Isolation of 4-methylthio-3-butenyl glucosinolate from Raphanus sativus sprouts (kaiware daikon) and its redox properties     

Barillari J  Cervellati R  Paolini M  Tatibouët A  Rollin P  Iori R 《Journal of agricultural and food chemistry》2005,53(26):9890-9896

The most promising among glucosinolates (GLs) are those bearing in their aglycon an extra sulfur function, such as glucoraphasatin (4-methylthio-3-butenyl GL; GRH) and glucoraphenin (4-methylsulfinyl-3-butenyl GL; GRE). The GRE/GRH redox couple is typically met among secondary metabolites of Raphanus sativus L. and, whereas GRE prevails in seeds, GRH is the major GL in full-grown roots. During the 10 days of sprouting of R. sativus seeds, the GRE and GRH contents were determined according to the Eurpean Union official method (ISO 9167-1). In comparison to the seeds, the GRE content in sprouts decreased from about 90 to about 12 micromol g(-1) of dry weight (dw), whereas a 25-fold increase--from about 3 to 76 micromol g(-1) of dw--of the GRH content was measured. An efficient pure GRH gram-scale production process from R. sativus (kaiware daikon) sprouts resulted in significant yield improvement of up to 2.2% (dw basis). The reaction of GRH with both H2O2 and ABTS*+ radical cation was investigated. Whereas H2O2 oxidation of GRH readily resulted in complete transformation into GRE, ABTS*+ caused complete decay of the GL. Even though not directly related to its radical scavenging activity, the assessed reducing capacity of GRH suggests that R. sativus sprouts might possess potential for health benefits.  相似文献   

Assessment of sugar maple tree growth in relation to the partitioning of elements in xylem along a soil acidity gradient     

Simon Bilodeau-Gauthier  Daniel Houle  Christian GagnonBenoît Côté  Christian Messier 《Forest Ecology and Management》2011,261(1):95-104

Partitioning of elements in tree xylem is being increasingly studied, as it suggests that elements are potentially mobile within the xylem long after their uptake. A recent study revealed that only the most mobile xylem fraction (water-soluble) of base cations (calcium [Ca], magnesium [Mg], and potassium [K]) increased at higher soil acidity, while the two mobile fractions (water- and acid-soluble) of acidic metals—potentially phytotoxic aluminium (Al), cadmium (Cd) and manganese (Mn)—were significantly enhanced on very acid soils. The current paper presents an investigation of soil-wood chemistry relationships with basal area tree growth. It was hypothesized that the growth of sugar maple would be reduced by low base cation and high acidic metal concentrations in the xylem mobile fractions. Sugar maple trees (n = 55) from six watersheds in southern Quebec, Canada were analysed by sequential chemical extractions for the water-soluble, acid-soluble and residual fractions of base cations (Ca, K, Mg) and acidic metals (Al, Cd, Mn) in xylem. Generally, tree growth was positively correlated to concentrations of base cations in wood (ρ = 0.27-0.50) and soil (ρ = 0.41-0.67), and negatively correlated to concentrations of acidic metals in wood (ρ = −0.33 to −0.52) and soil (ρ = −0.67). However, these relations differed depending on the element fraction considered. Water- and acid-soluble xylem concentrations of base cations and Al were among the best predictors of growth trends (R² = 0.46-0.51). The relationship between acidic metals and tree growth is further discussed.  相似文献   

Embolism induced by winter drought may be critical for the survival of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. near its southern distribution limit     

José Javier Peguero-Pina  José María Alquézar-Alquézar  Stefan Mayr  Hervé Cochard  Eustaquio Gil-Pelegrín 《Annals of Forest Science》2011,68(3):565-574

Introduction   

Scots pine populations in the SE “Sistema Ibérico” range suffered a severe defoliation in the S face of the crown in isolated trees of thinned stands. This process was detected at the end of the winter 2001–2002.  相似文献   

Diversity in phosphorus mobilisation and uptake in ectomycorrhizal fungi     

Claude Plassard  Julien Louche  Muhammad A. Ali  Myriam Duchemin  Elvira Legname  Benoît Cloutier-Hurteau 《Annals of Forest Science》2011,68(1):33-43

• Introduction   

Phosphorus (P) is often the first or second element limiting aboveground net primary productivity of forests. Besides low available inorganic orthophosphate (Pi) concentrations, soil may contain high total P contents, as insoluble mineral P or as organic P. Most plants form mycorrhizal associations that improve their P nutrition. Three main hypotheses have been proposed to explain this positive effect through an increase of (1) P mobilisation from mineral P, (2) P mobilisation from organic P and (3) soil exploration and P uptake. However, the positive effect of mycorrhizal symbiosis may be variable with the fungal species forming the association. This could be due to the different abilities of mycorrhizal fungi to mobilise P and/or to take up Pi from the soil.  相似文献   

SOIL STRUCTURE IN VERTISOLS OF THE BLUE NILE CLAY PLAINS, SUDAN     

J. H. DE  VOS t. N. C. K. J. VIRGO 《European Journal of Soil Science》1969,20(1):189-206

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Porous, crystalline, covalent organic frameworks     

Côté AP  Benin AI  Ockwig NW  O'Keeffe M  Matzger AJ  Yaghi OM 《Science (New York, N.Y.)》2005,310(5751):1166-1170

Covalent organic frameworks (COFs) have been designed and successfully synthesized by condensation reactions of phenyl diboronic acid {C6H4[B(OH)2]2} and hexahydroxytriphenylene [C18H6(OH)6]. Powder x-ray diffraction studies of the highly crystalline products (C3H2BO)6.(C9H12)1 (COF-1) and C9H4BO2 (COF-5) revealed expanded porous graphitic layers that are either staggered (COF-1, P6(3)/mmc) or eclipsed (COF-5, P6/mmm). Their crystal structures are entirely held by strong bonds between B, C, and O atoms to form rigid porous architectures with pore sizes ranging from 7 to 27 angstroms. COF-1 and COF-5 exhibit high thermal stability (to temperatures up to 500 degrees to 600 degrees C), permanent porosity, and high surface areas (711 and 1590 square meters per gram, respectively).  相似文献   

β-兴奋剂在畜牧业上的应用及残留检测方法(综述)     

彭吉超  肖永祚 《四川农业大学学报》1995,13(2):195-202

本文对β－兴奋剂的化学结构、作用机理、应用情况、检测方法以及使用不当 可能产生的负作用和毒性估计作了比较详尽的综述．  相似文献   

CoRoT measures solar-like oscillations and granulation in stars hotter than the Sun     

Michel E  Baglin A  Auvergne M  Catala C  Samadi R  Baudin F  Appourchaux T  Barban C  Weiss WW  Berthomieu G  Boumier P  Dupret MA  Garcia RA  Fridlund M  Garrido R  Goupil MJ  Kjeldsen H  Lebreton Y  Mosser B  Grotsch-Noels A  Janot-Pacheco E  Provost J  Roxburgh IW  Thoul A  Toutain T  Tiphène D  Turck-Chieze S  Vauclair SD  Vauclair GP  Aerts C  Alecian G  Ballot J  Charpinet S  Hubert AM  Lignières F  Mathias P  Monteiro MJ  Neiner C  Poretti E  de Medeiros JR  Ribas I  Rieutord ML  Cortés TR  Zwintz K 《Science (New York, N.Y.)》2008,322(5901):558-560

Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars.  相似文献   

胱氨酸生产废水的效益型资源化研究     

陈玉成  蒲富永  皮广洁  叶进 《农业环境科学学报》1995,(6)

针对目前胱氨酸生产废水的处理和资源化所存在的问题，通过现场调查、室内模拟、生物试验、车间试生产等手段，探讨了胱氨酸生产废水效益型资源化的原理和技术应用，阐明了“半浓缩─脱水调制─处理改型”的技术路线将胱氨酸生产废水制成有机一无机复合型的氨基酸复合（混）固体肥料的工艺特点、产品特点和效益特点。  相似文献   

Spontaneous cortical activity reveals hallmarks of an optimal internal model of the environment     

Berkes P  Orbán G  Lengyel M  Fiser J 《Science (New York, N.Y.)》2011,331(6013):83-87

The brain maintains internal models of its environment to interpret sensory inputs and to prepare actions. Although behavioral studies have demonstrated that these internal models are optimally adapted to the statistics of the environment, the neural underpinning of this adaptation is unknown. Using a Bayesian model of sensory cortical processing, we related stimulus-evoked and spontaneous neural activities to inferences and prior expectations in an internal model and predicted that they should match if the model is statistically optimal. To test this prediction, we analyzed visual cortical activity of awake ferrets during development. Similarity between spontaneous and evoked activities increased with age and was specific to responses evoked by natural scenes. This demonstrates the progressive adaptation of internal models to the statistics of natural stimuli at the neural level.  相似文献