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81.
Ordóñez RM Zampini IC Rodríguez F Cattaneo F Sayago JE Isla MI 《Journal of agricultural and food chemistry》2011,59(16):8655-8660
In this study, antioxidant activities in free-radical-mediated oxidative systems and the genotoxic/antigenotoxic effects of two proteins with molecular mass around 17 kDa, purified from Solanum betaceum fruits (cyphomine) and Solanum tuberosum tubers (solamarine), were investigated. Both proteins inhibited uric acid formation with IC(50) values between 55 and 60 μg/mL, and both proteins were able to reduce oxidative damage by scavenging hydroxyl radicals and superoxide anion in a dose-dependent manner. Furthermore, the DPPH? reduction assay showed SC(50) values of 55-73 μg/mL. Cyphomine and solamarine were able to retain their antioxidant activity after heat treatment at 80 °C for 15 min. Allium cepa and Salmonella /microsome assays showed no genotoxic and mutagenic effects. Solamarine showed an antimutagenic effect against a direct mutagen (4-nitro-o-phenylenediamine). Consequently, the present study showed that the investigated proteins are promising ingredients for the development of functional foods with a beneficial impact on human health and an important source for the production of bioactive peptides. 相似文献
82.
María Gómez-Brandón Cristina Lazcano Marta Lores Jorge Domínguez 《Applied soil ecology》2010,44(3):237-244
The impact of detritivorous earthworms (Eisenia andrei) on microbial community structure and function in grape marc, a lignocellulosic enriched plant residue, was investigated in a mesocosm experiment. Analysis of carbon and nitrogen pools was also carried out in order to evaluate how changes in microbial communities affect plant residue decomposition. The grape marc was completely processed after fifteen days as a result of the high density of earthworms present and the rapid gut transit time. Eisenia andrei had a large impact on the structure of the microbial community, as revealed by phospholipid fatty acid analysis. Earthworm activity reduced the abundance of both bacterial (except for Gram-negative bacteria) and fungal PLFA biomarkers relative to the control values. Decreases in microbial activity and in protease and cellulase activities were also attributable to the presence of earthworms. Moreover, earthworms strongly modified the substrate utilization patterns of microbial communities, as revealed by BIOLOG analysis. The presence of earthworms led to an increase in the utilization of some amino acids and polymers, which reached a higher substrate diversity value than that in the control mesocosm. The differences in microbial communities were accompanied by a reduction in the total C content and the labile C pool, relative to the control, although there were no significant differences in either cellulose or hemicellulose contents. However, total N content increased in both mesocosms – with and without earthworms – and the concentration of NH4+ was also enhanced by earthworm activity. The results indicate that detritivorous earthworms play a key role in decomposing fresh plant residues in the short term via their intensive interactions with microbial communities. 相似文献
83.
Jorge Paz-Ferreiro Carmen Trasar-Cepeda Ma Carmen Leirós Socorro Seoane Fernando Gil-Sotres 《European Journal of Soil Biology》2010,46(2):136-143
Biochemical properties are considered to be the best indicators available at present for assessing soil quality. However, there are still many gaps in our knowledge about how these properties are affected by abiotic factors and how these factors interact with soil management. With the aim of understanding how climate and soil management affect soil biochemical properties in grasslands soils from a temperate-humid area (Galicia, NW Spain), a total of 60 soils were analyzed for several microbial and biochemical properties. Grasslands were divided into groups according to the type of management applied (native compared with intensive) and to the climate in the area where they were sampled (Mediterranean subhumid with centroeuropean drift climate compared with Atlantic climate). We found that management had a greater influence on soil biochemical properties than climate. Altitude, which strongly influences climate in the region where the soils were analyzed, was found to be a significant factor that affected most soil biochemical properties. In conclusion, the results show that microbially-mediated processes are greatly affected by both, management and abiotic factors and that, for some properties (like net N mineralization and cellulase and casein-protease activities), abiotic factors can have an important influence on soil biochemical properties. 相似文献
84.
区域地下水位插值的整体-局部组合方法 总被引:1,自引:1,他引:1
利用趋势面分析法进行空间插值时估值趋势面光滑,对局部数据起伏较大的区域插值精度不理想。针对这一问题,该文基于非平稳地下水位数据,在用趋势面分析法进行空间插值的基础上,运用Yamamoto提出的修正的普通克里金法对区域残差进行了空间插值。将趋势面分析法的估计值与残差估计值相加,得到区域地下水位的空间分布规律。结果表明,采用这种整体与局部结合的组合插值方法,地下水位插值的结果比趋势面分析结果更接近实际情况,在保证全局最优的同时较好地解决了估值趋势面光滑、局部插值精度低的问题,更能真实地反映区域地下水位空间分布特征。 相似文献
85.
Alejandra G. Vovides Jorge López-Portillo Yoav Bashan 《Biology and Fertility of Soils》2011,47(5):567-576
Microbial processes are key elements in determining the productivity of mangroves, and reductions in these processes reflect
the loss of microbial biodiversity and function due to fabricated disturbances. Because nitrogen is a major limiting nutrient
for the productivity of these ecosystems, the goal of this study was to determine profiles of inorganic nitrogen combined
with several environmental parameters, all in relation to the degree of long-term hydraulic impairment of a tropical, monospecific
black mangrove (Avicennia germinans) forest that showed degradation ranging from total loss of mangrove cover to no disturbance. N2-fixation, oxygen levels, and nitrite contents decreased significantly with the severity of the disturbance, and almost null
levels were reached in the completely degraded zone, whereas salinity achieved very high values. Concomitantly, total N, ammonium,
and P contents and ammonia volatilization increased significantly. Pore-water temperature and pH increased moderately. Other
soil physical properties (sand, silt, clay, organic matter, and total C), which varied among the sampling sites, were not
correlated with the level of disturbance. Principal component analyses, including environmental and biological parameters,
suggested that the most significant finding was the considerable loss of N2-fixation with increasing impairment, which was concomitant with significant increases in volatilization of ammonia and salinity.
The results show that microbial N-cycling processes are highly sensitive to salinity and to man-made disturbances that modify
the water level and flow. 相似文献
86.
87.
Diversity of native rice (Oryza Poaceae:) species of Costa Rica 总被引:1,自引:0,他引:1
Alejandro Zamora Cynthia Barboza Jorge Lobo Ana M. Espinoza 《Genetic Resources and Crop Evolution》2003,50(8):855-870
We found several populations of wild Oryza species in the lowlands of Costa Rica. The plants showed extensive morphological variation, suggesting the presence of several species. In the morphologic study, 33 traits were scored for plants of all the species. A principal component analysis revealed the significant morphological separation of the different species. The analyses indicated that there are three species, O. grandiglumis, O. latifolia and O. glumaepatula. Two putative hybrid types were found, both significantly differing in their morphology from the known species and intermediate at several traits. O. grandiglumis is a new record for Costa Rican flora. Its main population is located in Caño Negro Wildlife Refuge, Los Chiles, Alajuela. O. latifolia is distributed throughout the lowlands of the country and the plants of the Atlantic slope are significantly bigger in general habit than those of the Guanacaste area. During this study a population of O. glumaepatula of hundreds of thousands of plants was discovered in the Medio Queso River wetland, Los Chiles, Alajuela. This population is the most important source of genes for cultivar's improvement from the primary gene pool of rice in Costa Rica. The small ligule and the wide flag leaf characteristic of the two CCDD species separated them from the AA diploid O. glumaepatula. Seed size, ligule size, number of branches in the panicle, plant height and sterile lemma length are all bigger in O. grandiglumis, and influenced the second factor that separated the CCDD species in two discrete clusters. The species found offer great possibilities for the improvement of rice cultivars and they should be thoroughly studied and appropriately protected. 相似文献
88.
Bernardo AE Garcia RN Adachi M Angeles JG Kaga A Ishimoto M Utsumi S Tecson-Mendoza EM 《Journal of agricultural and food chemistry》2004,52(9):2552-2560
Three isoforms of the cDNA of the major 8S globulin of mungbean, 8Salpha, 8Salpha', and 8Sbeta, were isolated, cloned, and characterized. The cDNA sequences of 8Salpha, 8Salpha', and 8Sbeta had open reading frames of 1362, 1359 or 1362, and 1359 bp, respectively, which code for 454, 453 or 454, and 453 amino acids corresponding to molecular weights of 51 973, 51 627 or 51 758, and 51 779, respectively. Homology in terms of cDNA and amino acid sequences was 91-92% between 8Salpha and 8Salpha', 87% between 8Salpha and 8Sbeta, and 86-88% between 8Salpha' and 8Sbeta. The signal peptide was found to be 1-25, 1-24 or 25, and 1-23 for 8Salpha, 8Salpha', and 8Sbeta, respectively, using the signalP website (Nielsen, H.; Engelbrecht, J.; Brunak, S.; von Heijne, G. Protein Eng. 1997, 10, 1-6). The propeptide was determined to be IVHREN. A single site for glycosylation (N-X-S/T) was observed about 90 amino acids from the C terminus. Homology between mungbean 8S isoforms and other 7-8S proteins ranged from 45 to 68% within members of the legume family and 29 to 34% for crops of different species. The major isoform 8Salpha was expressed in Escherichia coli and purified by successive ammonium sulfate fractionation, hydrophobic interaction, and Mono Q column chromatography. The recombinant 8Salpha, but not the native form, was successfully crystallized producing rhombohedral crystals. 相似文献
89.
Castro SM Van Loey A Saraiva JA Smout C Hendrickx M 《Journal of agricultural and food chemistry》2004,52(18):5724-5729
Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 degrees C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 degrees C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55-57 degrees C) and a biphasic model for higher temperatures (58-70 degrees C). The enzyme showed a stable behavior toward high-pressure/temperature treatments. 相似文献
90.
The purpose of the present work was to examine whether partial acid hydrolysis (PAH) of a high‐amylose maize starch (ae‐VII) would enhance the effects of hydrothermal treatments to produce granular resistant starch (RS) that is stable to further heat treatment at atmospheric pressure. PAH ae‐VII starches were prepared by heating 35% (w/v) suspensions with 1% (w/w) HCl at 25°C for 6, 30, and 78 hr. Native and PAH starches were then treated by annealing (ANN) or heat‐moisture treatment (HMT). ANN was done at 70% moisture at 50, 60, or 70°C for 24 hr, and HMT was done at 30% moisture at 100, 120, or 140°C for 80 min. RS that survives boiling during analysis was determined by a modification of the AOAC method for determining total dietary fiber. RS was also determined by the Englyst method. Little change in the gelatinization enthalpy was found for ae‐VII starch after PAH, ANN, or HMT as individual treatments. After PAH, either ANN or HMT led to decreased gelatinization enthalpy. HMT and ANN alone increased boiling‐stable RS but decreased total RS. After PAH of ae‐VII, either ANN or HMT tended to increase the yield of boiling‐stable granular RS, with the greatest yield (≤63.2%) observed for HMT. 相似文献