128 research outputs found

    Functional Analysis of Subunit e of the F\u3csub\u3e1\u3c/sub\u3eF\u3csub\u3eo\u3c/sub\u3e-ATP Synthase of the Yeast \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e: Importance of the N-Terminal Membrane Anchor Region

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    Mitochondrial F1Fo-ATP synthase complexes do not exist as physically independent entities but rather form dimeric and possibly oligomeric complexes in the inner mitochondrial membrane. Stable dimerization of two F1Fo-monomeric complexes involves the physical association of two membrane-embedded Fo-sectors. Previously, formation of the ATP synthase dimeric-oligomeric network was demonstrated to play a critical role in modulating the morphology of the mitochondrial inner membrane. In Saccharomyces cerevisiae, subunit e (Su e) of the Fo-sector plays a central role in supporting ATP synthase dimerization. The Su e protein is anchored to the inner membrane via a hydrophobic region located at its N-terminal end. The hydrophilic C-terminal region of Su e resides in the intermembrane space and contains a conserved coiled-coil motif. In the present study, we focused on characterizing the importance of these regions for the function of Su e. We created a number of C-terminal-truncated derivatives of the Su e protein and expressed them in the Su e null yeast mutant. Mitochondria were isolated from the resulting transformant strains, and a number of functions of Su e were analyzed. Our results indicate that the N-terminal hydrophobic region plays important roles in the Su e-dependent processes of mitochondrial DNA maintenance, modulation of mitochondrial morphology, and stabilization of the dimer-specific Fo subunits, subunits g and k. Furthermore, we show that the C-terminal coiled-coil region of Su e functions to stabilize the dimeric form of detergent-solubilized ATP synthase complexes. Finally, we propose a model to explain how Su e supports the assembly of the ATP synthase dimers-oligomers in the mitochondrial membrane

    Intranasal Delivery of a Methyllanthionine-Stabilized Galanin Receptor-2-Selective Agonist Reduces Acute Food Intake

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    The regulatory (neuro)peptide galanin is widely distributed in the central and peripheral nervous systems, where it mediates its effects via three G protein-coupled receptors (GAL(1-3)R). Galanin has a vast diversity of biological functions, including modulation of feeding behavior. However, the clinical application of natural galanin is not practicable due to its rapid in vivo breakdown by peptidases and lack of receptor subtype specificity. Much effort has been put into the development of receptor-selective agonists and antagonists, and while receptor selectivity has been attained to some degree, most ligands show overlapping affinity. Therefore, we aimed to develop a novel ligand with specificity to a single galanin receptor subtype and increased stability. To achieve this, a lanthionine amino acid was enzymatically introduced into a galanin-related peptide. The residue’s subsequent cyclization created a conformational constraint which increased the peptide’s receptor specificity and proteolytic resistance. Further exchange of certain other amino acids resulted in a novel methyllanthionine-stabilized galanin receptor agonist, a G1pE-T3N-S6A-G12A-methyllanthionine[13–16]-galanin-(1–17) variant, termed M89b. M89b has exclusive specificity for GAL(2)R and a prolonged half-life in serum. Intranasal application of M89b to unfasted rats significantly reduced acute 24 h food intake inducing a drop in body weight. Combined administration of M89b and M871, a selective GAL(2)R antagonist, abolished the anorexigenic effect of M89b, indicating that the effect of M89b on food intake is indeed mediated by GAL(2)R. This is the first demonstration of in vivo activity of an intranasally administered lanthipeptide. Consequently, M89b is a promising candidate for clinical application as a galanin-related peptide-based therapeutic. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13311-021-01155-x

    Neuropsychological development in adolescents: Longitudinal associations with white matter microstructure

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    Important neuropsychological changes during adolescence coincide with the maturation of white matter microstructure. Few studies have investigated the association between neuropsychological development and white matter maturation longitudinally. We aimed to characterize developmental trajectories of inhibition, planning, emotion recognition and risk-taking and examine whether white matter microstructural characteristics were associated with neuropsychological development above and beyond age. In an accelerated longitudinal cohort design, n 1/4 112 healthy adolescents between ages 9 and 16 underwent cognitive assessment and diffusion MRI over three years. Fractional anisotropy (FA) and mean diffusivity (MD) were extracted for major white matter pathways using an automatic probabilistic reconstruction technique and mixed models were used for statistical analyses. Inhibition, planning and emotion recognition performance improved linearly across adolescence. Risk-taking developed in a quadratic fashion, with stable performance between 9 and 12 and an increase between ages 12 and 16. Including cingulum and superior longitudinal fasciculus FA slightly improved model fit for emotion recognition across age. We found no evidence that FA or MD were related to inhibition, planning or risk-taking across age. Our results challenge the additional value of white matter microstructure to explain neuropsychological development in healthy adolescents, but more longitudinal research with large datasets is needed to identify the potential role of white matter microstructure in cognitive development

    Trichoderma G protein-coupled receptors: functional characterisation of a cAMP receptor-like protein from Trichoderma atroviride

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    Gα subunits act to regulate vegetative growth, conidiation, and the mycoparasitic response in Trichoderma atroviride. To extend our knowledge on G protein signalling, we analysed G protein-coupled receptors (GPCRs). As the genome sequence of T. atroviride is not publicly available yet, we carried out an in silico exploration of the genome database of the close relative T. reesei. Twenty genes encoding putative GPCRs distributed over eight classes and additional 35 proteins similar to the Magnaporthe grisea PTH11 receptor were identified. Subsequently, four T. atroviride GPCR-encoding genes were isolated and affliated to the cAMP receptor-like family by phylogenetic and topological analyses. All four genes showed lowest expression on glycerol and highest mRNA levels upon carbon starvation. Transcription of gpr3 and gpr4 responded to exogenously added cAMP and the shift from liquid to solid media. gpr3 mRNA levels also responded to the presence of fungal hyphae or cellulose membranes. Further characterisation of mutants bearing a gpr1-silencing construct revealed that Gpr1 is essential for vegetative growth, conidiation and conidial germination. Four genes encoding the first GPCRs described in Trichoderma were isolated and their expression characterized. At least one of these GPCRs is important for several cellular processes, supporting the fundamental role of G protein signalling in this fungus

    Mitochondrial Haplogroups and Control Region Polymorphisms in Age-Related Macular Degeneration: A Case-Control Study

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    Background: Onset and development of the multifactorial disease age-related macular degeneration (AMD) are highly interrelated with mitochondrial functions such as energy production and free radical turnover. Mitochondrial dysfunction and overproduction of reactive oxygen species may contribute to destruction of the retinal pigment epithelium, retinal atrophy and choroidal neovascularization, leading to AMD. Consequently, polymorphisms of the mitochondrial genome (mtDNA) are postulated to be susceptibility factors for this disease. Previous studies from Australia and the United States detected associations of mitochondrial haplogroups with AMD. The aim of the present study was to test these associations in Middle European Caucasians. Methodology/Principal Findings: Mitochondrial haplogroups (combinations of mtDNA polymorphisms) and mitochondrial CR polymorphisms were analyzed in 200 patients with wet AMD (choroidal neovascularization, CNV), in 66 patients with dry AMD, and in 385 controls from Austria by means of multiplex primer extension analysis and sequencing, respectively. In patients with CNV, haplogroup H was found to be significantly less frequent compared to controls, and haplogroup J showed a trend toward a higher frequency compared to controls. Five CR polymorphisms were found to differ significantly in the two study populations compared to controls, and all, except one (T152C), are linked to those haplogroups. Conclusions/Significance: It can be concluded that haplogroup J is a risk factor for AMD, whereas haplogroup H seems t

    Identifying core MRI sequences for reliable automatic brain metastasis segmentation

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    BACKGROUND Many automatic approaches to brain tumor segmentation employ multiple magnetic resonance imaging (MRI) sequences. The goal of this project was to compare different combinations of input sequences to determine which MRI sequences are needed for effective automated brain metastasis (BM) segmentation. METHODS We analyzed preoperative imaging (T1-weighted sequence ± contrast-enhancement (T1/T1-CE), T2-weighted sequence (T2), and T2 fluid-attenuated inversion recovery (T2-FLAIR) sequence) from 339 patients with BMs from seven centers. A baseline 3D U-Net with all four sequences and six U-Nets with plausible sequence combinations (T1-CE, T1, T2-FLAIR, T1-CE + T2-FLAIR, T1-CE + T1 + T2-FLAIR, T1-CE + T1) were trained on 239 patients from two centers and subsequently tested on an external cohort of 100 patients from five centers. RESULTS The model based on T1-CE alone achieved the best segmentation performance for BM segmentation with a median Dice similarity coefficient (DSC) of 0.96. Models trained without T1-CE performed worse (T1-only: DSC = 0.70 and T2-FLAIR-only: DSC = 0.73). For edema segmentation, models that included both T1-CE and T2-FLAIR performed best (DSC = 0.93), while the remaining four models without simultaneous inclusion of these both sequences reached a median DSC of 0.81-0.89. CONCLUSIONS A T1-CE-only protocol suffices for the segmentation of BMs. The combination of T1-CE and T2-FLAIR is important for edema segmentation. Missing either T1-CE or T2-FLAIR decreases performance. These findings may improve imaging routines by omitting unnecessary sequences, thus allowing for faster procedures in daily clinical practice while enabling optimal neural network-based target definitions

    Prevalences of cardiometabolic risk and lifestyle factors in young parents: evidence from a German birth cohort study

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    Background Studies show that parents significantly impact their children’s health through their cardiometabolic risk profile and health behavior. There is only little information about the prevalence of cardiometabolic risk factors and lifestyle factors among new parents yet. The aims of this study are therefore to evaluate the prevalences of cardiometabolic risk factors in parents of infants in Germany and to examine their lifestyle and health behavior. Methods In the KUNO-Kids health study, an ongoing birth cohort, parents (n = 930 mothers and 769 fathers) were asked about cardiometabolic risk factors (obesity/hypertension/type 2 diabetes mellitus) and lifestyle factors (dietary/sports/smoking habits/alcohol consumption) during the first year after the birth of their children via questionnaires. Chi-square as well as fisher exact tests were conducted to analyse associations between lifestyle factors and cardiometabolic risk factors. Results 34.2% of mothers and 58.5% of fathers were overweight or obese. In 11.8% of the families, at least one parent suffered from hypertension, in 2.4% from type 2 diabetes mellitus. One year after delivery, 8.5% of mothers were smoking, 6.9% showed a risky alcohol consumption (> 10 g/d). 16.0% of fathers were smoking 4 weeks after childbirth, 10.7% showed risky alcohol consumption (> 20 g/d). 21.6% of mothers carried out sports activity for more than 2 h a week then. Parental hypertension was linked to a higher prevalence of risky alcohol consumption, obesity to a lower prevalence of daily fruits consumption. Conclusions Cardiometabolic risk factors were widespread among new parents with obesity and overweight having the highest prevalences. A considerable number of parents also practiced an unhealthy lifestyle showing that there is potential for improvement to promote the healthy development of their children

    Transgene × Environment Interactions in Genetically Modified Wheat

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    BACKGROUND: The introduction of transgenes into plants may cause unintended phenotypic effects which could have an impact on the plant itself and the environment. Little is published in the scientific literature about the interrelation of environmental factors and possible unintended effects in genetically modified (GM) plants. METHODS AND FINDINGS: We studied transgenic bread wheat Triticum aestivum lines expressing the wheat Pm3b gene against the fungus powdery mildew Blumeria graminis f.sp. tritici. Four independent offspring pairs, each consisting of a GM line and its corresponding non-GM control line, were grown under different soil nutrient conditions and with and without fungicide treatment in the glasshouse. Furthermore, we performed a field experiment with a similar design to validate our glasshouse results. The transgene increased the resistance to powdery mildew in all environments. However, GM plants reacted sensitive to fungicide spraying in the glasshouse. Without fungicide treatment, in the glasshouse GM lines had increased vegetative biomass and seed number and a twofold yield compared with control lines. In the field these results were reversed. Fertilization generally increased GM/control differences in the glasshouse but not in the field. Two of four GM lines showed up to 56% yield reduction and a 40-fold increase of infection with ergot disease Claviceps purpurea compared with their control lines in the field experiment; one GM line was very similar to its control. CONCLUSIONS: Our results demonstrate that, depending on the insertion event, a particular transgene can have large effects on the entire phenotype of a plant and that these effects can sometimes be reversed when plants are moved from the glasshouse to the field. However, it remains unclear which mechanisms underlie these effects and how they may affect concepts in molecular plant breeding and plant evolutionary ecology
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