Organic resources and earthworms affect phosphorus availability to sorghum after phosphate rock addition in semi-arid West Africa   总被引：1，自引：0，他引：1  

Elisée Ouédraogo  Lijbert Brussaard  Abdoulaye Mando  Leo Stroosnijder 《Biology and Fertility of Soils》2005,41(6):458-465

A field experiment was laid out in Burkina Faso (West Africa) on an Eutric Cambisol to investigate the interaction of organic resource quality and phosphate rock on crop yield and to assess the contribution of earthworms (Millsonia inermis Michaelsen) to P availability after phosphate rock application. Organic resources of different quality were applied at a dose equivalent to 40 kg N ha^–1 with or without phosphate rock from Kodjari (Burkina Faso) at a dose equivalent to 25 kg P ha^–1, and were compared with control and single phosphate rock treatments in a factorial complete block design with four replicates. Sorghum (Sorghum bicolor L. Moench) variety SARIASSO 14 was grown. Sheep dung had the highest impact on earthworm casting intensity followed by maize straw. Combining organic resources with phosphate rock reduced earthworm casting activities compared to a single application of organic resources or phosphate rock. Addition of phosphate rock to maize straw reduced P availability in earthworm casts whereas combining sheep dung or compost with phosphate rock increased P availability. The contribution of earthworms to Kodjari phosphate rock solubilisation mainly occurred through their casts, as the available P content of casts was 4 times higher than that of the surrounding soil.  相似文献   

Production of bioavailable flavonoid glucosides in fruit juices and green tea by use of fungal alpha-L-rhamnosidases     

González-Barrio R  Trindade LM  Manzanares P  de Graaff LH  Tomás-Barberán FA  Espín JC 《Journal of agricultural and food chemistry》2004,52(20):6136-6142

Flavonoid glucosides have been reported to be more bioavailable than their rutinoside counterparts. The aim of this study is to describe a first step in the use of alpha-L-rhamnosidases (RhaA and RhaB) from Aspergillus aculeatus as a way to produce functional beverages based on their potentially increased flavonoid bioavailability. Blackcurrant juice (BCJ), orange juice (OJ), and green tea infusion (GT) were incubated with either RhaA or RhaB at 30 degrees C for 10 h. Aliquots of controls and enzyme-treated samples were taken at different time points and analyzed by high-performance liquid chromatography-photodiode-array detector-mass spectrometry of daughter fragments (HPLC-DAD-MS-MS). Both RhaA and RhaB selectively catalyze in situ the removal of terminal rhamnosyl groups in the three beverages despite the heterogeneity of assay conditions such as different rutinosides and pH. Incubation of the three beverages with the two rhamnosidases resulted in a hyperbolic decrease in the flavonoid rutinosides (anthocyanins in BCJ, flavanones in OJ, and flavonols in GT) and a concomitant increase in their flavonoid glucoside counterparts. The time required for conversion of 50% of the rutinoside into the corresponding flavonoid glucoside ranged from 30 min (RhaB-rutin in GT) to 6 h (RhaB-delphinidin 3-rutinoside in BCJ). The results presented in this paper are a step forward in the use of enzyme-treated beverages as a source of bioavailable flavonoid glucosides.  相似文献   

Synergistic activity of chitinases and β-1,3-glucanases enhances fungal resistance in transgenic tomato plants     

Erik Jongedijk  Henk Tigelaar  Jeroen S. C. van Roekel  Sandra A. Bres-Vloemans  Ilma Dekker  Peter J. M. van den Elzen  Ben J. C. Cornelissen  Leo S. Melchers 《Euphytica》1995,85(1-3):173-180

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Erik Jongedijk  Henk Tigelaar  Jeroen S. C. van Roekel  Sandra A. Bres-Vloemans  Ilma Dekker  Peter J. M. van den Elzen  Ben J. C. Cornelissen  Leo S. Melchers 《Euphytica》1955,85(1-3):173-180

Summary Simultaneous expression of a tobacco class I chitinase and a class I -1,3-glucanase gene in tomato resulted in increased fungal resistance, whereas transgenic tomato plants expressing either one of these genes were not protected against fungal infection. After infection with Fusarium oxysporum f.sp. lycopersici, a 36% to 58% reduction in disease severity was observed in resistant tomato lines. Two transgenic lines largely recovered from the initial infection by the time wild-type tomato plants had died.The overall results are consistent with the observation that class I chitinases and class I -1,3-glucanases synergistically inhibit the growth of fungi in vitro and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in planta.  相似文献   

Effects of tillage, organic resources and nitrogen fertiliser on soil carbon dynamics and crop nitrogen uptake in semi-arid West Africa     

Elise Oudraogo  Abdoulaye Mando  Leo Stroosnijder 《Soil & Tillage Research》2006,91(1-2):57-67

Tillage, organic resources and fertiliser effects on soil carbon (C) dynamics were investigated in 2000 and 2001 in Burkina Faso (West Africa). A split plot design with four replications was laid-out on a loamy-sand Ferric Lixisol with till and no-till as main treatments and fertiliser types as sub-treatments. Soil was fractionated physically into coarse (0.250–2 mm), medium (0.053–0.250 mm) and fine fractions (< 0.053 mm). Particulate organic carbon (POC) accounted for 47–53% of total soil organic carbon (SOC) concentration and particulate organic nitrogen (PON) for 30–37% of total soil nitrogen concentration. The POC decreased from 53% of total SOC in 2000 to 47% of total SOC in 2001. Tillage increased the contribution of POC to SOC. No-till led to the lowest loss in SOC in the fine fraction compared to tilled plots. Well-decomposed compost and single urea application in tilled as well as in no-till plots induced loss in POC. Crop N uptake was enhanced in tilled plots and may be up to 226 kg N ha⁻¹ against a maximum of 146 kg N ha⁻¹ in no-till plots. Combining crop residues and urea enhanced incorporation of new organic matter in the coarse fraction and the reduction of soil carbon mineralisation from the fine fraction. The PON and crop N uptake are strongly correlated in both till and no-till plots. Mineral-associated N is more correlated to N uptake by crop in tilled than in no-till plots. Combining recalcitrant organic resources and nitrogen fertiliser is the best option for sustaining crop production and reducing soil carbon decline in the more stabilised soil fraction in the semi-arid West Africa.  相似文献   

Revisiting the fundamentals of phosphorus fractionation of sediments and soils   总被引：1，自引：0，他引：1  

Leo M. Condron  Susan Newman 《Journal of Soils and Sediments》2011,11(5):830-840

Introduction  

Sequential fractionation procedures have been an important tool in the study of phosphorus (P) dynamics in soils and sediments for over 50 years. Throughout this period, the various methodologies have been thoroughly reviewed, and several limitations are widely acknowledged, but there are also aspects of P fractionation that have received little or no discussion. As there are few alternatives to fractionation procedures, in order to advance the usefulness of these techniques, we need to explore the undisclosed variables that may falsely bias our interpretation.  相似文献   

Cartilage thickness of the trochlea of the talus, with emphasis on sites predisposed to osteochondrosis dissecans, in clinically normal juvenile and adult dogs     

Brunnberg MM  Engelke E  Gielen IM  van Bree HJ  Hoffmann JE  Brunnberg L  Waibl HR 《American journal of veterinary research》2011,72(10):1318-1324

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Identifying risk factors of highly pathogenic avian influenza (H5N1 subtype) in Indonesia     

Loth L  Gilbert M  Wu J  Czarnecki C  Hidayat M  Xiao X 《Preventive veterinary medicine》2011,102(1):50-58

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Identification of the peroxidase-generated intermolecular dityrosine cross-link in bovine α-lactalbumin     

Heijnis WH  Dekker HL  de Koning LJ  Wierenga PA  Westphal AH  de Koster CG  Gruppen H  van Berkel WJ 《Journal of agricultural and food chemistry》2011,59(1):444-449

The peroxidase-mediated oxidation of calcium-depleted bovine α-lactalbumin generates a mixture of covalently bound protein oligomers with interesting foaming properties. Here, we isolated the initially formed covalent α-lactalbumin dimer and studied its mode of cross-linking. Liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) of proteolytic digests revealed the unambiguous identification of a peroxidase-catalyzed covalent link between Tyr18 and Tyr50. This shows that, although the radical reaction is often regarded as a random reaction, the initial product formation is specific. Protein structural modeling indicates that the conjugation reaction between these tyrosines is sterically favored and involves initial noncovalent protein complex formation through charge compensation, facilitating intermolecular cross-linking. The identification of the Tyr18-Tyr50 cross-link supports the view that the peroxidase-mediated oxidation of apo α-lactalbumin is a sequential process, involving the formation of linear trimers and higher order oligomers.  相似文献   

Erfl?rung, betressend die allgemeine National?fonomie, herausgegeben von Dr. Leo (Underlind)     

Leo Underlind 《Forstwissenschaftliches Centralblatt》1899,21(3):183-184

Ohne Zusammenfassung  相似文献