Nonrandom distribution of chum salmon stocks in the Bering Sea and the North Pacific Ocean estimated using mitochondrial DNA microarray

More than 1,000 age-identified chum salmon Oncorhynchus keta collected at 23 stations in the Bering Sea and the North Pacific Ocean in June to July 2003 were used to estimate their origin of stocks using a DNA microarray developed for analyzing the mitochondrial (mt)DNA haplotypes. The observed haplotype distribution was nearly the same as that reported previously for fish collected in September 2002 and 2003 in the present surveyed areas. A conditional maximum-likelihood method for estimation of stock compositions indicated that the Japanese stocks mainly distributed in north central Bering Sea, whereas the Russian stocks were mainly in western Bering Sea. The North American stocks were abundant in eastern Bering Sea and around the Aleutian Islands. Such an area-specific stock composition was not significantly different between mature and immature fish. Thus, the combined results of 2 years suggest that the distribution of chum salmon is nonrandom in the surveyed areas in summer and autumn, and that fish of the same origin migrate together to the same area irrespective of age.     

Field trap test for bioassay of synthetic (1<Emphasis Type="Italic">S</Emphasis>,4<Emphasis Type="Italic">R</Emphasis>)-4-isopropyl-1-methyl-2-cyclohexen-1-ol as an aggregation pheromone of <Emphasis Type="Italic">Platypus quercivorus</Emphasis> (Coleoptera: Platipodidae)

An ambrosia beetle, Platypus quercivorus, is a vector of Japanese oak wilt, which causes massive mortality of oak trees in Japan. Previous studies have identified (1S,4R)-4-isopropyl-1-methyl-2-cyclohexen-1-ol ((−)-IMCH) as the major component of the aggregation pheromone of P. quercivorus. We tested the ability of synthetic (−)-IMCH to attract P. quercivorus adults. The synthetic compound attracted 14.4 times as many P. quercivorus, of both sexes, as control traps. Control and (−)-IMCH-baited traps both captured 3.32 times as many males as females, probably because of the nature of Lindgren funnel traps and of male-biased emergence sex ratio early in the season of adult flights. (−)-IMCH was proved to be a major component of the aggregation pheromone of P. quercivorus.     

Structure of xylan from culms of bamboo grass (Sasa senanensis Rehd.)

Xylan prepared from culms of kumaizasa (Sasa senanensis Rehd.), a representative species of bamboo grass, was hydrolyzed with-xylanase ofStreptomyces olivaceoviridis E-86. Four arabinoxylo-oligosaccharides and two glucuronoxylo-oligosaccharides were isolated from the enzymatic hydrolysate of the xylan by chromatography on a charcoal column, a Dowex 1-x8 column, a Toyo-pearl HW-40S column, and a LiChrospher 100 NH₂ column and on preparative paper chromatography. The results of the structural analyses of the saccharides showed that the isolated oligosaccharides had the structures of 3²--l-arabinofuranosyl-xylobiose, 3²--l-arabinofuranosyl-xylotriose, 3²--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylobiose, 3³--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylotriose, 2³--4-O-methyl-d-glucuronosyl-xylotriose, and 2³--d-glucuronosyl-xylotriose. From the structural analysis of the oligosaccharides derived from the xylan, kumaizasa xylan was concluded to be a kind of arabinoglucuronoxylan having not only stubs of singlel-arabinose and singled-glucuronic acid but also stubs of disaccharide units such as-d-xylopyranosyl-(1 2)-l-arabinofuranose.     

Potassium behavior and clay mineral composition in the soil with low effectiveness of potassium application

ABSTRACT

Increasing exchangeable potassium (ExK) content in soil to an appropriate level is important to mitigate the transfer of radioactive cesium to crops. We focused on a buckwheat (Fagopyrum esculentum Moench) field with a low ExK content, despite the application of K, in Fukushima Prefecture, Japan (Field A), following the Tokyo Electric Power Company Fukushima Dai-ichi (No. 1) Nuclear Power Plant accident in March 2011. We examined the relationship between K concentration and clay mineral composition in the soil of Field A and compared the findings with another field in Fukushima Prefecture (Field B) to clarify whether K applied to the soil was leached or remaining fixed. Pot experiments showed that K concentration in water seepage from pots following irrigation was significantly lower in pots from Field A than in those from Field B. Soil ExK content after soybean cultivation was lower in soils of Field A than those of Field B. These results indicate that K applied to Field A was fixed in the soil. Analysis of clay mineral composition confirmed the distinctive vermiculitic nature of Field A soils. This clay mineralogy would be associated with the higher K fixation ability of Field A than Field B soils. This study demonstrated that K fixation in vermiculite was a factor preventing the increase in ExK content from K application to Field A.     

Production of patchouli mild mosaic virus resistant patchouli plants by genetic engineering of coat protein precursor gene

Patchouli (Pogostemon cablin (Blanco) Benth), an aromatic crop which yields an essential oil, is widely cultivated in South-east Asia. Patchouli mild mosaic virus (PaMMV) infects patchouli plants and causes decrease in leaf biomass and essential oil yield. Transgenic patchouli plants with PaMMV coat protein precursor (CP-P) gene have been produced by Agrobacterium-mediated transformation. PaMMV CP-P gene integration into the patchouli genome was confirmed by the PCR method and by Southern blot analysis. The transformants were estimated to contain one to three copy genes using Southern blot analysis. The transformant with three copy genes was tested for the resistance to PaMMV by artificially inoculating plants grown in an environmentally controlled cabinet, and this transformant was found to be highly resistant to PaMMV. The transgenic patchouli plant with PaMMV CP-P gene should provide valuable material for protecting against PaMMV.     

The role of primary germ tubes in the life cycle of Blumeria graminis: The primary germ tube is responsible for the suppression of resistance induction of a host plant cell

When the conidia of Blumeria graminis f. sp. hordei (Bgh) are inoculated on barley coleoptile cells they produce short germ tubes called primary germ tubes (PGTs) about 2 h after inoculation. We evaluated the positive role of a PGT in inducing accessibility of the host cell under the germ tube. When an appressorium (APP) penetrated the same cell on which a PGT was present, the ratio of haustorium formation (penetration efficiency) was significantly higher than when an APP penetrated the cell adjacent to the one on which a PGT was present. When an APP penetrated the cell laterally adjacent to the one on which a PGT was present we killed the cell under the PGT by puncturing it with a microneedle and then investigated the penetration efficiency of the cell adjacent to the dead cell. As a control we killed the cell longitudinally adjacent to the one on which a PGT was present and investigated the penetration efficiency of the laterally adjacent cell. The results showed that the penetration efficiency of the former was significantly lower than that of the latter. This suggests that some accessibility factor might transfer from a cell on which a PGT is present to a laterally adjacent cell. The existence of a conidium body but not a PGT was not effective for induced accessibility of the host cell. Moreover, when a Bgh germling was removed 6 h after inoculation and another germling was transferred to the same cell, the penetration efficiency was significantly higher than that of control. As a control, a Bgh germling was transferred to a cell on which no germling was present. These results suggest that the existence of PGT is effective for induced accessibility of a host cell when penetrated by Bgh. However, it is unclear whether or not a PGT secretes some substance(s) which suppresses the resistance induction of a host cell.     

Effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers

The purpose of the present paper was to investigate the effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers. Four crossbred beef steers walked on a treadmill during a 6 week exercise period (1.2 km/h, 1 h/day and 5 days/week). The changes in plasma glucose and insulin levels following glucose infusion were analyzed immediately prior to (bodyweight: 260.4 ± 24.2 kg) and after (295.7 ± 30.1 kg) the exercise period. The basal levels of plasma glucose (86.4 vs. 82.0 mg/dL, P = 0.040) and insulin (24.5 vs. 14.3 μU/mL, P = 0.016) were significantly lower after the exercise period. Further, the increase in the levels of plasma glucose (420.4 vs. 280.8 mg/dL, P < 0.001) and insulin (94.5 vs. 73.1 μU/mL, P = 0.028) following the glucose infusion decreased after the exercise period. The area under the curve of plasma glucose (108.8 vs. 62.9 mg/dL per min, P < 0.001) and insulin (53.6 vs. 29.7 μU/mL per min, P = 0.018) indicated more rapid clearance of exogenous glucose and less insulin secretion for glucose clearance after the exercise period. These results suggest that regular exercise improves glucose tolerance, with lower insulin response to glucose infusion in growing steers, as observed in rodents and humans.     

Effect of temperature and cell density on ethanol fermentation by a thermotolerant aquatic yeast strain isolated from a hot spring environment

ABSTRACT: A thermotolerant, fermentative yeast strain named RND13 from a hot spring drainage was evaluated for its ethanol-producing ability at elevated temperatures at a high substrate concentration [15% (w/v) glucose] close to the level reflecting industrial practice. The RND13 was capable of utilizing glucose almost completely at 40°C with increasing inoculum size, producing ethanol up to 6.6% (w/v), which is comparable to levels (7.0–7.2%) at 30°C. The maximum rate of ethanol production by the RND13 was found to be 9.0 g/L per h at 40°C in an inoculum sized 5% (w/v). At 43°C, however, the RND13 could not utilize glucose to completion and showed a slight drop in the extent of produced ethanol [6.0% (w/v)]. Thus, the culture at 40°C with a 5% cell inoculum was considered to be the optimal condition for ethanol production at higher temperatures in terms of batch fermentation. In the phylogenetic analysis based on the small-subunit rDNA sequence, the strain was grouped together with both Candida glabrata and Kluyveromyces delphensis , which are relatively close to Saccharomyces cerevisiae .