Showing papers by "Utsunomiya University published in 1998"

Development of genotoxicity assay systems that use aquatic organisms

Abstract: Our aim is to develop and evaluate monitoring systems that use aquatic organisms to assess the genotoxicity of water in the field and in the laboratory. In a field study, we have shown that the micronucleus assay is applicable to freshwater and marine fishes and that gill cells are more sensitive than hematopoietic cells to micronucleus-inducing agents. Gill cells from Carassius sp. (Funa) and Zacco platypus (Oikawa) collected upstream on the Tomio River (Nara, Japan), tended to have lower micronucleus frequencies than gill cells from fish collected at the midstream of the river. Leiognathus nuchalis (Hiiragi) and Ditrema temmincki (Umitanago), small marine fishes collected periodically at Mochimune Harbor (Shizuoka, Japan), showed seasonal differences in the frequencies of micronucleated gill cells and erythrocytes; they were highest in summer. For laboratory studies, we developed a method for analyzing chromosomal aberrations and micronuclei using Rhodeus ocellatus ocellatus (rose bitterling) embryos. One day after artificial insemination (gastrula stage), we observed structural chromosomal aberrations and micronuclei in the cells of embryos grown in water containing trichloroethylene. Although more work is needed to fully assess their sensitivity, these assays show promise as a means of detecting environmental genotoxins.

Monodisperse Two-Dimensional Nanometer Size Clusters of Partially Fluorinated Long-Chain Acids

Abstract: Two-dimensional molecular clusters of a few tens nanometer size were found in spread monolayers of a series of partially fluorinated long-chain acids. Atomic force microscopy images have revealed that the size of the clusters is sharply monodisperse. The size changes systematically with changing structure of the hydrophobic chain of the amphiphiles. The smallest cluster has a circular shape of 17 nm diameter. One cluster is composed of about 700 film molecules. These clusters gather to form macroscopic domains of millimeter size without compression. A formation mechanism of these molecular clusters is discussed. Clusters are formed during the spreading process due to the instability of the film materials at the spreading process. It was made clear that cluster formation during the spreading is rather general for amphiphiles under the conditions where condensed monolayers are formed.

Observations of TeV Gamma Ray Flares from Markarian 501 with the Telescope Array Prototype

Abstract: We report the observations of TeV gamma-ray flares from Markarian 501 using the Telescope Array Prototype. The observations were carried out continuously from the end of March to the end of July of 1997. The energy spectrum and the time variation of the gamma-ray intensities are shown. The intensity has been changed by an order of magnitude in this period, and the possible quasi-periodic oscillation of 12.7 days were discovered.

Gel Formation from Industrial Milk Whey Proteins under Hydrostatic Pressure: Effect of Hydrostatic Pressure and Protein Concentration

Abstract: The effects of high hydrostatic pressure and protein concentration on the denaturation and gelation of whey protein were investigated. Industrial whey protein isolate (WPI) and whey protein concentrate (WPC) solutions (pH 6.8) at various concentrations were pressurized for 10 min at 30 degrees C under 200-1000 MPa. With the WPI solution, the concentration for affecting the turbidity was 1% and was 6% for the viscosity at 400 MPa, while for inducing gelation, it was 10% at 600 MPa. With the WPC solution, the viscosity changed at a concentration >12%, and gel formation began at >18% at 400 MPa. The hardness and breaking stress of pressure-induced WPI gels increased with increasing concentration of WPI (12-18%) and hydrostatic pressure, the ratings for the 20% WPC gels being one-third those of the 20% WPI gels. The solubility of proteins from the pressure-induced WPI gels decreased with increasing pressure, while that of WPC gel induced at >600 MPa remained constant at approximately 50%. The microstructure of the WPI gels had a porous network form, whereas the WPC gels were irregular particulates. beta-Lactoglobulin, alpha-lactalbumin, and serum albumin preferentially participated in pressure-induced aggregation and gelation through S-S bonding.

Lack of promoting effects of the electromagnetic near-field used for cellular phones (929.2 MHz) on rat liver carcinogenesis in a medium-term liver bioassay.

Abstract: The possible cancer promotion potential of local exposure to a pulse modulated 929.2 MHz electromagnetic near-field on chemically-initiated rat liver carcinogenesis was investigated employing a medium-term bioassay. A 929.2-MHz electromagnetic near-field of time division multiple access (TDMA) signal for PDC (Personal Digital Cellular, Japanese cellular telephone standard) system was directed to rats through a quarter-wavelength monopole antenna. Maximum local specific absorption rates (SARs) on temporal average were 7.2-6.6 W/kg within the whole body and 2.0-1.7 W/kg within the liver, which was the target organ. The whole-body average SARs on temporal average were 0.80-0.58 W/kg. Temporal peak SARs had three times these values due to the duty ratio of the PDC signal. Exposure was for 90 min a day, 5 days a week, over 6 weeks. The exposure apparatus was specially designed for this experiment, to allow exposure of the lateral mid-section of the rat body to the electromagnetic near-field. Male F344 rats, 6 week-old, were initially (at week 0) given a single dose of diethylnitrosamine (DEN, 200 mg/kg body wt, i.p.). At 2 weeks later, exposure (48 rats) or sham-exposure (48 rats) was started. The exposure of electromagnetic near-fields was performed using the exposure apparatus mentioned above. At week 3, all rats were subjected to a 2/3 partial hepatectomy. At week 8 (i.e. after 6 weeks exposure or sham-exposure), the experiment was terminated and all rats were killed. Carcinogenic potential was scored by comparing the numbers and areas of the induced glutathione S-transferase placental form (GST-P) positive foci in the livers of the exposed and sham-exposed rats. A further group of 24 animals, given only DEN and partial hepatectomy, served as the controls. The numbers (no./cm2) of GST-P positive foci were 4.61 +/- 1.77, 5.21 +/- 1.92 (P < 0.05, versus control) and 4.09 +/- 1.47 and the areas (mm2/cm2) were 0.30 +/- 0.16, 0.36 +/- 0.21 and 0.28 +/- 0.15, for the exposed, sham-exposed and control groups, respectively. There were no significant differences between the exposed and sham-exposed groups. These findings clearly indicated that local body exposure to a 929.2-MHz field, modulated in a PDC waveform, has no significant effect on rat liver carcinogenesis under the experimental conditions employed.

Cotylenins and Fusicoccins Stimulate Seed Germination of Striga hermonthica (Del.) Benth and Orobanche minor Smith

Abstract: Several fungal metabolites were examined for their effects on germination of the root parasitic weeds witchweed, Striga hermonthica (Del.) Benth, and clover broomrape, Orobanche minor Smith. Among ...

The 1.5 GHz electromagnetic near-field used for cellular phones does not promote rat liver carcinogenesis in a medium-term liver bioassay

Abstract: We have recently established that local exposure to a 929.2 MHz electromagnetic near-field, used for cellular phones, does not promote rat liver carcinogenesis in a medium-term bioassay system. In the present study, a 1.439 GHz electromagnetic near-field (EMF), another microwave band employed for cellular phones in Japan, was similarly investigated. Time division multiple access (TDMA) signals for the Personal Digital Cellular (PDC) Japanese cellular telephone standard system were directed to rats through a quarter-wavelength monopole antenna. Numerical dosimetry showed that the peak SARs within the liver were 1.91-0.937 W/kg, while the whole-body average specific absorption rates (SARs) were 0.680-0.453 W/kg, when the time-averaged antenna radiation power was 0.33 W. Exposure was for 90 min a day, 5 days a week, over 6 weeks, to male F344 rats given a single dose of diethylnitrosamine (200 mg/kg, i.p.) 2 weeks previously. At week 3, all rats were subjected to a two-thirds partial hepatectomy. At week 8, the experiment was terminated and the animals were killed. Carcinogenic potential was scored by comparing the numbers and areas of the induced glutathione S-transferase placental form (GST-P)-positive foci in the livers of exposed (48) and sham-exposed rats (48). Despite increased serum levels of corticosterone, adrenocorticotropic hormone (ACTH) and melatonin, the numbers and the areas of GST-P-positive foci were not significantly altered by the exposure. These findings clearly indicated that local body exposure to a 1.439 GHz EMF, as in the case of a 929.2 MHz field, has no promoting effect on rat liver carcinogenesis in the present model.

Characterization and Distribution of Soils at Lambir Hills National Park in Sarawak, Malaysia, with Special Reference to Soil Hardness and Soil Textures

Abstract: For the rehabilitation of the degraded and abandoned land in the tropical area, it needs to define the various characteristics of remaining natural forests. This work was done to find out a physical hazard for root elongation of plant at Lambir Hills National Park, Miri, Sarawak, Malaysia, with special reference to soil hardness and soil texture. Furthermore, soil moisture and soil temperature were monitored at the hill ridge and at the valley to show their annual fluctuation. Soil physico-chemical properties at the hill ridge and the valley were also investigated. At the hill ridge, well-developed soils with a deep solum were found. Organic matter content was high only at the surface horizon (0-5 cm) where a root mat develops. Although soil moisture content fluctuated significantly, the soil was dry throughout the monitoring period. On the other hand, at the valley, soil moisture content was relatively stable even after the frequent rainfall. The small particles and nutrients at the valley have been brought by the continuous water and eroded particles supply from surroundings. Based on the topographical investigation, the study area was roughly divided into 3 categories: 1) Steep slope area : Soil and vegetation status may be often affected and modified by the land slide or soil erosion. Soil texture was sandy loam, loamy sand, or loam. Gravelly materials often appeared in the subsurface layer at the depth of 20-40 cm, which are hard for root to penetrate into. This layer can be regarded as the one with physical hazard against root penetration. 2) Gentle slope area : Soil and vegetation status are relatively stable for a long time. Soil texture was light clay or heavy clay. Transported clayey materials were accumulated to a depth below 20 cm, and/or the in-situ weathering in the deeper part could have occurred because of the relatively stable topography. 3) Ridge area : Although soil and vegetation status looks stable in view of topography, moisture condition much fluctuated. Soil texture was clay loam or sandy clay loam, which was the middle range between that of a steep slope area and a gentle slope area. The physical hazard in the soil might not be found, but the rates of root elongation and plant growth may be slow since the soil is prone to be dry.

Affinity of Antioxidative Polyphenols for Lipid Bilayers Evaluated with a Liposome System

Abstract: We developed a method to measure the amounts of antioxidative polyphenols and ubiquinones incorporated into the lipid bilayers of liposomes to estimate their affinities for cell membranes Results were expressed in terms of an “affinity factor”, calculated by division of the amount of compound incorporated by the amount added to the liposomal solution The results reflected dose-dependence of the biological activities of the compound found in earlier in vitro experiments with mammalian and bacterial cells

Antimutagenic properties of 3,5-disubstituted 2-thiohydantoins

Abstract: 3,5-Disubstituted 2-thiohydantoins, which were prepared by the reaction of allyl isothiocyanate (AITC) or 4-(methylthio)-3-butenyl isothiocyanate (MTBI) with various amino acids, were assayed for their inhibitory effects on the mutagenicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) on Salmonella typhimurium TA 98. When the 3,5-disubstituted 2-thiohydantoins (125−500 μg/mL) were simultaneously preincubated with the bacterial strain, IQ (0.5 μg/mL), and rat microsomal fraction (S9 mix) for 20 min, a dose-dependent inhibition of IQ mutagenicity was observed in the tested compounds except one prepared from MTBI and l-methionine. This inhibition ranged from 23% to 86%. The inhibitory effect either disappeared or was largely reduced to 5−19%, when the 3,5-disubstituted 2-thiohydantoins were added after metabolic activation of IQ with S9 mix. These results suggest that the 3,5-disubstituted 2-thiohydantoins probably acted as an inhibitor of the S9 mix-mediated metabolic activation of the mutagen. Keywords:...

Pyridovericin and pyridomacrolidin: novel metabolites from entomopathogenic fungi, Beauveria bassiana.

Abstract: program, we systematically investigated the diversity of metabolites in Deuteromycota, Beauveria bassiana, Metarhizium anisopliae, Nomuraea rileyi, Paecilomyces fumosoroseus and Verticillium lecanii, which have been isolated from the corpses of insects. Comparative study of the HPLC elution pattern among fungal metabolites found that a strain, Beauveria bassiana EPF-5, produced two novel metabolites, designated pyridovericin (1) and pyridomacrolidin (2). In this communication, we preliminarily report the production, isolation, structure and biological activities of 1 and 2. The detection of fungal metabolites by HPLC analysis was performed under the following conditions: column: ODS column (Senshu Pak PEGASIL); solvent: a linear gradient 50% MeOH to 70% MeOH for 50 minutes; UV detection at 220nm, 254nm and 310nm; flow rate of 3.0ml/minute. Beauveria bassiana EPF-5, a strain isolated from an adult Mulberry small weevil (Baris

The Structures of Pyridovericin and Pyridomacrolidin, New Metabolites from the Entomopathogenic Fungus, Beauveria bassiana

Abstract: Entomopathogenic fungi seem to be interesting as a source of biologically active compounds such as an insecticides1) and immunosuppressants2,3), because all insect orders are susceptible to fungal diseases. With the goal of finding novel bioactive compounds from fungi, we investigated metabolite diversity using an HPLC screening program. During the screening process, we isolated two novel metabolites named pyridovericin (1) and pyridomacrolidin (2) (Fig. 1) from the mycelial cake of the entomopathogenic fungus, Beauveria bassiana EPF-54). In this paper, we describe the physico-chemical properties and structural determination of 1 and 2. Structure of Pyridovericin (1) The physico-chemical properties of 1 and 2 are summarized in Table 1. The molecular formula of 1 was determined to be C21H23NO5 [Found m/z 369.1580 (M+), Calcd for C21H23NO5 369.1576] by highresolution EI-MS measurement. The IR spectrum (KBr) suggested the presence of the hydroxy group (3403cm-1), amide carbonyl (1661cm-1) and hydrogen bonded carbonyl (1611cm-1), respectively. The 13C NMR spectrum of 1 accounts for the presence of 21 carbon signals. The analyses of 1H NMR and

Solubilization and chemical characterization of an insoluble matrix protein in the gastroliths of a crayfish, Procambarus clarkii

Abstract: The gastrolith of the crayfish Procambarus clarkii contains a small amount of an organic matrix that is mainly chitin and proteins, together with a large amount of calcium carbonate. As the first step to understand the mechanism of calcification, we tried to characterize matrix proteins in the gastrolith. An insoluble matrix protein, referred to as gastrolith matrix protein, was made soluble with 1% SDS containing 10 mM dithiothreitol, and was purified by reverse-phase high-performance liquid chromatography. The protein had a molecular weight of about 50,500 and a blocked amino terminus. By enzymatic digestion and microsequencing, five partial amino acid sequences with a total of 225 amino acid residues were identified and found to include a repetitive sequence not reported previously.

Decrease of the Obese Gene Expression in Bovine Subcutaneous Adipose Tissue by Fasting

Abstract: The expression of mRNA of leptin, the product of the obese gene, in bovine adipose tissue was analyzed by a lysate RNase protection assay. The mRNA level was significantly decreased by food deprivation for two days and partially recovered after 3 hr of refeeding, indicating that obese gene expression in the ruminant was regulated by feeding.

Allometry, root/shoot ratio and root architecture in understory saplings of deciduous dicotyledonous trees in central Japan

Abstract: Plant allometry that is related to plant architecture and biomass allocation strongly influences a plant’s ability to grow in shaded forest understory. Some allometric traits can change with plant size. The present study compared crown and trunk allometries, root/shoot biomass allometry, and root architecture among understory saplings (0.25--5m height, except for two trees > 5 < 7 m) of seven deciduous dicotyledonous species in central Japan. Associations of the crown and trunk allometries with several plant morphological attributes were analyzed. Branch morphology (plagiotropyvs orthotropy) and life size were correlated with sapling crown and trunk allometries. Both large leaves and orthotropic branches were associated with a narrow small crown and slender trunk. The root/shoot ratio decreased rapidly with increasing plant height for saplings shorter than about 1.5 m. Less shade-tolerant species tended to have smaller root/shoot ratios for saplings taller than 1.5 m. With an increase in plant height, the branch/trunk biomass ratio decreased for saplings with plagiotropic branches but increased for saplings with orthotropic branches. Four subcanopy species (Acer distylum, Carpinus cordata, Fraxinus lanuginosa and Acanthopanax sciadophylloides) had superficial root systems; a common understory species (Sapium japonica) had a deep tap root system; and a canopy species (Magnolia obovata) and a subcanopy species (Acer tenuifolium) had heart root systems of intermediate depth. The root depth was not related to shade tolerance. Among species of the same height, the difference in fine root length can be 30-fold.

An effective method for isolating alginate lyase-producing Bacillus sp. ATB-1015 strain and purification and characterization of the lyase.

Abstract: A new alginate lyase-producing micro-organism, designated as Bacillus sp. strain ATB-1015, was effectively isolated from soil samples pretreated for 3 months with a substrate of the enzyme, sodium alginate. Alginate lyase activity was assayed by the degrading activity of biofilm on Teflon sheet discs, which was formed by a mucoid strain of Pseudomonas aeruginosa PAM3 selected from clinical isolates. The extracellular alginate lyase was precipitated with ammonium sulphate from the culture broth, and purified by gel filtration and anion exchange chromatography. The molecular weight of the lyase was estimated to be 41 kDa by SDS polyacrylamide gel electrophoresis and Sephacryl S-200 HR column chromatographic. The optimum pH and temperature for the enzyme activity were around 7.5 and 37°C, respectively, and the Km value was 0.17% with the substrate, sodium alginate. The lyase activity was completely inhibited by treatment with 1 mmol l -1 of EDTA and the decreased activites was almost completely recovered by the addition of 2 mmol l -1 of CaCl 2 . The activites was not affected by treatment with the protein denaturants, 0.01 mol l -1 of SDS or 1 mmol l -1 of urea. The lyase had substrate specificity for both the poly-guluronate and poly-mannuronate units in the alginate molecule.

Spotsize contraction in standard single-mode fibers by use of a GI-fiber tip with a high focusing parameter

Abstract: A spotsize reducer for single-mode fibers (SMFs) was fabricated by use of the quarter-pitch length of a parabolic-index fiber tip having a high focusing parameter. The modal-field diameter of a standard SMF at a wavelength of 1.55 /spl mu/m has been reduced from 10.4 to 5.8 /spl mu/m, with the use of the tip. The reducer appears promising for low-loss coupling between standard SMFs and various waveguides, such as dispersion compensated fibers, erbium-doped fibers, and planar waveguides.

Brightness-to-luminance ratio of colored light in the entire chromaticity diagram

Abstract: Brightness-to-luminance (B/L) ratios based on the CIE 1924 V (λ) for 195 test stimuli equally sampled from the whole area of the CIE1976(u′, v′) chromaticity diagram were measured for four color normal observers. The results of two observers were similar to results in previous studies in that the B/L ratio increases as purity of the stimulus increases. However, the results of the other two observers showed very low B/L ratios, especially in the reddish region. The B/L ratios based on each observer's sensation luminance were also calculated. Although the contour lines of equal B/L ratio become less atypical for the latter two observers, they still showed low B/L values compared to typical results. Large individual differences of the B/L ratio in the whole area of the chromaticity diagram were indicated. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 274–287, 1998

Effect of Jasmonates and Related Compounds on Seed Germination of Orobanche minor Smith and Striga hermonthica (Del.) Benth.

Abstract: Jasmonates and related compounds were found to elicit the seed germination of the important root parasites, clover broomrape (Orobanche minor Smith) and witchweed [Striga hermonthica (Del.) Benth]. The stimulation of seed germination by the esters was more effective than by the corresponding free acids, and methyl jasmonate (MJA) was the most active stimulant among the compounds tested.

Micro-displacement Characteristics under Tangential Force

Abstract: In this paper, firstly the obtained analytical results are briefly summarised. Next some experimental results are shown developed using finished ceramic surfaces of ZrO{2} and Al{2}O{3} together with SiC. And comparison of obtained experimental results with theoretical analyses and approximate equations introduced in the preceding works was made. The main conclusions are as follows. (1) Little difference can be seen in appearance between the experimental and calculated displacement behaviours, although frictional force of SiC is higher compared with those of other two ceramics and the slope of the curve after macro-slip of SiC is greater than those of the others. (2) Experimental values of tangential stiffness r{g} at the start of increasing the tangential force lie between calculated values by the two contact models. (3) Experimental values of tangential displacement δ{cmax} at the start of macro-slip are larger than those calculated by the two contact models and this is more evident for ZrO{2}.