Adsorption of humic acid on goethite: Isotherms, charge adjustments and potential profiles
Saito, T. ; Koopal, L.K. ; Riemsdijk, W.H. van; Nagasaki, S. ; Tanaka, S. - \ 2004
Langmuir 20 (2004)3. - ISSN 0743-7463 - p. 689 - 700.
natural organic-matter - oxide-water interface - metal-ion binding - donnan model parameters - fulvic-acid - iron-oxide - polyelectrolyte adsorption - weak polyelectrolytes - humate interactions - surface ionization
The adsorption of natural organic matter (NOM) on mineral (hydr)oxide plays an important role in the evaluation of the speciation of toxic metal ions in the environment. Because both NOM and mineral oxide have variable charges that adjust upon adsorption, a good understanding of proton binding is required before the binding of metal ions can be understood. In this study, the adsorption of purified Aldrich humic acid (PAHA) on goethite was examined as a function of the environmental conditions (pH, salt concentration, and free concentration of PAHA) together with the proton adsorption to PAHA, goethite, and their mixtures. The induced charges on both components were separated on the basis of the difference between the charge/pH curves of the mixture and those of the single components. The electrostatic potential profile across the adsorbed layer was obtained as a numerical solution of the Poisson-Boltzmann equation using the charge density of the adsorbed PAHA and the goethite surface. From the quantitative evaluation of the induced charge on both components, it is revealed that the degree of the charge adjustment is related to the electrostatic affinity between the PAHA segments and the goethite surface, the electrostatic repulsion between the PAHA segments, and the electrostatic shielding by salt ions. Considering the charge distribution of the adsorbed PAHA at the goethite surface, it is concluded that the change of the charge adjustment is sensitive to that of the conformation of the adsorbed PAHA. From the detailed inspection of the assumptions made and the comparison with the reported theoretical calculations, the obtained potential profiles are considered to broadly reflect the true potential profiles. Because a charge adjustment is not frequently considered in detail in relation to the NOM adsorption on metal (hydr)oxides, the obtained results can form the basis for the further development of modeling of the adsorption of NOM on (hydr)oxide surfaces.
Monolithic silica-based capillary reversed-phase liquid chromatography/electrospray mass spectrometry for plant metabolomics
Tolstikov, V.V. ; Lommen, A. ; Nakanishi, K. ; Tanaka, N. ; Fiehn, O. - \ 2003
Analytical Chemistry 75 (2003)23. - ISSN 0003-2700 - p. 6737 - 6740.
functional genomics - polar compounds - ionization - columns - identification - validation - efficiency - flavonoids
Application of C18 monolithic silica capillary columns in HPLC coupled to ion trap mass spectrometry detection was studied for probing the metabolome of the model plant Arabidopsis thaliana. It could be shown that the use of a long capillary column is an easy and effective approach to reduce ionization suppression by enhanced chromatographic resolution. Several hundred peaks could be detected using a 90-cm capillary column for LC separation and a noise reduction and automatic peak alignment software, which outperformed manual inspection or commercially available mass spectral deconvolution software.
The stacked flavin adenine dinucleotide conformation in water is fluorescent on picosecond timescale.
Chosrowjan, H. ; Taniguchi, S. ; Mataga, N. ; Tanaka, F. ; Visser, A.J.W.G. - \ 2003
Chemical Physics Letters 378 (2003). - ISSN 0009-2614 - p. 354 - 358.
time-resolved fluorescence - nuclear magnetic-resonance - protein nanospace - electron-transfer - dynamics - flavoproteins - spectroscopy - chromophores - proton
The fluorescence upconversion technique has been applied to examine the picosecond fluorescence decay kinetics of flavin adenine dinucleotide (FAD) in aqueous solution. In the observation range of 30 ps three fluorescent lifetimes can be distinguished. The shortest-lived component (similar to1 ps) arises from water relaxation around the excited flavin. The 9-ps component originates from the intramolecular complex between flavin and adenine, whereas the nanosecond decay is attributed to the unstacked form of FAD. The spectra of the three forms are derived from global analysis of decay curves at different emission wavelengths and time regimes using a triple exponential function. It is assumed that the amplitude belonging to the nanosecond fluorescence component reflects the steady-state fluorescence spectrum. Fluorescence anisotropy to its maximum value of 0.4 is instantaneously created. (C) 2003 Elsevier B.V. All rights reserved.
Binding site of novel 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine herbicides in the D1 protein of Photosystem II
Ikeda, Y. ; Ohki, S. ; Koizumi, K. ; Tanaka, A. ; Watanabe, H. ; Kohno, H. ; Rensen, J.J.S. van; Böger, P. ; Wakabayashi, K. - \ 2003
Photosynthesis Research 77 (2003). - ISSN 0166-8595 - p. 35 - 43.
photosynthetic electron-transport - chloroplasts - inhibition - derivatives - resistant
A series of replacement experiments of [C-14]-triazines, [C-14]-atrazine and [7-C-14]-2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine, bound to thylakoids isolated from wild-type and atrazine-resistant Chenopodium album (lambsquarters) were conducted. Replacement experiments of [C-14]-triazines bound to wild-type Chenopodium thylakoids with non-labeled atrazine and 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine were carried out, to elucidate whether benzylamino-1,3,5-triazines use the same binding niche as atrazine. [C-14]-Atrazine and [7-C-14]-2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine bound to wild-type thylakoids were replaced by non-labeled 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine and non-labeled atrazine, respectively. The above two replacements showed mutual competition. To clarify further whether benzylamino-1,3,5-triazines bind at the D1-protein to amino acid residue( s) different from atrazine or not, experiments to replace [7-C-14]-2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazines bound to atrazine-resistant Chenopodium thylakoids by non-labeled atrazine, 2-(4-bromobenzylamino)-4-methyl-6-trifluoromethyl-1,3,5-triazine, DCMU and DNOC were carried out. Although the bound [7-C-14]-2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine was difficult to be replaced even with high concentrations of atrazine, [C-14]-labeled 1,3,5-triazine was competitively replaced by non-labeled 2-(4-bromobenzylamino)-4-methyl-6-trifluoromethyl-1,3,5-triazine, DCMU or DNOC. Thus, 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine herbicides are considered to bind to the same niche at the D1 protein as atrazine, but use amino acid residue(s) different from those involved with atrazine binding.
A transcriptional activator, AoXlnR, controls the expression of genes encoding xylanolytic enzymes in Aspergillus oryzae
Marui, J. ; Tanaka, A. ; Mimura, S. ; Graaff, L.H. de; Visser, J. ; Kitamoto, N. ; Kato, M. ; Kobayashi, T. ; Tsukagoshi, N. - \ 2002
Fungal Genetics and Biology 35 (2002)2. - ISSN 1087-1845 - p. 157 - 169.
taka-amylase-a - zinc binuclear cluster - shoyu koji mold - molecular-cloning - escherichia-coli - sequence-analysis - beta-xylosidase - reductase gene - xylanase genes - amino-acid
By deletion across the promoter region of the xynF1 gene encoding the major Aspergillus oryzae xylanase, a 53-bp DNA fragment containing the XlnR binding sequence GGCTAAA as well as two similar sequences was shown to confer xylan inducibility on the gene. Complementary and genomic DNAs encoding the Aspergillus niger xlnR homologous gene, abbreviated AoxlnR, were cloned from A. oryzae and sequenced. AoXlnR comprised 971 amino acids with a zinc binuclear cluster domain at the N-terminal region and revealed 77.5% identity to the A. niger XlnR. Recombinant AoXlnR protein encompassing the zinc cluster region of the N-terminal part bound to both the consensus binding sequence and its cognate sequence, GGCTGA, with an approximately 10 times lower affinity. GGCTA/GA is more appropriate as the XlnR consensus binding sequence. Both sequences functioned independently in vivo in XlnR-mediating induction of the xynF1 gene. This was further confirmed by using an AoxlnR disruptant. Neither the xynF1 nor the xylA gene was expressed in the disruptant, suggesting that the xylan-inducible genes in A. oryzae may also be controlled in the same manner as described for A. niger
|Treatment of waste activated sludge by thermophylic acidifying UASB reactor
Tanaka, Y. ; Sanders, W.T.M. ; Zeeman, G. - \ 1999
Japanese Journal of Water Treatment Biology 35 (1999)1. - p. 9 - 18.
Light climate and growth in shade-tolerant Fagus crenata, Acer mono and Carpinus cordata.
Peters, R. ; Hiroshi Tanaka, ; Mitsue Shibata, ; Tohru Nakashizuka, - \ 1995
Ecoscience 2 (1995). - ISSN 1195-6860 - p. 67 - 74.
|The effect of high temperature in long days on the floral induction of the short-day plant, Perilla crispa (Thunp.) Tanaka.
Wellensiek, S.J. - \ 1987
Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen. Serie C: Biological and medical sciences 90 (1987). - ISSN 0023-3374 - p. 231 - 238.