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Sasicha Manupipatpong

Divergent evolution illuminated: Light shed on reasons behind genome differences betwee... - 0 views

www.sciencedaily.com/...120329124607.htm

trna dna evolution genome differences proteins biotechnology

shared by Sasicha Manupipatpong on 01 Apr 12 - No Cached
  • divergent evolution of the genomes of different groups of species
  • three large domains: Archaea, Bacteria and Eukarya
  • genomes of each group have evolved towards distinct structures that have favored their separation
  • ...15 more annotations...
  • connection between the function of enzymes and the composition of the genomes shed light on the evolution and structure of genes
  • analyzed the distribution and abundance of transfer RNA genes
  • structure of genomes was adapted to the activity of some enzymes, which differ for Bacteria and for Eukarya and are absent in Archaea
  • activity of these enzymes modifies tRNAs, allowing them to recognize up to three distinct codons
    • Sasicha Manupipatpong
      Sasicha Manupipatpong on 01 Apr 12
       
      Prior to the study, it was understood that tRNA's have a specific anti-codon sequence which would recognize a single mRNA codon with the complementary sequence. Does this mean that the tRNA also attaches to different amino acids as well? How does the tRNA differentiate between the different amino acids it is at that moment carrying and the codon it matches with on the mRNA--does it change shape according to which amino acid is attached to it?
  • activity of the bacterial and eukaryal enzymes is different, which explains why the genomes and the gene composition of bacteria, eukarya, and archaea have diverged
  • relation between genome structure and the speed of protein synthesis from its genes
  • demonstrates how organisms have evolved in a different manner to achieve better adaptations and to have optimum protein translation efficiency
  • biotechnology as the discovery of the relevance of these modifications will allow an improvement in the industrial production of proteins
  • another parameter with which to optimize the synthesis of proteins from a gene
  • human insulin is "manufactured" in bacteria and our discovery would allow this production to be increased if we take into account the activity of these enzymes
  • relevant for the study of cancer: "it is possible that these modification enzymes are over-represented in some kinds of cancer. In fact, this would be logical because cancer cells are highly efficient in producing proteins."
  • greater the abundance of a protein in a cell the higher the number of triplets found in its gene sequence that can be read by modified tRNAs
  • don't exactly know why these enzymes appear or why they are different in bacteria and in eukaryotes but it's clear that they contribute to the separation of genomes of these two groups
  • genetic code is the same
  • what has changed is the relative importance of different codons of the code
  • Sasicha Manupipatpong on 01 Apr 12
     
    A recent study uncovers the reasons for the divergent evolution of the genomes of different species. The findings provide information about tRNA modifications which may prove useful in the field of biotechnology, specifically in the industrial production of proteins
wasin kusakabe

Athletic frogs have faster-changing genomes - 0 views

www.sciencedaily.com/...120412182332.htm

DNA Genomes Athletic Frogs

shared by wasin kusakabe on 14 Apr 12 - No Cached
    • wasin kusakabe
      wasin kusakabe on 14 Apr 12
       
      Physical activities can change the DNA sequence which can be passed on to later generations. However this has only been tested on frogs and may not apply to mammals like us.
  • athletic frogs tended to have faster-changing genomes.
  • Stretches of DNA accumulate changes over time
  • ...3 more annotations...
  • Physically fit frogs have faster-changing genomes
  • During exercise, the circulatory system provides blood and oxygen to the tissues that are needed most
  • When physical activity has stopped, the rush of blood and oxygen when circulation is restored to those tissues produces a burst of free radicals that can cause wear and tear on DNA, eventually causing genetic changes that -- if they affect the DNA of cells that make eggs or sperm -- can be passed to future generations.
Nitchakan Chaiprukmalakan

Biotechdaily - Low MicroRNA Activity Characterizes Inflamed Lung Tissues - 0 views

www.biotechdaily.com/...zes_inflamed_lung_tissues.html

shared by Nitchakan Chaiprukmalakan on 13 Apr 12 - No Cached
  • A recent study examined the interaction between a specific microRNA (miRNA) and the activity of the inflammatory cytokine interleukin 13 (IL-13).
  • In the current study, investigators at the Cincinnati Children's Hospital Medical Center (Ohio, USA) examined the effect that stimulation of IL-13 activity has on microRNAs, particularly miR-375
  • They reported in the March 28, 2012, online edition of the journal Mucosal Immunology that IL-13 induced changes in epithelial gene and protein expression including the consistent downregulation of miR-375 in IL-13 stimulated human esophageal squamous and bronchial epithelial cells.
  • ...3 more annotations...
  • Analysis of miR-375 levels in a human disease characterized by IL-13 overproduction - the allergic disorder eosinophilic esophagitis (EE) - revealed downregulation of miR-375 in EE patient samples compared with control patients. Low levels of miR-375 expression levels indicated disease activity.
  • “MiR-375 is proof of principle that microRNAs are involved in fine-tuning IL-13-mediated responses, which opens up a set of new possibilities for novel therapeutic targets for treatment of allergic disease.”
  • “The identification of a microRNA that regulates IL-13-induced changes and inflammatory pathways is a significant advancement for the understanding and future treatment of allergic disease,
Nitchakan Chaiprukmalakan

Proteins and quantum transition: Instant shape-shifting - 0 views

scitechstory.com/...nsition-instant-shape-shifting

shared by Nitchakan Chaiprukmalakan on 13 Apr 12 - No Cached
  • The genetic code in DNA provides the template to manufacture protein into all the cells of an organism.
  • Proteins are made by stringing together amino acids. For general purposes there are twenty amino acids in protein and they can be put together in endless combinations, some in short chains (yeast averages 466 amino acids), some long chains (titins have nearly 27,000 amino acids) and everything in-between. The pattern of amino acids determines much of the functionality of the protein.
  • Proteins are three-dimensional puzzle pieces. They are generally very complicated in shape. Even a small protein of only 100 amino acids can theoretically have 10^100 (ten to the hundredth power) different configurations.
  • ...7 more annotations...
  • most protein reconfigurations occur in nanoseconds
  • In research on proteins, it was assumed (given their chemical composition) proteins would uniformly fold as they cool down and unfold as they heat up. (Think of a balloon expanding and shrinking with the temperature of the air inside.) The experiments didn’t bear this out; the rate of folding or unfolding according to temperature change was unequal (asymmetric) and uneven (nonlinear).
  • In recent biochemistry a great deal of work is done with ‘tagging’ or ‘marking’ molecules with fluorescent and phosphorescent materials. It’s well known that fluorescence and phosphorescence are phenomena closely related to protein folding and they can only be understood in terms of quantum transition between molecules.
  • With a quantum transition, the protein could change configuration by ‘jumping’ – skipping all the transition steps – to the final configuration. They call this quantum folding and they developed a mathematical model that shows how the folding, which is virtually instantaneous, would react to change in temperature.
  • Their quantum transition model matched the folding curves for 15 different proteins and also provides an explanation for the different rates of folding and unfolding among these proteins.
  • Luo and Lu’s paper is short, a mere 16 pdf pages, and the model is unpretentious mathematically. (Luo has several other related papers on arXiv.) It comes from unknown researchers in an unknown corner of the academic world, and it’s published on the open-source arXiv system. The lack of pedigree means that it will take more time than usual for scientists around the world to learn of it, examine it, and possibly test it.
    • Nitchakan Chaiprukmalakan
      Nitchakan Chaiprukmalakan on 13 Apr 12
       
      This is not accepted as a true fact yet and has to be proven.
Nitchakan Chaiprukmalakan

How a single gene mutation leads to uncontrolled obesity - 0 views

www.sciencedaily.com/...120318143904.htm

shared by Nitchakan Chaiprukmalakan on 13 Apr 12 - No Cached
  • Researchers at Georgetown University Medical Center have revealed how a mutation in a single gene is responsible for the inability of neurons to effectively pass along appetite suppressing signals from the body to the right place in the brain.
  • The research team specifically found that a mutation in the brain-derived neurotrophic factor (Bdnf) gene in mice does not allow brain neurons to effectively pass leptin and insulin chemical signals through the brain. In humans, these hormones, which are released in the body after a person eats, are designed to "tell" the body to stop eating. But if the signals fail to reach correct locations in the hypothalamus, the area in the brain that signals satiety, eating continues.
  • He has found that the gene produces a growth factor that controls communication between neurons.
  • ...5 more annotations...
  • The Bdnf gene generates one short transcript and one long transcript. He discovered that when the long-form Bdnf transcript is absent, the growth factor BDNF is only synthesized in the cell body of a neuron but not in its dendrites. The neuron then produces too many immature synapses, resulting in deficits in learning and memory in mice. Xu also found that the mice with the same Bdnf mutation grew to be severely obese
  • large-scale genome-wide association studies showed Bdnf gene variants are, in fact, linked to obesity.
  • both leptin and insulin stimulate synthesis of BDNF in neuronal dendrites in order to move their chemical message from one neuron to another through synapses. The intent is to keep the leptin and insulin chemical signals moving along the neuronal highway to the correct brain locations, where the hormones will turn on a program that suppresses appetite.
  • "If there is a problem with the Bdnf gene, neurons can't talk to each other, and the leptin and insulin signals are ineffective, and appetite is not modified
  • One possible strategy would be to produce additional long-form Bdnf transcript using adeno-associated virus-based gene therapy, Xu says. But although this kind of gene therapy has proven to be safe, it is difficult to deliver across the brain blood barrier,
nidthamsirisup

Epigenetics: DNA Isn't Everything - 0 views

www.sciencedaily.com/...090412081315.htm

epigenetics genetics gene

shared by nidthamsirisup on 15 Apr 12 - Cached
  • Research into epigenetics has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring.
  • A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the embryos, which are normally nurtured at 25 degrees Celsius, is briefly raised to 37 degrees Celsius, the flies later hatch with red eyes.
  • crossed the flies for six generations. In this experiment, they were able to prove that the temperature treatment changes the eye colour of this specific strain of fly, and that the treated individual flies pass on the change to their offspring over several generations. However, the DNA sequence for the gene responsible for eye colour was proven to remain the same for white-eyed parents and red-eyed offspring.
  • ...7 more annotations...
  • Epigenetics examines the inheritance of characteristics that are not set out in the DNA sequence.
  • important factors are the histones, a kind of packaging material for the DNA, in order to store DNA in an ordered and space-saving way. It is now clear that these proteins have additional roles to play. Depending on the chemical group they carry, if they are acetylated or methylated, they permanently activate or deactivate genes.
  • New methods now allow researchers to sometimes directly show which genes have been activated or deactivated by the histones
  • The genetic information of the DNA is passed on along with the relevant epigenetic information for the respective cell type.
  • A similar question remains for the inheritance of the epigenetic characteristics from parents to offspring. They now know that when the gametes are formed, certain epigenetic markers remain and are passed on to the offspring. The questions, which are currently being researched, are how much and which part of the epigenetic information is preserved and subsequently inherited.
  • Diet and epigenetics appear to be closely linked. The most well known example is that of the Agouti mice: they are yellow, fat and are prone to diabetes and cancer. If Agouti females are fed with a cocktail of vitamin B12, folic acid and cholin, directly prior to and during pregnancy, they give birth to mainly brown, slim and healthy offspring. They in turn mainly have offspring similar to themselves.
  • Environmental factors, which change the characteristics of an individual and are then passed on to its offspring, do not really fit into Darwin’s theory of evolution. According to his theory, evolution is the result of the population and not the single individual. “Passing on the gained characteristics fits more to Lamarck’s theory of evolution”, says Paro.
orasa sukmark

Junk DNA Can Revive and Cause Disease, Study Finds - NYTimes.com - 0 views

www.nytimes.com/...20gene.html

shared by orasa sukmark on 30 Mar 12 - No Cached
  • can rise from the dead like zombies
  • dead gene come back to life and cause a disease
  • a dead gene come back to life and cause a disease.
  • ...16 more annotations...
  • Some of those genes, surprised geneticists reported Thursday, can rise from the dead like zombies, waking up to cause one of the most common forms of muscular dystrophy.
    • adisa narula
      adisa narula on 30 Mar 12
       
      Do these genes revive automatically?
  • It is a dominant genetic disease.
  • people who have the disease cannot smile.
  • FSHD affects about 1 in 20,000 people
  • function, if any, is largely unknown.
  • function, if any, is largely unknown
  • FSHD, is one of the most common forms of muscular dystrophy.
  • in a way FSHD was the easy case — it is a disease that affects every single person who inherits the genetic defect. Other diseases are more subtle, affecting some people more than others, causing a range of symptoms.
  • The dead gene was also repeated on chromosome 10, but that area of repeats seemed innocuous, unrelated to the disease. Only chromosome 4 was a problem.
  • chromosome 4 was a problem.
  • No one whose dead gene was repeated more than 10 times ever got FSHD
  • it was not completely inactive. It is always transcribed
  • copied by the cell as a first step to making a protein.
  • But the transcriptions were faulty, disintegrating right away. They were missing a crucial section, called a poly (A) sequence, needed to stabilize them.
  • But the transcriptions were faulty, disintegrating right away. They were missing a crucial section, called a poly (A) sequence, needed to stabilize them.
  • extra copies change the chromosome’s structure, shutting off the whole region so it cannot be used.
pet-chompoo sa-ngarmangkang

Artificial Liver - 1 views

biology.about.com/...aa040899.htm

shared by pet-chompoo sa-ngarmangkang on 01 Apr 12 - No Cached
  • pet-chompoo sa-ngarmangkang on 01 Apr 12
     
    Artificial Liver Dateline: 04/08/99 The Extracorporeal Liver Assist Device, or ELAD, is the first artificial liver to use cells from humans rather than from pigs. The device is used to sustain patients awaiting a liver transplant or whose own liver is not functioning and needs to recover.
chanon chiarnpattanodom

Chimeric green fluorescent protein-aequorin as bioluminescent Ca2+ reporters at the sin... - 1 views

www.pnas.org/...7260.full

shared by chanon chiarnpattanodom on 16 Apr 12 - No Cached
    • chanon chiarnpattanodom
      chanon chiarnpattanodom on 16 Apr 12
       
      Experiment on Ca2+ reaction with a protein aequorin. Aequorin can be found in jellyfish, when in contact with Ca2+ will emit light. Using the gene that contributes to this protein, make a similar protein emitting another wavelength of light.
Sea Maskulrath

Changes in gene expression causes high BP in pregnancy - 1 views

zeenews.india.com/...igh-bp-in-pregnancy_16515.html

epigenetics DNA human

shared by Sea Maskulrath on 16 Apr 12 - No Cached
  • Washington: Researchers have discovered that changes in the gene expression of a key enzyme may contribute to high blood pressure and increase susceptibility to forming blood clots in pregnant women with preeclampsia.
  • Epigenetics refers to changes in gene expression that are mediated through mechanisms other than changes in the DNA sequence.
  • The VCU team reported that thromboxane synthase – an important inflammatory enzyme – is increased in the blood vessels of expectant mothers with preeclampsia.The thromboxane synthase gene codes for this enzyme, which is involved in several processes including cardiovascular disease and stroke. This enzyme results in the synthesis of thromboxane, which increases blood pressure and causes blood clots.
  • ...5 more annotations...
  • According to Walsh, one of the main epigenetic mechanisms is methylation of the DNA, which controls the expression of genes. The increase of
  • his enzyme in the blood vessels is related to reduced DNA methylation and the infiltration of neu
  • enzyme
  • trophils
  • trophils into the blood vessels. Neutrophils are white blood cells that normally help fight infection.
Sasicha Manupipatpong

Memory in adults impacted by versions of four genes - 2 views

www.sciencedaily.com/...120415151347.htm

genes alzheimer's hippocampus shrinking

shared by Sasicha Manupipatpong on 16 Apr 12 - No Cached
  • advanced understanding of the genetic components of Alzheimer's disease and of brain development.
  • understanding of the genetic components of Alzheimer's disease and of brain development
  • certain versions of four genes may speed shrinkage of a brain region involved in making new memories
  • ...12 more annotations...
  • hippocampus, normally shrinks with age, but if the process speeds up, it could increase vulnerability to Alzheimer's disease
  • two genes associated with intracranial volume -- the space within the skull occupied by the brain when the brain is fully developed in a person's lifespan
  • gene variants identified in the first study do not cause Alzheimer's, but they may rob the hippocampus of a kind of "reserve" against the disease
  • cause cell destruction and dramatic shrinkage of this key brain site
  • almost twice the Alzheimer's risk if he or she had these versions of the gene
  • if a person with one of these variants did get Alzheimer's, the disease would attack an already compromised hippocampus and so would lead to a more severe condition at a younger age than otherwise
  • Alzheimer's disease causes much of its damage by shrinking hippocampus volume
  • loses a greater-than-average amount of volume due to the gene variants we've identified, the hippocampus is more vulnerable to Alzheimer's
  • associations impacting intracranial volume, which is an indirect measure of the size of the brain at full development.
  • brain volume and intracranial volume are both highly heritable
  • no associations for brain volume
  • one of these genes has played a unique evolutionary role in human development, and perhaps we as a species are selecting this gene as a way of providing further advances in brain development
  • Sasicha Manupipatpong on 16 Apr 12
     
    The shrinking of the hippocampus, which occurs with age in normal people, was found to be accelerated by certain versions of four genes, which could increase susceptibility to Alzheimer's disease, which also affects the volume of the hippocampus.
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