Further expansion of distributional range of an introduced spider Badumna insignis in the eastern part of Tottori Prefecture (Results of the surveys in 2017).

2017 年の夏から秋にかけて鳥取県の東部を中心として外来種のクロガケジグモ（クモ目ウシオグモ科）の分布範囲を調査した。これまで本種が未確認の鳥取県西部でも数地点（境港市，米子市，大山町，日南町）調べたが，今回も生息は確認できなかった。鳥取県東部では，既知生息範囲から遠く離れた若桜町内や岩美町内でもそれぞれ1 地点で生息を確認した。離れているこれら2 地点を除いたほぼ連続的と考えられる鳥取市周辺の本種の今回の生息確認範囲は2014 年における生息確認範囲よりも広く，西は国道9 号線沿いの白兎海岸，南は国道53 号沿いに河原町布袋，国道29 号線沿いに八頭町下坂まで伸びていた（西へは約2.5 km，南には約6 km 拡大）。いっぽう，交通量の少ない鳥取市南西側の県道沿いには新規の拡大はみられず，本種の分布域の拡大に人の移動や物流が関係していることを示唆した。本種が生息する地点では在来種のクモの個体数が減少していた。クロガケジグモの個体数の多さが目立つのは，早くから本種の生息域となっている湖山町周辺が含まれる千代川以西・国体道路以北の鳥取市街地であった。 We surveyed distribution of an introduced spider Badumna insignis (Araneae: Desidae) in Tottori Prefecture in 2017. There were no sites where B. insignis was found in the western part of Tottori Prefecture, as reported in the former surveys. On the other hand, we found the species in Iwami-cho and Wakasa-cho, where B. insignis had not been found. Continuous range of distribution of the species in Tottori City expanded ca. 2.5 km toward west along the national route 9, and ca. 6 km toward south, along major national routes (Routes 29 and 53). On the other hand, there was no expansion of the species toward southwestern part of the city where only prefectural roads with a few traffic extend. These facts suggest that human movements and logistics help expansion of the spider. The individual number of native spiders at sites where B. insignis inhabits was much fewer than that at sites without B. insignis

Influx of nitrogen-rich material from the outer Solar System indicated by iron nitride in Ryugu samples

Large amounts of nitrogen compounds, such as ammonium salts, may be stored in icy bodies and comets, but the transport of these nitrogen-bearing solids into the near-Earth region is not well understood. Here, we report the discovery of iron nitride on magnetite grains from the surface of the near-Earth C-type carbonaceous asteroid Ryugu, suggesting inorganic nitrogen fixation. Micrometeoroid impacts and solar wind irradiation may have caused the selective loss of volatile species from major iron-bearing minerals to form the metallic iron. Iron nitride is a product of nitridation of the iron metal by impacts of micrometeoroids that have higher nitrogen contents than the CI chondrites. The impactors are probably primitive materials with origins in the nitrogen-rich reservoirs in the outer Solar System. Our observation implies that the amount of nitrogen available for planetary formation and prebiotic reactions in the inner Solar System is greater than previously recognized

A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss

Four‐dimensional‐STEM analysis of the phyllosilicate‐rich matrix of Ryugu samples

Ryugu asteroid grains brought back to the Earth by the Hayabusa2 space mission are pristine samples containing hydrated minerals and organic compounds. Here, we investigate the mineralogy of their phyllosilicate-rich matrix with four-dimensional scanning transmission electron microscopy (4D-STEM). We have identified and mapped the mineral phases at the nanometer scale (serpentine, smectite, pyrrhotite), observed the presence of Ni-bearing pyrrhotite, and identified the serpentine polymorph as lizardite, in agreement with the reported aqueous alteration history of Ryugu. Furthermore, we have mapped the d-spacings of smectite and observed a broad distribution of values, ranging from 1 to 2 nm, with an average d-spacing of 1.24 nm, indicating significant heterogeneity within the sample. Such d-spacing variability could be the result of either the presence of organic matter trapped in the interlayers or the influence of various geochemical conditions at the submicrometer scale, suggestive of a range of organic compounds and/or changes in smectite crystal chemistry

Exosome-Hijacking Drug Delivery System with Branched Arginine Linker Effectively Deliver Antisense Oligonucleotides into Lung Adenocarcinoma Cells

Exosomes are a type of extracellular vesicles that contain diverse molecules and are present in our body fluids. They play a crucial role in transporting materials and transmitting signals between cells. Currently, there have been numerous reports on the use of exosomes in drug delivery systems (DDS). However, most existing methods for utilizing exosomes in DDS require the isolation and purification of exosomes, which raises concerns about yield and potential damage to the exosomes. Recently, we have developed a novel DDS called “ExomiR-Tracker” that harnesses exosomes without the need for isolation and purification. This system aims to deliver nucleic acid drugs effectively. ExomiR-Tracker consists of an anti-exosome antibody equipped with nona-D-arginines (9 mer) and nucleic acid drugs which have complementary sequence of target microRNA (anti-miR). In this study, we modified ExomiR-Tracker by incorporating branched nona-D-arginines (9 + 9 mer) molecules (referred to as Branch ExomiR-Tracker) and evaluated its efficacy in lung adenocarcinoma cells (A549 cells). The improved complex formation ability and enhanced cellular uptake of anti-miR, demonstrated by our findings, highlight the advantages of incorporating branched oligoarginine peptides into the ExomiR-Tracker platform. These results represent significant progress in revealing the effectiveness of Branch ExomiR-Tracker against adhesive cancer cells, which has not been shown to be effective with the conventional Linear ExomiR-Tracker.Chemical & pharmaceutical bulletin, 71(11), pp.819-823; 202

Effects of a novel variant of the yeast γ-glutamyl kinase Pro1 on its enzymatic activity and sake brewing

Sake is a traditional Japanese alcoholic beverage brewed with the yeast Saccharomyces cerevisiae. Sake taste is affected by sugars, organic acids, and amino acids. We previously isolated mutants resistant to the proline analogue azetidine-2-carboxylate derived from a diploid sake yeast strain. Some of the mutants produced a greater amount of proline in the brewed sake. One of them (strain K-9-AZC) carried a novel mutation in the PRO1 gene encoding the Gln79His variant of the γ-glutamyl kinase Pro1, a key enzyme in proline biosynthesis in S. cerevisiae. This mutation resulted in extreme desensitization to feedback inhibition by proline, leading to proline overproduction. Interestingly, sake brewed with K-9-AZC contained 3.7-fold more proline, but only 25% less succinate than sake brewed with the parent strain. Metabolome analysis suggests that the decrease in succinate was attributable to a lower level of 2-oxoglutarate, which is converted into glutamate. The approach here could be a practical method for breeding of yeast strains involved in the diversity of sake taste