The effect of alkaline dust decline on the precipitation chemistry in northern Japan

The precipitation chemistry in northern Japan, especially Hokkaido, has been investigated since 1982. This area has often been found to have high concentrations of alkaline road dust (asphalt dust) in the air, caused by the use of studded tires during the winter. It is well known that the composition of precipitation in these areas is often dominated by asphalt dust including calcium bicarbonate. However, recently the concentration of asphalt dust in the air has decreased owing to a ban on the use of studded tires. Simultaneously, in precipitation, the lowering of pH values and the increase of hydrogen ion depositions have been occurring owing to the decrease of non-sea-salt calcium ions (nss-Ca²⁺) concentrations and depositions derived from asphalt dust. In addition, we found that a decrease of nss-Ca²⁺ firstly leads to a decrease of bicarbonate ions (HCO₃ ^?), the counter ion to nss-Ca²⁺ in asphalt dust. Therefore, the increase of H⁺ concentrations and depositions was great in comparison with the decrease of nss-Ca²⁺ concentrations and depositions in areas where the HCO₃ ^?concentrations, varied by pH, and depositions had been low. Furthermore, this variation was mainly observed in the ionic composition of snow cover and snowfall at sites along the Japan Sea in northern Japan during winter. In this area, the Acid Shock effect may become a serious problem from the decline of pH values in melting snow. Moreover, we found that ammonium ions and non-sea-salt sulfate ions depositions have also been decreasing in response to a decrease of nss-Ca²⁺ depositions, derived from asphalt dust. It seems that this phenomenon is caused by the decrease of asphalt dust concentrations in the air.     

Improved storage stability of model infant formula by whey peptides fractions

The purpose of this study was to evaluate the shelf-life stability (6 months) of model infant formula with whey protein hydrolysates or peptidic fractions as carrageenan replacers. Whey protein hydrolysates were prepared with trypsin and followed by ultrafiltration of the hydrolyzed mixture, and peptidic fractions were isolated from the ultrafiltered tryptic hydrolysate by anion- or cation-exchange chromatography. The stability of the model infant formula was evaluated using a stratification method based on fat content differences between the top and bottom strata of the samples. With protein hydrolysate-based formulations, the creaming rate of the fat in the product was slightly higher than in the standard formulation (with carrageenan), which is indicative of lower storage stability. The addition of cationic fractions to model infant formula also resulted in lower product stability, whereas the fat creaming rate was retarded in anionic fraction based formulations. The physicochemical characteristics of certain peptides combined with the reported high emulsifying properties of peptidic sequences found within these fractions may account for their ability to act as carrageenan replacers.     

Effect of food reductones, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and hydroxyhydroquinone (HHQ), on lipid peroxidation and type IV and I allergy responses of mouse

The effect of long-term supplementation of food reductones, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) (2%, w/w), detected in many foodstuffs including soy sauce, and hydroxyhydroquinone (1,2,4-benzenetriol) (HHQ) (1.2%, w/w), detected in coffee, on mouse lipid peroxidation and type IV and I allergy responses was investigated. The effect of supplementation of these reductones combined with NO(2) inhalation (5-6 ppm) was also investigated. Levels of thiobarbituric acid-reactive substances in lung were remarkably increased, and those in kidney and liver were slightly decreased by supplementation of DMHF or HHQ. The degree of 2,4-dinitrochlorobenzene (DNCB)-sensitized lymph node cell proliferation as assessed by lymph node assay was remarkably enhanced by supplementation of DMHF or HHQ. Both the DNCB-sensitized and the trimellitic anhydride-sensitized increases in IgE levels of mice were enhanced to greater extent by supplementation of DMHF or HHQ. In no cases were additive effects of NO(2) inhalation observable. Allergen-sensitized type IV and I allergy responses of mice may be enhanced by supplementation of food reductones, DMHF or HHQ.     

Estimation of natural pollution loads from streamflow measurements in remote catchments

In a study conducted in Marmot Creek Basin (total area 9.40 kmz) situated in the Rocky Mountains of Alberta, equations were developed to obtain gross estimates of the total inorganic solutes dislodged from three forest catchments on a monthly and annual basis. The r ² range of the equations was 99% or greater, indicating excellent fit in all cases. The equations are suitable for in situ estimation of the pollution loads directly from streamflow measurements, especially for remote catchments.     

Mechanisms of stabilization of earthworm casts and artificial casts

Summary Fresh casts were collected from the earthworm species Aporrectodea caliginosa, and artificial casts were also made. The casts were subjected to ageing, drying-rewetting, and sterilization by hexanol vapour. Clay dispersion was determined, as a measure of the lack of stability of the casts. Two soils were used, the topsoil of a recently reclaimed polder soil in the Netherlands and the topsoil from a South Australian duplex soil. For both soils the fresh worm casts had higher dispersible clay than the artificial casts. During ageing, both types of casts became more stable. There are strong indications that this was mainly due to changes on the surface of the casts. Fungi developed on the surface of 6-day-old worm casts made of Australian soil. This gave a higher stability to the casts compared to artificial casts of the same age without fungal growth. With both types of casts, hexanol inhibited fungal growth on the surface of the casts, reducing the stabilizing effect of ageing. The fungus did not develop on Dutch soil casts until after 42 days, and the development of a higher stability with age was also less marked than in the Australian soil. When the casts were subjected to a drying and rewetting cycle before analysis, they became much more stable than the casts that were analyzed wet. The drying-rewetting cycle removed most of the differences between the worm casts and the artificial casts, and also removed any effects of ageing.Dedicated to the late Prof. Dr. W. Kühnelt     

Purification and characterization of an isoflavone-conjugates-hydrolyzing beta-glucosidase from endophytic bacterium

An isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) from endophytic bacterium, Pseudomonas ZD-8 was purified to homogeneity by successive ammonium sulfate precipitation, gel filtration on SephadexG-100, DEAE-sephrose CL-6B and DEAE-Sephacel chromatography. The enzyme was a monomeric protein with an apparent molecular mass of 33 kDa as determined by SDS-PAGE and gel filtration. It was optimally active at pH 6.0 and 40 degrees C and had a specific activity of 1485 U mg of protein(-1) against genistin. The ICHG readily hydrolyzed rho-nitrophenyl-beta-glucoside, rho-nitrophenyl-beta-galactoside, genistin, daidzin, with Km values of 1.64, 1.87, 0.012, 0.014 mM, respectively. The ICHG showed a pronounced specificity for glucose in the 7-position of isoflavone and flavone conjugates and hydrolyzed effectively malonyl isoflavone glucosides as well as isoflavone glucosides with similar kinetics. Glucose and glucono-delta-lactone inhibited the enzyme competitively with Ki values of 84 mM and 23 mM, respectively. The enzyme did not require divalent cations for activity, and its activity was strongly inhibited by Hg2+, Ag+, rho-chloromercuribenzoate, iodoacetic acid, and N-ethylmaleimide while reducing agents such as beta-mercaptoethanol, dithiothreitol, dithioerythritol, glutathione slightly activated the enzyme.     

Non-pathogenic Fusarium strains protect the seedlings of Lepidium sativum from Pythium ultimum

Two root-colonizing Fusarium strains, Ls-F-in-4-1 and Rs-F-in-11, isolated from roots of Brassicaceae plants, induced the resistance in Lepidium sativum seedlings against Pythium ultimum. These strains caused an increase in the content of benzyl isothiocyanate, and of its precursor glucotropaeolin, in the roots of the host plants. The increased isothiocyanate content is one of the factors contributing to the resistance of L. sativum against P. ultimum. To be transformed into the fungitoxic compound benzyl isothiocyanate, glucotropaeolin has to be hydrolyzed by myrosinase, which can be produced either by plants or microorganisms. The Fusarium strain Ls-F-in-4-1 has a myrosinase activity but the strain Rs-F-in-11 has not. These results suggest that both strains are able to trigger the metabolic pathway leading to benzyl isothiocyanate production in the plant. In the case of the myrosinase-negative strain Rs-F-in-11, hydrolyzation into isothiocyanate is only due to the myrosinase activity of the plant, and in the other case, the myrosinase produced by the strain Ls-F-in-11 also would contribute to the production of isothiocyanate. This paper reports a new mode of action of non-pathogenic Fusarium strains in controlling P. ultimum.