Antioxidant properties of low molecular weight phenols present in the mediterranean diet     

Briante R  Febbraio F  Nucci R 《Journal of agricultural and food chemistry》2003,51(24):6975-6981

The antioxidant capacity of low molecular weight phenols found in olive fruit and in virgin olive oil has been investigated. The radical scavenging activity of some of the investigated phenols is higher than that of the most used antioxidants, and among them, 3,4- or 2,5-dihydroxyl phenols are also able to chelate copper ions leading to chelates that are only slightly active in the promotion of free radical reactions. The ability of tested phenols to reduce Cu(II) and their activity-structure relationships was also studied, showing that their reducing capacity is connected to the presence of a specific ligand of the reduced ion. The number of reduced ions per mole of phenol is lower than that calculated for some flavonols and isoflavones so exerting a lower prooxidant action. This fact may be important in vivo when free transition metal ions are involved in oxidation processes.  相似文献   

Construction of a crop—wild hybrid population for broadening genetic diversity in cultivated sunflower and first evaluation of its combining ability: the concept of neodomestication     

Hamidreza Nooryazdan  Hervé Serieys  Jacques David  Roberto Bacilieri  André J. Bervillé 《Euphytica》2011,178(2):159-175

The genetic base of sunflower elite lines is very narrow, due to many years of selection and breeding. To broaden the genetic diversity of the cultivated sunflower, in 1995 73 wild sunflower populations were crossed with 3 cultivated lines (Testers), and 219 hybrid offspring’s were evaluated in the field. GCA and SCA effects were computed suggesting for all traits a genetic potential for improvement through selection. Study of the hybrids revealed that the wild accessions bear different genetic abilities to combine with the testers for traits of morphological architecture, phenology and yield (seed weight and seed oil). The variance due to GCA and SCA showed that gene action was additive for days to flowering, branching and plant height. Genotypes derived from the same geographic origin may have either good or poor general combing ability. The correlation between GCA and per se genotype performance was positive for all traits except for seed oil content. This was the first attempt to evaluate wild-cultivated hybrids in sunflower on a large scale and will be the starting point for the management of hybrid Helianthus annuus populations for breeding. GCA and SCA estimations will facilitate the definition of strategies to manage and exploit the natural diversity for this crop.  相似文献   

Liberalization of Peru's formal seed sector     

Jeffery W. Bentley  Robert Tripp  Roberto Delgado de la Flor 《Agriculture and Human Values》2001,18(3):319-331

During the 1990s, the Government of Peru began to aggressivelyprivatize agriculture. The government stopped loaning money to farmers' cooperatives and closed the government rice-buying company. The government even rented out most of its researchstations and many senior scientists lost their jobs. As part of this trend, the government eliminated its seed certification agency. Instead, private seed certification committees were set up with USAID funding and technical advise from a US university. The committees were supposed to become self-financing (bycertifying seed grown by small seed producers) and each committee was supposed to encourage the development of a group of small seed-producing firms, clustered around the seedcertification agency. The amazing thing is that many of the seed committees actually accomplished these goals. The agronomists who staffed the committees stood by their jobs,even after US funding ended, even though the committees' income was (at best) modest, and occasionally under the threat of violence from the extreme left. Some seed certificationcommittees failed and others did not. Some of the problems with Peruvian agricultural liberalization can be seen in regard to the seed programs of maize, rice, potatoes, and beans. For example, the government abandoned most research, yet could not resist creating certain distortions in the seed market (e.g.,buying large amounts of seed and distributing them for political ends).  相似文献   

Dentate gyrus NMDA receptors mediate rapid pattern separation in the hippocampal network     

McHugh TJ  Jones MW  Quinn JJ  Balthasar N  Coppari R  Elmquist JK  Lowell BB  Fanselow MS  Wilson MA  Tonegawa S 《Science (New York, N.Y.)》2007,317(5834):94-99

Forming distinct representations of multiple contexts, places, and episodes is a crucial function of the hippocampus. The dentate gyrus subregion has been suggested to fulfill this role. We have tested this hypothesis by generating and analyzing a mouse strain that lacks the gene encoding the essential subunit of the N-methyl-d-aspartate (NMDA) receptor NR1, specifically in dentate gyrus granule cells. The mutant mice performed normally in contextual fear conditioning, but were impaired in the ability to distinguish two similar contexts. A significant reduction in the context-specific modulation of firing rate was observed in the CA3 pyramidal cells when the mutant mice were transferred from one context to another. These results provide evidence that NMDA receptors in the granule cells of the dentate gyrus play a crucial role in the process of pattern separation.  相似文献   

Correction of ADA-SCID by stem cell gene therapy combined with nonmyeloablative conditioning     

Aiuti A  Slavin S  Aker M  Ficara F  Deola S  Mortellaro A  Morecki S  Andolfi G  Tabucchi A  Carlucci F  Marinello E  Cattaneo F  Vai S  Servida P  Miniero R  Roncarolo MG  Bordignon C 《Science (New York, N.Y.)》2002,296(5577):2410-2413

Hematopoietic stem cell (HSC) gene therapy for adenosine deaminase (ADA)-deficient severe combined immunodeficiency (SCID) has shown limited clinical efficacy because of the small proportion of engrafted genetically corrected HSCs. We describe an improved protocol for gene transfer into HSCs associated with nonmyeloablative conditioning. This protocol was used in two patients for whom enzyme replacement therapy was not available, which allowed the effect of gene therapy alone to be evaluated. Sustained engraftment of engineered HSCs with differentiation into multiple lineages resulted in increased lymphocyte counts, improved immune functions (including antigen-specific responses), and lower toxic metabolites. Both patients are currently at home and clinically well, with normal growth and development. These results indicate the safety and efficacy of HSC gene therapy combined with nonmyeloablative conditioning for the treatment of SCID.  相似文献   

Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

Laser-induced selectivity for dimerization versus polymerization of butadiene under pressure     

Citroni M  Ceppatelli M  Bini R  Schettino V 《Science (New York, N.Y.)》2002,295(5562):2058-2060

The pressure-induced chemical reaction of liquid butadiene was studied by Fourier transform infrared spectroscopy in a diamond anvil cell. Dimerization was found to occur above 0.7 gigapascal, giving vinylcyclohexene according to a cyclo-addiction reaction and only a trace amount of polybutadiene forms. By irradiating the high-pressure sample with a few milliwatts of the 488-nanometer argon+ laser line, the dimerization was completely inhibited, and the rapid formation of pure trans-polybutadiene was observed. The use of different excitation wavelength allows us to emphasize the selectivity of the process and to identify the active role of the 2(1)Ag state in this pressure- and laser-induced chemical reaction.  相似文献   

Extracellular DNA plays a key role in deep-sea ecosystem functioning   总被引：1，自引：0，他引：1  

Dell'Anno A  Danovaro R 《Science (New York, N.Y.)》2005,309(5744):2179

The ecological role and biogeochemical relevance of extracellular DNA in the oceanic sediments are unknown. Our global estimates indicate that up to 0.45 gigatons of extracellular DNA are present in the top 10 centimeters of deep-sea sediments, representing the largest reservoir of DNA in the world oceans. We demonstrate that extracellular DNA accounts for about one fifth of the total organic phosphorus regeneration and provides almost half of the prokaryotic demand for organic phosphorus. It therefore plays a key role in deep-sea ecosystem functioning on a global scale.  相似文献   

Postsynaptic receptor trafficking underlying a form of associative learning     

Rumpel S  LeDoux J  Zador A  Malinow R 《Science (New York, N.Y.)》2005,308(5718):83-88

To elucidate molecular, cellular, and circuit changes that occur in the brain during learning, we investigated the role of a glutamate receptor subtype in fear conditioning. In this form of learning, animals associate two stimuli, such as a tone and a shock. Here we report that fear conditioning drives AMPA-type glutamate receptors into the synapse of a large fraction of postsynaptic neurons in the lateral amygdala, a brain structure essential for this learning process. Furthermore, memory was reduced if AMPA receptor synaptic incorporation was blocked in as few as 10 to 20% of lateral amygdala neurons. Thus, the encoding of memories in the lateral amygdala is mediated by AMPA receptor trafficking, is widely distributed, and displays little redundancy.  相似文献   

Diabetes and hypertension increases in a society with abdominal obesity: results of the Mexican National Health Survey 2000   总被引：5，自引：0，他引：5  

Sánchez-Castillo CP  Velásquez-Monroy O  Lara-Esqueda A  Berber A  Sepulveda J  Tapia-Conyer R  James WP 《Public health nutrition》2005,8(1):53-60

OBJECTIVES: To determine the prevalences of overweight, obesity, type 2 diabetes mellitus (DM) and hypertension (HT) in the Mexican population and compare them with those of a previous Mexican urban survey and an American survey. DESIGN: A structured, randomised, nationally representative Mexican sample was compared with a 1993 Mexican urban survey and the US Third National Health and Nutrition Examination Survey (NHANES III) of non-Hispanic Whites. SETTING: The Mexican National Health Survey 2000.Subjects: Subjects were 12,856 men and 28,332 women, aged 20-69 years, who had their body weight, height, waist circumference (WC), blood pressure and fasting capillary blood glucose measured. RESULTS: Mexican adult men and women had a high prevalence of overweight (41.3 and 36.3%, respectively) and obesity (19.4 and 29.0%, respectively), similar to those in the USA in 1988-1992 and exceeding those of the 1993 Mexican survey. The prevalence of HT was 33.3% in men and 25.6% in women, with inferred DM rates of 5.6 and 9.7%, respectively. Abdominal obesity affected 46.3% of men (WC>or=94 cm) and 81.4% of women (WC>or=80 cm). There was a high prevalence of abdominal obesity in normal-weight women, with co-morbidities relating better to WC than to body mass index (BMI) in both sexes. Rates of DM and HT exceeded US rates on a comparable BMI or WC basis in adults aged <50 years. CONCLUSION: The high prevalence of obesity and abdominal obesity in Mexicans is associated with markedly increased prevalences of DM and HT to levels comparable with, or even higher than, those in NHANES III of non-Hispanic Whites.  相似文献