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Search Results: 1 - 10 of 1280 matches for " Yasuhiro Ishiga "
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Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions
Yasuhiro Ishiga, Takako Ishiga, Srinivasa R Uppalapati, Kirankumar S Mysore
Plant Methods , 2011, DOI: 10.1186/1746-4811-7-32
Abstract: In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1) the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS) and phytotoxin coronatine (COR); 2) the effector-triggered immunity; and 3) Arabidopsis mutants affected in salicylic acid (SA)- and pathogen-associated molecular pattern (PAMPs)-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR) responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2) in NHR.The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to Xanthomonas campestris pv. vesicatoria. This method is potentially ideal for high-throughput screening of both Arabidopsis and pathogen mutants.One of the model pathosystems for the study of plant-pathogen interactions is Arabidopsis thaliana-Pseudomonas syringae interaction [1]. This model system has been widely used to understand a number of dynamic and complex molecular events in both resistance and susceptible interactions. In addition, P. syringae pvs. tomato an
Jasmonate ZIM-Domain (JAZ) Protein Regulates Host and Nonhost Pathogen-Induced Cell Death in Tomato and Nicotiana benthamiana
Yasuhiro Ishiga, Takako Ishiga, Srinivasa Rao Uppalapati, Kirankumar S. Mysore
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0075728
Abstract: The nonhost-specific phytotoxin coronatine (COR) produced by several pathovars of Pseudomonas syringae functions as a jasmonic acid-isoleucine (JA-Ile) mimic and contributes to disease development by suppressing plant defense responses and inducing reactive oxygen species in chloroplast. It has been shown that the F-box protein CORONATINE INSENSITIVE 1 (COI1) is the receptor for COR and JA-Ile. JASMONATE ZIM DOMAIN (JAZ) proteins act as negative regulators for JA signaling in Arabidopsis. However, the physiological significance of JAZ proteins in P. syringae disease development and nonhost pathogen-induced hypersensitive response (HR) cell death is not completely understood. In this study, we identified JAZ genes from tomato, a host plant for P. syringae pv. tomato DC3000 (Pst DC3000), and examined their expression profiles in response to COR and pathogens. Most JAZ genes were induced by COR treatment or inoculation with COR-producing Pst DC3000, but not by the COR-defective mutant DB29. Tomato SlJAZ2, SlJAZ6 and SlJAZ7 interacted with SlCOI1 in a COR-dependent manner. Using virus-induced gene silencing (VIGS), we demonstrated that SlJAZ2, SlJAZ6 and SlJAZ7 have no effect on COR-induced chlorosis in tomato and Nicotiana benthamiana. However, SlJAZ2-, SlJAZ6- and SlJAZ7-silenced tomato plants showed enhanced disease-associated cell death to Pst DC3000. Furthermore, we found delayed HR cell death in response to the nonhost pathogen Pst T1 or a pathogen-associated molecular pattern (PAMP), INF1, in SlJAZ2- and SlJAZ6-silenced N. benthamiana. These results suggest that tomato JAZ proteins regulate the progression of cell death during host and nonhost interactions.
Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens
Seonghee Lee,Yasuhiro Ishiga,Kristen Clermont,Kirankumar?S. Mysore
PeerJ , 2013, DOI: 10.7717/peerj.34
Abstract: Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR), which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS)-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.
Drought Stress Acclimation Imparts Tolerance to Sclerotinia sclerotiorum and Pseudomonas syringae in Nicotiana benthamiana
Venkategowda Ramegowda,Muthappa Senthil-Kumar,Yasuhiro Ishiga,Amita Kaundal,Makarla Udayakumar,Kirankumar S. Mysore
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14059497
Abstract: Acclimation of plants with an abiotic stress can impart tolerance to some biotic stresses. Such a priming response has not been widely studied. In particular, little is known about enhanced defense capacity of drought stress acclimated plants to fungal and bacterial pathogens. Here we show that prior drought acclimation in Nicotiana benthamiana plants imparts tolerance to necrotrophic fungus, Sclerotinia sclerotiorum, and also to hemi-biotrophic bacterial pathogen, Pseudomonas syringae pv. tabaci. S. sclerotiorum inoculation on N. benthamiana plants acclimated with drought stress lead to less disease-induced cell death compared to non-acclimated plants. Furthermore, inoculation of P. syringae pv. tabaci on N. benthamiana plants acclimated to moderate drought stress showed reduced disease symptoms. The levels of reactive oxygen species (ROS) in drought acclimated plants were highly correlated with disease resistance. Further, in planta growth of GFPuv expressing P. syringae pv. tabaci on plants pre-treated with methyl viologen showed complete inhibition of bacterial growth. Taken together, these experimental results suggested a role for ROS generated during drought acclimation in imparting tolerance against S. sclerotiorum and P. syringae pv. tabaci. We speculate that the generation of ROS during drought acclimation primed a defense response in plants that subsequently caused the tolerance against the pathogens tested.
Arabidopsis Heterotrimeric G-Proteins Play a Critical Role in Host and Nonhost Resistance against Pseudomonas syringae Pathogens
Seonghee Lee, Clemencia M. Rojas, Yasuhiro Ishiga, Sona Pandey, Kirankumar S. Mysore
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082445
Abstract: Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking functional Gα, Gβ and Gγ1Gγ2 proteins displayed enhanced bacterial growth and disease susceptibility in response to host and nonhost pathogens. Mutations of single Gγ subunits Gγ1, Gγ2 and Gγ3 did not alter bacterial disease resistance. Some specificity of subunit usage was observed when comparing host pathogen versus nonhost pathogen. Overexpression of both Gα and Gβ led to reduced bacterial multiplication of nonhost pathogen P. syringae pv. tabaci whereas overexpression of Gβ, but not of Gα, resulted in reduced bacterial growth of host pathogen P. syringae pv. maculicola, compared to wild-type Col-0. Moreover, the regulation of stomatal aperture by bacterial pathogens was altered in Gα and Gβ mutants but not in any of the single or double Gγ mutants. Taken together, these data substantiate the critical role of heterotrimeric G-proteins in plant innate immunity and stomatal modulation in response to P. syringae.
Working Memory in Patients with Major Depressive Disorder  [PDF]
Yasuhiro Kaneda
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.329115
Abstract: Objective: Patients with major depressive disorder (MDD) have been reported to perform less well in neurocognitive tests than normal control subjects. The author tested the hypotheses that verbal working memory (WM) is predictive of the functional outcome in patients with MDD. Methods: In this naturalistic longitudinal study, the subjects consisted of 22 adult outpatients receiving paroxetine as antidepressant therapy. Functional outcome was rated on a scale of 0 (non-impaired) to 3 (severely impaired). Results: 1) At 12 weeks, nine of the 22 patients currently experiencing MDD exhibited full remission; 2) significantly decreased 7-item Hamilton Rating Scale for Depression (HAM-D7) scores were observed during the 12-week study period, while Digit Sequencing Task (DST) scores increased significantly; 3) at baseline, functional outcomes correlated significantly with HAM-D7 scores, but, at 12 weeks, correlated significantly with both HAM-D7 and DST scores. Furthermore, when looking at only patients in full or partial remission (mild depression), functional outcome correlated more strongly with DST than with HAM-D7 scores. Conclusions: A deficit of verbal WM correlated with the functional outcome after treatment in pa- tients with MDD. Antidepressant therapy with paroxetine might contribute to improvement of verbal WM.
Clinical and pathobiological heterogeneity of asthma—Mechanisms of severe and glucocorticoid-resistant asthma  [PDF]
Yasuhiro Matsumura
Health (Health) , 2013, DOI: 10.4236/health.2013.52A046
Abstract:

It is increasingly recognized that asthma represents a syndrome, and there is clinical and pathobiological heterogeneity. Many genes are reported to be associated with asthma, and may be involved in the disease heterogeneity. Diverse cells, such as T helper 1 (Th1)-cells, Th2-cells, Th17-cells, airway epithelial cells, and innate and adaptive immunity associated cells, contribute to the pathobiology of asthma independently of each other or they can also coexist and interact. Although, generally, Th2 immunity is important in most asthma endotypes, non- Th2-driven inflammation tends to be difficult to manage. Recently, increased attention has been focused on severe asthma and glucocorticoid (GC)-resistant (GC-R) asthma, in which diverse inflammatory processes may be involved. Treatment approaches should take into account pathological differences.

A Critical Review of Selye’s Stress Theory: The Statistical Analyses of Selye’s Own Experimental Data Disprove It  [PDF]
Yasuhiro Nageishi
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.614175
Abstract: Selye’s article (Selye, 1936a) published in “Nature” has been enormously cited and markedly affected the entire field of “stress”, until today. The key concept of Selye’s stress theory was “the principle of nonspecificity”. Selye defined stress as the nonspecific responses of the body to various noxious agents. He gave various noxious stimuli to rats, and reported the results in his paper (Selye, 1936b). However, he described only raw data (thymus, and adrenal weights in individual rats), without even the mean values. This study analyzed those data statistically. Among his data, the result pattern most frequently observed was the both occurrences of thymus involution and adrenal enlargement. It appeared to give a conclusive evidence for Selye’s theory. However, there were also other two result patterns. The second pattern was a significant decrease in the thymus weight without changes in the adrenal weight (fasting for 24 - 96 hours in 3-month-old rats, morphine injections, and skin lesions). The third pattern was no change in either the thymus or adrenal weight (exposure to heat and bone fractures). These results disproved Selye’s theory of nonspecificity and they forsook it. And moreover, it was suggested that Selye’s results themselves supported Mason’s proposal that all stress responses were elicited through psychological emotional reactions (Mason, 1971), which were very compatible with the recent psychological stress theories.
Parallel Computing of Discrete Element Method on GPU  [PDF]
Teruyoshi Washizawa, Yasuhiro Nakahara
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.41A037
Abstract:

General purpose computing on GPU for scientific computing has been rapidly growing in recent years. We investigate the applicability of GPU to discrete element method (DEM) often used in particle motion simulation. NVIDIA provides a sample code for this type of simulation, which obtained superior performance than CPU in computational time. A computational model of the contact force in NVIDIA’s sample code is, however, too simple to use in practice. This paper modifies the NVIDIA’s simple model by replacing it with the practical model. The computing speed of the practical model on GPU is compared with the simple one on GPU and with the practical one on CPU in numerical experiments. The result shows that the practical model on GPU obtains the computing speed 6 times faster than the practical one on CPU while 7 times slower than that of the simple one on GPU. The effects of the GPU architectures on the computing speed are analyzed.

Cardiac Arrest Cases and Automated External Defibrillator Use in Railroad Stations in Tokyo  [PDF]
Satoko Fukuike, Yasuhiro Otomo
International Journal of Clinical Medicine (IJCM) , 2014, DOI: 10.4236/ijcm.2014.520170
Abstract: Objective: Nationwide dissemination of public-access defibrillation (PAD) contributed to an increase of survival rate in Japan. We analysed cardiac arrests (CAs) that occurred in railroad stations in Tokyo to evaluate PAD in the metropolis. Methods: We collected Utstein data from the Tokyo Fire Department (TFD) and analysed CA cases that occurred in stations. In total, 245 non-traumatic CAs from January 1, 2007 to March 31, 2008 were analysed; CAs in children under 8 years were excluded. Results: The rates of pre-hospital return of spontaneous circulation (ROSC) were 41 out of 145 witnessed CA patients (28.3%) and 12 ROSC out of 100 unwitnessed CA patients (12%). Of 245 CA cases, bystander cardiopulmonary resuscitation (CPR) performed in 156 (63.7%), automated external defibrillator (AED) used in 117 (47.8%) and shock delivered in 65 (26.5%). Rates of ROSC were 31.6% (37/117) with AED use significantly higher than those of 12.5% (16/128) without AED use (P < 0.001). Most CAs occurred on platforms; the use of AEDs on platforms increased from 18/31 (58.1%) in 2007 to 32/43 (74.4%) in 2008 and ROSC rates increased from 8 (25.8%) to 14 (32.6%), respectively. On train CAs: ROSC cases were very few, 1 case each year (8.3%; 7.7%) while the use of AED increased from 8/12 (66.7%) in 2007 to 10/13 (76.9%) in 2008. Conclusion: Bystander CPR and the use of AED at railroad stations improved ROSC for out-of-hospital cardiac arrest (OHCA) patients. AED location and strategies for dealing with CAs on trains should be re-evaluated.
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