Development of monoclonal-based enzyme-linked immunosorbent assay and immunochromatographic assay for lasalocid and semduramicin

Monoclonal antibodies (MAbs) against lasalocid and semduramicin were prepared using keyhole limpet hemocyanin conjugates for the immunization of mice. With these MAbs, we developed quantitative enzyme-linked immunosorbent assay (ELISA) methods for lasalocid and semduramicin. The ELISAs were quantitative in the ranges of 0.1-50 ng/mL for lasalocid and 0.05-12.5 ng/mL for semduramicin, and showed 50% inhibition concentrations of 1.2 ng/mL for lasalocid and 0.5 ng/mL for semduramicin. The coefficient of variations (CV%) of lasalocid were 0.3-4.4% for intra-assay and 0.5-5.1% for inter-assay and those of semduramicin were 0.1-4.6% for intra-assay and 0.3-5.2% for inter-assay. The detection limits for lasalocid and semduramicin were 10 ng/g and 5 ng/g in chicken liver and muscle, respectively. Based on the immunochromatographic method, rapid test kits for lasalocid and semduramicin were also developed. With these kits, the detection limits of lasalocid were 50 ng/mL for standard solution and 125 ng/g for chicken muscle, and those of semduramicin were 10 ng/mL for standard solution and 100 ng/g for chicken muscle.     

Binary Adsorption Isotherms of Water and Ethyl Acetate Vapor for Materials Contained in a Box of a Tobacco Product

ABSTRACT

An experimental study has been carried out on the characteristics of binary adsorption isotherms of water and volatile flavor for typical materials used in a box of a tobacco product or cigarettes. Ethyl acetate chosen as a model for water–soluble volatile flavor. Binary adsorption isotherms for the tobacco, papers, filters, and activated carbons were measured with a flow–type multi–component adsorption system under the canstant conditions of temperature a t 303 K and vapor pressure of water a t 2.5 kPain the vapor pressure range of ethyl acetate from 0 to 4.2 kPa. A linear equation was applied to express the binary adsorption isotherms for the tobacco, papers and filters, while a Dubinin–Astakhov equation was applied for the activated carbons. The binary adsorption was characterized into three groups, depending on the selectivity as well as the mechanism of adsorption; i.e.(l) for tobacco and papers, water was adsorbed much greater rather than ethyl acetate, (2) for filters, ethyl acetate was adsorbed on the surface as great as water, (3) for activated carbons, ethyl acetate was adsorbed much greater onto their micropores rather than water. The results showed that ethyl     

Efficient photocatalytic activity of water oxidation over WO3/BiVO4 composite under visible light irradiation

A coupled WO₃/BiVO₄ thin film has been deposited on FTO substrate by a spin coating method from precursor solutions. The composite films were characterized by AFM, SEM, XPS and XRD techniques. The incident photon to current efficiency (IPCE) of BiVO₄ electrode was increased by 10 times when a WO₃ film was layered between the BiVO₄ layer and the FTO substrate. The enhanced performance of WO₃/BiVO₄ composite film electrode is mainly ascribed to the effective electron-hole separations at the semiconductor heterojunction. A schematic mechanism of charge transfer was proposed to explain the photocurrent enhancement for the WO₃/BiVO₄ electrode surface.     

Determination of spatial grain size with the area-weighted grain area distribution of the planar sections in polycrystalline materials

The electron backscattering diffraction (EBSD) technique has made it quite easy to obtain the grain area distribution in a planar section of the polycrystalline materials. Usually, area-weighted grain area and number-weighted grain area show completely different distribution profiles. Instead of the nominal average grain size calculated from the grain area distribution results, the spatial grain size and its distribution character reflect the real features of the materials and those parameters are expected through a simple measurement on the planar sections. In the present work, the section area distribution model of a randomly sliced truncated octahedron is used to relate the lognormally distributed spatial grain size to the area-weighted grain size distribution features. Based on the truncated octahedron grain shape model, area-weighted grain area distribution is derived by convoluting the lognormal distribution of the area of the section with the maximum section area (SMSA) in each grain and the area-weighted section area distribution of the sliced truncated octahedron. It is found that area-weighted grain area distribution on a planar section shows also the lognormal distribution character when the spatial grain size has the lognormal distribution character. Meanwhile, the variance parameter, τ(ins), and the mean value of grain area, , obtained by fitting the area-weighted grain area distribution, have also been related to the lognormal distribution characters of the spatial grain size, i.e., A and . The simulation results are then experimentally checked on a polygonal grain structure of hot-rolled low-carbon steel by applying the point-sampling method to obtain the spatial grain size distribution features.     

Survey of synthetic disinfectants in grapefruit seed extract and its compounded products

Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.     

Epicoprostanol found in adipocere from five human autopsies

Adipocere formation is well known as a later postmortem change. We collected adipocere from five male victims which had been submerged under the sea or fresh water for 1 mon to 4 yr. Fresh subcutaneous fat of a male victim who died from a cerebral contusion was used as the control. The samples were homogenized, and the lipids were extracted with chloroform and methanol followed by injection into a gas chromatograph and a gas chromatograph-mass spectrometer. We detected hydroxy fatty acids (10-hydroxyocatadecanoic and 10-hydroxyhexadecanoic acid) as well as 10-ketooctadecanoic acid in adipocere, but not in the control. In addition, we found for the first time a cholesterol-related peak with a molecular ion of 388 in adipocere and identified it as epicoprostanol, suggesting not only oxidation but also reduction had occurred during the formation of adipocere. In addition, we showed the time-course of epicoprostanol accumulation. The relationship between the time of adipocere formation and the characteristic lipid composition is discussed.     

Single-molecule imaging of the dynamic interactions between macromolecules

In recent years, the development of single-molecule detection techniques has allowed the dynamic properties of biomolecules, which are normally obscured in conventional ensemble measurements, to be measured. One of these single-molecule detection techniques allows the measurement of dissociation and association events of individual molecules to be measured. This technique is based on the unique premise that the mobility between molecules that are bound and the mobility between those that are free in solution are different. The binding of ATP at the beginning and its dissociation at the end of the hydrolysis reaction were detected at the single-molecule level in real time. In this study, we extended this technique to image the dynamic interactions between large biomolecules (protein/protein and protein/polysaccharide). The binding and dissociation of fluorescently labeled macromolecules to partner molecules fixed on a glass surface were visualized by total internal reflection fluorescence microscopy. The dynamic interactions between the proteins in two energy conversion systems, that is, signaling proteins and enzyme molecules moving on dextran, have been measured. In these systems, the dynamic interactions were sensitive to the factors determining the chemical reactions. Thus, the dynamic interactions monitored in the single-molecule measurements provided useful information to further the understanding of the underlying mechanisms of energy conversion systems.     

Effects of the fermentation product of herbs by lactic acid bacteria against phytopathogenic filamentous fungi and on the growth of host plants

The fermentation product of herbs by lactic acid bacteria (FHL) was assayed for antifungal activities against Rosellinia necatrix, Helicobasidium mompa, Fusarium oxysporum, Pythium graminicola and Pyricularia oryzae. FHL completely inhibited the growth of R. necatrix, H. mompa, P. graminicola and P. oryzae, and reduced the growth of F. oxysporum by 35%. When the seeds of Medicago sativa L. (alfalfa), Asparagus officinalis L. (asparagus), Brassica campestris L. (komatsuna), Oryza sativa L. (rice), Spinacia oleracea L. (spinach), Festuca arundinacea Schreb. (tall fescue), and Lycopersicum esculentum Mill. (tomato) were put on plates containing 0.69 mg/ml FHL, their germination rates did not decrease. The root elongation of A. officinalis, B. campestris, O. sativa, and L. esculentum seedlings was suppressed on plates containing 6.92 mg/ml FHL, but the root elongation of M. sativa was not suppressed on the 6.92 mg/ml FHL plate. When FHL was diluted to less than 1.73 mg/ml, the diluted FHL solution did not suppress the germination of B. campestris seeds, but it suppressed the root elongation of B. campestris seedlings. An FHL concentration higher than 0.35 mg/ml hastened the growth of seedlings of B. campestris in the presence of a chemical fertilizer but delayed the growth of these seedlings in the absence of the chemical fertilizer, suggesting that inorganic elements could affect the efficiency of FHL.     

Application of graft-type poly(ether ether ketone)-based polymer electrolyte membranes to electrochemical devices – Fuel cells and electrolytic enrichment of tritium

The polymer electrolyte membrane consisting of poly(styrenesulfonic acid)-grafted poly(ether ether ketone) (PEEK-PEM) was investigated for application to two electrochemical devices; a fuel cell and electrolytic enrichment of tritium. For fuel cells, high temperature operation has been required from the viewpoints of simplification of cooling systems, heat recovery systems and so forth, and durability is one critical issue affecting practical use. We performed a long term durability test for PEEK-PEM (ion exchange capacity = 2.4 mmol/g, conductivity = 0.15 S/cm) under the condition of 110 °C and 50% relative humidity, and achieved a lifetime of 1500 h at a constant current of 0.3 A/cm². The cell voltage maintained 97% of initial voltage after 1300 h of operation. There have been only a few reports that PEMs exhibit longer lifetime than 1000 h at temperatures above 100 °C. For quantitative evaluation of tritium concentration in low-level tritiated water such as environmental water, the tritium enrichment by a solid polymer electrolysis (SPE) method is required prior to the tritium concentration measurements. The SPE device composed of PEEK-PEMs with IECs of 0.9–1.2 mmol/g showed a tritium enrichment ratio of 1.35 at 30 °C, which is 20% higher than that of Nafion. Higher tritium enrichment ratios in PEEK-PEM are explained by the smaller amount of transported water. The water transport coefficient in PEEK-PEM is ～1, which is a half value of Nafion. In addition, the water transport coefficient of PEEK-PEM shows less temperature dependence, at least, up to 60 °C. These features have advantages in electrolytic enrichment of tritium for practical use.