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991.
In direct sowing, desiccation of the cover crops with herbicides can affect N availability in agroecosystems, reducing N use efficiency by the crop in succession. In this sense, the objective of the study was to evaluate nitrogen losses in the soil–plant system after application of the herbicides glyphosate and glufosinate-ammonium on pearl millet [Pennisetum glaucum (L.) R. Brown, var. ADR500]. Plants were grown in a sandy soil, fertilized with 15N ammonium sulfate, at N dose of 135.7 mg kg?1. After herbicide application, the N distribution within the plant was changed, with an observed N reduction in leaves and increased N in stalks. The glyphosate and glufosinate reduced, by 25 and 30%, respectively, the amount of N in plant tissues and increased by 3.0 g m?2 the losses in the soil–plant system of the N provided from the fertilizer. This information can be useful in preparing management strategies that will provide greater nitrogen fertilization effectiveness and, consequently, smaller environmental impacts from the use of nitrogen fertilizers and herbicides. 相似文献
992.
Anthocyanic vacuolar inclusions (AVIs) are intra-vacuolar structures capable of concentrating anthocyanins and are present
in over 50 of the highest anthocyanin-accumulating plant species. Presence of AVIs alters pigment intensity, total anthocyanin
levels, pigment hue and causes bathochromic shifts in a spatio-temporal manner within various flowers, vegetables and fruits.
A year-long study on Vitis vinifera cell suspension cultures found a strong correlation between AVI prevalence and anthocyanin content, but not the number of
pigmented cells, growth rate or stilbene content. Furthermore, enhancement of the prevalence of AVIs and anthocyanins was
achieved by treatment of V. vinifera cell suspension cultures with sucrose, jasmonic acid and white light. A unique autofluorescence of anthocyanins was used
to demonstrate microscopically that AVIs proceed from the cytosol across the tonoplast and were able to coalesce intravacuolarly,
with fewer, larger AVIs predominating as cells mature. Purification and characterisation of these bodies were performed, showing
that they were dense, highly organic structures, with a lipid component indicative of membrane-encasement. These purified
AVIs were also shown to comprise long-chain tannins and possessed an increased affinity for binding acylated anthocyanins,
though no unique protein component was detected. 相似文献
993.
Vicente Franco Daniel Garraín Rosario Vidal 《The International Journal of Life Cycle Assessment》2010,15(8):869-882
Background, aim and scope
Several methodological shortcomings still hinder the inclusion of transport noise as an established impact category within life cycle assessment (LCA). Earlier attempts to quantify the health damages caused by traffic noise yielded valuable results from an academic point of view, but these were of limited use in the context of everyday LCA practice. An enhanced understanding of traffic noise emission models coupled with a straightforward choice of indicators could lead to faster, more accurate assessments of health impairment due to traffic noise whose results would fittingly serve the purposes of policy makers and the information needs of the general public alike. This article aims to propose the guidelines for such assessments. 相似文献994.
Rui S. Oliveira Albina R. Franco Miroslav Vosátka Paula M. L. Castro 《Symbiosis (Philadelphia, Pa.)》2010,52(2-3):125-131
The application of ectomycorrhizal (ECM) fungi on forest nursery production is regarded as part of good management practice. However, before employing large scale inoculations in a nursery the interaction between ECM symbionts, growth substrate and fertilisation input should be studied to select the most suitable nursery practices for promoting plant growth and ECM colonisation. In this study, seedlings of Quercus ilex were inoculated with Paxillus involutus, Hebeloma mesophaeum or Cenococcum geophilum and grown in three different substrates commonly used in forest nurseries: peat-based compost, forest soil or composted pine bark. The effect of various fertilisation regimes was also studied. The choice of substrate had a significant effect on plant growth and ECM colonisation. The most appropriate combination of substrate and ECM fungus for Q. ilex growth and nutrition was peat and H. mesophaeum. Plants grown on a peat-based compost and inoculated with H. mesophaeum had a significantly greater biomass and leaf phosphorus concentration without fertilisation. Composted pine bark was found not to be suitable for growth or for mycorrhization. If the appropriate growth substrate is selected, it is possible to replace the use of chemical fertilisers by inoculation with selected ECM fungi. This results in a significant increase in plant development, and thus ECM fungi can be recommended as a more environmental friendly biotechnological approach to plant management in the nursery. 相似文献
995.
996.
997.
Franco Cataldo 《Chemistry and physics of lipids》2010,163(6):524-529
Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C60 was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C60 which is converted to an epoxide C60O. Thus, fullerene C60 displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C60 in ethyl oleate has been compared with that of the known antioxidant TMPPD (N,N′,N,N,′-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C60 in lipids has been proposed. The kinetics of C60 oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C60 photo-oxidation in lipids have been identified. 相似文献
998.
R. S. Peixoto G. M. Chaer N. Franco F. B. Reis Junior I. C. Mendes A. S. Rosado 《Antonie van Leeuwenhoek》2010,98(3):403-413
The bacterial community structures (BCSs) of Cerrado soils cultivated under conventional tillage (CT), no-tillage (NT) and
under native Cerrado (NC) vegetation were evaluated using PCR/DGGE of bacterial 16S rRNA (rrs) and rpoB genes and of Pseudomonas group genes. Soil chemical analysis, microbial biomass and the enzyme activities were also evaluated and correlated with
the BCS measurements. The multivariate ordinations of DGGE profiles showed differences between the BCS of the NC area and
those from cultivated areas. The BCSs of the CT and NT areas also differed in all DGGE fingerprints, including changes in
the profile of Pseudomonas populations, indicating that agricultural systems can also be responsible for changes within specific microbial niches, although
the clearest differences were found in the rpoB profiles. The MRPP analysis demonstrated significant differences between the BCSs from different soil layers of NT areas
based on all gene fingerprints and those of NC areas based on bacterial 16S rRNA and rpoB genes fingerprints. No differences were observed in the microbial fingerprints of CT samples from different depths, indicating
that ploughing affected the original BCS stratification. The BCS from NC areas, based on all gene fingerprints, could be related
to higher levels of soil acidity and higher amounts of MBC and of phosphatase activity. In contrast, the BCSs from cultivated
areas were related to higher levels of Ca + Mg, P and K, likely as a result of a history of chemical fertilisation in these
areas. The relationships between rpoB and Pseudomonas BCSs and all chemical and biochemical properties of soils were significant, according to a Mantel test (P < 0.05), indicating that the different changes in soil properties induced by soil use or management may drive the formation
of the soil BCS. 相似文献
999.
1000.
Yaroslav Sydorskyy Tharan Srikumar Stanley M. Jeram Sarah Wheaton Franco J. Vizeacoumar Taras Makhnevych Yolanda T. Chong Anne-Claude Gingras Brian Raught 《Molecular and cellular biology》2010,30(18):4452-4462
The small ubiquitin-related modifiers (SUMOs) are evolutionarily conserved polypeptides that are covalently conjugated to protein targets to modulate their subcellular localization, half-life, or activity. Steady-state SUMO conjugation levels increase in response to many different types of environmental stresses, but how the SUMO system is regulated in response to these insults is not well understood. Here, we characterize a novel mode of SUMO system control: in response to elevated alcohol levels, the Saccharomyces cerevisiae SUMO protease Ulp1 is disengaged from its usual location at the nuclear pore complex (NPC) and sequestered in the nucleolus. We further show that the Ulp1 region previously demonstrated to interact with the karyopherins Kap95 and Kap60 (amino acids 150 to 340) is necessary and sufficient for nucleolar targeting and that enforced sequestration of Ulp1 in the nucleolus significantly increases steady-state SUMO conjugate levels, even in the absence of alcohol. We have thus characterized a novel mechanism of SUMO system control in which the balance between SUMO-conjugating and -deconjugating activities at the NPC is altered in response to stress via relocalization of a SUMO-deconjugating enzyme.The small ubiquitin-related modifiers (SUMOs) are a family of evolutionarily conserved polypeptides that are conjugated to protein targets via the concerted action of SUMO-specific E1 (activation), E2 (conjugation), and E3 (ligase) enzymes to effect changes in subcellular localization, half-life, or target activity. A family of SUMO-specific proteases act to remove the modifier from conjugates (8, 20). The SUMO system has been implicated in a variety of critical cellular functions, such as DNA repair and replication, RNA metabolism, and stress responses (8, 16, 20). Importantly, the SUMO system is highly dynamic and the SUMO pathway enzymes appear to work together to precisely control SUMO conjugate levels in the cell (8, 16, 20). However, how the SUMO system itself is regulated is poorly understood.Localization of the SUMO pathway enzymes may play an important role in SUMO system function (21). For example, the budding yeast SUMO protease Ulp1 is tethered to the nuclear face of the nuclear pore complex (NPC) via an unconventional interaction with the karyopherin Kap121 and the heterodimeric Kap95/Kap60 complex (12, 13, 23). However, this SUMO protease is not maintained exclusively at the NPC but appears to be mobile, effecting desumoylation at diverse subcellular locations: e.g., during mitosis, Saccharomyces cerevisiae Ulp1 is recruited to the septin ring to desumoylate septins (15), Schizosaccharomyces pombe Ulp1 localization is regulated throughout the cell cycle (31), and a mammalian Ulp1 homolog, SENP2, is shuttled between the nucleus and the cytoplasm (7). Consistent with these observations, SUMO conjugate levels are significantly altered in yeast strains expressing mislocalized Ulp1 (13, 37).Dramatic changes in SUMO conjugate populations have been noted in response to many different types of stresses in yeasts, mammals, and plants (9, 17, 27, 32, 38). For example, in S. cerevisiae, significantly increased steady-state SUMO conjugate levels are observed in response to elevated concentrations of ethanol (38). To better understand how the SUMO system is regulated in response to stress, we utilized alcohol as a model of a physiologically relevant stressor in yeast. Here, we demonstrate that alcohol stress results in a rapid, reversible nucleolar sequestration of Ulp1 and that enforced localization of Ulp1 in the nucleolus leads to a dramatic increase in steady-state SUMO conjugate levels. This is the first demonstration of regulated modulation of the intracellular localization of a SUMO enzyme in response to stress and thus represents a novel mechanism for SUMO system control. 相似文献