Fluoride ion adsorption isotherms, kinetics, and thermodynamics on iron(III) oxyhydroxide powders containing cellulose nanofibrils.

The adsorption isotherms, kinetics, and thermodynamics of fluoride ions (F-) on FeOOH powders in water were investigated to obtain fundamental information on FeOOH powders, which are used as F- adsorbents in drinking and industrial water, and industrial wastewater. FeOOH powders were prepared as precipitates by mixing aqueous FeCl3 and NaOH solutions (1:3 mol/mol) in the presence of 2,2,6,6,-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose nanofibrils (TOCNs), carboxymethylcellulose (CMC), or TEMPO-oxidized cellulose (TOC) fibers (without nanofibrillation), and subsequent drying and pulverizing. The FeOOH:TOCN, FeOOH:CMC, and FeOOH:TOC dry mass ratios were controlled at 87:13. The amount of F- adsorbed by the FeOOH/TOCN powder per FeOOH mass was higher than those adsorbed by FeOOH, FeOOH/CMC, or FeOOH/TOC. The F- adsorption isotherms on the FeOOH-containing powders showed higher correlation coefficients with the Langmuir model than with the Freundlich model. This indicates that F- adsorbed on FeOOH initially formed a monolayer, predominantly via physical adsorption. Pseudo-second-order kinetics fitted well to the time-dependent F- adsorption behaviors on the FeOOH-containing powders. Thermodynamic analysis of F- adsorption on the FeOOH-containing powders showed that the ΔG values were negative, which indicates that F- adsorption on the FeOOH-containing powders proceeded spontaneously in water. The negative ΔG value for FeOOH/TOCN was higher than those for FeOOH, FeOOH/CMC, and FeOOH/TOC at the same temperature. This shows that the FeOOH/TOCN powder can be used as an excellent and efficient F- adsorbent in water.

Structure-related cytotoxic activity of derivatives from kulokekahilide-2, a cyclodepsipeptide in Hawaiian marine mollusk.

Kulokekahilide-2, a 26-membered cyclodepsipeptide, was isolated from Hawaiian marine mollusk and possessed potent cytotoxicity in mammalian tumor cells. In the present study, we synthesized kulokekahilide-2 and its derivatives and examined the structure-activity relationships of these peptides in human cancer cells (A549, K562, and MCF7 cells). This study demonstrated that the cyclization of depsipeptide and the chirality of the 21 position in Ala in kulokekahilide-2 were important for its cytotoxic property and that addition of halogen at the para position of phenyl group in the 24-D-MePhe in kulokekahilide-2 as well as some derivatives remarkably increased their cytotoxicity in human cancer cells. These results suggest that the modifications of 24-D-MePhe in kulokekahilide-2, preserving its cyclization and the chirality at the 21-position, are promising strategy for exploring new derivative of kulokekahilide-2 as anti-tumor drug.

Genome sequence of the plant-pathogenic bacterium Dickeya dadantii 3937.

Dickeya dadantii is a plant-pathogenic enterobacterium responsible for the soft rot disease of many plants of economic importance. We present here the sequence of strain 3937, a strain widely used as a model system for research on the molecular biology and pathogenicity of this group of bacteria.

Suppressive effects of whey protein hydrolysate on sucrose-induced hyperglycemia in silkworms.

Silkworms are useful for evaluating substances that suppress postprandial hyperglycemia by oral administration. In this study, orally administered whey protein hydrolysate (WPH), obtained by enzymatic treatment of whey protein, suppressed sucrose-induced hyperglycemia in silkworms in a dose-dependent manner. WPH also inhibited glucose-induced hyperglycemia in silkworms. These findings suggest that WPH contains a bioactive peptide that inhibits glucose uptake from the intestinal tract and thereby suppresses sucrose-induced hyperglycemia.

Development of nobiletin-methyl hesperidin amorphous solid dispersion: Novel application of methyl hesperidin as an excipient for hot-melt extrusion.

A novel amorphous solid dispersion (ASD) of poorly water-soluble nobiletin (Nob) with highly water-soluble methyl hesperidin (MeHes) was developed. Mixtures of Nob and excipients (MeHes, cellulose derivatives, and synthetic polymers) were processed by hot-melt extrusion (HME). Powder X-ray diffraction analysis proved that most of the HME products were fully amorphized. In dissolution studies, Nob-MeHes ASD showed a prominently higher Nob concentration than other HME products with polymeric excipients. Nob concentration upon dissolution of Nob-MeHes ASD was 400 and 7.5 times higher than that upon dissolution of crystalline Nob and a Nob-MeHes physical mixture, respectively. In addition, Nob-MeHes ASD showed good preservation stability for 6 months under an accelerated condition of 40 °C and 80% relative humidity. Permeation studies using a Caco-2 cell monolayer showed that Nob-MeHes ASD markedly increased the amount of Nob transported. In mice, the plasma Nob concentration and accumulated amount of Nob in various tissues drastically increased after administration of Nob-MeHes ASD. This is the first successful application of MeHes, with a relatively low glass-transition temperature, as an excipient for an ASD formulation prepared by hot-melt extrusion. The drastic improvement in Nob concentration with a small-molecule excipient may be an important finding.

Effect of piceatannol-rich passion fruit seed extract on human glyoxalase I-mediated cancer cell growth.

Passion fruit seed extract (PFSE), a product rich in stilbenes such as piceatannol and scirpusin B, has various physiological effects. It is unclear whether PFSE and its stilbene derivatives inhibit cancer cell proliferation via human glyoxalase I (GLO I), the rate-limiting enzyme for detoxification of methylglyoxal. We examined the anticancer effects of PFSE in two types of human cancer cell lines with different GLO I expression levels, NCI-H522 cells (highly-expressed GLO I) and HCT116 cells (lowly-expressed GLO I). PFSE and its stilbenes inhibited GLO I activity. In addition, PFSE and its stilbenes supressed the cancer cell proliferation of NCI-H522 cells more than HCT116 cells. These observations suggest that PFSE can provide a novel anticancer strategy for prevention and treatment.

Investigation of epigallocatechin-3-O-caffeoate and epigallocatechin-3-O-p-coumaroate in tea leaves by LC/MS-MS analysis.

(-)-Epigallocatechin-3-O-gallate (EGCG), the major catechin present in green tea, exhibits potent antioxidant activity. We thereby investigated the presence of unknown components bearing the (-)-epigallocatechin (EGC) moiety in fresh tea leaf samples. Initially, liquid chromatography tandem mass spectrometry (LC-MS/MS) was employed to examine fresh tea leaves of the Yabukita, the most popular tea cultivar in Japan, which suggested the presence of the EGC phenylpropanoid derivatives, (-)-epigallocatechin-3-O-p-coumaroate (EGCpCA) and (-)-epigallocatechin-3-O-caffeoate (EGCCA). The structures of the detected EGCpCA and EGCCA were then confirmed by LC-MS/MS using synthesized EGCpCA and EGCCA as standards. In addition, EGCpCA and EGCCA were evaluated for their antioxidant activity in the ORAC (oxygen radical antioxidant capacity) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays, where EGCCA (8.60µmolTE/µmol, TE=Trolox equivalents) exhibited a stronger antioxidant activity than EGCG (5.52µmolTE/µmol) in the ORAC assay. Finally, EGCpCA and EGCCA were quantitated in several tea leaf samples using LC-MS/MS, and it was found that these compounds were present in lower quantities (EGCpCA, 16.8-345.8µg/g, EGCCA, 4.3-75.1µg/g in the dry tea leaves) than the major catechins. In this study, we found the potent antioxidant EGCCA using LC-MS/MS and revealed its wide existence in various tea leaves.

Peh production, flagellum synthesis, and virulence reduced in Erwinia carotovora subsp. carotovora by mutation in a homologue of cytR.

Erwinia carotovora subsp. carotovora is a causal agent of soft-rot diseases in a wide variety of plants. Here, we have isolated a new regulatory factor involved in the virulence of E. carotovora subsp. carotovora by in vivo insertional mutagenesis using a transposon Tn5. The gene was homologous to cytR encoding a transcriptional repressor of nucleoside uptake and catabolism genes in Escherichia coli, Salmonella typhimurium, and Vibrio cholerae. Phenotypic characterization of a nonpolar deletion mutant of the cytR homologue (delta cytR) revealed that the delta cytR mutant produced a reduced level of polygalacturonase (Peh) and lost its motility compared to that in the parental strain. With electron microscopy, the delta cytR mutant was shown to be aflagellate. Furthermore, the expression of fliA and fliC (encoding sigma28 and flagellin, respectively) was also reduced in delta cytR mutant. The virulence of delta cytR mutant was reduced in Chinese cabbage and potato compared to that of the parental strain. These results suggest that the CytR homologue of E. carotovora subsp. carotovora positively controls Peh production and flagellum synthesis and plays an important role in its pathogenicity.