A breeding strategy for widening the germplasm of Brassica napus was proposed by introgression of the A^r subgenome of B. rapa （A^rA^r） and C^c of B. carinata （B^cB^cC^cC^c） into natural B. napus （AnAncncn）. The...A breeding strategy for widening the germplasm of Brassica napus was proposed by introgression of the A^r subgenome of B. rapa （A^rA^r） and C^c of B. carinata （B^cB^cC^cC^c） into natural B. napus （AnAncncn）. The progenies with 38 chromosomes that were derived from the self-pollinated seeds of pentaploid hybrids （A^rA^nB^cC^cC^n） were used for further research. Some of the partial new-typed B. napus showed normal meiotic behavior, high portion of germinated pollen and normal embryological development. This indicates that the selected new-typed B. napus had a balanced genetic base. Molecular analysis showed that about 50% of the genome in the new-typed B. napus was replaced by A^r and C^c subgenome from B. rapa and B. carinata. Considering the genetic diversity among different lines of new-typed B. napus, it was deduced that the introgression of the genomic components from B, rapa and B. carinata could widen the genetic diversity of rapeseed.展开更多
This study aimed to purify and determine antioxidant activities of different fractions obtained during the purification process of phycocyanin from Spirulina platensis. The dried powder of Spirulina platensis, after g...This study aimed to purify and determine antioxidant activities of different fractions obtained during the purification process of phycocyanin from Spirulina platensis. The dried powder of Spirulina platensis, after ground with sands, was extracted with 50 mM sodium phosphate buffer at pH 6.8 before centrifuged to precipitate unwanted proteins. Then the supernatant was separated by celit column to obtain semi-pure phycocyanin and further purified by treated with ammonium sulfate. The purity of phycocyanin was monitored by measuring the absorbance spectrum from 200 to 700 nm. Its purity ratio A620A280 was determined. The antioxidant activities of the obtained phycocyanin were determined by 2,2＇-azino-bis（3-ethylbenzthiazoline-6-sulphonic acid） （ABTS） assay and lipid peroxidation （linoleie acid） assay. The purity ratio of phycocyanin in the Spirulina crude extract was 0.36 and increased to 2.68 after purification. The fraction with the highest purity ratio of phycocyanin demonstrated the hightest antioxidant activities. For ABTS assay, it presented the Vitamin C Equivalent Antioxidant Capacity （VCEAC） value of 0.0405 ±0.0002 mg of ascorbic acid/mg of sample and the Trolox Equivalent Antioxidant Capacity （TEAC） value of 0.0485 ±0.0002 mg oftrolox/mg of sample respectively. The result from lipid peroxidation assay exhibited IC50 value of 5.9336 ±0.2565 mg/mL. The purification of Spirulinaplatensis crude extract obtained from this study increased the purity ratio of phycocyanin and its antioxidant activities. This will be further investigated for the development into anti-aging cosmetic products.展开更多
The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phospho...The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phosphor were investigated usingX-ray diffraction (XRD) and a fluorescence spectrophotometer. The excitation spectrum exhibited a broad band between 230nm and 400 nm and the emission peaking at about 470 nm was observed, which originated from the allowed f-d transition ofEu2+ions at Ba2+sites. Owing to the different optimal concentrations under different excitation wavelengths (254 nm and 365nm), the energy-transfer mechanism in this phosphor has changed from the dipole-dipole interaction to the exchange interac-tion of Eu2+ions.展开更多
The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argenti...The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argentifolii Bellows and Perring), on various ornamental andvegetable crops under greenhouse conditions. The development, survivorship, and fecundity of D.catalinae feeding on B. tabaci biotype B on collard plants were determined in the laboratory, andthe age-specific life table parameters were analyzed based on the life history data. Developmentaltime was 4.0,1.9,1.1,1.4,5.2, and 5.3 days for eggs, first, second, third, fourth instars, andpupae, respectively, with an average of 18.9 days from oviposition to adult emergence for bothsexes, 19.0 days for females, and 18.8 days for males. Adult longevities averaged 146.6 days forboth sexes, 122.6 days for females, and 170.5 days for males. After an average 4.9 dayspreoviposition period, females laid a mean of 5.6 eggs per day over a 97.0-day period. Netreproductive rate (R_0) and gross reproductive rate (Σm_x) were estimated by life table analysis at276.8 and 325.1, respectively. Generation time (T) and doubling time (DT) were 35.6 and 4.8 daysrespectively, and the intrinsic rate of natural population increase (r_m) was estimated at 0.158, orl= 1.171 for the finite rate of increase. The r_m value of D. catalinae is similar to or higherthan those of the whitefly feeding on most vegetable and ornamental crops, indicating that theladybeetle is capable of regulating populations of B. tabaci biotype B and other whiteflies undergreenhouse conditions.展开更多
基金This study was supported by High Project of Science and Technology in China (No. 2001AA21110103)Doctoral Foundation of Education Department in China (No. 20020504009).
文摘A breeding strategy for widening the germplasm of Brassica napus was proposed by introgression of the A^r subgenome of B. rapa （A^rA^r） and C^c of B. carinata （B^cB^cC^cC^c） into natural B. napus （AnAncncn）. The progenies with 38 chromosomes that were derived from the self-pollinated seeds of pentaploid hybrids （A^rA^nB^cC^cC^n） were used for further research. Some of the partial new-typed B. napus showed normal meiotic behavior, high portion of germinated pollen and normal embryological development. This indicates that the selected new-typed B. napus had a balanced genetic base. Molecular analysis showed that about 50% of the genome in the new-typed B. napus was replaced by A^r and C^c subgenome from B. rapa and B. carinata. Considering the genetic diversity among different lines of new-typed B. napus, it was deduced that the introgression of the genomic components from B, rapa and B. carinata could widen the genetic diversity of rapeseed.
文摘This study aimed to purify and determine antioxidant activities of different fractions obtained during the purification process of phycocyanin from Spirulina platensis. The dried powder of Spirulina platensis, after ground with sands, was extracted with 50 mM sodium phosphate buffer at pH 6.8 before centrifuged to precipitate unwanted proteins. Then the supernatant was separated by celit column to obtain semi-pure phycocyanin and further purified by treated with ammonium sulfate. The purity of phycocyanin was monitored by measuring the absorbance spectrum from 200 to 700 nm. Its purity ratio A620A280 was determined. The antioxidant activities of the obtained phycocyanin were determined by 2,2＇-azino-bis（3-ethylbenzthiazoline-6-sulphonic acid） （ABTS） assay and lipid peroxidation （linoleie acid） assay. The purity ratio of phycocyanin in the Spirulina crude extract was 0.36 and increased to 2.68 after purification. The fraction with the highest purity ratio of phycocyanin demonstrated the hightest antioxidant activities. For ABTS assay, it presented the Vitamin C Equivalent Antioxidant Capacity （VCEAC） value of 0.0405 ±0.0002 mg of ascorbic acid/mg of sample and the Trolox Equivalent Antioxidant Capacity （TEAC） value of 0.0485 ±0.0002 mg oftrolox/mg of sample respectively. The result from lipid peroxidation assay exhibited IC50 value of 5.9336 ±0.2565 mg/mL. The purification of Spirulinaplatensis crude extract obtained from this study increased the purity ratio of phycocyanin and its antioxidant activities. This will be further investigated for the development into anti-aging cosmetic products.
基金supported by the Scientific and Technological Project of Chongqing, China (Grant No. CSTC, 2009AB4171)the Innovation Foundation for Technology Based Firms of Ministry of Science and Technology, China (Grant No. 04C26225100807)
文摘The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phosphor were investigated usingX-ray diffraction (XRD) and a fluorescence spectrophotometer. The excitation spectrum exhibited a broad band between 230nm and 400 nm and the emission peaking at about 470 nm was observed, which originated from the allowed f-d transition ofEu2+ions at Ba2+sites. Owing to the different optimal concentrations under different excitation wavelengths (254 nm and 365nm), the energy-transfer mechanism in this phosphor has changed from the dipole-dipole interaction to the exchange interac-tion of Eu2+ions.
文摘The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argentifolii Bellows and Perring), on various ornamental andvegetable crops under greenhouse conditions. The development, survivorship, and fecundity of D.catalinae feeding on B. tabaci biotype B on collard plants were determined in the laboratory, andthe age-specific life table parameters were analyzed based on the life history data. Developmentaltime was 4.0,1.9,1.1,1.4,5.2, and 5.3 days for eggs, first, second, third, fourth instars, andpupae, respectively, with an average of 18.9 days from oviposition to adult emergence for bothsexes, 19.0 days for females, and 18.8 days for males. Adult longevities averaged 146.6 days forboth sexes, 122.6 days for females, and 170.5 days for males. After an average 4.9 dayspreoviposition period, females laid a mean of 5.6 eggs per day over a 97.0-day period. Netreproductive rate (R_0) and gross reproductive rate (Σm_x) were estimated by life table analysis at276.8 and 325.1, respectively. Generation time (T) and doubling time (DT) were 35.6 and 4.8 daysrespectively, and the intrinsic rate of natural population increase (r_m) was estimated at 0.158, orl= 1.171 for the finite rate of increase. The r_m value of D. catalinae is similar to or higherthan those of the whitefly feeding on most vegetable and ornamental crops, indicating that theladybeetle is capable of regulating populations of B. tabaci biotype B and other whiteflies undergreenhouse conditions.
