Monday, August 19, 2013

The Synthetic Cell

 The Synthetic Cell


In 2010 the James Craig Venter Institute in the US successfully created a synthetic cell. What this means is they made a genome for a cell synthetically and then injected that into a host cell, which then accepted this new DNA and continued to function and replicate as a normal cell would. This discovery could lead to improvements in many different industries around the world.

Despite sounding very simple in theory this process was actually very hard for James Venter and his team to complete. It took them 15 years in total to work through how to complete each step of the process before finally combining all of their knowledge to finally create the cell. The whole experiment is explained in length here http://www.sciencemag.org/content/329/5987/52.full. The cell that was used was no animal or anything complex like that, the cell they chose was yeast. This may seem a little odd as yeast isn’t particularly interesting but Venter’s team chose this cell due to its small genome size. After all this experiment was only a proof of concept and they were only trying to show that a synthetic cell could be made not what could be done with one.

Because of this amazing breakthrough many advancements will appear very soon in other fields. The James Craig Venter Institute has already stuck a deal with oil company Exxon Mobil to produce algae synthetically to create biofuels. This will have a huge impact upon the oil industry if there is an alternative energy source available. Another improvement that can result is a complete new process to administer vaccines. Instead of getting vaccines through a needle it could be possible to synthetically create the cells and put them inside of a pill that could be swallowed. This would make taking vaccinations much less invasive. But the institute isn’t too worried about these new advancements. They are now turning their attention to improving our understanding of what creates life inside of a cell. To do this they are going to determine which parts of DNA a cell can’t survive without and then from this they will know the absolute minimum requirements for life inside of a cell. This will change the field of genetics immensely as there is still a large amount that is unknown. This further research with the aid of synthetically altered cells could help scientists to understand exactly what each gene does inside of a cell.

This might all sound like something taken straight from a movie but I assure you this is real and is happening now. In the very near future many fields will be affected by the creation of this synthetic cell and we will be the ones who will be able to reap the rewards. This is only scratching the surface of what science will be capable of in coming years.

RNA-only genes: ancient infections hide in human genome and get themselves passed from generation to generation

 RNA-only genes: ancient infections hide in human genome and get themselves passed from generation to generation


From the Economist:

Not so long ago, received wisdom was that most of the human genome—99% of it—was “junk”. If this junk had a role, it was just to space out the remaining 1%, the genes in which instructions about how to make proteins are encoded.

That, it now seems, was far from the truth. The decade since the completion of the Human Genome Project has shown that lots of the junk must indeed have a function. Almost two-thirds of human DNA, rather than just 1% of it, is being copied into molecules of RNA. As a consequence, rather than there being just 23,000 genes, there may be millions of them.


Human chromosomes (grey) capped by telomeres (white). Image source: Wikipedia, public domain.

One new genetic class is known as lincRNAs. Molecules of lincRNA are similar to the messenger-RNA molecules which carry protein blueprints. However, they do not encode proteins. More than 9,000 sorts are known, and their job is the regulation of other genes.

LincRNA is rather odd, though. It often contains members of a second class of weird genetic object. These are called transposable elements - “jumping genes” - because their DNA can hop from one place to another within the genome. Transposable elements come in several varieties, but one group of particular interest are known as endogenous retroviruses. These are the descendants of ancient infections that have managed to hide away in the genome and get themselves passed from generation to generation along with the rest of the genes.

RNAi: Curing Genetic Disease

 RNAi: Curing Genetic Disease

Destined from conception, sufferers of genetic diseases have very poor prospects of finding cures, with most medical treatments only mitigating or slowing symptom progression, condemning them to a curtailed lifespan and reduced quality of life. With the advancement of RNA interference research, a world of possibilities may be uncovered for treatments of genetic disorders that offer effective, long-term solutions.


Autosomal disorders are nearly impossible to cure as the patient’s DNA is the origin of the disease. Both traditional and RNAi treatments attempt to manipulate gene activity or influence gene products such as protein synthesis. However, current pharmacological therapies for genetic disorders have several notable shortcomings, namely the delivery of drugs, targeting and specificity (Seyhan, 2011). Conventional drugs are commonly unable to access and target clinically relevant particles, creating so-called “undruggable” targets. Furthermore, current methodologies lack specificity, frequently unable to act upon target gene sequences without affecting other chemically similar sequences, resulting in undesired, uncontrolled “off-targeting” (Seyhan, 2011). In comparison, RNAi can theoretically be used to silence any gene with pinpoint accuracy, which greatly expands the potential reach of medicine (National Institute of General Medical Sciences, 2012).






Figure 1. Double-stranded RNA (ScienceLibraryPhoto)

Silencing of genes is in essence, sabotaging the process of protein synthesis. Specially modified viral or plasmids vectors are used to introduce double stranded RNA into target cells. Once taken into the host nucleus, the dsRNA undergoes a complex progression of chemical changes. Firstly, RNase III enzymes called Drosha cleave the introduced dsRNA into strands of 60-70 nucleotides known as precursor-microRNA or small hairpin RNA. After being transported from the nucleus to the cytoplasm, another RNase III enzyme called Dicer cleaves the precursor-microRNA to form small interfering RNA, which are 19-25 nucleotides long. The small interfering RNA binds with a protein complex named RISC, and directs the degradation of the complementary mRNA sequence produced by the host cell’s DNA. This is the crucial step which gives RNA interference one of its main advantages over conventional therapies, specificity, as RISC will only activate and destroy mRNA which matches the small interfering RNA bound to it. Degraded mRNA means the defective sequence is not translated and so the mutant protein will not be produced (Seyhan, 2011).



Figure 2. RNA interference process (Seyhan, 2011)

Theoretically, RNAi can alleviate any disorder caused or impacted by proteins, covering a wide range of diseases including HIV, Hepatitus C and Huntington’s Disease. Notably with Huntington’s where defective genes produce toxic proteins especially damaging to motor neurons, there has already been several successful trials on rodents  (National Institute of General Medical Sciences, 2012). By silencing the Huntingtin gene in mice, levels of mutant Htt proteins were reduced with notable improvements in motor function, although challenges remain in improving potency and specificity.
Figure 3. Motor function test on Rotarod (National Phenotyping Center)
Researchers have just started to uncover the potential behind this science and there have been successes with ongoing studies; however, the classic challenges in treating genetic disorders such as drug delivery, targeting and specificity are hampering the development of effective RNAi treatments. Despite this, current scientific understandings show RNAi to be a vast and promising avenue of progress.

 Bibliography
National Institute of General Medical Sciences, 2012. RNA Interference Fact Sheet. [Online] Available at: http://www.nigms.nih.gov/News/Extras/RNAi/factsheet.html [Accessed 17 March 2012].

National Phenotyping Center, 2008. Rota-rod Test. [Online] Available at: http://tmc.sinica.edu.tw/rotarod.html [Accessed 17 March 2012].

ScienceLibraryPhoto, n.d. Double-stranded RNA molecule. [Online] Available at: http://www.sciencephoto.com/media/210478/enlarge [Accessed 17 March 2012].

Seyhan, A. A., 2011. RNAi: a potential new class of therapeutic for human genetic disease. Human Genetics, 130(5), pp. 583-605.

Wasi, S., 2003. RNA interference: the next genetics revolution?. [Online] Available at: http://www.nature.com/horizon/rna/background/interference.html [Accessed 17 March 2012].

Genetics and Obesity

 Genetics and Obesity

            Obesity, classified as a chronic disease by the World Health Organization (WHO) is regarded as having irregular or excessive fat accumulation. It can be measured and quantified by examining ones body mass index (BMI), where on average, anyone over 30kg/m2 would be classified as obese (WHO 2012). Obesity is followed by a large number of health risks (including diabetes, cardiovascular diseases, cancer and more) and generally decreases life expectancy. What has been discovered recently is that genetics plays a large role in obesity, specifically the role of melanocortin 4 receptors (MC4R) and how dysfunction of the receptors can lead to an onset of obesity (Logan MG et al. 2010).
            Although obesity is commonly known to be caused by the imbalance in calorie consumption and energy output, recent research has illustrated the genetic factor that can be taken into account for certain individuals, therefore making obesity a multi-factorial disease. MC4R has largely been known to maintain energy homeostasis by regulating the body’s food intake. It does so by providing an anorexigenic signal, which is a result of the binding of an agonist (alpha-melanocyte-stimulating hormone) to the receptor, allowing one to have the sensation of being full (Logan MG et al. 2010). Due to the multiple mutations that MC4R is susceptible to some individuals will be more likely to become obese than others with the pathogenic MC4R. MC4R polymorphisms do not actually impair an individual’s rate of energy expenditure, but rather affects their appetite causing a hyperphagic state. Phenotypes that usually follow this kind of mutation include increase in fat or growth, eating disorders (binge-eating) and hyperinsulinaemia (abnormally high levels of insulin circulation). The reason that MC4R polymorphisms result in such phenotypes is largely due to the hindered functionality of the MC4 receptor (Logan MG et al. 2010). Mutated MC4R is observed to have decreased or absent ligand binding, decreased cell surface receptor expression, incorrect protein formation, and reduced signal transduction. Of these defects, those that interfere with intracellular reception (compromises the functionality and activity of the receptors) are linked to more severe forms of obesity. This allows fairly accurate predictions to be made about the onset and severity of obesity in people with pathogenic MC4R mutations. More importantly, carriers of pathogenic MC4R have an 82% chance of passing it onto their offspring, increasing the odds of being obese by almost 5 times (note that ethnicity is also a variable) (Logan MG et al. 2010). Lastly, the polymorphism or mutation that can be identified in the MC4R gene does not imply that either the mutation is involved in the pathogenesis of the disease and that the subject will have the observed phenotypes.
            There are simply too many factors that can come into account when attempting to overcome such an epidemic as obesity; however by understanding how genetics affects obesity treatments can be enhanced and diversified to create more effective treatments for patient. By being able to predict such abnormalities through the mutations of MC4R, obesity can be prevented before onset. Theorized treatments aim to suppress appetite by increasing neural sensitivity to insulin and leptin; however current research has yet to bring forth concrete solutions to this disease (Christian N 2012).

Life Without A Fingerprint : The Immigration delay disease

 Life Without A Fingerprint : The Immigration delay disease
Fingerprints have been known as the universal identification tool in the society. For example, sometimes passport is not enough to get you through the border of  several countries and your fingerprints will be recorded for identification purposes. Fingerprints are also often presented in the court as a valid evidence to identify crime suspects and put them behind bars. But have you ever imagined living without your ‘identity’? In fact, this case does exist. Such condition in the medical term is known as adermatoglyphia, where the epidermal ridges are partially/completely missing and the biometric fingerprint scanner would not be able to recognize the fingerprints (Figure 1) .




Figure 1

Apparently, adermatoglyphia is such a rare disease that only 4 families have been known to be affected by this disease, and apart from its function as an identification tool, there is not much physiological function that fingerprint is known to have. However, Sprecher et al. (2011) mentioned in this paper that the presence of fingerprints may increase the gripping ability by increasing the friction force. Whether this difference is significant or not, there is another common feature that people with adermatoglyphia would usually have. According to Sprecher et al. (2011) and Burger et al. (2009), the histological analysis of the patients he was observing all shows a reduced capacity of hands transpiration (Figure 2). In conclusion, people with adermatoglyphia would usually have lesser number of sweat glands especially around the hand area (Burger et al. 2009) .






Figure 2 : The hand transpiration test



To examine what might be the cause of this rare condition, Sprecher et al. (2011) extracted the DNA from the person affected and their relatives, also some DNA from a person whose fingerprints are present. Through a series of process of PCR and DNA sequencing, 17 genes are suspected to be the main cause of adermatoglyphia. One of those is called SMARCAD1, and the short isoform of this gene is abundantly found in the skin fibroblasts. Sprecher et al. (2011) examined closely at this particular gene, and found mutation in one of the base that composes SMARCAD1. The DNA sequencing graph showed a clear representation of the transversion, where a guanine base is replaced with an unknown nucleotide compared to the DNA sequencing result of normal person (See Figure 3).



Figure 3. The mutation noted by the red arrow



This sequence change is believed to inactivate the first exon of the gene, hence interrupts the skin formation process. As mentioned before, people with adermatoglyphia would usually be associated with reduced hand transpiration capacity, and therefore Sprecher et al (2011) speculates that this gene might also have something to do with sweat gland development. However, it has not been scientifically proven and their research was more focused on what causes the fingerprint absence in people with adermatoglyphia. Now that we know why, hopefully none of the criminals in the world would get a SMARCAD1 gene mutation – it would be very beneficial for them don’t you think!

Is creativity an illness? But then... what is an illness?

 Is creativity an illness? But then... what is an illness?

Are you creative? Do you ever feel that when your creativity strikes you become absolutely compulsive about your "inspiration," and totally depressed when, for some reason, your inspiration wanes? It always strikes me to read about how some of the most beautiful works of art were created: their creators were obsessed, compulsive, borderline dysfunctional. Gabriel Garcia Marquez sold his car and had his family live on credit for eighteen months so he could write One hundred years of solitude. Brunelleschi's obsession was the dome of Santa Maria del Fiore, Antoni Gaudi's obsession was La Sagrada Familia. It seems to me that obsessions may ruin your life (or most likely the life of your closest ones) when you have them, but they may also lead to the most wonderful things.

So, is creativity a good thing or is it an illness?

My friend and collaborator Tanmoy Bhattacharya brought to my attention an interesting BBC post that discussed the issue. The article came up in a Facebook discussion because it raised the question: "How do you define illness? When, exactly, does a behavior trespass the normality threshold and becomes an illness?" I really liked Tanmoy's take on the issue, and I asked him permission to repost it here on the blog. It's the best thing I could get since he won't do a guest blog for me. :-)

I think he raises excellent points on the complexity of the brain, its stimuli as well as its constraints. I enjoyed reading it, I hope you will too. And if after reading this you have questions for Tanmoy, go ahead and post them in the comments and I will forward them to him.

TB: In a system as complex as the brain, which interacts with such diverse environments, it is difficult to define health and disease. There has been a long standing hypothesis that certain brain functions like deductive logic and creativity are kept in check evolutionarily because the same "structure" that can give rise to very highly creative adaptations in one environment would give rise to maladaptive behavior in a different environment. The interest in the research is, therefore, understanding the architectural limits on the brain, not to stigmatize writers or expect every bipolar to pen out a story about an old man and the sea.

EEG: That's a very interesting theory. All greatest masterpieces required such great energy and dedication from their creators that these individuals had to, at some level, become unsociable, as focused as they were on their creation. I can see how, at a species level, "being socially fit" puts a constraint on the amount of time and "obsession" the brain can dedicate to a certain task.

TB: I do not believe that we yet have a definition of illness which is "biologically" meaningful. Sure, there is a diagnostic manual that tells a doctor today when to diagnose a particular mental illness, but it is more an expression of "social" reality than a "biological" reality. So, for example, the discussion of whether homosexuality is a disease is not argued on any grounds about what it does or does not do to the person, but rather whether the majority of doctors consider it within the "normal" spectrum of behavior. No wonder its classification changed from a disease to a non-disease as the social acceptability of homosexuality grew: not because such acceptance lessened the mental load on the person with the trait (it is now not considered a disease even when the person with the trait lives in a non-accepting community), but because it became "socially" acceptable as a "normal" behavior. Currently, there is a similar debate about whether bereavement distress should be considered normal even when it leads to behavior sufficiently aberrant to otherwise merit a diagnosis of clinical depression. In other words, the question is not whether the person is depressed after a loss: the question is whether it is a disease (possibly temporary like say getting the 'flu is a disease) or whether it is not a disease because it is "normal". The classification is not done based on any kind of biological reality, except whether it is considered normal; which is determined by methods of social science, not biology.

Does this concept of normality depend on a biological reality? In other words, is there a way, other than surveying doctors (the social science method), to figure out whether some one is abnormal? Remember that we know pretty much that all of us are different in many ways, if you defined me abnormal simply because I am unique (which I certainly am), then everyone would be abnormal. One could always say that one should not look at the totality (which made everyone unique), but trait by trait, and ask whether I have traits that very few other people have? Defining abnormality this way would, of course, make Picasso abnormal; but during a mass hysteria, it would classify everyone as normal. We again see that this definition fails to capture the abnormality that is relevant to defining disease.

I claim that the only way people have found to capture the relevant abnormality is by taking the design stance: human brains (and bodies) are supposed to be "for" something. When the organ (or the totality) is carrying out this function, it is normal; when it fails to carry out this function, it is abnormal. Note that this does not solve the underlying problem: someone still has to define the function, but that turns out to be an easier problem.

We could define a disease objectively as a malfunction if we could define function objectively. And, here, biology can bring an insight: the function of brains (and bodies) is to survive and use the environment, physical, biological, and social, to further the fundamental goals of long term survival of the traits. This is usually called reproduction, but it is far more subtle: for example, one can help raise grandchildren and contribute to the long term survival; under appropriate conditions, one can help other helpful members of one's community to help survival of the helpfulness trait. The mathematics is not simple, but recent work has made much of this clearer, and it is far more than pure reproduction. The part relevant to this discussion is that for a social animal this survival depends a lot on social calculations as well as other considerations.

So, then, we can define function as being able to properly calculate and take appropriate action; but that depends on the environment one faces. The same trait of fast decisive action to take the life of an unexpected person is wonderful in times of violent combat but completely malfunctional in a peaceful society. Similarly, it is easy to show that a mental make up that helps everyone, whether or not they are helpful to others, is malfunctional in the sense that it does not help its own survival except in societies that pays a high moral premium on that. Now, since most traits will find themselves in various environments, the malfunctional has to be defined as an intermediate: it should not be "fatal" in any of the environments that an individual is likely to face. But, this depends on the environments one is "likely" to face.

Given this situation, therefore, most traits tune themselves to intermediate values, because extreme values are typically extremely ill suited in some environments one is likely to face. And, all this is further constrained by the possible organization of the brain: for example, it is completely possible that the brain is composed of two parts, one that can analyze and model its environment in terms of an "open-loop" system controlled by impersonal physical laws which constrain and guide change, and a social system that can alternately assign agency (or "will") to parts of the environment. If this simple separation of thought patterns is an useful approximation, the division of resources between the two will affect a lot of behavior: a lot of resources devoted to the physical system will make one unable to understand complicated social dynamics; whereas too high a reliance on the social system might make one unable to understand that physical phenomenon often do not have wills and desires. Both of these taken to an extreme are obviously malfunctional, and, therefore, diseased: one can think of autism or schizophrenia as examples illustrating such symptoms. But, where exactly one stops being analytical and starts being high-functional autistic will depend on what environment one is defining with respect to: when the norm is highly complex social environments, one will probably classify some highly analytic people as diseased because they cannot function in society (i.e., the "mad scientist" or "computer geeks" will get classified as "mad" or "autistic"), whereas when complex physical systems but with little social structure are the norm, some people who see willful patterns in the universe will find themselves considered ill (e.g., a "religious fanatic" will be considered "mad").

So, what have we done through all this argument? We started by arguing that DSM (diagnostic manual) definitions depend on a certain standard of normal and are not objective. Through the chain of arguments, I have tried to establish that the former (i.e. dependence on the standard of normal) is inherent part of the problem, and cannot be removed except in the trivial sense that some things have never been normal. I have also argued, however, that this dependence does not need to be subjective: what is important is not what the "doctors" have experienced as normal, but rather the environments that the *person* being diagnosed has experienced and is likely to experience.

The interesting question is that supposing we take a bunch of brains and tune up their creativity (by changing whatever neurotransmitter chemistry or electrochemical connections that we need to). Now, in some environments and depending on the rest of the circuits in the brain, this will work perfectly fine and be very useful in understanding and modeling otherwise-hard-to-model systems (somewhat similar to a physical effect called "annealing"). If the same tuning is done to a different brain which does not have the same set of controls, this tuning could lead to a bipolar disorder. Basically this hypothesis would say that creativity needs to be balanced by other control systems, so any means of independent inheritance will quite often lead to getting the creativity structures without the control structures, leading to madness. Under this hypothesis, creative people are not insane, but biology would dictate that they are at a higher risk of having insane relatives (children/siblings/etc.) than less creative people.

But, there is a different possibility as well: the "control" unit hypothesized in the previous post may not be inherited much, but developed based on experiences; or its need may be dependent on the environment. In this case, the only difference between creative people and people with some forms of insanity would be the environments they have faced or will face. Creative people can then look at bipolars and paraphrase Bradford "But for the grace of environment, there go I". We do not know if either of these hypotheses are correct, but I hope I have explained why I find it interesting to ask these questions, and why the data presented in the article is consequently interesting.

Why You Should Eat Your Broccoli

 Why You Should Eat Your Broccoli



Many of us hate broccoli along with all vegetables. But, there is something different about this one along with its cruciferous kind, which includes cabbage, bok choy, and brussel sprouts. That is, it has been recently discovered that these vegetables contain a compound, sulforaphane (SFN) that has not one but two mechanisms in preventing cancer.

Historically it was believed that genetic abnormalities and mutations were the primary underlying cause for diseases. Now epigenetics has become a field of study that is recognized as having greater than or equal importance in discovering disease susceptibility. Epigenetics studies how diet, toxins and other forces can change the expression of genes without altering the DNA sequence.

Sulforaphane was found to have the ability to fight cancer despite a person’s DNA sequence. Studies have shown that it involves a mechanism called histone deacetylases or HDAC’s. This is a family of enzymes that interfere with the genes that suppress tumors. There are also HDAC inhibitors, which include the compound SFN, and these can undo this interference by restoring the essential balance in preventing cancer.
                                  

New studies by researchers in Linus Pauling institute at Oregon State University have discovered another epigenetic mechanism, DNA methylation (DNMT), which plays a similar role. These two mechanisms work together in maintaining proper cell function. As they are both influenced by sulforaphane, this compound can help to fix disruptions in these mechanisms. SFN is able to adjust the process of HDAC and DNMT so that they are in balance.

The effect of sulforaphane on DNA methylation was explored in a study published in the journal Clinical Epigenetics. It examined the methylation of the gene, cyclinD2, in prostate cancer cells. The results of the study gave insight into how SFN regulates gene expression. It demonstrated that it is an agent in preventing prostate cancer. The positive effect of SFN is not limited to prostate cancer but researchers say that the mechanisms are relevant in other types of cancers such as colon and breast cancer.

“It’s increasingly clear that sulforaphane is a real multi-tasker”, said Emily Ho, an associate professor at OSU College of Public Health and Human Sciences, “the more we find out about it, the more benefits it appears to have.” She believes that broccoli may be one of the strongest anti-cancer fighters known today.

Another study conducted at John’s Hopkins school of medicine found another health benefit of sulforaphane. It is able to kill helicobacter pylori, a bacterium that causes stomach ulcers and potentially deadly stomach cancers. It was even found to be able to kill types of helicobacter that is resistant to common antibiotics.
                             

It is certainly confirmed that broccoli is a super vegetable in having this cancer-preventing compound!

Sunday, July 14, 2013

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.

Wednesday, April 24, 2013

Gene Mapping by In Situ Hybridization


Gene Mapping by In Situ Hybridization



The previous mapping methods are indirect in that they provide information on the physical location of a gene on a particular chromosome but without actually visualizing the gene's map position. A more direct approach is in situ hybridization, which involves hybridizing DNA (or RNA) probes directly to metaphase chromosomes spread on a slide and visualizing the hybridization signal (and thus the location of the gene to which the probe hybridizes) under a microscope.

The DNA in metaphase chromosomes is denatured in place (hence, in situ) on the slide, and hybridization of a labeled probe is allowed to proceed. Methods for mapping single-copy gene sequences by in situ hybridization originally were laborious and slow, requiring long exposures of the slides under photographic emulsion to detect the location of hybridized probe that had been labeled with low-level isotopes, such as tritium. Mapping with confidence required analysis of many metaphase spreads to distinguish the real hybridization signal from background radioactivity. However, more sensitive techniques have now been developed that enable rapid detection of hybridized probes labeled non radioactively with compounds that can be visualized by fluorescence microscopy (Fig). Even in a single metaphase spread, one can easily see the position of the gene being mapped.

In combination with banding methods for chromosome identification, fluorescence in situ hybridization can be used to map genes to within 1 to 2 million base pairs (1000 to 2000 kb) along a metaphase chromosome. Although this degree of resolution is a considerable improvement over other methods, it is still substantially larger than the size of most individual genes.


Figure: Gene mapping by in situ hybridization of a biotin-labeled DNA probe for the human muscle glycogen phosphorylase gene (MGP) to a spread of human metaphase chromosomes. Location of the MGP gene is indicated by the bright spots seen over each chromatid at the site of the gene in band q13 of chromosome 11. The mapping of MGP to 11q13 also assigns the locus for McArdle disease, an autosomal recessive myoglobinuria caused by deficiency of MGP. (Photograph courtesy of Peter Lichter, Yale University)