469 research outputs found

    Volatile profiling reveals intracellular metabolic changes in Aspergillus parasticus: veA regulates branched chain amino acid and ethanol metabolism

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    Background: Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by Aspergillus parasiticus in an attempt to define the association of secondary metabolism with other metabolic and cellular processes. Results: Volatile compounds were examined using solid phase microextraction - gas chromatography/mass spectrometry. In the wild type strain Aspergillus parasiticus SU-1, the largest group of volatiles included compounds derived from catabolism of branched chain amino acids (leucine, isoleucine, and valine); we also identified alcohols, esters, aldehydes, and lipid-derived volatiles. The number and quantity of the volatiles produced depended on media composition, time of incubation, and light-dark status. A block in aflatoxin biosynthesis or disruption of the global regulator veA affected the volatile profile. In addition to its multiple functions in secondary metabolism and development, VeA negatively regulated catabolism of branched chain amino acids and synthesis of ethanol at the transcriptional level thus playing a role in controlling carbon flow within the cell. Finally, we demonstrated that volatiles generated by a veA disruption mutant are part of the complex regulatory machinery that mediates the effects of VeA on asexual conidiation and sclerotia formation. Conclusions: 1) Volatile profiling provides a rapid, effective, and powerful approach to identify changes in intracellular metabolic networks in filamentous fungi. 2) VeA coordinates the biosynthesis of secondary metabolites with catabolism of branched chain amino acids, alcohol biosynthesis, and b-oxidation of fatty acids. 3) Intracellular chemical development in A. parasiticus is linked to morphological development. 4) Understanding carbon flow through secondary metabolic pathways and catabolism of branched chain amino acids is essential for controlling and customizing production of natural products

    Volatile profiling reveals intracellular metabolic changes in Aspergillus parasiticus: veA regulates branched chain amino acid and ethanol metabolism

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    <p>Abstract</p> <p>Background</p> <p>Filamentous fungi in the genus <it>Aspergillus </it>produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by <it>Aspergillus parasiticus </it>in an attempt to define the association of secondary metabolism with other metabolic and cellular processes.</p> <p>Results</p> <p>Volatile compounds were examined using solid phase microextraction - gas chromatography/mass spectrometry. In the wild type strain <it>Aspergillus parasiticus </it>SU-1, the largest group of volatiles included compounds derived from catabolism of branched chain amino acids (leucine, isoleucine, and valine); we also identified alcohols, esters, aldehydes, and lipid-derived volatiles. The number and quantity of the volatiles produced depended on media composition, time of incubation, and light-dark status. A block in aflatoxin biosynthesis or disruption of the global regulator <it>veA </it>affected the volatile profile. In addition to its multiple functions in secondary metabolism and development, VeA negatively regulated catabolism of branched chain amino acids and synthesis of ethanol at the transcriptional level thus playing a role in controlling carbon flow within the cell. Finally, we demonstrated that volatiles generated by a <it>veA </it>disruption mutant are part of the complex regulatory machinery that mediates the effects of VeA on asexual conidiation and sclerotia formation.</p> <p>Conclusions</p> <p>1) Volatile profiling provides a rapid, effective, and powerful approach to identify changes in intracellular metabolic networks in filamentous fungi. 2) VeA coordinates the biosynthesis of secondary metabolites with catabolism of branched chain amino acids, alcohol biosynthesis, and ÎČ-oxidation of fatty acids. 3) Intracellular chemical development in <it>A. parasiticus </it>is linked to morphological development. 4) Understanding carbon flow through secondary metabolic pathways and catabolism of branched chain amino acids is essential for controlling and customizing production of natural products.</p

    Complete lung agenesis caused by complex genomic rearrangements with neo-TAD formation at the SHH locus

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    During human organogenesis, lung development is a timely and tightly regulated developmental process under the control of a large number of signaling molecules. Understanding how genetic variants can disturb normal lung development causing different lung malformations is a major goal for dissecting molecular mechanisms during embryogenesis. Here, through exome sequencing (ES), array CGH, genome sequencing (GS) and Hi-C, we aimed at elucidating the molecular basis of bilateral isolated lung agenesis in three fetuses born to a non-consanguineous family. We detected a complex genomic rearrangement containing duplicated, triplicated and deleted fragments involving the SHH locus in fetuses presenting complete agenesis of both lungs and near-complete agenesis of the trachea, diagnosed by ultrasound screening and confirmed at autopsy following termination. The rearrangement did not include SHH itself, but several regulatory elements for lung development, such as MACS1, a major SHH lung enhancer, and the neighboring genes MNX1 and NOM1. The rearrangement incorporated parts of two topologically associating domains (TADs) including their boundaries. Hi-C of cells from one of the affected fetuses showed the formation of two novel TADs each containing SHH enhancers and the MNX1 and NOM1 genes. Hi-C together with GS indicate that the new 3D conformation is likely causative for this condition by an inappropriate activation of MNX1 included in the neo-TADs by MACS1 enhancer, further highlighting the importance of the 3D chromatin conformation in human disease

    Assessing the efficacy, safety and utility of closed-loop insulin delivery compared with sensor-augmented pump therapy in very young children with type 1 diabetes (KidsAP02 study): an open-label, multicentre, multinational, randomised cross-over study protocol

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    Introduction: Diabetes management in very young children remains challenging. Glycaemic targets are achieved at the expense of high parental diabetes management burden and frequent hypoglycaemia, impacting quality of life for the whole family. Our objective is to assess whether automated insulin delivery can improve glycaemic control and alleviate the burden of diabetes management in this particular age group. Methods and analysis: The study adopts an open-label, multinational, multicentre, randomised, crossover design and aims to randomise 72 children aged 1-7 years with type 1 diabetes on insulin pump therapy. Following screening, participants will receive training on study insulin pump and study continuous glucose monitoring devices. Participants will be randomised to 16-week use of the hybrid closed-loop system (intervention period) or to 16-week use of sensor-augmented pump therapy (control period) with 1-4 weeks washout period before crossing over to the other arm. The order of the two study periods will be random. The primary endpoint is the between-group difference in time spent in the target glucose range from 3.9 to 10.0 mmol/L based on sensor glucose readings during the 16-week study periods. Analyses will be conducted on an intention-to-treat basis. Key secondary endpoints are between group differences in time spent above and below target glucose range, glycated haemoglobin and average sensor glucose. Participants' and caregivers' experiences will be evaluated using questionnaires and qualitative interviews, and sleep quality will be assessed. A health economic analysis will be performed. Ethics and dissemination: Ethics approval has been obtained from Cambridge East Research Ethics Committee (UK), Ethics Committees of the University of Innsbruck, the University of Vienna and the University of Graz (Austria), Ethics Committee of the Medical Faculty of the University of Leipzig (Germany) and Comité National d'Ethique de Recherche (Luxembourg). The results will be disseminated by peer-reviewed publications and conference presentations

    A Screening Tool to Quickly Identify Movement Disorders in Patients with Inborn Errors of Metabolism

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    Background: Movement disorders are frequent in patients with inborn errors of metabolism (IEMs) but poorly recognized, particularly by nonmovement disorder specialists. We propose an easy‐to‐use clinical screening tool to help recognize movement disorders. Objective: The aim is to develop a user‐friendly rapid screening tool for nonmovement disorder specialists to detect moderate and severe movement disorders in patients aged ≄4 years with IEMs. Methods: Videos of 55 patients with different IEMs were scored by experienced movement disorder specialists (n = 12). Inter‐rater agreements were determined on the presence and subtype of the movement disorder. Based on ranking and consensus, items were chosen to be incorporated into the screening tool. Results: A movement disorder was rated as present in 80% of the patients, with a moderate inter‐rater agreement (Îș =0.420, P < 0.001) on the presence of a movement disorder. When considering only moderate and severe movement disorders, the inter‐rater agreement increased to almost perfect (Îș = 0.900, P < 0.001). Dystonia was most frequently scored (27.3%) as the dominant phenotype. Treatment was mainly suggested for patients with moderate or severe movement disorders. Walking, observations of the arms, and drawing a spiral were found to be the most informative tasks and were included in the screening tool. Conclusions: We designed a screening tool to recognize movement disorders in patients with IEMs. We propose that this screening tool can contribute to select patients who should be referred to a movement disorder specialist for further evaluation and, if necessary, treatment of the movement disorder. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

    Modalités de recrutement des sujets dans la recherche en pédiatrie : étude prospective multicentrique

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    Contexte. - Une enquĂȘte qualitative exploratoire a montrĂ© que le nombre de patients Ă©ligibles et sollicitĂ©s dans les essais en pĂ©diatrie Ă©tait peu objectivĂ© ainsi que les refus. Objectif. - Estimer le nombre de refus de participation des familles dans les essais en pĂ©diatrie et lier le taux de refus aux caractĂ©ristiques protocole, investigateur et patients. MatĂ©riel et mĂ©thodes. - Étude prospective multicentrique inter-CIC (rĂ©seau pĂ©diatrique) d'une cohorte de protocoles. Pour chaque sollicitation Ă  participer, des fiches patient, investigateur et protocole Ă©taient remplies. RĂ©sultats. - L'Ă©tude a Ă©tĂ© rĂ©alisĂ©e de dĂ©cembre 2005 Ă  septembre 2007 sur quatre centres et a inclus 45 protocoles : 32 Ă  promotion industrielle, 36 multicentriques, 19 essais cliniques, 33 avec prises de sang et six avec examens invasifs, 26 avec des dĂ©placements spĂ©cifiques et 14 des hospitalisations supplĂ©mentaires. Sur ces protocoles, 170 investigateurs Ă©taient rĂ©fĂ©rencĂ©s comme recruteurs et 86 (51 %) ont rĂ©pondu au questionnaire : Ăąge mĂ©dian 42 ans, sex-ratio de 1, 13 sont investigateurs principal, 32 responsables pour le CIC et 50 investigateurs associĂ©s, 20 percevaient une rĂ©tribution versĂ©e au service dans 80 % des cas. La charge de travail mĂ©diane par investigateur Ă©tait d'une heure par inclusion et 67 (78 %) bĂ©nĂ©ficiaient d'une aide d'une TEC. Au total, 1022 sollicitations ont Ă©tĂ© rĂ©alisĂ©es sur 36 protocoles (neuf protocoles n'ayant eu aucune sollicitation) et 334 refus (33 %) ont Ă©tĂ© enregistrĂ©s soit une mĂ©diane de 12 % (Q1Q3 : 0-28 %) de refus par protocole. Parmi les 36 protocoles, 16 n'ont enregistrĂ© aucun refus, reprĂ©sentant 147 sollicitations et les 20 autres protocoles ont eu un taux moyen de 38 % de refus. L'analyse explicative est en cours. Conclusion. - Le taux de refus de 12 % n'est pas diffĂ©rent de celui des essais adultes et semble dĂ©pendant du type d'Ă©tude. L'absence de sollicitation concerne 20 % des Ă©tudes
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