The regulation of mitotic spindle positioning and orientation is central to the morphogenesis of developing embryos and tissues. In many multicellular contexts, cell geometry has been shown to have a major influence on spindle positioning, with spindles that commonly align along the longest cell shape axis. To date, however, we still lack an understanding of how the nature and amplitude of intracellular forces that position, orient, or hold mitotic spindles depend on cell geometry.
View Article and Find Full Text PDFMost high-yielding crops are susceptible to abiotic and biotic stresses, making them particularly vulnerable to the potential effects of climate change. A possible alternative is to accelerate the domestication of wild plants that are already tolerant to harsh conditions and to increase their yields by methods such as gene editing. We foresee that crops' wild progenitors could potentially compete with the resulting de novo domesticated plants, reducing yields.
View Article and Find Full Text PDFAs cells organize spatially or divide, they translocate many micron-scale organelles in their cytoplasm. These include endomembrane vesicles, nuclei, microtubule asters, mitotic spindles, or chromosomes. Organelle motion is powered by cytoskeleton forces but is opposed by viscoelastic forces imparted by the surrounding crowded cytoplasm medium.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2023
Many studies of cytoplasm rheology have focused on small components in the submicrometer scale. However, the cytoplasm also baths large organelles like nuclei, microtubule asters, or spindles that often take significant portions of cells and move across the cytoplasm to regulate cell division or polarization. Here, we translated passive components of sizes ranging from few up to ~50 percents of the cell diameter, through the vast cytoplasm of live sea urchin eggs, with calibrated magnetic forces.
View Article and Find Full Text PDFDodder ( Yunck.) is one of the most devastating parasitic plants, which reduces quantity and quality of crops. The inhibitory effect of catnip ( Benth.
View Article and Find Full Text PDFPerennial grain crops could make a valuable addition to sustainable agriculture, potentially even as an alternative to their annual counterparts. The ability of perennials to grow year after year significantly reduces the number of agricultural inputs required, in terms of both planting and weed control, while reduced tillage improves soil health and on-farm biodiversity. Presently, perennial grain crops are not grown at large scale, mainly due to their early stages of domestication and current low yields.
View Article and Find Full Text PDFSustainable agriculture in the future will depend on crops that are tolerant to biotic and abiotic stresses, require minimal input of water and nutrients and can be cultivated with a minimal carbon footprint. Wild plants that fulfill these requirements abound in nature but are typically low yielding. Thus, replacing current high-yielding crops with less productive but resilient species will require the intractable trade-off of increasing land area under cultivation to produce the same yield.
View Article and Find Full Text PDFThe Mildew Resistance Locus O (MLO) promotes both symbiosis and biotrophic interactions with fungi. MLO disruption results in powdery mildew resistance but is associated with growth defects. New research by Li et al.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2022
We characterize the bundle properties for three different strains of B. subtilis bacteria with various numbers of flagella. Our study reveals that, surprisingly, the number of bundles is independent of the number of flagella, and the formation of three bundles is always the most frequent case.
View Article and Find Full Text PDFSmall post-translationally modified peptides are important signalling components of plant defence responses against phytopathogens, acting as both positive and negative modulators. PAMP-INDUCED SECRETED PEPTIDE (PIP) 1 and 2 have been shown to amplify plant immunity. Here we investigate the role of the related peptide PIP3 in the regulation of immune response in Arabidopsis.
View Article and Find Full Text PDFPeritrichous bacteria synchronize and bundle their flagella to actively swim, while disruption of the bundle leads to a slow motility phase with a weak propulsion. It is still not known whether the number of flagella represents an evolutionary adaptation toward optimizing bacterial navigation. We study the swimming dynamics of differentially flagellated strains in a quasi-two-dimensional system.
View Article and Find Full Text PDFPhosphorus, an essential element for all living organisms, is a limiting nutrient in many regions of the ocean due to its fast recycling. Changes in phosphate (Pi) availability in aquatic systems affect diatom growth and productivity. We investigated the early adaptive mechanisms in the marine diatom Phaeodactylum tricornutum to P deprivation using a combination of transcriptomics, metabolomics, physiological and biochemical experiments.
View Article and Find Full Text PDFSmall signalling peptides have emerged as important cell to cell messengers in plant development and stress responses. However, only a few of the predicted peptides have been functionally characterized. Here, we present functional characterization of two members of the IDA-LIKE (IDL) peptide family in Arabidopsis thaliana, IDL6 and IDL7.
View Article and Find Full Text PDFInsight into crumpling or compaction of one-dimensional objects is important for understanding biopolymer packaging and designing innovative technological devices. By compacting various types of wires in rigid confinements and characterizing the morphology of the resulting crumpled structures, here, we report how friction, plasticity and torsion enhance disorder, leading to a transition from coiled to folded morphologies. In the latter case, where folding dominates the crumpling process, we find that reducing the relative wire thickness counter-intuitively causes the maximum packing density to decrease.
View Article and Find Full Text PDFBackground: The licensed intravenous acetylcysteine regimen for treating paracetamol overdose in most countries uses three separate infusions over 21 h. This complex regimen, requiring different infusion concentrations and rates, has been associated with administration errors. The aim of the present study was to assess the extent of administration delays occurring during this acetylcysteine regimen.
View Article and Find Full Text PDFContext: Recreational use of Synthetic Cannabinoid Receptors Agonists (SCRAs) has become increasingly common in many countries and may cause severe toxic effects.
Objective: To describe the clinical features of toxicity in seven men after analytically confirmed exposure to MDMB-CHMICA, a recently described indole-based SCRA.
Materials And Methods: Clinical information and biological samples (blood, urine) were collected from patients with severe toxicity after suspected use of novel psychoactive substances.
Context: Toxicity from the use of synthetic cannabinoid receptor agonists (SCRAs) has been encountered increasingly frequent in many countries.
Objective: To characterise presentation rates, demographic profiles and reported clinical features for users of SCRAs referred by health professionals in the United Kingdom to the National Poisons Information Service (NPIS), to compare reported toxicity between commonly used branded products, and to examine the impact of legal control measures on enquiry numbers.
Methods: NPIS telephone enquiry records were searched for SCRA-related terms for the 8-year period 1st January 2007 to 31st December 2014, consolidating multiple enquiries about the same case into a single record.
Peptide ligands play crucial roles in the life cycle of plants by modulating the innate immunity against pathogens and regulating growth and developmental processes. One well-studied example is INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which controls floral organ abscission and lateral root emergence in Arabidopsis thaliana. IDA belongs to a family of five additional IDA-LIKE (IDL) members that have all been suggested to be involved in regulation of Arabidopsis development.
View Article and Find Full Text PDFIn this paper we study the ordered packing of wires in a sphere. We propose an analytical model and compare the model predictions with the results of our experiments and simulations for the maximum packing fraction, the number of formed coils, the fractal dimension, and bending energy. We show that the relative system size [i.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
July 2011
We study the dynamics of instability and pattern formation in a slender elastic thread that is continuously fed onto a surface moving at constant speed V in its own plane. As V is decreased below a critical value V(c), the steady "dragged catenary" configuration of the thread becomes unstable to sinusoidal meanders and thence to a variety of more complex patterns including biperiodic meanders, figures of 8, "W," "two-by-one," and "two-by-two" patterns, and double coiling. Laboratory experiments are performed to determine the phase diagram of these patterns as a function of V, the thread feeding speed U, and the fall height H.
View Article and Find Full Text PDFBackground: Levosimendan is an inotropic agent used in the treatment of heart failure. It is a myocardial calcium sensitizer, binding to cardiac troponin-C, and a vascular K+ATP-channel agonist producing peripheral vasodilatation.
Aims: To assess the effect of levosimendan on cardiac output (CO), blood pressure (BP), and heart rate (HR) in a rodent model of severe verapamil poisoning.