Analysis of the relationship between DBH and crown projection area using a new model

Relations of DBH-crown projection area (CPA) were studied for deciduous and coniferous trees with different models, one of which is newly derived this time. For DBH-CPA relations, a proposed power-sigmoid function was the most suitable one among four models because of its good fit and mechanistic meaning. This model contains the feature that CPA grows with the second power relation to DBH, and the increasing rate of CPA slows as DBH increases. With transformation, the power-sigmoid function for DBH-CPA relation can be applied for individual basal area (IBA)-CPA relations as single-saturate function, and these two functional models have high compatibility. Next, the differences of DBH-CPA between deciduous and coniferous tree groups were analyzed with power-sigmoid function. The initial increasing rates of CPA against DBH for each group were similar, though the CPA's increasing rate for the coniferous group tended to decrease earlier than for the deciduous group. Because the power sigmoid function has mechanistic meanings, one can separately analyze the attributes of the DBH-CPA relation: the initial increasing rate of CPA and final tree form.     

Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.     

Effect of lectins on the transport of food factors in caco-2 cell monolayers

The effect of three plant lectins, soybean lectin (SBA), Japanese jack bean lectin (CGA), and wheat germ lectin (WGA), on the transport of various food factors, such as isoflavones, quercetin, dipeptides, and calcium ions, were investigated by use of an intestinal tract model, Caco-2 cell monolayers. The lectins increased the isoflavone transport but had no effect on aglycon transport. SBA increased the transport of quercetin glycosides, whereas CGA and WGA had no effect. The lectins increased the transport of calcium ions but showed no effect on the transport of dipeptides, carnosine, and anserine. Although SBA did not change the transepithelial electrical resistance (TER) value of the Caco-2 cell monolayers, CGA and WGA decreased the TER value. These results indicate that plant lectins affect the transport of food factors in different manners, presumably due to their specific sugar binding activity.     

Glutamate dehydrogenase in higher plants

The occurrence of NADPH-dependent glutamate dehydrogenase (GDH) was studied in higher plants. All of the higher plants tested had both NADH- and NADPH-dependent GDH activities, based on the following observations: 1) NADPHdependent GDH activity was found in the extracts of corn and soybean leaves, which was free of NADPH-dehydrogenase by heat treatment or DEAE-cellulose column chromatography. 2) Radish leaves and roots grown under germ-free condition showed the same NADPH-dependent GDH activity as those grown under conventional condition. 3) No conversion of NADPH to NADH in the reaction mixture was demonstrated by measuring alcohol dehydrogenase activity. Moreover, it was ascertained that rice plant cells grown on suspension culture had 50% of NADPH-dependent GDH activity, and both activities were not affected by nitrogen sources.     

Physical, chemical, and biological properties of s-allylcysteine, an amino acid derived from garlic.

Physical, chemical, and biological properties of S-allylcysteine (SAC) were investigated. SAC showed stable properties under tested conditions, and its acute/subacute toxicity was very minor in mice and rats (LD(50) value >54.7 mM/kg po; >20 mM/kg ip). The pharmacokinetics of SAC was investigated after oral administration of garlic supplement containing SAC to human volunteers. SAC from garlic consumption was rapidly absorbed from the gastrointestinal tract, however, the half-life and excretion time were more than 10 h and 30 h, respectively.     

Semiquantitative determination of imogolite and Al-rich allophane (Si / Al ≃ 1 : 2) in some volcanic ash soils in San'in region by a combination of thermogravimetry-differential thermal analysis and trimethylsilylation analysis of soil clays

Abstract

A method to determine the contents of imogolite and Al-rich allophane (Sil Al ? 1 : 2) in volcanic ash soils was presented. The method is based on the (1) assessment of the presence of Al-rich allophane in clays by successsive extraction with dithionite-citrate and oxalate-oxalic acid, (2) trimethylsilylation of soil clay with a mixture of hexamethyldisiloxane, HCl, and isopropyl alcohol, and determination of the content of monomeric Si based on the trimethylsilyl derivative of monomeric orthosilicate anion by gas / liquid chromatography, (3) determination of the total content of imogolite and Al-rich allophane based on the content of monomeric Si from imogolite, (4) determination of the imogolite content by Thermogravimetry (TG )-Differential Thermal Analysis (DTA) based on the weight loss due to endothermic dehydroxylation with maximum values at ca. 386°C, (5) calculation of the Al-rich allophane content by subtracting the imogolite content from the total content of these minerals, and (6) evaluation of the imogolite and Al-rich allophane content of soil by multiplying clay content of soil and the two mineral content of clay. The trimethylsilylation analysis was found to be reproducible, and the estimated total amounts of two minerals in clays by this method were adequately approximated to those evaluated from the amount of Si (= Si_o) extracted with oxalate-oxalic acid after extraction with dithionite-citrate. The variation in the abmldance of two minerals in the soil horizons of volcanic ash soils from the San'in region indicated that this method is suitable for the profile-study of volcanic ash soils.