The spread of tissue necrosis leads to plant death. We isolated 18 lethal necrotic mutants induced in rice (Oryza sativa L.) by gamma-irradiation. The necrotic lethality among the 18 mutants was controlled by single r...The spread of tissue necrosis leads to plant death. We isolated 18 lethal necrotic mutants induced in rice (Oryza sativa L.) by gamma-irradiation. The necrotic lethality among the 18 mutants was controlled by single recessive genes designated necrotic lethality1 (nec1) to nec18. These mutants display pale-green leaves from the third-leaf stage and leaf-tip necrosis, which spreads to the whole plant, killing it. Genetic mapping and histochemical analysis of the lethal necrotic mutants were conducted. At least four independent loci on chromosomes 2 and 4 controlled necrotic lethality. Therefore, the genetic causes of lethal necrosis vary among mutant stocks. Histochemical analysis at 12 days after sowing showed that H2O2 accumulated in the necrotic parts of leaves, and that cell death occurred throughout the leaf. Mutants for early necrotic lethality (<24 days to lethality) were characterized by the rapid spread of H2O2 accumulation throughout the third leaf. Mutants for late necrotic lethality (>35 days to lethality) were characterized by the incomplete spread of H2O2 accumulation within the third leaf.展开更多
The green rice leafhopper (GRH;Nephotettix cincticeps Uhler) is one of the most devastating insect pests of cultivated rice (Oryza sativa L.) in temperate regions in Asia. Using the rice germplasms with biotic stress ...The green rice leafhopper (GRH;Nephotettix cincticeps Uhler) is one of the most devastating insect pests of cultivated rice (Oryza sativa L.) in temperate regions in Asia. Using the rice germplasms with biotic stress resistance is the most effective and environmentally-friendly way to control the insect pests in the paddy. Sixty accessions from a core set of worldwide collection of rice were characterized for resistance to the GRH by antibiosis test both at the seedling and at the booting stages. The positive correlations of average nymph mortality (ANM) were observed between at the seedling stage and at the booting stage on 3 days after infestation (DAI) (r = 0.684**), 5DAI (r = 0.680**), and 7DAI (r = 0.652**), respectively. This result will give us the opportunity to screen resistance to the GRH with the cost-efficient way using rice seedlings in a growth chamber. To classify the 60 accessions evaluated, the ANM of the GRH of each accession was compared to the respective ANM of resistant and susceptible controls with the least significant difference (LSD) value. Based on the statistical difference or similarity of the ANMs to the resistant and the susceptible controls, we proposed the four groups of resistance to the GRH, (I) high level of resistance, (II) considerable level of resistance, (III) moderate level of resistance, and (IV) susceptibility. At the seedling stage, a total of 26 accessions were highly resistant in addition to other 6 for considerable level of resistance and other 10 for moderate level of resistance. At the booting stage, on the other hand, a total of 18 accessions were highly resistant in addition to other 3 for considerable level of resistance and other 5 for moderate level of resistance. A total of 42 accessions with high to moderate level of resistance were distributed across 16 countries in Asia in addition to each one for Madagascar and USA. The classification of landraces based on the present protocol for screening resistance to the insect provided fundamental information for genetics and breeding on resistance to the GRH in rice.展开更多
We studied the effects of exercise on muscle mitochondria, and lipid and glycogen content in non-alcoholic steatohepatitis (NASH) model rats. Male Sprague-Dawley rats were randomly separated into 3 groups: the control...We studied the effects of exercise on muscle mitochondria, and lipid and glycogen content in non-alcoholic steatohepatitis (NASH) model rats. Male Sprague-Dawley rats were randomly separated into 3 groups: the control group was fed standard chow;the NASH group was fed a methionine-choline-deficient high-fat diet (MCD);the NASH-exercise group was fed the MCD and exercised three times a week. Exercise training consisted of continuous running for thirty minutes at a 13 m/min, 6° slope on a motor-driven rodent treadmill for 6 weeks. Mitochondria content in NASH group decreased in the both fiber types compared with those of the control group. As compared between the NASH and NASH-exercise groups, however, exercise not only promoted significant improvements in liver fibrosis and cirrhosis and triglyceride (TG) content but also increased mitochondria content in type I muscle fiber in particular. These data suggest that exercise improved hepatic steatosis in NASH model rats and can prevent the progression of NASH.展开更多
文摘The spread of tissue necrosis leads to plant death. We isolated 18 lethal necrotic mutants induced in rice (Oryza sativa L.) by gamma-irradiation. The necrotic lethality among the 18 mutants was controlled by single recessive genes designated necrotic lethality1 (nec1) to nec18. These mutants display pale-green leaves from the third-leaf stage and leaf-tip necrosis, which spreads to the whole plant, killing it. Genetic mapping and histochemical analysis of the lethal necrotic mutants were conducted. At least four independent loci on chromosomes 2 and 4 controlled necrotic lethality. Therefore, the genetic causes of lethal necrosis vary among mutant stocks. Histochemical analysis at 12 days after sowing showed that H2O2 accumulated in the necrotic parts of leaves, and that cell death occurred throughout the leaf. Mutants for early necrotic lethality (<24 days to lethality) were characterized by the rapid spread of H2O2 accumulation throughout the third leaf. Mutants for late necrotic lethality (>35 days to lethality) were characterized by the incomplete spread of H2O2 accumulation within the third leaf.
文摘The green rice leafhopper (GRH;Nephotettix cincticeps Uhler) is one of the most devastating insect pests of cultivated rice (Oryza sativa L.) in temperate regions in Asia. Using the rice germplasms with biotic stress resistance is the most effective and environmentally-friendly way to control the insect pests in the paddy. Sixty accessions from a core set of worldwide collection of rice were characterized for resistance to the GRH by antibiosis test both at the seedling and at the booting stages. The positive correlations of average nymph mortality (ANM) were observed between at the seedling stage and at the booting stage on 3 days after infestation (DAI) (r = 0.684**), 5DAI (r = 0.680**), and 7DAI (r = 0.652**), respectively. This result will give us the opportunity to screen resistance to the GRH with the cost-efficient way using rice seedlings in a growth chamber. To classify the 60 accessions evaluated, the ANM of the GRH of each accession was compared to the respective ANM of resistant and susceptible controls with the least significant difference (LSD) value. Based on the statistical difference or similarity of the ANMs to the resistant and the susceptible controls, we proposed the four groups of resistance to the GRH, (I) high level of resistance, (II) considerable level of resistance, (III) moderate level of resistance, and (IV) susceptibility. At the seedling stage, a total of 26 accessions were highly resistant in addition to other 6 for considerable level of resistance and other 10 for moderate level of resistance. At the booting stage, on the other hand, a total of 18 accessions were highly resistant in addition to other 3 for considerable level of resistance and other 5 for moderate level of resistance. A total of 42 accessions with high to moderate level of resistance were distributed across 16 countries in Asia in addition to each one for Madagascar and USA. The classification of landraces based on the present protocol for screening resistance to the insect provided fundamental information for genetics and breeding on resistance to the GRH in rice.
文摘We studied the effects of exercise on muscle mitochondria, and lipid and glycogen content in non-alcoholic steatohepatitis (NASH) model rats. Male Sprague-Dawley rats were randomly separated into 3 groups: the control group was fed standard chow;the NASH group was fed a methionine-choline-deficient high-fat diet (MCD);the NASH-exercise group was fed the MCD and exercised three times a week. Exercise training consisted of continuous running for thirty minutes at a 13 m/min, 6° slope on a motor-driven rodent treadmill for 6 weeks. Mitochondria content in NASH group decreased in the both fiber types compared with those of the control group. As compared between the NASH and NASH-exercise groups, however, exercise not only promoted significant improvements in liver fibrosis and cirrhosis and triglyceride (TG) content but also increased mitochondria content in type I muscle fiber in particular. These data suggest that exercise improved hepatic steatosis in NASH model rats and can prevent the progression of NASH.
