Topographical differences in soil N transformation using15N dilution method along a slope in a conifer plantation forest in Japan

Soil N transformation was investigated using¹⁵N dilution method along a slope on a conifer plantation forest. Although there was no significant difference in the net N mineralization rates by laboratory incubation, net nitrification rates increased downslope. Gross N transformation by¹⁵N dilution method showed a distinct difference not only on the rates, but also on the main process between the lower and the upper of the slope. Half of minelarized N was immobilized and the other half was left in NH ₄ ⁺ pool at the upper part of the slope, while all of mineralized N was used for immobilization or nitrification and NH ₄ ⁺ pool decreased at the lower of the slope. Soil N transformations were classified into two groups: one was shown below 773 m and the other was shown above 782 m. The incubation with nitrification inhibitor showed that nitrification was mainly conducted by autotrophs irrespective of the position of the slope. Microbial biomass and microbial C/N were similar among the sites. However, the gross mineralization rate was higher below 773 m than above 782 m under similar respiration rates. This suggests that the substrate quality may be one of the controlling factors for soil N transformation. Extractable organic C/N was similar to microbial C/N at the lower of the slope. It indicated that the substrate was more decomposable below 773 m. It is considered that soil N transformation is affected by topographical gradient of moisture and nutrient which makes plant growth and decomposition rate different.     

Low nitrogen availability and shallow plow layer decrease sugarcane (Saccharum officinarum L.) productivity in Kitadaito Island,Japan

Sugarcane is the main crop in Kitadaito Island, Okinawa, Japan. The average yield in Kitadaito Island for the past 30 years (1985–2015) was 44 Mg ha^?1, 31% lower than that (64 Mg ha^?1) in Okinawa Prefecture. Among the reasons for the low sugarcane productivity in Kitadaito Island, the effects of soil and cultivation factors have not been sufficiently studied. The objectives of this study were i) to evaluate the effects of soil physical and chemical properties and cultivation factors on sugarcane yield and sugar content in 50 fields of Kitadaito Island, and ii) to clarify factors affecting the sugarcane yield and sugar content. Statistical analysis of classification and regression trees (CART) showed that the sugarcane yield was low in fields with low available nitrogen (less than 16.5 mg kg^?1) and with shallow plow layer depth (less than 29 cm). The soil available nitrogen had a significant positive correlation with soil humus (r = 0.39, P < 0.05). Two-times of subsoiling in the field before planting and during growing periods resulted in the significant increase of the depth of plow layer, compared to the fields with single and no subsoiling. A high sugar content was obtained in fields with exchangeable Mg more than 3.8 cmol_c kg^?1 and pH(H₂O) less than 7.2. Our study therefore concluded that soil management practices for sugarcane production in Kitadaito Island should primarily be focused on available nitrogen, plow layer depth, and soil exchangeable Mg and pH.     

Extraction of Wheat Starch with Aqueous Sodium Hydroxide

Wheat starch was extracted with aqueous sodium hydroxide at 30–38% starch solids, pH 11.5–12.3, and 25–42°C for 0.17–24 hr. Stirring wheat starch at pH 12.3 and 25°C for 3 and 24 hr, then washing with water, neutralizing, and washing again, removed 70 and 90% phosphorus (P), respectively. Adding 16% sodium sulfate (dry starch basis) into the alkaline medium removed ≈80% of P at pH 12.0 and 25°C in 3 hr and >95% of P at pH 11.7 and 42°C in 3 hr. Sulfate ion was absorbed strongly by wheat starch in aqueous sodium hydroxide at pH 12.0, and sodium sulfate also increased the starch's uptake of hydroxide ion. Low-P wheat starch (>90% of P removed) retained the fatty acids in the untreated starch, but a fatty acid-amylose complex was not detectable by differential scanning colorimetry. The enthalpy of gelatinization of the low-P wheat starch almost matched that of prime starch, as did its X-ray diffraction pattern. Those data are consistent with saponification of the lysophospholipid in the amorphous phase of the starch to form fatty acid salts and glycerol-choline or glycerol-ethanolamine phosphodiesters that slowly diffused out of the granules. The low-P wheat starch was judged to have less “cereal” odor than the prime starch, and its pasting temperature at 9.3% starch solids was lowered by ≈10°C.     

Inorganic and organic osmolytes accumulation in five halophytes growing in saline habitats around the Aiding Lake area in Turpan Basin,Northwest China

Halophytes dominate the plant community in saline soils. Here, osmoregulation via the accumulation of osmolytes is the basic strategy by which plants survive salinity stress. We investigated the accumulation of inorganic and organic osmolytes in the leaves of five halophytes (Tamarix hispida, Halocnemum strobilaceum, Kalidium foliatum, Karelinia caspica, and Phragmites australis) growing in the dry lakebed of Aiding Lake, Xinjiang, China. The succulent euhalophytes (H. strobilaceum and K. foliatum) accumulated large amounts of Na⁺, whereas other species had low Na⁺ concentrations. P. australis contained high concentrations of soluble carbohydrates, mainly sucrose, and amino acids, such as proline and alanine. K. caspica accumulated large quantities of mannitol. H. strobilaceum and K. foliatum had high glycine betaine contents. Only T. hispida accumulated γ-butyro betaine, which was found in high concentrations. Our findings indicate that at least four types of osmolytes (carbohydrates, polyols, amino acids, and betaines) function either alone, or in combination in the osmoregulation of these halophytes.     

Analysis of the mineral composition of taro for determination of geographic origin

The mineral composition of taro ( Colocasia esculenta (L.) Schott) was analyzed to develop a method to distinguish taro produced in Japan and China. The concentrations of 15 elements (Al, Ca, Cl, Mg, Mn, Br, Co, Cr, Cs, Fe, K, Na, Rb, Sc, Zn) were assayed using instrumental neutron activation analysis. The concentrations of NO(3)(-), SO(4)(2-), H(2)PO(4)(-), Cl(-), malate, and oxalate were measured by ion chromatography. The mean concentrations of H(2)PO(4)(-), Co, Cr, and Na significantly differed (P < 0.01) between taro grown in Japan and that grown in China. Discriminant analysis was performed to identify the most efficient combination of elements and compounds to discriminate the taro geographic origin. The highest percentage of correct classification was achieved with a two-variable model including H(2)PO(4)(-) and Co (100% for Japanese, 93.75% for Chinese). Principal component analysis and cluster analysis using all of the assayed elements and compounds were also conducted to determine which elements significantly accounted for the variation of the taro mineral composition. We report on the potential of H(2)PO(4)(-) and Co concentrations to differentiate taro grown in China and Japan and discuss the sources of variability in the taro mineral composition of our samples.     

Serological survey of antibodies to four pathogens in wild boars in Nagano Prefecture,Japan

Wild boars (Sus scrofa) captured or found dead in Nagano Prefecture were surveyed for antibodies to Aujeszky’s disease virus (ADV), Erysipelothrix rhusiopathiae, porcine reproductive and respiratory syndrome virus (PRRSV), and Toxoplasma gondii. While all 168 samples tested were negative for anti-ADV antibodies and all 140 samples tested were negative for anti-PRRSV antibodies, all 190 samples tested were positive for anti-E. rhusiopathiae antibodies and 12 of 180 samples were positive for anti-toxoplasma antibodies. These results suggest that since E. rhusiopathiae and T. gondii cause zoonotic diseases, in addition to wild boars being a potential source of infection for domestic pigs, caution should be taken when handling wild boars or eating wild boar meat because of the possibility of human infection.     

Evidence of nighttime movement of finless porpoises through Kanmon Strait monitored using a stationary acoustic recording device

From March 2005 to March 2006, the presence of the finless porpoise Neophocaena phocaenoides in the Kanmon Strait, Japan was monitored using a stationary acoustic event recording device. A stereo acoustic event recorder (A-tag) recorded biosonar signals as well as sound source directions, which can be used to count the number of echolocating porpoises within a distance of 126m. During 75 days of effective observation, 37 porpoises were detected acoustically. On average, one individual was detected every two days. Most of the finless porpoises appeared at night, and no porpoises were observed from 12:00 to 18:00 hours. Shipping traffic observed using the same acoustic system showed trends opposite to that of finless porpoise during the daytime. The tidal current did not affect the presence of the animals. (up to 5.2 knots). However, porpoises were suggested to swim along the current direction. Finless porpoise appeared to be isolated and used relatively long-range sonar during the observations, suggesting that the porpoises passed through the Kanmon Strait rather than searched for prey.     

Thermally induced gelation of paramyosin from scallop adductor muscle

ABSTRACT:   Thermally induced gelation of paramyosin from scallop smooth adductor muscle was investigated by dynamic rheological measurements under various conditions. The paramyosin thermal gel was produced at pH 6.5 and 7.2 at temperatures above 30°C through a two-step increase in storage (G') and loss (G') moduli; these values were higher than in gels produced from actomyosin at a high temperature. The thermal gel properties were very firm and brittle. In contrast, one main peak of G' was observed during gelation at pH 8.0. The gel produced at pH 8.0 was more transparent and less soluble in a 6 M urea−0.5 M NaCl solution than those formed either at pH 6.5 or 7.2. These differences in the thermal gel properties are presumed to derive from the pH dependence of the gel matrix-forming process, such as oxidative cross-linking between cysteine residues, rather than from the thermal unfolding of the paramyosin molecules. The thermal gelation profile of chymotrypsin-digested paramyosin showed marked depression of G' at high temperature.