A hidden genetic code

first_imgHarvard scientists say they’ve solved a mystery that’s nearly as old as science’s understanding of the genetic code.Though the genetic code, the cell’s set of rules for transcribing DNA into RNA and translating RNA into proteins, has been understood for decades, scientists have puzzled over what seemed like a mathematical incongruity in the system. To manufacture proteins, cells rely on RNA, which like DNA is made up of nucleotides that have one of four bases. Cells “read” those bases in groups of three to translate RNA into  amino acids, which are used to build proteins.While there are 64 possible ways to combine four bases into groups of three, called codons, the translation process uses only 20 amino acids. To account for the difference, multiple codons translate to the same amino acid. Leucine, for example, can be encoded in six ways.Scientists, however, have long speculated whether those seemingly synonymous codons truly produced the same amino acids, or whether they represented a second, hidden genetic code. Harvard researchers have deciphered that second code, and the answer may hold hope for developing new techniques to combat resistant bacteria.As described in a paper published online in the Proceedings of the National Academy of Sciences on Dec. 31, Arvind R. Subramaniam, a postdoctoral fellow in molecular and cellular biology, and Philippe Cluzel, professor of molecular and cellular biology and Gordon McKay Professor of Applied Physics, show that those seemingly synonymous parts of the genetic code are anything but. Under some stressful conditions, the researchers found, certain sequences manufacture proteins efficiently, while others — which are ostensibly identical — produce almost none.“It’s really quite remarkable, because it’s a very simple mechanism,” Subramaniam said. “Many researchers have tried to determine whether using different codons affects protein levels, but no one had thought that maybe you need to look at it under the right conditions to see this.”The first step, Subramaniam said, involved creating multiple copies of a gene that manufactures a fluorescent protein. To understand how the synonymous parts of the genetic code affect protein production, each version of the gene was designed to use a single way to code for a specific amino acid. In the case of serine, which can be encoded six ways, researchers created six versions of the gene. Those genes were then inserted into E. coli bacteria. Next, the E. coli bacteria experienced a stressful change in their environment. They were starved of amino acids, and the results were startling.“What we found was that if the bacteria are in an environment where they can grow and thrive, each synonymous codon produces the same amount of protein,” Subramaniam said. “But the moment we put them in an environment where they are starved of an amino acid, some codons produce a hundredfold more proteins than others.”The difference, he said, lay with molecules called transfer RNA, or tRNA, which ferry amino acids to the cellular machinery that manufactures proteins.“What we found was that some of these tRNA molecules are much more efficient at being loaded with amino acids, while others are less so,” Subramaniam said. “If these tRNA molecules can’t deliver the amino acid to where it needs to be, the cell cannot manufacture the proteins it needs. In an environment where amino acids are in short supply, that ability to hold onto them becomes very important.”While the system helps cells to make certain proteins efficiently under stressful conditions, it also acts as a biological failsafe, allowing the near-complete shutdown in the production of other proteins as a way to preserve limited resources.Given the universal nature of the genetic code — the system works the same way for all organisms, from single-celled bacteria to human beings — Subramaniam hopes to explore what role, if any, differences in the seemingly synonymous portions of the genetic code may have in other organisms, and whether those differences can be exploited by researchers.“One area that I’m interested in exploring is cancer,” he said. “We know that cancer cells grow very fast. As a result, they consume most of the amino acids in their environment. The question is whether this code plays any role in the disease. And if cancer cells do use the differences between these codons to express some protein it needs to survive, can we exploit that to combat the disease?”last_img read more

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In his own works

first_imgBound in handsome red leather with gold-trimmed pages, the 1623 First Folio of Shakespeare rests in its own display case at Houghton Library’s Edison and Newman Room, a precious gem in a new exhibit marking the 400th anniversary of the Bard’s death.It couldn’t be any other way.A copy of the First Folio of “Mr. William Shakespeare’s Comedies, Histories, and Tragedies” sold at a Christie’s auction for about $6 million in 2011, but the value of the works inside cannot be measured in money.The First Folio contained 36 plays, including 18 that had never been printed before — “Macbeth,” “The Tempest,” “Julius Caesar,” and “Twelfth Night,” among them. Edited seven years after his death by his friends and fellow actors John Heminges and Henry Condell, the volume secured Shakespeare’s colossal place in Western literature.“Were it not for the First Folio, 18 plays would not have come to us,” said Peter Accardo, programs coordinator at Houghton. “Half of the Shakespearean canon would be lost.”Along with the First Folio — one of 230 existing copies — “Shakespeare: His Collected Works” includes 80 rare objects drawn from Houghton and other libraries. The exhibit runs though April 23.Early Shakespeare publications are also on display. Among them is playwright and poet Nicholas Rowe’s “The Works of Mr. William Shakespeare” (1709), which modernized punctuation and spelling and divided plays into acts and scenes. This was the first publication of Shakespeare available to Harvard students, listed in the library catalog in 1723.Visitors to the exhibit will find a volume from 1609 open to the famous sonnet with the even more famous first line, “Shall I compare thee to a summer’s day?” A 1598 edition of one of the early comedies, “Love’s Labour’s Lost” sits next to a 1608 edition of “King Lear.” Also featured is the Third Folio, published in 1664, which includes the play “Pericles,” the authorship of which is considered apocryphal.,With his insight into the tragedies and absurdities of the human condition, Shakespeare influenced generations of writers. The exhibit highlights his impact through work by e.e. cummings, Emily Dickinson, and Ralph Waldo Emerson, who called Shakespeare “master of the revels to mankind.”Because Shakespeare cannot be fully understood without performance, the exhibit showcases stagecraft and theatrical memorabilia linked to famous Shakespearean actors, such as a handkerchief used by Uta Hagen in the role of Desdemona in a 1943 Broadway production of “Othello,” and a rapier used by Edwin Booth as Hamlet in a mid-19th-century performance.Also shown is a promptbook that belonged to British actor Sir Ian McKellen, who performed the one-man show “Acting Shakespeare” in Boston in 1987. He wrote his impressions with a quick sentence: “The returns were excellent” but “the theater was dirty.”Harvard’s latest celebration of Shakespeare’s legacy includes a role for Stephen Greenblatt, the John Cogan University Professor of the Humanities and author of “Will in the World.” Greenblatt will deliver a lecture titled “Editing Shakespeare for the Digital Age” at 5:30 p.m. Tuesday at the Thompson Room, Barker Center.last_img read more

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Steven Smith closer than ever to matching Bradman

first_imgAUSTRALIA captain Steven Smith is closer than ever before to matching Don Bradman as the top-rated batsman of all-time, according to the ICC rankings for Test batsmen.Smith, who scored 239 to lead Australia to regaining the Ashes in Perth, increased his ratings points tally from 938 to 945 at No. 1, surpassing his previous best of 941 after the first Ashes Test in Brisbane.He is second on the all-time list along with former England batsman Len Hutton, and no one else apart from Bradman – who has 961 points – has ever achieved a higher tally.Smith earned seven points after his performance at the WACA led Australia to victory by an innings and 41 runs, overtaking the highest career tallies of Peter May, Ricky Ponting and Jack Hobbs.His Test batting average of 62.32 is only behind Bradman’s 99.94 on the list of best averages for batsmen who have played at least 20 innings.And he’s number one currently ahead of India captain Virat Kohli by 52 ratings points. By the time the Boxing Day Ashes Test begins, Smith would have been at the No. 1 ranking for two years.Reflecting on his double century, Smith said he had never felt better at the crease than the first part of his innings on the second day. “I think that first night I was on, as you say,” he told ABC Radio. “I was in the zone, and everything hit the middle of the bat. I felt incredibly good … that first night was probably as good as I’ve felt.”Smith currently has 426 runs at 142.00 in the Ashes which also included his unbeaten 141 which set up Australia’s opening victory in Brisbane. Darren Lehmann, Australia’s coach, said Smith has taken his game to a new level.“He’s running pretty hot isn’t he? I’ve been lucky enough to see all of his Test hundreds. So for me, seeing him evolve from that first Test hundred at the Oval to now – he just changes his own plans to what the bowlers are doing and what the wicket’s doing, and what the game needs. He’s gone to another level, which is pleasing.” (ESPN Cricinfo)last_img read more

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‘Make Immunization Strategies Practical Nationwide’

first_imgA prominent Liberian epidemiologist has urged civil society groups to make immunization strategies practical nationwide.Mr. Raymond Toupiley, Data Manager of the World Health Organization’s (WHO) Expanded Program on Immunization (EPI) gave the caution last Tuesday at the first General Assembly of the Liberia Immunization Platform (LIP) in Monrovia.The LIP is an organization comprising 22 civil society groups, championing the mass immunization of children and child-bearing mothers nationwide.EPI’s Data Manager Toupiley also urged the LIP leadership to push for inclusion in the World Health Organization, in order for the entity to exhibit swift responses to the immunization program of the country.He said that Liberia’s southeastern counties have exhibited poor performance in terms of immunization coverage owing to enormous factors.Mr. Toupiley intimated that some of the factors associated with poor immunization coverage are due to bad road conditions and also because people are not taking the initiative to spearhead vital medical programs.He reminded the LIP staff that it is one of the responsibilities of civil society groups to ensure that community dwellers take part in immunization programs of children and child-bearing mothers in the country.Mr. Toupiley acknowledged, however, that the entity since 2008 has been able to achieve at least 88% of immunization coverage.He however said that owing to the current spread of the deadly Ebola Virus Disease (EVD) in Liberia, such achievements have suffered setbacks, declining in several parts of the country.Mr. Toupiley disclosed that Liberia is at 70% immunization coverage and that three of Liberia’s rural counties are far below the performance radar, in terms of immunization of children and child-bearing mothers.“After the Ebola virus crisis in Liberia, LIP has a greater role and responsibility and we don’t want the staff to sit in these offices but go out into the field to work,” Mr. Toupiley said.“Work out your immunization plans and we’re ready to share all the great and good information with you in order to vaccinate all our children wherever they are in our war-affected country,” Mr. Toupiley emphasized.He further admonished LIP and its members to not take sides in immunization initiatives, saying that immunization is aimed at rendering services to the future generation of Liberian children.Catholic Relief Service (CRS) Liberia’s Senior Advisor Raymond Studer described the first LIP General Assembly as a significant event, saying that he was happy that over 25 Liberian civil society groups had come together to work out plans.“Frankly, I wish to let you all know that you people are doing what I’m doing as a local partner in the immunization process of Liberia,” Mr. Studer asserted.He explained that the CRS is principally interested in empowering communities in Liberia, especially in the vital and all-important health sector of the nation.In remarks, the United States Agency for International Development’s (UASID) Representative on immunization, Mr. Stephen Sizi, thanked LIP staff for considering USAID in the immunization program.Mr. Sizi told the audience and staff of LIP that working on child survivor issues is indeed a challenge and such endeavors should be approached with concerted efforts and a sense of collective endeavor, regardless of which country you are from.Mr. Sizi stressed that the participation of grassroots organizations is important and that LIP must place itself in a cardinal role to fulfill this need nationwide.For her part a Commissioner of the National Aid Commission (NAC), Mrs. Juineta Ramertz, noted that she regrets the huge impact the Ebola virus Disease (EVD) has had on the HIV-Aids program of the country.“We will systematically assess all the sectors and communities the deadly Ebola virus has impacted across the country,” Commissioner Ramertz said.Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)last_img read more

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