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61.
This study was designed to determine the changes in saponin content in American ginseng berries after treatment by heating and to assess the anticancer effects of the extracts. After steaming treatment (100-120 degrees C for 1 h, and 120 degrees C for 0.5-4 h), the content of seven ginsenosides, Rg1, Re, Rb1, Rc, Rb2, Rb3, and Rd, decreased; the content of five ginsenosides, Rh1, Rg2, 20R-Rg2, Rg3, and Rh2, increased. Rg3, a previously identified anticancer ginsenoside, increased significantly. Two hours of steaming at 120 degrees C increased the content of ginsenoside Rg3 to a greater degree than other tested ginsenosides. When human colorectal cancer cells were treated with 0.5 mg/mL steamed berry extract (120 degrees C 2 h), the antiproliferation effects were 97.8% for HCT-116 and 99.6% for SW-480 cells. At the same treatment concentration, the effects of unsteamed berry extract were 34.1% for HCT-116 and 4.9% for SW-480 cells. After staining with Hoechst 33258, apoptotic cells increased significantly by treatment with steamed berry extract compared with unheated extracts. Induction of apoptosis activity was confirmed by flow cytometry after staining with annexin V/PI. The steaming of American ginseng berries augments ginsenoside Rg3 content and increases the antiproliferative effects on two human colorectal cancer cell lines.  相似文献   
62.
Inheritance of resistance to a wheat midge, Sitodiplosis mosellana (Géhin), was investigated in spring wheats derived from nine resistant winter wheat cultivars. F1 hybrids were obtained from crosses between resistant winter wheats and susceptible spring wheats, and used to generate doubled haploid populations. These populations segregated in a ratio of 1:1 resistant to susceptible, indicating that a single gene confers the resistance. The F2 progeny from an intercross among spring wheats derived from the nine resistance sources did not segregate for resistance. Therefore, the same gene confers resistance in all nine sources of resistance, although other genes probably affect expression because the level of resistance varied among lines. Heterozygous plants from five crosses between diverse susceptible and resistant spring wheat parents all showed intermediate levels of response, indicating that resistance is partly dominant. Susceptible plants were reliably discriminated from heterozygous or homozygous resistant ones in laboratory tests, based on the survival and development of wheat midge larvae on one or two spikes. This powerful resistance gene, designated Sm1, is simply inherited and can be incorporated readily into breeding programmes for spring or winter wheat. However, the use of this gene by itself may lead to the evolution of a virulent population, once a resistant cultivar is widely grown.  相似文献   
63.
Taing Aung  Hugh Thomas 《Euphytica》1978,27(3):731-739
Summary The gene for mildew resistance has been succesfully transferred into the cultivated oat from the wild oat species Avena barbata by means of an irradiation-induced translocation. The translocation has been shown to involve the long arm of chromosome ST21 of A. sativa, the short arm, the centromere and a segment of the long arm of the barbata chromosome.The transmission of the translocation is normal in the cultivar Manod in which it was originally isolated. When the translocation was transferred into other cultivars of oats, transmission through the male gametes was found to be impaired in some genotypic backgrounds. However, there was no evidence that the translocation had any deleterious effect on development and fertility in a range of cultivars.The translocation was shown to involve an exchange between nonhomoeologous chromosomes.The behaviour of the translocation in diverse genotypes indicated that the translocation was a new source of mildew resistance that could be easily used in a breeding programme.  相似文献   
64.
本研究中假设可以通过两种方法增强滤化床反应器中有机固体废弃物的厌氧发酵:①通过提高滤化床的孔隙度;②通过褐腐菌或厌氧消化残留物强化滤化床。将牛粪做为有机固体废弃物的模型,开心果半壳为惰性添加剂,用以提高滤化床的孔隙度。此试验证实了上述的假设。以产生的挥发性脂肪酸和可溶性化学需氧量为基础将厌氧发酵提高的程度进行量化。此研究结果显示,在高孔隙度、褐腐菌或厌氧消化残留物强化滤化床的条件下,  相似文献   
65.
Bradyrhizobium species are symbiotic partners of soybean plants. However, some Bradyrhizobium bacteria do not form functional nodules on the roots of Rj4 genotype soybean cultivars. Our objective was to identify the strains of Bradyrhizobium (i.e., type C strains) that are least competent to form nodules on the roots of this plant genotype. We checked (i) previously isolated type C strains of Myanmar Bradyrhizobium elkanii (MMY6-1, MMY6-2, and MMY6-5), (ii) previously isolated type C strains of Myanmarese Bradyrhizobium spp. (MMY3-5 and MMY3-7), and (iii) strain Is-34 of B. japonicum, for nodule formation when associated with Rj4 and other Rj genotype soybeans. Strains in groups (i), (ii), and (iii) are known to be incompatible with Rj4 soybean genotypes. MMY3-5 and MMY3-7 produced functional nodules when associated with Rj4 and other Rj genotype soybean cultivars, except Hill (Rj4) cultivar. The ratios of ineffective nodule numbers/total nodule numbers (I/T ratios) for MMY6-1, MMY6-2, MMY6-5, and Is-34 in association with Rj4 soybean cultivars were > 0.5, demonstrating incompatibility between these bacterial strains and the Rj4 genotype. Interestingly, the I/T ratios of MMY6-1 and MMY6-2 were higher than that of Is-34 in almost all Rj4 soybean cultivars. Thus, the nodule-forming abilities of the B. elkanii strains MMY6-1 and MMY6-2 were strongly suppressed in Rj4 soybean cultivars; these strains may therefore be useful to identify the Rj4 genotype in soybean cultivars.  相似文献   
66.
Ravenna grass, Erianthus ravennae (L.) Beauv. (E. ravennae) is a potential high biomass-energy crop with low input requirements. Iron (Fe) deficiency in calcareous soils is a widespread agronomic problem which reduces crop yields. Fe is sparingly soluble under aerobic conditions at high soil pH, such as in calcareous soils; therefore, plants cannot take up enough Fe. Increasing crop productivity of giant grasses, such as Ravenna grass in calcareous soil, has a positive effect by alleviating environmental problems. However, the growth character in calcareous soil and Fe homeostatic trait of Ravenna grass are largely unknown. In this study, we analyzed characteristics of Ravenna grass. The growth of E. ravennae plants were impaired in calcareous soil compared to those in the normal soil. In calcareous soil, the growth of E. ravennae plants differ among the water and fertilizer conditions; E. ravennae plants were grown better in the submerged condition adding micronutrient among conditions. These results suggested that impaired growth of E. ravennae in calcareous soil might be micronutrient shortage. We found that E. ravennae roots possess Fe reductase activities which were upregulated under Fe-deficient conditions. E. ravennae produced and secreted mugineic acid (MA) and deoxymugineic acid (DMA) to acquire Fe from the soil. The amount of MA was higher than that of DMA. Thus, E. ravennae might have both partial Strategy-I and Strategy-II Fe uptake systems. E. ravennae intercropped with transgenic rice plants producing and secreting MA through the introduction of the barley MA synthase gene showed improved growth compared to monocropped E. ravennae plants, suggesting that the increased amounts of MA enhanced their tolerance to Fe deficiency. Our results suggest that there is a considerable potential to improve the growth of E. ravennae plants in calcareous soils by enhancement of their Fe uptake systems through increase of MA production.  相似文献   
67.
68.
Kerber ER  Aung T 《Phytopathology》1999,89(6):518-521
ABSTRACT The common wheat cultivar Thatcher and the backcross derivative Canthatch are moderately or fully susceptible to several races of stem rust because of a suppressor on chromosome 7DL that inhibits the expression of the relevant resistance gene(s). The incorporation of leaf rust resistance gene Lr34 into 'Thatcher' is known to enhance stem rust resistance. The effect of this gene in a 'Canthatch' background and its relationship with the 7DL suppressor were determined by replacing chromosome 7D of 'Canthatch' with 7D of 'Chinese Spring', which possesses Lr34 on the short arm. 'Canthatch' nullisomic 7D was crossed with 'Chinese Spring', followed by a succession of backcrosses to the nullisomic recurrent parent. Homozygous resistant disomic and monosomic substitution lines were recovered that exhibited the same resistant reaction as that of 'Thatcher' possessing Lr34 and as that of 'Canthatch' nullisomic 7D, in which the 7DL suppressor is absent. The results indicate that, in 'Canthatch', Lr34 permits expression of resistance genes normally inhibited by the 7DL suppressor. Furthermore, it is likely that, in 'Thatcher' and 'Thatcher' back-cross derivatives, Lr34 inactivates the 7DL suppressor.  相似文献   
69.
Asian cultivated rice Oryza sativa L. was domesticated from its wild ancestor, O. rufipogon. During domestication, the cultivated rice lost its seed-shattering behaviour. Previous studies have shown that two major quantitative trait loci (QTLs; qSH1 and sh4) are responsible for the seed-shattering degree. Here, we produced introgression lines carrying non-functional alleles from O. sativa ‘Nipponbare’ at the two major QTLs in the genetic background of wild rice O. rufipogon W630, and examined the effects of the two QTLs on seed shattering and abscission layer formation. The introgression lines, with Nipponbare alleles at either or both loci, showed complete or partial abscission layer formation, respectively, indicating that other unknown loci might be involved in enhancing seed shattering in wild rice. We detected a single QTL named qSH3 regulating seed-shattering degree using an F2 population between Nipponbare and the introgression line carrying Nipponbare alleles at the two QTLs. Although we generated an introgression line for qSH3 alone, no effects on seed shattering were observed. However, a significant effect on seed-shattering degree was observed for the introgression line carrying Nipponbare alleles at qSH3 and the two QTLs, suggesting an important role of qSH3 on seed shattering in coordination with the two QTLs.  相似文献   
70.
The Ayeyarwaddy delta region in the south‐west of Myanmar is the main agricultural and rice‐growing area. The region has a high density of duck and backyard chicken populations with low biosecurity. The objective of this study was to analyse risk factors for avian influenza (H5) in the Ayeyarwaddy delta region, Myanmar. A case–control risk factor study was conducted from April to June 2010 by individual interviews including risk factor questionnaires given to duck farmers (n = 50) in five townships in the Ayeyarwaddy delta region, Myanmar. Risk factor analyses were conducted using univariate analysis and multivariate logistic regression model with backward stepwise (wald) method. The results showed significant risk factors for AI (H5) sero‐positivity in ducks were wooden egg box containers (OR = 52.7, 95% CI = 2.34–1188, P = 0.013) and water sourced from wetlands (OR = 30.7, 95% CI = 1.96–481.6, P = 0.015). Conversely, the cleaning of reusable egg containers was determined as a protective factor (OR = 0.03, 95% CI = 0.00–0.42, P = 0.01). In conclusion, this study identified risk factors for AI (H5) in duck farms and the importance of avian influenza prevention and control.  相似文献   
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