日本文化を教えて - カンタベリー大学アジア研究学部（NZ）

Fatty acid amide hydrolase (FAAH), a membrane-anchored enzyme responsible for the termination of endocannabinoid signalling, is an attractive target for treating conditions such as pain and anxiety. Inhibitors of the enzyme, optimized using rodent FAAH, are known but their pharmacology and medicinal chemistry properties on the human FAAH are missing. Therefore recombinant human enzyme would represent a powerful tool to evaluate new drug candidates. However, the production of high amounts of enzyme is hampered by the known refractiveness of FAAH to overexpression. Here, we report the successful overexpression of rat and human FAAH as a fusion to the E. coli maltose-binding protein, retaining catalytic properties of native FAAH. Several known FAAH inhibitors were tested and differences in their potencies toward the human and rat FAAH were found, underscoring the importance of using a human FAAH in the development of inhibitors

Analysis of the dust evolution in the circumstellar disks of TTauri stars

We present a compositional analysis of 8-13um spectra of 32 young stellar objects (YSOs). Our sample consists of 5 intermediate-mass stars and 27 low-mass stars. While the spectra and first scientific results have already been published by Przygodda et al. (2003) and Kessler-Silacci et al. (2004) we perform a more detailed analysis of the 10um silicate feature. In our analysis we assume that this emission feature can be represented by a linear superposition of the wavelength-dependent opacity $\kappa_{\rm abs}(\lambda)$ describing the optical properties of silicate grains with different chemical composition, structure, and grain size. The determination of an adequate fitting equation is another goal of this study. Using a restricted number of fitting parameters we investigate which silicate species are necessary for the compositional fitting. Particles with radii of 0.1um- and 1.5um consisting of amorphous olivine and pyroxene, forsterite, enstatite, and quartz have been considered. Only compact, homogeneous dust grains have been used in the presented fitting procedures. In this context we show that acceptable fitting results can also be achieved if emission properties of porous silicate grains are considered instead. Although some previous studies give reasons for the similarity between the dust in circumstellar disks of TTauri stars and Herbig Ae/Be stars, a quantitative comparison has been missing, so far. Therefore, we conclude with a discussion of the results of a 10um spectroscopic survey of van Boekel et al. (2005) who focus on Herbig Ae/Be stars, the higher mass counterparts of T Tauri stars and draw comparisons to this and other studies. We find that the results of our study of T Tauri systems partly agree with previous studies of Herbig Ae/Be stars.Comment: 17 pages, 6 figure

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

The ATHENA X-ray Integral Field Unit (X-IFU)

The X-ray Integral Field Unit (X-IFU) is the high resolution X-ray spectrometer of the ESA Athena X-ray observatory. Over a field of view of 5' equivalent diameter, it will deliver X-ray spectra from 0.2 to 12 keV with a spectral resolution of 2.5 eV up to 7 keV on ∼ 5" pixels. The X-IFU is based on a large format array of super-conducting molybdenum-gold Transition Edge Sensors cooled at ∼ 90 mK, each coupled with an absorber made of gold and bismuth with a pitch of 249 μm. A cryogenic anti-coincidence detector located underneath the prime TES array enables the non X-ray background to be reduced. A bath temperature of ∼ 50 mK is obtained by a series of mechanical coolers combining 15K Pulse Tubes, 4K and 2K Joule-Thomson coolers which pre-cool a sub Kelvin cooler made of a 3He sorption cooler coupled with an Adiabatic Demagnetization Refrigerator. Frequency domain multiplexing enables to read out 40 pixels in one single channel. A photon interacting with an absorber leads to a current pulse, amplified by the readout electronics and whose shape is reconstructed on board to recover its energy with high accuracy. The defocusing capability offered by the Athena movable mirror assembly enables the X-IFU to observe the brightest X-ray sources of the sky (up to Crab-like intensities) by spreading the telescope point spread function over hundreds of pixels. Thus the X-IFU delivers low pile-up, high throughput (< 50%), and typically 10 eV spectral resolution at 1 Crab intensities, i.e. A factor of 10 or more better than Silicon based X-ray detectors. In this paper, the current X-IFU baseline is presented, together with an assessment of its anticipated performance in terms of spectral resolution, background, and count rate capability. The X-IFU baseline configuration will be subject to a preliminary requirement review that is scheduled at the end of 2018

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

Instrumentatio

Expression and Evolution of the Non-Canonically Translated Yeast Mitochondrial Acetyl-CoA Carboxylase Hfa1p

<div><p>The <i>Saccharomyces cerevisiae</i> genome encodes two sequence related acetyl-CoA carboxylases, the cytosolic Acc1p and the mitochondrial Hfa1p, required for respiratory function. Several aspects of expression of the <i>HFA1</i> gene and its evolutionary origin have remained unclear. Here, we determined the <i>HFA1</i> transcription initiation sites by 5′ RACE analysis. Using a novel “Stop codon scanning” approach, we mapped the location of the <i>HFA1</i> translation initiation site to an upstream AUU codon at position −372 relative to the annotated start codon. This upstream initiation leads to production of a mitochondrial targeting sequence preceding the ACC domains of the protein. <i>In silico</i> analyses of fungal <i>ACC</i> genes revealed conserved “cryptic” upstream mitochondrial targeting sequences in yeast species that have not undergone a whole genome duplication. Our Δ<i>hfa1</i> baker's yeast mutant phenotype rescue studies using the protoploid <i>Kluyveromyces lactis ACC</i> confirmed functionality of the cryptic upstream mitochondrial targeting signal. These results lend strong experimental support to the hypothesis that the mitochondrial and cytosolic acetyl-CoA carboxylases in <i>S. cerevisiae</i> have evolved from a single gene encoding both the mitochondrial and cytosolic isoforms. Leaning on a cursory survey of a group of genes of our interest, we propose that cryptic 5′ upstream mitochondrial targeting sequences may be more abundant in eukaryotes than anticipated thus far.</p></div

The W1536 8B Δ<i>hfa1</i> strain carrying plasmids with inserted stop codon mutation at position downstream of −372 resulted in unchanged lactate deficiency.

<p>Only stop codon mutations relevant to define the putative translation initiation site and controls are shown. The yeast cells were grown on media containing Glucose (SCD) or lactate (Lactate) as the sole carbon source at 33°C. Strains used for this study are W1536 8B, W1536 8B Δ<i>hfa1</i> or W1536 8B Δ<i>htd2</i> (respiratory deficient control) and the plasmids carried by the strains are indicated at the left side of the panels. YCp33: empty plasmid; HFA1: YCp33 <i>HFA1</i>; −381: YCp33 <i>HFA1</i> −381; −372: YCp33 <i>HFA1</i> −372; −363: YCp33<i>HFA1</i> −363. Only stop codon mutations relevant to define the putative translation initiation site and controls are shown. The results for other mutants shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114738#pone-0114738-g002" target="_blank">Fig. 2</a> can be found as supplementary data.</p

Schematic depiction of location of the introduced stop codons for stop –codon scanning assay and RNAse protection assay results.

<p>All nucleotide numbers are given respective to the annotated start codon at +1. Position −450 is the predicted transcribed but not translated region of <i>HFA1</i>. The underlined region up to position −216 region shows the putative minimum mitochondrial import sequence and upstream position −141 shows the end of the sequence similarity to <i>ACC1</i>. The ORFof <i>HFA1</i> annotated in the <i>Saccharomyces</i> Genome Database starts from +1. The stop codon found to lead to a respiratory deficient phenotype in the screen performed by Kursu <i>et al</i>. 2013 is located at −273 and 8 more stop codons at −282, −312, −360, −363, −372 −375 −378 and −381 were introduced upstream in the promoter region of <i>HFA1</i>.</p

Identification of the <i>HFA1</i> transcription initiation site by 5′RACE: The <i>HFA1</i> specific primer SP1 (Table 4) was used for the reverse transcription reaction to synthesize a first strand cDNA.

<p>a) Major 5′ RACE product (500 bp), b) Minor 5′RACE product (650 bp) and c) third band produced only occasionally.</p