RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica: Repression of flhDC transcription by a RcsB-RflM complex

The bacterial flagellum enables directed movement of Salmonella enterica towards favorable conditions in liquid environments. Regulation of flagellar synthesis is tightly controlled by various environmental signals at transcriptional and post- transcriptional levels. The flagellar master regulator FlhD₄C₂ resides on top of the flagellar transcriptional hierarchy and is under autogenous control by FlhD₄C₂- dependent activation of the repressor rflM. The inhibitory activity of RflM depends on the presence of RcsB, the response regulator of the RcsCDB phosphorelay system. In this study, we elucidated the molecular mechanism of RflM- dependent repression of flhDC. We show that RcsB and RflM form a heterodimer that coordinately represses flhDC transcription independent of RcsB phosphorylation. RcsB-RflM complex binds to a RcsB box downstream the P1 transcriptional start site of the flhDC promoter with increased affinity compared to RcsB in the absence of RflM. We propose that RflM stabilizes binding of unphosphorylated RcsB to the flhDC promoter in absence of environmental cues. Thus, RflM is a novel auxiliary regulatory protein that mediates target specificity of RcsB for flhDC repression. The cooperative action of the RcsB-RflM repressor complex allows Salmonella to fine-tune initiation of flagellar gene expression and adds another level to the complex regulation of flagellar synthesis

Analysis of SWFs' strategies in the energy sector: a comparison with private equity investments

LAUREA MAGISTRALECon la profonda trasformazione in atto nei mercati energetici globali, il ruolo degli investitori istituzionali di lungo termine nello sviluppo di un futuro energetico sostenibile si fa sempre più strategico. Questa tesi analizza in che modo i Sovereign Wealth Funds (SWF) e i fondi di Private Equity (PE) affrontano gli investimenti nel settore energetico, con l’obiettivo di identificare logiche di investimento, differenze strutturali e potenziali best practice. A tal fine, viene adottato un doppio approccio metodologico: il Nine-Dimension SWF Assessment Framework, che offre una visione completa della struttura istituzionale e dell’orientamento strategico dei fondi sovrani, e la IRFA Taxonomy (Investor Objective, Resource Fit, Advantage Clusters), utilizzata per classificare oltre 1.500 transazioni energetiche sulla base dell’obiettivo d’investimento, dell’allineamento geografico e delle condizioni di vantaggio contestuale. Applicando questi framework, lo studio confronta tre importanti SWF (GPFG della Norvegia, PIF dell’Arabia Saudita e ADIA di Abu Dhabi) con tre primari fondi PE (Blackstone, Carlyle e KKR). I risultati mostrano che alcuni SWF, ad esempio quelli provenienti da Arabia Saudita, adottano una logica d’investimento più ampia, definita ecosystem architecture, che consente loro di allinearsi con le priorità di sviluppo nazionale e di influenzare i quadri normativi già esistenti per generare valore di lungo periodo. Più che plasmare le politiche, questi fondi agiscono come strumenti integrati nelle strategie statali, ampliando la propria portata economica e lo sviluppo territoriale su orizzonti di lungo periodo. Al contrario, i fondi di PE operano tipicamente come attori finanziari che si muovono all’interno di ambienti normativi già definiti, ma restando esterni a essi. Il loro approccio rimane prevalentemente guidato da logiche finanziarie, caratterizzato da obiettivi di rendimento elevato, orizzonti di uscita ben definiti e un'interazione limitata con le politiche pubbliche. Questa distinzione evidenzia come gli SWF, in alcuni casi, riescano a ottenere non solo un allineamento strategico ma anche performance finanziarie superiori rispetto ai benchmark dei PE. La tesi mette in luce come strutture di governance, contesti normativi e l’allineamento geografico influenzino in modo determinante gli esiti degli investimenti. In sistemi energetici di grandi dimensioni e progetti nazionali, gli SWF mostrano vantaggi distintivi nella gestione della complessità politico-regolatoria, confermando il loro ruolo strategico e crescente nella transizione energetica globale.As global energy markets undergo a profound transformation, the role of long-term institutional investors in shaping sustainable energy futures has become increasingly strategic. This thesis investigates how Sovereign Wealth Funds (SWFs) and Private Equity (PE) funds approach energy investments, with the aim of identifying investment rationales, structural differences, and potential best practices. To this end, it adopts a dual-framework methodology: the Nine- Dimension SWF Assessment Framework, which offers a comprehensive view of institutional structure and strategic orientation, and the IRFA Taxonomy (Investor Objective, Resource Fit, Advantage Clusters), used to classify over 1,500 energy transactions based on investment objective, resource alignment, and context-specific advantages. Applying these frameworks, the study compares three major SWFs (Norway’s GPFG, Saudi Arabia’s PIF, and Abu Dhabi’s ADIA) with three leading PE firms (Blackstone, Carlyle, and KKR). The results show that certain SWFs, for example those from Saudi Arabia, adopt a broader investment logic, termed ecosystem architecture, that enables them to align with national development priorities and influence policy frameworks to generate long-term value. Rather than shaping policies, these funds operate as instruments embedded within national strategies, amplifying their developmental reach and economic footprint over extended horizons. In contrast, PE funds typically function as agile financial actors that navigate existing policy environments but remain external to them. Their approach is predominantly financially driven, characterized by high-return targets, clear exit horizons, and limited interaction with broader policy goals. This distinction reveals how SWFs, in select cases, can achieve not only strategic alignment but also superior financial performance compared to PE benchmarks. The thesis highlights how governance structures, policy contexts, and resource endowments critically shape investment outcomes. In giga-scale energy platforms and integrated national projects, SWFs demonstrate distinct advantages in navigating political and regulatory complexity, underscoring their unique and growing role in the global energy transition

Gut microbiota-motility interregulation:Insights from in vivo, ex vivo and in silico studies

The human gastrointestinal tract is home to trillions of microbes. Gut microbial communities have a significant regulatory role in the intestinal physiology, such as gut motility. Microbial effect on gut motility is often evoked by bioactive molecules from various sources, including microbial break down of carbohydrates, fibers or proteins. In turn, gut motility regulates the colonization within the microbial ecosystem. However, the underlying mechanisms of such regulation remain obscure. Deciphering the inter-regulatory mechanisms of the microbiota and bowel function is crucial for the prevention and treatment of gut dysmotility, a comorbidity associated with many diseases. In this review, we present an overview of the current knowledge on the impact of gut microbiota and its products on bowel motility. We discuss the currently available techniques employed to assess the changes in the intestinal motility. Further, we highlight the open challenges, and incorporate biophysical elements of microbes-motility interplay, in an attempt to lay the foundation for describing long-term impacts of microbial metabolite-induced changes in gut motility

Bead-Based Hydrodynamic Simulations of Rigid Magnetic Micropropellers

The field of synthetic microswimmers, micro-robots moving in aqueous environments, has evolved significantly in the last years. Micro-robots actuated and steered by external magnetic fields are of particular interest because of the biocompatibility of this energy source and the possibility of remote control, features suited for biomedical applications. While initial work has mostly focused on helical shapes, the design space under consideration has widened considerably with recent works, opening up new possibilities for optimization of propellers to meet specific requirements. Understanding the relation between shape on the one hand and targeted actuation and steerability on the other hand requires an understanding of their propulsion behavior. Here we propose hydrodynamic simulations for the characterization of rigid micropropellers of any shape, actuated by rotating external magnetic fields. The method consists of approximating the propellers by rigid clusters of spheres. We characterize the influence of model parameters on the swimming behavior to identify optimal simulation parameters using helical propellers as a test system. We then explore the behavior of randomly shaped propellers that were recently characterized experimentally. The simulations show that the orientation of the magnetic moment with respect to the propeller's internal coordinate system has a strong impact on the propulsion behavior and has to be known with a precision of ≤ 5° to predict the propeller's velocity-frequency curve. This result emphasizes the importance of the magnetic properties of the micropropellers for the design of desired functionalities for potential biomedical applications, and in particular the importance of their orientation within the propeller's structure

Long-range conformational changes in the nucleotide-bound states of the DEAD-box helicase Vasa

DEAD-box helicases use ATP to unwind short double-stranded RNA (dsRNA). The helicase core consists of two discrete domains, termed RecA_N and RecA_C. The nucleotide binding site is harbored in RecA_N, while both RecA_N and RecA_C are involved in RNA recognition and ATP hydrolysis. In the absence of nucleotides or RNA, RecA_N and RecA_C do not interact (“open” form of the enzyme). In the presence of both RNA and ATP the two domains come together (“closed” form), building the composite RNA binding site and stimulating ATP hydrolysis. Because of the different roles and thermodynamic properties of the ADP-bound and ATP-bound states in the catalytic cycle, the conformations of DEAD-box helicases in complex with ATP and ADP are assumed to be different. However, the available crystal structures do not recapitulate these supposed differences and show identical conformations of DEAD-box helicases independent of the identity of the bound nucleotide. Here, we use NMR to demonstrate that the conformations of the ATP- and ADP-bound forms of the DEAD-box helicase Vasa are indeed different, contrary to the results from x-ray crystallography. These differences do not relate to the populations of the open and closed forms, but are intrinsic to the RecA_N domain. NMR chemical shift analysis reveals the regions of RecA_N where the average conformations of Vasa-ADP and Vasa-ATP are most different and indicates that these differences may contribute to modulating the affinity of the two nucleotide-bound complexes for RNA substrates

Simulando problemas en el ciclo lectivo 2013

Se describe una experiencia realizada en el ciclo lectivo 2013 en la asignatura Modelos y Simulación, fundamentada en el Aprendizaje Basado en Problemas y su abordaje con métodos propios de la asignatura. El designio que guía su abordaje es fomentar el pensamiento crítico, resolutivo y mejorar la construcción de conocimientos de los estudiantes enfocándose en la elaboración de posibles soluciones frente a abstracciones de problemas reales y su resolución con métodos de simulación.Palabra(s) clave(s): Modelos y Simulación, Aprendizaje Basado en Problemas, Construcción del conocimiento

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Effectiveness of therapeutic exercise in older adults with depressive symptoms, in the context of the covid-19 pandemic, in Corrientes Capital, from 2020 to 2022

Introduction: Population aging, exacerbated by the COVID-19 pandemic, has shown a significant increase in mood disorders, especially depression, in older adults. Immobility, social isolation and fear of contagion have aggravated this situation. This is where the importance of the Bachelor of Kinesiology and his humanized action towards this age group lies. Objective: To describe the effectiveness of therapeutic exercise in states of depression in older adults and Kinesic intervention in exercise planning. Methodology: A quantitative, descriptive and cross-sectional study was carried out in a sample of 70 older adults (60-99 years) with symptoms of depression, treated at the Geriatric Hospital of Corrientes between 2020 and 2022. The participants were selected by convenience and met inclusion criteria. The information was collected with a structured questionnaire of variables such as age, sex, physical exercises, depressive symptoms, activities of daily living. Results: 90% of participants reported a significant improvement in their mood and a decrease in depressive symptoms after the physical therapy intervention. In addition, an increase in muscle strength, flexibility, and aerobic capacity was observed in the participants. Conclusion: The results support the efficacy of therapeutic exercise as a non-pharmacological intervention to improve the mental and physical health of older adults with depression. However, longitudinal studies with larger samples are needed and therapeutic exercise programs should be implemented in geriatric institutions with professional training in this area.Introducción: El envejecimiento poblacional, exacerbado por la pandemia de COVID-19, ha evidenciado un aumento significativo en los trastornos del estado de ánimo, especialmente la depresión, en adultos mayores. La inmovilidad, el aislamiento social y el miedo al contagio han agravado esta situación. Es ahí la importancia del Licenciado en kinesiología y su accionar humanizado hacia este grupo etario. Objetivo: Describir la efectividad del ejercicio terapéutico en estados de depresión en adultos mayores e intervención Kinésica en la planificación de ejercicios. Metodología: Se realizó un estudio cuantitativo, descriptivo y transversal en una muestra de 70 adultos mayores (60-99 años) con síntomas de depresión, atendidos en el Hospital Geriátrico de Corrientes entre 2020 y 2022. Los participantes fueron seleccionados por conveniencia y con criterios de inclusión. La recolección de información se realizó con un cuestionario estructurado de variables como edad, sexo, ejercicios físicos, síntomas depresivos, actividades de la vida diaria. Resultados: El 90% de los participantes reportó una mejora significativa en su estado de ánimo y una disminución de los síntomas depresivos tras la intervención kinésica. Además, se observó un aumento en la fuerza muscular, la flexibilidad y la capacidad aeróbica de los participantes. Conclusión: Los resultados respaldan la eficacia del ejercicio terapéutico como una intervención no farmacológica para mejorar la salud mental y física de los adultos mayores con depresión. Sin embargo, es necesario realizar estudios longitudinales y con muestras más grandes e implementar programas de ejercicio terapéutico en instituciones geriátricas con formación profesional en esta área

High-speed motility originates from cooperatively pushing and pulling flagella bundles in bilophotrichous bacteria.

Funder: Max-Planck-Gesellschaft; FundRef: http://dx.doi.org/10.13039/501100004189Funder: IMPRS on Multiscale BiosystemsFunder: French National Research Agency; FundRef: http://dx.doi.org/10.13039/501100001665; Grant(s): ANR Tremplin-ERC: ANR-16-TERC-0025-01Bacteria propel and change direction by rotating long, helical filaments, called flagella. The number of flagella, their arrangement on the cell body and their sense of rotation hypothetically determine the locomotion characteristics of a species. The movement of the most rapid microorganisms has in particular remained unexplored because of additional experimental limitations. We show that magnetotactic cocci with two flagella bundles on one pole swim faster than 500 µm·s-1 along a double helical path, making them one of the fastest natural microswimmers. We additionally reveal that the cells reorient in less than 5 ms, an order of magnitude faster than reported so far for any other bacteria. Using hydrodynamic modeling, we demonstrate that a mode where a pushing and a pulling bundle cooperate is the only possibility to enable both helical tracks and fast reorientations. The advantage of sheathed flagella bundles is the high rigidity, making high swimming speeds possible

Elaboración de gráficas de predicción para la retención de arsénico en el suelo del la reserva ecológica los Ilinizas en la provincia de Cotopaxi durante el periodo 20-21.

The presence of arsenic in soil is a risk to ecosystems and human health, although its presence can be natural or anthropogenic, by generating a predictive model of arsenic retention in the Los Ilinizas Ecological Reserve it is possible to determine the effects on the environment. The study and sampling area is located in the Iliniza, south of the hot springs of Cunugyacu parish of San Juan of Pastocalle, county Latacunga, province of Cotopaxi. Its objective is to generate a predictive graphs for arsenic retention in the different sampling points of the Los Ilinizas Ecological Reserve study area by means of comparative graphs. Composite soil sampling was carried out in a grid every 100m, obtaining 22 samples, taking into account the presence of natural factors associated with volcanic activity in the area. Laboratory analyses were performed at the university facilities using the colorimeter test for arsenic, using a solution of 500 ug As/ L, 1 g soil sample, and different agitation periods from 30 minutes to 48 hours, in order to plot the arsenic retention behavior when acting together solution+soil. By experimentally analyzing each sample and using comparison graphs, a predictive model was generated that yields arsenic retention of 10% to 35% in less agitation time (30 minutes to 8 hours) and 42% to 53% arsenic retention in longer hours (12 to 48 hours).La presencia de arsénico en los suelos es un riesgo para ecosistemas y la salud humana, a pesar que su existencia puede ser natural o antropogénica, al generar un modelo de predicción de retención de Arsénico en la Reserva Ecológica Los Ilinizas se puede determinar los efectos al ambiente. El área de estudio y muestreo está ubicada en el Iliniza sur a la altura de las termas de Cunugyacu parroquia San Juan de Pasto calle, cantón Latacunga, provincia de Cotopaxi. Tiene como objetivo generar gráficas de predicción para retención de Arsénico en los diferentes puntos de muestreo del área de estudio de la Reserva Ecológica Los Ilinizas por medio de gráficas comparativas. Se realizó muestreo compuesto del suelo en forma de cuadricula cada 100m obteniendo 22 muestras, teniendo en cuenta presencia de factores naturales asociados con actividad volcánica de la zona. Los análisis de laboratorio se realizaron en las instalaciones de la universidad usando el test de colorímetro para arsénico, empleando una solución de 500 ug As/ L, 1 g de muestra de suelo y diferentes periodos de agitación de 30 min a 48 h, con el fin de graficar el comportamiento de retención de arsénico al actuar conjuntamente solución +suelo. Al analizar experimentalmente cada muestra y usando gráficas de comparación, se generó un modelo predictivo que arroja retención de arsénico de un 10% a 35% en menor tiempo de agitación (30min a 8 horas) y de 42% a 53% de retención de arsénico en horas mayores (12 a 48 horas