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排序方式: 共有1093条查询结果,搜索用时 13 毫秒
131.
In search of a maize ideotype for cell wall enzymatic degradability using histological and biochemical lignin characterization 总被引:1,自引:0,他引:1
Méchin V Argillier O Rocher F Hébert Y Mila I Pollet B Barriére Y Lapierre C 《Journal of agricultural and food chemistry》2005,53(15):5872-5881
Grass cell wall degradability is conventionally related to the lignin content and to the ferulic-mediated cross-linking of lignins to polysaccharides. To better understand the variations in degradability, 22 maize inbred lines were subjected to image analyses of Fasga- and M?ule-stained stem sections and to chemical analyses of lignins and p-hydroxycinnamic acids. For the first time, the nearness of biochemical and histological estimates of lignin levels was established. Combination of histological and biochemical traits could explain 89% of the variations for cell wall degradability and define a maize ideotype for cell wall degradability. In addition to a reduced lignin level, such an ideotype would contain lignins richer in syringyl than in guaiacyl units and preferentially localized in the cortical region rather than in the pith. Such enrichment in syringyl units would favor wall degradability in grasses, contrary to dicots, and could be related to the fact that grass syringyl units are noticeably p-coumaroylated. This might affect the interaction capabilities of lignins and polysaccharides. 相似文献
132.
Carvalho E Mateus N Plet B Pianet I Dufourc E De Freitas V 《Journal of agricultural and food chemistry》2006,54(23):8936-8944
Alpha-amylase, a major human salivary protein, and IB8c, a representative of the proline-rich proteins, were obtained by isolation from saliva and by solid-phase synthesis, respectively. The interactions between these proteins and condensed tannins isolated from grape seeds were studied at different protein and tannin concentrations by measuring their aggregation. Pectic polysaccharides were isolated from wine, and their effect on protein tannin aggregation was assessed. The results presented in this study showed that the most acidic fractions of arabinogalactan proteins have the ability to inhibit the formation of aggregates between the grape seed tannins and the two different salivary proteins. Rhamnogalacturonan II has the same ability toward alpha-amylase but not IB8c under the conditions of the present study. Polysaccharides show effects at concentrations at which they are present in wine, which could mean an influence in wine astringency. The interaction between condensed tannins and alpha-amylase is differently affected by ionic strength when compared with IB8c. 相似文献
133.
Stefanov I Baeten V Abbas O Colman E Vlaeminck B De Baets B Fievez V 《Journal of agricultural and food chemistry》2011,59(24):12771-12783
The feasibility of Raman spectroscopy in combination with partial least-squares (PLS) regression for the determination of individual or grouped trans-monounsaturated fatty acids (trans-MUFA) and conjugated linoleic acids (CLA) in milk fat is demonstrated using spectra obtained at two temperature conditions: room temperature and after freezing at -80 °C. The PLS results displayed capability for direct semiroutine quantification of several individual CLA (cis-9,trans-11 and trans-10,cis-12 C18:2) and trans-MUFA (trans-4-15 C18:1) in minor concentrations (below 1.0 g/100 g of milk fat). Calibration models were based on reference data cross-correlation or determined by specific scattering signals in the Raman spectra. Distinct bands for trans-MUFA (1674 cm(-1)) and CLA (1653 cm(-1)) from the trans isolated and cis,trans conjugated C ═ C bonds were identified, as well as original evidence for the temperature effect (new bands, peak shifts, and higher intensities) on the Raman spectra of fatty acid methyl ester and triacylglyceride standards, are supplied. 相似文献
134.
Aurlie Vinet Claire Bouyer Lionel Forestier Ahmad Oulmouden Vronique Blanquet Brigitte Picard Isabelle Cassar-Malek Muriel Bonnet Dominique Rocha Gilles Renand 《Journal of animal science》2021,99(2)
The mutation T3811 → G3811 (TG3811) discovered in the myostatin gene of the Blonde d’Aquitaine breed is suspected of contributing to the outstanding muscularity of this breed. An experiment was designed to estimate the effect of this mutation in an F2 and back-cross Blonde d’Aquitaine × Holstein population. By genotyping all known mutations in the myostatin gene, it was ensured that the TG3811 mutation was indeed the only known mutation segregating in this population. Fifty-six calves (43 F2, 13 back-cross) were intensively fattened and slaughtered at 24.0 ± 1.4 wk of age. The effects of the mutation were estimated by comparing the calves with the [T/T] (n = 18), [T/G] (n = 30), and [G/G] (n = 8) genotypes. Highly significant substitution effects (P < 0.001), above + 1.2 phenotypic SD, were shown on carcass yield and muscularity scores. Birth weight (P < 0.001) was positively affected by the mutation (+0.8 SD) but not growth rate (P = 0.97), while carcass length (P = 0.03), and fatness (P ≤ 0.03) were negatively affected (–0.5 to –0.7 SD). The characteristics of the Triceps brachii muscle were affected by the mutation (P < 0.001), with lower ICDH activity (oxidative) and a higher proportion of myosin type 2X muscle fibers (fast twitch). The effects of the TG3811 mutation were similar to those of other known myostatin mutations, although the Blonde d’Aquitaine animals, which are predominantly [G/G] homozygous, do not exhibit extreme double muscling. 相似文献
135.
Esther Sanyé-Mengual Isabelle Anguelovski Jordi Oliver-Solà Juan Ignacio Montero Joan Rieradevall 《Agriculture and Human Values》2016,33(1):101-120
Urban agriculture (UA) is spreading within the Global North, largely for food production, ranging from household individual gardens to community gardens that boost neighborhood regeneration. Additionally, UA is also being integrated into buildings, such as urban rooftop farming (URF). Some URF experiences succeed in North America both as private and community initiatives. To date, little attention has been paid to how stakeholders perceive UA and URF in the Mediterranean or to the role of food production in these initiatives. This study examines the promotion and inclusion of new forms of UA through the practice of URF and contributes to the nascent literature on the stakeholder and public perceptions of UA. It seeks to understand how those perceptions shape the development of new urban agriculture practices and projects. Barcelona (Spain) was used as a Mediterranean case study where UA and URF projects are growing in popularity. Through semi-structured interviews with 25 core stakeholders, we show that UA is largely perceived as a social activity rather than a food production initiative, because the planning of urban gardens in Barcelona was traditionally done to achieve leisure and other social goals. However, several stakeholders highlighted the potential to increase urban fertility through URF by occupying currently unused spaces. As a result, the positive valuation of URF depends on the conceptualization of UA as a social or food production activity. In turn, such conceptualization shapes barriers and opportunities for the development of URF. While most UA-related stakeholders (e.g., food co-ops, NGOs) preferred soil-based UA, newer stakeholders (e.g., architects) highlighted the economic, social and environmental opportunities of local and efficient food production through innovative URF. 相似文献
136.
Vincent Gagnon Gabriel Maltais-Landry Jaume Puigagut Florent Chazarenc Jacques Brisson 《Water, air, and soil pollution》2010,212(1-4):483-490
Hydroponics culture generates large amounts of wastewater that are highly concentrated in nitrate and phosphorus but contains almost no organic carbon. Constructed wetlands (CWs) have been proposed to treat this type of effluent, but little is known about the performance of these systems in treating hydroponic wastewater. In addition, obtaining satisfactory winter performances from CWs operated in cold climates remains a challenge, as biological pathways are often slowed down or inhibited. The main objective of this study was to assess the effect of plant species (Typha sp., Phragmites australis, and Phalaris arundinacea) and the addition of organic carbon on nutrient removal in winter. The experimental setup consisted of 16 subsurface flow CW mesocosms (1 m2, HRT of 3 days) fed with 30 L?d1 of synthetic hydroponics wastewater, with half of the mesocosms fed with an additional source of organic carbon (sucrose). Carbon addition had a significant impact on nitrate and phosphate removal, with removal means of 4.9 g m-2?d-1 of NO3-N and 0.5 g m-2 d-1 of PO4-P. Planted mesocosms were generally more efficient than unplanted controls. Furthermore, we found significant differences among plant treatments for NO3-N (highest removal with P. arundinacea) and COD (highest removal with P. australis/Typha sp.). Overall, planted wetlands with added organic carbon represent the best combination to treat hydroponics wastewater during the winter. 相似文献
137.
目前,良好的清洗和消毒被广泛地认为是孵化场优化1日龄苗鸡(Day Old Chick,DOC)生产的一种措施.良好的种蛋卫生已证明可提高DOC的存活率和质量.事实上,细菌通过蛋壳侵入种蛋的强穿透能力会影响孵化质量的诸多方面,如早期胚胎死亡率、蛋黄感染、出壳前的DOC死亡率,除此之外还有第1周中苗鸡极高的死亡率和不均匀性. 相似文献
138.
Valentová K Truong NT Moncion A de Waziers I Ulrichová J 《Journal of agricultural and food chemistry》2007,55(19):7726-7731
Diabetes and its complications, including oxidative stress, are major reasons for medical intervention and one of the most frequent causes of death in developed countries. Several lines of data suggest that the use of certain dietary polyphenolic compounds may alter glucose metabolism, thus decreasing the risk for type 2 diabetes. In this paper, we present the effect of phenolic acids (caffeic, chlorogenic, rosmarinic, and ferulic) and extracts from Smallanthus sonchifolius and Prunella vulgaris on glucose production in rat hepatocytes and on glucokinase, glucose-6-phosphatase, and phosphoenol-pyruvate carboxykinase mRNA expression in rat hepatoma Fao cells. The phenolics at 500 microM and after 1 h incubation lowered glucose production via both gluconeogenesis (10 mM alanine or dihydroxyacetone as precursors) and glycogenolysis compared with metformin. Most of the phenolics increased the level of glucokinase mRNA after 24 h in the same way as insulin (10(-7) M). 相似文献
139.
Schmidt I Renard D Rondeau D Richomme P Popineau Y Axelos MA 《Journal of agricultural and food chemistry》2004,52(19):5995-6001
Chromatographic, chemical, and spectroscopic techniques were used to characterize the physicochemical properties of napin purified by preparative chromatography. The molar extinction coefficient was determined (epsilon = 0.56), and static and dynamic light scattering measurements enabled the average molecular weight (M(w) = 13919), the second virial coefficient (A(2) = 23.95 x 10(-)(5) mol cm(3) g(-)(2)), and the hydrodynamic radius (R(H) = 1.98 nm) to be determined. No conformational changes were observed by fluorescence and circular dichroism measurements in different buffers at pH 3, 4.6, 7, and 12, confirming the high pH stability of this protein. From MALDI-TOF analysis and after enzymatic digestion, it was found that this purified sample, extracted from the rapeseed variety Express, contained mainly isoform 2SS3_BRANA. 相似文献
140.