Publications by authors named "Katsuhara M"

In the cells of Chara corallina, permeant monohydric alcohols including methanol, ethanol and 1-propanol increased the hydraulic resistance of the membrane (Lp). We found that the relative value of the hydraulic resistance (Lp) was linearly dependent on the concentration (C) of the alcohol. The relationship is expressed in the equation: Lp = ρC + 1, where ρ is the hydraulic resistance modifier coefficient of the membrane.

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We have developed a novel composite filler with Poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonic acid) (PEDOT:PSS), a biocompatible organic conductive polymer, adsorbed on carbon particles for biological electrodes. This composite filler enables to fabricate high-performance biological electrodes simply by adding it to resin in the same way as conventional conductive fillers. The fabricated electrodes achieve ion exchange properties similar to those of PEDOT:PSS polymers and therefore low skin and electrode contact impedance.

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High urinary levels of dialkylphosphates (DAPs), which are common structures of organophosphate pesticides (OPs), have been associated with several adverse health outcomes in human biomonitoring studies. Previous studies have indicated that dietary OP exposure and ingestion of environmentally degraded DAP, which is inactive with acetylcholinesterase, can lead to an increase in urinary DAP levels in the general population. However, the specific food sources contributing to the intake of OPs and DAPs have not been identified.

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HAK family transporters primarily function as K+ transporters and play major roles in K+ uptake and translocation in plants, whereas several HAK transporters exhibit Na+ transport activity. OsHAK2, a rice HAK transporter, was shown to mediate Na+ transport in Escherichia coli in a previous study. In this study, we investigated whether OsHAK2 is involved in Na+ transport in the rice plant.

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The hydraulic resistance (the reciprocal of the hydraulic conductivity Lp) Lp was measured in cells of Chara corallina by the method of transcellular osmosis. Treatment of cells with 100 mM KCl decreased Lp significantly. Subsequent treatment of the cells with 70 mM CaCl recovered the decreased Lp to the original value.

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K+/Na+ homeostasis is important for land plants, particularly under salt stress. In this study, the structure and ion transport properties of the high-affinity K+ transporter (HKT) of the liverwort Marchantia polymorpha were investigated. Only one HKT gene, MpHKT1, was identified in the genome of M.

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Increased levels of dialkylphosphates (DAP) in maternal urine are associated with a variety of adverse developmental outcomes in children. Although urinary DAP levels are usually considered to be a marker of exposure to organophosphate (OP) pesticides, excretion of DAP may also increase by ingesting preformed DAP. To date, no study has quantitatively assessed the possible contribution of the dietary intake of preformed DAP and OP pesticides to urinary levels of DAP.

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Article Synopsis
  • The study identifies five mRNA variants of the high-affinity K transporter in japonica rice, focusing on their expression and roles under salt stress.
  • Analysis showed the main variant had significantly higher transcript levels in roots and shoots compared to others, particularly after 24 hours of salt exposure.
  • Two-electrode voltage clamp experiments indicated that the variants expressed in oocytes resulted in smaller sodium currents, contributing to insights on ion homeostasis and salt tolerance in rice.
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Aluminum (Al)-tolerant tobacco cell line ALT301 derived from SL (wild-type) hardly exhibits Al-triggered reactive oxygen species (ROS) compared with SL. Molecular mechanism leading to this phenotype was investigated comparatively with SL. Under normal growth condition, metabolome data suggested the activation of glycolysis and lactate fermentation but the repression of the tricarboxylic acid (TCA) cycle in ALT301, namely aerobic fermentation, which seemed to be transcriptionally controlled partly by higher expression of genes encoding lactate dehydrogenase and pyruvate dehydrogenase kinase.

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It is my pleasure to be writing this editorial as Editor-in-Chief of the Journal of Plant Research (JPR) for the next 4 years, following the former Editor-in-Chief, Prof. Kouki Hikosaka of Tohoku University. I will do my best to improve JPR along with all editors, board members, and readers.

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Hydraulic resistances (reciprocals of hydraulic conductivities) of the cell (Lp), the cell wall (Lp), the membrane (Lp), the plasma membrane (Lp), and the tonoplast (Lp) were determined in individual internodal cells of Chara corallina and their dependence on the cell age was studied. The thickness of the cell wall (d) was adopted as an index of the cell age, since the cell wall of spring-grown young cells (sg-cells) was found to be significantly thinner than that of winter-spent old cells (ws-cells). Both Lp and Lp were found to increase with cell age.

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Plant plasma membrane-type plasma membrane intrinsic protein (PIP) aquaporins are classified into two groups, PIP1s and PIP2s. In this study, we focused on HvPIP1;2, a PIP1 in barley (Hordeum vulgare), to dissect the molecular mechanisms that evoke HvPIP1-mediated water transport. No HvPIP1;2 protein was localized to the plasma membrane when expressed alone in Xenopus laevis oocytes.

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Some plasma membrane intrinsic protein (PIP) aquaporins can facilitate ion transport. Here we report that one of the 12 barley PIPs (PIP1 and PIP2) tested, , facilitated cation transport when expressed in oocytes. -associated ion currents were detected with Na and K, but not Cs, Rb, or Li, and was inhibited by Ba, Ca, and Cd and to a lesser extent Mg, which also interacted with Ca.

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We characterized an Na transporter SvHKT1;1 from a halophytic turf grass, . SvHKT1;1 mediated inward and outward Na transport in oocytes and did not complement K transporter-defective mutant yeast. SvHKT1;1 did not complement mutant , suggesting its distinguishable function from other typical HKT1 transporters.

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in rice, belongs to the high-affinity K Transporter family, has been found to be involved in salt tolerance. in rice (Nipponbare) produces mRNA variants, but their functions remain elusive. In salt tolerant rice, Pokkali, eight variants (V1-V8) were identified in addition to the full-length (FL) cDNA.

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Plasma membrane intrinsic proteins (PIPs) are known to be major facilitators of the movement of a number of substrates across cell membranes. From a drought-resistant cultivar of Oryza sativa (rice), we isolated an OsPIP1;3 gene single-nucleotide polymorphism (SNP) that is mostly expressed in rice roots and is strongly responsive to drought stress. Immunocytochemistry showed that OsPIP1;3 majorly accumulated on the proximal end of the endodermis and the cell surface around the xylem.

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In the analysis of pesticides performed with gas chromatography, the quantitative performance of measurements can be severely compromised by phenomena known as matrix effects. In seeking a solution to the problem of matrix effects, the application of a modifier gas generator (MGG) was investigated in this study, together with analyte protectants and multiple internal standards. Ethylene glycol (EG) was used as modifier gas and matrix effects in GCMS analysis were then evaluated by using the extracts of various food commodities.

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Article Synopsis
  • - Sporobolus virginicus is a salt-tolerant grass found globally, with a specific Japanese variant capable of thriving in salt conditions three times saltier than seawater.
  • - Researchers generated 3500 transgenic Arabidopsis lines using cDNA from S. virginicus and identified 10 lines with improved salt tolerance, including those containing glycine-rich RNA-binding proteins (SvGRP1 and SvGRP2).
  • - Analysis of these transgenic plants showed that SvGRP1 enhances salt tolerance by altering specific metabolic pathways and increasing certain acid levels, shedding light on the potential role of GRPs in helping plants survive salinity stress.
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Class II high-affinity potassium transporters (HKTs) have been proposed to mediate Na+-K+ co-transport in plants, as well as Na+ and K+ homeostasis under K+-starved and saline environments. We identified class II HKTs, namely SvHKT2;1 and SvHKT2;2 (SvHKTs), from the halophytic turf grass, Sporobolus virginicus. SvHKT2;2 expression in S.

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A strain of lactic acid bacteria, designated NtB2, isolated from the gut of the wood-feeding higher termite Nasutitermes takasagoensis, was characterized genetically and phenotypically. Strain NtB2 was related to Lactococcus lacti subsp. tructae JCM 31125 isolated from brown trout, showing 93.

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Cyclic nucleotide-gated channels (CNGCs) have been postulated to contribute significantly in plant development and stress resistance. However, their electrophysiological properties remain poorly understood. Here, we characterized barley CNGC2-3 (HvCNGC2-3) by the two-electrode voltage-clamp technique in the oocyte heterologous expression system.

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