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Class Supplement, Nature Podcast Digest 2012/04/12

2012年5月27日

Recommended tasks with this material: Listen to the original podcast, the URL provided below. Summarize the points in English first aurally and then write the summary down. Compare it with the Japanese summary provided before each section in this supplement.

☆使い方: 1) プリント1ページ上のURLで音源をタウンロードして聞く。(スクリプトもダウンロード可能)2) プリントの英文で内容確認。3) 要約を言って書いてみる。4) プリントの和文要約を見て確認。

The audio file of this podcast:http://www.nature.com/nature/podcast/archive.html

The original script of this podcast: http://www.nature.com/nature/podcast/v484/n7393/nature-2012-04-12.html

動物の病原体となる菌がグローバル化と共に世界中に広がっている。通常の病原体の場合、宿主(菌が寄生する生物)の数が減ると病原体も消失し、宿主の種は復活する。しかし菌類の場合、多種多様の宿主に付いているため、消失することはなく、弱い宿主は絶滅する。植物と違い、除菌はうまくゆかない。菌の移動阻止が最も有効な対策。全てを見積もることは不可能だが、菌によって失われる生態系が果たしている役割をお金に換算すると相当な額になることは確か。

Matthew C. Fisher: Well, here we have a large box full of newts which are just coming back into the water after being hibernated over winter and what’s common with all of these newts here is that they’re infected by a very highly virulent lineage of the fungus, Batrachochytrium dendrobatidis which has been spreading like wild fire around the world, causing a number of species extinctions that we’re seeing. The Mallorcan midwife toads on the other hand have got a very similar lineage of the fungus, but it doesn’t kill, at least not in the level that we see with the strain that’s infecting these newts. So it seems that not only we’re moving these very highly aggressive forms of fungi around, but we’re also moving other less aggressive forms around and what really kind of comes together is that we’re actually just doing a lot of moving around with absolutely everything. There’s just this whole global rearrangement going on, not only in fungi but also in bacteria, viruses, vertebrates, pretty much anything you care to mention.

Geoff Marsh: So would you say that all these recent outbreaks in the wild animal populations are down to human activity?

Matthew C. Fisher: Yes, all of these disease emergences are symptomatic, essentially of globalization.

Geoff Marsh: And so your research in this lab, working on this one particular pathogen, fits into a wider global picture of the impacts, fungal pathogens are having on wild animal species.

Matthew C. Fisher: Yes, it does. So, we now know there are probably more than three and half million species of fungi out there. Only a handful of which are known to cause serious disease in vertebrates, but importantly that number is increasing year on year. So scientists at the United States are finding that this new species of fungus Geomyces is causing the destruction of the North American bats and they’re seeing fungi that were previously thought to be non-virulent causing decline in coral in the Caribbean and it goes on and on. So, yes, there’s a lot of fungal biodiversity out there, and we’re finding out that more and more that has this rather nasty characteristic.

Matthew C. Fisher: Well initially, theory shows that as the host becomes rarer, as pathogens dry, the density is down, then the pathogen itself tends to go extinct before the host does and then the host bounces back and this is the normal density dependent cycle that you see with the host and its pathogen. However, fungi have this set of characteristics that enable them to wade these limiting mechanisms, so particularly what fungi are very good at doing is persisting in the environment or infecting many, many species that are generally parasites. So that means that when you’ve driven your susceptible species down to very low levels, the chances are that you’re also holding out in another tolerant species that you keep on releasing infected stages into the environment and eventually overwhelm that susceptible species and bang it’s gone.

Matthew C. Fisher: Well, as you rightly point out, there’s a huge industry that goes into protecting crops against fungal pathogens, but you just can’t do that, in natural wild life populations. It really is an incredibly difficult problem. Certainly on the island of Mallorcan where we have these beautiful Mallorcan midwife toad tadpoles, we’ve actually gone there and we’ve caught every animal in the valley and treated it with an antifungal drug and we’ve kept it in a bio-secure facility until we hope that the fungus has disappeared from the environment and then we put them back. So, essentially, we’ve tried this environmental mitigation and it really just hasn’t worked. So, yes, we have to be very creative in solutions that we use against these pathogens in the future, but essentially, the bottom line is just don’t introduce them in the first place.

Geoff Marsh: I mean, it’s very obvious to put a value on crop species that might be being infected by fungal pathogens, how do you put a value on these wild populations of frogs and newts etcetera?

Matthew C. Fisher: Well, this is of course a very difficult problem. We don’t really understand the wider value of the ecosystem services that these species produce. Some scientists in America have attempted to do this and they’ve costed out the services that the bats do every year by eating pests and this turns out to be a very big number, three and a half billion dollars per year, perhaps more, and similarly, you know, these frogs are going to be providing services which are essential to us; however, we’ve never actually put a number to this and this is really important these days because to actually recognize the value of these species and the loss owing to these new diseases that accrue we really need to understand the actual financial cost that they provide to us.

量子コンピューターや量子暗号技術(見る=測定すると変化するので見ることができない量子状態(同時に0と1の両方である状態)を利用して盗聴を防ぐシステム)用に開発されているのが、単一光子を使った量子通信ネットワーク。【(送信元)原子 → 光子 → 原子(受信先)】この技術を使うとネットワーク内の2点で量子もつれ(離れた場所にある粒子が同時に同じふるまいをする現象)が起こせる。すなわち、量子通信では情報を乗せたある量子状態がほぼ同時に別の場所で再現できる。ただし、送信には従来の光ファイバー回線が必要なので送信速度が光速を超えることはない。

Stephan Ritter: There are many applications for transmitting the quantum state, and one is that with a quantum computer, you’d build on these strange quantum states and if you want to distribute the quantum computing, say, like one does with cloud computing all the time, then we might want to exchange quantum states and exchanging classical states is just not enough. And another application is quantum cryptography, so quantum cryptography, also building on these super position states, entanglement allows you to exchange the super key with if you do everything correctly, absolute security and to do so you also need to exchange quantum space, but you can’t copy quantum state and also if you measure it, you alter the quantum state. So say, you have a quantum state and you don’t what it is and you want to send it to me, then you don’t have the opportunity of measuring it and sending it to me by a classical channel, you have to send it by some means like we do.

Geoff Brumfiel: You can’t even read the information before you send it. This is just started like the weirdest network ever to me.

Stephan Ritter: Well, I mean, if you prepare quantum state and you know that state, then you could of course just called me and tell me well, I have this quantum state, try to prepare it at your place and then I have the same quantum state, but sometimes, say some person in the future would do a quantum computation and their quantum state becomes out of a result, then if you measure that you won’t get the full quantum state because if you said if he has these super positions being zero and one, at the same time, then the measurement process will project this state, onto either zero or one and thereby destroy the quantum state that you initially had. So then measuring and sending is not an alternative in the quantum world.

Geoff Brumfiel: So, basically this is a network that allows you to send multiple possible answers that you don’t know before you send them.

Stephan Ritter: That’s correct, yes.

Geoff Brumfiel: And so let’s talk a little about how you actually did it because it wasn’t even clear that this could be done.

Stephan Ritter: That’s right. So, when we talk about the quantum network, what we mean is that you have network nodes and between those, you transmit the information. So, as a transmitter, single photons are ideally suited because they fly at the speed of light and you make them interact rather weakly with the environment so they’re great for transmitting information from A to B, but then they are not stationary and so they’re not suitable as network nodes. And so we take these network nodes or single atoms and now the task is to transfer quantum information from the stationary nodes or from the single atom onto a single photon then transmit it via your quantum channel which typically is an optical fiber to the other network node and they have to convert it from the photon onto the other single atom at this second node and then have it stored there.

Geoff Brumfiel: You can do some really crazy things with this network, you’re able to tweak one part of the network to actually manipulate or physically separate it, part of it instantly, is that right?

Stephan Ritter: That’s right. So, what we’ve done in the second experiment is that we entangled the two network nodes so what we do is we produce a single photon from one of the network nodes in such a way that the polarization of this photon, this entangled with the atom or the internal atomic state. And then we send again the photon over and store it coherently in the second network node and we achieve this in such a way that the two single atoms, even they’ve never seen each other, they’re entangled.

Geoff Brumfiel: And it would work instantly between.

Stephan Ritter: That’s correct.

Geoff Brumfiel: That’s a really weird thing.

Stephan Ritter: Yes.

Geoff Brumfiel: I assume this network can communicate faster than the speed of light.

Stephan Ritter: No, no it can’t because you always need a classical communication channel.

南伊地方のタフという近在は全然タフではない。高温下で耐圧性が劇的に低下する。これはタフがゼオライトという鉱物を含むため。

Corie Lok: Take a trip through southern Italy, near Naples, and you’ll come across many buildings made of the yellow volcanic rock called tuff. Tuff is definitely not tough though. It’s known for being a weak building material. At least one type of tuff could pose an even greater hazard in the event of a fire. Researchers subjected three types of tuff used in Italy to high heat and then tested the rock’s strength. They found that the most commonly used rock, called Neapolitan yellow tuff, lost 80% of its compressive strength as temperatures reached a 1000 degrees Celsius. That’s because this Tuff contains zeolite minerals that are sensitive to heat. The researchers suggest that the results be considered in establishing regional fire codes. They also recommend similar tests for Tuff used in other regions. The study was published in the Journal, Geology. Nature 484, 144 (12 April 2012)

リンパ腺を作るための遺伝子が活性化している組織内でのみ光る蛋白質を作るマウスができた。リンパ腺の発達や癌の転移の研究に使える。

Another paper that caught our eyes, looks at the growth of lymphatic vessels in the body. These vessels transport white blood cells and fluids and often sprout at sites of inflammation. They’ve also been linked to the spread of cancerous tumors. So, biologists would love to get a glimpse of these vessels growing inside living animals. Now they can. Researchers have genetically engineered a mouse that produces a luminescent protein only in tissues where a lymphatic gene is turned on. They captured images of lymphatic vessels growing in live mice during embryo development and wound healing. They could even see vessels growing at the edge of melanoma tumors. The authors suggest that lymphatic growth may help cancers spread to distant organs.

教育熱心であるにもかかわらずインドが科学分野で伸び悩んでいる原因は上下関係の厳しい文化。科学で必須の疑問視や反対意見表明はあり得ない。自由に研究発表できる土壌作りが必要。 改善案: (1)研究資金を多数の人に分配する。 (2)エネルギー、水、公衆衛生問題に特化する(融資増) (3)受賞者以外の認知もすすめる。 長期的には、正しいことは損得抜きで支援し、間違いを認める勇気を持つことが大切。

Kerri Smith: India has always treasured education, but it’s having a hard time translating that into world class science. Lack of money isn’t the problem, according to chemist, Gautam Desiraju at the Indian Institute of Science in Bangalore. He thinks it’s a cultural thing. I gave him a call to find out what he meant. Nature 484, 159-160 (12 April 2012)

Gautam Desiraju: Science is based on a systematic questioning and a logical approach. It’s the questioning I’m saying, we’re not able to do because our cultural values systems does not allow us to do this so easily. India is a country where conformity is given a very high priority. Listening to people who you feel are older than you or more powerful than you is very, very important and not sticking out like a sore thumb.

Kerri Smith: And the barriers are not financial necessarily, but there are these psychological barriers.

Gautam Desiraju: I think so and I think these psychological barriers are very, very serious. I call it the feudal colonial mentality. So, the first consequences that we’re not able to question and the second thing is we worship older people. It starts at a very basic level; a postdoctoral person comes back to India from a very good lab abroad and continues to do the same thing. Now if we did that in the UK or the USA or Germany, he would not rise in his job, because innovation is given the maximum points. I’m addressing, I think, a basic sociological issue and therefore knowing I think what policy makers need to do is they have to factor this in into their calculations. Otherwise, say that you’re not in this game of doing international science, but once you say that I want to compete with the others, I want to get my paper into so and so journal, so on and so on, then you have to do it in a way that is compatible with the whole system, not what we’re doing. This is some kind of a mismatch and I really fear this extra money into the system now because I know its just going to be like you know, pouring money down a rat hole.

Gautam Desiraju: I’ve given a number of suggestions. Now the short-term, start providing small funding to a very large number of people, doesn’t matter if many of these projects fail, but there should be feeling of mass participation and then when you do provide big money, these should be of, you know, in critical areas, I’ve mentioned energy, water and public health. So the funding can be very high, the accountability should be high and there should be proper exit options. In other words, if the thing is not working, we should have the guts to close it down. And third which I believe is actually the most important, the single factor that has eaten like a cancer into our system, is our system of awards, prizes and recognitions in higher level science in India today and that is taken as the only reckoning of success. So, I think, these three things are easy to do then there are long-term things. I think it’s a question of having the courage and the honesty to admit that things are not okay. Try to look for the basic causes. If you do the thing correctly, doesn’t matter how long it takes, but if you start the thing wrong, then you will never get there.

哺乳類(イタチ)間で感染可能な鳥インフルエンザウイルスの作成過程の公表は、アメリカ合衆国バイオセキュリティ国家科学諮問委員会が許可を出し、科学者による解説が既に行われた。しかし、武器として使用可能な技術の輸出規制により、情報はオランダ国内にとどまっている。4月末に規制が解かれた後は、情報が拡散し、安全性に問題のある場所で実験が行われる可能性がでてくる。一方でこの件に関して当局は閉鎖的すぎるとの意見もある

Richard Van Noorden: Well, it seems like the dust is settling on this enormous controversy about whether researchers are allowed to publish papers in which they mutated the avian flu virus to be transmittable between mammals between ferrets. Now you remember that last year, a US advisory board said that this stuff shouldn’t be published and the papers should be censored and there was a lot of debate about that. Eventually last week, this National Science Advisory Board for Biosecurity revised what it had thought earlier and said, yeah, these studies can be published and at the meeting of the Royal Society in London last week, scientists actually described what they’ve done which in turn wasn’t entirely clear.

Richard Van Noorden: The problem is that at the moment, it looks like national export controls might prevent some of the information being published, even though this board says that these papers can be published, say export control laws, what governments put in place to limit the shipment of technologies that could be used for weapons and at the moment, the Dutch government has slapped export controls on the information in the paper and this is why the meeting in London, while Yoshihiro Kawaoka at the University of Wisconsin-Madison could talk about his paper on which the US government had lifted export controls Ron Fouchier at Rotterdam in Netherlands, he said, he couldn’t talk about his paper because export controls was still in place from the Dutch government. Now if that issue gets resolved, as it might well be by the end of April, other people at the meeting said well the real problem is that there might be some sort of worldwide proliferation of research on flu mutation in labs that are not safe as the ones in the Netherlands and in the United States, where this work is done.

Richard Van Noorden: Well, right now, there’s a moratorium on any research to make flu viruses more transmissible. The World Health Organization ordered this and one can assume there’s going to be more interest in this kind of work. They may point out ways in which if the flu virus picks up mutations that can become more transmissible. Now US and Dutch authorities are trying to assess the safety conditions for such research and within weeks they’re going to release their verdicts. But then lifting the moratorium might be seen as arrogant, people at the meeting worried because US law makers still want to have hearings on this. there’s a bit of feeling that these researchers are keeping these questions within their close-net community and not letting bioethicists and the wider public have a really debate on this matter.

幹細胞を使った未認可の治療が中国で盛んだが、政府が規制に乗り出した。長期的な予後観察の必要な病気の治療への使用は特に問題がある。

Richard Van Noorden: There’s a Nature investigation this week on the many businesses in China, who’re offering stem cell treatments for conditions like autism, Parkinson’s and multiple sclerosis costing anywhere between 30,000 and 200,000 dollars for injections. Now for years, these businesses have been offering these kinds of treatments. It’s all readily available on their web sites and it all looks very approved and safe, although they kind of readily admit that there’s not much data out there. Actually this isn’t the case. None of these stem cell treatments are approved and in January, the Chinese Health Ministry, recognizing this difficult situation tried to enforce a package of rules on the industry banning unapproved stem cell trials and telling local health authorities to halt any unapproved use of stem cells in their regions.

Richard Van Noorden: We talked to stem cell experts, who say the therapies aren’t ready for clinics and that even if the clinic says they’re safe they might endanger patient’s health. So Oliver Cooper who’s at the stem cell facility of the Neuroregeneration Institute in the McLean Hospital in the Massachusetts, he’s a specialist in Parkinson’s and talking about Tong Yuan’s treatment for Parkinson’s, he said, you know, these products could provide anecdotal poorly controlled transient improvements in the patients, but Parkinson’s disease patients need long-term therapies. It’s no good treating someone and saying, oh, after a few weeks, they seem to be getting better and we sent them away, they went back to another country. You need long-term followup, which is not obvious that these clinics are doing.

9つの惑星がある太陽系が見つかった。遠いので見えないが、惑星の重力による太陽の回転の揺らぎを計算すると分かる。調査が終わっていない太陽系がまだ2000あり、いずれもっと大きな太陽系が多数見つかるだろう。地球のように居住可能な惑星はなさそうだが探し続けている。

Richard Van Noorden: There’s a solar system outside our own which has more planets than us. We have been beaten. This is according to a reanalysis of data taken by the High Accuracy Radial velocity Planet Searcher which has this great acronym HARPS. It’s a telescope in Chile. It looked at the star system HD10180 and it’s got 9 planets. According to Mikko Tuomi who’s at the Center for Astrophysics Research at Hertfordshire in the UK, now when this data first came out in 2010, the HARPS team said that the solar system only had five planets or may be six or seven, but they were kind of looking at this for can the data support evidence for the 7th planet, for an 8th planet and this guy has taken a slightly different statistical approach saying if we look at all possible scenarios, which is most consistent with the data in total and he says there’s a 99.7% probability that there are 9 planets in the solar system. Remember that the only way you can see these planets is to look for wobbles in the star that they’re orbiting. You cannot see these planets directly because they are too far away.

Richard Van Noorden: Well, basically it comes down to can we detect the planets out there because they’re very small. When they get to the size of earth or smaller, then it would have much effect on their star’s wobble. So, we’re spotting these solar systems. We’ve seen may be 200-300 solar systems, 700 planets confirmed, there’s may be another 2000 candidates. So, I should expect to find our solar system’s importance rapidly dwindles to something like mid-size largeness. So, right now, it’s out there at number 2, but we might see it fall away in future years.

Richard Van Noorden: Nope, none of them look habitable. It’s proving quite difficult to find a planet that is like earth and has the right conditions. So, these 8th and 9th planets in the system are 5 and twice the mass of earth respectively and of course very far away from their stars and much too cold to support life, but we’re still searching. So, that is the dream for all and this kind of research just find that earth twin out there.

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