Seed Production Affects Maternal Growth and Senescence in Arabidopsis

Correlative control (influence of one organ over another organ) of seeds over maternal growth is one of the most obvious phenotypic expressions of the trade-off between growth and reproduction. However, the underlying molecular mechanisms are largely unknown. Here, we characterize the physiological and molecular effects of correlative inhibition by seeds on Arabidopsis (Arabidopsis thaliana) inflorescences, i.e. global proliferative arrest (GPA) during which all maternal growth ceases upon the production of a given number of seeds. We observed transcriptional responses to growth- and branching-inhibitory hormones, and low mitotic activity in meristems upon GPA, but found that meristems retain their identity and proliferative potential. In shoot tissues, we detected the induction of stress- and senescence-related gene expression upon fruit production and GPA, and a drop in chlorophyll levels, suggestive of altered source-sink relationships between vegetative shoot and reproductive tissues. Levels of shoot reactive oxygen species, however, strongly decreased upon GPA, a phenomenon that is associated with bud dormancy in some perennials. Indeed, gene expression changes in arrested apical inflorescences after fruit removal resembled changes observed in axillary buds following release from apical dominance. This suggests that GPA represents a form of bud dormancy, and that dominance is gradually transferred from growing inflorescences to maturing seeds, allowing offspring control over maternal resources, simultaneously restricting offspring number. This would provide a mechanistic explanation for the constraint between offspring quality and quantity

Areal Surface Roughness Optimization of Maraging Steel Parts Produced by Hybrid Additive Manufacturing

We report on an experimental study and statistical optimization of the surface roughness using design of experiments and the Taguchi method for parts made of 1.2709 maraging steel. We employ a hybrid additive manufacturing approach that combines additive manufacturing by selective laser melting with subtractive manufacturing using milling in an automated process within a single machine. Input parameters such as laser power, scan speed, and hatching distance have been varied in order to improve surface quality of unmachined surfaces. Cutting speed, feed per tooth, and radial depth of cut have been varied to optimize surface roughness of the milled surfaces. The surfaces of the samples were characterized using 3D profilometry. Scan speed was determined as the most important parameter for non-machined surfaces; radial depth of cut was found to be the most significant parameter for milled surfaces. Areal surface roughness S a could be reduced by up to 40 for unmachined samples and by 23 for milled samples as compared to the prior state of the art

Development and evaluation of three-dimensional transfers to depict skin conditions in simulation-based education

Modern medical moulages are becoming increasingly important in simulation-based health professions education. Their lifelikeness is important so that simulation engagement is not disrupted while their standardization is crucial in high-stakes exams. This report describes in detail how three-dimensional transfers are developed and produced so that educators will be able to develop their own. In addition, evaluation findings and lessons learnt from deploying transfers in summative assessments are shared. Step-by-step instructions are given for the creation and application of transfers, including materials and photographic visualizations. We also examined feedback on 10 exam stations (out of a total of 81) with self-developed three-dimensional transfers and complement this with additional lessons learnt. By the time of submission, the authors successfully developed and deployed over 40 different three-dimensional transfers representing different clinical findings in high-stakes exams using the techniques explained in this article or variations thereof. Feedback from students and examiners after completing the OSCE is predominantly positive, with lifelikeness being the quality most often commented upon. Caveats derived from feedback and own experiences are included. The step-by-step approach reported can be adapted and replicated by healthcare educators to build their own three-dimensional transfers. This should widen the scope and the lifelikeness of their simulations. At the same time we propose that this level of lifelikeness should be expected by learners as not to disrupt simulation engagement. Our evaluation of their use in high-stakes assessments suggests they are both useful and accepted

Supplemental Data: Table S1

Contains supplemental data (Table S1) to the publication "Use of Bacillus subtilis spores in printing and additive manufacturing as a robust, DNA‑based anti‑counterfeiting & identification feature: Stresses, processing and evaluation". Contents: Results of PCR and gel electrophoresis,

Tissue-specific effects of exercise as NAD + -boosting strategy: Current knowledge and future perspectives.

Nicotinamide adenine dinucleotide (NAD + ) is an evolutionarily highly conserved coenzyme with multi-faceted cell functions, including energy metabolism, molecular signaling processes, epigenetic regulation, and DNA repair. Since the discovery that lower NAD + levels are a shared characteristic of various diseases and aging per se, several NAD + -boosting strategies have emerged. Other than pharmacological and nutritional approaches, exercise is thought to restore NAD + homeostasis through metabolic adaption to chronically recurring states of increased energy demand. In this review we discuss the impact of acute exercise and exercise training on tissue-specific NAD + metabolism of rodents and humans to highlight the potential value as NAD + -boosting strategy. By interconnecting results from different investigations, we aim to draw attention to tissue-specific alterations in NAD + metabolism and the associated implications for whole-body NAD + homeostasis. Acute exercise led to profound alterations of intracellular NAD + metabolism in various investigations, with the magnitude and direction of changes being strongly dependent on the applied exercise modality, cell type, and investigated animal model or human population. Exercise training elevated NAD + levels and NAD + metabolism enzymes in various tissues. Based on these results, we discuss molecular mechanisms that might connect acute exercise-induced disruptions of NAD + /NADH homeostasis to chronic exercise adaptions in NAD + metabolism. Taking this hypothesis-driven approach, we hope to inspire future research on the molecular mechanisms of exercise as NAD + -modifying lifestyle intervention, thereby elucidating the potential therapeutic value in NAD + -related pathologies

The Plant Sesquiterpene Nootkatone Efficiently Reduces Heterodera schachtii Parasitism by Activating Plant Defense

Plant parasitic nematodes, including the beet cyst nematode Heterodera schachtii, constitute a devastating problem for crops worldwide. The limited availability of sustainable management options illustrates the need for new eco-friendly control means. Plant metabolites represent an invaluable source of active compounds for the discovery of such novel antagonistic agents. Here, we evaluated the impact of eight plant terpenoids on the H. schachtii parasitism of Arabidopsis thaliana. None of the metabolites affected the plant development (5 or 10 ppm). Nootkatone decreased the number of adult nematodes on A. thaliana to 50%, with the female nematodes being smaller compared to the control. In contrast, three other terpenoids increased the parasitism and/or female size. We discovered that nootkatone considerably decreased the number of nematodes that penetrated A. thaliana roots, but neither affected the nematode viability or attraction to plant roots, nor triggered the production of plant reactive oxygen species or changed the plant’s sesquiterpene profile. However, we demonstrated that nootkatone led to a significant upregulation of defense-related genes involved in salicylic and jasmonic acid pathways. Our results indicate that nootkatone is a promising candidate to be developed into a novel plant protection agent acting as a stimulator of plant immunity against parasitic nematode