Purification and characterization of a latent polyphenol oxidase from beet root (Beta vulgaris L.)     

Gandía-Herrero F  García-Carmona F  Escribano J 《Journal of agricultural and food chemistry》2004,52(3):609-615

Polyphenol oxidase (PPO) has been extracted from beet root, in both soluble and membrane fractions. In both cases, the enzyme was in its latent state, and it was activated by sodium dodecyl sulfate. PPO was purified to apparent homogeneity. The soluble PPO purification was achieved by hydrophobic interaction chromatography and gel filtration chromatography, with apparent molecular mass of 55 kDa. The membrane PPO purification was achieved by anion exchange chromatography and gel filtration with apparent molecular mass of 54 kDa. A totally denaturing SDS-PAGE indicated the presence of a single polypeptide with an apparent molecular mass of 60 kDa for both fractions, with the band also revealed by Western blot. A partially denaturing SDS-PAGE stained a single active 36 kDa band for both fractions. Under native isoelectric focusing, a major acidic band of pH 5.2 was detected in both fractions. Kinetic characterization of PPO on the natural substrate l-dopa was carried out.  相似文献   

Genetic diversity and conservation of two endangered eggplant relatives (<Emphasis Type="Italic">Solanum vespertilio</Emphasis> Aiton and <Emphasis Type="Italic">Solanum lidii</Emphasis> Sunding) endemic to the Canary Islands     

Jaime Prohens  Gregory J. Anderson  F. Javier Herraiz  Gabriel Bernardello  Arnoldo Santos-Guerra  Daniel Crawford  Fernando Nuez 《Genetic Resources and Crop Evolution》2007,54(3):451-464

Solanum vespertilio Aiton and Solanum lidii Sunding are endemic, endangered wild species from the Canary Islands. These species are of potential value for eggplant (S. melongena) breeding, given that they are part of the secondary genepool of this crop. We study genetic diversity with amplified fragment length polymorphisms (AFLPs) markers from 5 populations of S. vespertilio (47 samples) and 3 of S. lidii (26 samples). Five related African species (S. dasyphyllum Schumach. et Thonn., S. delagoense Dunal, S. campylacanthum Hochst., S. panduriforme E. Mey, S. aff. violaceum Ortega) were also included in the analysis. A total of 235 AFLP markers included 178 and 156 that were polymorphic in S. vespertilio and S. lidii, respectively. Analysis of genetic distance, phenograms, and principal component plots showed that these rare Canarian species are differentiated (G _ST = 0.412) from the continental materials and that Solanum vespertilio is more distinct to its African congeners than is S. lidii. There is a relatively high level of differentiation between the two species (G _ST = 0.373), that presumably reflects geographic restrictions (S. lidii to Gran Canaria; S. vespertilio essentially to Tenerife). However, both species have similar levels of total diversity. We speculate that the combination of the many unusual reproductive features (andromonoecy, zygomorphy, heteranthery and weak enantiostyly in S. vespertilio) help explain genetic diversity that is high for self compatible species. The high genetic diversity may also indicate populations were larger in the past. A decrease in population size could contribute to the relatively low genetic differentiation among the populations. The data presented herein provide the foundation for initiation of ex situ and in situ conservation programs for these wild relatives of eggplant. This paper is dedicated to the memory of Dr. Richard N. Lester, who made significant contributions to the taxonomy, biosystematics and conservation of genetic resources of African species of Solanum.  相似文献   

Volatile composition of coffee berries at different stages of ripeness and their possible attraction to the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae)     

Ortiz A  Ortiz A  Vega FE  Posada F 《Journal of agricultural and food chemistry》2004,52(19):5914-5918

The analysis of volatile emissions of coffee berries in different physiological states of ripeness was performed using dynamic headspace and gas chromatography/mass spectrometry analysis for Coffea arabica, var. Colombia. The composition of the volatiles emitted by coffee berries is dominated by very high levels of alcohols, mainly ethanol, in all stages of ripeness in comparison with other compounds. Overripe coffee berries have high volatile emissions and show a composition dominated mainly by esters followed by alcohols, ketones, and aldehydes. The lowest level compounds were monoterpenes. 2-Methyl furan was detected in various ripening stages; this compound has not been previously reported as a coffee berry volatile. The presence of ethanol and other alcohols in the volatile composition might explain the effectiveness of using traps with mixed alcohols for detection and capture of coffee berry borers.  相似文献   

A two-year experience on 15N-urea fertilization of a corn field amended with fly ash     

Stefano Cervelli  Fernando di Giovanni  Amalia Perna  Gianniantonio Petruzzelli 《Water, air, and soil pollution》1989,45(1-2):173-181

Soybean seedlings (Glycine max) were exposed to simulated acid rain containing sulfate ion only or a mixture of sulfate, nitrate and chloride anions, using a continuous rain generating system in a side opened glasshouse. Plants were subjected to acid rain treatment twice a week, for a 1 or 3 hr period at a rate of 2.2 or 5.0 mm hr^?1, respectively. Dry seed yield in plants treated with simulated acid rain at pH 2.0, in the three of 4 experiments conducted over a 3 yr period, was significantly less than that at pH 3.0 or higher. Simulated acid rain treatment at pH 3.0 or higher did not significantly affect yield compared to pH 5.6; however, plants exposed to simulated acid rain at pH 4.0 tended to yield more than those treated with pH 5.6 rain. Based on the current 3 years of research in which results from 4 experiments were combined, rain acidity at current levels in Japan would not directly affect seed production of selected cultivars of soybean.  相似文献   

Zooflagellates in an anaerobic waste stabilization pond system in Mexico     

Fermín Rivera  Alfonso Lugo  Jesús Ponce  Fernando Lares  Ricardo Ortiz 《Water, air, and soil pollution》1986,27(1-2):199-214

A protozoological survey was performed on waste stabilization lagoons to isolate, identify, and determine the incidence of zooflagellates present in these waters. A correlation between the species found and the physicochemical parameters determined was also done. Fifteen samplings were analyzed from June 1981 to April 1982. Free-living zooflagellates included: Bodo edax Klebs: Bodo caudatus Dujardin;Trepomonas agilis Dujardin;Pleuromonas jaculans Perty (all of them polisaprobic indicators);Bodo saltans Ehrenberg (a mesosaprobic indicator); and Bodomorpha minima Hollande. A human commensal species Enteromonas hominis Da — Fonseca, was also isolated. The performance of the lagoons was predominantly anaerobic. The temperature seemed to be the most influential factor on the incidence of the zooflagellates isolated, especially in winter time.  相似文献   

Response of sugarcane ratoon to nitrogen without and with the application of silicon     

Bernardo Melo Montes Nogueira Borges  Thiago Batista Firmato De Almeida  Renato De Mello Prado 《Journal of plant nutrition》2016,39(6):793-803

The objective was to evaluate the effect of nitrogen, associated to silicon, on soil chemical properties, nutritional status and yield of the second sugarcane ratoon. The experiment was carried out at a Haplustox, loamy texture. The treatments consisted of urea rates of 0, 40, 80, 120 and 160 kg ha^?1 and two sources of correctives: silicate and lime. The use of nitrogen (N) associated with silicate and lime did not affect soil fertility; however, the use of silicate increased soil silicon content at harvest. Growth variables were not affected by the application of the treatments, except stalk number at harvest, which increased in the presence of silicon. N rates and the correctives did not affect the crop nutritional status, but affected the N and Si accumulation in the plant. The N rates increased the sugarcane ratoon yield regardless the use of silicate; however, they did not affect its technological quality.  相似文献   

N-mineralization in polyphenol-rich plant residues and their effect on nitrification of applied ammonium sulphate     

K. Sivapalan  V. Fernando  M.W. Thenabadu 《Soil biology & biochemistry》1985,17(4):547-551

Soil was incubated under greenhouse conditions with plant residues having varying phenolic and nitrogen contents. The total plant material added in staggered applications every 4 months was 15 g kg^?1 soil and the total incubation period was 12 months.The N-mineralization in these plant residues as influenced by their phenol and N contents was examined. The nitrification of applied (NH₄)₂SO₄ in these amended soils was also investigated under optimum conditions of pH.A high plant-N content resulted in increased N-mineralization of plant residue, but this effect was lowered by the presence of high concentrations of polyphenols in the decomposing residue, most probably due to increased participation of N with polyphenols in the formation of humus fractions.Soils amended with phenol-rich residues did not show any inhibition of nitrification of applied (NH₄)₂SO₄. Possible reasons are discussed. In organic matter decomposition, the quality of the leaf polyphenols appears to determine the degree of inhibition to soil nitrification.  相似文献   

Comparison of the ammonium acetate,Mehlich 3, and sodium tetraphenylboron as extractants to evaluate crop available potassium     

Marcelo G. Ferrando  Mónica M. Barbazán  Fernando O. García  Antonio P. Mallarino 《Communications in Soil Science and Plant Analysis》2020,51(8):997-1005

ABSTRACT

The 1 M ammonium acetate (NH₄OAc) (AA) is the most widely used method for soil-test potassium (K), but other methods have been also suggested to estimate crop available K. The accuracy of these extractants may be influenced by soil texture and clay mineralogy. This study evaluated the relationships among AA, Mehlich-3 (M3), and sodium tetraphenylboron (TPhB) methods using soils differing in texture and clay minerals from the agricultural area of Uruguay. The M3 and AA extractable K concentrations were highly correlated (R² > 0.97) across soils, although AA extracted slightly higher amount of K than M3. The TPhB method extracted more K than AA and M3, indicating that extracted K from different pools. The slopes of the relationships between TPhB and AA or M3 varied among soils being higher in fine-textured and illitic soils than in coarse soils. These results would be useful for evaluating the feasibility of incorporating M3 into a test program using the existing calibrations of the AA method. In addition, TPhB could be considered a complementary tool to improve the interpretations of the extractants to estimate soil-test K along with other characteristics such as the texture and clay mineralogy.  相似文献   

Soil macropore dynamics affected by tillage and irrigation for a silty loam alluvial soil in southern Portugal   总被引：5，自引：0，他引：5  

M. R. Cameira  R. M. Fernando  L. S. Pereira 《Soil & Tillage Research》2003,70(2):131-140

Soil tillage can have a significant effect on soil porosity and water infiltration. This study reports field measurements of near saturated hydraulic conductivity in an undisturbed soil under two tillage treatments, conventional tillage (CT) and minimum tillage (MT). The objective was to determine effective macro and mesoporosities, porosity dynamics during the irrigation season, and their contribution to water flow. Field observations were performed during the 1998 maize (Zea mays L.) cropping season in an Eutric Fluvisol with a silty loam texture, located in the Sorraia River Watershed in the south of Portugal. Infiltration measurements were done with a tension infiltrometer. At each location an infiltration sequence was performed corresponding to water tensions (φ) of 0, 3, 6 and 15 cm. Five sets of infiltration measurements were taken in both treatments in the top soil layer between May and September. One set of measurements was done at the depth of 30 cm at the bottom of the plowed layer in the CT plot. After 5 years of continuous tillage treatments the results show that regardless of the tillage treatment, saturated conductivity values K(φ₀) were several times larger than near saturation conductivity K(φ₃). This indicates that subsurface networks of water conducting soil pores can exist in both CT and MT maize production systems. In CT, the moldboard plow created macro and mesoporosity in the top soil layer while breaking pore continuity at 30 cm depth. This porosity was partially disrupted by the first irrigation, resulting in a significant decrease of 45% in the macropore contribution to flow. Later in the season, the irrigation effect was overlaid by the root development effect creating new channels or continuity between existing pores. In MT macroporosity contribution to flow did not show significant differences in time, representing 85% of the total flow. In both the treatments, macropores were the main contributing pores to the total flow, in spite of the very low macroporosity volumes.  相似文献   

Anatomy and cell wall polysaccharides of almond (Prunus dulcis D. A. Webb) seeds     

Dourado F  Barros A  Mota M  Coimbra MA  Gama FM 《Journal of agricultural and food chemistry》2004,52(5):1364-1370

The anatomy of Prunus dulcis was analyzed by applying several differential staining techniques and light microscopy. Prunus dulcis seed has a thin and structurally complex seed coat, with lignified cellulosic tissue. The embryo has two voluminous cotyledons. Cotyledon cells have a high number of protein and lipid bodies, some of which have phytin. The provascular tissue, located in the cotyledons, is oriented in small bundles perpendicular to the transverse embryonic axis. Prunus dulcis cell wall material is very rich in arabinose (45 mol %). Glucose (23%), uronic acids (12%), and xylose (12%) are also major sugar components. The polymers obtained from the imidazole and Na(2)CO(3) extracts contain mainly pectic substances rich in arabinose, but the sugar content of these extracts was very low. The majority of the pectic substances (also rich in arabinose) was recovered with the KOH extracts. These extracts, with high sugar content, yielded also xyloglucans and acidic xylans. The 4 M KOH + H(3)BO(3) extracts yielded polysaccharides rich in uronic acids and xylose and very rich in arabinose, accounting for 27% of the cell wall material.  相似文献