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DNA tape recorder stores a cell’s memories

first_imgIf cells could talk, they’d have quite a story to tell: Their life history would include what molecules they’d seen passing by, which signals they’d sent to neighbors, and how they’d grown and changed. Researchers haven’t quite given cells a voice, but they have now furnished them with a memory of sorts—one that’s designed to record bits of their life history over the span of several weeks. The new method uses strands of DNA to store the data in a way that scientists can then read. Eventually, it could turn cells into environmental sensors, enabling them to report on their exposure to particular chemicals, among other applications.“They’ve done a really exceptional job turning DNA into readable, writable memory inside living cells,” says Ahmad Khalil, a biomedical engineer at Boston University who was not involved in the new work. “I think it’s a very cool new direction for synthetic biology to take.”In the past, researchers have turned cells into simple sensors by switching on or off the production of proteins in response to a stimulus. But each switch could record only one simple piece of information—whether the cell had been exposed to the stimulus—not the duration or magnitude of this exposure. And if the cell died, the information—encoded in a protein—would be lost.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)“We wanted a system that would be easier to scale up to collect more than one piece of information,” says synthetic biologist Timothy Lu of the Massachusetts Institute of Technology in Cambridge. “So we started out, as engineers, thinking about what an ideal memory system would look like.”Lu’s team settled on a biological program that rewrites a living cell’s DNA when the cell senses a signal—from a flash of light to the presence of a chemical. Once the DNA is altered, the information remains embedded in the genetic material even if the cell dies. By sequencing the genes of a population of cells that all contain the program, researchers can determine the magnitude and duration of the signal: The more cells have the genetic mutation, the stronger or longer the signal was.The approach, dubbed Synthetic Cellular Recorders Integrating Biological Events (SCRIBE), relies on retrons—which make up a genetic system found naturally in some bacteria that produces single-stranded DNA that the bacteria normally use to alter their host. Lu’s team started with bacterial cells and inserted a retron that would be turned on—producing the unique DNA—only in response to a specific stimulus like a chemical. While the cell is in the process of copying its genetic material, the new DNA would then replace a nearly identical existing gene segment in the cell, changing it slightly.  Lu tested SCRIBE on cells that he engineered to sense light, as well as others that responded to a common biological reagent. In one instance, he made the memory especially easy to read by engineering the cells to mutate an antibiotic resistance gene in response to light. When cells were then grown in the presence of the antibiotic, the researchers could immediately see which cells contained the new gene. The results were confirmed by sequencing the bacteria’s genomes. But SCRIBE, described online today in Science, could be designed to sense other stimuli and cause any desired genetic mutation in return.“There are a bunch of potential applications of this system,” Lu says. “One is being able to do long-term recording of a cell’s environment.” For example, he says, living cells could be left in an area of water for a week, then collected. Sequencing the DNA from the cells could then reveal whether the cells had been exposed to certain bacteria or toxins in the water. SCRIBE could also be a boon to basic researchers, Lu adds. “During development, as you go from a single cell to a multicellular organism, each cell encounters different cues,” he says. SCRIBE could let researchers record what each cell encountered to shape its fate.“What’s neat about this strategy is that you have a lot more diversity and flexibility than other methods to give cells memory,” Khalil says. Because scientists can choose the stimulus—or multiple different stimuli—that they want the cell to record, as well as what gene change they want to use as a marker, the possibilities for applications are wide, he says.last_img read more

India’s Regulators Seek to Rein In Internet Giants

first_imgIn India, U.S. companies dominate the internet. Facebook’s WhatsApp is the most popular app on phones. Virtually every smartphone runs on Google’s Android system. YouTube is the favorite video platform and Amazon is the No. 2 online retailer.For some Indian political leaders, it is as if their nation — which was ruled by Britain for a century until 1947 — is being conquered by colonial powers all over again.And they are determined to stop it.“As a country, we have to all grow up and say that, you know, enough of this,” Vinit Goenka, a railways official who works on technology policy for India’s governing Bharatiya Janata Party, said at a conference last week.In recent months, regulators and ministers across India’s government have declared their intention to impose tough new rules on the technology industry. Collectively, the regulations would end the free rein that U.S. tech giants have long enjoyed in this country of 1.3 billion people, which is the world’s fastest-growing market for new internet users.The proposals include European-style limits on what big internet companies can do with users’ personal data, a requirement that tech firms store certain sensitive data about Indians only within the country, and restrictions on the ability of foreign-owned e-commerce companies to undercut local businesses on price.The policy changes unfolding in India would be the latest to crimp the power — and profits — of U.S. tech companies, and they may well contribute to the fracturing of the global internet.In May, Europe put into effect a sweeping new privacy law that gives Europeans more control over what information is being collected on them. In the United States, California just passed a privacy law that gives state residents more protections than Americans at large.As India sets the new rules of the game, it is seeking inspiration from China. Although India does not want to go as far as China, which has cut off its internet from the global one, officials admire Beijing’s tight control over citizens’ data and how it has nurtured homegrown internet giants like Alibaba and Baidu by limiting foreign competition. At the same time, regulators do not want to push out the U.S. internet services that hundreds of millions of Indians depend on.For Google, Facebook, Amazon and others, India’s moves would curb a lucrative business avenue — especially after so many of them were blocked in China. India had become the companies’ next frontier for growth.Salman Waris, an expert in international technology law at TechLegis in New Delhi, said India was trying to establish strong data protections for its citizens, as Europe did, while giving the government the right to obtain private information as it sees fit, much as China does. Foreign tech companies will have little choice but to go along.“Everyone is going to fall in line and do what is necessary,” Waris said. “These companies have to do it in China and Europe, and they will do it here.”India’s new policies are still a work in progress, with competing government agencies jousting with foreign and domestic lobbyists and policy advocates to shape them.But new restrictions are definitely coming, said officials and industry executives involved in the process. The country’s Supreme Court declared last summer that Indians have a fundamental right to privacy and pushed parliament to pass a data privacy law. Prime Minister Narendra Modi and his BJP party have embraced an India-first economic nationalism to address weak job growth before elections next year. Law enforcement authorities are also demanding more legal tools to extract private customer data from WhatsApp, Facebook and financial firms.“We don’t want to build walls, but at the same time, we explicitly recognize and appreciate that data is a strategic asset,” said Aruna Sundararajan, the nation’s secretary of telecommunications, who has been deeply involved in the policy discussions. “There is a strong feeling in many quarters that the reason that India has not been able to develop a Tencent or Baidu or Alibaba is because we have not been nuanced in our policies.”The Indian government, which sees data as vital to a whole new generation of technologies such as artificial intelligence, appears particularly determined to reel in Facebook and its WhatsApp messaging service.Officials were furious after the Cambridge Analytica scandal this year revealed that Facebook had shared private information on 87 million users, including 560,000 Indians, with a political consulting firm that had sought to influence Indian elections.More recently, the Ministry of Electronics and Information Technology has demanded that WhatsApp create a way to track and stop mass messages, such as a series of false items about child kidnappers that led to the murder of two dozen innocent people by angry mobs.WhatsApp has refused, saying that building such technology would break the encryption that keeps messages private. The government, for its part, is holding up a new Indian payments service from WhatsApp until it complies with local laws, including a new rule that requires financial data to be stored only in India.More broadly, the Indian government says it wants to ensure that Indian and foreign companies have to follow the same rules on taxes, data storage, security, pricing and cooperation with law enforcement.For example, Indian travel agencies complain that current tax laws allow foreign services such as Booking.com to avoid collecting hotel taxes, which can run as high as 28 percent of the room price. The disparity, they say, gives foreign firms a price advantage.“It’s not about protectionism. It’s about saying if 10 laws apply to me, the 10 laws should also apply to someone else operating in India,” said Rameesh Kailasam, chief executive of IndiaTech.org, a newly formed lobbying group that represents local investors and startups, including MakeMyTrip and the ride-hailing company Ola.In a statement, Booking.com said it made a “full effort” to comply with Indian tax laws.The big U.S. technology companies are trying to fend off or dilute the regulations behind closed doors. Many consider the topic so sensitive that they refused to discuss it on the record.In private, the companies say that the proposals would raise their costs, dampen their ability to use Indian data to improve services and dissuade investments like Walmart’s recent $16 billion deal to buy control of Flipkart, the country’s leading online retailer.They also warned that India has fewer legal protections than the United States against government searches and data requests, so private data stored in the country could more easily end up in the hands of the police.The issue may become a topic in trade and economic discussions between the United States and Indian governments scheduled for the fall.Mukesh Aghi, the chief executive of the U.S.-India Strategic Partnership Forum, a policy group whose board includes top executives at Cisco, Adobe, and Mastercard, said India risked hurting its own economy by imposing stringent rules on foreign tech companies. Forcing data to be stored in India, for example, could prompt similar rules from the United States, which would hurt India’s big outsourcing companies.India also needs multinational companies to build its tech economy, he said.“It requires deep pockets. It requires world-class technologies. It requires a global supply chain,” said Aghi. “These companies are creating jobs.”Ajay Sawhney, the information technology secretary, who is helping to draft the regulations, said the government was keeping an open mind as it developed the final rules.“Our framework will be fair to all stakeholders,” he said. “We deeply appreciate the value that the tech companies and their platforms bring to our country.”© New York Times 2018 Related Itemslast_img read more