4,907 research outputs found

    Land Use Intensification Effects on Soil C Dynamics in Subtropical Grazing Land Ecosystems

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    The impacts of land intensification on carbon (C) responses are important components of soil organic carbon (SOC) management. Grazing land intensification typically involves the use of highly productive plant species that can support greater grazing pressure, removal of higher proportions of site biomass and nutrients during mechanical harvest or grazing, and increased use of fertilizers, particularly N. Current improved grazing land management strategies are aimed at increasing above-ground biomass yield, with less regard for below-ground C dynamics. Because intensive management affects above- and below-ground C inputs (Schuman et al. 1999; Liu et al. 2011a,b), it can therefore have important implications on the amount and characteristics of SOC stored in grazing lands (Franzluebbers and Stuedemann, 2003; Dubeux et al. 2006; Silveira et al. 2013). The objective of this study was to investigate the long-term impacts of converting native rangeland ecosystems into intensively managed systems on SOC dynamics in subtropical ecosystems

    Temperature Effects on Phosphorus Release from a Biosolids-Amended Soil

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    This study was designed to evaluate the effects of temperature on the potential leachable P pool and distribution of chemical P forms in a biosolids-amended soil. A P-deficient Spodosol was incubated with seven biosolids and inorganic P fertilizer at 20 and 32°C for 90 days. Amendments were applied to provide a total P concentration of 112 mg kg−1 soil, which correspond to a field application of ~224 kg P ha−1. Cumulative P mass leached during the 90 d study for any P source was <2% of the applied P, but greater cumulative P mass was released from the biological P removal and composted biosolids than from the heat-dried materials. Increasing temperature (20 to 32°C) generally decreased cumulative P mass leached, suggesting greater soil affinity to retain P at 32°C than at 20°C. In a static incubation experiment (no leaching), soil water-extractable P concentrations were reduced over time, but no temperature effect was observed. Similarly, P distribution among the various fractions was not affected by temperature. The relatively great ability of the soil to sorb P masked differences in biosolids properties and the potential impacts of temperature on P lability. Additional work using low P-sorbing soils is warranted

    Herbage Accumulation, Nutritive Value and Persistence of Mulato II in Florida

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    Grasses in the Brachiaria genus are the most widely grown forages in tropical America, occupying over 80 Mha (Boddey et al. 2004). Mulato II is apomictic and a vigorous, semi-erect cultivar resulting from 3 generations of crosses including original crosses between ruzigrass and signal-grass (cv. Basilisk, apomictic tetrapliod). According to Peters et al. (2003), Mulato produced 25% more herbage mass than palisadegrass (Brachiaria brizantha) and koroni-viagrass (Brachiaria humidicola) under similar management practices. Although Mulato II shows promise as a forage in tropical regions, herbage accumulation and persistence in subtropical areas is unknown. This publication summarises results of the research with Mulato II conducted in Florida in the last 5 years

    Determination and comparison of the chemical composition of Calendula L. species growing in Continental Portugal

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    11th National Meeting of Organic Chemistry and 4th Meeting of Therapeutic Chemistry.The flora of Continental Portugal includes three species of Calendula L. (Calendula officinalis L., C. arvensis L., C. suffruticosa Vahl), one of which comprises three subspecies (C. suffruticosa subsp. algarbiensis (Boiss.) Nyman, C. suffruticosa subsp. lusitanica (Boiss.) Ohle and C. suffruticosa subsp. cinerea (Ohle) P.Silveira & A.C.Gonç.). C. officinalis is recognised for its medical properties and its chemical composition has been widely studied (Muley, B. P., et al. J. Pharm. Res. 2009, 8, 455; Safdar, W., et al. Int. J. Cell Mol. Biol. 2010, 1, 108). Nevertheless, little is known about the chemical composition of C. arvensis and even less regarding the different subspecies of C. suffruticosa. Therefore, the present study aims the elucidation of these plants’ chemical composition and to compare and identify differences and/or similarities among them. […].Instituto da Conservação da Natureza e das Florestas; Universidade de Aveiro; FCT / MEC (FCT UID / QUI / 00062/2013); UEM CESAM (UID / AMB / 50017); FEDER (Acordo de Parceria PT2020).info:eu-repo/semantics/publishedVersio

    Pittosporum Undulatum and Hedychium Gardnerianum: nutritive value and secondary metabolites on cattle reproductive performances

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    Hedychium gardnerianum (HG) and Pittospporum undulatum (PU) are invasive plants all over the world, being in the Azores supplied to cattle on periods of shortage food. As these plants produce secondary metabolites, including a diverse range of phytochemicals compounds, the aim of the presente study is to identify how these metabolites can be related to animal’s reproductive performances. For such purpose, plants were harvested on winter, compounds extracted by method of decoction and analysed by combination of liquid chromatography and mass spectrometry as well as highperformance liquid chromatography. For nutritive evaluations, Van Soest and Weende methodologies were used. In HG quercetin-3, 4'-di-O-betaglucopyranoside, myricetin rhamnoside, quercetin rhamnoside, and gibberellin A1 and A8 were identified, while for PU were found cafeic acid derivatives, including dicaffeoylquinic acid and caffeoylquinic acid. In nutritional terms, these plants can be considered as poor, presenting percentages of dry matter (DM%) of 16.34% and 40.39%, respectively for HG and PU. Values for ash 10.4%, crude protein (CP) 7.75%, neutral detergent fiber (NDF) 64.5, acid detergent fiber (ADF) 34.69%, acid detergent lignin (ADL) 3.47% and ether extract (EE) 2.03% were found for HG. For PU values were ash 6.64%, CP 6.11%, NDF 43.84%, acid ADF 35.57%, ADL 3.56% and EE 2.71%. This study clearly indicated that, besides their low nutritive values, these plants can be used to feed ruminants, especially when pasture lacks. Nevertheless, as some compounds, namely the caffeoylquinic and dicaffeoylquinic acids, are known to be associated to physiological reproductive mechanisms, one could speculate that these compounds can be directly or indirectly associated to reproductive performances in bovine fed with these plants

    Genomic profiling of tumor initiating prostatospheres

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    <p>Abstract</p> <p>Background</p> <p>The cancer stem cell (CSC) hypothesis proposes that a population of tumor cells bearing stem cell properties is responsible for the origin and maintenance of tumors. Normal and cancer stem cells possess the ability to grow in vitro as self-renewing spheres, but the molecular basis of this phenotype remains largely unknown. We intended to establish a comprehensive culture system to grow prostatospheres (PSs) from both cancer cell lines and patient tumors. We then used gene expression microarrays to gain insight on the molecular pathways that sustain the PS tumor initiating cell (TIC) phenotype.</p> <p>Results</p> <p>Traditional stem cell medium (SCM) supplemented with Knockoutâ„¢SR (KO) allows the propagation of monoclonal PSs from cell lines and primary cells. PSs display gene expression and tumorigenicity hallmarks of TICs. Gene expression analysis defined a gene signature composed of 66 genes that characterize LNCaP and patient PSs. This set includes novel prostate TIC growth factors (NRP1, GDF1, JAG1), proteins implicated in cell adhesion and cytoskeletal maintenance, transcriptional regulators (MYCBP, MYBL1, ID1, ID3, FOS, ELF3, ELF4, KLF2, KLF5) and factors involved in protein biosynthesis and metabolism. Meta-analysis in Oncomine reveals that some of these genes correlate with prostate cancer status and/or progression. Reporter genes and inhibitors indicate that the Notch pathway contributes to prostatosphere growth.</p> <p>Conclusions</p> <p>We have developed a model for the culture of PSs, and provide a genomic profile that support CSCs identity. This signature identifies novel markers and pathways that are predicted to correlate with prostate cancer evolution.</p

    Challenges and Opportunities to Increase Carbon Sequestration in Subtropical Grazing Lands

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    Livestock production has a significant environmental footprint. However, adoption of regenerative grazing land management practices can serve as a means of producing food with lower, or even net positive environmental impacts. Globally, much of the grazing land ecosystems are degraded due to improper management. This is particularly true in the southeastern US, where extensive areas of planted pastures are degraded due to inadequate nutrient and soil management. In this presentation, we will discuss the opportunities and challenges associated with increasing soil and ecosystem C sequestration in subtropical grazing lands through regenerative management practices. Introductio

    The Use of Sunn Hemp as Forage in Florida

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    Sunn hemp (Crotalaria juncea L.) is a warm-season annual legume that has been widely used as cover crop; however, there is potential to use sunn hemp as forage in subtropical regions. The objective of this study was to evaluate management practices to improve the efficiency of using sunn hemp as a forage crop. The study was conducted in Ona, Florida, USA from 2016 to 2018 and tested the factorial arrangement of five sunn hemp genotypes (Crescent Sunn, Ubon, Blue Leaf, and AU Golden) and two harvest times (60 d after seeding or flowering) with four replicates. There was a cultivar × harvest period effect on HA, crude protein (CP), and in vitro digestible organic matter (IVDOM) concentrations. Herbage accumulation was greater at flowering than 60 d harvest for all cultivars; however, the magnitude of increase was greater for Blue Leaf and Crescent Sun than AU Golden and Ubon. AU Golden and Ubon flowered at 83 and 92 d after seeding, while Blue Leaf and Crescent Sun flowered or were harvested at 166 d after seeding. AU Golden and Crescent Sunn had the greatest CP at 60 d harvest, and Blue Leaf and Ubon had the least CP concentrations. AU Golden and Crescent Sun had the greatest IVDOM at 60-d harvest; however, AU Golden and Ubon had greater IVDOM than Blue Leaf and Crescent Sun at flowering. Sunn hemp may be a feasible warm-season annual legume to be used in forage systems in Florida and harvest 60 d after seeding would results in forage with greater nutritive value
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