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Ben P. Werling Timothy L. Dickson Rufus Isaacs Hannah Gaines Claudio Gratton Katherine L. Gross Heidi Liere Carolyn M. Malmstrom Timothy D. Meehan Leilei Ruan Bruce A. Robertson G. Philip Robertson Thomas M. Schmidt Abbie C. Schrotenboer Tracy K. Teal Julianna K. Wilson Douglas A. Landis 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(4):1652-1657
Agriculture is being challenged to provide food, and increasingly fuel, for an expanding global population. Producing bioenergy crops on marginal lands—farmland suboptimal for food crops—could help meet energy goals while minimizing competition with food production. However, the ecological costs and benefits of growing bioenergy feedstocks—primarily annual grain crops—on marginal lands have been questioned. Here we show that perennial bioenergy crops provide an alternative to annual grains that increases biodiversity of multiple taxa and sustain a variety of ecosystem functions, promoting the creation of multifunctional agricultural landscapes. We found that switchgrass and prairie plantings harbored significantly greater plant, methanotrophic bacteria, arthropod, and bird diversity than maize. Although biomass production was greater in maize, all other ecosystem services, including methane consumption, pest suppression, pollination, and conservation of grassland birds, were higher in perennial grasslands. Moreover, we found that the linkage between biodiversity and ecosystem services is dependent not only on the choice of bioenergy crop but also on its location relative to other habitats, with local landscape context as important as crop choice in determining provision of some services. Our study suggests that bioenergy policy that supports coordinated land use can diversify agricultural landscapes and sustain multiple critical ecosystem services.In agricultural landscapes, balancing the provisioning of food and energy with maintenance of biodiversity and ecosystem functions is a global challenge. To avoid impacts on food production, attention is increasingly being focused on the potential for marginal lands to support bioenergy production (1). Marginal lands, those suboptimal for food production, may consist of relatively small areas within generally productive landscapes or larger regions where conditions generally limit crop productivity. However, there is increasing recognition that these lands are already performing a variety of useful functions, and their conversion to bioenergy cropping could reduce these services. For example, in the north central United States, rising commodity prices are predicted to bring marginal croplands—including Conservation Reserve Program lands—into annual crop production with negative impacts on wildlife habitat and water quality (2, 3). With 2013 corn plantings at recent record highs (4) and new reports of grassland and wetland conversion to cropland (5, 6), this may be occurring already.An alternative to annual cropping is conversion of marginal croplands to perennial, cellulosic crops for bioenergy. Although current US biofuel production centers on grain ethanol derived from annual monocultures of maize (Zea mays), this situation could change with full implementation of the 2007 US Energy Independence and Security Act (7), which calls for increased production of cellulosic biofuels. In the Midwest United States, perennial grasses and forbs grown on marginal lands could provide up to 25% of national targets for cellulosic biofuel, with substantial greenhouse gas (GHG) benefits (8). Moreover, increasing the area of perennial cover on the landscape is predicted to positively affect a diverse array of organisms and ecological functions (9–11), leading to important synergies that have not yet informed the ongoing bioenergy debate. Here we provide the most comprehensive empirical evaluation of this hypothesis to date, reporting data that elucidate the impacts of different bioenergy cropping systems on a wide variety of organisms and the ecosystem functions they perform.Previous studies have examined the ability of select bioenergy crops to support specific taxa (12) or individual services such as energy production (13) or GHG mitigation (14), without consideration of the tradeoffs or synergies that can arise when considering entire suites of organisms and ecosystem functions. We report on a unique multidisciplinary study of matched sets of organisms and ecosystem services and show that perennial grass energy crops (switchgrass, Panicum virgatum, and mixed prairie plantings) synergistically enhance diversity of a variety of organisms and levels of the services they provide. We further quantify the importance of landscape context on service provisioning, suggesting that policy supporting intentional design of bioenergy landscapes could increase sustainability of both food and energy production. 相似文献
74.
Q Yan RJ Carmody Z Qu Q Ruan J Jager SE Mullican MA Lazar YH Chen 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(35):14140-14145
Sustained Toll-like receptor (TLR) stimulation continuously activates antimicrobial genes but paradoxically represses inflammatory genes. This phenomenon, termed TLR tolerance, is essential for preventing fatal inflammatory conditions such as sepsis, but its underlying mechanisms are unclear. We report here that NF-κB binding nucleic acids of gene promoters are tolerogenic motifs, which selectively recruit an NcoR-Hdac3-deacetylated-p50 repressosome to inflammatory genes. Genome-wide analyses of TLR4-induced genes revealed that NF-κB motifs were the only regulatory elements significantly enriched in tolerizable genes. Mutating the NF-κB motifs of tolerizable genes converted them into nontolerizable ones, whereas inserting NF-κB binding motifs into nontolerizable genes conferred the tolerance. Although NF-κB p50 was essential for assembling the repressosome, genetic disruption of the NcoR-Hdac3 interaction alone was sufficient to completely abolish TLR4 tolerance and to render mice vulnerable to sepsis. Thus, the specificity of TLR tolerance is dictated by evolutionally conserved nucleic acid motifs that bound by NF-κB and the NcoR repressosome. 相似文献
75.
Evidence is increasing suggesting that adding progestogens to estrogens can increase the risk of breast cancer. However, our experimental data as a result of scientific collaboration between university of Tuebingen, Germany, and university of Beijing, China, comparing all available progestogens used in hormone therapy and hormonal contraception present high evidence that there may be differences regarding breast cancer risk. Especially of concern may be to differentiate between primary and secondary risk i.e. between the effect of on benign and malignant breast epithelial cells suggesting differences in primary risk and risk in patients after breast cancer. Of importance also is that in contrast to natural progesterone the apocrine impact of stromal growth factors and also certain cell components of breast epithelial cells can strongly increase proliferation rates of some (but not all. synthetic progestogens which can lead to clinical cancer before (in contrast to estrogen-only therapy. carcinoprotective mechanisms can work. Regarding clinical data, epidemiological studies and especially the Women's Health Initiative, so far the only prospective placebo-controlled study, demonstrate an increased risk under combined estrogen/progestogen-, but not under estrogen-only therapy. However, up to now the clinical studies cannot discriminate between the various progestogens mostly due to too small patient numbers in the subgroups, and in most studies either medroxyprogesterone acetate or norethisterone have been used. However, there is evidence that the natural progesterone and dydrogesterone, possibly also the transdermal usage of synthetic progestogens, may have less risks, but this must be proven in further clinical trials. 相似文献
76.
Papadopoulos N Martin J Ruan Q Rafique A Rosconi MP Shi E Pyles EA Yancopoulos GD Stahl N Wiegand SJ 《Angiogenesis》2012,15(2):171-185
Pharmacological inhibition of VEGF-A has proven to be effective in inhibiting angiogenesis and vascular leak associated with
cancers and various eye diseases. However, little information is currently available on the binding kinetics and relative
biological activity of various VEGF inhibitors. Therefore, we have evaluated the binding kinetics of two anti-VEGF antibodies,
ranibizumab and bevacizumab, and VEGF Trap (also known as aflibercept), a novel type of soluble decoy receptor, with substantially
higher affinity than conventional soluble VEGF receptors. VEGF Trap bound to all isoforms of human VEGF-A tested with subpicomolar
affinity. Ranibizumab and bevacizumab also bound human VEGF-A, but with markedly lower affinity. The association rate for
VEGF Trap binding to VEGF-A was orders of magnitude faster than that measured for bevacizumab and ranibizumab. Similarly,
in cell-based bioassays, VEGF Trap inhibited the activation of VEGFR1 and VEGFR2, as well as VEGF-A induced calcium mobilization
and migration in human endothelial cells more potently than ranibizumab or bevacizumab. Only VEGF Trap bound human PlGF and
VEGF-B, and inhibited VEGFR1 activation and HUVEC migration induced by PlGF. These data differentiate VEGF Trap from ranibizumab
and bevacizumab in terms of its markedly higher affinity for VEGF-A, as well as its ability to bind VEGF-B and PlGF. 相似文献
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79.
Introduction
ADAMTS13 is a specific von Willebrand factor–cleaving protease. Severe deficiency of ADAMTS13 is the main cause of thrombotic thrombocytopenic purpura. ADAMTS13 is mainly synthesized and released from hepatic stellate cells and endothelial cells, but is also expressed in other cells, including kidney podocytes. Simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has a beneficial effect on atherosclerosis and also has anti-inflammatory and antithrombotic properties. A recent study indicates that ADAMTS13 reduces inflammatory plaque formation during early atherosclerosis in mice. In our study, we investigated the effects of simvastatin on inflammatory cytokines–induced ADAMTS13 expression in podocytes.Materials and Methods
A conditionally immortalized mouse podocyte cell line was utilized to study the expression of ADAMTS13 in podocytes. The influence of TNF-α, IL-4, IL-6 and simvastatin on ADAMTS13 was investigated. ADAMTS13 mRNA levels in podocytes were measured by using real-time PCR and protein levels were detected by Western blotting.Results
Simvastatin significantly up-regulated the expression levels of ADAMTS13 mRNA and protein in podocytes. IL-6 decreased ADAMTS13 expression, and TNF-α had no significant effects on ADAMTS13 expression in podocytes. IL-4 reduced ADAMTS13 mRNA expression but not its protein level. Simvastatin was able also reversed the inhibitory effect of IL-6.Conclusions
We demonstrate that simvastatin increases the expression of ADAMTS13 in a dose-dependent manner in podocytes, which likely contributes to the antithrombotic property of statin. Different inflammatory cytokines have different effects on the levels of ADAMTS13 mRNA expression and protein within podocytes. 相似文献80.
The sulfur/nitrogen co-doped activated carbon fiber (S/N-ACF) is prepared by the thermal treatment of thiourea-bonded hydroxyl-rich carbon fiber, which can bond the decomposition products of thiourea through hydrogen bond interaction to avoid the significant loss of sulfur and nitrogen sources during the thermal treatment process. The sulfur/nitrogen co-doped carbon fiber (S/N-CF) is prepared by the thermal treatment of thiourea-adsorbed carbon fiber. The doping degree of the carbon fiber is improved by reasonable strategy. S/N-ACF shows a higher amount of S/N doping (4.56 at% N and 3.16 at% S) than S/N-CF (1.25 at% N and 0.61 at% S). S/N-ACF with high S/N doping level involves highly active sites to improve the capacitive performance, and high delocalization electron to improve the conductivity and rate capability when compared with the normal S/N co-doped carbon fiber (S/N-CF). Accordingly, the specific capacitance increases from 1196 mF cm−2 for S/N-CF to 2704 mF cm−2 for S/N-ACF at 1 mA cm−2. The all-solid-state flexible S/N-ACF supercapacitor achieves 184.7 μW h cm−2 at 350 μW cm−2. The results suggest that S/N-ACF has potential application as a CF-based supercapacitor electrode material.Sulfur/nitrogen co-doped activated carbon fiber is prepared by thermal treatment of thiourea-bonded hydroxyl-rich carbon fiber, which achieves high doping level and electrochemical performance. 相似文献