Evaluation of drag coefficients of poplar-tree crowns by a field test method

To estimate the wind force that causes windthrow damage to a tree, the drag coefficients of actual-sized trees were evaluated by a field test method. In this method, wind velocity and stem deflection were monitored simultaneously. The wind force acting on a tree crown was calculated from stem deflection; stem stiffness was evaluated by conducting tree-bending tests. The results of tests conducted on three poplar trees showed that drag coefficient decreased with an increase in wind velocity. Although the variation in the drag coefficient was large at low wind velocity because of the vibrating behavior of the stem subjected to variable wind force, the variation at wind velocities above 10 m/s was small. The average drag coefficient at a wind velocity of 30 m/s was estimated by the curve-fitting of a power function to the wind velocity-drag coefficient relationship to be 0.102, which was smaller than that of actual-sized conifers studied in previous wind tunnel experiments. The drag coefficients of these crown areas in the defoliation season were smaller than those measured in the leafy season.     

Cryptosporidium avian genotype III as a possible causative agent of chronic vomiting in peach-faced lovebirds (Agapornis roseicollis)

In the present study, Cryptosporidium oocysts were found, by light microscopy, in 37 fecal samples of peach-faced lovebirds (Agapornis roseicollis). Cryptosporidium avian genotype III was isolated in 13 of the 37 infected birds by sequence analysis of the small subunit ribosomal RNA and the actin genes. All of the birds showed chronic vomiting and weight loss with enlargement of isthmi, narrowed proventricular lumens, and thickened proventricular walls radiographically. Cryptosporidium parasites were found only in the ductal epithelium of the proventricular glands in three of the tissue samples provided for necropsy. To date, there have been no reports concerning the pathogenicity, nor the location, of avian genotype III in avian hosts. Our report confirms, for the first time, the presence of avian genotype III in peach-faced lovebirds in Japan and also reveals the location in the avian host.     

Interaction between myostatin and extracellular matrix components

Myostatin, a member of the TGF-β superfamily, is a negative regulator of skeletal muscle mass. We have recently demonstrated that decorin binds to myostatin in vitro , and that immobilized decorin within the collagen matrix prevents myostatin-mediated inhibition of myoblast proliferation. However, little is known about other ECM molecules that bind to myostatin and modulate its activity. Thus, in the present study, we investigated the interaction of several other ECM molecules with myostatin. We here show that fibromodulin, fibronectin and laminin bind to myostatin in the presence of Zn²⁺ with a dissociation constant ( K_D ) of 10⁻¹⁰∼10⁻⁸ mol/L. Fibromodulin shows the highest affinity for myostatin among them. These results suggest that these ECM molecules may modulate myostatin activity like decorin does.     

Cytotoxicity of benzyl isothiocyanate in normal renal proximal tubular cells and its modulation by glutathione

In the present study, we examined the toxicity of benzyl ITC (BITC) and its urinary mercapturic acid metabolite (BITC-NAC), using a normal renal proximal tubular cell line, pig LLC-PK1. BITC increased cell death with an IC(50) value of about 7 μM, whereas the cytotoxic effect of BITC-NAC was five times weaker than that of BITC. We observed a significant necrosis of the compounds on LLC-PK1 cells with oxidative stress. In the presence of 5 mM glutathione (GSH), comparable to physiological levels, the cytotoxicity of BITC-NAC as well as BITC was significantly reduced. Furthermore, the increase in intracellular GSH levels by pretreatment with NAC before the BITC treatment resulted in inhibition of the BITC-induced necrotic events as well as intracellular oxidative stress. These results suggest that GSH is a determinant of cellular resistance against the BITC-mediated and oxidative stress-dependent cytotoxicity in renal proximal tubular cells.     

Identification of bitterness-masking compounds from cheese

Bitterness-masking compounds were identified in a natural white mold cheese. The oily fraction of the cheese was extracted and further fractionated by using silica gel column chromatography. The four fractions obtained were characterized by thin-layer chromatography and nuclear magnetic resonance spectroscopy. The fatty acid-containing fraction was found to have the highest bitterness-masking activity against quinine hydrochloride. Bitterness-masking activity was quantitated using a method based on subjective equivalents. At 0.5 mM, the fatty acid mixture, which had a composition similar to that of cheese, suppressed the bitterness of 0.008% quinine hydrochloride to be equivalent to that of 0.0049-0.0060% and 0.5 mM oleic acid to that of 0.0032-0.0038% solution. The binding potential between oleic acid and the bitter compounds was estimated by isothermal titration calorimetry. These results suggest that oleic acid masked bitterness by forming a complex with the bitter compounds.     

Cryopreservation of canine spermatozoa using a skim milk-based extender and a short equilibration time

Although useful spermatozoa cryopreservation techniques have been established, long-term equilibration seems to be required before freezing the spermatozoa of many species, including dogs. The fertility of cryopreserved dog spermatozoa from five males for a reduced equilibration period (0, 30, 60, 120 and 180 min) in a skim milk (SM)-based extender containing raffinose was evaluated in the present study. When the sperm was diluted with the extender at room temperature (RT) and cryopreserved without equilibration, the proportion of total motile spermatozoa (TMS) after thawing was lower (27%) than when the sperm was equilibrated for 30 min (33%), 60 min (32%), 120 min (44%; p < .05) or 180 min (29%). The proportion of TMS increased as the equilibration time increased and peaked at 120 min. Acrosome integrity was significantly lower in the cryopreserved spermatozoa that had not undergone the initial equilibration than in the equilibrated spermatozoa (p < .05). The normal rate of acrosomes increased with the extension of the first equilibration and peaked at 120 min. When frozen–thawed spermatozoa that had been diluted at RT and subjected to an initial equilibration lasting 60 or 180 min were transcervically inseminated into recipients, there were no differences in the delivery rate, litter size or breeding efficiency. In the cryopreservation of canine spermatozoa using a SM-based extender, even if the initial equilibration time was shortened to 60 min, the results were comparable to those obtained when the conventional method (with an initial equilibration time of 180 min) was used.     

Arsenic accumulation and speciation in Japanese paddy rice cultivars

We examined arsenic (As) accumulation and speciation in the major cultivars currently grown in Japan, because differences in grain As levels among cultivars may influence dietary As exposure in Japanese people. Ten major cultivars (Oryza sativa L.) were grown under flooded conditions in a paddy field with a background level of As (low-As soil) or in pots filled with soil containing a high level of As (high-As soil). In the low-As soil, the total grain As ranged from 0.11 to 0.17?mg?kg^?1, with a mean concentration of 0.14?mg?kg^?1, and inorganic As was the major species in all cultivars. There were few genotypic differences in the levels of either total As or inorganic As in the grain. In the high-As soil, total grain As increased to a mean level of 2.4?mg?kg^?1 in the 10 cultivars, with markedly increased levels of dimethylarsinic acid. The genotypic variations among cultivars in the levels of both total As and dimethylarsinic acid were statistically significant. However, the genotypic variability of inorganic As levels was quite small, and these levels remained low (at about 0.2?mg?kg^?1) even when total As levels increased markedly. These results suggest that differences in grain As levels among Japanese cultivars may not influence dietary As exposure, because there is little genotypic difference in the accumulation of inorganic As, which is considered more toxic than organic As to humans. We discuss the possible mechanism of As accumulation in Japanese paddy rice, in the context of the accumulation of As species in the developing grain and in other plant tissues.     

Changes in radiocesium concentration in a blueberry (Vaccinium virgatum Aiton) orchard resulting from radioactive fallout

We investigated changes in the radiocesium concentration in a blueberry (Vaccinium virgatum Aiton) orchard in Fukushima prefecture to clarify the radiocesium contamination for 3 years after the Tokyo Electric Power Company’s Fukushima Daiichi nuclear power plant accident occurred in mid-March 2011. In the aboveground part of blueberry bushes, the concentrations of radiocesium in branches that were directly affected by radioactive fallout were the highest among the samples investigated, and the concentrations in fruits were the lowest. The concentration of radiocesium decreased exponentially in the fruits and leaves over 3 years. The radiocesium concentrations in soils were higher in the surface layer. The amount of radiocesium in organic matter on the soil surface under the canopy greatly decreased from 2011 to 2012. The transfer factor of the radiocesium from soil to blueberry fruits decreased annually. These results suggest that radiocesium adhered directly to the aboveground organs of blueberry bushes in March 2011, and it is possible that the accumulation of radiocesium in fruits is mainly due to radiocesium transfer from the branches and trunk to fruits for several years after the nuclear power plant accident.     

Crystalline clay minerals of the soils derived from recent volcanic ashes in Hokkaido,Japan

For the past ten years much work has been carried out on clay minerals of volcanic ash soils. Most investigators have reported that allophane is dominant among clay minerals of volcanic ash soils and crystallizes to halloysite or meta-halloysite with the advance of weathering (1–8). On the other hand, UCHIYAMA, MASUI and ONIKURA (1960) found that montmorillonite predominates in the clay fraction of volcanic ash soil in Kawatabi (9). Furthermore, MASUI, SHOJI and UCHIYAMA (1966) showed that the major crystalline clay minerals of volcanic ash soils in the Tohoku district are montmorillonite, vermiculite, intergradient montmorillonite-vermiculite and chlorite (10). They also showed that these minerals increase with the advance of weathering and that kaolin minerals are minor constituents.