Synthetic studies on pterin glycosides: the first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin

L-Rhamnose was led, in a 14-step-sequence, to N2-(N,N-dimethylaminomethylene)-1′-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]biopterin (23), an appropriately protected precursor for 2′-O-glycosylation, while 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)-α-d-glucopyranosyl bromide (32), a novel glycosyl donor, was efficiently prepared from d-glucose in 8 steps. The first synthesis of 2′-O-(α-d-glucopyranosyl)biopterin (2a) was achieved by treatment of the key intermediate 23 with 32 in the presence of silver triflate and tetramethylurea, followed by successive removal of the protecting groups

Latitudinal gradient of spruce forest understory and tundra phenology in Alaska as observed from satellite and ground-based data

The latitudinal gradient of the start of the growing season (SOS) and the end of the growing season (EOS) were quantified in Alaska (61°N to 71°N) using satellite-based and ground-based datasets. The Alaskan evergreen needleleaf forests are sparse and the understory vegetation has a substantial impact on the satellite signal. We evaluated SOS and EOS of understory and tundra vegetation using time-lapse camera images. From the comparison of three SOS algorithms for determining SOS from two satellite datasets (SPOT-VEGETATION and Terra-MODIS), we found that the satellite-based SOS timing was consistent with the leaf emergence of the forest understory and tundra vegetation. The ensemble average of SOS over all satellite algorithms can be used as a measure of spring leaf emergence for understory and tundra vegetation. In contrast, the relationship between the ground-based and satellite-based EOSs was not as strong as that of SOS both for boreal forest and tundra sites because of the large biases between those two EOSs (19 to 26 days). The satellite-based EOS was more relevant to snowfall events than the senescence of understory or tundra. The plant canopy radiative transfer simulation suggested that 84–86% of the NDVI seasonal amplitude could be a reasonable threshold for the EOS determination. The latitudinal gradients of SOS and EOS evaluated by the satellite and ground data were consistent and the satellite-derived SOS and EOS were 3.5 to 5.7 days degree− 1 and − 2.3 to − 2.7 days degree− 1, which corresponded to the spring (May) temperature sensitivity of − 2.5 to − 3.9 days °C− 1 in SOS and the autumn (August and September) temperature sensitivity of 3.0 to 4.6 days °C− 1 in EOS. This demonstrates the possible impact of phenology in spruce forest understory and tundra ecosystems in response to climate change in the warming Artic and sub-Arctic regions

Testis-Specific Histone Variant H3t Gene Is Essential for Entry into Spermatogenesis

Jun Ueda, Akihito Harada, Takashi Urahama, Shinichi Machida, Kazumitsu Maehara, Masashi Hada, Yoshinori Makino, Jumpei Nogami, Naoki Horikoshi, Akihisa Osakabe, Hiroyuki Taguchi, Hiroki Tanaka, Hiroaki Tachiwana, Tatsuma Yao, Minami Yamada, Takashi Iwamoto, Ayako Isotani, Masahito Ikawa, Taro Tachibana, Yuki Okada, Hiroshi Kimura, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Kazuo Yamagata, Testis-Specific Histone Variant H3t Gene Is Essential for Entry into Spermatogenesis, Cell Reports, Volume 18, Issue 3, 2017, Pages 593-600, ISSN 2211-1247, https://doi.org/10.1016/j.celrep.2016.12.065

A High-Yielding Rice Cultivar “Takanari” Shows No N Constraints on CO2 Fertilization

Enhancing crop yield response to elevated CO2 concentrations (E-[CO2]) is an important adaptation measure to climate change. A high-yielding indica rice cultivar “Takanari” has recently been identified as a potential candidate for high productivity in E-[CO2] resulting from its large sink and source capacities. To fully utilize these traits, nitrogen should play a major role, but it is unknown how N levels influence the yield response of Takanari to E-[CO2]. We therefore compared grain yield and quality of Takanari with those of Koshihikari, a standard japonica cultivar, in response to Free-Air CO2 enrichment (FACE, +200 μmol mol−1) under three N levels (0, 8, and 12 g m−2) over three seasons. The biomass of both cultivars increased under E-[CO2] at all N levels; however, the harvest index decreased under E-[CO2] in the N-limited treatment for Koshihikari but not for Takanari. The decreased harvest index of Koshihikari resulted from limited enhancement of spikelet number under N-limitation. In contrast, spikelet number increased in E-[CO2] in Takanari even without N application, resulting in significant yield enhancement, averaging 18% over 3 years, whereas Koshihikari exhibited virtually no increase in yield in E-[CO2] under the N-limited condition. Grain appearance quality of Koshihikari was severely reduced by E-[CO2], most notably in N-limited and hot conditions, by a substantial increase in chalky grain, but chalky grain % did not increase in E-[CO2] even without N fertilizer. These results indicated that Takanari could retain its high yield advantage over Koshihikari with limited increase in chalkiness even under limited N conditions and that it could be a useful genetic resource for improving N use efficiency under E-[CO2]

精神疾患におけるマイクログリア由来ニューレグリン発現

Several studies have revealed that neuregulins (NRGs) are involved in brain function and psychiatric disorders. While NRGs have been regarded as neuron- or astrocyte-derived molecules, our research has revealed that microglia also express NRGs, levels of which are markedly increased in activated microglia. Previous studies have indicated that microglia are activated in the brains of individuals with autism spectrum disorder (ASD). Therefore, we investigated microglial NRG mRNA expression in multiple lines of mice considered models of ASD. Intriguingly, microglial NRG expression significantly increased in BTBR and socially-isolated mice, while maternal immune activation (MIA) mice exhibited identical NRG expression to controls. Furthermore, we observed a positive correlation between NRG expression in microglia and peripheral blood mononuclear cells (PBMCs) in mice, suggesting that NRG expression in human PBMCs may mirror microglia-derived NRG expression in the human brain. To translate these findings for application in clinical psychiatry, we measured levels of NRG1 splice-variant expression in clinically available PBMCs of patients with ASD. Levels of NRG1 type III expression in PBMCs were positively correlated with impairments in social interaction in children with ASD (as assessed using the Autistic Diagnostic Interview-Revised test: ADI-R). These findings suggest that immune cell-derived NRGs may be implicated in the pathobiology of psychiatric disorders such as ASD.博士（医学）・乙第1404号・平成29年6月28日Copyright © 2017 Elsevier Inc. All rights reserved

Representativeness of Eddy-Covariance flux footprints for areas surrounding AmeriFlux sites

Large datasets of greenhouse gas and energy surface-atmosphere fluxes measured with the eddy-covariance technique (e.g., FLUXNET2015, AmeriFlux BASE) are widely used to benchmark models and remote-sensing products. This study addresses one of the major challenges facing model-data integration: To what spatial extent do flux measurements taken at individual eddy-covariance sites reflect model- or satellite-based grid cells? We evaluate flux footprints—the temporally dynamic source areas that contribute to measured fluxes—and the representativeness of these footprints for target areas (e.g., within 250–3000 m radii around flux towers) that are often used in flux-data synthesis and modeling studies. We examine the land-cover composition and vegetation characteristics, represented here by the Enhanced Vegetation Index (EVI), in the flux footprints and target areas across 214 AmeriFlux sites, and evaluate potential biases as a consequence of the footprint-to-target-area mismatch. Monthly 80% footprint climatologies vary across sites and through time ranging four orders of magnitude from 103 to 107 m2 due to the measurement heights, underlying vegetation- and ground-surface characteristics, wind directions, and turbulent state of the atmosphere. Few eddy-covariance sites are located in a truly homogeneous landscape. Thus, the common model-data integration approaches that use a fixed-extent target area across sites introduce biases on the order of 4%–20% for EVI and 6%–20% for the dominant land cover percentage. These biases are site-specific functions of measurement heights, target area extents, and land-surface characteristics. We advocate that flux datasets need to be used with footprint awareness, especially in research and applications that benchmark against models and data products with explicit spatial information. We propose a simple representativeness index based on our evaluations that can be used as a guide to identify site-periods suitable for specific applications and to provide general guidance for data use

Curated genome annotation of Oryza sativa ssp. japonica and comparative genome analysis with Arabidopsis thaliana

We present here the annotation of the complete genome of rice Oryza sativa L. ssp. japonica cultivar Nipponbare. All functional annotations for proteins and non-protein-coding RNA (npRNA) candidates were manually curated. Functions were identified or inferred in 19,969 (70%) of the proteins, and 131 possible npRNAs (including 58 antisense transcripts) were found. Almost 5000 annotated protein-coding genes were found to be disrupted in insertional mutant lines, which will accelerate future experimental validation of the annotations. The rice loci were determined by using cDNA sequences obtained from rice and other representative cereals. Our conservative estimate based on these loci and an extrapolation suggested that the gene number of rice is ~32,000, which is smaller than previous estimates. We conducted comparative analyses between rice and Arabidopsis thaliana and found that both genomes possessed several lineage-specific genes, which might account for the observed differences between these species, while they had similar sets of predicted functional domains among the protein sequences. A system to control translational efficiency seems to be conserved across large evolutionary distances. Moreover, the evolutionary process of protein-coding genes was examined. Our results suggest that natural selection may have played a role for duplicated genes in both species, so that duplication was suppressed or favored in a manner that depended on the function of a gene

Fluid flow-induced left-right asymmetric decay of Dand5 mRNA in the mouse embryo requires a Bicc1-Ccr4 RNA degradation complex

Molecular left-right (L-R) asymmetry is established at the node of the mouse embryo as a result of the sensing of a leftward fluid flow by immotile cilia of perinodal crown cells and the consequent degradation of Dand5 mRNA on the left side. We here examined how the fluid flow induces Dand5 mRNA decay. We found that the first 200 nucleotides in the 3′ untranslated region (3′-UTR) of Dand5 mRNA are necessary and sufficient for the left-sided decay and to mediate the response of a 3′-UTR reporter transgene to Ca2+, the cation channel Pkd2, the RNA-binding protein Bicc1 and their regulation by the flow direction. We show that Bicc1 preferentially recognizes GACR and YGAC sequences, which can explain the specific binding to a conserved GACGUGAC motif located in the proximal Dand5 3′-UTR. The Cnot3 component of the Ccr4-Not deadenylase complex interacts with Bicc1 and is also required for Dand5 mRNA decay at the node. These results suggest that Ca2+ currents induced by leftward fluid flow stimulate Bicc1 and Ccr4-Not to mediate Dand5 mRNA degradation specifically on the left side of the node

Accurate detection of year-to-year variability of plant phenology in an open-canopy black spruce forest in Alaska

第6回極域科学シンポジウム分野横断セッション：[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日（木）　国立極地研究所１階交流アトリウ