41 research outputs found
Morphological Changes with growth in Liza cCarinata (Valenciennes) egg, larva and juvenile as distinguished from those of Liza Haematocheila (ScWegel)
The morphological changes in the egg, larval and juvenile stages of Liza carinata with growth were investigated
in reared and wild specimens. L. carinata could be distinguished from L. haematocheila which is likely to spawn
concurrently in time and space in the egg, larva, and juvenile stages. The eggs hatch within 45-102 h after fertilization
in water of15-21 °C, corresponding to the temperature in the spawning ground. A newly-hatched larva averages
2.1 mm in total length. The anlage of the caudal fin appears in the larva of around 3.4 mm and the juvenile
stage is attained at a length of 8.9 mm. L. haematocheila is distinguished fly its larger size in the egg and larval
stages. The melanophores located on the top of the head and the rear end of the tail in L. carinata may also serve
as distinguishing marks in the larval stages. The longer extension of the mid-lateral melanophore row in L. carinata
distinguishes them in the juvenile stage. The characteristic dorsal ridge in L. carinata (which does not occur
in L. haematocheila) appears after a total length of 30mm is reached
有明海産コノシロの増殖生態-2 : 成熟過程
In order to know the process of the maturation of a shad, Konosirus punctatus, observations and measurements of the ovaries and ovarian eggs were done, and the following results were obtained. Eggs of the yolk globule stage and younger stages were observed together in an ovary during the spawning season. In some of such ovaries there were eggs older than yolk globule stage. In egg-diameter composition of an ovary taken in the spawning season, 1~4 modes were recognized, showing the existence of some batches in an ovary. The largest mode (the largest batch) in ovarian egg diameter composition is formed in more than 0.4mm. The largest batch passes the stage where the mode is in 0.41~0.70mm in 2 days of more. This batch passes the stage of 0.71~4.00mm in about half a day from 3a.m. to 3p.m., and becomes ripe. The spawning is carried out in the time from 3p.m. to midnight. Individual shad spawns twice or more in a spawning season of one month or one month and half. Spawning interval of the individual is estimated to be 3 days or more.コノシロKonosirus punctatusの成熟過程を明らかにするため,卵巣と卵巣卵の観察と測定を行った。産卵期の卵巣には卵黄球期の卵とそれより若い卵が混在する。そのような卵巣の中に,卵黄球期よりさらに発達の進んだ卵が混在するものもある。産卵期には,卵巣卵卵径の頻度分布に1~4個のモードが認められ,1卵巣中に数個の卵群が存在することを示している。卵径頻度分布中の最大のモード(最も発達した卵群)は0.4mm以上で形成される。その卵群はモードが0.41~0.70mmにある発達段階を2日かそれ以上で,0.71~1.00mmを約半日,およそ午前3時から午後3時までに経過し,完熟となる。産卵は午後3時ごろから夜中にかけて行われる。1個体はひと月またはひと月半にわたる産卵期に2回またはそれ以上の産卵を行う。個体の産卵間隔は3日またはそれ以上である
有明海産コノシロの増殖生態-1 : 分布と産卵群の魚体特性
In order to know the process of the maturation of a shad, Konosirus punctatus, observations and measurements of the ovaries and ovarian eggs were done, and the following results were obtained. Eggs of the yolk globule stage and younger stages were observed together in an ovary during the spawning season. In some of such ovaries there were eggs older than yolk globule stage. In egg-diameter composition of an ovary taken in the spawning season, 1~4 modes were recognized, showing the existence of some batches in an ovary. The largest mode (the largest batch) in ovarian egg diameter composition is formed in more than 0.4mm. The largest batch passes the stage where the mode is in 0.41~0.70mm in 2 days of more. This batch passes the stage of 0.71~4.00mm in about half a day from 3 a.m. to 3 p.m., and becomes ripe. The spawning is carried out in the time from 3 p.m. to midnight. Individual shad spawns twice or more in a spawning season of one month or one month and half. Spawning interval of the individual is estimated to be 3 days or more.有明海産コノシロKonosirus punctatusの増殖生態を明らかにする目的で,漁獲統計によって魚群の移動を調べ,魚体測定によって成長と肥満度,成熟度などの魚体の状態を明らかにした。本種は,冬は有明海湾口部に近い,比較的外洋的な水域に分布し,春から秋は主に湾奥部浅海に分布する。1974年の調査結果から,平均体長は生後満1年で148mm,2年で189mm,3年で約210mmと推定した。1,2年魚が漁獲の大多数を占め,4年以上のものは認められなかった。全ての年令群が産卵に加わる。生殖腺重量指数の時期的な変化から,1974年の産卵盛期は4,5月と推定した。1年魚は2・3年魚より産卵期がわずかにおそい。肥満度に,生殖腺重量指数の変化に対応した変化が認められた
Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2
The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16×12∘ and a spatial resolution of 0.05∘ per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission
Highly porous nature of a primitive asteroid revealed by thermal imaging
Carbonaceous (C-type) asteroids are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth’s atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR) onboard the spacecraft Hayabusa2, indicating that the asteroid’s boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m−2 s−0.5 K−1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect. We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites. These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies.Additional co-authors: Tsuneo Matsunaga, Takeshi Imamura, Takehiko Wada, Sunao Hasegawa, Jörn Helbert, Thomas G. Müller, Jens Biele, Matthias Grott, Maximilian Hamm, Marco Delbo, Naru Hirata, Naoyuki Hirata, Yukio Yamamoto, Seiji Sugita, Noriyuki Namiki, Kohei Kitazato, Masahiko Arakawa, Shogo Tachibana, Hitoshi Ikeda, Masateru Ishiguro, Koji Wada, Chikatoshi Honda, Rie Honda, Yoshiaki Ishihara, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Akira Miura, Tomokatsu Morota, Hirotomo Noda, Rina Noguchi, Kazunori Ogawa, Kei Shirai, Eri Tatsumi, Hikaru Yabuta, Yasuhiro Yokota, Manabu Yamada, Masanao Abe, Masahiko Hayakawa, Takahiro Iwata, Masanobu Ozaki, Hajime Yano, Satoshi Hosoda, Osamu Mori, Hirotaka Sawada, Takanobu Shimada, Hiroshi Takeuchi, Ryudo Tsukizaki, Atsushi Fujii, Chikako Hirose, Shota Kikuchi, Yuya Mimasu, Naoko Ogawa, Go Ono, Tadateru Takahashi, Yuto Takei, Tomohiro Yamaguchi, Kent Yoshikawa, Fuyuto Terui, Takanao Saiki, Satoru Nakazawa, Makoto Yoshikawa, Seiichiro Watanabe & Yuichi Tsud
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target