Publications by authors named "Hiroyuki Koyama"

145 Publications

STOP1 regulatory system: Centered on multiple stress tolerance and cellular nutrient management.

Mol Plant 2021 Aug 23. Epub 2021 Aug 23.

Applied Biological Sciences, Gifu University, 501-1193 Gifu, Japan.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molp.2021.08.014DOI Listing
August 2021

Synergistic and antagonistic pleiotropy of STOP1 in stress tolerance.

Trends Plant Sci 2021 10 9;26(10):1014-1022. Epub 2021 Jul 9.

Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. Electronic address:

SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) is a master transcription factor (TF) that regulates genes encoding proteins critical for cellular pH homeostasis. STOP1 also causes pleiotropic effects in both roots and shoots associated with various stress tolerances. STOP1-regulated genes in roots synergistically confer tolerance to coexisting stress factors in acid soil, and root-architecture remodeling for superior phosphorus acquisition. Additionally, STOP1 confers salt tolerance to roots under low-potassium conditions. By contrast, STOP1 antagonistically functions in shoots to promote hypoxia tolerance but to suppress drought tolerance. In this review, we discuss how these synergetic- and antagonistic-pleiotropic effects indicate that STOP1 is a central hub of stress regulation and that the harmonization of STOP1-regulated traits is essential for plant adaptation to various environments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tplants.2021.06.011DOI Listing
October 2021

The biotechnological importance of the plant-specific NAC transcription factor family in crop improvement.

J Plant Res 2021 May 22;134(3):475-495. Epub 2021 Feb 22.

Department of Biotechnology, UIET, Punjab University, Chandigarh, India.

Climate change, malnutrition, and food insecurity are the inevitable challenges being faced by the agriculture sector today. Plants are susceptible to extreme temperatures during the crucial phases of flowering and seed development, and elevated carbon levels also lead to yield losses. Productivity is also affected by floods and droughts. Therefore, increasing plant yield and stress tolerance are the priorities to be met through novel biotechnological interventions. The contributions of NAC genes towards enhancing plant survivability under stress is well known. Here we focus on the potential of NAC genes in the regulation of abiotic stress tolerance, secondary cell wall synthesis, lateral root development, yield potential, seed size and biomass, ROS signaling, leaf senescence, and programmed cell death. Once naturally tolerant candidate NAC genes have been identified, and the nature of their association with growth and fitness against multi-environmental stresses has been determined, they can be exploited for building inherent tolerance in future crops via transgenic technologies. An update on the latest developments is provided in this review, which summarizes the current understanding of the roles of NAC in the establishment of various stress-adaptive mechanisms in model and food crop plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10265-021-01270-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106581PMC
May 2021

High affinity promoter binding of STOP1 is essential for early expression of novel aluminum-induced resistance genes GDH1 and GDH2 in Arabidopsis.

J Exp Bot 2021 03;72(7):2769-2789

Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.

Malate efflux from roots, which is regulated by the transcription factor STOP1 (SENSITIVE-TO-PROTON-RHIZOTOXICITY1) and mediates aluminum-induced expression of ALUMINUM-ACTIVATED-MALATE-TRANSPORTER1 (AtALMT1), is critical for aluminum resistance in Arabidopsis thaliana. Several studies showed that AtALMT1 expression in roots is rapidly observed in response to aluminum; this early induction is an important mechanism to immediately protect roots from aluminum toxicity. Identifying the molecular mechanisms that underlie rapid aluminum resistance responses should lead to a better understanding of plant aluminum sensing and signal transduction mechanisms. In this study, we observed that GFP-tagged STOP1 proteins accumulated in the nucleus soon after aluminum treatment. The rapid aluminum-induced STOP1-nuclear localization and AtALMT1 induction were detected in the presence of a protein synthesis inhibitor, suggesting that post-translational regulation is involved in these events. STOP1 also regulated rapid aluminum-induced expression for other genes that carry a functional/high-affinity STOP1-binding site in their promoter, including STOP2, GLUTAMATE-DEHYDROGENASE1 and 2 (GDH1 and 2). However STOP1 did not regulate Al resistance genes which have no functional STOP1-binding site such as ALUMINUM-SENSITIVE3, suggesting that the binding of STOP1 in the promoter is essential for early induction. Finally, we report that GDH1 and 2 which are targets of STOP1, are novel aluminum-resistance genes in Arabidopsis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/erab031DOI Listing
March 2021

Expression genome-wide association study identifies that phosphatidylinositol-derived signalling regulates ALUMINIUM SENSITIVE3 expression under aluminium stress in the shoots of Arabidopsis thaliana.

Plant Sci 2021 Jan 14;302:110711. Epub 2020 Oct 14.

Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan. Electronic address:

To identify unknown regulatory mechanisms leading to aluminium (Al)-induction of the Al tolerance gene ALS3, we conducted an expression genome-wide association study (eGWAS) for ALS3 in the shoots of 95 Arabidopsis thaliana accessions in the presence of Al. The eGWAS was conducted using a mixed linear model with 145,940 genome-wide single nucleotide polymorphisms (SNPs) and the association results were validated using reverse genetics. We found that many SNPs from the eGWAS were associated with genes related to phosphatidylinositol metabolism as well as stress signal transduction, including Casignals, inter-connected in a co-expression network. Of these, PLC9, CDPK32, ANAC071, DIR1, and a hypothetical protein (AT4G10470) possessed amino acid sequence/ gene expression level polymorphisms that were significantly associated with ALS3 expression level variation. Furthermore, T-DNA insertion mutants of PLC9, CDPK32, and ANAC071 suppressed shoot ALS3 expression in the presence of Al. This study clarified the regulatory mechanisms of ALS3 expression in the shoot and provided genetic evidence of the involvement of phosphatidylinositol-derived signal transduction under Al stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plantsci.2020.110711DOI Listing
January 2021

Comparative RNA-Seq analysis of the root revealed transcriptional regulation system for aluminum tolerance in contrasting indica rice of North East India.

Protoplasma 2021 May 13;258(3):517-528. Epub 2020 Nov 13.

Plant Molecular Biotechnology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, Assam, 788011, India.

Expression pattern of aluminum (Al) tolerance genes is one of the major determinants of Al avoidance/tolerance within plant cultivars. We have performed transcriptome analysis of two contrasting (Al-tolerant, Disang; Al-sensitive, Joymati) cultivars of India's North Eastern region, an indica rice diversity hotspot, on exposure to excess Al treatment in acidic condition. Co-expression analysis and SNPs enrichment analysis proposed the role of both trans-acting and cis-acting polymorphisms in Al signaling in the Al-tolerant cultivar. We proposed ten major genes, including arginine decarboxylase, phytase, and beta-glucosidase aggregating factor as candidates responsible for Al tolerance based on transcriptome analysis. Al stress led to changes in the alternative splicing profile of the Al-tolerant cultivar. These studies demonstrated the transcriptional variations affiliated to Al avoidance/tolerance in contrasting indica rice of North East India and provided us with several candidate genes responsible for Al tolerance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00709-020-01581-2DOI Listing
May 2021

Plant-microbe Interactions for Sustainable Agriculture in the Post-genomic Era.

Curr Genomics 2020 Apr;21(3):168-178

1Faculty of Applied Biological Sciences, Gifu University, Gifu501-1193, Japan; 2Lab of Plant-Microbe Interactions, Centre for DNA Fingerprinting and Diagnostics, Graduate studies: Manipal Academy of Higher Education, Manipal, Karnataka, India; 3Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Rajasthan 305817, India.

Plant-microbe interactions are both symbiotic and antagonistic, and the knowledge of both these interactions is equally important for the progress of agricultural practice and produce. This review gives an insight into the recent advances that have been made in the plant-microbe interaction study in the post-genomic era and the application of those for enhancing agricultural production. Adoption of next-generation sequencing (NGS) and marker assisted selection of resistant genes in plants, equipped with cloning and recombination techniques, has progressed the techniques for the development of resistant plant varieties by leaps and bounds. Genome-wide association studies (GWAS) of both plants and microbes have made the selection of desirable traits in plants and manipulation of the genomes of both plants and microbes effortless and less time-consuming. Stress tolerance in plants has been shown to be accentuated by association of certain microorganisms with the plant, the study and application of the same have helped develop stress-resistant varieties of crops. Beneficial microbes associated with plants are being extensively used for the development of microbial consortia that can be applied directly to the plants or the soil. Next-generation sequencing approaches have made it possible to identify the function of microbes associated in the plant microbiome that are both culturable and non-culturable, thus opening up new doors and possibilities for the use of these huge resources of microbes that can have a potential impact on agriculture.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2174/1389202921999200505082116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7521031PMC
April 2020

A single-population GWAS identified expression level polymorphism caused by promoter variants is associated with variation in aluminum tolerance in a local population.

Plant Direct 2020 Aug 12;4(8):e00250. Epub 2020 Aug 12.

Faculty of Applied Biological Sciences Gifu University Gifu Gifu Japan.

Organic acids (OA) are released from roots in response to aluminum (Al), conferring an Al tolerance to plants that is regulated by OA transporters such as ALMT (Al-activated malate transporter) and multi-drug and toxic compound extrusion (MATE). We have previously reported that the expression level polymorphism (ELP) of is strongly associated with variation in Al tolerance among natural accessions of Arabidopsis. However, although is also expressed following Al exposure and contributes to Al tolerance, whether contributes to the variation of Al tolerance and the molecular mechanisms of ELP remains unclear. Here, we dissected the natural variation in expression level in response to Al at the root using diverse natural accessions of Arabidopsis. Phylogenetic analysis revealed that more than half of accessions belonging to the Central Asia (CA) population show markedly low expression levels, while the majority of European populations show high expression levels. The accessions of the CA population with low expression also show significantly weakened Al tolerance. A single-population genome-wide association study (GWAS) of expression in the CA population identified a retrotransposon insertion in the promoter region associated with low gene expression levels. This may affect the transcriptional regulation of by disrupting the effect of a cis-regulatory element located upstream of the insertion site, which includes AtSTOP1 (sensitive to proton rhizotoxicity 1) transcription factor-binding sites revealed by chromatin immunoprecipitation-qPCR analysis. Furthermore, the GWAS performed without the accessions expressing low levels of , excluding the effect of promoter polymorphism, identified several candidate genes potentially associated with expression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pld3.250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7419912PMC
August 2020

Incidental ectopic posterior pituitary in an adult.

BMJ Case Rep 2020 May 21;13(5). Epub 2020 May 21.

Nagoya City Hospital Management Department, Nagoya City, Nagoya, Japan.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bcr-2020-234415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247410PMC
May 2020

Genome-Wide Association Study and Genomic Prediction Elucidate the Distinct Genetic Architecture of Aluminum and Proton Tolerance in .

Front Plant Sci 2020 9;11:405. Epub 2020 Apr 9.

Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.

Under acid soil conditions, Al stress and proton stress can occur, reducing root growth and function. However, these stressors are distinct, and tolerance to each is governed by multiple physiological processes. To better understand the genes that underlie these coincidental but experimentally separable stresses, a genome-wide association study (GWAS) and genomic prediction (GP) models were created for approximately 200 diverse accessions. GWAS and genomic prediction identified 140/160 SNPs associated with Al and proton tolerance, respectively, which explained approximately 70% of the variance observed. Reverse genetics of the genes in loci identified novel Al and proton tolerance genes, including () and (), as well as genes known to be associated with tolerance, such as the Al-activated malate transporter, . Additionally, variation in Al tolerance was partially explained by expression level polymorphisms of and caused by cis-regulatory allelic variation. These results suggest that we successfully identified the loci that regulate Al and proton tolerance. Furthermore, very small numbers of loci were shared by Al and proton tolerance as determined by the GWAS. There were substantial differences between the phenotype predicted by genomic prediction and the observed phenotype for Al tolerance. This suggested that the GWAS-undetectable genetic factors (e.g., rare-allele mutations) contributing to the variation of tolerance were more important for Al tolerance than for proton tolerance. This study provides important new insights into the genetic architecture that produces variation in the tolerance of acid soil.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2020.00405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7160251PMC
April 2020

Pemafibrate, a selective PPARα modulator, and fenofibrate suppress microglial activation through distinct PPARα and SIRT1-dependent pathways.

Biochem Biophys Res Commun 2020 04 29;524(2):385-391. Epub 2020 Jan 29.

Department of Gastroenterology and Metabolism, Nagoya City University, Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan. Electronic address:

Pemafibrate, a selective peroxisome proliferator-activated receptor (PPAR) α modulator, is a new drug that specifically modulates PPARα conformation and co-activator recruitment, thereby lowers plasma triglycerides with less off-target effects. Classical PPARα ligands such as fenofibrate suppress inflammatory cells including microglia. However, effects of pemafibrate on microglia have never been addressed. Here we show that pemafibrate, like other PPARα ligands, potently suppressed NF-κB phosphorylation and cytokine expression in microglial cells. PPARα knockdown significantly amplified LPS-induced cytokine expression. Pemafibrate-induced suppression of IL-6 expression was reversed by PPARα knockdown. However, suppression by fenofibrate was not reversed by PPARα knockdown but by Sirtuin 1 (SIRT1) knockdown. In conclusion, pemafibrate and fenofibrate similarly suppresses microglial activation but through distinct PPARα and SIRT1-dependet pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2020.01.118DOI Listing
April 2020

Effect of Asfotase Alfa on Muscle Weakness in a Japanese Adult Patient of Hypophosphatasia with Low ALP Levels.

Intern Med 2020 Mar 29;59(6):811-815. Epub 2019 Nov 29.

Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan.

A 40-year-old Japanese woman presented to our hospital with general fatigue and muscle weakness. She had a history of premature loss of deciduous teeth at 4 years old, her serum alkaline phosphatase (ALP) activity was as low as 91 U/L, and radiologic studies revealed thoracic deformity and sacroiliac calcification. Genetic sequencing revealed a heterozygous c.1559delT mutation in the tissue non-specific alkaline phosphatase gene (ALPL). Based on these findings, she was diagnosed with hypophosphatasia (HPP), and treatment with asfotase alfa, a recombinant human tissue-nonspecific alkaline phosphatase (TNSALP), was initiated. After six months of treatment with asfotase alfa, improvements were observed in the SF-36 score, six-minute walk distance, and grasping power. Although the overdiagnosis needs to be avoided, HPP should be considered in patients with undiagnosed musculoskeletal symptoms and a low serum ALP activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2169/internalmedicine.3298-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7118397PMC
March 2020

Bicycle exercise training improves ambulation in patients with peripheral artery disease.

J Vasc Surg 2020 03 5;71(3):979-987. Epub 2019 Sep 5.

Department of Mechano-Informatics, The University of Tokyo, Tokyo, Japan.

Objective: Exercise training has multiple beneficial effects in patients with arteriosclerotic diseases; however, the exact underlying mechanisms of the effects are not completely understood. This study aimed to evaluate the effectiveness of a supervised exercise program in improving gait parameters, including the variability and walking performance of lower limb movements, in patients with peripheral artery disease (PAD) and intermittent claudication (IC).

Methods: Sixteen patients with a history of PAD and IC were recruited for this study, and they completed a 3-month supervised bicycle exercise program. The ankle-brachial index and responses to quality of life (QOL) questionnaires were evaluated. Near-infrared spectroscopy was also performed to determine the hemoglobin oxygen saturation in the calf. Patients' kinematics and dynamics, including joint range of motion and muscle tension, were evaluated using an optical motion capture system. Computed tomography images of each muscle were assessed by manual outlining. Data were collected before and after the supervised bicycle exercise program, and differences were analyzed.

Results: Significant differences were not found in step length, ankle-brachial index, and hemoglobin oxygen saturation before and after the supervised bicycle exercise program; however, IC distance (P = .034), maximum walking distance (P = .006), and all QOL questionnaire scores (P < .001) showed significant improvement. Hip range of motion (P = .035), maximum hip joint torque (right, P = .031; left, P = .044), maximum tension of the gluteus maximus muscle (right, P = .044; left, P = .042), and maximum hip joint work (right, P = .048; left, P = .043) also significantly decreased bilaterally. Computed tomography images showed a significant increase in the cross-sectional area of the abdominal, trunk, and thigh muscles but not in that of the lower leg muscles after the supervised exercise program intervention.

Conclusions: In this study, bicycle exercise training improved the QOL and walking distance and decreased hip movement. The results showed that bicycling might be as useful as walking in patients with PAD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jvs.2019.06.188DOI Listing
March 2020

Sensitive to Proton Rhizotoxicity1 Regulates Salt and Drought Tolerance of Arabidopsis thaliana through Transcriptional Regulation of CIPK23.

Plant Cell Physiol 2019 Sep;60(9):2113-2126

Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, Japan.

The transcription factor sensitive to proton rhizotoxicity 1 (STOP1) regulates multiple stress tolerances. In this study, we confirmed its involvement in NaCl and drought tolerance. The root growth of the T-DNA insertion mutant of STOP1 (stop1) was sensitive to NaCl-containing solidified MS media. Transcriptome analysis of stop1 under NaCl stress revealed that STOP1 regulates several genes related to salt tolerance, including CIPK23. Among all available homozygous T-DNA insertion mutants of the genes suppressed in stop1, only cipk23 showed a NaCl-sensitive root growth phenotype comparable to stop1. The CIPK23 promoter had a functional STOP1-binding site, suggesting a strong CIPK23 suppression led to NaCl sensitivity of stop1. This possibility was supported by in planta complementation of CIPK23 in the stop1 background, which rescued the short root phenotype under NaCl. Both stop1 and cipk23 exhibited a drought tolerant phenotype and increased abscisic acid-regulated stomatal closure, while the complementation of CIPK23 in stop1 reversed these traits. Our findings uncover additional pleiotropic roles of STOP1 mediated by CIPK23, which regulates various ion transporters including those regulating K+-homeostasis, which may induce a trade-off between drought tolerance and other traits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/pcp/pcz120DOI Listing
September 2019

Redox balance, metabolic fingerprint and physiological characterization in contrasting North East Indian rice for Aluminum stress tolerance.

Sci Rep 2019 06 18;9(1):8681. Epub 2019 Jun 18.

Assam University, Department of Life Science and Bioinformatics, Plant Molecular Biotechnology Lab, 788011, Silchar, India.

Aluminum (Al) toxicity is a serious problem for rice crop productivity in acidic soils worldwide. The present work was conducted to look out for the alteration in ROS homeostasis; metabolic fingerprint; and morphology in two contrasting Indica rice cultivars of North East India (NE India) to Al toxicity. Al stress led to excess accumulation of ROS (HO and O), and this in turn induced ROS mediated cellular damage, as indicated by lipid peroxidation both qualitatively as well as quantitatively. This excessive ROS production also led to significant reduction in chlorophyll content and stomatal conductance. This was followed by the loss of photosynthetic efficiency as detected by chlorophyll fluorescence. This excessive damage due to ROS prompted us to check the anti-oxidative machinery. Antioxidants, especially enzymes (SOD, APX, POX, GR, CAT, DHAR, MDHAR) are very important players in maintenance of ROS homeostasis. In tolerant variety Disang, higher activity of these enzymes and vice versa in sensitive variety, was observed in response to Al treatment. The non-enzymatic antioxidants (proline, ascorbate and glutathione) also showed similar trend. Though the tolerant variety showed strong anti-oxidative machinery, it was unable to completely nullify the stress experienced by the seedlings. Organic acids are also important players in detoxification of Al stress through efflux in the rhizosphere. In tolerant genotype, citrate exudate was found to be more when compared to sensitive genotypes on exposure to high dose of Al. This is supported by higher abundance of FRDL4, a citrate transporter. Not only FRDL4, other stakeholders for Al stress response like ART1 and ALS1 depicted prominent transcript abundance in the tolerant variety. In conclusion, through this study detailed physiological and metabolic characterisation of two contrasting Indica rice varieties Disang and Joymati, native to NE India for Al tolerance was performed for the very first time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-45158-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581886PMC
June 2019

Transcriptome Analysis and Identification of a Transcriptional Regulatory Network in the Response to HO.

Plant Physiol 2019 07 7;180(3):1629-1646. Epub 2019 May 7.

United Graduate School of Agricultural Science, Gifu University, Gifu City, Gifu 501-1193, Japan

Hydrogen peroxide (HO) is a common signal molecule initiating transcriptional responses to all the known biotic and abiotic stresses of land plants. However, the degree of involvement of HO in these stress responses has not yet been well studied. Here we identify time-dependent transcriptome profiles stimulated by HO application in Arabidopsis () seedlings. Promoter prediction based on transcriptome data suggests strong crosstalk among high light, heat, and wounding stress responses in terms of environmental stresses and between the abscisic acid (ABA) and salicylic acid (SA) responses in terms of phytohormone signaling. Quantitative analysis revealed that ABA accumulation is induced by HO but SA is not, suggesting that the implied crosstalk with ABA is achieved through ABA accumulation while the crosstalk with SA is different. We identified potential direct regulatory pairs between regulator transcription factor (TF) proteins and their regulated TF genes based on the time-course transcriptome analysis for the HO response, in vivo regulation of the regulated TF by the regulator TF identified by expression analysis of mutants and overexpressors, and in vitro binding of the regulator TF protein to the target TF promoter. These analyses enabled the establishment of part of the transcriptional regulatory network for the HO response composed of 15 regulatory pairs of TFs, including five pairs previously reported. This regulatory network is suggested to be involved in a wide range of biotic and abiotic stress responses in Arabidopsis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.18.01426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752916PMC
July 2019

Involvement of phosphatidylinositol metabolism in aluminum-induced malate secretion in Arabidopsis.

J Exp Bot 2019 06;70(12):3329-3342

Applied Biological Sciences, Gifu University, Gifu, Japan.

To identify the upstream signaling of aluminum-induced malate secretion through aluminum-activated malate transporter 1 (AtALMT1), a pharmacological assay using inhibitors of human signal transduction pathways was performed. Early aluminum-induced transcription of AtALMT1 and other aluminum-responsive genes was significantly suppressed by phosphatidylinositol 4-kinase (PI4K) and phospholipase C (PLC) inhibitors, indicating that the PI4K-PLC metabolic pathway activates early aluminum signaling. Inhibitors of phosphatidylinositol 3-kinase (PI3K) and PI4K reduced aluminum-activated malate transport by AtALMT1, suggesting that both the PI3K and PI4K metabolic pathways regulate this process. These results were validated using T-DNA insertion mutants of PI4K and PI3K-RNAi lines. A human protein kinase inhibitor, putatively inhibiting homologous calcineurin B-like protein-interacting protein kinase and/or Ca-dependent protein kinase in Arabidopsis, suppressed late-phase aluminum-induced expression of AtALMT1, which was concomitant with the induction of an AtALMT1 repressor, WRKY46, and suppression of an AtALMT1 activator, Calmodulin-binding transcription activator 2 (CAMTA2). In addition, a human deubiquitinase inhibitor suppressed aluminum-activated malate transport, suggesting that deubiquitinases can regulate this process. We also found a reduction of aluminum-induced citrate secretion in tobacco by applying inhibitors of PI3K and PI4K. Taken together, our results indicated that phosphatidylinositol metabolism regulates organic acid secretion in plants under aluminum stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/erz179DOI Listing
June 2019

-mediated hairy roots transformation as a tool for exploring aluminum-responsive genes function.

Future Sci OA 2019 Mar 8;5(3):FSO364. Epub 2019 Feb 8.

Laboratory of Plant Cell Technology, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.

Aim: To develop a useful alternative approach to evaluate the gene function in hairy roots.

Methods: and tobacco (wild-type or mutant) were a host for transformation.

Results: The hairy roots formation efficiency ranged from 53 to 98% in tobacco and 53 to 66% in . Hairy and intact roots showed similar gene expression pattern in response to salt and aluminum stress. Genomic polymerase chain reaction and fluorescent images showed high rate (>80%) of co-integration of T-DNAs and uniform cell transformation without use of any antibiotic selection. Whole processes of hairy roots were completed within 1 month after the infection of .

Conclusion: Aluminum-responsive orthologous gene function could be evaluated by KD and as a host for hairy roots transformation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4155/fsoa-2018-0065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6426172PMC
March 2019

STOP1 regulates the expression of HsfA2 and GDHs that are critical for low-oxygen tolerance in Arabidopsis.

J Exp Bot 2019 06;70(12):3297-3311

Applied Biological Sciences, Gifu University, Gifu, Japan.

The SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) transcription factor regulates gene expression associated with multiple stress tolerances in plant roots. In this study, we investigated the mechanism responsible for the sensitivity of the stop1 mutant to low-oxygen stress in Arabidopsis. Transcriptomic analyses revealed that two genes involved in low-oxygen tolerance, namely GLUTAMATE DEHYDROGENASE 1 (GDH1) and GDH2, showed lower expression levels in the stop1 mutant than in the wild-type. Sensitivity of the gdh1gdh2 double-mutant to low-oxygen conditions was partly attributable to the low-oxygen sensitivity of the stop1 mutant. Two transcription factors, STOP2 and HEAT SHOCK FACTOR A2 (HsfA2), were expressed at lower levels in the stop1 mutant. An in planta complementation assay indicated that CaMV35S::STOP2 or CaMV35S::HsfA2 partially rescued the low-oxygen tolerance of the stop1 mutant, which was concomitant with recovered expression of genes regulating low-pH tolerance and genes encoding molecular chaperones. Prediction of cis-elements and in planta promoter assays revealed that STOP1 directly activated the expression of HsfA2. Similar STOP1-dependent low-oxygen sensitivity was detected in tobacco. Suppression of NtSTOP1 induced low-oxygen sensitivity, which was associated with lower expression levels of NtHsfA2 and NtGDHs compared with the wild-type. Our results indicated that STOP1 pleiotropically regulates low-oxygen tolerance by transcriptional regulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/erz124DOI Listing
June 2019

Comparative genome-wide analysis of WRKY transcription factors in two Asian legume crops: Adzuki bean and Mung bean.

Sci Rep 2018 11 19;8(1):16971. Epub 2018 Nov 19.

Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India.

The seminal participation of WRKY transcription factors in plant development, metabolism and in the governance of defense mechanism implicated their gaining importance for genomic and functional studies. The recent release of draft genome sequences of two legume crops, Adzuki bean (Vigna angularis) and Mung bean (Vigna radiata) has paved the way for characterization of WRKY gene family in these crops. We found 84 WRKY genes in Adzuki bean (VaWRKY) and 85 WRKY genes in Mung bean (VrWRKY). Based on the phylogenetic analysis, VaWRKY genes were classified into three groups with 15 members in Group I, 56 members in Group II, and 13 members in Group III, which was comparable to VrWRKY distribution in Mung bean, 16, 56 and 13 members in Group I, II and III, respectively. The few tandem and segmental duplication events suggested that recent duplication plays no prominent role in the expansion VaWRKY and VrWRKY genes. The illustration of gene-structure and their encoded protein-domains further revealed the nature of WRKY proteins. Moreover, the identification of abiotic or biotic stress-responsive cis-regulatory elements in the promoter regions of some WRKY genes provides fundamental insights for their further implementation in stress-tolerance and genetic improvement of agronomic traits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-34920-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243003PMC
November 2018

Targeting ability of self-assembled nanomedicines in rat acute limb ischemia model is affected by size.

J Control Release 2018 09 1;286:394-401. Epub 2018 Aug 1.

Department of Vascular Surgery, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Electronic address:

Peripheral artery disease (PAD) is one of the most spreading diseases all over the world. The treatment strategies are limited to surgical or endovascular procedures for final stage chronic PAD or acute limb ischemia, and no pharmacological approaches have been achieved to prevent the worsening of chronic PAD or to regenerate the tissues of acute limb ischemia. Therefore, the improvement of therapeutic strategy is strongly demanded in clinics. Here, we adopted an acute hindlimb ischemia model in rats, which provides concomitant inflammatory response, to evaluate the application of drug delivery system against PAD. Through comparative experiments by using different-sized nanomedicine analogues, polyion complex (PIC) micelles with 30 nm diameter and PIC vesicles with 100- and 200-nm diameter (PICs-30, -100, -200 respectively), we found the size-dependent accumulation and retention in the collateral arteries. In contrast to PICs-30 and -200, histological analysis showed that PICs-100 were around the arterioles and co-localized with macrophages, which indicates that the PICs-100 can achieve moderate interaction with phagocytes. Our data suggests that controlling the size of nanomedicines has promise for developing novel angiogenic treatments toward the effective management of collateral arteries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jconrel.2018.07.049DOI Listing
September 2018

Kinematic characteristics of barefoot sprinting in habitually shod children.

PeerJ 2018 13;6:e5188. Epub 2018 Jul 13.

Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan.

Background: Anecdotally, a wide variety of benefits of barefoot running have been advocated by numerous individuals. The influence of the alterations in the properties of the shoe on the running movement has been demonstrated in adults at submaximal jogging speeds. However, the biomechanical differences between shod and barefoot running in children at sprinting speeds and the potential developmental implications of these differences are still less examined. The purpose was to determine the potential differences in habitually shod children's sprint kinematics between shod and barefoot conditions.

Methods: Ninety-four children (51 boys and 43 girls; 6-12 years-old; height, 135.0 ± 0.12 m; body mass, 29.0 ± 6.9 kg) performed 30 m maximal sprints from standing position for each of two conditions (shod and barefoot). To analyze sprint kinematics within sagittal plane sprint kinematics, a high-speed camera (300 fps) was set perpendicular to the runway. In addition, sagittal foot landing and take-off images were recorded for multiple angles by using five high-speed cameras (300 fps). Spatio-temporal variables, the kinematics of the right leg (support leg) and the left leg (recovery leg), and foot strike patterns: rear-foot strike (RFS), mid-foot strike (MFS), and fore-foot strike (FFS) were investigated. The paired -test was used to test difference between shod and barefoot condition.

Results: Barefoot sprinting in habitually shod children was mainly characterized by significantly lower sprint speed, higher step frequency, shorter step length and stance time. In shod running, 82% of children showed RFS, whereas it decreased to 29% in barefoot condition. The touch down state and the subsequent joint movements of both support and recovery legs during stance phase were significantly altered when running in condition with barefoot.

Discussion: The acute effects of barefoot sprinting was demonstrated by significantly slower sprinting speeds that appear to reflect changes in a variety of spatiotemporal parameters as well as lower limb kinematics. It is currently unknown whether such differences would be observed in children who typically run in bare feet and what developmental benefits and risks may emerge from increasing the proportion of barefoot running and sprinting in children. Future research should therefore investigate potential benefits that barefoot sprinting may have on the development of key physical fitness such as nerve conduction velocity, muscular speed, power, and sprinting technique and on ways to minimize the risk of any acute or chronic injuries associated with this activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7717/peerj.5188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6047502PMC
July 2018

A Case of Euthyroid Graves' Ophthalmopathy in a Patient Sero-Negative for TSH Receptor Autoantibody.

Case Rep Endocrinol 2018 13;2018:1707959. Epub 2018 Jun 13.

Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.

We report of a case of Graves' ophthalmopathy presented solely with symptoms of the eyes with normal thyroid function tests and negative immunoreactive TSH receptor autoantibody. 40-year-old male was referred to our hospital due to 2-month history of ocular focusing deficit without any signs or symptoms of hyper- or hypothyroidism. Serum thyroid function tests and Tc uptake were both within the normal range. Anti-thyroid autoantibodies were all negative except for the cell-based assay for serum TSH receptor stimulating activity. Since orbital CT scan and MRI gave typical results compatible with Graves' ophthalmopathy, we treated the patients with corticosteroid pulse therapy and orbital radiation therapy, leading to a partial improvement of the symptoms. This case gives insights into the potential pathophysiologic mechanism underlying Graves' ophthalmopathy and casts light upon the difficulties of establishing the diagnosis in a euthyroid case with minimal positive results for anti-thyroid autoantibodies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2018/1707959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6020486PMC
June 2018

An Autopsy Case of Pulmonary Tumor Thrombotic Microangiopathy Due to Rapidly Progressing Colon Cancer in a Patient with Type 2 Diabetes.

Intern Med 2018 Sep 30;57(17):2533-2539. Epub 2018 Mar 30.

Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Japan.

We herein describe a case of pulmonary tumor thrombotic microangiopathy (PTTM) with rapidly progressing colon cancer. A 61-year-old man who had been receiving treatment for type 2 diabetes mellitus for 3 years was hospitalized due to critical hypoxemia. Computed tomography, which had not shown any abnormalities 3 months previously, revealed a tumor in the ascending colon, multiple nodules in the liver, and the absence of any lung abnormalities. On day 3 of hospitalization, a sudden onset of severe dyspnea and tachycardia occurred, followed by death. Autopsy revealed microscopic metastatic tumor emboli in multiple pulmonary vessels with fibrin thrombus and intimal proliferation, which led to a diagnosis of PTTM.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2169/internalmedicine.0204-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6172551PMC
September 2018

Glucagon promotes colon cancer cell growth via regulating AMPK and MAPK pathways.

Oncotarget 2018 Feb 31;9(12):10650-10664. Epub 2018 Jan 31.

Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya 467-8601, Japan.

Cancer is one of the major causes of death in diabetic patients, and an association between antidiabetic drugs and cancer risk has been reported. Such evidence implies a strong connection between diabetes and cancer. Recently, glucagon has been recognized as a pivotal factor implicated in the pathophysiology of diabetes. Glucagon acts through binding to its receptor, glucagon receptor (GCGR), and cross-talk between GCGR-mediated signals and signaling pathways that regulate cancer cell fate has been unveiled. In the current study, expression of GCGR in colon cancer cell lines and colon cancer tissue obtained from patients was demonstrated. Glucagon significantly promoted colon cancer cell growth, and GCGR knockdown with small interfering RNA attenuated the proliferation-promoting effect of glucagon on colon cancer cells. Molecular assays showed that glucagon acted as an activator of cancer cell growth through deactivation of AMPK and activation of MAPK in a GCGR-dependent manner. Moreover, a stable GCGR knockdown mouse colon cancer cell line, CMT93, grew significantly slower than control in a syngeneic mouse model of type 2 diabetes with glycemia and hyperglucagonemia. The present observations provide experimental evidence that hyperglucagonemia in type 2 diabetes promotes colon cancer progression via GCGR-mediated regulation of AMPK and MAPK pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.24367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828215PMC
February 2018

Dark conditions enhance aluminum tolerance in several rice cultivars via multiple modulations of membrane sterols.

J Exp Bot 2018 01;69(3):567-577

Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.

Aluminum-sensitive rice (Oryza sativa L.) cultivars showed increased Al tolerance under dark conditions, because less Al accumulated in the root tips (1 cm) under dark than under light conditions. Under dark conditions, the root tip concentration of total sterols, which generally reduce plasma membrane permeabilization, was higher in the most Al-sensitive japonica cultivar, Koshihikari (Ko), than in the most Al-tolerant cultivar, Rikuu-132 (R132), but the phospholipid content did not differ between the two. The Al treatment increased the proportion of stigmasterol (which has no ability to reduce membrane permeabilization) out of total sterols similarly in both cultivars under light conditions, but it decreased more in Ko under dark conditions. The carotenoid content in the root tip of Al-treated Ko was significantly lower under dark than under light conditions, indicating that isopentenyl diphosphate transport from the cytosol to plastids was decreased under dark conditions. HMG2 and HMG3 (encoding the key sterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl CoA reductase) transcript levels in the root tips were enhanced under dark conditions. We suggest that the following mechanisms contribute to the increase in Al tolerance under dark conditions: inhibition of stigmasterol formation to retain membrane integrity; greater partitioning of isopentenyl diphosphate for sterol biosynthesis; and enhanced expression of HMGs to increase sterol biosynthesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/erx414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853495PMC
January 2018

Nocturnal reactive hypoglycaemia well treated subjectively and objectively with voglibose.

BMJ Case Rep 2017 Oct 4;2017. Epub 2017 Oct 4.

Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Aichi, Japan.

Clinicians sometimes encounter difficulty in diagnosing hypoglycaemia. Here, we present a case report of a 53-year-old woman with recurrent nocturnal hypoglycaemia. A continuous glucose monitoring system (CGMS) revealed postprandial hyperglycaemia and subsequent hypoglycaemia, and an oral glucose tolerance test showed an impaired glycaemic and delayed hyperinsulinaemic pattern. On the basis of these clinical findings, we diagnosed her unexplained hypoglycaemia as reactive hypoglycaemia. CGMS showed a sharp contrast of diurnal variation in blood glucose levels including hypoglycaemia between before and after treatment with an alpha-glucosidase inhibitor, voglibose. Her hypoglycaemic attacks disappeared.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bcr-2017-220295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5652509PMC
October 2017

Characterization of CcSTOP1; a C2H2-type transcription factor regulates Al tolerance gene in pigeonpea.

Planta 2018 Jan 18;247(1):201-214. Epub 2017 Sep 18.

Laboratory of Plant Cell Technology, Faculty of Applied Biological Sciences, Gifu University, Gifu, 501-1193, Japan.

Main Conclusion: Al-responsive citrate-transporting CcMATE1 function and its regulation by CcSTOP1 were analyzed using NtSTOP1 -KD tobacco- and pigeonpea hairy roots, respectively, CcSTOP1 binding sequence of CcMATE1 showed similarity with AtALMT1 promoter. The molecular mechanisms of Aluminum (Al) tolerance in pigeonpea (Cajanus cajan) were characterized to provide information for molecular breeding. Al-inducible citrate excretion was associated with the expression of MULTIDRUGS AND TOXIC COMPOUNDS EXCLUSION (CcMATE1), which encodes a citrate transporter. Ectopic expression of CcMATE1-conferred Al tolerance to hairy roots of transgenic tobacco with the STOP1 regulation system knocked down. This gain-of-function approach clearly showed CcMATE1 was involved in Al detoxification. The expression of CcMATE1 and another Al-tolerance gene, ALUMINUM SENSITIVE 3 (CcALS3), was regulated by SENSITIVE TO PROTON RHIZOTOXICITY1 (CcSTOP1) according to loss-of-function analysis of pigeonpea hairy roots in which CcSTOP1 was suppressed. An in vitro binding assay showed that the Al-responsive CcMATE1 promoter contained the GGNVS consensus bound by CcSTOP1. Mutation of GGNVS inactivated the Al-inducible expression of CcMATE1 in pigeonpea hairy roots. This indicated that CcSTOP1 binding to the promoter is critical for CcMATE1 expression. The STOP1 binding sites of both the CcMATE1 and AtALMT1 promoters contained GGNVS and a flanking 3' sequence. The GGNVS region was identical in both CcMATE1 and AtALMT1. By contrast, the 3' flanking sequence with binding affinity to STOP1 did not show similarity. Putative STOP1 binding sites with similar structures were also found in Al-inducible MATE and ALMT1 promoters in other plant species. The characterized Al-responsive CcSTOP1 and CcMATE1 genes will help in pigeonpea breeding in acid soil tolerance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00425-017-2777-6DOI Listing
January 2018

Transcriptional Regulation of Aluminum-Tolerance Genes in Higher Plants: Clarifying the Underlying Molecular Mechanisms.

Front Plant Sci 2017 8;8:1358. Epub 2017 Aug 8.

Faculty of Applied Biological Sciences, Gifu UniversityGifu, Japan.

Aluminum (Al) rhizotoxicity is one of the major environmental stresses that decrease global food production. Clarifying the molecular mechanisms underlying Al tolerance may contribute to the breeding of Al-tolerant crops. Recent studies identified various Al-tolerance genes. The expression of these genes is inducible by Al. Studies of the major Al-tolerance gene, , which encodes an Al-activated malate transporter, revealed that the Al-inducible expression is regulated by a () zinc-finger transcription factor. This system, which involves STOP1 and organic acid transporters, is conserved in diverse plant species. The expression of is also upregulated by several phytohormones and hydrogen peroxide, suggesting there is crosstalk among the signals involved in the transcriptional regulation of . Additionally, phytohormones and reactive oxygen species (ROS) activate various transcriptional responses, including the expression of genes related to increased Al tolerance or the suppression of root growth under Al stress conditions. For example, Al suppressed root growth due to abnormal accumulation of auxin and cytokinin. It activates transcription of and other phytohormone responsive genes in distal transition zone, which causes suppression of root elongation. On the other hand, overexpression of Al inducible genes for ROS-detoxifying enzymes such as , , enhances Al resistance in several plant species. We herein summarize the complex transcriptional regulation of an Al-inducible genes affected by STOP1, phytohormones, and ROS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2017.01358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5550694PMC
August 2017
-->