Diversity of glutelin acidic subunit polypeptides in rice cultivars collected from Northern Vietnam

The diversity of glutelin acidic polypeptides in rice cultivars collected from Northern Vietnam was characterized via sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS‐PAGE) and isoelectric focusing (IEF) electrophoresis. Glutelin acidic subunits were separated into four bands by molecular mass, as α‐1 (39 kDa), α‐2 (38 kDa), α‐3 (37.5 or 37 kDa) and α‐4 (34 or 33 kDa). One hundred and eighty‐five Vietnamese rice cultivars were divided into three types, based on differences in staining intensity and the molecular size of the α‐3 and α‐4 polypeptides derived from SDS‐PAGE analysis. Wide variation was also observed in the isoelectric point (pI) staining intensity, in addition to the absence/presence of pI bands detected via IEF analysis. A total of 16 pI bands, ranging from pI 6.30 to pI 7.52, were identified in the various local rice cultivars. The maximum and minimum of IEF bands detected were 14 and 10, respectively. The genetic variability index (H′) ranged from 0.280 to 0.820, which confirms that local rice cultivars from Northern Vietnam have diverse glutelin seed storage units.     

Comparison of the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye (T. obesus) tuna associated with drifting FADs in the equatorial central Pacific Ocean

We evaluated the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) associated with drifting fish aggregating devices (FADs) in the equatorial central Pacific Ocean. A total of 30 skipjack [34.5–65.0 cm in fork length (FL)], 43 yellowfin (31.6–93.5 cm FL) and 32 bigeye tuna (33.5–85.5 cm FL) were tagged with coded transmitters and released near two drifting FADs. At one of the two FADs, we successfully monitored the behavior of all three species simultaneously. Several individuals remained around the same FAD for 10 or more days. Occasional excursions from the FAD were observed for all three species, some of which occurred concurrently for multiple individuals. The detection rate was higher during the daytime than the nighttime for all the species, and the detection rate for bigeye tuna was higher than for yellowfin or skipjack tuna. The swimming depth was deeper during the daytime than nighttime for all species. The fish usually remained shallower than 100 m, but occasionally dived to around 150 m or deeper, most often for bigeye and yellowfin tuna during the daytime. The swimming depth for skipjack tuna was shallower than that for bigeye and yellowfin tuna, although the difference was not large, and is probably not sufficient to allow the selective harvest of skipjack and yellowfin tuna by the purse seine fishery. From the detection rate of the signals, bigeye tuna is considered to be more vulnerable to the FAD sets than yellowfin and skipjack tuna.     

Potential contributions of forestry and wood use to climate change mitigation in Japan

By considering trade-offs and complementarity between carbon removal from the atmosphere by forests and emission reduction by wood use, we developed a forest-sector carbon integrated model for Japan. We discuss mitigation measures for Japan based on model projections. The integrated model included the forest model and the wood use model. Based on three scenarios (baseline, moderate increase, and rapid increase) of harvesting and wood use, the integrated model projected mitigation effects including carbon removal by forests and emission reduction through the wider use of wood, until 2050. Results indicate that forests will not become a source of net carbon emissions under the three scenarios considered. The baseline scenario is most effective for mitigating climate change, for most periods. However, the sum total of carbon removal in forests and carbon emission reductions by wood use under the rapid increase scenario exceeded the one of the moderate increase scenario after 2043. This was because of strong mitigation activities: promoting replanting, using new high-yield varieties, and wood use. The results also indicated that increases in emission reduction due to greater wood use compensated for 67.9 % of the decrease of carbon removal in 2050, for the rapid increase scenario. The results show that carbon removal in forests is most important in the short term because of the relative youth of the planted forests in Japan, and that mitigation effects by material and energy substitution may become greater over the longer term.     

Species identification of imported and Japanese commercial green algal products based on phylogenetic analyses using the nrITS2 and 5S rDNA spacer regions

The identification of imported green algal products represents a critical challenge to the Japanese Customs Service in terms of ensuring effective control of imported quota items (species of genera Monostroma and Enteromorpha and their products). To assist officials in this difficult task, we tested the applicability of phylogenetic analyses using the nuclear-encoded ribosomal DNA internal transcribed spacer 2 (nrITS2) and 5S ribosomal DNA (rDNA) spacer regions to identify green algal products at the species level. Our nrITS2-based phylogenetic analysis was able to roughly separate the Ulva-related samples into three clades: the Ulva linza–procera–prolifera (LPP) complex and two other clades, and identified the Monostroma-related samples as M. nitidum. Subsequent detailed analysis within the LPP complex using the 5S rDNA spacer region divided the samples into two groupings (the U. linza clade and U. prolifera clade), while it detected possible hybrid samples of U. linza and U. prolifera from a number of commercial green algal products.     

Vertical behavior of juvenile yellowfin tuna Thunnus albacares in the southwestern part of Japan based on archival tagging

The behavior of juvenile yellowfin tuna Thunnus albacares in southwestern Japan was investigated using archival tag data from five fish (fork length 52.5–92 cm, days at liberty 26–280 days) released near the Nansei Islands (24–29°N, 122–130°E). Vertical behavior was classified into three patterns: “shallow” (≥50 % of daytime hours at depth of <50 m), “deep” (≥50 % of daytime hours at ≥100 m), and “intermediate” (other than “shallow” or “deep”). The pooled proportion of the number of days of each behavior was 29, 25 and 46 %, respectively. The proportion of “shallow” behavior increased with fish size. The proportion of time spent near the surface at nighttime increased in the colder season, when the thermal gradient was relatively small. Surface-oriented behavior (fish remained at a depth of <10 m for more than 10 min) occurred mainly during nighttime and between November and January. Dives exceeding 500 m were occasionally observed (0.02 day^?1), and one fish dived to 1230 m. The results of our study show that yellowfin tuna were typically distributed in the mixed layer or upper thermocline where the water temperature was close to the sea surface temperature and that the vertical behavior was variable.     

Development of acid soil conditioning agent from lignin by ozone treatment I

A purified softwood kraft lignin was modified by ozone treatment and its activity as an acid soil conditioning agent, mainly focusing on elimination of aluminum toxicity, was assayed by planting experiments. The growth of radish root was examined in nutrient solution containing CaCl₂ and AlCl₃ at pH 4.8 with and without modified kraft lignins. The modified kraft lignins that absorbed 1.8 and 3.9 moles of ozone per C6-C3 unit (M _w 180) showed two effects: the elimination of aluminum toxicity and the acceleration of root growth. The effect on the elimination of aluminum toxicity was observed even with modified kraft lignin that absorbed 1.0 mole of ozone per C6-C3 unit. The high molecular weight part of the modified kraft lignin that absorbed 3.9 moles of ozone per C6-C3 unit also proved to be effective not only in elimination of aluminum toxicity but also in acceleration of root growth. The acceleration effect of ozone-treated lignins on root growth was also observed under the absence of aluminum in planting experiments. This report was presented in part at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006     

Comparative Analysis of Rice Genome Sequence to Understand the Molecular Basis of Genome Evolution

Accurate sequencing of the rice genome has ignited a passion for elucidating mechanism for sequence diversity among rice varieties and species, both in protein-coding regions and in genomic regions that are important for chromosome functions. Here, we have shown examples of sequence diversity in genic and non-genic regions. Sequence analysis of chromosome ends has revealed that there is diversity in both sequences and distribution in the region of telomere repeat arrays, from chromosome to chromosome, within a plant. Detailed study has allowed us to speculate the mechanism of generation of these arrays. Sequence analysis using various cultivated and wild rice of the sd1 gene, which contributed to the “Green Revolution” in rice varieties and their wild progenitors, has also demonstrated sequence diversity, which is correlated with taxonomic classification. These results indicate that detailed analysis of sequence diversity and comparison might give us a clue in elucidating mechanism of the evolution of rice genome.     

Reliable enzyme-linked immunosorbent assay for the determination of soybean proteins in processed foods

Among allergenic foods, soybean is known as a food causing adverse reactions in allergenic patients. To clarify the validity of labeling, the specific and sensitive detection method for the analysis of the soybean protein would be necessary. The p34 protein, originally characterized to be p34 as an oil-body associated protein in soybean, has been identified as one of the major allergenic proteins and named Gly m Bd 30K. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of the soybean protein in processed foods was developed using polyclonal antibodies raised against p34 as a soybean marker protein and the specific extraction buffer for extract. The developed sandwich ELISA method was highly specific for the soybean protein. The limit of detection (LOD) and the limit of quantification (LOQ) of the developed ELISA were 0.47 ng/mL (equivalent to 0.19 microg/g in foods) and 0.94 ng/mL (equivalent to 0.38 microg/g in foods), respectively. The recovery ranged from 87.7 to 98.7%, whereas the intra- and interassay coefficients of variation were less than 4.2 and 7.5%, respectively. This study showed that the developed ELISA method is a specific, precise, and reliable tool for the quantitative analysis of the soybean protein in processed foods.     

Seasonal changes of nitrate concentrations in baseflow headwaters of coniferous forests in Japan: A significant indicator for N saturation

Understanding the seasonal and regional patterns of nitrogen (N) components in the headwaters of forested watersheds is important for forests management. Here, we investigated the NO₃-N concentration and its seasonal variations in the baseflow headwaters in Japanese coniferous forests with different N saturation status in five regions (i.e., Nagano, Tokyo, Aichi, Kochi and Mie). We found that the ratios of NO₃-N to DON were significantly higher in the N-saturated regions including Nagano (14.1 ± 2.2) and Tokyo (16.5 ± 4.1), compared with the regions, which didn't experience N saturation including Aichi (1.4 ± 0.2), Kochi (5.1 ± 1.8), and Mie (2.2 ± 0.5). In comparison with the regions without experiencing N saturation, the relatively higher NO₃-N concentration, as well as its contrastive variation between growing season and dormant season, was also characteristic of the seasonal NO₃-N concentration in the N-saturated regions. Our findings have indicated that NO₃-N concentration, its seasonal variations, and the ratio of NO₃-N to DON, are the better and applicable indicators for evaluating N saturation status in Japanese coniferous forests.