740 research outputs found

    The evolution of biofilm-forming Wrinkly Spreaders in static microcosms and drip-fed columns selects for subtle differences in wrinkleality and fitness

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    Experimental evolution studies are used to investigate bacterial adaptive radiation in simple microcosms. In the case of the Wrinkly Spreader, a class of biofilm-forming adaptive mutants of Pseudomonas fluorescens SBW25, the current paradigm is that they are only evolutionarily successful in static microcosms where they outcompete other lineages for O2 at the air–liquid interface. However, we have isolated Wrinkly Spreaders from drip-fed glass bead columns as an example of parallel evolution. These mutants are adaptive, with competitive fitness advantages on columns of 1.28–1.78. This might be explained by the enhanced attachment characteristically shown by Wrinkly Spreaders, allowing them to resist liquid flow through the column pore network. A comparison of column and static microcosm-isolated Wrinkly Spreaders showed that many aspects of wrinkleality, including colony reversion, microcosm growth, biofilm strength and attachment, as well as fitness in static microcosms, were significantly different within and between the two groups of mutants. These findings indicate that the two environments had selected for Wrinkly Spreaders with subtly differing degrees of wrinkleality and fitnesses, suggesting that aspects of the Wrinkly Spreader phenotype may have different relative values in static microcosms and drip-fed columns

    Development and mapping of SNP assays in allotetraploid cotton

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    A narrow germplasm base and a complex allotetraploid genome have made the discovery of single nucleotide polymorphism (SNP) markers difficult in cotton (Gossypiumhirsutum). To generate sequence for SNP discovery, we conducted a genome reduction experiment (EcoRI, BafI double digest, followed by adapter ligation, biotin–streptavidin purification, and agarose gel separation) on two accessions of G. hirsutum and two accessions of G. barbadense. From the genome reduction experiment, a total of 2.04 million genomic sequence reads were assembled into contigs with an N50 of 508 bp and analyzed for SNPs. A previously generated assembly of expressed sequence tags (ESTs) provided an additional source for SNP discovery. Using highly conservative parameters (minimum coverage of 8× at each SNP and 20% minor allele frequency), a total of 11,834 and 1,679 non-genic SNPs were identified between accessions of G. hirsutum and G. barbadense in genome reduction assemblies, respectively. An additional 4,327 genic SNPs were also identified between accessions of G. hirsutum in the EST assembly. KBioscience KASPar assays were designed for a portion of the intra-specific G. hirsutum SNPs. From 704 non-genic and 348 genic markers developed, a total of 367 (267 non-genic, 100 genic) mapped in a segregating F2 population (Acala Maxxa × TX2094) using the Fluidigm EP1 system. A G. hirsutum genetic linkage map of 1,688 cM was constructed based entirely on these new SNP markers. Of the genic-based SNPs, we were able to identify within which genome (‘A’ or ‘D’) each SNP resided using diploid species sequence data. Genetic maps generated by these newly identified markers are being used to locate quantitative, economically important regions within the cotton genome

    Locating and building knowledges outside of the academy : approaches to engaged teaching at the University of Sheffield

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    This article draws on three case studies, which illuminate a number of practical, ethical and intellectual issues that arise from engaged teaching activities within the curriculum. Projects from the disciplines of Architecture, English and Journalism Studies illustrate the possibilities offered by learning and teaching projects which emphasise public facing, co-produced knowledge as central components. It is argued that such approaches enable dynamic forms of learning to emerge, which work to expand the parameters of subject-specific knowledge while enabling the development of citizenship attributes and employability skills amongst students in ways that deepen, rather than dilute, intellectual rigour. The article locates these practical pedagogical reflections within theoretical frameworks offered by those working (largely in North America* on publicly engaged approaches to scholarship and seeks to draw connections with contemporary developments in learning and teaching in the UK. Keywords: civic university; engaged teaching; engaged scholarship; co-productio

    Development and characterization of InDel markers for Lupinus luteus L. (Fabaceae) and cross-species amplification in other Lupin species

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    Background: Strong artificial selection and/or natural bottle necks may limit genetic variation in domesticated species. Lupinus luteus, an orphan temperate crop, has suffered diversity reductions during its bitter/sweet alkaloid domestication history, limiting breeding efforts and making molecular marker development a difficult task. The main goal of this research was to generate new polymorphic insertion\u2013deletion (InDel) markers to aid yellow lupin genetics and breeding. By combining genomic reduction libraries and next generation sequencing, several polymorphic InDel markers were developed for L. luteus L. Results: A total of 118 InDel in silico polymorphic markers were identified. Eighteen InDel primer sets were evaluated in a diverse L. luteus core collection, where amplified between 2\u20133 alleles per locus. Observed heterozygosity (HO; 0.0648 to 0.5564) and polymorphic information content (PIC; 0.06 to 0.48) estimations revealed a moderate level of genetic variation across L. luteus accessions. In addition, ten and nine InDel loci amplified successfully Lupinus hispanicus Boiss & Reut, and Lupinus mutabilis Sweet, respectively, two L. luteus close relatives. PCA analysis identified two L. luteus clusters, most likely explained by the domestication species history. Conclusion: The development of InDel markers will facilitate the study of genetic diversity across L. luteus populations, as well as among closely related species

    The Gossypium longicalyx genome as a resource for cotton breeding and evolution

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    Cotton is an important crop that has made significant gains in production over the last century. Emerging pests such as the reniform nematode have threatened cotton production. The rare African diploid specie

    Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium

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    Background The majority of commercial cotton varieties planted worldwide are derived from Gossypium hirsutum, which is a naturally occurring allotetraploid produced by interspecific hybridization of A- and D-genome diploid progenitor species. While most cotton species are adapted to warm, semi-arid tropical and subtropical regions, and thus perform well in these geographical areas, cotton seedlings are sensitive to cold temperature, which can significantly reduce crop yields. One of the common biochemical responses of plants to cold temperatures is an increase in omega-3 fatty acids, which protects cellular function by maintaining membrane integrity. The purpose of our study was to identify and characterize the omega-3 fatty acid desaturase (FAD) gene family in G. hirsutum, with an emphasis on identifying omega-3 FADs involved in cold temperature adaptation. Results Eleven omega-3 FAD genes were identified in G. hirsutum, and characterization of the gene family in extant A and D diploid species (G. herbaceum and G. raimondii, respectively) allowed for unambiguous genome assignment of all homoeologs in tetraploid G. hirsutum. The omega-3 FAD family of cotton includes five distinct genes, two of which encode endoplasmic reticulum-type enzymes (FAD3-1 and FAD3-2) and three that encode chloroplast-type enzymes (FAD7/8-1, FAD7/8-2, and FAD7/8-3). The FAD3-2 gene was duplicated in the A genome progenitor species after the evolutionary split from the D progenitor, but before the interspecific hybridization event that gave rise to modern tetraploid cotton. RNA-seq analysis revealed conserved, gene-specific expression patterns in various organs and cell types and semi-quantitative RT-PCR further revealed that FAD7/8-1 was specifically induced during cold temperature treatment of G. hirsutum seedlings. Conclusions The omega-3 FAD gene family in cotton was characterized at the genome-wide level in three species, showing relatively ancient establishment of the gene family prior to the split of A and D diploid progenitor species. The FAD genes are differentially expressed in various organs and cell types, including fiber, and expression of the FAD7/8-1 gene was induced by cold temperature. Collectively, these data define the genetic and functional genomic properties of this important gene family in cotton and provide a foundation for future efforts to improve cotton abiotic stress tolerance through molecular breeding approaches

    Christian Higher Education in Europe: A Historical Overview

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    The history of Christian higher education in Europe may be analyzed in terms of seven eras. From their medieval origins in scholasticism and the practical needs of students and rulers, universities passed through Renaissance humanism to a period of decay, yet remained substantially Christian in intent. The Enlightenment exercised a partially secularizing influence, and the neohumanist reaction against it also tended to dilute the faith. The recent era of the late 20th and early 21st centuries has been associated with the rise of postmodernism and the involvement of the state in the quest for relevance. A Christian response to contemporary circumstances is to engage with the cultural currents of the present day and, in drawing on the thought of John Henry Newman and Sir Walter Moberly, to ensure the integration of Christianity into higher education so that discussion of ultimate questions is informed by the Christian faith
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