Ichinomiya M.,Prefectural University of Kumamoto
ISME Journal | Year: 2016
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
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.
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.
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.
Zushi K.,Shokei College |
Matsuzoe N.,Prefectural University of Kumamoto
Journal of the Japanese Society for Horticultural Science | Year: 2012
L-ascorbate (ASA; a reduced form of vitamin C) and glutathione (GSH) in tomato fruit participate in many diverse biological processes such as fruit ripening. In general, ASA and GSH are regulated by the reactive oxygen species scavenging system (antioxidant system). The tomato is a complex fruit composed of skin, pericarp walls, placenta, locular tissue, and seed tissues, and it is unclear whether the antioxidant contents and systems differ among these tissues. The aim of this study is to clarify tissue-specific changes in oxidative parameters, antioxidant contents, and antioxidant enzymes during fruit ripening in the tomato pericarp (skin, pericarp walls) and pulp (placenta, locular tissue, seeds). Lipid peroxidation and the H 2O 2 content remained constant during fruit ripening and were lower in the pulp than in the pericarp. In addition, ASA and GSH contents were the same in both these tissues when the fruits were picked at the red stage; however, changes in the superoxide dismutase, catalase, and ASA-GSH cycles, related to enzymes such as ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase, showed tissue-specific differences during ripening. These results indicate that ASA and GSH contents in both tissues are the same when fruits are picked at the red stage, but oxidative parameters and antioxidant systems show tissue-specific differences during fruit ripening. Furthermore, our results indicate that oxidative stress in the pulp was lower than that in the pericarp. This work therefore provides a basis for understanding the role of antioxidant systems during tomato fruit ripening. © 2012.