Characterization of the products resulting from ethylene glycol liquefaction of cellulose

The composition of liquefied cellulose in the presence of ethylene glycol (EG) was studied. The liquefied products were fractionated and analyzed with highperformance liquid chromatography and nuclear magnetic resonance. EG-glucosides were detected as the only saccharides and 2-hydroxyethyl levulinate as the highly decomposed compound derived from cellulose. Quantitative analysis of the EG-glucosides and levulinic acid that comes from the levulinate shows the presence of the following mechanism in the EG-liquefaction of cellulose. First, cellulose is degraded and produces considerable amounts of EG-glucosides during the early stage of liquefaction. Then, when liquefaction is prolonged, the glucosides are decomposed, leading to a large quantity of levulinates.     

Chemical analysis of the product in acid-catalyzed solvolysis of cellulose using polyethylene glycol and ethylene carbonate

Degradation and decomposition of cellulose were studied in an acid-catalyzed solvolysis treatment of biomass using polyethylene glycol (PEG) and ethylene carbonate (EC). The solvolysis reaction was followed by a typical reaction system of wood liquefaction that uses sulfuric acid catalyst at 140° or 150°C at atmospheric pressure. The methods of fractionation and chemical analysis of the degraded cellulose in the solvolyzed product are discussed. The solvolyzed product was separated into several fractions, and they were hydrolyzed to release glucose and levulinic acid to determine the quantity of glucosides and levulinates in the solvolysis product. The data clearly showed that the solvolysis reaction had the same mechanism when using PEG or EC. Degradation of cellulose leads to the formation of glucosides, which then decompose, resulting in a levulinic acid structure, and producing a water-insoluble fraction. The conversion rates of both glucosides and levulinates strongly depend on the reaction conditions of the solvolysis. In particular, EC promotes faster conversion of the reactions. The method discussed here is a chemical analytical technique for characterization of the products of wood liquefaction.     

A basic study of chemotaxis of leptospiras

Chemotaxis of leptospiras was studied using a U-tube made of a commercially available straw-shaped polypropylene tube with an uneven flexible part. The U-tube was made by folding the polypropylene tube double and binding the vertical parts by a piece of tape, thus making the uneven flexible part the bottom. Semi-solid Korthof's medium was poured into the U-tube. Preliminary experiments showed that the medium containing 0.5% agar and measuring 2 cm in in length was appropriate. Leptospiras inoculated on the top of the medium of one side of the U-tube moved toward the top of the medium of the other side. The leptospiral move toward the uninoculated top was significantly faster when 6 micrograms of hemoglobin were added to the uninoculated top. Chemotaxis of leptospiras to hemoglobin was thus shown, which is the first evidence of chemotaxis of leptospiras.     

Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon

The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt-rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.     

Yield and dry matter productivity of Japanese and US soybean cultivars

The difference in yields of cultivars may be causing difference in soybean yield between Japan and the USA. The objective of this study was to identify the effect of the cultivar on dry matter production and to reveal the key factors causing the differences in yield by focusing utilization of solar radiation in recent Japanese and US soybean cultivars. Field experiments were conducted during two seasons in Takatsuki, Japan (34°50′), and in a single season in Fayetteville (36°04′), AR, USA. Five Japanese and 10 US cultivars were observed under near-optimal conditions in order to achieve yields as close to their physiological potential as possible. The seed yield and total aboveground dry matter (TDM) were measured at maturity as long as radiation was intercepted by the canopy. The seed yield ranged from 3.10t ha^?1 to 5.91t ha^?1. Throughout the three environments, the seed yield of US cultivars was significantly higher than that of Japanese cultivars. The seed yield correlated with the TDM rather than the HI with correlation coefficients from .519 to .928 for the TDM vs. .175 to .800 for the HI, for each of the three environments. The higher TDM of US cultivars was caused by a higher radiation use efficiency rather than higher total intercepted radiation throughout the three environments. The seasonal change in the TDM observed in four cultivars indicated that dry matter productivity was different between cultivars, specifically during the seed-filling period.     

Response of the leaf photosynthetic rate to available nitrogen in erect panicle-type rice (Oryza sativa L.) cultivar,Shennong265

Increasing the yield of rice per unit area is important because of the demand from the growing human population in Asia. A group of varieties called erect panicle-type rice (EP) achieves very high yields under conditions of high nitrogen availability. Little is known, however, regarding the leaf photosynthetic capacity of EP, which may be one of the physiological causes of high yield. We analyzed the factors contributing to leaf photosynthetic rate (P_n) and leaf mesophyll anatomy of Nipponbare, Takanari, and Shennong265 (a EP type rice cultivar) varieties subjected to different nitrogen treatments. In the field experiment, P_n of Shennong265 was 33.8 μmol m^?2 s^?1 in the high-N treatment, and was higher than that of the other two cultivars because of its high leaf nitrogen content (LNC) and a large number of mesophyll cells between the small vascular bundles per unit length. In Takanari, the relatively high value of P_n (31.5 μmol m^?2 s^?1) was caused by the high stomatal conductance (g_s; .72 mol m^?2 s^?1) in the high-N treatment. In the pot experiment, the ratio of P_n/C_i to LNC, which may reflect mesophyll conductance (g_m), was 20–30% higher in Nipponbare than in Takanari or Shennong265 in the high N availability treatment. The photosynthetic performance of Shennong265 might be improved by introducing the greater ratio of P_n/C_i to LNC found in Nipponbare and greater stomatal conductance found in Takanari.     

Ceramide aminoethylphosphonate from jumbo flying squid Dosidicus gigas attenuates the toxicity of cyanotoxin microcystin-LR

We have previously established the method for isolation of ceramide aminoethylphosphonate (CAEP) from jumbo flying squid Dosidicus gigas. In this study, we performed a MTT assay to evaluate the safety of CAEP to the cell lines for the application to health food and supplements. The CAEP did not show any cytotoxicity to various HEK293-transfectant cells. Next, we elucidated the positive function of CAEP to the somatic cells. Recently, we have reported that hepatotoxin microcystin-LR was taken up into the hepatocytes mediated by hepatocellular uptake transporters OATP1B1 and OATP1B3, and the cells were induced cytotoxicity subsequently. Cytotoxicity of microcystin-LR to permanently OATP1B3-expressing HEK293-OATP1B3 cells rather than to HEK293-OATP1B1 cells was preferentially attenuated by CAEP in a concentration-dependent manner. In addition, the enzyme activity of serine/threonine phosphatase, which was inhibited by microcystin-LR, was recuperated by co-exposure to CAEP. Furthermore, microcystin-LR-induced cellular protein phosphorylation were disrupted by CAEP exposure. These results suggested that CAEP is a promising remedy and/or preventive medicine for liver damage with microcystin-LR.     

Identification of the strong vasorelaxing substance scirpusin B, a dimer of piceatannol, from passion fruit (Passiflora edulis) seeds

Piceatannol is present in passion fruit (Passiflora edulis) seeds in high amounts. In this study, we isolated the second major polyphenolic compound of passion fruit seeds and identified it as scirpusin B, which is a dimer of piceatannol. We investigated the antioxidant activities and vasorelaxing effects of these polyphenols. Their antioxidant effects were measured using an in vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and their vasorelaxant effects were determined ex vivo in rat thoracic aorta. Both polyphenolic compounds exhibited potent antioxidant activities and significant vasorelaxant effects in endothelium-intact aortas. More specifically, scirpusin B exerted a greater antioxidant activity and vasorelaxant effect compared with that of piceatannol. Additionally, the vasorelaxation effects of the compounds were induced via the NO derived from the endothelium. This study provides the possibility that polyphenols in passion fruit seeds are effective against cardiovascular diseases (CVDs).     

Studies on the nitrification in soil,with special reference to the population of nitrifier

A number of papers have been published on nitrification in soil. The problem of the nitrification has become increasingly important because of the appearance of new forms of nitrogenous fertilizers such as ammonium chloride or urea, etc.     

Predicting chronosequential changes in carbon stocks of pachymorph bamboo communities in slash-and-burn agricultural fallow,northern Lao People’s Democratic Republic

In northern Lao People’s Democratic Republic, rising human population has drastically reduced the fallow period of slash-and-burn agriculture which has led to a considerable decrease in the carbon stock in these communities. We estimated chronosequential changes in the communities' carbon stocks, and established the relationship between the fallow period and fallow-period-average carbon stocks in three carbon pools of bamboo-dominated communities in hilly areas of the Luang Prabang Province, northern Lao People’s Democratic Republic. Based on measurements by destructive sampling, we devised a model and root-to-shoot ratios for estimating bamboo biomass. In six secondary plant communities established after slash-and-burn cropping, we estimated community biomass using the above model and others, and measured deadwood and litter stocks. The communities’ biomass and deadwood significantly increased with time after the last cropping and the former reached about 100 Mg ha⁻¹ after 15 years, whereas litter stocks did not show significant trends over time. Extending the fallow period from 2 to 5 years would increase fallow-period-average carbon stock from 14.2 to 25.1 Mg C ha⁻¹. The overstory height was significantly correlated with biomass, deadwood, and litter carbon stocks of these communities. Based on our findings, changes in a community’s carbon stocks can be estimated using the changes in overstory height, which should be taken into account in future studies to reduce uncertainty in estimating carbon stocks in tropical ecosystems.