Determination of peroxide value by the colorimetric iodine method with protection of iodide as cadmium complex

Improved procedures of the Swoboda and Lea method for the determination of peroxide values (POV) of fats and lipids are presented. After oxidation of iodide to iodine with the sample for 5 min under an inert atmosphere, an excess of the iodide ion is immediately converted to cadmium complex for protection from atmospheric oxygen. The iodine is measured colorimetrically at 358 or 410 nm, and POV is calculated from the absorbance. This method permits the rapid determination of POV with a small amount of sample at a moderate cost using usual glasswares. For the analysis of lipids in biological materials or food products, the chloroform solution obtained by the Bligh and Dyer method is directly subjected to this procedure without evaporation of the solvent. Conversions between POV obtained by the different methods are discussed.     

Influence of Solid Fraction on the Optimum Molecular Weight of Polymer Dispersants in Aqueous TiO2 Nanoparticle Suspensions

The effects of solid fraction and molecular weight of a polymer dispersant—sodium polyacrylate—on the apparent viscosity of an aqueous TiO₂ nanoparticle suspension were investigated by varying the particle solid fractions from 15 to 37 vol% and the molecular weight of the dispersant from 1200 to 30 000. When the solid fraction was increased, the molecular weight of the dispersant was decreased to obtain the lowest suspension viscosity. The effect of the molecular weight of the dispersant on the suspension viscosity was discussed based on the surface interaction between TiO₂ particles characterized by a colloid probe atomic force microscope. The polymer dispersant adsorbed on a particle surface enhanced the repulsive force between the TiO₂ particles and reduced adhesion by electrosteric interaction, which reduced the suspension viscosity. The size of the dispersant in the aqueous solution determined by a dynamic light scattering method was compared with the estimated particle surface distance. As the solid fraction increased, the average surface distance and the size of the dispersant attainable to the particle surface reduced; therefore, the optimum molecular weight of the dispersant for a dense suspension is also reduced.     

Cotesia glomerata Female Wasps Use Fatty Acids from Plant–Herbivore Complex in Host Searching

Cotesia glomerata parasitizes early instars of the cabbage butterfly,Pieris rapae, in Japan. Female wasps antennatedRorippa indica leaves damaged by feeding ofP. rapae larva, but ignored artificially damaged leaves. Females also antennated filter paper containingR. indica leaf juice plusP. rapae regurgitant. Chemical analysis revealed five compounds in higher amounts in the infested edges of leaves than in artificially damaged edges. Among them, we identified palmitic acid, oleic acid, and stearic acid. Female wasps antennated filter paper containing each of these three acids. We discuss the function of these acids in the tritrophic context.     

Postmortem changes in bovine troponin T isoforms on two-dimensional electrophoretic gel analyzed using mass spectrometry and western blotting: The limited fragmentation into basic polypeptides

To comprehend postmortem changes in troponin T (TnT), whole beef proteins were developed on a two-dimensional electrophoretic gel. Multiple TnT-related spots were identified by both western blotting and MALDI-TOF MS utilizing bovine TnT isoform mRNA sequences. More than 10 TnT fast-type isoform spots (pI 5.7-9.6<) and the two slow-type isoform spots (pI 5.6-5.7) were observed at slaughter. All the isoforms were degraded exclusively into basic spots (pI 9.6<) at day 14 postmortem. Some TnT-related phosphorylated spots present at slaughter had disappeared by day 14, suggesting that the phosphorylated N-terminal region was cut off during beef aging. The intact isoforms and the fragments were identified by the MS with sequence coverage of 20.8-62.7%, and two of the fragments included the cutting site peptide of a conventional 30kDa or of a slow TnT-derived fragment. These results revealed that all of the TnT isoforms are cut exclusively in the glutamic acid-rich amino-terminal region during postmortem aging.     

Recovery of heavy metals from MSW molten fly ash by carrier-in-pulp method: Fe powder as carrier

Municipal solid waste (MSW) molten fly ash is classified as a hazardous waste because it contains considerable amount of heavy metals, which pose environmental concern due to their leaching potential in landfill environment. This study proposes carrier-in-pulp (CIP) method as a new hydrometallurgical route to extract and recover Pb, Zn, Cu, and Cd from molten fly ash before landfilling. In this method, a carrier material, which recovers the extracted metals, is added simultaneously with fly ash to a leaching solution and is harvested from the pulp by physical separation method, such as magnetic separation or sieving.To demonstrate the effect of the CIP method, shaking flask experiments were conducted under various conditions using NaCl solution, iron powder as carrier, and molten fly ash. More than 99 wt% Pb, Zn, and Cd, and 97 wt% Cu were extracted from the ash. However, only Pb and Cu were recovered (96.3 wt% Pb and 94.3 wt% Cu) by the iron powder through cementation, leaving behind Zn and Cd ions in the solution phase. The leaching test conducted on the treated fly ash residue revealed that the CIP method suppressed the solubilization of Pb to a value below the landfill disposal guideline.     

Promotive effect of auxins on UDP-glucose: flavonol glucosyltransferase activity in Vitis sp. cell cultures

The addition of 2,4-dichlorophenoxyacetic acid (2, 4-D) to Vitis sp. cell cultures significantly enhanced the production of quercetin 3,7,4′-tri-O-glucoside, 3,7-di-O-glucoside and 3,4′-O-glucoside from quercetin. This enhancement of glucosylation by 2,4-D was also observed in cell cultures of other plant species. The activity of UDP-glucose: flavonol glucosyltransferase (UFGT) in cell-free extracts of Vitis sp. cell cultures increased approximately 10-fold, 48 h after the addition of 2,4-D to the culture medium. The UFGT activity increased linearly up to 15 h and showed a maximal response to the addition of 10–50 mg/l of 2,4-D at 48 h. The promotive effect of 2,4-D was inhibited by cycloheximide suggesting that de novo protein synthesis was involved in this phenomenon. Interestingly, similar promotive effects on the UFGT activity were observed for other phytohormones such as kinetin and several anti-auxins.     

Unique Glycoform-Dependent Monoclonal Antibodies for Mouse Mucin 21

Mucin 21(Muc21)/epiglycanin is expressed on apical surfaces of squamous epithelia and has potentially protective roles, which are thought to be associated with its unique glycoforms, whereas its aberrant glycosylation is implicated in the malignant behaviors of some carcinomas. Despite the importance of glycoforms, we lack tools to detect specific glycoforms of mouse Muc21. In this study, we generated two monoclonal antibodies (mAbs) that recognize different glycoforms of Muc21. We used membrane lysates of Muc21-expressing TA3-Ha cells or Chinese hamster ovary (CHO)-K1 cells transfected with Muc21 as antigens. Specificity testing, utilizing Muc21 glycosylation variant cells, showed that mAb 1A4-1 recognized Muc21 carrying glycans terminated with galactose residues, whereas mAb 18A11 recognized Muc21 carrying sialylated glycans. mAb 1A4-1 stained a majority of mouse mammary carcinoma TA3-Ha cells in vitro and in engrafted tumors in mice, whereas mAb 18A11 recognized only a subpopulation of these. mAb 1A4-1 was useful in immunohistochemically detecting Muc21 in normal squamous epithelia. In conclusion, these mAbs recognize distinct Muc21 epitopes formed by combinations of peptide portions and O-glycans.     

Development of moulded pulp materials for the packaging of electronic equipment

A new shredded pulp–plastic microsphere composite with modified starch binder which is applicable to the packaging of electronic equipment has been developed. This composite with a 3 wt% microsphere content has almost the same compressive stress at 50% compressive strain as that of (poly)styrene foam, which has a specific gravity of 0.025. A moulded sample of the above composites can be released from a mould after 1.5 minutes of steam heating, the same cycle time as that of styrene foam. © 1997 John Wiley & Sons, Ltd.