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Nishi-Tokyo-shi, Japan

The Tokyo University of Agriculture , abbreviated as Nodai or Tokyo nodai , is a private university which treats agriculture in Japan.The campus is in three places, Setagaya, Atsugi, and Okhotsk . Wikipedia.

Communication among microorganisms is mediated by secretion and detection of microbial signaling molecules such as quorum-sensing pheromones and microbial hormones. The molecules elicit the regulation of important genes necessary for microbial survival and often play important roles in interspecies or even inter-kingdom communication. Recent progress in the study of the signaling molecules has enabled us to eavesdrop on microbial conversations to gain insight on their intercellular communication system. This review summarizes the recent advances in the chemistry and chemical biology of these important microbial signaling molecules: acyl-homoserine lactones (AHLs), AI-2, CAI-1 related α-hydroxy ketones (AHKs), ComX pheromones, diffusible signal factors (DSFs), diffusible extracellular factor (DF), and Phytophthora mating hormones. © 2014 Elsevier Ltd. All rights reserved. Source

Hirose T.,Tokyo University of Agriculture
Oecologia | Year: 2011

Nitrogen use efficiency (NUE) was originally defined as the dry mass productivity per unit N taken up from soil. The term was subsequently redefined as the product of nitrogen productivity (NP) and mean residence time of nitrogen (MRT). However, this redefinition was found to contradict the original definition under certain conditions, and confusion arose when the MRT defined for a steady-state system was applied to a system that was actually not at steady state. As MRT is the expected length of time that a unit of N newly taken up from soil is retained before being lost, it can be translated into the plant nitrogen duration (PND) divided by the total N uptake. This MRT is determined equally well for a steady state- and a non-steady state system and is in accordance with the original definition of NUE. It can be applied to a herbaceous perennial stand (that was at a steady state) and to an annual stand (that was not at a steady state) to determine NUE. NUE is also applicable when plant growth and reproduction are analyzed in relation to N use. © 2011 Springer-Verlag. Source

Kameyama Y.,Tokyo University of Agriculture
American Journal of Botany | Year: 2012

Premise of the study: Cinnamomum camphora is an evergreen tree distributed in southern Japan, Taiwan, and southeastern China. Because of its vast utilization and cultivation, the natural distribution area of this species has been controversial. Methods and Results: I isolated and characterized 22 microsatellite loci in C. camphora. Levels of olymorphism were evaluated in 104 adult trees from three populations in Japan: Meiji Jingu (Shinto Shrine), Kajiya Plantation, and Manazuru Peninsula. The mean number of alleles per locus ranged from 4.1 to 8.0 among populations. The mean observed and expected heterozygosities per population ranged from 0.53 to 0.60 and 0.55 to 0.68, respectively. Conclusions: All of 22 loci showed a clear and strong single band for each allele, and revealed a useful degree of polymorphism. The microsatellite markers described here will be useful to study the history, population dynamics, mating system, and genetic structure of C. camphora. © 2012 Botanical Society of America. Source

Topographic niche differentiation (TND) is believed to facilitate the coexistence of tree species, but its effects are not well established for minor species or for life stages beyond recruitment. In this study, the effects of topography (slope inclination and topographic configuration) on the demographic parameters (mortality, diameter growth rate and recruitment rate) of both major and minor species in a species-rich temperate forest were examined using a mixed-model approach. The model selection analysis detected interspecies difference in the response of recruitment rate to topographic configuration. However, mortality and diameter growth rate of stems with DBH ≥ 5 cm did not show any species-specific response to two topographic parameters. The recruitment rate of major species tended to be higher under topographic conditions where many stems of the species already existed, suggesting significant habitat segregation. No such correlation was found for minor species. These results suggest TND has a limited effect on habitat segregation among species, and that other mechanisms also contributed to coexistence, especially when considering minor species. © 2010 The Ecological Society of Japan. Source

Hirose T.,Tokyo University of Agriculture
Oecologia | Year: 2012

Nitrogen use efficiency (NUE) has been widely used to study the relationship between nitrogen uptake and dry mass production in the plant. As a subsystem of plant nitrogen use efficiency (NUE), I have defined leaf-level NUE as the surplus production (gross production minus leaf respiration) per unit amount of nitrogen allocated to the leaf, with factorization into leaf nitrogen productivity (NP) and mean residence time of leaf nitrogen (MRT). These concepts were applied to two herbaceous stands: a perennial Solidago altissima stand and an annual Amaranthus patulus stand. S. altissima had more than three times higher leaf NUE than A. patulus due to nearly three times longer MRT of leaf N. In both species, NUE and NP were higher at the leaf level than at the plant level, because most leaf N is involved directly in the photosynthetic activity and because leaf surplus production is higher than the plant net production. MRT was longer at the plant level. The more than twice as long MRT at the plant level as at the leaf level in S. altissima was due to a large contribution of nitrogen storage belowground in the winter in this species. Thus, comparisons between a perennial and an annual system and between plant- and leaf-level NUE with their components revealed the importance of N allocation, storage, recycling, and turnover of organs for leaf photosynthetic production and plant dry mass growth. © 2011 Springer-Verlag. Source

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