Analytical approach to the discoloration of edible laver "nori" in the Ariake Sea.

To understand the cause of discoloration of the sea laver "nori," which is found in the Ariake Sea, the concentrations of pigments and elements in the normal and discolored laver samples were determined. In the discolored samples, a decrease in all of the pigments, chlorophyll a and carotenoids, and proteinous pigments, phycobiliproteins, was clearly observed. This was accompanied by a decrease in the content of Fe, Zn, Mn, Cu, and P. Good correlations between these elements and chlorophyll a, as well as between these elements and phycobiliproteins, were confirmed, indicating that, in addition to the deficiency of nitrogen and phosphorus, the deficiency of trace elements (Fe, Zn, Mn, and Cu), which are specifically required for photosynthesis, could be a reason for the discoloration of nori. The cause of elemental deficiency is also discussed.     

Novel carbohydrate-appended metal complexes for potential use in molecular imaging

Seven discrete sugar-pendant diamines were complexed to the {M(CO)(3)}(+) ((99m)Tc/Re) core: 1,3-diamino-2-propyl beta-D-glucopyranoside (L(1)), 1,3-diamino-2-propyl beta-D-xylopyranoside (L(2)), 1,3-diamino-2-propyl alpha-D-mannopyranoside (L(3)), 1,3-diamino-2-propyl alpha-D-galactopyranoside (L(4)), 1,3-diamino-2-propyl beta-D-galactopyranoside (L(5)), 1,3-diamino-2-propyl beta-(alpha-D-glucopyranosyl-(1,4)-D-glucopyranoside) (L(6)), and bis(aminomethyl)bis[(beta-D-glucopyranosyloxy)methyl]methane (L(7)). The Re complexes [Re(L(1)-L(7))(Br)(CO)(3)] were characterized by (1)H and (13)C 1D/2D NMR spectroscopy which confirmed the pendant nature of the carbohydrate moieties in solution. Additional characterization was provided by IR spectroscopy, elemental analysis, and mass spectrometry. Two analogues, [Re(L(2))(CO)(3)Br] and [Re(L(3))(CO)(3)Br], were characterized in the solid state by X-ray crystallography and represent the first reported structures of Re organometallic carbohydrate compounds. Conductivity measurements in H(2)O established that the complexes exist as [Re(L(1)-L(7))(H(2)O)(CO)(3)]Br in aqueous conditions. Radiolabelling of L(1)-L(7) with [(99m)Tc(H(2)O)(3)(CO)(3)](+) afforded in high yield compounds of identical character to the Re analogues. The radiolabelled compounds were determined to exhibit high in vitro stability towards ligand exchange in the presence of an excess of either cysteine or histidine over a 24 h period.     

Laser-induced orientational change of nematic liquid crystalline molecules mediated by photochromic reactions of surface azobenzenes

The alignment of nematic liquid crystalline (LC) molecules with respect to the LC cell surface was regulated between the homeotropic (H) state and the parallel (P) state by the photochromic trans—cis isomerization of surface-attached azobenzene (Az) moieties. By bringing the angular-selective photoreaction into the system, the orientational order in the P state was significantly improved to attain a universal orientational axis over the entire irradiated area, which was rotatable and erasable photochemically. Laser pulse experiments revealed that the allignment relaxation time τ was reduced from 1000 to 30 ms by increasing the pulse intensity from 10 to 20 mJ cm⁻². Strong coupling between the LC and Az molecules was indicated.     

Analysis of lipid surface area in protein-membrane systems combining Voronoi tessellation and Monte Carlo integration methods

All-atom molecular dynamics (MD) simulation has become a powerful research tool to investigate structural and dynamical properties of biological membranes and membrane proteins. The lipid structures of simple membrane systems in recent MD simulations are in good agreement with those obtained by experiments. However, for protein-membrane systems, the complexity of protein-lipid interactions makes investigation of lipid structure difficult. Although the area per lipid is one of the essential structural properties in membrane systems, the area in protein-membrane systems cannot be computed easily by conventional approaches like the Voronoi tessellation method. To overcome this limitation, we propose a new method combining the two-dimensional Voronoi tessellation and Monte Carlo integration methods. This approach computes individual surface areas of lipid molecules not only in bulk lipids but also in proximity to membrane proteins. We apply the method to all-atom MD trajectories of the sarcoplasmic reticulum Ca(2+)-pump and the SecY protein-conducting channel. The calculated lipid surface area is in agreement with experimental values and consistent with other structural parameters of lipid bilayers. We also observe changes in the average area per lipid induced by the conformational transition of the SecY channel. Our method is particularly useful for examining equilibration of lipids around membrane proteins and for analyzing the time course of protein-lipid interactions.     

Interactions between temperature-sensitive hydrogel microspheres and granulocytes

Poly(N-isopropylacrylamide) (PNIPAM) has a low critical solution temperature (LCST) at 32°C in water and the hydrophilicity changes through the LCST. The microspheres whose surface was composed of PNIPAM exhibited phase transition behavior around 32°C. Therefore, the interactions between PNIPAM micropheres and granulocytes depended on the temperature. That is, the oxygen consumption and active oxygen production by cells in contact with PNIPAM-containing microspheres and adhesion of the microspheres to the cell surface were more enhanced above the LCST of PNIPAM than below it, whereas no significant temperature dependence of cell–microspheres interaction was observed in nonthermosensitive microsphere systems. It was suggested that the function of cells could be controlled with temperature using the temperature-sensitive microspheres.     

Effects of sulfate ligand on uranyl carbonato surface species on ferrihydrite surfaces

Understanding uranium (U) sorption processes in permeable reactive barriers (PRB) are critical in modeling reactive transport for evaluating PRB performance at the Fry Canyon demonstration site in Utah, USA. To gain insight into the U sequestration mechanism in the amorphous ferric oxyhydroxide (AFO)-coated gravel PRB, U(VI) sorption processes on ferrihydrite surfaces were studied in 0.01 M Na(2)SO(4) solutions to simulate the major chemical composition of U-contaminated groundwater (i.e., [SO(4)(2-)] ~13 mM L(-1)) at the site. Uranyl sorption was greater at pH 7.5 than that at pH 4 in both air- and 2% pCO(2)-equilibrated systems. While there were negligible effects of sulfate ligands on the pH-dependent U(VI) sorption (<24 h) in both systems, X-ray absorption spectroscopy (XAS) analysis showed sulfate ligand associated U(VI) surface species at the ferrihydrite-water interface. In air-equilibrated systems, binary and mono-sulfate U(VI) ternary surface species co-existed at pH 5.43. At pH 6.55-7.83, a mixture of mono-sulfate and bis-carbonato U(VI) ternary surface species became more important. At 2% pCO(2), there was no contribution of sulfate ligands on the U(VI) ternary surface species. Instead, a mixture of bis-carbonato inner-sphere (38%) and tris-carbonato outer-sphere U(VI) ternary surface species (62%) was found at pH 7.62. The study suggests that the competitive ligand (bicarbonate and sulfate) coordination on U(VI) surface species might be important in evaluating the U solid-state speciation in the AFO PRB at the study site where pCO(2) fluctuates between 1 and 2 pCO(2)%.     

Synthesis, characterization, and reactivity of a novel μ-η2:η2-diselenidodicopper(II) complex

The first μ-η(2):η(2)-diselenidodicopper(II) complex has been obtained in the reaction of a copper(I) complex with N,N',N″-tribenzyl-cis,cis-1,3,5-triaminocyclohexane and elemental selenium. The structure and reactivity of the complex is described.     

Blockade of inflammatory responses by a small-molecule inhibitor of the Rac activator DOCK2

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Highlights? CPYPP binds to DOCK2 DHR-2 domain and inhibits its catalytic activity ? CPYPP inhibits DOCK2-mediated Rac activation in cells ? The structural features of CPYPP required for its inhibitory effect were revealed ? CPYPP inhibits lymphocyte migration and activation in vitro and in vivo     

A New Family of Indoaniline-Derived Calix[4]arenes: Synthesis and Optical Recognition Properties as a Chromogenic Receptor(1)

A new family of indoaniline-derived calix[4]arenes has been synthesized for the purpose of developing a new chromogenic receptor. A condensing reaction of calix[4]arene (1) with 4-(diethylamino)-2-methylaniline hydrochloride (2) in the presence of an oxidizing agent under alkaline conditions affords mono- (3), 1,2-bis- (4), 1,3-bis- (5), and tetrakisindoaniline-derived (6) calix[4]arenes after careful column chromatography. Compound 3 is crystallized from a CHCl(3)-MeOH solution, and the crystal structure was determined by X-ray analysis. The crystal is monoclinic, space group P2(1)/n, Z = 4, a = 19.507(6) ?, b = 18.591(6) ?, c = 8.524(2) ?, beta = 94.69(2) degrees. The final R value for 2406 reflections of F(o) > 3sigma(F(o)) is 0.085. A unique intramolecular hydrogen-bonding network involving the carbonyl oxygen of indoaniline for 3 implied that the quinone carbonyl group as an acceptor of the chromophore can easily be subjected to an electrostatic interaction in the lower rim. Indeed, 1,3-bis(indoaniline)-derived 2,4-bis((ethoxycarbonyl)methoxy)calix[4]arene 7, prepared by the reaction of 5 with ethyl bromoacetate in the presence of NaH, is capable of undergoing an efficient ion-dipole interaction between the binding cation and the two quinone carbonyl groups of the chromophores, so that a selective Ca(2+)-induced pronounced color change (wavelength change > 100 nm) occurs with an association constant on the order of 10(6) in 99% EtOH, making 7 of potential use as an optical sensor for Ca(2+) detection. The IR and NMR studies have indicated that Ca(2+) is encapsulated in the cavity made by the distally located OCH(2)CO(2) groups on the lower rim of the cone-shaped calix[4]arene segment. Interestingly, however, the shape of the cavity in which Ca(2+) has been encapsulated does not have a C(2) axis of symmetry, as inferred from the (1)H-(1)H COSY experiment. On the other hand, 1,2-bis(indoaniline)-derived analogue 8 shows no response with metal ions, which can be interpreted to mean the absence of a cavity for encapsulation on the lower rim.