760 research outputs found

    Production of amylopectin and high-amylose starch in separate potato genotypes

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    Starch is one of the most important processed products from agriculture. Two main outlets can be identified; starch is either enzymatically processed for the production of sweeteners and as raw material for fermentation or channelled to various applications as dry starch. Native or chemically modified starches are utilized in food as well as non-food applications, where the specific physicochemical properties are main determinants for their respective use. Starch consists of two different molecules, amylose and amylopectin. To be able to take the full benefit of the unique properties of either component it is of interest to divide the production of amylose and amylopectin into separate plant genotypes. In the presented work, potatoes producing either amylopectin or high-amylose starch were achieved using genetic modification. For potato transformation a highly efficient protocol was developed for a herbicide selection gene instead of the commonly used nptII antibiotic selection gene. In order to achieve respective starch qualities, the expression of genes important for amylopectin or amylose synthesis was silenced. Antisense technology as well as the expression of dsRNA was investigated where the expression of dsRNA was determined to be at least ten-fold more efficient for gene silencing. An added benefit of dsRNA expression was that a higher fraction of silenced transgenic lines compared to the use antisense were associated with single copy T-DNA integrations. One amylopectin potato line was furthermore characterized regarding genetic and chemical composition. The T-DNA was found integrated as an inverted repeat with the inverted repeat region extending into potato chromosomal DNA. This transgenic locus was found to be more consistent with integration into a double-stranded chromosomal break than insertion by a mechanism nicking one strand of the locus. The high-amylose trait generally resulted in a higher tuber fresh weight yield, much elevated sugar levels and a decreased starch content. Amylose levels were obtained where very limited amounts of material recognizable as amylopectin could be found. The production of amylopectin and amylose was divided into separate genotypes but additional factors are needed to be able to produce amylose at levels comparable to starch contents of cultivated potatoes

    Starch biosynthetic genes and enzymes are expressed and active in the absence of starch accumulation in sugar beet tap-root

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    BACKGROUND: Starch is the predominant storage compound in underground plant tissues like roots and tubers. An exception is sugar beet tap-root (Beta vulgaris ssp altissima) which exclusively stores sucrose. The underlying mechanism behind this divergent storage accumulation in sugar beet is currently not fully known. From the general presence of starch in roots and tubers it could be speculated that the lack in sugar beet tap-roots would originate from deficiency in pathways leading to starch. Therefore with emphasis on starch accumulation, we studied tap-roots of sugar beet using parsnip (Pastinaca sativa) as a comparator. RESULTS: Metabolic and structural analyses of sugar beet tap-root confirmed sucrose as the exclusive storage component. No starch granules could be detected in tap-roots of sugar beet or the wild ancestor sea beet (Beta vulgaris ssp. maritima). Analyses of parsnip showed that the main storage component was starch but tap-root tissue was also found to contain significant levels of sugars. Surprisingly, activities of four main starch biosynthetic enzymes, phosphoglucomutase, ADP-glucose pyrophosphorylase, starch synthase and starch branching enzyme, were similar in sugar beet and parsnip tap-roots. Transcriptional analysis confirmed expression of corresponding genes. Additionally, expression of genes involved in starch accumulation such as for plastidial hexose transportation and starch tuning functions could be determined in tap-roots of both plant species. Conclusion: Considering underground storage organs, sugar beet tap-root upholds a unique property in exclusively storing sucrose. Lack of starch also in the ancestor sea beet indicates an evolved trait of biological importance. Our findings in this study show that gene expression and enzymatic activity of main starch biosynthetic functions are present in sugar beet tap-root during storage accumulation. In view of this, the complete lack of starch in sugar beet tap-roots is enigmatic

    AD/HD and autism spectrum disorders in adults

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    Background: Attention deficit/hyperactivity disorder (AD/HD) and autism spectrum disorders (ASDs) are early-onset, but often life-time impairing, neurodevelopmental disorders. They are highly overlapping and seem to carry considerable risks of negative outcomes, psychiatrically and psychosocially. Childhood hyperactivity is a known risk factor for early-onset conduct disorder (CD), but details concerning the associations between neurodevelopmental problems, aggression, and antisocial personality disorder (ASPD) in adult age are still uncertain. The current diagnostic subdivision of the ASDs is based on children, while the adult characteristics, including patterns of comorbidity and psychosocial adversities, have been less studied, especially in subjects without concomitant intellectual disability. Objectives: The overall aim of this thesis was to describe the adult outcome of AD/HD and ASDs. Specific aims were to: (1) review prospective, longitudinal studies of the adult outcome of childhood hyperactivity, equivalent to AD/HD, with special regard to ASPD, (2) investigate the relationships between AD/HD, ASDs, and different types of aggressive behaviours, (3) describe the clinical presentation, including personality development and psychosocial outcome, in normal-intelligence adult subjects with ASDs. Method: The first paper is a systematic meta-analysis of published studies. The subsequent studies are descriptive analyses of common clinical assessment protocols from consecutive groups of adults either referred for clinical evaluations of childhood-onset neuropsychiatric disorders, for forensic psychiatric investigations, or recruited to a population-based, longitudinal study of teenage-onset anorexia nervosa (AN). Results: Childhood hyperactivity increases the risk for CD, which is found in at least one-third of all hyperactive children, forming the starting point for the development of aggressive antisociality in adulthood in about half of cases with the combination of hyperactivity and CD in childhood. Support for the hypothesis that childhood hyperactivity, in the absence of early CD, carries a risk for adult ASPD, is still lacking (Paper I). Both conditions are, however, predictors of aggression in adults, together with substance-related disorders and poor development of the character trait Cooperativeness. ASD traits or symptoms did not generally predict aggression but may be associated with unique violent offences (Paper II). Among subjects with normal-intelligence ASDs, life-time psychiatric comorbidity was very high, and measures of outcome indicated low psychosocial functioning. AD/HD was common in all ASD subject categories studied with the notable exception of subjects with AN, none of whom had AD/HD. ASPD and substance-related disorders were more common in patients with an atypical ASD as compared to Asperger´s disorder or autistic disorder. Among all adults diagnosed with an ASD, less than half led an independent life and comparatively few had ever had a long-term relationship. Female subjects more often reported having been bullied at school than male subjects (Paper III and IV). Discussion and conclusions: Childhood-onset neuropsychiatric conditions such as AD/HD and ASDs are relevant for adult psychiatric phenotypes but insufficiently studied. Current classifications suffer from the hiatus between child- and adolescent psychiatry and adult psychiatry and future diagnostic concepts ought to be longitudinal with a life-time perspective on cognitive and emotional development and a patient-centred focus rather than fragmented into complex patterns of “comorbidities”

    A dialogic approach for the artist as an interface in an intercultural society

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    Can we learn to listen? Or to allow silence to speak to us? Can we visualize the space among us and inhabit it with our memories? These are among the questions raised by, and embedded in, my recent participatory art project “lo scarto,” which evolved through the relational dynamics within the group. It was informed by the Reciprocal Maieutics Approach (RMA; Dolci, 1973), a pedagogic process based on collective exploration of individuals’ experience and intuition. This enabled inter-subjective exchange, the activation of history and memories, and the construction of a narrative related to the current intercultural process taking place in Italy. My creative process is here discussed as research as art practice, in relation to socially engaged and dialogic art and communicative memory, to act as an interface in an intercultural society

    Ten steps or climbing a mountain: A study of Australian health professionals' perceptions of implementing the baby friendly health initiative to protect, promote and support breastfeeding

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    Background: The Baby Friendly Hospital (Health) Initiative (BFHI) is a global initiative aimed at protecting, promoting and supporting breastfeeding and is based on the ten steps to successful breastfeeding. Worldwide, over 20,000 health facilities have attained BFHI accreditation but only 77 Australian hospitals (approximately 23%) have received accreditation. Few studies have investigated the factors that facilitate or hinder implementation of BFHI but it is acknowledged this is a major undertaking requiring strategic planning and change management throughout an institution. This paper examines the perceptions of BFHI held by midwives and nurses working in one Area Health Service in NSW, Australia. Methods: The study used an interpretive, qualitative approach. A total of 132 health professionals, working across four maternity units, two neonatal intensive care units and related community services, participated in 10 focus groups. Data were analysed using thematic analysis. Results: Three main themes were identified: ‘Belief and Commitment’; ‘Interpreting BFHI’ and ‘Climbing a Mountain’. Participants considered the BFHI implementation a high priority; an essential set of practices that would have positive benefits for babies and mothers both locally and globally as well as for health professionals. It was considered achievable but would take commitment and hard work to overcome the numerous challenges including a number of organisational constraints. There were, however, differing interpretations of what was required to attain BFHI accreditation with the potential that misinterpretation could hinder implementation. A model described by Greenhalgh and colleagues on adoption of innovation is drawn on to interpret the findings. Conclusion: Despite strong support for BFHI, the principles of this global strategy are interpreted differently by health professionals and further education and accurate information is required. It may be that the current processes used to disseminate and implement BFHI need to be reviewed. The findings suggest that there is a contradiction between the broad philosophical stance and best practice approach of this global strategy and the tendency for health professionals to focus on the ten steps as a set of tasks or a checklist to be accomplished. The perceived procedural approach to implementation may be contributing to lower rates of breastfeeding continuation

    Potato trait development going fast-forward with genome editing

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    Implementations and improvements of genome editing techniques used in plant science have increased exponentially. For some crops, such as potato, the use of transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR) has moved to the next step of trait development and field trials, and should soon be applied to commercial cultivation

    Potato trait development going fast-forward with genome editing

    Get PDF
    Implementations and improvements of genome editing techniques used in plant science have increased exponentially. For some crops, such as potato, the use of transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR) has moved to the next step of trait development and field trials, and should soon be applied to commercial cultivation

    GBSS mutations in an SBE mutated background restore the potato starch granule morphology and produce ordered granules despite differences to native molecular structure

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    Potato starch with mutations in starch branching enzyme genes (SBEI, SBEII) and granule-bound starch synthase gene (GBSS) was characterized for molecular and thermal properties. Mutations in GBSS were here stacked to a previously developed SBEI and SBEII mutation line. Additionally, mutations in the GBSS gene alone were induced in the wild-type variety for comparison. The parental line with mutations in the SBE genes showed a - 40 % increase in amylose content compared with the wild-type. Mutations in GBSS-SBEI-SBEII produced non-waxy, low-amylose lines compared with the wild-type. An exception was a line with one remaining GBSS wild-type allele, which displayed -80 % higher amylose content than wild-type. Stacked mutations in GBSS in the SBEI-SBEII parental line caused alterations in amylopectin chain length distribution and building block size categories of whole starch. Correlations between size categories of building blocks and unit chains of amylopectin were observed. Starch in GBSS-SBEI-SBEII mutational lines had elevated peak temperature of gelatinization, which was positively correlated with large building blocks
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