通気量と塩分勾配がオニオコゼ仔稚魚の生残と成長に与える影響

We examined the effects of a flow field in the rearing tank exhibited by different aeration rate and salinity gradient on the larviculture of the devil stinger Inimicus japonicus. Two different rearing experiments using 1 kl rearing tanks were conducted from hatching (day 0) to settlement. In the Experiment 1, fish were reared until day 21 in 5 different aeration rates (0-1200 ml/min). There was a significant and positive relationship between survival andaeration rate, and fish survival became stable at an aeration rate of more than 300 ml/min. In Experiment 2, the salinity gradient in a rearing tank was formed by pumping brackish water (22 ppt) from the surface and seawater (34 ppt) from the bottom at the same time. Control rearing tanks (34 ppt) were aerated at 300 ml/min and fish were reared until day 23. Growth and development was synchronized in the salinity gradient tanks with little standard deviation, although average survival at settlement in the salinity gradient tank (47.3 %) was lower than the aeration tank (68.2 %). The optimal aeration rate for devil stinger larviculture is stronger than 300 ml/min and introducing a salinity gradient can be a novel approach for enhancing performance of the fish.異なる通気量と塩分勾配がオニオコゼ仔魚飼育に与える影響を調べた。容量1klの円形水槽で2つの飼育実験を孵化仔魚（0日齢）より着底まで実施した。実験1では5つの異なる通気量（0-1200 ml/min）で21日齢までの飼育を行った。その結果，最終日の生残と通気量の間に有意な正の相関が検出され，300ml/min以上の通気量で生残が安定した。実験2では飼育水槽に水面から22pptの汽水，底面から34pptの海水をそれぞれ連続注入することで塩分勾配を形成させ，対照に34ppt海水に300ml/minの通気を施す水槽を設け，23日齢まで飼育した。その結果，塩分勾配水槽で飼育した魚の成長と着底が同調したが，飼育終了時の生残（47.3 %）は対照のそれ（68.2 %）より低い傾向があった。1kl規模でのオニオコゼの仔魚飼育には300ml/min以上の強い通気による水流が必要であることが明らかになり，さらに塩分勾配の飼育水槽への導入により種苗生産に新たな可能性を見いだした

Genomic Profiling of Submucosal-Invasive Gastric Cancer by Array-Based Comparative Genomic Hybridization

Genomic copy number aberrations (CNAs) in gastric cancer have already been extensively characterized by array comparative genomic hybridization (array CGH) analysis. However, involvement of genomic CNAs in the process of submucosal invasion and lymph node metastasis in early gastric cancer is still poorly understood. In this study, to address this issue, we collected a total of 59 tumor samples from 27 patients with submucosal-invasive gastric cancers (SMGC), analyzed their genomic profiles by array CGH, and compared them between paired samples of mucosal (MU) and submucosal (SM) invasion (23 pairs), and SM invasion and lymph node (LN) metastasis (9 pairs). Initially, we hypothesized that acquisition of specific CNA(s) is important for these processes. However, we observed no significant difference in the number of genomic CNAs between paired MU and SM, and between paired SM and LN. Furthermore, we were unable to find any CNAs specifically associated with SM invasion or LN metastasis. Among the 23 cases analyzed, 15 had some similar pattern of genomic profiling between SM and MU. Interestingly, 13 of the 15 cases also showed some differences in genomic profiles. These results suggest that the majority of SMGCs are composed of heterogeneous subpopulations derived from the same clonal origin. Comparison of genomic CNAs between SMGCs with and without LN metastasis revealed that gain of 11q13, 11q14, 11q22, 14q32 and amplification of 17q21 were more frequent in metastatic SMGCs, suggesting that these CNAs are related to LN metastasis of early gastric cancer. In conclusion, our data suggest that generation of genetically distinct subclones, rather than acquisition of specific CNA at MU, is integral to the process of submucosal invasion, and that subclones that acquire gain of 11q13, 11q14, 11q22, 14q32 or amplification of 17q21 are likely to become metastatic

A pristine record of outer Solar System materials from asteroid Ryugu’s returned sample

Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of ~30 °C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition

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

Can Clethra barbinervis Distinguish Nickel and Cobalt in Uptake and Translocation?

Clethra barbinervis Sieb. et Zucc. accumulates Nickel (Ni) and Cobalt (Co) at high concentrations., We hypothesized that C. barbinervis cannot distinguish between Ni and Co because of the similar chemical properties of these two elements. To confirm this hypothesis and understand the role of these elements in C. barbinervis, we conducted a hydroponic split-root experiment using Ni and Co solutions. We found that the bioconcentration factor (BCF; metal concentration of each tissue/metal concentrations of each treatment solution) of Ni and Co did not significantly differ in the roots, but the BCF for Co was higher than that for Ni in the leaves. The leaves of C. barbinervis accumulated Ni or Co at high concentrations. We also found the simultaneous accumulation of Ni and Co by the multiple heavy metal treatments (Ni and Co) at high concentrations similar to those for the single treatments (Ni or Co). Elevated sulfur concentrations occurred in the roots and leaves of Co-treated seedlings but not in Ni. This result indicates that S was related to Co accumulation in the leaves. These results suggest that C. barbinervis distinguishes between Ni and Co during transport and accumulation in the leaves but not during root uptake

通気量と塩分勾配がオニオコゼ仔稚魚の生残と成長に与える影響

We examined the effects of a flow field in the rearing tank exhibited by different aeration rate and salinity gradient on the larviculture of the devil stinger Inimicus japonicus. Two different rearing experiments using 1 kl rearing tanks were conducted from hatching (day 0) to settlement. In the Experiment 1, fish were reared until day 21 in 5 different aeration rates (0-1200 ml/min). There was a significant and positive relationship between survival and aeration rate, and fish survival became stable at an aeration rate of more than 300 ml/min. In Experiment 2, the salinity gradient in a rearing tank was formed by pumping brackish water (22 ppt) from the surface and seawater (34 ppt) from the bottom at the same time. Control rearing tanks (34 ppt) were aerated at 300 ml/min and fish were reared until day 23. Growth and development was synchronized in the salinity gradient tanks with little standard deviation, although average survival at settlement in the salinity gradient tank (47.3 %) was lower than the aeration tank (68.2 %). The optimal aeration rate for devil stinger larviculture is stronger than 300 ml/min and introducing a salinity gradient can be a novel approach for enhancing performance of the fish.異なる通気量と塩分勾配がオニオコゼ仔魚飼育に与える影響を調べた。容量1klの円形水槽で2つの飼育実験を孵化仔魚（0日齢）より着底まで実施した。実験1では5つの異なる通気量（0-1200 ml/min）で21日齢までの飼育を行った。その結果，最終日の生残と通気量の間に有意な正の相関が検出され，300ml/min以上の通気量で生残が安定した。実験2では飼育水槽に水面から22pptの汽水，底面から34pptの海水をそれぞれ連続注入することで塩分勾配を形成させ，対照に34ppt海水に300ml/minの通気を施す水槽を設け，23日齢まで飼育した。その結果，塩分勾配水槽で飼育した魚の成長と着底が同調したが，飼育終了時の生残（47.3 %）は対照のそれ（68.2 %）より低い傾向があった。1kl規模でのオニオコゼの仔魚飼育には300ml/min以上の強い通気による水流が必要であることが明らかになり，さらに塩分勾配の飼育水槽への導入により種苗生産に新たな可能性を見いだした

Varietal differences in the growth responses of rice to an arbuscular mycorrhizal fungus under natural upland conditions

Seedlings of three rice (Oryza sativa L.) varieties (one indica, ARC5955; and two japonica, Nipponbare and Koshihikari) with or without pre-colonization by the arbuscular mycorrhizal fungus Funneliformis mosseae were transplanted into an upland field and grown to maturity. Pre-colonization had no effect on the yield of Nipponbare or Koshihikari. However, pre-colonized ARC5955 exhibited a strong tendency toward increased yield, which was accompanied by increases in the percentage of ripened grain and the 1000-grain weight. The rice roots were also colonized by indigenous arbuscular mycorrhizal fungi in the field, but these had only limited effects on shoot biomass and grain yields. We speculate that F. mosseae may have exhibited priority effects, allowing it to dominate the rice roots. There was no significant difference in the contents of most mineral elements in the shoots of pre-colonized ARC5955 at harvest, indicating that some other factor is responsible for the observed yield increase