Breeding streams of Mayacnephia aguirrei (Diptera : Simuliidae) in Guatemala

金沢大学留学生センター本種の幼虫は山間の標高800∿1400mにある小さな流れで採集された。これらの川では雨期だけに水が流れ, 乾期には干上がった。雨期の初めは水位が不安定で, 時には出水によって幼虫がいなくなった。水位が下がって流れが寸断された時には, 幼虫は水溜りや石の間の湿った場所にいた。本種を含めMayacnephia属の6種の幼虫は中米の高地の小流にのみ棲息する。このうちグァテマラに分布する3種はすべて, 雨期だけに水が流れる川に出現する

グァテマラにおける Simulium ochraceum の分布に関する地質・地形学的研究

金沢大学留学生センターグァテマラのオンコセルカ症流行地で, 主要媒介種であるSimulium ochraceumの発生源の分布を調査し, 地質および地形との関係を検討した。調査面積477(km)^2内で計246本(144.4km)の不断水流が発見もしくは確認され, うち119本(48.4%) 27.8km (19.3%)でS. ochraceumの発生が認められた。S. ochraceum幼虫は主として古い不透水性の岩に分布していた。これに対して新しい火山岩は透水性が高く, 不断水流を保持しないため, S. ochraceumの発生に不適だが, 不透水性岩の上に位置した時, 地下水の供給源として重要になる。沖積地では水流密度が高かったが, これらの水流ではまったくS. ochraceumの発生が見られなかった。第三紀泥流・溶岩地帯はS. ochraceumの発生源を最も多く有し, かつオンコセルカ症流行地とも一致した。この地帯(77(km)^2)にある計1469本の谷セグメントを踏査した結果, 203本(13.8%)が不断水流を持ち, このうち108本(53.2%)がS. ochraceumの発生源となっていた。谷次数が高くなる下流ほど, 谷セグメントが不断水流を持つ率が高くなったが, それらの水流がS. ochraceumを発生させる率は逆に低くなった。S. ochraceumの分布は, 主として源流の湧泉から下流1km以内の谷次数の低い谷セグメントに多く見られた。湧泉は主として海抜900m, 1100m, 1300-1460mの3段階の高度に沿って, ほぼ水平に分布していた。 On-foot surveys were made for the purpose of mapping perennial streams infected with Simulium ochraceum in an endemic area of onchocerciasis in Guatemala. Of 246 perennial streams (144.4km) found in 477(km)^2,119 (48.4%) or 27.8km (19.3%) were found infested with S. ochraceum. S. ochraceum larvae were found mainly from older impermeable rocks such as Tertiary lahars and lavas, arkosic conglomerate and Cretaceous granite. Although recent volcanic rocks have very few perennial streams due to permeability, they are important as water reservoirs for the underlying impermeable rocks. Quarternary alluvium showed high stream density, but no S. ochraceum larva was found from these streams, due probably to small channel slope. The area with Tertiary lahars and lavas is the most important bed of ochraceum-breeding streams, which roughly coincides with the onchocerciasis endemic area. Of total 1469 channel segments in this area, only 203 (13.8%) had perennial streams, of which 108 (53.2%) were infested with S. ochraceum. With increment of the channel order, the raito of channel segments with perennial streams increased, while, on the contrary, the ratio of perennial streams with S. ochraceum larvae decreased. No S. ochraceum larva was found in the fourth and fifth order channels. S. ochraceum larvae were found mainly in the uppermost part of the stream network, immediately below headsprings. The headsprings were found arranged nearly horizontally on the elevations 900m, 1100m and 1300-1460m above sea level

Notes on the age determination, ovariole changes and gonotrophic cycle of Simulium ochraceum in Guatemala

金沢大学留学生センター室内および野外個体の解剖観察をもとに, S. ochraceumの羽化から吸血までの最短期間を2日, 吸血から産卵までを5日, 産卵後まもなく2回目の吸血をすると仮定すると, 吸血-産卵-吸血(gonotrophic cycle)の最短期間は5日と考えられた。調査4地点(1977年10月∿12月)の平均産卵経験率はS. ochraceum 48.7%, S. callidum 46.9%, S. metallicum 41.2%, S. mexicanum 38.9%であった。産卵経験率およびsac-like relic率は日変化を示し, 午後に高い傾向を示した。以上のことからS. ochraceumの日生存率は0.866と計算され, 羽化後1回目の吸血でO. volvulusのMf.を取り込んだとして, これが感染型に発育し, 伝播可能になる吸血後9日目の生存率は27.3%と推定された。 Of the S. ochraceum in Guatemala, the shortest duration from emergence to blood-feeding, from blood-feeding to oviposition (both at 22℃) and from oviposition to next blood-feeding (under the field condition) were presumed to be 2 days, 5 days and 0 day, respectively. One gonotrophic cycle of this species was to be 5 days in the shortest case. The average parous rate observed in the blackflies collected at four locations from October to December, 1977 were 48.7% for S. ochraceum, 41.2% for S. metallicum, 46.9% for S. callidum and 38.9% for S. mexicanum. The parous rate showed diurnal change, those of which captured in the afternoon being somewhat higher. The survival rate of S. ochraceum for 9 days after blood-feeding when this species become infective, was estimated at 27.3%

Signature of strange dibaryon in kaon-induced reaction

We examine how the signature of the strange-dibaryon resonances in the barKNN-piSigmaN system shows up in the scattering amplitude on the physical real energy axis within the framework of Alt-Grassberger-Sandhas (AGS) equations. The so-called point method is applied to handle the three-body unitarity cut in the amplitudes. We also discuss the possibility that the strange-dibaryon production reactions can be used for discriminating between existing models of the two-body barKN-piSigma system with Lambda(1405).Comment: 4 pages, 6 figures, talk given at The Fifth Asia-Pacific Conference on Few-Body Problems in Physics 2011 (APFB2011), held in Seoul, Korea, August 22-26, 201

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

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