110 research outputs found

    Tailoring seed oil composition in the real world: optimising omega-3 long chain polyunsaturated fatty acid accumulation in transgenic Camelina sativa

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    There is considerable interest in the de novo production of omega-3 long chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), not least of all given the importance of these fatty acids in both aquaculture and human nutrition. Previously we have demonstrated the feasibility of using metabolic engineering in transgenic plants (Camelina sativa) to modify the seed oil composition to now include EPA and/or DHA. In this study, we further tailored the seed oil profile to reduce the omega-6 content, and evaluated the performance of such GM plants under field conditions (i.e. environmental releases), in terms of agronomic performance and also the lipidomic profile of seed oil. We used MALDI- mass spectrometry imaging to identify discrete tissue-types in the seed in which these non-native fatty acids preferentially accumulated. Collectively, these data provide new insights into the complexity of plant lipid metabolism and the challenges associated with predictive manipulation of these pathways. However, this study identified the likely dispensable nature of a Δ12-desturase activity in our omega-3 metabolic engineering rationales for Camelina

    Reality Hackers: The Next Wave of Media Revolutionaries

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    Just as the printing press gave rise to the nation-state, emerging technologies are reshaping collective identities and challenging our understanding of what it means to be human. Should citizens have the right to be truly anonymous on-line? Should we be concerned about the fact that so many people are choosing to migrate to virtual worlds? Are injectible microscopic radio-frequency ID chips a blessing or a curse? Is the use of cognitive enhancing nootropics a human right or an unforgivable transgression? Should genomic data about human beings be hidden away with commercial patents or open-sourced like software? Should hobbyists known as biohackers be allowed to experiment with genetic engineering in their home laboratories? The time-frame for acting on such questions is relatively short, and these decisions are too important to be left up to a small handful of scientists and policymakers. If democracy is to continue as a viable alternative to technocracy, the average citizen must become more involved in these debates. To borrow a line from the computer visionary Ted Nelson, all of us can -- and must -- understand technology now. Challenging the popular stereotype of hackers as ciminal sociopaths, reality hackers uphold the basic tenets of what Steven Levy (1984) terms the hacker ethic. These core principles include a commitment to: sharing, openness, decentralization, public access to information, and the use of new technologies to make the world a better place.https://digitalcommons.trinity.edu/mono/1000/thumbnail.jp

    Simplicity in Visual Representation: A Semiotic Approach

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    Simplicity, as an ideal in the design of visual representations, has not received systematic attention. High-level guidelines are too general, and low-level guidelines too ad hoc, too numerous, and too often incompatible, to serve in a particular design situation. This paper reviews notions of visual simplicity in the literature within the analytical framework provided by Charles Morris' communication model, specifically, his trichotomy of communication levels—the syntactic, the semantic, and the pragmatic. Simplicity is ultimate ly shown to entail the adjudication of incompatibilities both within, and between, levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68281/2/10.1177_105065198700100103.pd

    Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people

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    The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30 to 80% depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures (word reading, nonword reading, spelling, phoneme awareness, and nonword repetition) in samples of 13,633 to 33,959 participants aged 5 to 26 y. We identified genome-wide significant association with word reading (rs11208009, P = 1.098 x 10(-8)) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP heritability, accounting for 13 to 26% of trait variability. Genomic structural equation modeling revealed a shared genetic factor explaining most of the variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence, and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis with neuroimaging traits identified an association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to the processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide avenues for deciphering the biological underpinnings of uniquely human traits.Peer reviewe

    Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities

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    Evolution of the avian β-defensin and cathelicidin genes

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    Background: β-defensins and cathelicidins are two families of cationic antimicrobial peptides (AMPs) with a broad range of antimicrobial activities that are key components of the innate immune system. Due to their important roles in host defense against rapidly evolving pathogens, the two gene families provide an ideal system for studying adaptive gene evolution. In this study we performed phylogenetic and selection analyses on β-defensins and cathelicidins from 53 avian species representing 32 orders to examine the evolutionary dynamics of these peptides in birds. Results and conclusions: Avian β-defensins are found in a gene cluster consisting of 13 subfamiles. Nine of these are conserved as one to one orthologs in all birds, while the others (AvBD1, AvBD3, AvBD7 and AvBD14) are more subject to gene duplication or pseudogenisation events in specific avian lineages. Avian cathelicidins are found in a gene cluster consisting of three subfamilies with species-specific duplications and gene loss. Evidence suggested that the propiece and mature peptide domains of avian cathelicidins are possibly co-evolving in such a way that the cationicity of the mature peptide is partially neutralised by the negative charge of the propiece prior to peptide secretion (further evidence obtained by repeating the analyses on primate cathelicidins). Negative selection (overall mean d

    Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people

    Get PDF
    The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30-80%, depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures: word reading, nonword reading, spelling, phoneme awareness, and nonword repetition, in samples of 13,633 to 33,959 participants aged 5-26 years. We identified genome-wide significant association with word reading (rs11208009, p=1.098 x 10-8) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP-heritability, accounting for 13-26% of trait variability. Genomic structural equation modelling revealed a shared genetic factor explaining most variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis of multivariate GWAS results with neuroimaging traits identified association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain, and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide new avenues for deciphering the biological underpinnings of uniquely human traits

    Functional Characterization of a Higher Plant Sphingolipid Δ4-Desaturase: Defining the Role of Sphingosine and Sphingosine-1-Phosphate in Arabidopsis

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    The role of Δ4-unsaturated sphingolipid long-chain bases such as sphingosine was investigated in Arabidopsis (Arabidopsis thaliana). Identification and functional characterization of the sole Arabidopsis ortholog of the sphingolipid Δ4-desaturase was achieved by heterologous expression in Pichia pastoris. A P. pastoris mutant disrupted in the endogenous sphingolipid Δ4-desaturase gene was unable to synthesize glucosylceramides. Synthesis of glucosylceramides was restored by the expression of Arabidopsis gene At4g04930, and these sphingolipids were shown to contain Δ4-unsaturated long-chain bases, confirming that this open reading frame encodes the sphingolipid Δ4-desaturase. At4g04930 has a very restricted expression pattern, transcripts only being detected in pollen and floral tissues. Arabidopsis insertion mutants disrupted in the sphingolipid Δ4-desaturase At4g04930 were isolated and found to be phenotypically normal. Sphingolipidomic profiling of a T-DNA insertion mutant indicated the absence of Δ4-unsaturated sphingolipids in floral tissue, also resulting in the reduced accumulation of glucosylceramides. No difference in the response to drought or water loss was observed between wild-type plants and insertion mutants disrupted in the sphingolipid Δ4-desaturase At4g04930, nor was any difference observed in stomatal closure after treatment with abscisic acid. No differences in pollen viability between wild-type plants and insertion mutants were detected. Based on these observations, it seems unlikely that Δ4-unsaturated sphingolipids and their metabolites such as sphingosine-1-phosphate play a significant role in Arabidopsis growth and development. However, Δ4-unsaturated ceramides may play a previously unrecognized role in the channeling of substrates for the synthesis of glucosylceramides

    Geometric Models of Deployable Metal Domes

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    This paper presents a new method for constructing metal domes. The method is basically one in which the whole structure is assembled initially at ground level in an essentially flat condition. By the use of posttensioning in an appropriate way, the space structure can be erected by deflecting into its final shape and into position. From the principle of deployable structures, this paper concludes that the basic problem of such a method is the geometric compatibility condition between the initial and final configurations. The geometric models that reflect the relationship between the planar layout and the space shape is established to describe the geometric compatibility condition of domes. An example of such deployable metal domes, taking into account the geometric models, mechanism condition, and appropriate posttensioning method, is given to illustrate the method. The finite-element analysis results of the example show that the proposed shape-formation method is feasible and the established geometric models are reliable. Potentially, this procedure can offer economics over traditional methods of construction of metal domes
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