Influence of green tea polyphenol in rats with arginine-induced renal failure

To determine whether green tea polyphenol ameliorates the pathological conditions induced by excessive dietary arginine, green tea polyphenol was administered to rats at a daily dose of 50 or 100 mg/kg body weight for 30 days with a 2% w/w arginine diet. In arginine-fed control rats, urinary and/or serum levels of guanidino compounds, nitric oxide (NO), urea, protein, and glucose increased significantly, while the renal activities of the oxygen species-scavenging enzymes superoxide dismutase (SOD) and catalase decreased, compared with casein-fed rats. However, rats given green tea polyphenol showed significant and dose-dependent decreases in serum levels of creatinine (Cr) and urea nitrogen and urinary excretion of Cr, and they exerted a slight reduction of nitrite plus nitrate, indicating that green tea polyphenol reduced the production of uremic toxins and NO. In addition, in arginine-fed rats the urinary urea, protein, and glucose level increases were reversed by the administration of green tea polyphenol. Moreover, in rats given green tea polyphenol the SOD and catalase activities suppressed by excessive arginine administration increased dose-dependently, implying the biological defense system was augmented as a result of free radical scavenging. These results suggest that green tea polyphenol would ameliorate renal failure induced by excessive dietary arginine by decreasing uremic toxin, and NO production and increasing radical-scavenging enzyme activity.     

Asynchronous climate changes in the North Atlantic and Japan during the last termination

Pollen records from the annually laminated sediment sequence in Lake Suigetsu, Japan, suggest a sequence of climate changes during the Last Termination that resembles that of the North Atlantic region but with noticeable differences in timing. An interstadial interval commenced a few centuries earlier [approximately 15,000 years before the present (yr B.P.)] than the North Atlantic GI-1 (B?lling) event. Conversely, the onset of a Younger Dryas (YD)-like cold reversal (12,300 to 11,250 yr B.P.) postdated the North Atlantic GS-1 (YD) event by a few centuries. Climate in the Far East during the Last Termination reflected solar insolation changes as much as Atlantic influences.     

The ecoresponsive genome of Daphnia pulex

We describe the draft genome of the microcrustacean Daphnia pulex, which is only 200 megabases and contains at least 30,907 genes. The high gene count is a consequence of an elevated rate of gene duplication resulting in tandem gene clusters. More than a third of Daphnia's genes have no detectable homologs in any other available proteome, and the most amplified gene families are specific to the Daphnia lineage. The coexpansion of gene families interacting within metabolic pathways suggests that the maintenance of duplicated genes is not random, and the analysis of gene expression under different environmental conditions reveals that numerous paralogs acquire divergent expression patterns soon after duplication. Daphnia-specific genes, including many additional loci within sequenced regions that are otherwise devoid of annotations, are the most responsive genes to ecological challenges.     

Detection and quantification of protein residues in food grade amino acids and nucleic acids using a dot-blot fluorescent staining method

Food allergies represent an important health problem in industrialized countries, such that detection and quantitative analysis of the protein considered to be the main allergen is crucial. A dot-blot fluorescent staining method for the detection and quantitative analysis of protein residues in food grade amino acids and nucleic acids is presented. This method combines fluorescence staining with dot-blotting onto PVDF membrane. Several standard proteins, such as bovine serum albumin (66 kDa), lysozyme (14 kDa), ubiquitin (8.6 kDa), bovine insulin (5.7 kDa), and oxidized insulin B chain (3.5 kDa), were detectable at 0.1 ppm using SYPRO Ruby blot stain. Twenty-five different amino acids and two different nucleic acids of food grade were analyzed using this method combined with an internal standard addition method using BSA as an internal standard. All amino acids and nucleic acids were dissolved in 3.6% aqueous HCl and dot-blotted onto PVDF membrane before a large amount of amino acids and nucleic acid were removed. Protein residues and the internal standard protein immobilized on the membrane were stained using SYPRO ruby blot stain. The internal standard in all samples was detectable at 0.1 ppm. Samples were dissolved at 120 or 70 mg/mL, according to their solubility under acidic conditions. The detection limit of protein residues per weight was 0.8-1.4 ppm in amino acids and nucleic acids; residual protein was not detected in any sample.     

Effect of 3-O-octanoyl-(+)-catechin on the responses of GABA(A) receptors and Na+/glucose cotransporters expressed in xenopus oocytes and on the oocyte membrane potential

Recently, 3-O-octanoyl-(+)-catechin (OC) was synthesized from (+)-catechin (C) by incorporation of an octanoyl chain into C in the light of (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), which are the major polyphenols found in green tea and have strong physiological activities. OC was found to inhibit the response of ionotropic gamma-aminobutyric acid (GABA) receptors (GABA(A) receptors) and Na+/glucose cotransporters expressed in Xenopus oocytes in a noncompetitive manner more strongly than does C. OC also induced a nonspecific membrane current and decreased the membrane potential of the oocyte, and thus death of the oocyte occurred even at lower concentrations than that induced by C or EGCg. Although EGCg produced H2O2 in aqueous solution, OC did not. This newly synthesized catechin derivative OC possibly binds to the lipid membrane more strongly than does C, Ecg, or EGCg and as a result perturbs the membrane structure.     

Pressure-induced denaturation of monomer beta-lactoglobulin is partially irreversible: comparison of monomer form (highly acidic pH) with dimer form (neutral pH)

This study was conducted to assess the effect of high hydrostatic pressure on monomer beta-lactoglobulin (BLg) at acid pH by fluorescence spectroscopy under pressure and by circular dichroism (CD) and (1)H NMR spectroscopies after release of pressure. The intrinsic (tryptophan) fluorescence measurement and the study of 8-anilinonaphthalene-1-sulfonate (ANS) binding to BLg indicated that at pH 2.0 the recovery of center of spectral mass or ANS fluorescence was almost complete upon pressure release. No difference in (1)H NMR spectra was observed between pressurized and unpressurized BLg. In addition, NMR detection of the H/D exchange of aromatic protein indicated that the conformation of the vicinity of tryptophan residues could be refolded almost completely after release of pressure. These results seemingly confirm that the pressure-induced denaturation of BLg at pH 2.0 is reversible. However, cis-parinaric acid binding ability of pressurized BLg was largely lost, although its retinol binding ability was the same as its unpressurized one. Furthermore, CD spectra of the far-UV region and 2D NMR spectra evidently revealed the difference in the conformation of the molecule between unpressurized and pressurized BLg. These results are interpreted as an existence of partially fragile structure in the BLg molecule by high pressure.     

Humoral immune response to non-viable Mycoplasma pulmonis in mice enhanced by dextran sulfate

The enhancing effect of dextran sulfate on the humoral immune response to nonviable Mycoplasma pulmonis in mice was evaluated by means of the indirect haemagglutination test. The serum antibody titres in mice immunized subcutaneously with a mixture of non-viable M. pulmonis and dextran sulfate were greater and persisted longer than those in mice immunized with non-viable M. pulmonis alone. DEAE-dextran also enhanced the humoral immune response to non-viable M. pulmonis in mice.     

Optimal pollination environment of tetraploid ginger (Zingiber officinale Roscoe) evaluated by in vitro pollen germination and pollen tube growth in styles

Pollen germination percentages in vitro of a tetraploid ginger (Zingiber officinale Roscoe), ‘4×Sanshu’, tended to be highest at around 20°C. Pollen tube growth in the styles was greatly enhanced at 17°C, i.e., pollen tubes penetrated into the entire stylar length in 66.7% of the styles used. Pollen stored for at least 3 h under 40–80% relative humidity (RH) almost completely lost its germinability, whereas pollen incubated for up to 3 h under 100% RH retained a relatively higher germinability. Moreover, the pollen germinability that was lowered under 40–80% RH did not recover when the pollen was re-humidified for 2 h under 100% RH before inoculation onto a medium. When stigmas were pollinated with fresh pollen at 17°C under 100% RH, pollen tubes penetrated into the entire stylar length in 26.7% of the styles tested. Under 40–80% RH, however, pollen tubes stopped growing at the middle or the base of styles. From these results, I concluded that the optimal pollination environment of the tetraploid ginger was at 17–20°C under 100% RH.