著者
Yosuke Inoue Shuhei Nomura Chihiro Nishiura Ai Hori Kenya Yamamoto Tohru Nakagawa Toru Honda Shuichiro Yamamoto Masafumi Eguchi Takeshi Kochi Toshiaki Miyamoto Hiroko Okazaki Teppei Imai Akiko Nishihara Takayuki Ogasawara Naoko Sasaki Akihiko Uehara Makoto Yamamoto Makiko Shimizu Maki Konishi Isamu Kabe Tetsuya Mizoue Seitaro Dohi
出版者
Japan Epidemiological Association
雑誌
Journal of Epidemiology (ISSN:09175040)
巻号頁・発行日
pp.JE20190332, (Released:2020-07-25)
参考文献数
31
被引用文献数
6

Background: While much effort has focused on quantifying disease burden in occupational health, no study has simultaneously assessed disease burden in terms of mortality and morbidity. We aimed to propose a new comprehensive method of quantifying the disease burden in the workplace.Method: The data were obtained from the Japan Epidemiology Collaboration on Occupational Health (J-ECOH) Study, a large-scale prospective study of approximately 80,000 workers. We defined disease burden in the workplace as the number of working years lost among the working population during a 6-year period (April 2012 to March 2018). We calculated the disease burden according to consequences of health problems (i.e., mortality, sickness absence [SA], and ill-health retirement) and disease category. We also calculated the age-group- (20–39 and 40–59 years old) and sex-specific disease burden.Results: The largest contributors to disease burden in the workplace were mental and behavioural disorders (47.0 person-years lost per 10,000 person-years of working years, i.e., per myriad [proportion]), followed by neoplasms (10.8 per myriad) and diseases of the circulatory system (7.1 per myriad). While mental and behavioural disorders made a greater contribution to SA and ill-health retirement compared to mortality, the latter two disorders were the largest contributors to the disease burden in the workplace due to mortality. The number of working years lost was greater among younger vs. older female participants, whereas the opposite trend was observed in males.Conclusions: Our approach is in contrast to those in previous studies that focused exclusively on mortality or morbidity.
著者
金野 浩二 山本 奬 大谷 哲弘 KINNO Koji YAMAMOTO Susumu OHTANI Tetsuhiro
出版者
岩手大学大学院教育学研究科
雑誌
岩手大学大学院教育学研究科研究年報 = Research Journal of the Iwate University Professional School for Teacher Education (ISSN:2432924X)
巻号頁・発行日
vol.3, pp.147-156, 2019-03-29

本研究の目的は,教師からのほめを認知しにくい子供のほめの受け取り方について検討し,どのような言葉がけをすることがほめを認知するのに効果的であるのかを明らかにすることであった。そこで,小学校4~6年生に対して質問紙調査を行い,ほめを認知しにくい子供を抽出した。そして,抽出した子供への聞き取り調査を行うことで効果的な支援方法について検討するとともに,担任による実践によって支援方法の効果を検証した。これにより,ほめを認知しにくい子供は「具体的なことや場面についてほめられると認知する」「努力したことなど本人が自覚していることをほめられると認知する」ということが明らかになった。そして,この2点を踏まえ,教師が「子供の自覚と教師の評価を一致させてほめる」ことが支援として効果的であることがわかった。
著者
Aya MARUYAMA Tomohiro NAKAYAMA Naoyuki SATO Yoshihiro MIZUTANI Kiyohide FURUYA Tatsuo YAMAMOTO
出版者
The Japanese Society of Hypertension
雑誌
Hypertension Research (ISSN:09169636)
巻号頁・発行日
vol.27, no.12, pp.903-909, 2004 (Released:2005-05-16)
参考文献数
25
被引用文献数
26 26

The pathophysiology of preeclampsia (PE) remains uncertain despite many research efforts. Actual hypotheses seek to explain the vascular damage that characterizes the disease. Recently, it was reported that the mouse disrupted estrogen receptor β (ESR2) gene was associated with abnormal vascular function and hypertension. Moreover, some investigators have reported that subjects with a family history of hypertension have a statistically significant increased risk for PE. Thus, it is thought that the pathophysiology of PE overlaps that for hypertension. The aim of the present study was to investigate the relationships between single nucleotide polymorphisms (SNPs) in the human ESR2 gene and PE in Japanese subjects, and to assess the involvement of a family history of hypertension in these relationships. Based on a database search on the web site of the National Center of Biotechnology Information (NCBI), we chose four SNPs in the human ESR2 gene, and performed an association study in 84 PE patients and 160 age-matched non-PE subjects. The overall distribution in each SNP did not differ significantly between the two groups. However, after dividing the groups into subjects with and without a family history of hypertension, the allelic distribution of one of the SNPs (rs928554) revealed a positive association. Thus, a possible mutation linked to a SNP may prescribe a genetic predisposition for patients with a family history of hypertension in PE. (Hypertens Res 2004; 27: 903-909)
著者
Yoshinori Abe Teiji Yamamoto Tomoko Soeda Tomohiro Kumagai Yoshihiro Tanno Jin Kubo Tetsuya Ishihara Soichi Katayama
出版者
The Japanese Society of Internal Medicine
雑誌
Internal Medicine (ISSN:09182918)
巻号頁・発行日
vol.48, no.13, pp.1135-1141, 2009 (Released:2009-07-01)
参考文献数
35
被引用文献数
36 70

Background Unilateral movement disorders and contralateral neuroimaging abnormalities of the striatum have been sporadically reported as a rare syndrome associated with diabetes mellitus. Despite characteristic imaging findings and clinical manifestations, the mechanism underlying this syndrome is still unclear. Methods Six patients with this syndrome were studied clinically and subjected to MRI neuroimaging; one underwent biopsy of the striatum, and another underwent additional MR spectroscopy at 3.0T and FDG-PET. Results Neuroimaging findings were characterized by a T1-hyperintense unilateral lesion restricted to the striatum, contralateral to the symptomatic limbs. The biopsied striatum contained patchy necrotic tissue, severe thickening of all layers of arterioles, and marked narrowing of vessel lumens. Hyaline degeneration of the arteriolar walls, extravasation of erythrocytes, and prominent capillary proliferation were also notable, together with lymphocytic infiltration and macrophage invasion. In one patient, PET examination revealed decreased accumulation of FDG in the lesion. The MR spectrum for the diseased striatum revealed a decrease in the NAA/Cr ratio (1.35), normal Cho/Cr ratio (1.22), and a peak for myoinositol, while the spectrum on the contralateral site revealed a decrease in the NAA/Cr ratio (1.48), increase in Cho/Cr (1.32), but no peak for myoinositol. Conclusion The constellation of signs and symptoms and neuroimaging characteristics in previous reports and the six additional cases described here with neuropathological data and findings of MR spectroscopy appears unique enough to be termed "diabetic striatopathy." This syndrome appears in poorly controlled diabetics due to obliterative vasculopathy with prominent vascular proliferation, vulnerability to which is restricted to the striatum.
著者
Kazuaki TANAKA Misaki YAMAMOTO-FUKUDA Tatsuya TAKIZAWA Hidekatsu SHIMAKURA Masahiro SAKAGUCHI
出版者
JAPANESE SOCIETY OF VETERINARY SCIENCE
雑誌
Journal of Veterinary Medical Science (ISSN:09167250)
巻号頁・発行日
pp.20-0301, (Released:2020-07-15)
被引用文献数
9

Interleukin-4 (IL4) and interleukin-13 (IL13) are involved in the initial response of T helper 2 lymphocytes through the activation of the IL4 receptor alpha (IL4RA), which is a common receptor chain for these cytokines. In humans, several single-nucleotide polymorphisms (SNPs) identified in the IL4R and in interleukin coding genes were associated with atopic disorders. However, the association between canine IL4R polymorphisms and atopic disorders has not been investigated yet. This study aimed to determine the associations between four non-synonymous SNPs and canine atopic dermatitis (CAD) in shiba inu and miniature dachshund populations. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis were used to genotype four polymorphisms of canine IL4R and IL13 in 34 shiba inu and 19 miniature dachshund patients with CAD, as well as 29 shiba inu and 39 miniature dachshund patients without the condition. Results from miniature dachshunds revealed a potential association between the presence of minor A allele rs24378020 and CAD (odds ratio, 0.10; 95% confidence interval, 0.01–0.85; poriginal=0.0062). This CAD resistance allele led to an amino acid substitution (Arg688Cys) that could impair IL4 and IL13 signaling. In shiba inu patients, rs24378020 was fixed by homozygosity of the major G allele. No association was found between the remaining three evaluated SNPs and CAD. Nevertheless, the study suggests that the IL4R Cys688 variant reduces the risk of CAD in miniature dachshunds.
著者
Shuyi SUN Kyohei MATSUI So TANABE Dung NGUYEN Takamasa KINOSHITA Yojiro YAMAMOTO Hiroshi SHIIGI
出版者
The Japan Society for Analytical Chemistry
雑誌
Analytical Sciences (ISSN:09106340)
巻号頁・発行日
vol.36, no.7, pp.787-789, 2020-07-10 (Released:2020-07-10)
参考文献数
11
被引用文献数
4

In this reported work, we achieved high-throughput, highly sensitive fluorescent analysis using an enzyme-linked immunosorbent assay (ELISA) that employed a metallic nanoparticle (NP)-immobilized 96-well plate. The immobilization of metallic NPs on a 96-well plate effectively amplified fluorescent signals of the assay. The silver (Ag) NP-immobilized plate showed the best fluorescent enhancement effect of all plates immobilized by metal NPs. Our results demonstrate the potential of applying Ag NPs to enhance the efficiency of direct and indirect ELISA by the labeling of targets.
著者
Hitoshi Hamamura Hisashi Adachi Mika Enomoto Ako Fukami Sachiko Nakamura Yume Nohara Nagisa Morikawa Akiko Sakaue Kenta Toyomasu Maki Yamamoto Yoshihiro Fukumoto
出版者
Japan Atherosclerosis Society
雑誌
Journal of Atherosclerosis and Thrombosis (ISSN:13403478)
巻号頁・発行日
pp.56390, (Released:2020-07-04)
参考文献数
38
被引用文献数
16

Aim: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been identified as an important regulator of low-density lipoprotein (LDL) receptor processing. Evolocumab and alirocumab are PCSK9 inhibitors; however, little is known about the association between PCSK9 levels and lipid profiles in a general population. Because PCSK9 inhibitors have LDL-C lowering effects, we investigated whether there is a positive correlation between serum PCSK9 levels and LDL-C or lipoprotein(a) [Lp(a)]. Methods: In Uku town, 674 residents (mean age; 69.2±8.3 years) received health check-ups. The participants underwent a physical examination and blood tests, including PCSK9 and Lp(a). Serum PCSK9 and Lp(a) were measured by ELISA and Latex methods, respectively. HOMA-IR was calculated by fasting plasma glucose×insulin levels/405. Results: The mean (range) of PCSK9 and Lp(a) were 211.2 (49-601) ng/mL and 60 (1-107) mg/dL, respectively. Because of a skewed distribution, the log-transformed values were used. With univariate linear regression analysis, PCSK9 levels were associated with Lp(a) (p=0.028), triglycerides (p<0.001), and HOMA-IR (p<0.001), but not with LDL-C (p=0.138) levels. Multiple stepwise regression analysis revealed that serum PCSK9 levels were independently associated with triglycerides (p<0.001), Lp(a) (p=0.033) and HOMA-IR (p=0.041). Conclusions: PCSK-9 is independently associated with triglycerides, Lp(a) levels, and HOMA-IR, but not LDL-C, in a relatively large general population sample.
著者
Takehiro Wakabayashi Shuji Morisaki Norimitsu Kasai Noritoshi Atsumi Shuichiro Yamamoto
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.136-149, 2020 (Released:2020-02-15)
参考文献数
26

This article proposes a tool supported approach to detect omitted requirements that are not implemented in a corresponding architectural design document using difference sets of words or word senses between a software requirements specification document and a software architectural design document. First, the proposed approach extracts sets of single-words, multi-words, and word senses that appear in a requirements specification document but do not appear in the corresponding design document using a natural language processing tool. Then, an architectural design document inspector validates whether each of the specified document with the single-words, multi-words, or word senses are implemented in the corresponding architectural design document using the sets as guides. Evaluation 1 investigated whether omitted requirements can be detected in design documents using the proposed approach. Evaluation 2 investigated the numbers of words that inspectors need to check for the proposed approach. The result of Evaluation 1 shows that omitted requirements are detected in all three pairs for real requirements specification documents and design documents. The result of Evaluation 2 shows that the numbers of words in the difference sets to those in the requirements specification documents vary from 18 to 83 % for the nine pairs of requirements specification documents and design documents.
著者
Mayumi Yamamoto Ryo Horita Tadahiro Sado Akihiro Nishio
出版者
The Japanese Society of Internal Medicine
雑誌
Internal Medicine (ISSN:09182918)
巻号頁・発行日
vol.59, no.9, pp.1155-1162, 2020-05-01 (Released:2020-05-01)
参考文献数
42
被引用文献数
3

Objective To examine the degree of metabolic abnormalities and their association with the sociodemographic background or mental illness/cognitive disability among homeless men in Nagoya, Japan. Methods We interviewed 106 homeless men (aged 54.2±12.7 years) and measured their metabolic parameters. Mental illness and cognitive disability were diagnosed using the Mini-International Neuropsychiatric Interview and Wechsler Adult Intelligence Scale-III test, respectively. Associations between metabolic abnormalities and the sociodemographic background or mental illness/cognitive disability were analyzed. Results There were significant correlations of liver dysfunction (AST≥35 IU, ALT≥35 IU, γ-GTP≥75 IU), hypertension [systolic/diastolic blood pressure (BP) ≥140/90 mmHg], and dyslipidemia (HDL <40 mg/dL) with the history/duration of homelessness (over 2 times/year) and residence status (living on the streets). Although the mean body mass index (BMI), BP, HbA1c, and LDL in participants living in temporary residences were similar to those obtained from the general population data from National Health Nutrition Survey (NHNS) 2016, the systolic/diastolic BP in those living on the street was significantly higher than in the general population, and the HDL in those living in temporary residences was significantly lower than in those reported in the NHNS 2016 data. In the group with cognitive disability, the ALT, TG, and BMI values were significantly higher and the HDL level significantly lower in those living in temporary residences than in those living on the streets. Conclusion Stressful conditions while living on the streets may exacerbate hypertension and liver dysfunction, and unhealthy food habits when living in a temporary residence may exacerbate low HDL levels. In addition, an inability to self-manage due to cognitive disability may increase the ALT, TG, and BMI values. The provision of homeless people with the skills to sustain independent living conditions and ensure a healthy diet is required.
著者
Hiroki Usuku Eiichiro Yamamoto Fumi Oike Tatsuya Yoshinouchi Kanako Imamura Kenichi Yoshida Daisuke Kanesaki Yasuhiro Toma Ayako Tomita Yuji Ogata Seiki Matsumoto Yoshio Iwayama Tomoko Sassa Shinji Tanaka Yoko Fukuyoshi Tamami Matsumoto Eiichiro Tanaka Hiroyuki Shono Kazuhiro Nishigami Kenichi Tsujita Hirotaka Matsui
出版者
The Japanese Circulation Society
雑誌
Circulation Reports (ISSN:24340790)
巻号頁・発行日
vol.2, no.6, pp.297-305, 2020-06-10 (Released:2020-06-10)
参考文献数
17
被引用文献数
3

Background:There are few reports on current awareness and status of transthoracic echocardiography (TTE), including the actual performance rate according to echocardiographic guidelines, in a specific area or region.Methods and Results:This cross-sectional survey study was conducted in Kumamoto Prefecture from October 2018 to March 2019. There are 366 medical institutions advocating cardiology in Kumamoto Prefecture. Of these, 259 (101 hospitals and 158 clinics) returned questionnaires regarding TTE. In all, 150,570 TTEs were performed in 2017. Of these, 132,771 (88%) were performed in hospitals and 17,799 (12%) were performed in clinics. Physicians performed only 5% of TTEs, whereas sonographers performed 86%. Although the modified Simpson method was performed in 90% of hospitals, 3-dimensional echocardiography was performed in only 2% of hospitals. In addition, the left atrial volume index was not examined in approximately 60% of hospitals, and the mean E/E′ ratio was not examined in 80% of hospitals. Multivariable logistic regression analysis revealed that having a Fellow of the Japan Society of Ultrasonic in Medicine was significantly and independently associated with guideline-oriented TTE (odds ratio 9.43; 95% confidence interval 1.22–72.71, P<0.05).Conclusions:The rate of echocardiographic measurements performed according to echocardiographic guidelines is exceptionally low in Kumamoto Prefecture. Sufficient dissemination of echocardiographic guidelines may be important in improving this rate.
著者
Hideo Matsumura Katsunori Kojima Shigeru Mio Takashi Yamamoto Akihisa Kodaira Hiroyasu Koizumi
出版者
Nihon University School of Dentistry
雑誌
Journal of Oral Science (ISSN:13434934)
巻号頁・発行日
pp.19-0005, (Released:2020-05-15)
参考文献数
16
被引用文献数
5

The purpose of the current study was to synthesize a methacrylate monomer with a thiohydantoin structure. In a flask, (2-thiohydantoin-4-yl) propionic acid, 10-hyroxydecyl methacrylate, 4-dimethylaminopyridine, and tetrahydrofuran (THF) were placed in a nitrogen atmosphere. A THF solution of N,N’-dicyclohexylcarbodiimide was added and stirred at room temperature. Ethyl acetate and n-hexane were then added to the reaction mixture. The reacted slurry was purified by chromatography with silica gel and hexane-ethyl acetate gradient elution solvent. The structure of the compound was assigned with proton nuclear magnetic resonance spectrum analysis, infrared spectroscopy, and high-resolution mass spectral analysis. The colorless viscous liquid obtained in yield of 49% was characterized as 10-methacryloyloxydecyl-(2-thiohydantoin-4-yl)propionate (MDTHP) or 10-((3-(5-oxo-2-thioxysoimidazolidin-4-yl)propanoyl)oxy)decyl methacrylate (2-THPDM). The MDTHP was soluble to acetone, isopropanol, and methyl methacrylate up to 2.6% or more. This compound could be potentially applicable as a functional monomer for bonding metals and alloys.
著者
Nahoko Nishibori Asami Kuroda Osamu Yamada Nami Goto-Yamamoto
出版者
Japanese Society for Food Science and Technology
雑誌
Food Science and Technology Research (ISSN:13446606)
巻号頁・発行日
vol.23, no.2, pp.241-248, 2017 (Released:2017-05-27)
参考文献数
19
被引用文献数
9

Dimethyl trisulfide (DMTS) develops in wine during storage, creating an unpleasant aroma. However, the mechanisms of DMTS formation during the wine-making process are poorly understood. We attempted to identify the factors that affect DMTS development during storage. We found that the death of yeast cells, followed by the leakage of their cell contents into the must, enhanced DMTS formation, but this effect varied between grape cultivars. Oxidation of the must and insufficient clarification of the grape juice can also lead to DMTS development during storage. However, DMTS-P1 and methanethiol, precursors of DMTS in other beverages, contributed little to DMTS formation in wine. When synthetic grape must was fermented instead of grape juice, less DMTS developed, despite most yeast cells having died. These findings indicate that unknown compounds contained in grape juice are involved in DMTS formation and that the key compounds involved in DMTS formation in wine originate from grapes.
著者
山本 奬 佐藤 和生 有谷 保 板井 直之 川原 恵理子 三浦 健 若松 優子 YAMAMOTO Susumu SATO Kazuo ARIYA Tamotsu ITAI Naoyuki KAWAHARA Eriko MIURA Ken WAKAMATSU Yuko
出版者
岩手大学大学院教育学研究科
雑誌
岩手大学大学院教育学研究科研究年報 = Research Journal of the Iwate University Professional School for Teacher Education (ISSN:2432924X)
巻号頁・発行日
no.4, pp.223-236, 2020-03-31

本研究の目的は,自殺予防教育の一環として,ソーシャルスキルトレーニングの考え方を参考に「援助要請の仕方・受け止め方」の心理教育プログラムを作成し,小学校3年生から中学校2年生までの児童生徒に実施し,その成果を検証することであった。作成したプログラムについて,援助要請の仕方・その受け止め方共に,当初の自信による適用の禁忌はないことが確認された。援助要請の仕方・その受け止め方の自信の向上については,いずれの学年においてもその効果が認められ,特に小学校中学年において顕著であった。困り事・悩み事の対処姿勢については,中学生と小学校高学年において,肯定的変化が認められた。
著者
Koichi HARAGUCHI Mineshi SAKAMOTO Akito MATSUYAMA Megumi YAMAMOTO Dang T. HUNG Hiromitsu NAGASAKA Keisuke UCHIDA Yasunori ITO Hitoshi KODAMATANI Milena HORVAT Hing M. CHAN Matthew RAND Ciprian M. CIRTIU Byoung-Gwon KIM Flemming NIELSEN Akane YAMAKAWA Nikolay MASHYANOV Nikolai PANICHEV Elena PANOVA Tomoaki WATANABE Naoki KANEKO Jun YOSHINAGA Ranny F. HERWATI Alfrida E. SUOTH Hirokatsu AKAGI
出版者
The Japan Society for Analytical Chemistry
雑誌
Analytical Sciences (ISSN:09106340)
巻号頁・発行日
vol.36, no.5, pp.561-567, 2020-05-10 (Released:2020-05-10)
参考文献数
28
被引用文献数
5

A certified reference material, NIMD-01, was developed for the analysis of mercury speciation in human hair. We collected the hair of Vietnamese males from a barbershop in Hanoi in 2016 and prepared 1200 bottles containing 3 g of sieved and blended hair powder. The certified value was given on a dry-mass basis, with the moisture content obtained by drying at 85°C for 4 h. Certified values with the expanded uncertainties (coverage factor, k = 2) were as follows: methylmercury, 0.634 ± 0.071 mg kg−1 as mercury; total mercury, 0.794 ± 0.050 mg kg−1; copper, 12.8 ± 1.4 mg kg−1; zinc, 234 ± 29 mg kg−1; selenium, 1.52 ± 0.29 mg kg−1. An indicative arsenic concentration of 0.17 ± 0.03 mg kg−1 was measured. Extended uncertainties were estimated by sample homogeneity, long- and short-term stabilities, and a characterization from measurements made by collaborating laboratories.
著者
Junkichi Kanda Megumi Furukawa Nobuo Izumo Taketoshi Shimakura Noriaki Yamamoto Hideaki E. Takahashi Hiroyuki Wakabayashi
出版者
International Research and Cooperation Association for Bio & Socio-Sciences Advancement
雑誌
Drug Discoveries & Therapeutics (ISSN:18817831)
巻号頁・発行日
vol.14, no.2, pp.77-83, 2020-04-30 (Released:2020-05-06)
参考文献数
39

Tacrolimus, a calcineurin inhibitor, affects bone metabolism and increases the risk of fracture due to marked bone loss. Bisphosphonates increase the bone mineral density (BMD) in osteoporosis patients. Menatetrenone has less positive effects on BMD but reduces the risk of fracture by improving bone quality. In this study, we investigated the effectiveness of the combined administration of risedronate and menatetrenone against bone loss induced by tacrolimus. Wistar rats were divided into four groups: [1] control, [2] tacrolimus at 1.5 mg/kg, [3] tacrolimus + risedronate at 1.0 mg/kg, and [4] tacrolimus + risedronate + menatetrenone at 20 mg/kg. After the drugs were administered for 4 weeks, bone histomorphometric analysis was performed and bone strength was evaluated using a three point bending method. BMD was measured using quantitative computed tomography. Tacrolimus significantly reduced the BMD and strength properties of the lower limb bones. These tacrolimusinduced decreases were suppressed by risedronate treatment. The combined administration of risedronate and menatetrenone more significantly improved bone strength properties than risedronate alone. Bone histomorphometric analysis revealed a significant increase in bone resorption with tacrolimus. Risedronate alone significantly suppressed the tacrolimus-induced increase in bone resorption but simultaneously reduced bone formation. On the other hand, the combined administration of risedronate and menatetrenone suppressed the tacrolimus-induced increase in bone resorption, in addition to the significant risedronate-induced decrease in bone formation. This study suggests that the combined administration of risedronate and menatetrenone improves bone strength in tacrolimus-treated rats by preventing and ameliorating the risedronate-induced suppression of bone formation.
著者
Haruki Yamamoto Hiroko Kojima-Ando Kaori Ohki Yuichi Fujita
出版者
Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
雑誌
The Journal of General and Applied Microbiology (ISSN:00221260)
巻号頁・発行日
pp.2020.01.009, (Released:2020-04-02)
参考文献数
62
被引用文献数
8

Protochlorophyllide (Pchlide) reduction is the penultimate step of chlorophyll (Chl) biosynthesis, and is catalyzed by two evolutionarily unrelated enzymes: dark-operative Pchlide oxidoreductase (DPOR) and light-dependent Pchlide oxidoreductase (LPOR). Because LPOR is the sole Pchlide reductase in angiosperms, dark-grown seedlings of angiosperms become etiolated. LPOR exists as a ternary complex of Pchlide-NADPH-LPOR to form paracrystalline prolamellar bodies (PLBs) in etioplasts. Because LPOR is distributed ubiquitously across oxygenic phototrophs including cyanobacteria, it would be important to determine whether cyanobacterial LPOR has the ability to form PLBs. We isolated a DPOR-less transformant ΔchlL/LPORox, carrying a plasmid to overexpress cyanobacterial LPOR in the cyanobacterium Leptolyngbya boryana. The transformant did not produce Chl in the dark and became etiolated with an accumulation of Pchlide and LPOR. Novel PLB-like ultrastructures were observed in etiolated cells, which disappeared during the early stage of the light-dependent greening process. However, the rate of Chl production in the greening process of ΔchlL/LPORox was almost the same as that observed in the control cells, which carried an empty vector. An in vitro LPOR assay of extracts of dark-grown ΔchlL/LPORox cells suggested that the PLB-like structures are deficient in NADPH. Low-temperature fluorescence emission spectra of membrane fractions of the etiolated cells indicated the absence of the photoactive form of Pchlide, which was consistent with the inefficiency of the greening process. Cyanobacterial LPOR exhibited an intrinsic ability to form PLB-like ultrastructures in the presence of the co-accumulation of Pchlide; however, the PLB-like structure differed from the authentic PLB regarding NADPH deficiency.