Strength of interactions in the Notch gene regulatory network determines patterning and fate in the notochord

Development of multicellular organisms requires the generation of gene expression patterns that determines cell fate and organ shape. Groups of genetic interactions known as Gene Regulatory Networks (GRNs) play a key role in the generation of such patterns. However, how the topology and parameters of GRNs determine patterning in vivo remains unclear due to the complexity of most experimental systems. To address this, we use the zebrafish notochord, an organ where coin-shaped precursor cells are initially arranged in a simple unidimensional geometry. These cells then differentiate into vacuolated and sheath cells. Using newly developed transgenic tools together with in vivo imaging, we identify jag1a and her6/her9 as the main components of a Notch GRN that generates a lateral inhibition pattern and determines cell fate. Making use of this experimental system and mathematical modeling we show that lateral inhibition patterning is promoted when ligand-receptor interactions are stronger within the same cell than in neighboring cells. Altogether, we establish the zebrafish notochord as an experimental system to study pattern generation, and identify and characterize how the properties of GRNs determine self-organization of gene patterning and cell fate

Responsabilidad administrativa ambiental de los particulares en Colombia. Un análisis desde sus elementos

La responsabilidad administrativa por los daños al medio ambiente en Colombia está contenida en la Ley 1333 de 2009, que tiene como finalidad, establecer el marco normativo sancionador que regule las infracciones a las normas ambientales y, además, los daños ocasionados a los recursos naturales. Para efectos de determinar la sanción administrativa ambiental, esta norma remite a los criterios establecidos para configurar la responsabilidad civil extracontractual. No obstante, este régimen sancionador ha sido ampliamente criticado desde lo procedimental, al remitir a las autoridades ambientales, a los elementos de la responsabilidad civil extracontractual para determinar la sanción administrativa. Por tanto, se hace necesario analizar, a partir de la naturaleza y elementos de la responsabilidad, tanto en el derecho privado como en el derecho público, si el régimen sancionatorio ambiental se articula con alguno de estos sectores, o por el contrario se trata de un régimen especial con una naturaleza jurídica distinta.#ResponsabilidadAdministrativaAmbientaldministrative liability for damage to the environment in Colombia is contained in Law 1333 of 2009, the purpose of which is to establish a sanctioning regulatory framework, which regulates infractions of environmental regulations, and, in addition, damage caused to natural resources. For purposes of determining the environmental administrative sanction, this standard refers to the criteria established to configure extra-contractual civil liability. However, this sanctioning regime has been widely criticized from the procedural point of view, referring to the environmental authorities to the elements of extra-contractual civil liability for the purpose of determining the administrative sanction. That is why it is necessary to analyze from the nature and elements of liability both in private law and in public law and determine if the environmental sanctioning regime is articulated with any of these sectors, or on the contrary it is of a special regime with a different legal nature

Fused and unzipped carbon nanotubes, electrochemically treated, for selective determination of dopamine and serotonin

Glassy carbon electrodes (GC) were modified with multiwalled carbon nanotubes (MWCNT/GC) and electrochemically treated first by applying an oxidation potential and then a reduction potential. The resulting electrodes were characterized via scanning electron microscopy, Raman spectroscopy, energy dispersive spectroscopy, and electrochemical techniques, particularly cyclic voltammetry using the redox probes Fe(CN)6 3− /4- and Ru(NH3)2+/3+ and electrochemical impedance spectroscopy using Fe(CN)6 3− /4-. These modified electrodes showed an electrochemical determination selective for dopamine (DA) and serotonin (5HT) in the presence of ascorbic acid (AA) and uric acid (UA), simultaneously measured, with a high reproducibility (an RSD of 1.7% for DA and 1.6% for 5HT) and a limit of detection (LOD) of 235 nmol L−1 for DA and 460 nmol L−1 for 5HT. The GC electrodes modified with oxidized MWCNT, subsequently reduced, showed higher selectivity towards the oxidation of DA and 5HT compared with GC bare electrodes or modified with MWCNT or oxidized MWCNT.Fil: Bonetto, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Muñoz, Fernando Francisco. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Diz, Virginia Emilse. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Sacco, Natalia Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Corton, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

Control of Directed Cell Migration In Vivo by Membrane-to-Cortex Attachment

Analysis of cell migration in vivo combined with biophysical measurements reveals how membrane-to-cortex attachment fine-tunes the type of protrusions formed by cells and, as a consequence, controls directed migration during zebrafish gastrulation

Steering cell migration by alternating blebs and actin-rich protrusions.

BACKGROUND: High directional persistence is often assumed to enhance the efficiency of chemotactic migration. Yet, cells in vivo usually display meandering trajectories with relatively low directional persistence, and the control and function of directional persistence during cell migration in three-dimensional environments are poorly understood. RESULTS: Here, we use mesendoderm progenitors migrating during zebrafish gastrulation as a model system to investigate the control of directional persistence during migration in vivo. We show that progenitor cells alternate persistent run phases with tumble phases that result in cell reorientation. Runs are characterized by the formation of directed actin-rich protrusions and tumbles by enhanced blebbing. Increasing the proportion of actin-rich protrusions or blebs leads to longer or shorter run phases, respectively. Importantly, both reducing and increasing run phases result in larger spatial dispersion of the cells, indicative of reduced migration precision. A physical model quantitatively recapitulating the migratory behavior of mesendoderm progenitors indicates that the ratio of tumbling to run times, and thus the specific degree of directional persistence of migration, are critical for optimizing migration precision. CONCLUSIONS: Together, our experiments and model provide mechanistic insight into the control of migration directionality for cells moving in three-dimensional environments that combine different protrusion types, whereby the proportion of blebs to actin-rich protrusions determines the directional persistence and precision of movement by regulating the ratio of tumbling to run times.This work was supported by the Max Planck Society, the Medical Research Council UK (core funding to the MRC LMCB), and by grants from the Polish Ministry of Science and Higher Education (454/N-MPG/2009/0) to EKP, the Deutsche Forschungsgemeinschaft (HE 3231/6-1 and PA 1590/1-1) to CPH and EKP, a A*Star JCO career development award (12302FG010) to WY and a Damon Runyon fellowship award to ADM (DRG 2157-12). This work was also supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001317), the UK Medical Research Council (FC001317), and the Wellcome Trust (FC001317) to G

Guía sobre las enfermedades fúngicas de la madera de la vid

Reunión Grupo de Trabajo de experimentación en viticultura y enología. 34ª Reunión: Centro de Transferencia Agroalimentaria: Gobierno de Aragón: Zaragoza: 10 y 11 de abril de 2019. ANEXOLas enfermedades fúngicas de la madera de la vid (EMV) son uno de los retos más importantes que actualmente debe afrontar la viticultura en todo el mundo para su sostenibilidad. Estas enfermedades causan daños severos en el viñedo todos los años y su incidencia está creciendo rápidamente en todos los países productores (De la Fuente et al., 2016). Las EMV están causadas por varios hongos patógenos que viven y colonizan la madera de los órganos perennes, causando necrosis y decoloración de la madera, infecciones vasculares, y descomposición esponjosa seca. Las viñas afectadas muestran, externamente, un decaimiento general y progresivo (retraso de la brotación, yemas muertas, decaimiento de la planta, parada del desarrollo, clorosis, apoplejía, etc.), generalmente asociado a unos síntomas foliares acordes a las diferentes enfermedades, que inicialmente pueden causar pérdida de productividad y eventualmente la muerte de las plantas (Gramaje et al., 2018). En España se estima una media del 3% de plantas afectadas por EMV, aunque existen plantaciones recién establecidas en las que su incidencia podría superar el 20%, generando pérdidas económicas anuales muy elevadas (De la Fuente et al., 2016). Según estimaciones recientes, el coste anual de replantar el 1% de vid del cultivar Tempranillo en La Rioja debido a las EMV asciende a 7,16 millones de euros anuales (Martínez-Diz et al., 2019). En Francia, se estima que aproximadamente un 12% de los viñedos son improductivos debido a las EMV, causando unas pérdidas anuales de 1 billón de euros (Lorch, 2014)

Quantifying cellular mechanics and adhesion in renal tubular injury using single cell force spectroscopy

Abstract Tubulointerstitial fibrosis represents the major underlying pathology of diabetic nephropathy where loss of cell-to-cell adhesion is a critical step. To date, research has predominantly focussed on the loss of cell surface molecular binding events that include altered protein ligation. In the current study, atomic force microscopy single cell force spectroscopy (AFM- SCFS) was used to quantify changes in cellular stiffness and cell adhesion in TGF-β1 treated kidney cells of the human proximal tubule (HK2). AFM indentation of TGF-β1 treated HK2 cells showed a significant increase (42%) in the Elastic modulus (stiffness) compared to control. Fluorescence microscopy confirmed that increased cell stiffness is accompanied by reorganization of the cytoskeleton. The corresponding changes in stiffness, due to F-actin rearrangement, affected the work of detachment by changing the separation distance between two adherent cells. Overall, our novel data quantitatively demonstrate a correlation between cellular elasticity, adhesion and early morphologic/phenotypic changes associated with tubular injury

Quantitative investigation of calcimimetic R568 on beta-cell adhesion and mechanics using AFM single-cell force spectroscopy

In this study we use a novel approach to quantitatively investigate mechanical and interfacial properties of clonal b-cells using AFM-Single Cell Force Spectroscopy (SCFS). MIN6 cells were incubated for 48 h with 0.5 mMCa2+ ± the calcimimetic R568 (1 lM). AFM-SCFS adhesion and indentation experiments were performed by using modified tipless cantilevers. Hertz contact model was applied to analyse force–displacement (F–d) curves for determining elastic or Young’s modulus (E). Our results show CaSR-evoked increases in cell-to-cell adhesion parameters and E modulus of single cells, demonstrating that cytomechanics have profound effects on cell adhesion characterization

ACTG-HIV symptoms changes in patients switched to RPV/FTC/TDF due to previous intolerance to CART. Interim analysis of the PROSTR study

Introduction: Tolerability and convenience are crucial aspects for the long-term success of combined antiretroviral therapy (cART). The aim of this study was to investigate the impact in routine clinical practice of switching to the single tablet regimen (STR) RPV/FTC/TDF in patients with intolerance to previous cART, in terms of patients’ well-being, assessed by several validated measures. Methods: Prospective, multicenter study. Adult HIV-infected patients with viral load under 1.000 copies/mL while receiving a stable ART for at least the last three months and switched to RPV/FTC/TDF due to intolerance of previous regimen, were included. Analyses were performed by ITT. Presence/magnitude of symptoms (ACTG-HIV Symptom Index), quality of life (EQ-5D, EUROQoL & MOS-HIV), adherence (SMAQ), preference of treatment and perceived ease of medication (ESTAR) through 48 weeks were performed. Results: Interim analysis of 125 patients with 16 weeks of follow up was performed. 100 (80%) were male, mean age 46 years. Mean CD4 at baseline was 629.59307.29 and 123 (98.4%) had viral load B50 copies/mL; 15% were HCV co-infected. Ninety two (73.6%) patients switched from a NNRTI (84.8% from EFV/FTC/TDF) and 33 (26.4%) from a PI/r. The most frequent reasons for switching were psychiatric disorders (51.2%), CNS adverse events (40.8%), gastrointestinal (19.2%) and metabolic disorders (19.2%). At the time of this analysis (week 16), four patients (3.2%) discontinued treatment: one due to adverse events, two virologic failures and one with no data. A total of 104 patients (83.2%) were virologically suppressed (B50 copies/mL). The average degree of discomfort in the ACTG-HIV Symptom Index significantly decreased from baseline (21915.55) to week 4 (10.89912.36) & week 16 (10.81912.62), pB0.001. In all the patients, quality of life tools showed a significant benefit in wellbeing of the patients (Table 1). Adherence to therapy significantly and progressively increased (SMAQ) from baseline (54.4%) to week 4 (68%), pB0.001 and to week 16 (72.0%), pB0.001. Conclusions: Switching to RPV/FTC/TDF from another ARV regimen due to toxicity, significantly improved the quality of life of HIV-infected patients, both in mental and physical components, and improved adherence to therapy while maintaining a good immune and virological response

Membrane tension controls adhesion positioning at the leading edge of cells

Cell migration is dependent on adhesion dynamics and actin cytoskeleton remodeling at the leading edge. These events may be physically constrained by the plasma membrane. Here, we show that the mechanical signal produced by an increase in plasma membrane tension triggers the positioning of new rows of adhesions at the leading edge. During protrusion, as membrane tension increases, velocity slows, and the lamellipodium buckles upward in a myosin II-independent manner. The buckling occurs between the front of the lamellipodium, where nascent adhesions are positioned in rows, and the base of the lamellipodium, where a vinculin-dependent clutch couples actin to previously positioned adhesions. As membrane tension decreases, protrusion resumes and buckling disappears, until the next cycle. We propose that the mechanical signal of membrane tension exerts upstream control in mechanotransduction by periodically compressing and relaxing the lamellipodium, leading to the positioning of adhesions at the leading edge of cells