Accelerated aromatic compounds degradation in aquatic environment by use of interaction between Spirodela polyrrhiza and bacteria in its rhizosphere

Accelerated degradation of organic chemicals by aquatic plant-bacterial associations was reported for the first time with elucidation of the role and contribution of aquatic plant and bacteria in its rhizosphere using a fast-growing giant duckweed, Spirodela polyrrhiza. The results clearly showed the accelerated degradation of all the three aromatic compounds (phenol, aniline and 2,4-dichlorophenol [2,4-DCP]) tested by aquatic plant-bacterial associations. In phenol degradation system, phenol-degrading bacteria indigenous to the rhizosphere fraction of S. polyrrhiza mainly contributed, while in aniline degradation system S. polyrrhiza mainly contributed by stimulating aniline-degrading bacteria both in the rhizosphere and balk water fraction. On the other hand in 2,4-DCP degradation system, S. polyrrhiza itself mainly contributed to its removal by uptake and degradation. Thus, the mechanisms for accelerated removal of aromatic compounds were quite different depending on the substrates. S. polyrrhiza showed selective accumulation of phenol-degrading bacteria in its rhizosphere fraction, while aniline- and 2,4-DCP-degrading bacteria were not much accumulated. S. polyrrhiza secreted peroxidase and laccase. However, both of the enzymatic activities increased with the addition of aromatic compounds, degrading ability of S. polyrrhiza itself should be owing to the production of peroxidase rather than laccase because the change of peroxidase activity and concentration of each aromatic compound well concurred. From the results obtained in the present study, it can be concluded that the feasibility of the use of aquatic plant-bacterial associations to accelerate the degradation of organic chemicals especially recalcitrant compounds in aquatic environment was shown.     

Catechol siderophore excretion by magnetotactic bacterium Magnetospirillum magneticum AMB-1

Siderophore activity was detected in the culture supernatant of the magnetotactic bacterium Magnetospirillum magneticum AMB-1. Here we report the first structural elucidation of a siderophore produced by a magnetotactic bacterium. The structure of the purified compound was 3,4-dihydroxybenzoic acid as determined by nuclear magnetic resonance (NMR) and electro-spray ionization mass spectroscopy (ESI-MS).     

Ultrahigh-resolution immunofluorescence microscopy using ultrathin cryosections: subcellular distribution of caveolin-1alpha and CD31 in human placental endothelial cells

We compared the z-axis resolutions achieved by immunofluorescence (IF) microscopic imaging of tissue sections of different thicknesses (ultrathin cryosections, optical sections of cryostat sections and conventional cryostat sections). We used these images to determine the distribution of caveolin-1alpha (CAV-1alpha) and CD31 in endothelial cells of full-term, human placenta. Anti-CAV-1alpha antibody was used to visualize caveolae, which are among the smallest organelles. By using ultrathin cryosections as substrates for IF microscopy, we were able to resolve discrete caveolae that were primarily present immediately beneath the endothelial cell surface. In contrast, neither conventional nor confocal images from cryostat sections were able to resolve individual caveolae, despite dramatic reductions in the confocal image degradation that arises from out-of-focus fluorescence signals. Anti-CD31 antibody labeled the endothelial cell surface exclusively. Quantitative analysis of ultrathin cryosections showed that about 2.5 times more CD31 was expressed on the luminal surface of cells than on the abluminal surface. Our results demonstrate that ultrathin cryosections can serve as excellent substrates for ultrahigh-resolution IF microscopy.     

Enzymatic preparation of hollow magnetite microspheres for hyperthermic treatment of cancer

Ferrimagnetic materials can be expected to be useful as thermal seeds for hyperthermic treatment of cancer, especially where the cancer is located in deep parts of body, as they can generate heat by magnetic hysteretic loss when they are placed in an alternating magnetic field. In this study, hollow magnetite (Fe₃O₄) particles were prepared using an enzymatic reaction of urease. A hollow particle was obtained by using a Pasteur pipette. The particle was 500 μm in size and was composed of Fe₃O₄. Its saturation magnetization and coercive force were 57 emu⋅g⁻¹ and 183 Oe, respectively. Its heat generation under an alternating magnetic field of 300 Oe at 100 kHz was estimated to be 45 W⋅g⁻¹. Microspheres 30 μm in diameter were also successfully obtained by using a spray gun.     

Preparation and Characterization of Hybrid Chitosan/Acrylic Resin Emulsions and Their Films

Summary: Solutions containing chitosan of different molecular weights and several acidic monomers were prepared under various aging conditions. Hybrid chitosan/acrylic resin emulsions were prepared from these solutions by emulsion polymerization. The viscosities of the hybrid chitosan/acrylic resin emulsions were influenced significantly by the molecular weight of chitosan, the acidic monomer used, and the aging conditions. DSC and FT‐IR spectroscopy of the hybrid chitosan/acrylic resin films indicated that chitosan was well distributed in the films. The water absorption and formaldehyde adsorption abilities of the acrylic resin films prepared with chitosan were higher than the corresponding films prepared without chitosan, and they increased with increasing molecular weight of the chitosan. The morphology of these films, studied by TEM, revealed that the distribution of chitosan in the hybrid chitosan/acrylic resin emulsion was dependent on the molecular weight of chitosan, the acidic monomer used, and the aging conditions.

Chitosan salts with acrylic acid (R = ? CH?CH₂), methacrylic acid (R = ? C(CH₃)?CH₂) and itaconic acid (R = ? CH₂(COOH)C?CH₂).     

Analysis of disulfoton sulfoxide in chingentsuai by pulsed splitless mass spectrometry using programmed temperature vaporization (PTV) inlet

A peak considered to be due to disulfoton sulfoxide as a metabolite of disulfoton was detected in the analysis of the chingentsuai extraction solution of vegetables by GC-FPD. In the analysis by GC/MS for identification, though the retention time and the mass spectrum were the same as those of the standard, the spectrum was different from MS library data. It appeared that decomposition of disulfoton sulfoxide occurred at the inlet. Therefore, we used a programmed temperature vaporization (PTV) inlet in the pulsed splitless mode to achieve a low inlet temperature and high injection pressure. As a result, the expected mass spectrum of disulfoton sulfoxide was obtained. Under this condition, the peak obtained from chingentsuai was identified as disulfoton sulfoxide. Disulfoton sulfoxide was detected from 2 of 25 chingentsuai samples, at concentrations of 0.66 microg/g and 0.14 microg/g.     

Selective adsorption of biladien-ab-one and zinc biladien-ab-one to mesoporous silica

The adsorption of linear tetrapyrroles and porphyrins to mesoporous silicas with pore diameters of 2.3, 2.7, 4.0, and 7.0 nm from a benzene solution was investigated. As linear tetrapyrroles, 1,15,21,22-tetrahydro-19-benzoyl-5,10,15-triphenyl-15-hydroxybilin-1-one (biladien-ab-one, 1a), its zinc complexes (2 and 3), 1,15,21,22-tetrahydro-19-(4-hexyloxybenzoyl)-5,10,15-tri(4-hexyloxy)phenyl-15-hydroxybilin-1-one (C6-biladienone, 1b), 1,15,21,22-tetrahydro-19-(4-nonyloxybenzoyl)-5,10,15-tri(4-nonyloxy)phenyl-15-hydroxybilin-1-one (C9-biladienone, 1c), 1,15, 21,22-tetrahydro-19-(4-dodecyloxybenzoyl)-5,10,15-tri(4-dodecyloxy)phenyl-15-hydroxybilin-1-one (C12-biladienone, 1d), and 1,15,21,22-tetrahydro-19-(3,5-didodecyloxybenzoyl)-5,10,15-tri(3, 5-di-dodecyloxy)phenyl-15-hydroxybilin-1-one (1e) were employed. As porphyrins, 5,10,15,20-tetraphenylporphyrin (4a) and 5,10,15,20-tetra(4-methoxyphenyl)porphyrin (4b) were used. The isothermal adsorption curves were determined, showing that the amount of adsorption decreases in the order, 1a > 1b > 1c > 1d > 2, while neither 1e, 4a, nor 4b were adsorbed to mesoporous silicas. Mesoporous silica with the diameter of 4.0 nm adsorbed the largest amounts of biladienones. The adsorption was not observed in THF, acetone or ethanol. Neither 1c nor 1d was adsorbed to mesoporous silica with the pore diameter of 2.3 nm. These results indicate that the absorption is driven by polar interactions such as hydrogen bonding, and size exclusion effects are observed even for a molecule with flexible alkyl chains. The amount of adsorbed biladienone increased as the temperature was raised from 25 to 35 °C. The adsorption of biladien-ab-ones at 80 °C caused dehydration of biladien-ab-one to bilatrien-abc-one due to the acidity of the mesoporous silica.     

Free Fatty Acid Derivative HUHS2002 Potentiates α7 ACh Receptor Responses Through Indirect Activation of CaMKII

The present study examined the effect of 4-[4-(Z)-hept-1-enyl-phenoxy] butyric acid (HUHS2002), a free fatty acid derivative, on α7 acetylcholine (ACh) receptor responses. HUHS2002 potentiated whole-cell membrane currents through α7 ACh receptors expressed in Xenopus oocytes in a concentration (1–100 nM)-dependent manner, reaching about 140 % of the original amplitude at 100 nM 50 min after a 10-min treatment. The HUHS2002 effect was prevented by KN-93, an inhibitor of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), while it was not affected by GF109203X, an inhibitor of protein kinase C (PKC), or H-89, an inhibitor of protein kinase A (PKA). In the in situ CaMKII assay using cultured rat hippocampal neurons, HUHS2002 activated CaMKII and the activation was abolished by KN-93. In the cell-free assay of protein phosphatase 1 (PP1), HUHS2002 partially inhibited PP1 activity. Taken together, these results indicate that HUHS2002 potentiates α7 ACh receptor responses by indirectly activating CaMKII, possibly via inhibition of PP1.     

Microstructural Change of Ni–GDC Cermet Anode in the Electrolyte‐supported Disk‐type SOFC upon Daily Start‐up and Shout‐down Operations

The daily start‐up and shut‐down operations were carried out for the 1 kW‐class solid oxide fuel cell stack composed of 46 electrolyte‐supported disk‐type planar cells made by Mitsubishi Materials Corporation and Kansai Electric Power Company. The representative Ni–gadolinia doped ceria cermet anodes in the deteriorated cells were analyzed by the dual‐beam focused ion beam‐scanning electron microscope. The anode microstructures were reconstructed and the microstructural parameters such as triple phase boundary (TPB) length were quantified. The surface area of nickel phase decreased with an increase in the deterioration rate, leading to a reduction in the TPB length. Furthermore, the TPB length had a strong correlation with the voltage deterioration rate.