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991.
Isabelle Blanckaert Martín Paredes-Flores Francisco J. Espinosa-García Daniel Piñero Rafael Lira 《Genetic Resources and Crop Evolution》2012,59(4):557-573
Use and management of wild and weedy species may involve artificial selection, which can determine morphological, physiological,
reproductive, and genetic divergences between wild and managed populations, resulting in the initial or incipient phases of
plant domestication. In this study we combined ethnobotanical, morphological, phytochemical and genetic information for analyzing
differences between managed and unmanaged populations of the Mexican edible weed, Epazote (Chenopodium ambrosioides L.), in Santa María Tecomavaca, Oaxaca, a rural community within the Tehuacán-Cuicatlán Biosphere Reserve, Mexico. Our hypothesis
was that differences in morphology (e.g. leave dimensions and density of pubescence), phytochemistry (e.g. flavor, odor, and
amount of strong scented and toxic compounds) and/or molecular genetic markers, between managed and wild populations of Epazote
in Santa María Tecomavaca, would indicate that managed populations have been and/or are under a process of incipient domestication.
Our results revealed the existence in the study area of morphological variants associated with a gradient of management intensity,
which involved apparent improved palatability correlated with a lowering of chemical defense. Most remarkably, we found agreement
in the groupings defined by the cluster analyses of morphological and genetic data. Although Epazote is considered a weed
or, at best, a minor crop, the results from four lines of evidence (cultural differentiation patterns, gigantism, reduction
in chemical defenses, toxic compounds and inheritance of adaptive traits) suggest the existence of an incipient domestication
process in the study zone. 相似文献
992.
Dapeng Zhang Windson July Martínez Elizabeth S. Johnson Eduardo Somarriba Wilberth Phillips-Mora Carlos Astorga Sue Mischke Lyndel W. Meinhardt 《Genetic Resources and Crop Evolution》2012,59(2):239-252
Cacao (Theobroma cacao L.) is an important economic crop in the Bolivian Amazon. Bolivian farmers both cultivate cacao, and extract fruits from
wild stands in the Beni River region and in valleys of the Andes foothills. The germplasm group traditionally used is presently
referred to as “Cacao Nacional Boliviano” (CNB). Using DNA fingerprinting technology based on microsatellite markers, we genotyped
164 Bolivian cacao accessions, including both cultivated and wild CNB accessions sampled from the Amazonian regions of La
Paz and Beni, and compared their SSR profiles with 78 reference Forastero accessions from Amazonian cacao populations, including
germplasm from the Ucayali region of Peru. Results of multivariate ordination and analysis of molecular variance show that
CNB cacao has a unique genetic profile that is significantly different from the known cacao germplasm groups in South America.
The results also show that cultivated CNB and wild CNB populations in the Beni River share a similar genetic profile, suggesting
that the cultivated CNB is of indigenous origin in Bolivia. The level of genetic diversity, measured by allele richness and
gene diversity in the Bolivian cacao, is moderately high, but was significantly lower than gene diversity in the other Amazonian
cacao populations. Significant spatial genetic structure was detected in the wild CNB population, using analysis of autocorrelation
(rc = 0.232; P < 0.001) and Mantel tests (Rxy = 0.276; P < 0.001). This finding is also highly valuable to support in situ conservation and sustainable use of CNB genetic diversity in Bolivia. 相似文献
993.
994.
Dynamics of storm-driven suspended sediments in a headwater catchment described by multivariable modeling 总被引:1,自引:0,他引:1
Milan Onderka Andreas Krein Sebastian Wrede Núria Martínez-Carreras Lucien Hoffmann 《Journal of Soils and Sediments》2012,12(4):620-635
Purpose
Previous research has shown that the rate at which suspended sediment is transported in watercourses depends primarily on discharge (Q) as the first-order control, but additional factors are thought to affect suspended sediment concentrations (SSC) as well. Among these, antecedent hydrological and meteorological conditions (e.g., rainfall depth and intensity, discharge prior to a runoff event and the duration of runoff events) may represent significant transport controlling mechanisms. Univariate models using Q–SSC rating curves often produce large scatter and nonlinearity, because many of the hydrological and biotic processes affecting the dynamics of sediment are non-linear and exhibit threshold behavior. The simulation of such highly non-linear processes is therefore an elusive task requiring consideration of several interrelated controlling variables. The aim of this study was to identify the major hydrological and meteorological controls determining the dynamics of SSC during storm-runoff events and the magnitude of SSC in a headwater catchment in Luxembourg. 相似文献995.
M. V. Cuevas M. J. Martín-Palomo A. Diaz-Espejo J. M. Torres-Ruiz C. M. Rodriguez-Dominguez A. Perez-Martin R. Pino-Mejías J. E. Fernández 《Irrigation Science》2013,31(4):729-746
We used sap flow and trunk diameter measurements for assessing water stress in a high-density ‘Arbequina’ olive orchard with control trees irrigated to replace 100 % of the crop water needs, and 60RDI and 30RDI trees, in which irrigation replaced ca. 60 and 30 % of the control, respectively. We calculated the daily difference for both tree water consumption ( $ D_{{E_{\text{p}} }} $ ) and maximum trunk diameter (D MXTD) between RDI trees and control trees. The seasonal dynamics of $ D_{{E_{\text{p}} }} $ agreed reasonably well with that of the stem water potential. We identified peculiarities on the response $ D_{{E_{\text{p}} }} $ to changes in water stressing conditions, which must be taken into account when using the index. An analysis of the water stress variability in the orchard is required for choosing the instrumented trees. The reliability of the D MXTD index was poorer than that of $ D_{{E_{\text{p}} }} $ . The maximum daily shrinkage (MDS) was not a reliable water stress indicator. 相似文献
996.
Transpiration of table grape (Vitis vinifera L.) trained on an overhead trellis system under netting
K. Suvočarev O. Blanco J. M. Faci E. T. Medina A. Martínez-Cob 《Irrigation Science》2013,31(6):1289-1302
The quantification of transpiration and corresponding basal crop coefficients is crucial for appropriate irrigation scheduling of drip-irrigated crops. Besides basal crop coefficients already published, there is the announcing need for setting values for the new growing practices such as cropping under netting. In this paper, measurements of unstressed table grape transpiration and basal crop coefficients under netting have been taken. Vineyards of two seedless cultivars (Crimson and Autumn Royal) were trained on an overhead trellis system which permitted the ground cover to reach values up to 90 %. Two campaigns of mid-season measurements were performed using one of the heat pulse techniques available (that known as the T max approach). Obtained values for average seasonal daily transpiration ranged between 3.9 and 4.4 mm day?1, for both cultivars, depending on the period considered. Weekly averages of the basal crop coefficients, from mid-May to end-September, ranged from 0.47 to 0.87. A polynomial equation was fit to the measured basal crop coefficients as a function of fraction of thermal units. After further validation for other cultivars with different cumulative thermal requirements, this equation could be considered helpful for farmers as a practical estimate of the table grape basal crop coefficient under the netting. 相似文献
997.
Chemical properties and reactivity of manganese chelates and complexes in solution and soils 下载免费PDF全文
Commercial fertilizers containing synthetic manganese (Mn) chelates and complexes are currently used to alleviate Mn deficiency in crops. However, studies conducted on Mn sources in order to evaluate their behavior maintaining Mn soluble in nutrient solution and soil have not been done. In this work, representative commercial Mn fertilizers based on chelates and complexes were characterized and their chemical stability in solution and interaction with soils has been evaluated. Fertilizers studied were two ethylene diamine tetraacetic acid (EDTA) Mn chelates, one N‐(1,2‐dicarboxyethyl)‐D,L‐aspartic acid (IDHA) Mn chelate, two lignosulfonates, one carboxylate, one fulvate, one gluconate, and one heptagluconate‐based Mn complex. Characterization consisted of the determination of the soluble and chelated or complexed Mn, and the ligand identification by nuclear‐magnetic resonance (NMR). Stability study included batch experiments in Ca solution at different pH and three batch experiments with soil comparing with MnSO4. Results indicate that most of the Mn fertilizers comply with the declared “soluble and chelated or complexed” metal content. At a usual pH range of calcareous soils (7.5–8.5), both chelates and complexes maintain more Mn in solution than MnSO4 in the presence of Ca. Several factors affect the Mn remaining in solution after the interaction with the soil, especially, the soil‐to‐solution ratio. All chelates and complexes are better alternatives to the use of MnSO4 in agronomical practices such as fertigation and soil application. Mn‐IDHA as chelate and Mn‐HGl or Mn‐Carb as complexes can be efficient, economical, and environmental friendly fertilizers for foliar application and hydroponic cultures. In soil application, Mn‐EDTA or Mn‐LS would be the best options. In this case, lignosulfonic acid represents a sustainable and low‐cost solution. 相似文献
998.
Larissa Alves Guimar?es Paula Christine Jimenez Thiciana da Silva Sousa Hozana Patrícia S. Freitas Danilo Damasceno Rocha Diego Veras Wilke Jesús Martín Fernando Reyes Otília Deusdênia Loiola Pessoa Letícia Veras Costa-Lotufo 《Marine drugs》2014,12(12):5839-5855
The present study highlights the biological effects of chromomycin A2 toward metastatic melanoma cells in culture. Besides chromomycin A2, chromomycin A3 and demethylchromomycin A2 were also identified from the extract derived from Streptomyces sp., recovered from Paracuru Beach, located in the northeast region of Brazil. The cytotoxic activity of chromomycin A2 was evaluated across a panel of human tumor cell lines, which found IC50 values in the nM-range for exposures of 48 and 72 h. MALME-3M, a metastatic melanoma cell line, showed the highest sensitivity to chromomycin A2 after 48h incubation, and was chosen as a model to investigate this potent cytotoxic effect. Treatment with chromomycin A2 at 30 nM reduced cell proliferation, but had no significant effect upon cell viability. Additionally, chromomycin A2 induced accumulation of cells in G0/G1 phase of the cell cycle, with consequent reduction of S and G2/M and unbalanced expression of cyclins. Chromomycin A2 treated cells depicted several cellular fragments resembling autophagosomes and increased expression of proteins LC3-A and LC3-B. Moreover, exposure to chromomycin A2 also induced the appearance of acidic vacuolar organelles in treated cells. These features combined are suggestive of the induction of autophagy promoted by chromomycin A2, a feature not previously described for chromomycins. 相似文献
999.
Alberto J. Martín-Rodríguez Fernando Reyes Jesús Martín Juan Pérez-Yépez Milagros León-Barrios Alan Couttolenc César Espinoza ángel Trigos Víctor S. Martín Manuel Norte José J. Fernández 《Marine drugs》2014,12(11):5503-5526
In our search for quorum-sensing (QS) disrupting molecules, 75 fungal isolates were recovered from reef organisms (endophytes), saline lakes and mangrove rhizosphere. Their QS inhibitory activity was evaluated in Chromobacterium violaceum CVO26. Four strains of endophytic fungi stood out for their potent activity at concentrations from 500 to 50 μg mL−1. The molecular characterization, based on the internal transcribed spacer (ITS) region sequences (ITS1, 5.8S and ITS2) between the rRNA of 18S and 28S, identified these strains as belonging to four genera: Sarocladium (LAEE06), Fusarium (LAEE13), Epicoccum (LAEE14), and Khuskia (LAEE21). Interestingly, three came from coral species and two of them came from the same organism, the coral Diploria strigosa. Metabolic profiles obtained by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) suggest that a combination of fungal secondary metabolites and fatty acids could be the responsible for the observed activities. The LC-HRMS analysis also revealed the presence of potentially new secondary metabolites. This is, to the best of our knowledge, the first report of QS inhibition by marine endophytic fungi. 相似文献
1000.
Anna Ilyina Roberto Arredondo-Valdés Salavat Farkhutdinov Elda Patricia Segura-Ceniceros José Luis Martínez-Hernández Radik Zaynullin Rayhana Kunakova 《Plant foods for human nutrition (Dordrecht, Netherlands)》2014,69(1):65-70
In vitro effect of betulin-containing extract from Betula pendula Roth. bark on alpha-amylase activity was studied, the kinetic mechanism of interaction was proposed and in vivo effect of betulin-containing extract on weight gain and meat quality of broiler chickens was evaluated. The highest level of inhibitory activity (20 %) was detected in extract concentration of 1,000 mg/L. Increased extract concentration did not lead to increased enzyme inhibition. Using Dixon and Cornish-Bowden coordinates, the competitive mechanism of inhibition was demonstrated. Calculated kinetic parameters were: Km equal to 0.6 mg/mL, Vmax equal to 2.6 and 2.1 mM/min from Lineweaver-Burk and Dixon coordinates, respectively and Ki equal to 3,670?±?230 mg/mL. The partial inhibition of enzyme indicates the existence of low concentration of active inhibitory form, which reaches saturation level with increased extract concentration in applied suspension. Therefore, Ki has an apparent constant character. This partial inhibition of amylase activity observed in in vitro assay did not affect weight gain and meat quality of broiler chickens during in vivo assay. Rather, the tendency to increase the weight of edible parts and muscles compared to diet without additive suggests that the extract may be a potential food additive in poultry farming. Additionally, it could be a source for further pharmaceutical and pharmacological research. 相似文献