Prefectural University of Kumamoto
Kumamoto-shi, Japan

Prefectural University of Kumamoto is a public university in the city of Kumamoto, Kumamoto, Japan. The predecessor of the school was founded in 1947. The school population is approximately 2,200 students and 100 faculty members. Wikipedia.

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Zushi K.,University of Miyazaki | Matsuzoe N.,Prefectural University of Kumamoto
Scientia Horticulturae | Year: 2017

Salt is a major environmental stress to plant growth and productivity in tomato. Sensing salt stress is important to evaluate the degree of damage and the change in physiological condition in tomato plants. The aim of this study was to evaluate the salt stress in leaves and fruits in tomato using the chlorophyll a fluorescence OJIP transients (OJIP transients). Tomato plants were grown under various levels of salt stress (25, 50, 75, and 100 mM NaCl), following which we measured leaf stress indicators and OJIP transients in leaves and green fruits. In leaf stress indicators, the water potential decreased with increasing levels of salt stress, whereas the chlorophyll content (SPAD value) and the electrolyte leakage were not affected, except in 100 mM NaCl. The overall OJIP curves and each OJIP step in leaves decreased with increasing levels of salt stress, but were unaffected at the lowest level of salt stress (25 mM NaCl). Therefore, the OJIP curves were more sensitive indicators of salt stress in leaves than SPAD and electrolyte leakage. Conversely, in fruit, the OJIP curve was only significantly different in 100 mM NaCl compared with the control, and energy fluxes described by energy pipeline models were higher in 100 mM NaCl than in the control. These results indicate that, in severe salt stress such as 100 mM NaCl of fruit, JIP parameters and energy fluxes can show photosynthetic changes due to the increase in energy absorption efficiency of photosystem II against severe salt stress. Therefore, we conclude that OJIP transient analysis can be used as a non-destructive, simple, and rapid technique for sensing salt stress in tomato. © 2017 Elsevier B.V.

Inoue A.,Prefectural University of Kumamoto | Sakamoto M.,Prefectural University of Kumamoto
Ecological Research | Year: 2017

We compared several methods for quantifying the culm surface area (S) of one of the most common bamboos in Japan, Phyllostachys pubescens Mazel ex Houz. Nine sample culms of P. pubescens were felled, and the true S was determined by the fine resolution analysis of the culm form (SFRA). The S was then calculated independently with the sectional measurement method from the successive diameters measured at equal intervals of one-twentieth (S20), one-tenth (S10), one-fifth (S5) and one-half (S2) of the total culm length. The S was also quantified geometrically from the total culm length and the diameter at breast height or at base by assuming that the culm form could be approximated by a cone (SDBH and SDAB). The SFRA was compared with each of the computed S values. For S10, S5 and S2, both the mean relative bias (%BIAS) and relative root mean square error (%RMSE) decreased with an increase in the number of measured diameters. The %BIAS and %RMSE of the S10 were, respectively, comparable and smaller compared to those of S20. The bias of the SDBH and SDAB suggested that the cone assumption of the culm form was violated. In conclusion, we recommend that the S should be quantified from the successive diameters measured at equal intervals of one-tenth of the total culm length using the sectional measurement method. © 2017, The Ecological Society of Japan.

Zushi K.,Shokei College | Matsuzoe N.,Prefectural University of Kumamoto
Scientia Horticulturae | Year: 2011

In tomato production, salt stress is applied to improve the fruit quality. The change in sensory attributes and organoleptic compositions in salt-stressed tomato fruits have been extensively studied; however, little is known about their interaction with each other. Correlation network analysis provides a visual representation of biological systems and useful knowledge for metabolic data analysis of tomato fruits. The aim of this study is to identify the cultivar differences in sensory attributes and organoleptic compositions of tomato fruits grown under salt stress and to elucidate their interaction among different cultivars using correlation network analysis. Salt stress was applied by adding 100. mM NaCl to the nutrient solution. Fruits were harvested at red-ripe stage and used for the evaluation of sensory attributes such as sweetness, sourness, umami, and tomato like, and organoleptic compositions such as sugar, organic acid, amino acid, and sodium ion contents. Almost all of the sensory attributes and organoleptic compositions of the fruit were significantly high in salt-stressed cultivars compared to non-stressed cultivars, and significant differences were also observed among cultivars. The correlation network analysis of the control fruit showed that compared to other traits, sugar is one of the key traits for improvement of tomato fruit quality based on high connectivity and betweenness centrality. In contrast, a high degree of positive connectivity was not observed between organoleptic compositions and sensory attributes in the salt-stressed fruit network. These results indicate that the relationship between sensory attributes and organoleptic compositions in fruits were different between the control and salt-stressed cultivars, suggesting that the salt-stressed fruit may have a different circuit of relationship compared to control. Furthermore, based on the increase ratio (salt stress/control) network results, we suggest that the increased sugar, organic acid, and amino acid contents may have contributed to the salt stress-induced enhancement of sensory attributes. © 2011 Elsevier B.V.

Zushi K.,Shokei College | Kajiwara S.,Prefectural University of Kumamoto | Matsuzoe N.,Prefectural University of Kumamoto
Scientia Horticulturae | Year: 2012

In tomato production, extreme temperatures such as heat and chilling are major factors limiting growth and productivity. Recently, the chlorophyll a fluorescence OJIP transient (OJIP transient) has been used as an effective tool for studying damage to and activity of the electron transport chain in the photosynthetic apparatus under various environmental stresses. The aim of this study was to evaluate the validity of the OJIP transient as a stress indicator and to characterize the effect of heat and chilling stress on the photosynthetic apparatus in tomato leaf and fruit. Detached leaves and fruits were incubated at 25. °C (control), 40. °C (heat stress), and 4. °C (chilling stress); OJIP transients were measured after exposure to stress for 1. h and 24. h, and several parameters were calculated according to the JIP-test. After exposure to stress for 1. h and 24. h, the OJIP curves and the JIP parameters clearly revealed differences between stress types and between tissue types. In addition, the JIP parameters and the energy pipeline model indicated that heat stress had a greater influence on the photosystem (PS) II electron transport chain than chilling stress, and that changes were greater in the fruit than in the leaf. Furthermore, the PS I electron transport chains of leaf and fruit appeared to be more heat resistant than those in PS II. Our results indicate that, in tomato leaf and fruit, OJIP transients and calculated JIP parameters can be used as sensitive methods for measuring the heat and chilling stress damage to the photosynthetic apparatus, and to identify the action sites of temperature stress. © 2012 Elsevier B.V.

Inoue A.,Prefectural University of Kumamoto | Nishizono T.,Japan Forestry and Forest Products Research Institute
European Journal of Forest Research | Year: 2015

The relationship between stem surface area and stand density was analyzed using a large data set collected from 14 districts for Japanese cedar (Cryptomeria japonica D. Don) and 11 districts for Japanese cypress (Chamaecyparis obtusa Endl.) stands across Japan. The results demonstrated that the mean stem surface area in overcrowded stands was inversely proportional to the stand density for both species and all districts. The inverse relationship indicates that the total stem surface area in overcrowded stands becomes a maximum constant independent of stand density, which is termed the ‘conservation rule of stem surface area.’ Since the stem surface area is proportional to the amount of cambium cells in the stem, the conservation rule suggests that there is an upper limit to the total amount of cambium per unit area, i.e., conservation rule of cambium. The conservation rule of stem surface area was linked to the 3/2 power law of self-thinning by an allometric power exponent between stem surface area and volume. Since the allometric power exponent was approximately equal to 3/2, the self-thinning exponent would vary within a relatively narrow band around −3/2. In conclusion, we hypothesized that the conservation rule of stem surface area, or the conservation rule of cambium, may be an alternative starting point for understanding self-thinning in overcrowded tree populations. © 2015, Springer-Verlag Berlin Heidelberg.

Bolidomonas is a genus of picoplanktonic flagellated algae that is closely related to diatoms. Triparma laevis, a species belonging to the Parmales, which are small cells with a siliceous covering, has been shown to form a monophyletic group with Bolidomonas. We isolated several novel strains of Bolidophyceae that have permitted further exploration of the diversity of this group using nuclear, plastidial and mitochondrial genes. The resulting phylogenetic data led us to formally emend the taxonomy of this group to include the Parmales within the Bolidophyceae, to combine Bolidomonas within Triparma and to define a novel species, Triparma eleuthera sp. nov. The global distribution of Bolidophyceae was then assessed using environmental sequences available in public databases, as well as a large 18S rRNA V9 metabarcode data set from the Tara Oceans expedition. Bolidophyceans appear ubiquitous throughout the sampled oceans but always constitute a minor component of the phytoplankton community, corresponding to at most ~4% of the metabarcodes from photosynthetic groups (excluding dinoflagellates). They are ~10 times more abundant in the small size fraction (0.8–5 μm) than in larger size fractions. T. eleuthera sp. nov. constitutes the most abundant and most widespread operational taxonomic unit (OTU) followed by T. pacifica, T. mediterranea and the T. laevis clade. The T. mediterranea OTU is characteristic of Mediterranean Sea surface waters and the T. laevis clade OTU is most prevalent in colder waters, in particular off Antarctica.The ISME Journal advance online publication, 22 March 2016; doi:10.1038/ismej.2016.38. © 2016 International Society for Microbial Ecology

Hara K.,Prefectural University of Kumamoto | Zhang D.,Prefectural University of Kumamoto
Atmospheric Environment | Year: 2012

Transports of bacteria in the atmosphere relate to climate and global hydrological cycles by acting as nuclei of ice-cloud formation, and affect the ecosystems and public health in the downwind ecosystems. Here we present quantitative investigations of airborne bacterial cells coupled with LIVE/DEAD BacLight assay in southwestern Japan to show that airborne bacteria were widespread with Asian dust. Total bacterial cell-concentrations in dust varied between 1.0-×-10 6 and 1.6-×-10 7 cells m -3, which were one to two orders higher than those in non-dusty air and were correlated with the concentrations of aerosol particles larger than 1-μm. The ratio of viable bacterial cells to total bacterial cells (viability) of bacteria in dust ranged from 16 to 40%, which was quite smaller than the viability in non-dusty air. However viable bacterial cell concentrations in dust, 2.5-×-10 5---3.8-×-10 6 cells m -3, were similar to or higher than those in non-dusty air. Dust is thus a substantial source of airborne bacterial cells as well as mineral particles. These quantitative results suggest Asian dust is one of the processes for dispersal of airborne bacteria in the global atmosphere. © 2011 Elsevier Ltd.

Inoue A.,Prefectural University of Kumamoto
Journal of Forestry Research | Year: 2013

We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the mechanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens. © 2013 Northeast Forestry University and Springer-Verlag Berlin Heidelberg.

Aoki T.,Prefectural University of Kumamoto | Fukuoka Y.,Prefectural University of Kumamoto
Medicine and Science in Sports and Exercise | Year: 2010

Purpose: The maximum isometric force production capacity of the fingers decreases with age. However, little information is available on age-related changes in dynamic motor capacity of individual fingers. The purpose of this study was to compare the dynamic motor function of individual fingers between elderly and young adults using rapid single-finger and double-finger tapping. Methods: Fourteen elderly and 14 young adults performed maximum frequency tapping by the index, middle, ring, or little finger (single-finger tapping) and with alternate movements of the index-middle, middle-ring, or ring-little finger-pair (double-finger tapping). The maximum pinch force between the thumb and each finger, tactile sensitivity of each fingertip, and time taken to complete a pegboard test were also measured. Results: Compared with young subjects, the older subjects had significantly slower tapping rates in all fingers and finger-pairs in the tapping tasks. The age-related decline was also observed in the tactile sensitivities of all fingers and in the pegboard test. However, there was no group difference in the pinch force of any finger. The tapping rate of each finger did not correlate with the pinch force or tactile sensitivity for the corresponding finger in the elderly subjects. Conclusions: Maximum rate of finger tapping was lower in the elderly adults compared with the young adults. The decline of finger tapping ability in elderly adults seems to be less affected by their maximum force production capacities of the fingers as well as tactile sensitivities at the tips of the fingers. Copyright © 2010 by the American College of Sports Medicine.

Murata K.,Prefectural University of Kumamoto | Zhang D.,Prefectural University of Kumamoto
Atmospheric Environment | Year: 2014

Viable and non-viable bacteria in the air were investigated on the southwestern Japan coast to outline the manner by which bacteria were transported and to quantify the bacterial abundance and viability in the Northern Hemisphere westerly winds. The observations were conducted when the weather was governed by cyclones or anticyclones associated with Asian continent outflow between 12 October 2011 and 7 April 2013. Bacterial concentration in thermodynamically different air parcels was in the same order but different ranges: 4.5×105-1.3×106cellsm-3 in postfrontal air, 2.4×105-1.4×106cellsm-3 in prefrontal air, 5.4×105-9.9×105cellsm-3 in the air between cyclones and anticyclones and 2.9×105-4.1×105cellsm-3 in anticyclone air. In postfrontal air, the concentration correlated closely with coarse aerosol particles (diameter>1.0μm). In contrast, bacteria did not show a correlation with coarse particles in prefrontal air and anticyclone air. Bacterial viability was approximately 70% on average of all samples. However, the viability in postfrontal air was smaller than 60% if cases of stationary fronts with stagnant air were excluded. These results indicate that air parcels following fast-moving cold fronts in the westerly wind flow constantly and efficiently conveyed airborne bacteria from the Asian continent toward northwestern Pacific and the bacteria were characterized by coarse particle-correlated high abundance and low viability. The bacteria in slowly moving anticyclone and prefrontal air, characterized by low abundance and high viability, were more likely a mixture of long-range transported ones and regionally or locally originated ones. © 2014 Elsevier Ltd.

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