tag:blogger.com,1999:blog-62351428109139890782024-03-05T07:37:06.956-08:00Biomolecular BlogProyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-6235142810913989078.post-72603734029910085122013-09-20T05:16:00.001-07:002013-09-20T05:24:05.499-07:00Ring Species, a lively proof of Evolution<div dir="ltr" style="text-align: left;" trbidi="on">
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<span style="font-family: Georgia, Times New Roman, serif;"><span style="background-color: white; color: #37404e; font-size: 13px; line-height: 18px;">"Ring Species" might be one of the best example of how new species are originated and diversified ... For instance, in northern California only one type of salamander are found... Going towards south, the population is geographically split by the San Joaquin Valley in central California, forming two different groups. One group that evolved near the coast became brighter and the other group gen</span><span class="text_exposed_show" style="background-color: white; color: #37404e; display: inline; font-size: 13px; line-height: 18px;">erates cryptic coloration/ camouflages. These two group can still interbreed , although the hybrid offspring can not survive for long. However, the diversification continues towards south and at southern California where the valley ends, these two group meet again. At this point, one group develop superb bright coloration and other group generate excellent camouflages... Interestingly, these two groups can no longer interbreed... Clearly, a single form of salamander at north became so diversified in their journey towards south that finally two non-interbreeding species evolved ...!</span></span></div>
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<span class="text_exposed_show" style="background-color: white; color: #37404e; display: inline; font-size: 13px; line-height: 18px;"><a href="http://www.pbs.org/wgbh/evolution/library/05/2/image_pop/l_052_05.html">Click Here</a>, for an illustration</span></span></div>
Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-59393446392649937262010-11-06T11:30:00.000-07:002010-11-15T13:30:57.021-08:00A clue for mounting better immune response against HIV !<p class="MsoNormal"><span class="Apple-style-span" style="line-height: 55px; font-size:-webkit-xxx-large;"></span></p><p class="MsoCaption"><span class="Apple-style-span" style="font-family:'Comic Sans MS';"></span></p><span class="Apple-style-span" style="font-family:'Comic Sans MS';"><p class="MsoNormal"><span class="Apple-style-span" style="line-height: 55px; font-size:-webkit-xxx-large;"><b><i></i></b></span></p><b><i><p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">Download PDF: <a href="http://www.ziddu.com/download/12552922/AclueformountingbetterimmuneresponseagainstHIV.pdf.html"><b>CLICK HERE</b></a></body></span></span></span></p><p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">
<br /></span></span></span></p><p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">Do you know that about 1 out of every 300 people infected with HIV, can build up potent immune response against the virus, thereby, do not develop AIDS ! These “HIV controller” do not even need any treatment where others continuously develop full blown AIDS and eventually die. Though our body produce antibodies against HIV, our immune system cannot compete with the virus because of it’s rapid mutation rate and several other reasons. But those “HIV controllers” can somehow generate effective immune response. This finding is, nonetheless, very fascinating because it can perhaps offer a clue to treat AIDS. <o:p></o:p></span></span></span></p> <p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">Bruce Walker, an immunologist from the Ragon Institute of Massachusetts General Hospital, first realized the clinical importance of such finding and started work with it. He and his colleagues went directly to the physicians and collected DNA sample from more than 900 HIV controllers and from about 2600 individuals with normal HIV infection. They compared both type of samples with each other, using GWAS (Genome-wide Association Study) technique, to find SNPs (Single Nucleotide Polymorphism). They had found at least 300 sites that were assumed to be associated with the regulation of HIV. As it was very laborious to work with all 300 sites, they used regression analysis and finally had selected 4 sites that are strongly linked to HIV resistance. However it was not possible for them to suggest whether these sites cause HIV immunity by themselves or by associating with others. But hopefully they have found some specific amino acids difference in the HLA-B protein sequence between controllers and individuals with normal infection. HLA-B protein is associated with the antigen presentation which is an essential step of efficient immune response. It can be assumed that the tiny change in the HLA-B protein structure due to amino acids variation,may provide scope for better antigen presentation in those controller individuals. <o:p></o:p></span></span></span></p> <p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">Researchers are yet to explain the proper mechanism of how altered HlA-B protein induce better immune response, but as always scientist are not that impatient, rather they are charged up with the finding and aimed to draw an explanation about proficient immune response and ultimately design a proper treatment procedure for AIDS</span></span><o:p></o:p></span></p><p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;">
<br /></span></span></span></p><p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"></span></span></span></p><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><p class="MsoNormal"><u><span style="line-height:115%; Comic Sans MS"font-family:";font-size:10.0pt;">Source:</span></u><span style=" line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><span style="mso-spacerun:yes"> </span></span><a href="http://www.nature.com/news/2010/101104/full/news.2010.582.html"><span style="color:black;mso-themecolor:text1;">http://www.nature.com/news/2010/101104/full/news.2010.582.html</span></a><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><o:p></o:p></span></p></span></span></span><p></p></i></b><p></p></span><p></p><p></p>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-33321380874499982372010-10-07T11:43:00.000-07:002010-10-16T13:28:49.776-07:00An Introduction to the Term "Epigenetics"<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span class="Apple-style-span" style="font-family:'Comic Sans MS';color:#333333;"><span class="Apple-style-span" style="font-size:-webkit-xxx-large;"></span></span></p><span class="Apple-style-span" style="font-family:'Comic Sans MS';color:#333333;"><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span class="Apple-style-span" style="font-size:100%;"><span class="Apple-style-span" style="font-size:13px;"><b><i></i></b></span></span></p><span class="Apple-style-span" style="font-size:100%;"><b><i><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">Who am I? What made me so different from other species? Why I share similarities with my parents? Again, why I have dissimilarities with them? And so on … ???<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">May be these are the most preceding questions which are continuously striking us from the ancient time. Answers and explanations are still ambiguous but human are always curious. The level of curiosity that we have, is massive and that’s why we are special comparing with other species. So when a question strikes us, we become energized to draw an answer. The journey of finding those answers of what we are and why we are like this, was commenced many years ago but got a way in 1865 with the discovery of rules governing the inheritance of traits in organisms by Gregor Mendel. This journey got pace with the identification of Gene responsible for this inheritance and the elucidation of DNA structure by James Watson and Francis Crick in 1953 and found its destination with Human Genome project in 2001. The production of bacterial cell whose entire genomic material is synthetic, added new dimension in bioscience. Now there is no ambiguity that we are nothing but the composition of carbon, hydrogen, oxygen, nitrogen and some other elements. Our DNA is made up with all these elements where all the information of continuing a life is stored in the language of A, T, G, C. Now we know the basis of various diseases because we realized and detected the factors responsible for those diseases. We sequenced our whole genome and identified genes those are assumed to be responsible for everything. We are controlled by genes but how these genes are controlled? One specific gene act differently from time to time on different conditions with no alteration in DNA sequences. What are the reasons behind this?<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">Charles Darwin, in his “On the Origin of Species” made it clear to us that evolutionary changes take place over many generations and through millions of years of natural selection. So, environmental factor cannot alter genetic sequence so quickly. But surprisingly sometimes some short-time events can also leave an imprint to one’s genome that also can be transmitted to his offspring! These imprints are then can short-circuit evolution. Dr. Lars Olov Bygren, a preventive-health specialist from Karolinska Institute in Stockholm conducted a research on random sample of 99 individuals born in the Overkalix parish of Norrbotten in 1905. In 19</span></span></span><sup><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">th</span></span></span></sup><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;"> century Norrbotten was so isolated that if the harvest was bad, people starved. People of Norrbotten suffered from crop failure and starvation in the year of 1800, 1812, 1821, 1836, and 1856. But they had excess harvest in the year of 1801, 1822, 1828, 1844 and 1863. From historical records Bygren and his colleagues became able to trace the parents and grandparents of those 99 samples. From agricultural records, they determined how much food had been available to their parents and grandparents when they were young. They found that the grandsons of Overkalix boys who had overeaten died an average of six years earlier than the grandsons of those who had experienced poor harvest. Their later researches revealed that their findings of shorten life span due to a single winter of gluttony are also accurate for Norrbotten females. How could these be possible?<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">Molecular biologist Arturas Petronis and his colleagues at the Center for Addiction and Mental Health in Toronto, Canada wanted to understand why identical twins, who share virtually all the same genes, could still wind up being so different. One monozygotic twin could develop diabetes or cancer or arthritis, and their co-twin, the genetically identical one, could be perfectly healthy-why? Or why autism strikes boys four times as often as girls? Lots of questions but no clear explanation from genetic perspective.<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">May be the answers lies beyond both nature and nurture which already have given birth to a new science called Epigenetics. The word “epigenetic” literally means “in addition to changes in genetic sequence.” The term has evolved to include any process that alters gene activity without changing the DNA sequence, and leads to modifications that can be transmitted to daughter cells. These patterns of gene expression are governed by the cellular material — the epigenome — that sits on top of the genome, just outside it. Environmental factors like diet, stress and prenatal nutrition can make an imprint on genes that is passed from one generation to the next.<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-style: normal;">Many types of epigenetic processes have been identified so far—they include methylation, acetylation, phosphorylation, ubiquitylation, chromatin modification etc. Epigenetic processes are natural and essential to many organism functions, but if they occur improperly, there can be major adverse health and behavioral effects. One important point is that epigenetic changes cannot be treated as Evolution. It does not change DNA sequence. Epigenetic changes are occurred in response to an environmental stress. That response can be inherited through many generations via epigenetic marks, but if the environmental pressure is removed, the epigenetic marks will eventually fade, and the DNA code will begin to slip back to its original programming with time.<o:p></o:p></span></span></span></span></p> <p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#663300;"><span class="Apple-style-span" style="font-style: normal;">Only few years ago it was thought, once we sequence the entire genome, we can explain the mystery of our uniqueness and we can eliminate various diseases, but now we are realizing only genetic code unveils very little of us. Until we understand how genes are controlled through reversible chemical modification or epigenomic marks, we cannot diminish the obscurity of our individuality. So, the International Human Epigenome Consortium (IHEC) was formed last January and projects had been set to map 1,000 reference epigenomes within a decade. However, when we successfully decipher all the epigenetic marks, we may experience another factor that needs to be resolved and that’s why, may be our journey will never end. But until then, understanding of epigenetic marks are the most challenging tasks of today’s biologists!</span></span><span class="Apple-style-span" style="font-style: normal;"><o:p></o:p></span></span></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#663300;"><span class="Apple-style-span" style="font-style: normal;"><br /></span></span></span></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;">[ The article has been collected and primarily reformed by-<span class="Apple-style-span" style=" color: rgb(51, 51, 51); font-size:medium;"><b><i><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><b><i></i></b></i></b></span></span></span></span></i></b></span></span></span></span></span></p><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><b><i><p class="MsoNormal" style="line-height: normal; display: inline !important; "><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;">Saadlee Shehreen (Undergraduate student, University of Dhaka) <span class="Apple-style-span" style=" color: rgb(51, 51, 51); font-size:medium;"><b><i><b><i></i></b></i></b></span></span></span></span></span></p><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><b><i><p class="MsoNormal" style="line-height: normal; display: inline !important; "><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;">]</span></span></span></span></p></i></b></i></b></span></span></span></span></i></b></i></b></span></span></span></span></i></b></span></span></span></span><p></p><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><p></p></i></b></span></span></span></span><p></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><b><i></i></b></p><b><i><p></p></i></b><p></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i></i></b></span></span></span></span></p><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="font-style: normal;"><span class="Apple-style-span" style="color:#000000;"><b><i><p></p></i></b></span></span></span></span><p></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#663300;"><span class="Apple-style-span" style="font-style: normal;"></span></span></span></span></p><span style="font-family:'Comic Sans MS';font-size:10pt;"><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#663300;"><span class="Apple-style-span" style="font-style: normal;"><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto; line-height:normal"><span class="Apple-style-span" style="font-size:100%;"><span class="Apple-style-span" style="font-size:13px;"><br /></span></span></p></span></span></span></span><p></p><p class="MsoNormal" style="line-height:14.4pt"><span style=" text-transform: uppercase; font-family:'Comic Sans MS';font-size:10pt;"><a href="http://www.blogger.com/post-edit.g?blogID=6235142810913989078&postID=3332138087449998237"><span style="text-decoration: none; "><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><br /></span></span> </span><span style="text-transform: none; text-decoration: none; "><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"><o:p></o:p></span></span></span></a></span></p> <p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><o:p><span class="Apple-style-span" style="font-weight: normal;"><span class="Apple-style-span" style="color:#000000;"> </span></span></o:p></span></p></i></b></span><p></p></span><p></p> <p class="MsoNormal"><span style="line-height:115%;Comic Sans MS"font-family:";font-size:10.0pt;"><o:p> </o:p></span></p>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com2tag:blogger.com,1999:blog-6235142810913989078.post-68246098852234689232009-11-27T05:15:00.000-08:002009-11-27T09:09:37.836-08:00Adult Neurogenesis<div><div><span class="Apple-style-span" style="font-family:georgia;"><i><span class="Apple-style-span" style="font-size:large;"><span class="Apple-style-span" style="color:#CC9933;">what is adult neurogensis?</span></span></i></span></div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Adult neurogenesis is the formation of new neurons in adult brain. It was a prevailing belief that mature brain can not produce new neurons.</i></span></span><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>A number of reasons behind this belief, includes</i></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>- limited capacity of self-reparing in mammal brain and spinal cord.</i></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>- structural consistency of mammalian brain throughout the life with an unchanging number of neurons of about 100 billion.</i></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Besides, </i></span></span><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>it is very difficult to imagine how new neurons could develop and integrate successfully into the mature brain structure. However ,due to scientist's arduous search for unknown and enormous technical development, many evidence are found regarding adult neurogenesis and it is now widely accepted by the scientific community.</i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="border-collapse: separate; line-height: 25px; "><span class="Apple-style-span" style="font-family:georgia;"><i><span class="Apple-style-span" style="color:#CC9933;"><span class="Apple-style-span" style="font-size:large;">Where does adult neurogenesis occur?</span></span></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Most cells in the brain are formed during embryonic and early post-natal period while new neurons are also generated throughout life and are added to at least two areas of the brain: the hippocampus ( involved in certain types of learning and memory) and the olfactory bulb</i></span></span><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i> </i></span></span><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>( involved in the sense of smell). </i></span></span><span class="Apple-style-span" style="border-collapse: separate; line-height: 19px; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>New neurons are spawned from the division of neural precursor cells — cells that have the potential to become neurons or support cells.</i></span></span></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="line-height: 19px;"><i><br /></i></span></span></div></div></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://www.jyi.org/articleimages/1643/originals/img0.jpg"><img style="cursor:pointer; cursor:hand;width: 600px; height: 310px;" src="http://www.jyi.org/articleimages/1643/originals/img0.jpg" border="0" alt="" /></a><br /><div><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="color:#CC9933;"><span class="Apple-style-span" style="line-height: normal;"><span class="Apple-style-span" style="color:#996633;">click on image to view the full image...</span>.</span></span></span></span></div><div><span class="Apple-style-span" style="font-family:georgia;color:#CC9933;"><i><br /></i></span></div><div><span class="Apple-style-span" style="font-family:georgia;color:#CC9933;"><i><br /></i></span></div><div><div><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="line-height: normal; border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>New hippocampal neurons are generated by neural precursors located in the hippocampus, in a region known as the subgranular zone. In contrast, new olfactory neurons arise from neural precursors located outside of the olfactory system, in a region known as the subventricular zone of the lateral ventricle. These cells migrate to the olfactory bulb through a tract known as the rostral migratory stream.</i></span></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><i><span class="Apple-style-span" style="font-size:large;"><span class="Apple-style-span" style="color:#CC9933;">What are the functional significance of newly synthesized neurons?</span></span></i></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Experimental studies suggest that new neurons integrate into the circuitry of the brain and actively participate in its functions. The hippocampus is known to play a critical role in learning and memory and many scientists have hypothesized that newly generated neurons within the hippocampus contribute to these processes. Although currently limited, there is support for this hypothesis. For instance, conditions that impair adult neurogenesis, such as stress, also impair learning. In contrast, conditions that promote the generation of new neurons, such a physical exercise , often are associated with improved memory and learning.</i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Studies have shown that the beneficial effect of many antidepressant are diminished when neurogenesis is blocked. Again many therapies and medication that are used to treat patients suffering from depression can cause an increase in hippocampal neurogenesis .So clearly, there is a link between adult neurogenesis and neurological disorder. We can expect, in near future neurological disorder can be cured by manipulating neurogenesis, though its still very much impossible. </i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Many studies have shown that neurogenesis is stimulated in the mammalian brain in response to injury and disease. Although this injury-induced neurogenesis does not lead to recovery, many scientists believe it represents brain's attempt to mend itself. Now, if we can understand the mechanism of neurogenesis and the integration of new neurons to nervous system its may be possible to cure or give life to a patient having severe brain stroke !!!</i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i>Once it was thought, once you were grown all you could do was watch your brain cells die. But things are changed. The discovery of life-long neurogenesis in humans has redefined the understanding of the brain and spinal cord. Lots of expectation has already been arisen with this discovery. We can suddenly hope that new strategies will be developed to treat injuries and diseases of the brain and spinal cord in future.</i></span></span></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; "><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style="font-size:medium;"><i><br /></i></span></span></span></div><div>Source:</div><div><a href="http://www.bioedonline.org/hot-topics/adult-neurogenesis.cfm">http://www.bioedonline.org/hot-topics/adult-neurogenesis.cfm</a></div></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com1tag:blogger.com,1999:blog-6235142810913989078.post-19021246303172333122009-09-05T03:47:00.000-07:002009-09-06T12:47:46.090-07:00 How new strain of influenza viruses evolve ? <div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Whenever a new version of virus evolves , there's a chance that it'll become pandemic. Its because human does not have immuno resistance against that new strain. However, the interesting Ques. is <b>how these new strains evolve?</b></span></span></div><div><div><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">New strain of virus ( like " Nobel H1N1" ) can be emerged via two basic processes.</span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>They r -</b></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>1.</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> Antigenic Shift</span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>2.</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> Antigenic Drift</span></span></div><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Antigenic shift</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> is the process by which </span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">at least</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> two different strains of a virus (or different viruses), especially influenza</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">, combine to form a new subtype having a mixture of the surface antigens</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> of the two original strains. The term </span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">antigenic shift</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">is more often applied specifically (but is not limited) to the influenza. Antigenetic shift is a specific case of reassortment</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> or viral shift</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> that confers a phenotypic</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> change.</span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Genomes of influenza virus consist of 8 distinct segments of RNA</b></span></span><span class="Apple-style-span" style="font-size:medium;"> . These segments act like mini-chromosomes, and each time a flu virus is assembled, it requires one copy of each segment. If a single host (a human, a chicken, or other animal) is infected by two different strains of the influenza virus, then it is possible that new assembled viral particles will be created from segments whose origin is mixed, some coming from one strain and some coming from another. The new reassortant strain will share properties of both of its parental lineages.</span></span></span></div></div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><span class="Apple-style-span" style="color:#333333;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPVJ5nRe22rSPUXLU5Fi4HqjVdfd_JJypBhCSiZFvK-NQ984riZGTldAHxVa-YQVm2Y74_L37KX0Q-pHEqCgxAFJyuwocsNa0jbArP493zSj67VfY02WVQwh5o2Bh_KSVNu0YmbKjJ-BM/s1600-h/antigenic+shift.jpg"><span class="Apple-style-span" style="font-size:medium;"><img style="cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPVJ5nRe22rSPUXLU5Fi4HqjVdfd_JJypBhCSiZFvK-NQ984riZGTldAHxVa-YQVm2Y74_L37KX0Q-pHEqCgxAFJyuwocsNa0jbArP493zSj67VfY02WVQwh5o2Bh_KSVNu0YmbKjJ-BM/s400/antigenic+shift.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5377978073661917826" /></span></a></span><div><span class="Apple-style-span" style="font-size:medium;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPVJ5nRe22rSPUXLU5Fi4HqjVdfd_JJypBhCSiZFvK-NQ984riZGTldAHxVa-YQVm2Y74_L37KX0Q-pHEqCgxAFJyuwocsNa0jbArP493zSj67VfY02WVQwh5o2Bh_KSVNu0YmbKjJ-BM/s1600-h/antigenic+shift.jpg"></a></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span"><span class="Apple-style-span" style="color:#660000;"><span class="Apple-style-span" style="font-size:medium;">click on the image to view it larger</span></span></span><span class="Apple-style-span" style="font-size:medium;"><br /><br /></span></span><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="line-height: normal;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style=" line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Another term </span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Antigenic drift</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><b> </b>is completely diferent and should not be confused with </span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Antigenic</b> <b>shift</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><b>. </b>Random mutations</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> in the genes of a virus drives </span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>antigenic drift</b></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> that changes the antigens </span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">of the virus. As these changes accumulate it may help the virus to evade the immune system since antigens are what the immune system</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> recognizes. </span></span></span></div><div><span class="Apple-style-span" style=" line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style=" line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Thus a new strain can evolve by the genetic changes in viral genome... !</span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="font-size:large;"><b><i><br /></i></b></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="font-size:large;"><b><i>Reference:</i></b></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><i><span class="Apple-style-span" style="font-size:medium;">http://en.wikipedia.org/wiki/Antigenic_drift</span></i></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><i><span class="Apple-style-span" style="font-size:medium;">http://en.wikipedia.org/wiki/Antigenic_shift</span></i></span></div></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-68739542168752522932009-09-02T10:19:00.000-07:002009-09-06T11:42:32.803-07:00Nobel H1N1 Swine influenza virus in brief<div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Introduction</b></span></span><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Swine influenza virus is actually a virus of pigs and its commom thoughout pig population worldwide. Transmission of this virus from pigs to human is rare and it usually can not pass from human to human. But early in this year (2009), a new strain of influenza virus is found in human (a zoonosis) which was thought to be come from pigs and its capable of spreading from human to human. This virus is classified under influenza A, subtype H1N1, generally known as the swine flu virus or </span></span><span class="Apple-style-span" style="color:#663300;"><span class="Apple-style-span" style="font-size:medium;">"nobel H1N1"</span></span><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>What does H1N1 mean actually?</b></span></span></div><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">There r 3 genera of influenza virus that cause human flu. Those r Influenza A, B and C. Influeza A is the most common cause of seasonal flu,but also there are some other strain of influenza A those are endemic in pigs and birds. </span></span><span class="Apple-style-span" style="line-height: 19px; "><a href="http://en.wikipedia.org/wiki/Influenza_A_virus" title="Influenza A virus" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;">Influenza A virus</span></span></a><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"> strains are categorized according to two proteins found on the surface of the virus: </span></span><a href="http://en.wikipedia.org/wiki/Hemagglutinin_(influenza)" title="Hemagglutinin (influenza)" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;">hemagglutinin</span></span></a><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"> (H) and </span></span><a href="http://en.wikipedia.org/wiki/Viral_neuraminidase" title="Viral neuraminidase" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;">neuraminidase</span></span></a><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"> (N). </span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">All influenza A viruses contain hemagglutinin and neuraminidase, but the structures of these proteins differ from strain to strain, due to rapid </span></span><a href="http://en.wikipedia.org/wiki/Genetic_mutation" title="Genetic mutation" class="mw-redirect" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">genetic mutation</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> in the viral genome. Influenza A virus strains are assigned an H number and an N number based on which forms of these two proteins the strain contains. 3 H and 2 N subtypes r common in human.</span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Origin</b></span></span></div><div><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">The new strain was initially described as an apparent </span></span><a href="http://en.wikipedia.org/wiki/Reassortment" title="Reassortment" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">reassortment</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> (mixing of the genetic materials of two or more viruses) of at least four strains of </span></span><a href="http://en.wikipedia.org/wiki/Influenza_A_virus_subtype_H1N1" title="Influenza A virus subtype H1N1" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">influenza A virus subtype H1N1</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">, including one strain </span></span><a href="http://en.wikipedia.org/wiki/Human_influenza" title="Human influenza" class="mw-redirect" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">endemic in humans</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">, one </span></span><a href="http://en.wikipedia.org/wiki/Avian_influenza" title="Avian influenza" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">endemic in birds</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">, and two endemic in swine. Subsequent analysis suggested it was a reassortment of just two strains, both found in swine. Although initial reports identified the new strain as swine influenza (i.e., a </span></span><a href="http://en.wikipedia.org/wiki/Zoonosis" title="Zoonosis" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">zoonosis</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> originating in swine), its origin is still not clear</span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">.</span></span></span></div><div><span class="Apple-style-span" style=" line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div></div></div><span class="Apple-style-span" style="color:#333333;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0jELpnFpJrHmyvdzl9JJ-MFZtOQre7GnsmmeSyaqvSUVOpPU5wsJoo6sI3w-OfaaTzwvtHzqBCmKaO-vngkfKeFm6fix66MlaVS6_Q7D0EjwYV-RwLBxhCQKyovNdpdhPB9QsdIkchQU/s1600-h/250px-Symptoms_of_swine_flu.svg.png"><span class="Apple-style-span" style="font-size:medium;"><img style="cursor:pointer; cursor:hand;width: 250px; height: 241px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0jELpnFpJrHmyvdzl9JJ-MFZtOQre7GnsmmeSyaqvSUVOpPU5wsJoo6sI3w-OfaaTzwvtHzqBCmKaO-vngkfKeFm6fix66MlaVS6_Q7D0EjwYV-RwLBxhCQKyovNdpdhPB9QsdIkchQU/s320/250px-Symptoms_of_swine_flu.svg.png" border="0" alt="" id="BLOGGER_PHOTO_ID_5376951175695342306" /></span></a></span><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0jELpnFpJrHmyvdzl9JJ-MFZtOQre7GnsmmeSyaqvSUVOpPU5wsJoo6sI3w-OfaaTzwvtHzqBCmKaO-vngkfKeFm6fix66MlaVS6_Q7D0EjwYV-RwLBxhCQKyovNdpdhPB9QsdIkchQU/s1600-h/250px-Symptoms_of_swine_flu.svg.png"></a></span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span><div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Who r in risk?</b></span></span></div><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Those who have lower immuno resistance ,such as children, HIV positives r very much susceptible for this virus.</span></span><span class="Apple-style-span" style="line-height: 19px; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">The U.S. </span></span><a href="http://en.wikipedia.org/wiki/Centers_for_Disease_Control_and_Prevention" title="Centers for Disease Control and Prevention" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Centers for Disease Control and Prevention</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> (CDC) noted that although this was a very serious virus, cases worldwide were usually mild, and most hospitalizations and deaths had been of persons that also had underlying conditions such as asthma, diabetes, obesity, heart disease, or a weakened immune system.</span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px;"><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style=" line-height: 19px;"><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;"><b>Vaccination</b></span></span></span></div><div><span class="Apple-style-span" style="line-height: 19px; "><a href="http://en.wikipedia.org/wiki/Vaccine" title="Vaccine" style="text-decoration: none; background-image: none; background-repeat: initial; background-attachment: initial; -webkit-background-clip: initial; -webkit-background-origin: initial; background-color: initial; "><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Vaccines</span></span></a><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;"> are available for different kinds of swine flu. Although the current trivalent influenza vaccine is unlikely to provide protection against the new 2009 H1N1 strain,</span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;">vaccines against the new strain are being developed and could be ready as early as November 2009. </span></span><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="font-size:medium;">Besides, ayurvedic experts said, tulsi pata( a herb) provide a little bit resistance against swine flu as well as any other seasonal flu. </span></span><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:medium;">But if the new virus mutated futher ,it could become more virulent and less susceptible to any new vaccines.</span></span></span></div><div><span class="Apple-style-span" style="font-size:180%;color:#666666;"><span class="Apple-style-span" style=" line-height: 19px;font-size:18px;"><i><br /></i></span></span></div><div><span class="Apple-style-span" style="font-size:180%;color:#666666;"><span class="Apple-style-span" style=" line-height: 19px;font-size:18px;"><i>reference:</i></span></span></div><div><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style=" line-height: 19px;"><i><a href="http://en.wikipedia.org/wiki/2009_flu_pandemic"><span class="Apple-style-span" style="font-size:small;">http://en.wikipedia.org/wiki/2009_flu_pandemic</span></a></i></span></span></div><div><span class="Apple-style-span" style="font-family:-webkit-sans-serif;font-size:100%;"><span class="Apple-style-span" style=" line-height: 19px;font-size:13px;"> </span></span></div></div></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-47599616491341797402009-06-15T04:42:00.000-07:002009-09-06T09:39:06.761-07:00 Cancer cells and embryonic stem cells r immortal. How they escape death ? <span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;">In 1961 ,Dr, Leonard Hayflick discovered that when cells are taken from the body and grown in tissue culture on a laboratory dish, there is a limit to how long the cell line lives . After about 50 (the num varies with the kind of tissue) divisions, the aging cell line dies. Its known as Hayflick limit. This Hayflick limit has puzzled developmental biologists for decades. What causes the cells, after so many successful divisions, to abruptly break down ? How does a cell know its time is up?</span></span><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;"><br /></span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;">But scientist now know all the answers !!!</span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;"><br /></span></span></div><span class="Apple-style-span" style="color: rgb(51, 51, 51); "><span class="Apple-style-span" style="font-size:medium;">The secret to immortality proved to be a short tag of DNA attached on the tips of the cell's chromosomes,known as telomere. This segment of DNA plays a key role in cell division. The telomere provides a place for the cell's DNA-copying machinery to latch onto the chromosome when the time comes for the chromosomal DNA to be copied into daughter chromosomes. However, every time the machinery attaches, the short bit of the telomere where the machinery sits down on the DNA is not itself copied, so the telomere gets a little shorter each time the cell divides. When the telomere reaches a minimal length after some 50 divisions, the cell can no longer replicate its DNA and lapses into senescence.</span></span><div><span class="Apple-style-span" style="color:#333333;"><br /></span></div><div><span class="Apple-style-span" style="color:#333333;"><br /></span><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); "></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjq7RkJbC5Gr3QroJSlrlIRkqEjVo67cgV-v5-mD59psCfvFgvlwnQgv5islYCn-oFmHmTKfPetTER_w_TXKqNINKl7dTiKYVhAKA1wOpASTdEPAlVoqLi1qun8rAGBOT30VW-nqsgVMGo/s1600-h/chromosome_centromere-telomere_popup.jpg"><img style="cursor:pointer; cursor:hand;width: 320px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjq7RkJbC5Gr3QroJSlrlIRkqEjVo67cgV-v5-mD59psCfvFgvlwnQgv5islYCn-oFmHmTKfPetTER_w_TXKqNINKl7dTiKYVhAKA1wOpASTdEPAlVoqLi1qun8rAGBOT30VW-nqsgVMGo/s320/chromosome_centromere-telomere_popup.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5347595424219250386" /></a><br /><div><span class="Apple-style-span" style="color:#333333;"><br /></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); "></span><div><span class="Apple-style-span" style="color:#333333;"><span class="Apple-style-span" style="color:#000000;"><br /></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size:large;">So, why Cancer and ESC cells are immortal ?</span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;"><br /></span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;">All cells possess a gene, known as the telomerase gene, which can add DNA back to the tip of telomeres. In almost all cells this gene is turned off early in development. If somehow, this gene is turned on then the cell become a cancer cell. </span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;"><br /></span></span></div><div><span class="Apple-style-span" style="font-size:medium;"><span class="Apple-style-span" style="color:#333333;">Embryonic Stem Cells also have the telomerase activity. But when they differentiate into other specialized cells they lose their telomerase activity ,as well as immortality. A few, however, are set aside, protected from the influences that trigger differentiation and shutting down of the telomerase gene. Called germ line cells, these embryonic stem cells have a fully functional telomerase gene and continue to divide, producing eggs and sperm that in their turn produce more stem cells in the next generation.</span></span></div><div><span class="Apple-style-span" style="color:#666666;"><br /></span></div><div><br /></div><div>reference :</div><div><a href="http://txtwriter.com/onscience/index.html">http://txtwriter.com/onscience/index.html</a></div><div><br /></div></div></div></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com1tag:blogger.com,1999:blog-6235142810913989078.post-864186283537969932009-06-03T01:51:00.000-07:002009-09-06T11:33:41.208-07:00Giving Birth of extincted creature !!! possible or not?<span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">The recipe for making any creature is wriitten in its DNA. If so,then its very much possible to regenerate an extincted organism from its DNA (when the complete DNA sequence of that organism is known).</span></span></span><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">Creating a living, breathing creature from a genome sequence that exists only in a computer's memory is not possible right now. But someone someday is sure to try it, predicts Stephan Schuster, a molecular biologist at Pennsylvania State University. It is only going to be possible with creatures for which we can retrieve a complete genome sequence. Without this, there is no chance,he added.</span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">Usually when a creature dies, the DNA in any flesh left untouched is soon destroyed as it is attacked by sunshine and bacteria.There are, however, some circumstances in which DNA can be preserved. If your specimen froze to </span></span><a href="http://www.newscientist.com/topic/death" alt="death" omd="zodJump('http://widgets.zibb.com/images/_jump.gif?tag=InfusionJS&url=http%3A%2F%2Fwww.newscientist.com%2Ftopic%2Fdeath&gsid=death&entitytypeid=kw&lid=http://www.newscientist.com/topic/death&title=death&intref=infusion&variantName=death&zodid=96')" class="infusionLink" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; text-decoration: none; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">death</span></span></a><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"> in an icy wasteland such as Siberia, or snuffed it in a dark cave or a really dry region, for instance, then the probability of finding some intact stretches of DNA is much higher.</span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><span class="Apple-style-span" style="color: rgb(102, 102, 102); line-height: 18px; "><span class="Apple-style-span" style="font-size: medium;">Even in ideal conditions, though, no genetic information is likely to survive more than a million years - so dinosaurs are out. "It's really only worth studying specimens that are less than 100,000 years old," says Schuster.</span></span><span class="Apple-style-span" style="font-size: medium;"><br /></span><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">The genomes of several extinct species are already being sequenced, but turning these into living creatures will not be easy . "It's hard to say that something will never ever be possible," says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, "but it would require technologies so far removed from what we currently have that I cannot imagine how it would be done."</span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">But 50 years ago, who would have believed we would now be able to read the instructions for making humans, fix inherited diseases, clone mammals and be close to creating </span></span><a href="http://www.newscientist.com/blog/shortsharpscience/2008/01/synthetic-life-watch-this-space.html" target="nsarticle" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; text-decoration: none; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">artificial life</span></span></a><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;">?</span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#666666;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size: medium;">So, its for sure , oneday something like this will be done !!!</span></span></span></div><div><span class="Apple-style-span" style="line-height: 18px; "><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="font-size: medium;">Its all about the fascinating science of Genetic Engineering and no one knows where to stop thinking !!!</span></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="line-height: 18px;"><b><i><br /></i></b></span></span></div><div><span class="Apple-style-span" style="color:#996633;"><span class="Apple-style-span" style="line-height: 18px;"><b><i><br /></i></b></span></span></div><br /><div><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><span class="Apple-style-span" style=" line-height: 18px;font-size:13px;">Reference:</span></span></div><div><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><span class="Apple-style-span" style=" line-height: 18px;font-size:13px;">http://www.newscientist.com</span></span></div><div><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><span class="Apple-style-span" style=" line-height: 18px; font-size:13px;"><br /></span></span></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-67653407254770911912009-05-28T22:09:00.000-07:002009-05-29T00:05:33.044-07:00Y chromosome is minimizing its length but will not be extincted !!! <span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;">All chromosomes in the nucleus come in pairs – except the Y chromosome. Each member of a chromosomal pair depends on its mate for genetic repair through sexual recombination. When one half suffers a genetic injury, it can discard the mutated gene and replace it with a normal copy drawn from the other member of the pair. But the Y has no sexual 'partner' with which to swap out defective genes.</span></span></span></span><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;">However,Researchers from Whitehead Institute for Biomedical Research and Washington University School of Medicine suggested that Y chromosome includes a large number of genes arranged in pairs along this single chromosome in ways that may allow the Y to mimic the paired chromosome structure of the rest of the genome.<br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;">"Genes constantly are being bombarded with little injuries – mutations. Mutations can either be beneficial or detrimental, but they are far more often detrimental," said lead researcher David Page. "On the Y, detrimental mutations cannot be discarded."<br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;">There's no question that this inability to discard has cost the Y hundreds of genes over time. Many of the chromosome's genes either have weakened or died out altogether. Sexual recombination is a card game the Y just can't win. But this new research suggests it doesn't always need to. For critical genes, it swaps with itself.<br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 21px; "><span class="Apple-style-span" style="line-height: 15px; "><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 102, 102);"><span class="Apple-style-span" style="font-size:large;"><span class="Apple-style-span" style="font-style: italic;">Rather than swapping DNA with the X, the Y may exchange DNA with itself, in a recombination process mediated by the palindromes. The palindromes contain genes, so in effect the Y could be able to repair itself, replacing bad sequence with good, suggested by David Page.</span></span></span></span></span></span><span class="Apple-style-span" style="font-size:x-small;"><br /></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 15px;"><br /></span></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5PvEP0k9SKM0mgvucn_p4xLWaBSM_96h28VRd443A47tqenHvjFn8lSAjjuuikKECfxWowYC47uw0jqmwjrgdVwMxWhop-eh_J65mYXi_1cVb5si6SK3qW3omr3lyf1UPzSwZq0DQ8PU/s1600-h/img03o5.gif"><img style="cursor:pointer; cursor:hand;width: 320px; height: 94px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5PvEP0k9SKM0mgvucn_p4xLWaBSM_96h28VRd443A47tqenHvjFn8lSAjjuuikKECfxWowYC47uw0jqmwjrgdVwMxWhop-eh_J65mYXi_1cVb5si6SK3qW3omr3lyf1UPzSwZq0DQ8PU/s320/img03o5.gif" border="0" alt="" id="BLOGGER_PHOTO_ID_5341132654691023138" /></a><br /><span class="Apple-style-span" style="font-size:x-small;"><br /></span><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 15px;"><span class="Apple-style-span" style="font-size:x-small;"><br /></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 15px;"><span class="Apple-style-span" style=" line-height: 21px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-size:medium;">"This study shows that the Y chromosome has become very efficient at preserving its important genes," said co-lead investigator Richard K Wilson. </span></span></span></span><span class="Apple-style-span" style=" line-height: 21px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-size:medium;">"It's found different ways to do the things that chromosomes must do to evolve, survive and thrive."</span></span></span></span><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(51, 51, 51); line-height: 15px;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="line-height: 15px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 102, 102);"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-size:large;">However, not all scientists r convincened by this! As Mark Jobling points out, the evolutionary cost of this mechanism is very high to occur !!!</span></span></span></span></span></span></span></div><div><br /></div><div>reference:</div><div>http://genome.wellcome.ac.uk<br /></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com2tag:blogger.com,1999:blog-6235142810913989078.post-61610225729242124552009-05-25T00:02:00.000-07:002009-05-28T23:54:24.152-07:00Men on the road to extinction !!! <div><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">Professor Jennifer Graves, a leading researcher in human sex chromosome from australia, claims the male Y chromosome was dying and could run out within the next 5 million years.</span></span></span><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></div><div><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">While at the annual outreach public lecture at the Royal College of Surgeons in Ireland, Graves said,</span></span></span></span></span><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">"You need a Y chromosome to be male." </span></span></span></span></span><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">"Three hundred million years ago, the Y chromosome had about 1,400 genes on it, and now it's only got 45 left, so, at this rate, we're going to run out of genes on the Y chromosome in about five million years. The Y chromosome is dying and the big question is what happens then," she added.</span></span></span></span></span></div><div><span class="Apple-style-span" style="font-weight: bold; line-height: 20px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"> </span></span></span></span></span><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">The male Y chromosome has a gene - SRY. SRY switches on the development of testes and pumps out male hormones that determine maleness. She said it was not known what would happen once the Y chromosome disappeared. </span></span></span></span></span></div><div><span class="Apple-style-span" style="font-weight: bold; line-height: 20px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://www.nature.com/scitable/nated/content/18935/pierce_4_10_mid_1.jpg"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><img style="cursor:pointer; cursor:hand;width: 335px; height: 188px;" src="http://www.nature.com/scitable/nated/content/18935/pierce_4_10_mid_1.jpg" border="0" alt="" /></span></span></a><div><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span><div><span class="Apple-style-span" style="font-weight: bold; line-height: 20px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><span class="Apple-style-span" style="line-height: 20px; "><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br />"Humans can't become parthenogenetic, like some lizards, because several vital genes must come from the male," she said."But the good news is certain rodent species - the mole voles of Eastern Europe and the country rats of Japan - have no Y chromosome and no SRY gene. <br /><br />"Yet there are still plenty of healthy male mole voles and country rats running around. Some other gene must have taken over the job and we'd like to know what that gene is," she added.</span></span></span></span></span><div><span class="Apple-style-span" style=" font-weight: bold; line-height: 20px;font-family:verdana;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style=" font-weight: bold; line-height: 20px;font-family:verdana;"><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></div><div><span class="Apple-style-span" style=" line-height: 20px;font-family:verdana;"><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">Earliar in 2003,Brian sykes said, time will come when Y chromosome will cease to exist. Because,</span></span></span><span class="Apple-style-span" style=" line-height: 16px; font-family:Arial;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">Over each replication hangs the threat of a random genetic mutation, which can be handed down to the next generation. Unlike other chromosomes, which are paired and can exchange genetic material with each other, the lowly Y has no duplicate from which to seek repair. Slowly but surely, Y chromosomes throughout the world are being pounded into submission</span></span><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;">.</span></span></span></span><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style="font-size: medium;"><br /></span></span></span></span><div><span class="Apple-style-span" style=" line-height: 20px;font-family:verdana;font-size:12px;"><span class="Apple-style-span" style="font-weight: bold;"><br /></span></span></div><div><span class="Apple-style-span" style=" line-height: 20px;font-family:verdana;font-size:12px;"><br /></span></div></div></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0tag:blogger.com,1999:blog-6235142810913989078.post-52733342241008499662009-05-22T03:58:00.000-07:002009-05-28T23:56:53.319-07:00Stem cells have the ability to grow into many other types of cell. if so, why its still not possible to grow a functional organ in the lab? <div><span class="Apple-style-span" style="border-collapse: collapse; line-height: 15px; font-family:'Helvetica Neue';font-size:12px;"><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; font-size:10px;"> <span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">Let's consider all of the things you would need to make an organ - say, a kidney - in a lab dish.</span></span></span></span></span></span></span></span></span></span></p><ol style="margin-top: 0px; margin-right: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 18px; list-style-type: decimal; list-style-position: initial; list-style-image: initial; margin-left: 2.2em; "><li style="margin-top: 0px; margin-right: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 10px; margin-bottom: 1em; margin-left: 5px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">First, you need to obtain a type of stem cell that can ultimately become a kidney. Would this be an embryonic stem cell? A fetal stem cell? Will an adult stem cell do the job? How do you know? Where will you get the cells?<br /><br /></span></span></span></span></span></span></span></span></span></span></li><li style="margin-top: 0px; margin-right: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 10px; margin-bottom: 1em; margin-left: 5px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">Next, you have to coax the stem cells to grow and divide in a lab dish. Which nutrients will help them grow? Do they need other types of cells around to encourage them to divide? If so, can you obtain them?<br /><br /></span></span></span></span></span></span></span></span></span></span></li><li style="margin-top: 0px; margin-right: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 10px; margin-bottom: 1em; margin-left: 5px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">After you have enough stem cells, you must simulate the physical environment required for them to differentiate into a functional kidney. How do you make the cells begin differentiating? Can you simulate the physical environment they need? Can you create a physical scaffold, or foundation, upon which the cells can shape themselves into a kidney? How will you help the developing kidney grow blood vessels to supply oxygen and nutrients to cells on the interior?<br /><br /></span></span></span></span></span></span></span></span></span></span></li></ol><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">Scientists are still years away from growing whole human organs in lab dishes - but not for lack of trying. Research groups around the world have convinced various types of stem cells to grow, divide and even differentiate in lab dishes. Most of this research is performed in stem cells obtained from other organisms, such as mice, rats and frogs.</span></span></span></span></span></span></span></span></span></span></p><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; "><span class="Apple-style-span" style="font-style: italic;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-weight: bold;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="font-family:georgia;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(102, 51, 0);"><span class="Apple-style-span" style="font-size: medium;">The final step, creating a functional organ out of differentiating stem cells, is more challenging. Obstacles to success include the problem of delivering oxygen and nutrients to cells on the inside of the organ, as well as creating physical scaffolds upon which to grow and differentiate cells.</span></span></span></span></span></span></span></span></span></span></p><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; "><span class="Apple-style-span" style=" font-style: italic;font-size:16px;"><br /></span></p><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; "><span class="Apple-style-span" style=" font-style: italic;font-size:16px;"><span class="Apple-style-span" style=""><span class="Apple-style-span" style="color: rgb(153, 153, 153);">reference:</span></span></span></p><p style="margin-top: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-bottom: 12px; margin-right: 5px; margin-left: 5px; "><span class="Apple-style-span" style=" font-style: italic;font-size:16px;"><span class="Apple-style-span" style="color: rgb(153, 153, 153);">http://learn.genetics.utah.edu</span><br /></span></p></span></div>Proyash Royhttp://www.blogger.com/profile/04317634070860870835noreply@blogger.com0