Bis(5‐hydroxy‐2‐hydroxy­methyl‐4‐pyrone‐κ2O4,O5)bis(2‐hydroxy­methyl‐5‐oxido‐4‐pyrone‐κ2O4,O5)­calcium(II) tetrahydrate

In the title compound, [Ca(C₆H₅O₄)₂(C₆H₆O₄)₂]·4H₂O, which is a kojic acid–Ca²⁺ complex, the Ca atom is on a twofold axis and is octacoordinated by O atoms from four pyrone ligand mol­ecules. The hydroxyl and ketone O atoms of each ligand form a five‐membered chelate ring with the Ca atom. The crystal structure is stabilized by partial stacking and O—H?O hydrogen bonds.     

Hypotensive effects on spontaneously hypertensive rats and antifungal activity on various species of Fusarium oxysporum of diethylstilbestrol-related compounds

The diethylstilbestrol-related compounds 3,3'-dihydroxy-alpha, beta-diethyldiphenylethane (I), diethylstilbestrol (II) and hexestrol (III) showed hypotensive effects on spontaneously hypertensive rats (SHR) and antifungal activities against all Fusarium oxysporum sp. tested. As previously reported, I had strong hypotensive action on normotensive rats at the dose of 10 mg/kg, while II and III showed weak hypotensive effects on these rats at the same dose. In this work, all three compounds also had hypotensive actions on SHR at the same dose. I showed the strongest hypotensive effect (-80.0 +/- 5.0 mmHg, 10 mg/kg, i.v.) on both SHR and normotensive rats. The three compounds also had antifungal activities against five kinds of Fusarium oxysporum sp. tested. Especially, II strongly inhibited the growth of Fusarium oxysporum f. sp. raphani IFO-9972 (minimum inhibitory concentration (MIC): 1.0 micrograms/ml).     

Inhibitory effects of 3,3',4,5'-tetrahydroxystilbene and 3,3',4,5'-tetrahydroxybibenzyl, the constituents of Cassia garrettiana on antigen-induced histamine release in vitro.

3,3',4,5'-Tetrahydroxystilbene (I) and 3,3',4,5'-tetrahydroxybibenzyl (II), isolated from the heartwood of Cassia garrettiana Craib (Leguminosae), showed inhibitory effects on antigen-induced histamine release from rat peritoneal mast cells in vitro. The inhibitory effect of I (IC50 = 30.2 microM) was much stronger than that of II (greater than 100 microM). Compound II, as well as I (IC50 = 7.3 microM) reported previously, also inhibited the histamine release from human peripheral basophils induced by anti-immunoglobulin E (IgE) in vitro, and its IC50-value was 68.0 microM. These results suggest that the trans-olefin structure in the molecule may be necessary for I to have an inhibitory effect on histamine release. Considering that disodium cromoglycate did not show any significant inhibitory effect on anti-IgE-induced histamine release from human basophils, the strong inhibitory effects of I in both tests are of considerable interest.     

Application of plug–plug technique to ACE experiments for discovery of peptides binding to a larger target protein: A model study of calmodulin‐binding fragments selected from a digested mixture of reduced BSA

To discover peptide ligands that bind to a target protein with a higher molecular mass, a concise screening methodology has been established, by applying a “plug–plug” technique to ACE experiments. Exploratory experiments using three mixed peptides, mastoparan‐X, β‐endorphin, and oxytocin, as candidates for calmodulin‐binding ligands, revealed that the technique not only reduces the consumption of the protein sample, but also increases the flexibility of the experimental conditions, by allowing the use of MS detection in the ACE experiments. With the plug–plug technique, the ACE–MS screening methodology successfully selected calmodulin‐binding peptides from a random library with diverse constituents, such as protease digests of BSA. Three peptides with K_d values between 8–147 μM for calmodulin were obtained from a Glu‐C endoprotease digest of reduced BSA, although the digest showed more than 70 peaks in its ACE–MS electropherogram. The method established here will be quite useful for the screening of peptide ligands, which have only low affinities due to their flexible chain structures but could potentially provide primary information for designing inhibitors against the target protein.     

Enhancement of Solar Hydrogen Evolution from Water by Surface Modification with CdS and TiO2 on Porous CuInS2 Photocathodes Prepared by an Electrodeposition–Sulfurization Method

Porous films of p‐type CuInS₂, prepared by sulfurization of electrodeposited metals, are surface‐modified with thin layers of CdS and TiO₂. This specific porous electrode evolved H₂ from photoelectrochemical water reduction under simulated sunlight. Modification with thin n‐type CdS and TiO₂ layers significantly increased the cathodic photocurrent and onset potential through the formation of a p–n junction on the surface. The modified photocathodes showed a relatively high efficiency and stable H₂ production under the present reaction conditions.     

Removal of phosphate by aluminum oxide hydroxide

The development and manufacture of an adsorbent to remove phosphate ion for the prevention of eutrophication in lakes are very important. The characteristics of phosphate adsorption onto aluminum oxide hydroxide were investigated to estimate the adsorption isotherms, the rate of adsorption, and the selectivity of adsorption. Phosphate was easily adsorbed onto aluminum oxide hydroxide, because of the hydroxyl groups. The adsorption of phosphate onto aluminum oxide hydroxide was influenced by pH in solution: the amount adsorbed was greatest at pH 4, ranging with pH from 2 to 9. The optimum pH for phosphate removal by aluminum oxide hydroxide is 4. The selectivity of phosphate adsorption onto aluminum oxide hydroxide was evaluated based on the amount of phosphate ion adsorbed onto aluminum oxide hydroxide from several anion complex solutions. It is phosphate that aluminum oxide hydroxide can selectively adsorb. The selectivity of phosphate onto aluminum oxide hydroxide was about 7000 times that of chloride. This result indicated that the hydroxyl groups on aluminum oxide hydroxide have selective adsorptivity for phosphate and could be used for the removal of phosphate from seawater.