19 research outputs found

    Tissue tolerance: an essential but elusive trait for salt-tolerant crops

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    For a plant to persist in saline soil, osmotic adjustment of all plant cells is essential. The more salt-tolerant species accumulate Na+ and Cl– to concentrations in leaves and roots that are similar to the external solution, thus allowing energy-efficient osmotic adjustment. Adverse effects of Na+ and Cl– on metabolism must be avoided, resulting in a situation known as ‘tissue tolerance’. The strategy of sequestering Na+ and Cl– in vacuoles and keeping concentrations low in the cytoplasm is an important contributor to tissue tolerance. Although there are clear differences between species in the ability to accommodate these ions in their leaves, it remains unknown whether there is genetic variation in this ability within a species. This viewpoint considers the concept of tissue tolerance, and how to measure it. Four conclusions are drawn: (1) osmotic adjustment is inseparable from the trait of tissue tolerance; (2) energy-efficient osmotic adjustment should involve ions and only minimal organic solutes; (3) screening methods should focus on measuring tolerance, not injury; and (4) high-throughput protocols that avoid the need for control plants and multiple Na+ or Cl- measurements should be developed. We present guidelines to identify useful genetic variation in tissue tolerance that can be harnessed for plant breeding of salt tolerance

    Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

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    OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

    Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels

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    Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P <10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P <5 x 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.Peer reviewe

    Language, Landscape and the Sublime

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    We are almost overwhelmed with data showing a world under threat and becoming increasingly threatening (a contemporary re-telling of Burke’s Sublime?). But science and its knowledges are failing to move us, to jolt us into feeling the true fragility of the planet in which we all live, despite the apparent clarity of the evidence and the increasing baldness of its language. Science and hysteria are not comfortable bedfellows, but seem increasingly within sniffing distance of one another. This two-day symposium draws together artists and thinkers from a wide range of disciplines to explore ways in which landscape –– and the ways we represent it –– connects deeply to our lives and underpins our relationship to the world. The contemporary array of narratives of landscape expose how we feel about (and how we become estranged from) this astounding place we all share. As we contemplate the fragility of our planet fearful narratives confound our complex and worried entanglements with the world around us. The dark complexity of the post-enlightenment concept of the Sublime (in which ‘the dominant feature is the presence or idea of transcendental immensity or greatness [and which]…inspires awe and reverence, or possibly fear’ (Bell, Lyall 2002)), and the comparative gaiety of the Picturesque were spurs to reshape (literally and metaphorically) the ways in which we saw and lived in the world. Of late dismissed and subsumed by the technocratic tendencies of modernism, Romantic notions of landscape and nature have felt somewhat risible: perhaps it is time to re-kindle the romantic as we begin to understand the need to grieve for what we have already lost and reclaim beauty for an alienated modern world? The philosophical romanticism of Burke, Poussin and others, and the expression of the sublime through poetry and painting that followed it profoundly shaped our thinking and feeling about landscape and about the natural world. The Americans (Thoreau, Emerson) embraced wilderness, not surprisingly perhaps given the vastness and emptiness of their world; here in Europe the focus seems smaller, tamed, shaped, idealised, if no less numinous. What we perceive as natural ideal landscapes have typically been shaped through deliberate aesthetic design intervention and/or the exigencies of farming and agriculture. It was the ‘epiphanic’ sense of landscape (Wylie) – the revealing of beauty from coming upon it – that gave birth to a newly-romanticised and idealised view of what had until that time been largely ignored as the ‘thing around us’. But the heady days of the Romantics, the Picturesque and the Sublime in both visual and written language created another moment in time from which we have looked at the world around us in a different way. So what of today? Is our relationship with the natural world and our ability to understand the threats weighing upon it now being transformed: through a still emergent (new romantic perhaps) writing, through other forms of representation such as Hockney’s rich exploration of his birthland? Notions of the Sublime helped the Romantics elicit an entirely new set of emotions, rekindling an a religious numinism, awe and sense of mystery and the unknowable in our connection to the natural world. Perhaps we cannot live without this in our lives. Despite decades of rejection, dismissal and even small shudders of revulsion, is it time to re-embrace our love for and fear of the Sublime and in so doing find deeper and more engaged pathways, byways and languages to love the world around us

    Schizochytrium sp. (T18) Oil as a Fish Oil Replacement in Diets for Juvenile Rainbow Trout (Oncorhynchus mykiss): Effects on Growth Performance, Tissue Fatty Acid Content, and Lipid-Related Transcript Expression

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    In this study, we evaluated whether oil extracted from the marine microbe, Schizochytrium sp. (strain T18), with high levels of docosahexaenoic acid (DHA), could replace fish oil (FO) in diets for rainbow trout (Oncorhynchus mykiss). Three experimental diets were tested: (1) a control diet with fish oil (FO diet), (2) a microbial oil (MO) diet with a blend of camelina oil (CO) referred to as MO/CO diet, and (3) a MO diet (at a higher inclusion level). Rainbow trout (18.8 ± 2.9 g fish−1 initial weight ± SD) were fed for 8 weeks and evaluated for growth performance, fatty acid content and transcript expression of lipid-related genes in liver and muscle. There were no differences in growth performance measurements among treatments. In liver and muscle, eicosapentaenoic acid (EPA) was highest in trout fed the FO diet compared to the MO/CO and MO diets. Liver DHA was highest in trout fed the MO/CO diet compared to the FO and MO diets. Muscle DHA was highest in trout fed the MO and MO/CO diets compared to the FO diet. In trout fed the MO/CO diet, compared to the MO diet, fadsd6b was higher in both liver and muscle. In trout fed the FO or MO/CO diets, compared to the MO diet, cox1a was higher in both liver and muscle, cpt1b1a was higher in liver and cpt1a1a, cpt1a1b and cpt1a2a were higher in muscle. Schizochytrium sp. (T18) oil was an effective source of DHA for rainbow trout

    Schizochytrium sp. (T18) Oil as a Fish Oil Replacement in Diets for Juvenile Rainbow Trout (Oncorhynchus mykiss): Effects on Growth Performance, Tissue Fatty Acid Content, and Lipid-Related Transcript Expression

    No full text
    In this study, we evaluated whether oil extracted from the marine microbe, Schizochytrium sp. (strain T18), with high levels of docosahexaenoic acid (DHA), could replace fish oil (FO) in diets for rainbow trout (Oncorhynchus mykiss). Three experimental diets were tested: (1) a control diet with fish oil (FO diet), (2) a microbial oil (MO) diet with a blend of camelina oil (CO) referred to as MO/CO diet, and (3) a MO diet (at a higher inclusion level). Rainbow trout (18.8 ± 2.9 g fish−1 initial weight ± SD) were fed for 8 weeks and evaluated for growth performance, fatty acid content and transcript expression of lipid-related genes in liver and muscle. There were no differences in growth performance measurements among treatments. In liver and muscle, eicosapentaenoic acid (EPA) was highest in trout fed the FO diet compared to the MO/CO and MO diets. Liver DHA was highest in trout fed the MO/CO diet compared to the FO and MO diets. Muscle DHA was highest in trout fed the MO and MO/CO diets compared to the FO diet. In trout fed the MO/CO diet, compared to the MO diet, fadsd6b was higher in both liver and muscle. In trout fed the FO or MO/CO diets, compared to the MO diet, cox1a was higher in both liver and muscle, cpt1b1a was higher in liver and cpt1a1a, cpt1a1b and cpt1a2a were higher in muscle. Schizochytrium sp. (T18) oil was an effective source of DHA for rainbow trout

    Beyond urban legends : an emerging framework of urban ecology, as illustrated by the Baltimore Ecosystem Study

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    The emerging discipline of urban ecology is shifting focus from ecological processes embedded within cities to integrative studies of large urban areas as biophysical-social complexes. Yet this discipline lacks a theory. Results from the Baltimore Ecosystem Study, part of the Long Term Ecological Research Network, expose new assumptions and test existing assumptions about urban ecosystems. The findings suggest a broader range of structural and functional relationships than is often assumed for urban ecological systems. We address the relationships between social status and awareness of environmental problems, and between race and environmental hazard. We present patterns of species diversity, riparian function, and stream nitrate loading. In addition, we probe the suitability of land-use models, the diversity of soils, and the potential for urban carbon sequestration. Finally, we illustrate lags between social patterns and vegetation, the biogeochemistry of lawns, ecosystem nutrient retention, and social-biophysical feedbacks. These results suggest a framework for a theory of urban ecosystems

    A Search for Low-mass Dark Matter via Bremsstrahlung Radiation and the Migdal Effect in SuperCDMS

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    In this paper, we present a re-analysis of SuperCDMS data using a profile likelihood approach to search for sub-GeV dark matter particles (DM) through two inelastic scattering channels: bremsstrahlung radiation and the Migdal effect. By considering possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that would otherwise be undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to 220 MeV/c2220~\textrm{MeV}/c^2 at 2.7×1030 cm22.7 \times 10^{-30}~\textrm{cm}^2 via the bremsstrahlung channel. The Migdal channel search excludes DM masses down to 30 MeV/c230~\textrm{MeV}/c^2 at 5.0×1030 cm25.0 \times 10^{-30}~\textrm{cm}^2.Comment: This paper is being withdrawn due to an error in data selection during the analysis. Although incorrect, the limits are roughly representative of the sensitivity. The new corrected version of the result will be uploaded once read
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