The beginning sentence of an article in Current Biology1 can’t help but grab your attention:Imagine trying to stuff about 10,000 miles of spaghetti inside a basketball. Then, if that was not difficult enough, attempt to find a unique one inch segment of pasta from the middle of this mess, or try to duplicate, untangle and separate individual strings to opposite ends. This simple analogy illustrates some of the daunting tasks associated with the transcription, repair and replication of the nearly 2 meters of DNA that is packaged into the confines of a tiny eukaryotic nucleus. The solution to each of these problems lies in the assembly of the eukaryotic genome into chromatin, a structural polymer that not only solves the basic packaging problem, but also provides a dynamic platform that controls all DNA-mediated processes within the nucleus.The article by Craig L. Peterson and Marc-André Laniel is otherwise boringly titled “Histones and histone modifications,” but after this appetizing start, goes into detail about how the tangled mess of alphabetized pasta is exquisitely controlled, folded, unfolded and copied continuously inside the cell, with the help of numerous protein and RNA parts. Of special importance are the histone proteins that comprise chromatin. Scientists have been discovering for several years now that these histones have “tails” of amino acids that can be altered through numerous ways. These alterations, called “post-translational modifications,” seem to influence the DNA wrapped around them in many important ways. They signal genes to activate for transcription, places needing DNA repair, places to start or repress DNA elongation or replication, where to silence telomeres, places to deposit more chromatin, and more. A table in the article lists 95 histone modifications and their functions that are known so far. Some are involved in mitosis (cell division), spermatogenesis, X-chromosome inactivation (silencing one of the two X-chromosomes in the female), apoptosis (programmed cell death), DNA “memory” and other important cell processes. Some have said these modifications constitute a “histone code” (see “Cell memory borders on the miraculous,” 11/04/2002 headline). These authors term it differently, but no less amazing: “rather than a histone code there are instead clear patterns of histone marks that can be differentially interpreted by cellular factors, depending on the gene being studied and the cellular context.” Activities like DNA repair or replication are often accompanied by histone modifications, for instance, as if one enzyme leaves its mark on a histone to signal a follow-up function. Complexes of small RNAs and enzymes depend on these markers to know where to go and what to do; the histone tails serve as attachment points for specific enzymes. And if that is were not amazing enough, the interplay of neighboring histone markers, or cross-talk, can have “a profound effect on enzyme activity.” The authors explain, “Thus, in many ways histone tails can be viewed as complex protein-protein interaction surfaces that are regulated by numerous post-translational modifications. Furthermore, it is clear that the overall constellation of proteins bound to each tail plays a primary role in dictating the biological functions of that chromatin domain.” Finally, since some of these histone states can survive cell division, they augment what’s inherited beyond DNA alone. The authors provide no suggestions on how this system might have evolved. On a related subject, three geneticists from Scotland describe, in the same issue of Current Biology,2 how DNA packs itself so tightly and efficiently. There are specialized proteins called condensins that perform this job. They are members of a set of hairpin-shaped enzymes called “structural maintenance of chromosomes” enzymes (SMCs, see 08/07/2002 headline). The authors remind us that “These extraordinary molecules are conserved [i.e., unevolved] from bacteria to humans.” Scientists are beginning to be able to watch condensin do its amazing work in real time (see “DNA folds with molecular velcro,” 06/07/2004 headline). Condensin produces “supercoils” of DNA, one of many steps in packing the delicate DNA strands into a hierarchy of coils that results in a densely-packed chromosome. “It is not entirely clear how the DNA is held in this supercoiled state,” they say, “but several studies suggest that the V-shaped arms of the condensin complex may loop and clamp the DNA in place.” This clamping is “rapid and reversible.” Scientists watching the process in both bacteria and humans are “showing that both vertebrate and bacterial condensins drive DNA compaction in an ATP-dependent fashion with a surprising level of co-operativity that was not fully appreciated.” The condensin molecules work as a team; if not enough condensin is around, nothing happens. These authors point out also that condensin is just one of many enzymes involved in chromosome formation. Think about how remarkable it is that during each cell division, the chromosomes are structured so reliably that they can be labeled and numbered under the microscope. “Our own proteomic analysis,” they claim, “has identified over 350 chromosome-associated proteins, so there is clearly more work to be done.” There is no mention of evolution in this article, either.1Peterson and Laniel, “Histones and Histone Modifications,” Current Biology, Volume 14, Issue 14, 27 July 2004, Pages R546-R551, doi:10.1016/j.cub.2004.07.007.2Porter, Khoudoli and Swedlow, “Chromosome Condensation: DNA Compaction in Real Time,” Current Biology, Volume 14, Issue 14, 27 July 2004, Pages R554-R556, doi:10.1016/j.cub.2004.07.009.The views we are getting of a cell since the invention of the microscope can be likened to those from a UFO descending from earth orbit to ground level. From orbit, a city like Boston seems to have a lot of structure and organization. As we descend into this alien world, more and more organization becomes apparent, till from airline height, we see complex transportation arteries and machinery apparently all coordinated and purposeful. From helicopter height, individual workers begin to come into focus. We are now approaching ground level, and able to watch factory workers and figure out what it is they are doing. Just imagine what Leeuwenhoek would think, considering he only got the orbital view. It’s not getting any easier for the Darwin Party. If the mental picture of 10,000 miles of spaghetti in a basketball didn’t grab you, considering it is efficiently packaged with each inch of pasta accessible and reproducible, then maybe you just hate Italian food or sports and need a more suitable analogy. Breathes there a man with soul so dead who never to himself hath said, This is my own, my Creator’s hand? Yes, sadly, there is; read next headline.(Visited 309 times, 1 visits today)FacebookTwitterPinterestSave分享0
JP LandmanIn conversations, the same sentiment is repeated over and over, whether around the supper or breakfast table or when answering an opinion poll: South Africa is in decline. Eskom, xenophobia, crime, the poor economy, political uncertainty … we are going downhill fast. Many prefer to leave the country. Those in the know talk of a sixth wave of emigration. The first happened in 1948. The fifth wave occurred just before and after 1993.The mood is not about to lift miraculously either, it seems.Political uncertainty will remain for a year or more. Elections for a new dispensation are still months away. Afterwards, the newly elected still have to find their feet. To make matters worse, some of those elected may be found wanting.While political divide and confusion reign supreme, the world economy, like the local one, is slowing down.Can South Africa escape this sticky, despondent situation?The country experienced a major change in circumstances following 1994, leapfrogging from a traditional society to a modern one. Seen in context, this change is part of a much bigger picture, a much longer continuum.It started off slow enough. One hundred and fifty years after Jan van Riebeeck first set foot on South African soil “…the (Cape) Colony contained one town worthy of the name and five or six little villages,” writes CW de Kiewit in his classic 1941 work, A History of South Africa. Using the dry language of his economic-historical perspective, he paints a picture of the Cape becoming lame because of “deficieny in consumption, activity and animation” and how the Cape “built … its capital slowly”.South Africa really only emerged as a modern society with the discovery and mining of diamonds in the 1860s, and gold in the 1886s. And following this, the institutions which came about as a result of mining became the bedrock for modern South Africa. By comparison, Harvard University was established 200 years before South Africa got its first university college, and 16 years before van Riebeeck arrived in the Cape – a sobering thought.Modernisation was further stunted with the exclusion of black people from the process of participation. From the time that Cecil Rhodes passed the Glen Grey Act in 1894, it took exactly 100 years for South Africa to become democratic.Martin Meredith quotes Rhodes in his address to the Cape parliament, where he motivated the act as follows: “It must be brought home to them [black people] that in future nine-tenths of them will have to spend their lives in manual labour…”The country’s slow start and the economic exclusion of the majority have brought us to today. Our generation are left with three tasks: to establish a democracy which includes everyone; to build a modern economy whose growth exceeds that of the population; and address the enormous disparities by eroding the social imbalances which still exists among the previously disadvantaged.The two aforementioned tasks have largely been achieved. Despite showing only 3% economic growth this year, it remains higher than the population growth and is still more than the 1% with which we had to satisfy ourselves for almost two decades. But, other critical issues still need to be addressed – the attack on the judicial system should be averted, and economic growth needs to remain a political priority. Then, social development can follow.Seen in this light, the current pessimism is a good thing. It may be the cause of much disgruntlement, but it also creates the opportunity for creativity and energy.We hear of groups of citizens getting together, as was the case during the apartheid years, to discuss the state of affairs and the direction the country is going. Growing concern and general discontent with political parties are increasingly voiced.That’s how we will escape the sticky situation. We need to loose our naivety. Change will not come easy. To be truly modern is not just about suffrage, about easy reconciliations. What we have to behold is the enormous challenge of social development. And decide from what moral foundation we want to approach the current situation – and then live these values.Just maybe, a new generation is born out of this situation – a generation intent on making South Africa truly modern. A generation no longer crying over spilt milk.JP Landman is a self-employed political and trend analyst. He consults to SA largest private wealth business, BoE Private Clients, and works with several SA corporates on future scenario trends. His focus areas are trends in politics, economics and social capital.Among some of the unique research projects his consultancy has undertaken was the role of public institutions in battling corruption (quoted by the UN in a report on corruption), the interplay of demographics and economic growth, and an overview of trends around poverty alleviation in SA. Whilst working as an analyst on the JSE in the 1990s he was voted the top analyst in political trends.He is also a popular speaker who has addressed diverse audiences locally and internationally and enjoys consistently good ratings.He has a BA and LLB degrees from Stellenbosch (1978), studied Economics and Development Economics at Unisa (1979 and 1980) and later at Harvard (1998 and 2005), and obtained an MPhil in Future Studies (cum laude) from Stellenbosch (2003).
New Delhi, Apr 6 (PTI) Sunrisers Hyderabad has signed up India largest and most awarded Radio network, Red FM as their principal sponsor for the fourth year in a row. As part of the partnership, the Sunrisers Hyderabad team will sport the Red FM logo on the front of the jerseys. Additionally, Red FM will bring its saliency to the field as well as on-ground activation with the Sunrisers Hyderabad team. Captained by India opener Shikhar Dhawan, Sunrisers Hyderabad has added some exciting talent for this season, including explosive Indian all-rounder Yuvraj Singh, New Zealand captain Kane Williamson, pacer Ashish Nehra and England captain Eoin Morgan. Sunrisers Hyderabad has star players like David Warner, Naman Ojha and Bhuvneshwar Kumar who have been part of the team. Speaking on the occasion Nisha Narayanan, Chief Operating Officer, Red FM said: “Red FM stands for a fun, spirited and exiting attitude that reflects in our programming and in our people. Its no surprise then that we are happy to be partnering Sunrisers Hyderabad for the fourth year in a row. “Sunrisers Hyderabad has the most impressive line-up of cricketing stars. The association looks promising and we hope to deliver to our listeners an experience to remember. We have planned extensive on-ground consumer engagement initiatives to leverage the assoction. Wishing SRH a good season ahead!” Sunrisers Hyderabad CEO K Shanmugan added: “Sunrisers Hyderabad has had an exciting journey in the Indian Premier League and as always, we are very happy to continue and strengthen our relationship with the Red FM team. In the past, we have done some fabulous promotions with Red FM that has helped in promoting our team and its players and has helped us in building strong equity with SRH supporters. We are looking forward to this association this year too.” As part of the partnership, Red FM will run contests online as well as on-air during the IPL season and winners of these competitions will be rewarded with official merchandise of Sunrisers Hyderabad and autographed memorabilia. Apart from this, Red FM being the official radio partner, will also run interesting contests for match tickets at the teams home turf at Rajiv Gandhi International Stadium in Hyderabad. The partnership will also see key team players on-air on Red FM and engage with listeners across cities. Listeners also stand an amazing opportunity to connect and meet their favourite Sunrisers Hyderabad players. On the digital front, Red FM will release behind the scenes video content on its digital platforms. PTI SSC SSCadvertisement
India head coach Ravi Shastri has now joined the list of wishes that have been showered on the Virat Kohli and Anushka Sharma ever since they declared their marriage to the world.On December 11, Kohli and Anushka tied the knot in Tuscany, Italy, which was attended by only close friends and family.Shastri took to Twitter to wish the “young man” (Kohli) and wished the couple “all the happiness and a blissful married life.”Many congratulations young man. God bless you two with all the happiness and a blissful married life. Happiness – @imVkohli @AnushkaSharma pic.twitter.com/p2EAH44UBv- Ravi Shastri (@RaviShastriOfc) December 16, 2017On the other hand, Kohli is surely enjoying his rare time off from cricketing duties.After having the beautiful wedding in Italy, Kohli and Anushka were last seen enjoying an exotic honeymoon.Four days after their wedding, Anushka shared their honeymoon picture on Instagram that sent the social media into frenzy.Now, fresh pictures have come out on social media where the couple fondly called ‘Virushka’ are seen having a gala time with friends and family.Photo Credit: Instagram The photos exhibit the friendly yet loving equation between the Indian captain and the Bollywood star.Photo Credit: Instagram The couple will host a reception in Delhi on December 21 after which they will throw another reception party in Mumbai.Kohli, who finished 2017 with 2818 international runs and 11 hundreds in international cricket, had been rested for India’s limited-overs matches against Sri Lanka.advertisementKohli has been in sensational form since the beginning of 2016 when he smashed two hundreds in the five-match ODI series against Australia before turning his focus to T20 cricket, breaking a plethora of records. After scoring hundreds of runs in the international format, Kohli amassed 973 runs including four hundreds in 2016 IPL.He also became the only batsman to hit double hundreds in four successive Test series during the one-off match against Bangladesh earlier this year. After a lean patch in Test cricket against Australia, Kohli hammered 610 rus in the three-Test series against Sri Lanka at home.Currently, Kohli is the leading run-scorer in ODIs this year and is ranked No.1 in ODIs and T20 Internationals. He is also ranked number 2 in Test cricket.’In the course of a dominant year for India, Kohli also went past Ricky Ponting and is now second in the list of century scorers in ODIs. The Delhi dasher has 32 hundreds and many experts feel he would be able to get close to Sachin Tendulkar’s 49 tons in the format.Kohli now has the most double centuries as a Test captain (6). He joined Sachin Tendulkar and Virender Sehwag at the top of the list for most double centuries by an Indian in Test cricket.Kohli became the only Indian to aggregate over 600 runs in a single Test series for the third time. Sunil Gavaskar and Rahul Dravid had achieved the feat twice.Kohli broke a plethora of records during the Test series against Sri Lanka and became only the second Indian batsman after Vinod Kambli to score two consecutive double hundreds.Under Kohli, India have won nine successive Test series but their major challenge will be in South Africa where the first Test between the two teams gets underway in Cape Town on January 5.
Liverpool attacker Shaqiri admits ‘nice’ seeing Tottenham loseby Freddie Taylor10 months agoSend to a friendShare the loveLiverpool attacker Xherdan Shaqiri says it was nice to see Tottenham lose on the weekend.Spurs were defeated 3-1 by Wolves on Saturday to leave them nine points behind Liverpool, who thrashed Arsenal.”Obviously [it boosted us],” the 27-year-old told Standard Sport when asked about Tottenham’s result on Saturday.”I think everybody when they see some teams struggle, who are behind you and coming after you, it’s nice to see obviously.”But, in the end, we look to ourselves and win our games.” About the authorFreddie TaylorShare the loveHave your say
Joe Young DunkJoe Young saw action in 41 games as a rookie for the Indiana Pacers last season, and the former Oregon star is playing with the franchise’s team in the Orlando Summer League this week. In a game today against the Orlando Magic, Young threw down a crazy one-handed dunk on a fast break before landing awkwardly. He was okay, and the dunk was phenomenal. Pacers 2015 2nd rounder Joe Young gets a nasty posterhttps://t.co/nbFf6W8onT— Bleacher Report (@BleacherReport) July 2, 2016If Young keeps doing that, he’ll push for more playing time on a revamped Pacers roster in 2016-17.
Kolkata: A trolley booth has been set up on the premises of the NRS Medical College and Hospital to act tough against the touts, who demand money for providing trolleys and wheel chairs to patients, and to reduce the confusion of the patients and their family members over the process of hiring trolleys at the hospital.Apart from trolleys, many wheel chairs have being kept at the booth that has come up just opposite to the emergency building of the NRS Medical College and Hospital. Also Read – Bengal family worships Muslim girl as Goddess Durga in Kumari PujaPatients and their family members or any other person associated with the hospital who needs a trolley will have to go to the booth. They have to provide some necessary information at the booth before hiring a trolley or a wheel chair. The move to ease the process of hiring trolleys will help to tackle the problems of touts, who have allegedly been operating from the hospital and demand money from the patients and their family members for trolleys. There were allegations that the patients often face problems due to the tout menace in the hospital. Also Read – Bengal civic volunteer dies in road mishap on national highwayThe trolley booth will remain open for 24 hours. The patients face problems to get a trolley at the emergency ward. Now, the family of the patient can get the trolleys from the booth after providing the name of the patient and his mobile number. Security personnel will be deployed at the trolley booth. In the initial level around 25 trolleys and 4 wheel chairs are available in the booth. The number would be increased gradually, a senior official of the NRS Medical College and Hospital said. The hospital staff members used to face problems as the patients and their family members did not keep the trolleys in designated places after using them. As a result, the staff members of the hospital had trouble to find the trolleys left by the patients at various wards. The patients often alleged that the wheel chairs were not available when there was a requirement and as a result people having serious health condition had to suffer. It was alleged that the staff members of the NRS Medical College and Hospital ask for identity proofs such as Aadhaar card, voter identity card, driving licence while hiring a trolley. The system was seldom found in other government hospitals. The main purpose of introducing the system is to ensure that the family members of the patients return the trolleys in the designated places after use. It may be mentioned here that the group D staffers of the hospital are supposed to fetch the trolleys from various wards but as there is a crisis of group D staffers in various hospitals the hospital authorities are facing problems.
Visakhapatnam: Delhi Capitals opener Prithvi Shaw heaped praises on teammate Rishab Pant, calling him the best finisher among youngsters after the 21-year-old helped Delhi Capitals beat Sunrisers Hyderabad by two wickets in a nerve-wracking IPL Eliminator here. Chasing a target of 163, Delhi Capitals, who had lost the way after a blazing start, were brought to cusp of victory by Pant, who smashed 49 off 21 balls with five sixes even as West Indies’ Keemo Paul finished it off in the penultimate ball of the innings with a boundary off Khaleel Ahmed on Wednesday night. Also Read – We will push hard for Kabaddi”s inclusion in 2024 Olympics: Rijiju”In these T20 games, there’s a lot of pressure. I was praying that we win. Pant did a brilliant job. I have said that he is the best finisher among the young players. He always opens up the game for us. He has been doing very well. Unfortunately, he could not finish it for us, but Keemo did well in the end,” Shaw said at the post match press conference. He also pointed out that Amit Mishra’s single run was an important one. The 19-year-old said it was important for him to get back into form after a few bad games. Shaw top-scored with 56 off 38 balls on a “sticky wicket” to give Delhi a great start. “First six overs are important because if you put runs on board, it will take the pressure off the other batsmen. It was a bit difficult to pull the ball. Since their bowlers were bowling cutters on a sticky wicket, it was not pulling.”
The weeks coming out of the All-Star break typically tell us a lot about the teams we still have lingering questions about. This season, some of those — like the Cleveland Cavaliers — saw so much change so recently that we won’t be able to answer those questions anytime soon. But for everyone else, we’ve seen enough games to know what to look out for over the remaining quarter (or so) of the regular season. Here’s a quick survey of the contenders as they come out of the All-Star break.Toronto RaptorsIt’s time to start talking ourselves into the Raptors, and this season that means talking ourselves into DeMar DeRozan. The standard palette of advanced statistics doesn’t do much to show how this year’s vintage of DeRozan differs from previous ones. His true shooting is about the same as it has been for a few seasons; his usage rate is the same as it’s ever been; his assists are up, but not dramatically so; and even his celebrated improvement from downtown has him shooting the 3-pointer about a percentage point worse than he did two seasons ago, albeit on twice as many attempts. Drill a little deeper, and his points created on drives and the pick-and-roll are steady compared to last season as well, according to Second Spectrum.But if you watch a few Raptors games, the difference slaps you in the head. Yes, he’s working with a bit more space now that he’s shooting more threes and hitting them at a baseline respectable rate. But it’s how DeRozan is handling the added defensive pressure, recognizing the double-team quickly and passing to shooters, that sets this season apart from his others. He is creating 100 points per 100 chances when he drives and kicks to a shooter, according to Second Spectrum. Last season that was 87 points per 100 chances. How different you imagine the Raptors’ chances are this season compared to the past more or less depends on how much you believe DeRozan’s game has grown. It’s a case where improvements picked up by the eye test are borne out by some of the more granular stats, but not in the aggregate. Sometimes that’s a signal to keep an eye out for big overall changes despite relatively few changes to the components; other times, it’s just noise.Minnesota TimberwolvesJimmy Butler played zero minutes in Sunday’s All-Star game, and he didn’t practice on Saturday. NBC Sports Chicago’s Vincent Goodwill reported that a person close to Butler said, “He’s OK, just tired.” This was meant to be encouraging, signaling that Butler isn’t injured. But for one of Tom Thibodeau’s players, it may be something more worrying.Butler is logging 37.3 minutes per game this season, and has averaged 39 minutes since missing four games to injury at the end of January. He covers the league’s third-most miles per game, and does so while creating the sixth-highest “load” — Second Spectrum’s adjusted metric for describing the physical stress of accelerating and decelerating. Butler’s usage and efficiency have held steady since December, when he began to take a larger role and play more to his previous All-NBA form. But if fatigue is enough of a concern to make the Wolves’ star sit out an exhibition game, then, as the season winds down, Butler’s fatigue should be as big a concern to the Timberwolves as the team’s leaden defense. A lot of things go into a solid NBA defense, but effort and energy are high up on the list. And if the Wolves’ best wing defender is low on either, it doesn’t bode well for the team fixing what isn’t working, or maintaining what is.Boston CelticsAfter a great start to the season, the Celtics are reeling. The team has lost nine of its last 15 games and is second in the East, two games back of Toronto. It’s the defense that’s sinking them. With Marcus Smart and Shane Larkin out the past few weeks, Boston’s D has looked downright average. The team’s defensive rating is 107.7 over those last 15 games and 108.7 in the 11 without Smart. Before that 15-game stretch, it had been 102.7. The Celtics still lead the league in defensive efficiency for the season, but the defense without Smart would tie it with the Lakers for 14th. An average defense won’t be enough for Boston, which is also average on the offensive end and has not improved since Smart went down.Houston RocketsEarly on in the season, as the Rockets were adapting to playing with Chris Paul and James Harden — two All-NBA-level guards — in the backcourt, it was popular to observe that the team was better when one was on the court and the other sat. The team was good with both, but exceptional with just one. It would eventually pay off to have one such configuration on the court at all times, the thinking went, even if the main lineup wasn’t as potent. But that’s no longer really the case.When Harden and Paul share the floor, the Rockets score 123.6 points per 100 possessions and give up 110.7, according to NBA WOWY. That difference of 12.9 points per 100 possessions splits the difference between the Harden-only lineups (+8.7 points per 100 possessions) and the Paul-only ones (+16.5). Just as important as how the lineups fall in relationship to each other is how they compare with the rest of the league. The Paul/Harden lineup would be the best in the league and is about in line with the Warriors’ lineups that feature Steph Curry, Klay Thompson, Draymond Green and Kevin Durant (+12.2). The Rockets may improve further down the stretch, but they’ve already established their star lineup as as asset all on its own, not simply a means to individually successful lineups for Harden and Paul.San Antonio SpursThe Spurs’ season has been held hostage to Kawhi Leonard’s mysterious, lingering quad ailment. On Wednesday, San Antonio coach Gregg Popovich said he would be surprised if Leonard returns this season. Leonard has played in a total of nine games this season, the last in mid-January. Still, the Spurs sit in third place in the West and stand a good chance of winning 50 games for the 19th consecutive season. But for that to happen, the team will need to settle in under 21-year-old point guard Dejounte Murray.Murray took over for Tony Parker as starter in late January, and the Spurs have lost seven of 12 games since the change. This is a problem because seven teams are within five games of the Spurs, including the 10th-seed Utah Jazz, who have been on fire since the return of Rudy Gobert. But while the Spurs have dropped some games, Murray has improved rapidly. Before breaking into the starting lineup, Murray was creating just 78 points per 100 chances as a pick-and-roll ballhandler, according to data from Second Spectrum. That’s one of the worst figures in the league for a player tasked with doing it with any frequency. Since taking over, Murray has created 102 points per 100 chances. It’s not as though Murray is suddenly attacking his man like Russell Westbrook does, but he’s moving the ball through the Spurs’ system well and manipulating defenders into positions to help teammates. If that form continues, the Spurs should be able to right the ship — or make it as right as it can be without Leonard.Golden State WarriorsOut to lunch. Back in June. Check out our latest NBA predictions.