Ratio of rice reflectance for estimating leaf blast severity with a multispectral radiometer

 Rice reflectance was measured to determine the spectral regions most sensitive to leaf blast infection with a multispectral radiometer. As disease severity increased, reflectance also increased in the 400–500 nm (blue), 570–700 nm (red), and 900–2000 nm regions but decreased in the 500–570 nm and 700–900 nm regions. The increased reflectance in the blue and red regions may be attributed to decreased chlorophyll and carotenoid contents in response to the blast infection. The maximum and minimum reflectance differences occurred at 680 nm and 760 nm for the nondiseased and diseased rice, respectively. The spectral location of maximum sensitivity was 675 nm regardless of disease severity. Rice reflectance ratios were evaluated as indicators of leaf blast severity. Two ratios, R550/R675 (reflectance at 550 nm divided by reflectance at 675 nm), and R570/R675 quantified the significant disease severity. These wavelengths were selected based on the sensitivity minima and maxima. The ratios of nondiseased rice plants varied depending on growth stage. The variation in ratios must be considered when they are used to estimate leaf blast severity. Received: April 2, 2002 / Accepted: August 12, 2002     

Interspecies nuclear transfer embryos reconstructed from cat somatic cells and bovine ooplasm

This study was conducted to investigate the developmental capacity of domestic cat-bovine reconstructed embryos via interspecies somatic cell nuclear transfer (iSCNT) and to observe the mitochondrial DNA (mtDNA) content of the iSCNT embryos. The iSCNT embryos were generated using mixed-breed domestic cat fibroblasts as donor cells and enucleated bovine oocytes as the recipient cytoplasm. When the developmental capacities of iSCNT embryos and parthenogenic bovine embryos were compared, there was no difference (P>0.05) in the rates of cleavage and development to the 8-cell stage (86.6 vs. 84.0% and 32.2 vs. 36.2%, respectively). However, in contrast to development of parthenogenic embryos to the morula and blastocyst stages, no iSCNT embryos (0/202) developed beyond the 8-cell stage. For mtDNA analysis, iSCNT embryos at the 1-cell, 2-cell, 4-cell and 8-cell stages were randomly selected. Both cat and bovine mtDNA quantification analysis were performed using quantitative PCR. The levels of both cat and bovine mtDNA in cat-bovine iSCNT embryos varied at each stage of development. The cat mtDNA concentration in the iSCNT embryos was stable from the 1-cell to 8-cell stages. The bovine mtDNA in the iSCNT embryos at the 8-cell stage was significantly lower than that at the 4-cell stage (P<0.05). No difference in the proportions of cat mtDNA in the iSCNT embryos was found in any of the observed developmental stages (1- through 8-cell stages). In conclusion, bovine cytoplasm supports domestic cat nucleus development through the 8-cell stage. The mtDNA genotype of domestic cat-bovine iSCNT embryos illustrates persistence of heteroplasmy, and the reduction in mtDNA content might reflect a developmental block at the 8-cell stage.     

Potential application of simple easy-to-use insertion-deletion (InDel) markers in citrus cultivar identification

We previously developed insertion-deletion (InDel) markers that distinguish three genotypes (two homozygous and one heterozygous) of diverse citrus cultivars. These InDel markers were codominant and could be clearly detected by using simple agarose gel electrophoresis. We sought to establish a method for cultivar identification using these 28 InDel markers to genotype 31 citrus cultivars. The results revealed that a minimum of 6 markers were required to identify individuals using the three-genotype classification method. Furthermore, we found that a simple method for distinguishing between two genotypes (homozygous and heterozygous) could be used to identify individuals using a minimum of 7 markers. Our findings provide a basis for the development of simple and rapid citrus cultivar identification methods.     

Dehydroeffusol Rescues Amyloid β25–35-Induced Spatial Working Memory Deficit

Plant Foods for Human Nutrition - Amyloid β (Aβ) peptides produced from the amyloid precursor protein, a transmembrane protein, are neurotoxic and blocking the neurotoxicity may lead to...     

Corrosive-wear characteristics of diamond-coated cemented carbide tools

Continuous milling tests with diamond-coated and uncoated cemented carbide tools and polycrystalline diamond tools were carried out on air-dried and wet melapi (Shorea sp.) and western redcedar (Thuja plicata D. Don). These tools were examined for corrosive-wear characteristics of the tool-edge appearance, cutting-edge profile, edge recession, and cutting-power consumption. The tool surfaces were observed with a scanning electron microscope and were analyzed by energy-dispersive X-ray spectroscopy. Based on these examinations, the occurrence of corrosive wear while cutting wet woods was confirmed for the uncoated and polycrystalline diamond tools. In contrast, the coated tools did not exhibit corrosive wear, nor did delamitation or wear of the diamond film occur with any of the work materials. The diamond-coated tools showed high resistance not only to mechanical wear but also to corrosive wear.The results of this work were presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

柔嫩艾美耳球虫感染对鸡肠炎沙门氏菌感染复发的影响

本研究揭示了柔嫩艾美耳球虫感染可以引起鸡肠炎沙门氏菌感染的复发。复发的主要表现为盲肠内容物的肠炎沙门氏菌阳性率和数量再次显著地升高;肠炎沙门氏菌在盲肠中的滞留时间显著延长。这种复发与肠炎沙门氏菌的初始感染量及球虫感染时间有关。肝脏和脾脏阳性率无显著变化。     

Ventilation of seawater during bleeding suppresses the occurrence of burnt meat in yellowtail <Emphasis Type="Italic">Seriola quinqueradiata</Emphasis>

Fifteen farmed yellowtail Seriola quinqueradiata were randomly selected from sea cages. Five fish were slaughtered instantly by cutting the spinal bulb (control group). The remaining ten fish were left for 20 min in a narrow net and then they were slaughtered by cutting the spinal bulb instantly. These ten fish were bled in two water tanks. In one tank, the water was aerated (ventilation group), while the other tank was not aerated (burnt group). The ATP ratio in the control group (83.8 ± 4.1%) was higher than the ventilation group (37.2 ± 22.1%) and the burnt group (5.8 ± 6.0%) at 3 h after slaughter. The K value of the burnt group increased remarkably at 3 h after slaughter, and was significantly higher than those for the other groups. The ventilation group showed a recovery in available energy for physiological maintenance to the same level as the control group during bleeding, as well as a significantly slowed loss of muscular firmness compared to the burnt group. This study shows that the yellowtail continued to respire and take up oxygen until complete physiological death, and elevated oxygen levels during bleeding slowed the postmortem changes and suppressed the occurrence of burnt meat.     

Assemblages of vertical migratory mesopelagic fish in the transitional region of the western North Pacific

Assemblages of vertical migratory mesopelagic fish are described for the nighttime upper 20 m layer of the transitional and adjacent waters in the western North Pacific. Twenty-three mesopelagic fish species belonging to six families and 16 genera were collected during June 1996. Family Myctophidae was most speciose, represented by 17 species, followed by Sternoptychidae (two spp.) and Bathylagidae (one spp.). Six assemblages are recognized based on their species composition: Subarctic, Northern Transition, Southern Transition, Subtropical, Slope Water and Seamount Assemblages. These assemblages are also characterized by size composition and biomass of the catches. The distributions of the Subarctic, Northern Transition, Southern Transition and Subtropical Assemblages are approximately defined by the Kuroshio and Oyashio fronts and the Subarctic Boundary. Slope Water and Seamount Assemblages are closely related to the slope water around the shelf edge off Japan and waters around the Shatsky Rise and the Emperor Seamount chain, respectively. The importance of the Southern Transition Assemblage area between the Kuroshio front and Subarctic Boundary as spawning and nursery grounds of many subarctic, transitional and subtropical fishes is elucidated, based on the geographical distribution patterns of their larvae and juveniles.     

Variations in the proximate composition of muscle in cultured yellowtail Seriola quinqueradiata at different anatomical portions

In this study, we examined differences in the proximate composition of five major muscles of the yellowtail, as well as the relation between seasonal variations in the levels of crude lipids and texture of these muscles. The differences in content among these muscles and the variations in each muscle were greater for crude lipid and moisture content than for crude protein content. The crude lipid content of Musculus latero-dorsalis correlated with that of M. carinatus dorsalis, M. latero-ventralis, M. carinatus ventralis, and red muscle. In M. latero-dorsalis, the crude lipid content started to increase in October, remained high from November to January, started to decrease in March, and was low from April to June. The firmness of M. latero-dorsalis increased from October to November and started to decrease in March. Firmness decreased concurrently with decreases in crude lipid content and increased concurrently with increases in crude lipid content. The results of this study suggest that it is possible to predict the proximate compositions of other yellowtail muscles from the proximate composition of M. latero-dorsalis. Seasonal variation in crude lipid content of the M. latero-dorsalis was found, and variations in crude lipid tended to parallel those in firmness.     

Effects of alcohol extract of defatted soybean meal on growth performance and digestive physiology of yellowtail <Emphasis Type="Italic">Seriola quinqueradiata</Emphasis>

The effects of alcohol extract of soybean meal on growth performance, digestibility, and pancreatic enzyme and bile acid status of yellowtail Seriola quinqueradiata were studied. Fish were fed one of the following for 8 weeks: a fish meal (FM) control diet (FMD), a defatted soybean meal diet (SBMD), an alcohol-extracted SBM diet (ExSBMD), an ExSBMD with alcohol-extract diet (ExSBM + ExtD), and an FMD with alcohol-extract diet (FM + ExtD). Growth performance was significantly inferior in fish fed with SBM, ExSBM + ExtD, and FM + ExtD compared to FMD- or ExSBMD-fed fish. Total bile acid levels, and trypsin and lipase activities in the anterior intestine were significantly lower in fish fed with SBM, ExSBM + ExtD, and FM + ExtD than in fish fed with ExSBMD and FMD, despite similar values in gallbladder or pyloric caeca. Cholecystokinin mRNA levels of the former diet-fed fish were significantly lower than those of FMD- or ExSBMD-fed fish. Lipid and protein digestibility of fish fed with SBMD, ExSBM + ExtD, and FM + ExtD was significantly reduced in comparison with that of fish fed with FMD or ExSBMD. These findings indicate that the alcohol extract of soybean meal inhibited the secretion of bile acids and pancreatic enzymes by a decrease of cholecystokinin stimulation. This inhibition seemed to be responsible for a low growth performance through impairment of the assimilation of lipid and protein.