.Failure to correct molecular lesions in cells that form gametes can introduce mutations into the genomes of the offspring and thus influence the rate of evolution.

DNA forensics

DNA forensics



The sequence of all species of organisms can be identified by studying the DNA that is unique to this species. Identify individuals within the species is less accurate on the site, but if DNA sequencing technology, further development of direct comparison with the large DNA and possibly the entire genome of a viable and practical and allows you to clearly separate identity.

Identifying persons forensic scan 13 loci, or regions, which vary from person to person and use these data to create a DNA profile of the person (also called DNA fingerprinting). There is very little chance that another person with the same DNA profile of a specific set of 13 regions.

Some examples of the use of DNA for forensic identification

* Identification of the suspects, who can match DNA evidence left at the crime scene sites
* People to exclude falsely accused of crimes
* Recognition of victims of crime and natural disasters
* Establishment of paternity and other family relationships
* When determining the risk and protected species as an aid to wildlife officials can (be used for prosecuting poachers)
Detection of bacteria and other microorganisms that may contaminate air, water, soil and food
* Party organ donors with recipients in transplant programs
* Place rocks seeds or livestock
* The authenticity of food as caviar and wine

DNA is effective in identifying people?

DNA identification can be very effective if it is used to make sense. Parts should be changing the DNA sequence between the most use, in addition, the parties must be large NOK overcome the fact that the man is completely random mating.

Included in the State to investigate the crime. . .

We assume that blood is the conclusion to the scene. Type O occurs in approximately 45% of Americans. If investigators type only for ABO, finding that the suspect in a crime type O really does not talk too much.

If, in addition to the type of Ø, the suspect blond, blond and questions, you now have two pieces of evidence suggest that it was in reality. Nevertheless, there are a number of type O is a blonde.

If you are at the crime scene traces from a pair of Nike Air Jordan (unique design of the herd) and the suspect, because type O and blond, Air Jordan also works the same design of the crowd much closer to the samples of the suspect to the scene.

Thus, to collect evidence of a link in the chain, where each bit is not even a strong, but the version of each of them, very strong, we can say that they doubt that the human rights.

Since DNA is the same type of thinking, which is used, you can search for matches (on the basis of the order, or if the number of small repeating units of DNA sequences) in different locations in the human genome, one or two (even three) NOK not be sure that the right course, and thirteen sites use. Rare appearances in all twelve good that you (or perhaps the prosecutor or the jury) the strengthening of trust ( "beyond reasonable doubt") argue that human rights.

How DNA typing done?

But the tenth of a percent of DNA (about 3 million bases) differs from one person to another. Researchers can use the variable regions to create a DNA profile of the person, using samples of blood, bones, hair and other body tissues and products.

In criminal cases in question, as a rule, get samples of evidence from the crime and suspicious cases, DNA extraction and analysis of the current set of specific regions of DNA (markers).

Scientists find evidence of DNA samples through the development of small pieces of DNA (probes) that each query, and bind to complementary sequences of DNA in the sample. Creates a number of investigations related to the specific structure of the samples of human DNA. The scientists compare the DNA profiles of the law to determine appropriate evidence test sample. Mark himself, as a rule, not only for the individual, but in two samples of DNA that are similar to four or five regions, most likely that the samples of the same person.

If the sample does not match the profile, not the person placing the DNA at the crime scene.

If the nature of the suspect can be assisted in the sample. Although the likelihood that another person with the same DNA profile of a specific set of probe, the chances are very small. Q: How small probability must be convinced of the guilt or acquittal of the innocent right? Judges consider many of the materials in the jury considered in conjunction with other evidence in the case. Experts say that the technology of recombinant DNA-based forensic best of witnesses, where the probability of a correct definition in 50:50.

More probes used in DNA analysis, most likely from a template, and the occasional match, but each one must probe further increases the time and cost of testing.Recommended four to six sensors. Try to get some more conventional probes, observed John Hicks (Alabama State Department legal services). He predicted that the DNA chip technology (in thousands of short sequences of DNA data to insert a small chip) will be done much faster economic analysis using probes much larger and increases the probability of intersection of the parties.

What are some of the field of DNA technologies used in forensic investigations?

Excerpts restrictions Polymorphism (RFLP)
RFLP technique to analyze a variable length of DNA fragments resulting from digestion of DNA samples from a special type of enzymes. This enzyme, restriction endonuclease meetings on specific model of DNA sequences, known as restriction endonuclease recognition site. Creates the presence or absence of specific recognition sites in DNA of different length DNA fragments separated by electrophoresis education. Thus hybridization with DNA probes linked to the complementary sequences of DNA in the sample.

RFLP was one of the first applications of DNA analysis in forensic investigations. With the development of new and more efficient DNA-analysis techniques, RFLP is not used as much as it was before, because it requires relatively large amounts of DNA. In addition, samples of degraded environmental factors, such as dirt, and mildew, do not work well with RFLP.

PCR
Was used for chain reaction (PCR) to make millions of exact copies of DNA from biological samples. DNA amplification by polymerase chain reaction can analyze DNA from biological samples as small as a few skin cells. For RFLP, if the amount of quarter samples of DNA. The ability of PCR for amplification of small amounts of degraded DNA samples is the analysis. Care, however, should be adopted in order to prevent contamination with other biological material to identify, collect and preserve samples.

Street Analysis
SSR (str) technology is used to evaluate specific regions (loci) in the nuclear DNA. The diversity of regions, size can be used to distinguish one DNA profile from another. Federal Bureau of Investigation (FBI) uses a standard set of specific regions from 13 to St. CODIS. CODIS is a program that controls the local state and national DNA databases of convicted persons, unsolved crime scene and evidence of missing persons. The probability that two individuals of the same 13 loci of a profile in one billion.

Analysis of mitochondrial DNA
Analysis of mitochondrial DNA (mtDNA) can be used to study DNA samples can be analyzed by RFLP or size. Nuclear DNA must be extracted from the samples for use in RFLP, PCR, and size, however, mtDNA analysis uses DNA extracted from other cellular organelles mitochondria. Although adult biological samples may be missing the main cell materials, such as hair, bones and teeth, which analyzed the numbers and RFLP, could be analyzed with mtDNA. During the investigation, the case went unsolved for many years, mtDNA is extremely valuable.

All mothers are the same mitochondrial DNA to their children. This is because the mitochondria of each new embryo from the egg mother. Father's sperm contributes only nuclear DNA. Compared with the profile of mtDNA remain unknown to the profile of a potential maternal relative can be an important technique with the lack of research on human beings.

Y-chromosome analysis
Y-chromosome is passed directly from father to son, so that the analysis of genetic markers on the Y chromosome is especially useful for tracking relationships between men and for analysis of biological evidence involving multiple male contributors.

DNA-Binding Proteins

DNA-Binding Proteins

Structural proteins that bind DNA are well-understood examples of non-specific DNA-protein interactions. Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. In eukaryotes this structure involves DNA binding to a complex of small basic proteins called histones, while in prokaryotes multiple types of proteins are involved.The histones form a disk-shaped complex called a nucleosome, which contains two complete turns of double-stranded DNA wrapped around its surface. These non-specific interactions are formed through basic residues in the histones making ionic bonds to the acidic sugar-phosphate backbone of the DNA, and are therefore largely independent of the base sequence.Chemical modifications of these basic amino acid residues include methylation, phosphorylation and acetylation.These chemical changes alter the strength of the interaction between the DNA and the histones, making the DNA more or less accessible to transcription factors and changing the rate of transcription. Other non-specific DNA-binding proteins in chromatin include the high-mobility group proteins, which bind to bent or distorted DNA. These proteins are important in bending arrays of nucleosomes and arranging them into the larger structures that make up chromosomes.


A distinct group of DNA-binding proteins are the DNA-binding proteins that specifically bind single-stranded DNA. In humans, replication protein A is the best-understood member of this family and is used in processes where the double helix is separated, including DNA replication, recombination and DNA repair.These binding proteins seem to stabilize single-stranded DNA and protect it from forming stem-loops or being degraded by nucleases.
The lambda repressor helix-turn-helix transcription factor bound to its DNA target
In contrast, other proteins have evolved to bind to particular DNA sequences. The most intensively studied of these are the various transcription factors, which are proteins that regulate transcription. Each transcription factor binds to one particular set of DNA sequences and activates or inhibits the transcription of genes that have these sequences close to their promoters. The transcription factors do this in two ways. Firstly, they can bind the RNA polymerase responsible for transcription, either directly or through other mediator proteins; this locates the polymerase at the promoter and allows it to begin transcription. Alternatively, transcription factors can bind enzymes that modify the histones at the promoter; this will change the accessibility of the DNA template to the polymerase.


As these DNA targets can occur throughout an organism's genome, changes in the activity of one type of transcription factor can affect thousands of genes.Consequently, these proteins are often the targets of the signal transduction processes that control responses to environmental changes or cellular differentiation and development. The specificity of these transcription factors' interactions with DNA come from the proteins making multiple contacts to the edges of the DNA bases, allowing them to "read" the DNA sequence. Most of these base-interactions are made in the major groove, where the bases are most accessible

Ways of giving Chemotherapy

Ways of giving Chemotherapy

Depending on the type of cancer, chemotherapy can be administered orally or intravenously (directly into the vein).

* Chemotherapy Oral (swallowing tablets)

These are in the form of tablets. If the health of the patient allows, he / she is able to put them into the house. Nevertheless, regular visits to hospitals are still needed to check on the health of the patient and the response to treatment.

It is vital for making tablets directly at specified. If the t forget to take one patient at a given time he / she should call the medical staff immediately.

* Chemotherapy intravenous (directly into the vein)

Intravenous chemotherapy can be given as follows:

o The direct injection into a vein.
o By drip (intravenous infusion).
o Three or infusion pump.
o Three pumps the patient bears for several weeks or months. This is known as continuous infusion, venous infusion fadálach, or ambulatory infusion (the patient may progress during the reception of the medication resources).

There are several ways to medication in the patient. These include:

o cannula - a thin tube is inserted through the skin into the vein - usually the body that comes through the back of the hand or low hand.

o infusion (intravenous infusion) - in order to dilute the medication may be rare in the bag. The solution in the bag through a tube in the hands of patients and in the vein (intravenous infusion). Cannula will be used. The solution slowly into the vein.

Chemotherapy by pressure are generally dripping from the pump. Do not hurry the pumping of the process, instead causes the solution into the vein at constant speed in a given period - the slower the rate, the longer it will take the whole thing.

o Central line - this is a long, flexible plastic line (thin tube) to come into the center of blood vessels in the chest, near the heart. The central line is usually the body goes through the center of the chest under the skin and increases in large artery near the collarbone (clavicle). The only visible part of the length of a line from the date is a little hole in the chest.

o peripherally inserted central catheter (PICC) line - the long, thin, flexible tube that is required in a vein, usually in the arm and makes its way into a large vein in the fund is near the heart. It is like a central line, but has a different point of entry.

o portacath (implantable ports) - which, for thin soft, flexible plastic tube going into a vein. It is the port (opening) just under the skin of the fund or arm. The port on which thin rubber disc special needles to pass a medical, or taken from the blood.

Pregnancy and contraception
Many chemotherapy drugs can cause birth defects. It is important to prevent a pregnant woman chemotherapy. Since most chemotherapy drugs in oral contraceptives is important to use a barrier method of contraception such as condoms, during the entire period of chemotherapy treatment and for years after treatment completion. If you are pregnant, you should tell the medical staff immediately prior. If you fall pregnant during treatment immediately tell the medical staff.