Regulatory Role of Sugars on the Settlement Inducing Activity of a Conspecific Cue in Pacific Oyster Crassostrea gigas

This study evaluated the larval settlement inducing effect of sugars and a conspecific cue from adult shell extract of Crassostrea gigas. To understand how the presence of different chemical cues regulate settlement behavior, oyster larvae were exposed to 12 types of sugars, shell extract-coated and non-coated surfaces, and under varied sugar exposure times. Lectin-glycan interaction effects on settlement and its localization on oyster larval tissues were investigated. The results showed that the conspecific cue elicited a positive concentration dependent settlement inducing trend. Sugars in the absence of a conspecific cue, C. gigas adult shell extract, did not promote settlement. Whereas, in the presence of the cue, showed varied effects, most of which were found inhibitory at different concentrations. Sugar treated larvae exposed for 2 h showed significant settlement inhibition in the presence of a conspecific cue. Neu5Ac, as well as GlcNAc sugars, showed a similar interaction trend with wheat germ agglutinin (WGA) lectin. WGA-FITC conjugate showed positive binding on the foot, velum, and mantle when exposed to GlcNAc sugars. This study suggests that a WGA lectin-like receptor and its endogenous ligand are both found in the larval chemoreceptors and the shell Ethylenediaminetetraacetic acid (EDTA) extract that may complementarily work together to allow the oyster larva greater selectivity during site selection.     

Dietary lysophospholipids reduce lymphatic cholesterol transport compared with dietary phospholipids in thoracic lymph-duct cannulated rats

Dietary phospholipids have been traditionally known to affect micelle formation. Egg yolk-derived lysophospholipids (LysoPL) are commercially available. We investigated the effects of dietary LysoPL on lymphatic lipid transport. We also compared sn-1 LysoPL and sn-2 LysoPL, which have different fatty acyl esterification positions. Thoracic lymph duct-cannulated rats were fed a diet supplemented with egg yolk-derived sn-1 LysoPL, sn-2 LysoPL, or phospholipids (PL). The amount of lymphatic lipid transport was also evaluated. Time courses of transport were applied to the one-compartment model as one of the pharmacokinetic analyses. The solubility of cholesterol in bile acid micelles was measured. Compared to the PL diet, the sn-1 and sn-2 LysoPL diets significantly reduced the lymphatic transport of cholesterol. There were no differences in the lymphatic PL and TAG transport. There was no difference in cholesterol transport between the sn-1 LysoPL group and the sn-2 LysoPL group; however, the transport rate constant at a decrease in lymphatic cholesterol was lower in the sn-1 LysoPL group than in the sn-2 LysoPL group. Cholesterol solubility in bile acid micelles was significantly decreased in the sn-1 LysoPL and sn-2 LysoPL groups compared to that in the PL group. Dietary LysoPL affects the behavior of intestinal cholesterol and suppresses lymphatic cholesterol transport.     

Characterization of a Large-Scale Nondoped YBa2Cu3O7−x Superconductor Prepared by Plastic Forming Without High-Pressure Molding

A slurry containing YBa₂Cu₃O_{7− x} particles and a fine YBa₂Cu₃(OH) _x colloid solution was prepared, and a large-scale bulk YBa₂Cu₃O_{7− x} superconductor (about 50 mm × 35 mm × 2 mm) was produced by plastic forming without high-pressure molding. The samples molded from the slurry were dried and then fired at 1223 K in air. X-ray diffraction data indicated that the samples had the characteristic orthorhombic YBa₂Cu₃O_{7− x} structure. Measurements of electrical resistance were carried out between 300 and 50 K by the standard four-probe DC electrical measurement. The samples began superconducting at an onset temperature around 92 K, and the full-transition temperature (critical temperature) ( T _c) was 88.7±1.4 K. The critical current density ( J _c) measured at 77 K was about 440 A/cm², the value of J _c was improved by the heat treatment under an oxygen atmosphere, and J _c=1.6 × 10³ A/cm² was observed. Under the magnetic field (B=1 T), the sample held its superconductivity, and demonstrated that this method can be used to produce the magnetic shielding used in magnetic resonance imaging diagnosis.     

Soy-Derived Equol Induces Antioxidant Activity in Zebrafish in an Nrf2-Independent Manner

Antioxidant effects of soy-derived isoflavones are predicted to be mediated by the Keap1-Nrf2 pathway. Recently, we constructed an assay system to evaluate the antioxidant effects of dietary phytochemicals in zebrafish and revealed a relationship between these effects and the Keap1-Nrf2 pathway. In this study, we used this system to examine the antioxidant effects of seven isoflavones. Among those seven, equol showed strong antioxidant effects when arsenite was used as an oxidative stressor. The antioxidant effect of equol was also shown in Nrf2-mutant zebrafish nfe2l2a^fh318, suggesting that this effect was not mediated by the Keap1-Nrf2 pathway. To elucidate this unidentified mechanism, the gene expression profiles of equol-treated larvae were analyzed using RNA-seq and qRT-PCR, while no noticeable changes were detected in the expression of genes related to antioxidant effects, except weak induction of Nrf2 target genes. Because nfe2l2a^fh318 is an amino acid-substitution mutant (Arg485Lue), we considered that the antioxidant effect of equol in this mutant might be due to residual Nrf2 activity. To examine this possibility, we generated an Nrf2-knockout zebrafish nfe2l2a^it321 using CRISPR-Cas9 and analyzed the antioxidant effect of equol. As a result, equol showed strong antioxidant effects even in Nrf2-knockout larvae, suggesting that equol indeed upregulates antioxidant activity in zebrafish in an Nrf2-independent manner.     

Isolation of Endotoxin Eliminating Lactic Acid Bacteria and a Property of Endotoxin Eliminating Protein

Recently, many scholars have reported lactic acid bacteria (LAB) functions, such as anticancer activity and anti‐inflammatory activity for intestines. To decrease inflammatory substances such as endotoxins, LAB consumed safely with meals were isolated from food and food ingredients. First, LAB were isolated as 168 strains of bacillus LAB (49 strain) and coccus LAB (119 strains) from food ingredients and fermented foods such as rice, rice bran, malt, grains, miso soy paste, and some pickles. Their LAB (168 strains) were cultivated in medium containing endotoxin from Escherichia coli O18 LPS at 15 and 30 °C for 64 h to identify endotoxin‐eliminating LAB. Consequently, the AK‐23 strain was screened as an endotoxin‐eliminating LAB strain. The strain decreased endotoxin in YP medium without sugar at 30 °C for 64 h until 9% of endotoxin. The strain was identified as Pediococcus pentosaceus according to morphological characteristics such as its cell shape, physiological characteristics related to its fermentation type, assimilation of sugars, pH tolerance, optimum growth temperature, and molecular biological characteristics as its homology to 16S rRNA. To investigate the location of the endotoxin‐eliminating substance, 4 fractions were separated from AK‐23 cells as extracellular, cell wall digestion, cytoplasm, and cell membrane fractions. The endotoxin‐decreasing substance, located on a cell wall, was identified as a 217 kDa protein.     

Fluid flow and heat transfer of natural convection adjacent to upward‐facing inclined heated plates

Turbulent transition mechanism and local heat transfer characteristics of the natural convective flows over upward‐facing inclined plates were investigated experimentally. The experiments were performed in the range of modified local Rayleigh numbers from 10⁴ to 8 × 10¹⁴ and of inclination angles θ from 0 to 90°. The flow fields over the plate and the surface temperatures of the plate were visualized with dye and liquid crystal thermometry. The results showed that longitudinal vortices play a main role in the turbulent transition over the plate of θ < 72°. These vortices appear first in the laminar boundary layer, then detach from the plate and, finally become distorted. It is found that the heat transfer is enhanced markedly by the detachment and the distortion of these vortices. The local heat transfer coefficients were measured in the laminar, transitional, and turbulent regions. The results show that the coefficients in the turbulent region become identical and independent of inclination angles. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 278–291, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10091     

Fluid flow and heat transfer of natural convection at a slightly inclined,upward‐facing,heated plate

Natural convective flows over upward‐facing, inclined plates were investigated experimentally, with an emphasis on the role of opposing flows that appear over the plates inclined slightly from the horizontal line. The flow fields over the plates and the surface temperatures of the heated plates were visualized with both dye and a liquid‐crystal thermometry. The results showed that both the descending and ascending flows appeared over the plates when the inclination angles of the plates were less than 15°. The two flows collided with each other at a certain distance from the plate edge, and then detached from the plate to become a thermal plume. It was found that the above distance was determined solely by the inclination angles and was independent of sizes and heat fluxes of the plates. The local heat transfer coefficients of the plates were also measured. The results showed that the heat transfer from the plate was enhanced by the occurrence of the descending flows. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(5): 362–375, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10036     

An ESCA study of the Fe2+/Fe3+ ratio in passive films on iron-chromium alloys

X-ray photoelectron spectra of Fe $\text{2p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ electrons are measured for passive films on iron and FeCr alloys passivated for 1 h in 1M H₂SO₄ at + 100 and + 500 mV (s.c.e.). When chromium content of FeCr alloys increased to ca. 12 at.%, binding energy of Fe $\text{2p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ electrons from oxidized state shifted abruptly from ca. 710·3 to ca. 709·6 eV and no more change in binding energy was observed at high chromium content. This abrupt shift of binding energy is in accord with the fact that the Fe²⁺/Fe³⁺ ratio showed sharp increase at ca. 12 at.% chromium. This phenomenon can be attributed to the inhibition of oxidation of iron due to the change in film structure and properties.     

SPR imaging of photo-cross-linked small-molecule arrays on gold

Identification of small-molecule ligands for a protein of interest can facilitate the analysis of the protein's functions in biological systems. Small-molecule microarrays have allowed for rapid detection of such ligand-protein interactions in a high-throughput manner, although a label on a protein is needed to observe these interactions. By combining SPR imaging technology with our recently developed photo-cross-linked small-molecule array platform, we developed a novel platform that allows in situ observation of interactions between photo-cross-linked small molecules on gold surfaces and nonlabeled proteins in solution. Interactions of estrogenic and androgenic substances with estrogen receptor alpha were observed using this platform.