Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

In haemoglobin (consisting of four globular myoglobin-like subunits), the change from the low-spin (LS) hexacoordinated haem to the high spin (HS) pentacoordinated domed form upon ligand detachment and the reverse process upon ligand binding, represent the transition states that ultimately drive the respiratory function. Visible-ultraviolet light has long been used to mimic the ligand release from the haem by photodissociation, while its recombination was monitored using time-resolved infrared to ultraviolet spectroscopic tools. However, these are neither element- nor spin-sensitive. Here we investigate the transition state in the case of Myoglobin-NO (MbNO) using femtosecond Fe Kalpha and Kbeta non-resonant X-ray emission spectroscopy (XES) at an X-ray free-electron laser upon photolysis of the Fe-NO bond. We find that the photoinduced change from the LS (S = 1/2) MbNO to the HS (S = 2) deoxy-myoglobin (deoxyMb) haem occurs in ca. 800 fs, and that it proceeds via an intermediate (S = 1) spin state. The XES observables also show that upon NO recombination to deoxyMb, the return to the planar MbNO ground state is an electronic relaxation from HS to LS taking place in ca. 30 ps. Thus, the entire ligand dissociation-recombination cycle in MbNO is a spin cross-over followed by a reverse spin cross-over process

Femtosecond time-resolved X-ray absorption spectroscopy of anatase TiO2 nanoparticles using XFEL

光触媒ナノ粒子における光照射後10兆分の1秒での電子の動きをX線自由電子レーザーで観測. 京都大学プレスリリース. 2017-07-06.The charge-carrier dynamics of anatase TiO2 nanoparticles in an aqueous solution were studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser in combination with a synchronized ultraviolet femtosecond laser (268 nm). Using an arrival time monitor for the X-ray pulses, we obtained a temporal resolution of 170 fs. The transient X-ray absorption spectra revealed an ultrafast Ti K-edge shift and a subsequent growth of a pre-edge structure. The edge shift occurred in ca. 100 fs and is ascribed to reduction of Ti by localization of generated conduction band electrons into shallow traps of self-trapped polarons or deep traps at penta-coordinate Ti sites. Growth of the pre-edge feature and reduction of the above-edge peak intensity occur with similar time constants of 300–400 fs, which we assign to the structural distortion dynamics near the surface

Clinical Characteristics of Acute Exacerbations of Idiopathic Pulmonary Fibrosis and Involvement of Viral, Mycoplasma pneumoniae, and Chlamydophila pneumoniae Infections

Background and Objective:To clarify the clinical characteristics of acute exacerbation of idiopathic pulmonaryfibrosis (IPF) and the involvement of infections with pathogenic microorganisms and viruses inacute exacerbation.Methods:During the 12 years from 2000 through 2011, we studied 50 patients who were admitted andreceived treatment for acute exacerbation of IPF in our department. Demographic characteristics, imagingfindings, laboratory findings, changes in antibody titers against bacteria, Mycoplasma pneumoniae, Chlamydophilapneumoniae, and known viruses, and outcomes were studied.Results:Among the 50 patients with acute exacerbation of IPF( 41 men and 9 women) 29 patients died(mortality rate, 58.0%). Computed tomography showed subpleural peripheral ground-glass opacities( GGO)in 5 patients, multiple patchy GGO in 19, and diffuse GGO in 26. Only the PaO2/FiO2 ratio was significantlylower in the non-survivors compared with survivors. Three patients had high titers of IgM antibodiesagainst C. pneumoniae, but acute infection was ruled out by the changes in IgA and IgG antibodies in pairedserum samples. Antibody titers against known viruses significantly increased in 2 patients( respiratory syncytialvirus in 1 and adenovirus 11 in 1). In acute-phase serum samples, 7 patients had increased antibodytiters against parainfluenza virus 3, resulted in no significant change in paired serum samples.Conclusions:Our results suggest that known pathogens do not play a role in acute exacerbation of IPF.The outcomes of IPF remain poor, and the elucidation of the causes and pathological features of acute exacerbationof IPF, including the identification of unknown pathogens, is awaited

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

ドッキョウ イカ ダイガク ビョウイン コキュウキ・アレルギー ナイカ ニオケル HIVカンセン カンジャ ノ カイセキ : トクニ ニューモシスチス ハイエン ノ ガッペイ レイ ニ ツイテ

獨協医科大学病院呼吸器・アレルギー内科を受診したHIV感染者を解析し,わが国および栃木県のHIV 感染者との比較検討を行った.対象は,2002年7月より2009年6月までの間,当科に受診歴のある34名(男27名,女7名,日本人29名,外国人5名),平均年齢は44.2歳(29歳〜67歳).男性の感染理由は,異性間(風俗,不特定)40.7%,同性間37.0%,女性はパートナーからの感染が57.1 %であった.64.7%がAIDS 発症によりHIV感染が判明し,HIV感染判明時の精査では79.4%がAIDSを発症しており,全症例の55.9%にニューモシスチス肺炎の合併を認めた.治療開始が推奨されているCD4陽性細胞低値(350/m l以下)は,97.1%の症例に認めた.以上の結果より,感染理由や年齢層については,全国の平均と同様な傾向を認めた.全国的には,HIV感染判明者の約7割がAIDS 発病前のキャリアの状態でHIV 感染が判明し,栃木県でも同様の傾向である.しかし,当科では大多数がAIDS 発症後およびAIDS 発症直前の低免疫状態でHIV 感染が判明しており,早期発見および早期介入が課題と考えられた.To be clear the clinical characteristics in Tochigi, we analyzedpatients with HIV infection in our department. Patientswith HIV infection between July 2002 and June 2009were 34 subjects (Man:Woman=27:7, Japanese:Foreigner=29:5), and mean age was 44.2 years old. In reasonof HIV infection for men, men who were infected by sexualintercourse with indefinite women were 40.7 % and menwho were infected by sexual intercourse with men were37.0 %. Women who were infected by their partners were57.1 %. 64.7 % of patients were recognized HIV infection byshowing AIDS. 79.4% of patients already had complicationsindicating AIDS, when they came to our hospital, and 55.9% of patients had pneumocystis jiroveci pneumonia. In 97.1% of patients, the number of CD4 positive cells were under350/m l. In conclusion, around 70 % of patients were recognizedHIV infection before they become AIDS in Japan. But,a large majority of patients in our department were withbecoming AIDS or just before AIDS. We need to developthe system of early intervention for HIV infection