利用环介导恒温扩增法简易诊断松萎蔫病Takuya Aikawa,Natsumi Kanzak,Taisei Kikuch

诊断松萎蔫病的传统方法是从木质组织中分离松材线虫,然后用显微镜进行形态学鉴定。基于DNA分子检测的方法尽管很灵敏,不需要固定发育阶段的松材线虫,但是仍然需要用Baermann 漏斗法分离线虫,并且需要昂贵的仪器。笔者研发了利用环介导恒温扩增法检测松材线虫的存在,该方法包括：(1) 从木块中提取DNA;(2) DNA 扩增;(3) 通过反应溶液的颜色做出诊断。该方法仅使用培养箱且整个过程只需要90 min,比以往方法更加简便和快速。     

Structure of the human histamine H1 receptor complex with doxepin

The biogenic amine histamine is an important pharmacological mediator involved in pathophysiological processes such as allergies and inflammations. Histamine H(1) receptor (H(1)R) antagonists are very effective drugs alleviating the symptoms of allergic reactions. Here we show the crystal structure of the H(1)R complex with doxepin, a first-generation H(1)R antagonist. Doxepin sits deep in the ligand-binding pocket and directly interacts with Trp?428(6.48), a highly conserved key residue in G-protein-coupled-receptor activation. This well-conserved pocket with mostly hydrophobic nature contributes to the low selectivity of the first-generation compounds. The pocket is associated with an anion-binding region occupied by a phosphate ion. Docking of various second-generation H(1)R antagonists reveals that the unique carboxyl group present in this class of compounds interacts with Lys?191(5.39) and/or Lys?179(ECL2), both of which form part of the anion-binding region. This region is not conserved in other aminergic receptors, demonstrating how minor differences in receptors lead to pronounced selectivity differences with small molecules. Our study sheds light on the molecular basis of H(1)R antagonist specificity against H(1)R.     

Structure of the human M2 muscarinic acetylcholine receptor bound to an antagonist

The parasympathetic branch of the autonomic nervous system regulates the activity of multiple organ systems. Muscarinic receptors are G-protein-coupled receptors that mediate the response to acetylcholine released from parasympathetic nerves. Their role in the unconscious regulation of organ and central nervous system function makes them potential therapeutic targets for a broad spectrum of diseases. The M2 muscarinic acetylcholine receptor (M2 receptor) is essential for the physiological control of cardiovascular function through activation of G-protein-coupled inwardly rectifying potassium channels, and is of particular interest because of its extensive pharmacological characterization with both orthosteric and allosteric ligands. Here we report the structure of the antagonist-bound human M2 receptor, the first human acetylcholine receptor to be characterized structurally, to our knowledge. The antagonist 3-quinuclidinyl-benzilate binds in the middle of a long aqueous channel extending approximately two-thirds through the membrane. The orthosteric binding pocket is formed by amino acids that are identical in all five muscarinic receptor subtypes, and shares structural homology with other functionally unrelated acetylcholine binding proteins from different species. A layer of tyrosine residues forms an aromatic cap restricting dissociation of the bound ligand. A binding site for allosteric ligands has been mapped to residues at the entrance to the binding pocket near this aromatic cap. The structure of the M2 receptor provides insights into the challenges of developing subtype-selective ligands for muscarinic receptors and their propensity for allosteric regulation.     

Optimal isotope labelling for NMR protein structure determinations

Nuclear-magnetic-resonance spectroscopy can determine the three-dimensional structure of proteins in solution. However, its potential has been limited by the difficulty of interpreting NMR spectra in the presence of broadened and overlapping resonance lines and low signal-to-noise ratios. Here we present stereo-array isotope labelling (SAIL), a technique that can overcome many of these problems by applying a complete stereospecific and regiospecific pattern of stable isotopes that is optimal with regard to the quality and information content of the resulting NMR spectra. SAIL uses exclusively chemically and enzymatically synthesized amino acids for cell-free protein expression. We demonstrate for the 17-kDa protein calmodulin and the 41-kDa maltodextrin-binding protein that SAIL offers sharpened lines, spectral simplification without loss of information, and the ability to rapidly collect the structural restraints required to solve a high-quality solution structure for proteins twice as large as commonly solved by NMR. It thus makes a large class of proteins newly accessible to detailed solution structure determination.     

Water solubility in orthopyroxene: Dependence on temperature and Al content

The water solubility in Al-Fe-Mg orthopyroxene [(Mg,Fe,Al)(Si,Al)O₃: X _Fe = 0.1] was investigated as a function of temperature and Al contents. Experiments were performed at 10 kbar with temperatures ranging from 800 to 1200°C under water-saturated conditions. Water contents in the (Mg,Fe)SiO₃-H₂O-Al₂O₃ system were determined using unpolarized Fourier transform infrared spectroscopy. The present results show that water solubility in Al-bearing orthopyroxene decreases systematically with temperature from approximately 1 weight % at 800°C to 568 ± 58 ppm at 1200°C and increase significantly with increasing Al₂O₃ contents under the same annealing temperature and pressure. Combined with published results on the dependence of hydroxyl solubility on water fugacity and pressure, the present results can be described by the relation $C_{OH} = A(T)f_{H_2 O}^{n = 0.5} \exp \left( { - \frac{{\Delta H^{1bar} + \Delta V^{solid} P}} {{RT}}} \right)$ where A = 0.0024 ± 0.0015 ppm/bar^0.5, ΔH ^1bar = ?103.348 ± 9.768 kJ/mol, and solid ΔV ^solid = 9.2 ± 1.1 cm³/mol. This equation implies that the incorporation mechanism of water in aluminous orthopyroxene involves the isolated OH groups. Based on the experimentally established solubility model used in this study, it is suggested that water solubility decreases with increasing temperature under typical upper mantle pressure. The predicted temperature dependence of water solubility is in good agreement with the previous experimental observations in Al-bearing orthopyroxene, but the opposite dependence is observed in Al-free systems. Moreover, our estimation of the water solubility in upper-mantle minerals as a function of depth for a typical oceanic geotherm might be of potential importance in interpreting the geophysical observations.     

Semi-annual oscillations in Saturn's low-latitude stratospheric temperatures

Observations of oscillations of temperature and wind in planetary atmospheres provide a means of generalizing models for atmospheric dynamics in a diverse set of planets in the Solar System and elsewhere. An equatorial oscillation similar to one in the Earth's atmosphere has been discovered in Jupiter. Here we report the existence of similar oscillations in Saturn's atmosphere, from an analysis of over two decades of spatially resolved observations of its 7.8-microm methane and 12.2-microm ethane stratospheric emissions, where we compare zonal-mean stratospheric brightness temperatures at planetographic latitudes of 3.6 degrees and 15.5 degrees in both the northern and the southern hemispheres. These results support the interpretation of vertical and meridional variability of temperatures in Saturn's stratosphere as a manifestation of a wave phenomenon similar to that on the Earth and in Jupiter. The period of this oscillation is 14.8 +/- 1.2 terrestrial years, roughly half of Saturn's year, suggesting the influence of seasonal forcing, as is the case with the Earth's semi-annual oscillation.     

Cloning of adiponectin receptors that mediate antidiabetic metabolic effects

Adiponectin (also known as 30-kDa adipocyte complement-related protein; Acrp30) is a hormone secreted by adipocytes that acts as an antidiabetic and anti-atherogenic adipokine. Levels of adiponectin in the blood are decreased under conditions of obesity, insulin resistance and type 2 diabetes. Administration of adiponectin causes glucose-lowering effects and ameliorates insulin resistance in mice. Conversely, adiponectin-deficient mice exhibit insulin resistance and diabetes. This insulin-sensitizing effect of adiponectin seems to be mediated by an increase in fatty-acid oxidation through activation of AMP kinase and PPAR-alpha. Here we report the cloning of complementary DNAs encoding adiponectin receptors 1 and 2 (AdipoR1 and AdipoR2) by expression cloning. AdipoR1 is abundantly expressed in skeletal muscle, whereas AdipoR2 is predominantly expressed in the liver. These two adiponectin receptors are predicted to contain seven transmembrane domains, but to be structurally and functionally distinct from G-protein-coupled receptors. Expression of AdipoR1/R2 or suppression of AdipoR1/R2 expression by small-interfering RNA supports our conclusion that they serve as receptors for globular and full-length adiponectin, and that they mediate increased AMP kinase and PPAR-alpha ligand activities, as well as fatty-acid oxidation and glucose uptake by adiponectin.     

Whole-genome sequencing of liver cancers identifies etiological influences on mutation patterns and recurrent mutations in chromatin regulators

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. We sequenced and analyzed the whole genomes of 27 HCCs, 25 of which were associated with hepatitis B or C virus infections, including two sets of multicentric tumors. Although no common somatic mutations were identified in the multicentric tumor pairs, their whole-genome substitution patterns were similar, suggesting that these tumors developed from independent mutations, although their shared etiological backgrounds may have strongly influenced their somatic mutation patterns. Statistical and functional analyses yielded a list of recurrently mutated genes. Multiple chromatin regulators, including ARID1A, ARID1B, ARID2, MLL and MLL3, were mutated in ～50% of the tumors. Hepatitis B virus genome integration in the TERT locus was frequently observed in a high clonal proportion. Our whole-genome sequencing analysis of HCCs identified the influence of etiological background on somatic mutation patterns and subsequent carcinogenesis, as well as recurrent mutations in chromatin regulators in HCCs.     

利用环介导恒温扩增法简易诊断松萎蔫病

诊断松萎蔫病的传统方法是从木质组织中分离松材线虫,然后用显微镜进行形态学鉴定.基于DNA分子检测的方法尽管很灵敏,不需要固定发育阶段的松材线虫,但是仍然需要用Baermann漏斗法分离线虫,并且需要昂贵的仪器.笔者研发了利用环介导恒温扩增法检测松材线虫的存在,该方法包括:(1)从木块中提取DNA；(2) DNA扩增；(3)通过反应溶液的颜色做出诊断.该方法仅使用培养箱且整个过程只需要90 min,比以往方法更加简便和快速.     

Coseismic and postseismic slip of the 2011 magnitude-9 Tohoku-Oki earthquake

Most large earthquakes occur along an oceanic trench, where an oceanic plate subducts beneath a continental plate. Massive earthquakes with a moment magnitude, M(w), of nine have been known to occur in only a few areas, including Chile, Alaska, Kamchatka and Sumatra. No historical records exist of a M(w) = 9 earthquake along the Japan trench, where the Pacific plate subducts beneath the Okhotsk plate, with the possible exception of the ad 869 Jogan earthquake, the magnitude of which has not been well constrained. However, the strain accumulation rate estimated there from recent geodetic observations is much higher than the average strain rate released in previous interplate earthquakes. This finding raises the question of how such areas release the accumulated strain. A megathrust earthquake with M(w) = 9.0 (hereafter referred to as the Tohoku-Oki earthquake) occurred on 11 March 2011, rupturing the plate boundary off the Pacific coast of northeastern Japan. Here we report the distributions of the coseismic slip and postseismic slip as determined from ground displacement detected using a network based on the Global Positioning System. The coseismic slip area extends approximately 400?km along the Japan trench, matching the area of the pre-seismic locked zone. The afterslip has begun to overlap the coseismic slip area and extends into the surrounding region. In particular, the afterslip area reached a depth of approximately 100?km, with M(w) = 8.3, on 25 March 2011. Because the Tohoku-Oki earthquake released the strain accumulated for several hundred years, the paradox of the strain budget imbalance may be partly resolved. This earthquake reminds us of the potential for M(w)?≈?9 earthquakes to occur along other trench systems, even if no past evidence of such events exists. Therefore, it is imperative that strain accumulation be monitored using a space geodetic technique to assess earthquake potential.