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Nishizaki Y.,Tokyo University of Agriculture and Technology | Sasaki N.,Tokyo University of Agriculture and Technology | Yasunaga M.,Tokyo University of Agriculture and Technology | Miyahara T.,Tokyo University of Agriculture and Technology | And 4 more authors.
Journal of Experimental Botany | Year: 2014

In delphiniums (Delphinium grandiflorum), blue flowers are produced by the presence of 7-polyacylated anthocyanins. The polyacyl moiety is composed of glucose and p-hydroxybenzoic acid (pHBA). The 7-polyacylation of anthocyanin has been shown to be catalysed by two different enzymes, a glucosyltransferase and an acyltransferase; both enzymes utilize p-hydroxybenzoyl-glucose (pHBG) as a bi-functional (Zwitter) donor. To date, however, the enzyme that synthesizes pHBG and the gene that encodes it have not been elucidated. Here, five delphinium cultivars were investigated and found to show reduced or undetectable 7-polyacylation activity; these cultivars synthesized delphinidin 3-O-rutinoside (Dp3R) to produce mauve sepals. One cultivar showed a deficiency for the acyl-glucose-dependent anthocyanin 7-O-glucosyltransferase (AA7GT) necessary for mediating the first step of 7-polyacylation. The other four cultivars showed both AA7GT activity and DgAA7GT expression; nevertheless, pHBG accumulation was significantly reduced compared with wild-type cultivars, whereas p-glucosyl-oxybenzoic acid (pGBA) was accumulated. Three candidate cDNAs encoding a UDP-glucose-dependent pHBA glucosyltransferase (pHBAGT) were identified. A phylogenetic analysis of DgpHBAGT amino acid sequences showed a close relationship with UGTs that act in acyl-glucose synthesis in other plant species. Recombinant DgpHBAGT protein synthesized pHBG and had a high preference for pHBA in vitro. Mutant cultivars accumulating pGBA had very low expression of DgpHBAGT, whereas expression during the development of sepals and tissues in a wild cultivar showed a close correlation to the level of accumulation of pHBG. These results support the conclusion that DgpHBAGT is responsible for in vivo synthesis of pHBG in delphiniums. © 2014 The Author. Source

Irie K.,Ehime University | Kawaguchi M.,Ehime University | Mizuno K.,Ehime Research Institute of Agriculture | Song J.-Y.,Ehime University | And 3 more authors.
Marine Pollution Bulletin | Year: 2011

Heavy oil (HO) on the sea surface penetrates into fish eggs and prevents the normal morphogenesis. To identify the toxicological effects of HO in the context of the egg types, we performed exposure experiments using floating eggs and sinking eggs. In the course of development, HO-exposed embryos of floating eggs showed abnormal morphology, whereas early larva of the sinking eggs had almost normal morphology. However, the developing peripheral nervous system of sinking eggs showed abnormal projections. These findings suggest that HO exposed fishes have problems in the developing neurons, although they have no morphological malformations. Through these observations, we conclude that HO is strongly toxic to floating eggs in the morphogenesis, and also affect the neuron development in both floating and sinking eggs. © 2011 Elsevier Ltd. Source

Kadowaki K.,Ehime University | Kurisaka N.,Ehime Research Institute of Agriculture
IEEJ Transactions on Fundamentals and Materials | Year: 2013

This paper presents an experimental study on control of germination for Arabidopsis seed with a barrier discharge produced by polarity-reversed voltage pulses. 100 ns-width polarity-reversed pulses are applied to the seeds between plane electrodes covered by glass barriers. The electrode configuration allows the barrier discharge propagation along the seed surface at a relatively low voltage. After the discharge treatment, the seeds are incubated for 2 or 3 days to measure the germination rate. Relationships between the cumulative input energy density into plasma and the germination rate are investigated. Germination rate is significantly reduced by 20 J/cm3. However, it increases when the cumulative energy density is up to 50 J/cm3 and then it decreases again by the further energy input. These results propose a superposition of two effects, stimulation and inhibition, of the discharge treatment on the germination of Arabidopsis seed. Results of evans-blue dyeing for the discharge-exposed seeds indicate that necrosis of the seed coat is caused by the discharge treatment. © 2013 The Institute of Electrical Engineers of Japan. Source

Kawanishi R.,Ehime University | Inoue M.,Ehime University | Takagi M.,Ehime University | Miyake Y.,Ehime University | Shimizu T.,Ehime Research Institute of Agriculture
Ichthyological Research | Year: 2011

We examined habitat factors related to the distribution and abundance of the spinous loach Cobitis shikokuensis, an endangered benthic fish, in the Shigenobu River system, southwestern Japan. In the study river, the spinous loach was distributed widely along the main stem, from headwater to near the mouth, whereas it was rarely found in tributary streams. Classification tree analysis showed that the presence/absence of spinous loach was explained by a combination of percent pebble and length of river fragment between artificial barriers. Spinous loach incidence was high in sites with abundant pebble (>27.7%), but low in sites with short river fragment (≤0.97 km) even if pebbles were abundant. A regression tree model for loach density retained only percent pebble as a single best predictor, with sites with higher percent pebble (>40.4%) having higher density. These results suggest that substrate condition is an important factor determining the distribution and abundance of spinous loach and also that habitat fragmentation by artificial barriers has great potential to threaten the spinous loach population in this river. Considering the highly fragmented situation of the study river and prevention of upstream migration by barriers, we conclude that maintenance of suitable habitats in upper reaches has high priority for conservation of the spinous loach. © 2011 The Ichthyological Society of Japan. Source

Nishi S.,Hiroshima University | Yamashita H.,Ehime Research Institute of Agriculture | Kawato Y.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Nakai T.,Hiroshima University
Applied and Environmental Microbiology | Year: 2016

Piscine nodavirus (betanodavirus) is the causative agent of viral nervous necrosis (VNN) in a variety of cultured fish species, particularly marine fish. In the present study, we developed a sensitive method for cell culture isolation of the virus from seawater and applied the method to a spontaneous fish-rearing environment. The virus in seawater was concentrated by an iron-based flocculation method and subjected to isolation with E-11 cells. A real-time reverse transcriptase PCR (RT-PCR) assay was used to quantify the virus in water. After spiking into seawater was performed, a betanodavirus strain (redspotted grouper nervous necrosis virus [RGNNV] genotype) was effectively recovered in the E-11 cells at a detection limit of approximately 105 copies (equivalent to 102 50% tissue culture infective doses [TCID50])/liter seawater. In an experimental infection of juvenile sevenband grouper (Epinephelus septemfasciatus) with the virus, the virus was isolated from the drainage of a fish-rearing tank when the virus level in water was at least approximately 105 copies/liter. The application of this method to sevenband grouper-rearing floating net pens, where VNN prevailed, resulted in the successful isolation of the virus from seawater. No differences were found in the partial sequences of the coat protein gene (RNA2) between the clinical virus isolates of dead fish and the cell-cultured virus isolates from seawater, and the viruses were identified as RGNNV. The infection experiment showed that the virus isolates from seawater were virulent to sevenband grouper. These results showed direct evidence of the horizontal transmission of betanodavirus via rearing water in marine aquaculture. © 2016, American Society for Microbiology. All Rights Reserved. Source

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