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Novel chemical process a first step to making nuclear fuel with fire 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:0/0  |  提交时间:2020/11/30
To recreate ancient recipes, check out the vestiges of clay pots 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:2/0  |  提交时间:2020/09/14
X-rays size up protein structure at the 'heart' of COVID-19 virus 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:1/0  |  提交时间:2020/06/28
Human-derived mercury shown to pollute the world's deepest ocean trenches 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:17/0  |  提交时间:2020/06/23
PFAS present throughout the Yadkin-Pee Dee river food chain 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:33/0  |  提交时间:2020/06/09
Large-scale analysis of protein arginine methylation by mass spectrometry 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:0/0  |  提交时间:2020/05/26
Cahokia's rise parallels onset of corn agriculture 新闻
来源平台:EurekAlert. 发布日期:2020
作者:  admin
收藏  |  浏览/下载:1/0  |  提交时间:2020/05/15
Metabolic heterogeneity confers differences in melanoma metastatic potential 期刊论文
NATURE, 2020, 577 (7788) : 115-+
作者:  Tasdogan, Alpaslan;  Faubert, Brandon;  Ramesh, Vijayashree;  Ubellacker, Jessalyn M.;  Shen, Bo;  Solmonson, Ashley;  Murphy, Malea M.;  Gu, Zhimin;  Gu, Wen;  Martin, Misty;  Kasitinon, Stacy Y.;  Vandergriff, Travis;  Mathews, Thomas P.;  Zhao, Zhiyu;  Schadendorf, Dirk;  DeBerardinis, Ralph J.;  Morrison, Sean J.
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03

Metastasis requires cancer cells to undergo metabolic changes that are poorly understood(1-3). Here we show that metabolic differences among melanoma cells confer differences in metastatic potential as a result of differences in the function of the MCT1 transporter. In vivo isotope tracing analysis in patient-derived xenografts revealed differences in nutrient handling between efficiently and inefficiently metastasizing melanomas, with circulating lactate being a more prominent source of tumour lactate in efficient metastasizers. Efficient metastasizers had higher levels of MCT1, and inhibition of MCT1 reduced lactate uptake. MCT1 inhibition had little effect on the growth of primary subcutaneous tumours, but resulted in depletion of circulating melanoma cells and reduced the metastatic disease burden in patient-derived xenografts and in mouse melanomas. In addition, inhibition of MCT1 suppressed the oxidative pentose phosphate pathway and increased levels of reactive oxygen species. Antioxidants blocked the effects of MCT1 inhibition on metastasis. MCT1(high) and MCT1(-/low) cells from the same melanomas had similar capacities to form subcutaneous tumours, but MCT1(high) cells formed more metastases after intravenous injection. Metabolic differences among cancer cells thus confer differences in metastatic potential as metastasizing cells depend on MCT1 to manage oxidative stress.


  
Preparation of cyclohexene isotopologues and stereoisotopomers from benzene 期刊论文
NATURE, 2020, 581 (7808) : 288-+
作者:  Shimazaki, Yuya;  Schwartz, Ido;  Watanabe, Kenji;  Taniguchi, Takashi;  Kroner, Martin;  Imamoglu, Atac
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/03

The hydrogen isotopes deuterium (D) and tritium (T) have become essential tools in chemistry, biology and medicine(1). Beyond their widespread use in spectroscopy, mass spectrometry and mechanistic and pharmacokinetic studies, there has been considerable interest in incorporating deuterium into drug molecules(1). Deutetrabenazine, a deuterated drug that is promising for the treatment of Huntington'  s disease(2), was recently approved by the United States'  Food and Drug Administration. The deuterium kinetic isotope effect, which compares the rate of a chemical reaction for a compound with that for its deuterated counterpart, can be substantial(1,3,4). The strategic replacement of hydrogen with deuterium can affect both the rate of metabolism and the distribution of metabolites for a compound(5), improving the efficacy and safety of a drug. The pharmacokinetics of a deuterated compound depends on the location(s) of deuterium. Although methods are available for deuterium incorporation at both early and late stages of the synthesis of a drug(6,7), these processes are often unselective and the stereoisotopic purity can be difficult to measure(7,8). Here we describe the preparation of stereoselectively deuterated building blocks for pharmaceutical research. As a proof of concept, we demonstrate a four-step conversion of benzene to cyclohexene with varying degrees of deuterium incorporation, via binding to a tungsten complex. Using different combinations of deuterated and proteated acid and hydride reagents, the deuterated positions on the cyclohexene ring can be controlled precisely. In total, 52 unique stereoisotopomers of cyclohexene are available, in the form of ten different isotopologues. This concept can be extended to prepare discrete stereoisotopomers of functionalized cyclohexenes. Such systematic methods for the preparation of pharmacologically active compounds as discrete stereoisotopomers could improve the pharmacological and toxicological properties of drugs and provide mechanistic information related to their distribution and metabolism in the body.


Cyclohexene isotopologues and stereoisotopomers with varying degrees of deuteration are formed by binding a tungsten complex to benzene, which facilitates the selective incorporation of deuterium into any position on the ring.


  
Ruthenium isotope vestige of Earth's pre-late-veneer mantle preserved in Archaean rocks 期刊论文
NATURE, 2020, 579 (7798) : 240-+
作者:  Abadie, Valerie;  Kim, Sangman M.;  Lejeune, Thomas;  Palanski, Brad A.;  Ernest, Jordan D.;  Tastet, Olivier;  Voisine, Jordan;  Discepolo, Valentina;  Marietta, Eric, V;  Hawash, Mohamed B. F.;  Ciszewski, Cezary;  Bouziat, Romain;  Panigrahi, Kaushik;  Horwath, Irina;  Zurenski, Matthew A.;  Lawrence, Ian;  Dumaine, Anne;  Yotova, Vania;  Grenier, Jean-Christophe;  Murray, Joseph A.;  Khosla, Chaitan;  Barreiro, Luis B.;  Jabri, Bana
收藏  |  浏览/下载:31/0  |  提交时间:2020/05/13

The accretion of volatile-rich material from the outer Solar System represents a crucial prerequisite for Earth to develop oceans and become a habitable planet(1-4). However, the timing of this accretion remains controversial(5-8). It has been proposed that volatile elements were added to Earth by the late accretion of a late veneer consisting of carbonaceous-chondrite-like material after core formation had ceased(6,9,10). This view could not be reconciled with the ruthenium (Ru) isotope composition of carbonaceous chondrites(5,11), which is distinct from that of the modern mantle(12), or of any known meteorite group(5). As a possible solution, Earth'  s pre-late-veneer mantle could already have contained a fraction of Ru that was not fully extracted by core formation(13). The presence of such pre-late-veneer Ru can only be established if its isotope composition is distinct from that of the modern mantle. Here we report the first high-precision, mass-independent Ru isotope compositions for Eoarchaean ultramafic rocks from southwest Greenland, which display a relative Ru-100 excess of 22 parts per million compared with the modern mantle value. This Ru-100 excess indicates that the source of the Eoarchaean rocks already contained a substantial fraction of Ru before the accretion of the late veneer. By 3.7 billion years ago, the mantle beneath southwest Greenland had not yet fully equilibrated with late accreted material. Otherwise, no Ru isotopic difference relative to the modern mantle would be observed. If constraints from other highly siderophile elements besides Ru are also considered(14), the composition of the modern mantle can only be reconciled if the late veneer contained substantial amounts of carbonaceous-chondrite-like materials with their characteristic Ru-100 deficits. These data therefore relax previous constraints on the late veneer and are consistent with volatile-rich material from the outer Solar System being delivered to Earth during late accretion.