National University of Quilmes

Recent developments have broadened our perception of SARS-CoV-2, indicating its capability to affect the body systemically beyond its initial recognition as a mere respiratory pathogen. However, the pathways of its widespread are not well understood. Employing a dual-modality approach, we integrated findings from a Murine Hepatitis Virus (MHV) infection model with corroborative clinical data to investigate the pervasive reach of Coronaviruses. The novel presence of viral particles within red blood cells (RBCs) was demonstrated via high-resolution transmission electron microscopy, with computational modeling elucidating a potential heme-mediated viral entry mechanism via Spike protein affinity. Our data affirm viral localization in RBCs, suggesting heme moieties as facilitators for cellular invasion. Exacerbation of MHV pathology upon hemin administration, contrasted with chloroquine-mediated amelioration, underscoring a heme-centric pathway in disease progression. These observations extend the paradigm of Coronavirus pathogenicity to include hemoprotein interactions. This study casts new light on the systemic invasion capabilities of Coronaviruses, linking RBC hemoproteins with viral virulence. The modulation of disease severity through heme-interacting agents heralds a promising avenue for COVID-19 therapeutics. Our findings propose a paradigm shift in the treatment approach, leveraging the virus-heme interplay as a strategic hinge for intervention.

In recent times, the exponential growth of sequenced genomes and structural knowledge of proteins, as well as the development of computational tools and controlled vocabularies to deal with this growth, has fueled a demand for conceptual clarification regarding the concept of function in molecular biology. In this article, we will attempt to develop an account of function fit to deal with the conceptual/philosophical problems in that domain, but which can be extended to other areas of biology. To provide this account, we will argue for three theses: (1) some authors have confused metatheoretical issues (about the meaning and application criteria of terms) with metaphysical ones (about teleology); this led them to (2) look for explicit definitions of “function”, in terms of necessary and sufficient criteria of application, in order to make the concept of function eliminable; however, (3) if one leaves metaphysical worries aside and focuses on functional attribution practices, it is more adequate to say that the concept of function has an open texture. That is, that a multiplicity of application criteria is available, none of which is sufficient nor necessary to attribute a function to a trait, and which only in concert form a clear picture. We distinguish this thesis from some usual forms of pluralism. Finally, we will illustrate this account with a historical reconstruction of the ascription of a water transport function to aquaporins.

Fluidized bed drying is a cost-effective and versatile technique for the conservation of microorganisms guaranteeing them a long useful life in terms of culture stability (viability and activity). In this work, a method for dehydration of yeasts and lactic acid bacteria using fluidized bed technology and manioc starch as carrier is described. Under assay conditions, total drying of cultures (corresponding to a decrease in aw from approximately 0.99 to 0.17) occurred with high cell survival evidencing the method efficiency for preservation of microbial cultures.

Many different oral delivery systems have been developed to protect food ingredients from degradation occurring in the harsh environmental conditions of the gastrointestinal tract, and liposomes are among the safest ones. However, because of their intrinsic tendency to aggregate and/or fuse, some strategies should be used to improve their features. In this sense, bacterial S-layer proteins (SLPs) have been used to stabilize liposomes due to their ability to reassemble as a rigid nanostructured lattice covering different surfaces. In this chapter, we will describe the experimental protocols to prepare and characterize SLP-coated multilamellar lipid vesicles which can be applied to the encapsulation of food ingredients.

In Pseudomonas donghuensis SVBP6, isolated from an agricultural field, the well‐conserved Gac‐Rsm pathway upregulates biosynthesis of the antifungal compound 7‐hydroxytropolone (7‐HT). However, 7‐HT does not fully explain the strain's Gac‐Rsm‐dependent antimicrobial activity. Here, we combined comparative transcriptomic, proteomic, and metabolomic approaches to identify novel GacS‐dependent biosynthetic gene clusters (BGC) and/or extracellular specialized metabolites. Our data revealed a broad impact of GacS on gene expression and extracellular metabolite profile of SVBP6. At both the mRNA and polypeptide levels, specialized metabolism was the main affected functional category in the gacS mutant. The major extracellular MS/MS spectral families promoted by GacS were fatty acid amides, fatty acids, and alkaloids. GacS was required for the production of the antimicrobial compound pseudoiodinine and to activate expression of the corresponding BGC. We also detected GacS‐dependent production of 2,3,4‐trihydro‐β‐carboline‐1‐one, which may add to the antimicrobial arsenal of SVBP6. Furthermore, transcriptomics and proteomics pinpointed several GacS‐activated BGCs that had escaped in silico genome mining tools. Altogether, comparative multi‐omics analyses of gacS loss‐of‐function mutants in Pseudomonas isolates are a promising strategy to uncover bioactive metabolites and/or their BGCs. Discovery of novel natural products is important for harnessing the potential of microbiota to improve crop plant growth and health.

Nowadays, incorporating quaternary ammonium groups into polymers is one of the most promising strategies for preparing antimicrobial biomaterials for general applications. The main objective of this work was to evaluate the effect of different concentrations of antimicrobial quaternary polymers in gelatin- and starch-based films for the development of active materials intended for applications in food packaging and medical fields. Two antimicrobial biobased polymers, called MeFPIAx (MeFPIA1 and MeFPIA2), were previously synthesized through the radical polymerization of itaconic acid (IA), followed by their subsequent functionalization and modification. Both polymers were incorporated into a new blend of gelatin and starch (15% w/w, 4:1 mass ratio), using glycerol (30% w/w) as a plasticizer. Films were prepared using the casting technique from aqueous dispersions of the polymers and their structure was characterized by Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR). The findings of this study showed the addition of MeFPIAx had a significant effect (p < 0.05), resulting in films with higher tensile strength (TS) and a higher Young’s modulus (YM), with values close to 20 MPa and exceeding 250 MPa, respectively. On the other hand, elongation at break (EB) values lower than 80% were obtained. Additionally, the swelling was reduced from ~400% to 100% and a reduction in water vapor permeability (Pw) was observed, thanks to the increased interaction between the polymeric chains. Differential scanning calorimetry (DSC) scans showed that the addition of MeFPIAx increased the glass transition temperatures (Tg) from 29 °C to 65 °C. Furthermore, thermogravimetry analysis (TGA) indicated an increase in the initial degradation temperatures, suggesting that the films were more thermally resistant. Finally, the films exhibited slight antioxidant activity but significant antimicrobial activity, achieving bacterial reduction values greater than 70% with the incorporation of MeFPIAx polymers against Gram-positive Staphylococcus aureus.

Sensorimotor synchronization (SMS) is the mainly specifically human ability to move in sync with a periodic external stimulus, as in keeping pace with music. The most common experimental paradigm to study its largely unknown underlying mechanism is the paced finger-tapping task, where a participant taps to a periodic sequence of brief stimuli. Contrary to reaction time, this task involves temporal prediction because the participant needs to trigger the motor action in advance for the tap and the stimulus to occur simultaneously, then an error-correction mechanism takes past performance as input to adjust the following prediction. In a different, simpler task, it has been shown that exposure to a distribution of individual temporal intervals creates a “temporal context” that can bias the estimation/production of a single target interval. As temporal estimation and production are also involved in SMS, we asked whether a paced finger-tapping task with period perturbations would show any time-related context effect. In this work we show that a perturbation context can indeed be generated by exposure to period perturbations during paced finger tapping, affecting the shape and size of the resynchronization curve. Response asymmetry is also affected, thus evidencing an interplay between context and intrinsic nonlinearities of the correction mechanism. We conclude that perturbation context calibrates the underlying error-correction mechanism in SMS.

The aim of this paper is twofold. First, we argue that killing a Conditional Threat usually involves an unnecessary act of self-defense, so killing this aggressor is usually morally impermissible. We defend this thesis by showing that this case is fundamentally similar to a case involving an Unconditional Threat in which the victim can flee to safety although this involves incurring a minor cost. Second, we analyze the thresholds of maximal harm that victims are required to bear before they are permitted to defend themselves by harming their aggressors related to the conditions of necessity and of proportionality. We argue that the maximal harm a victim is required to bear sanctioned by the condition of necessity is, all else being equal, lower than the maximal harm that a victim must bear sanctioned by the condition of proportionality. This result is relevant for determining in which cases victims may use lethal force against Conditional Threats, both in the individual case and also in the case of war.

Microbial exopolymers are gaining attention as sources for the development of biodegradable materials. Milk kefir, a fermented dairy product produced by a symbiotic community of microorganisms, generates milk kefir grains as a by-product, consisting of the polysaccharide kefiran and proteins. This study develops two materials, one from whole milk kefir grains and another from purified kefiran. Film-forming dispersions were subjected to ultrasonic homogenisation and thermal treatment, yielding homogeneous dispersions. Kefiran dispersion exhibited lower pseudoplastic behaviour and higher viscous consistency, with minimal effects from glycerol. Both films exhibited continuous and homogeneous microstructures, with kefiran films being transparent and milk kefir films displaying a yellowish tint. Analysis revealed that milk kefir films comprised approximately 30% proteins and 70% kefiran. Kefiran films demonstrated stronger interpolymeric interactions, as evidenced using thermogravimetric and mechanical tests. Glycerol increased hydration while decreasing thermal stability, glass transition temperature, elastic modulus, and tensile strength in both films. However, in kefiran films, elongation at the break and water vapour permeability decreased at low glycerol content, followed by an increase at higher plasticiser contents. This suggests an unusual interaction between glycerol and kefiran in the absence of proteins. These findings underscore differences between materials derived from the whole by-product and purified kefiran, offering insights into their potential applications.

This chapter analyzes the role of political and affective polarization in our interactions on social media. I am interested in understanding, on the one hand, how our mood and preconceptions influence the interpretation of messages on social media, and on the other hand, how the presentation of messages encourages our anger or motivates our joy. For this study, I rely on a series of survey experiments conducted in Argentina at various times from the beginning of the pandemic to the present. As these cases show, the affective reaction of social media users to messages is no different when they see verified information compared to when they share false content.

Alpha‐solenoids are a significant and diverse subset of structured tandem repeat proteins (STRPs) that are important in various domains of life. This review examines their structural and functional diversity and highlights their role in critical cellular processes such as signaling, apoptosis, and transcriptional regulation. Alpha‐solenoids can be classified into three geometric folds: low curvature, high curvature, and corkscrew, as well as eight subfolds: ankyrin repeats; Huntingtin, elongation factor 3, protein phosphatase 2A, and target of rapamycin; armadillo repeats; tetratricopeptide repeats; pentatricopeptide repeats; Pumilio repeats; transcription activator‐like; and Sel‐1 and Sel‐1‐like repeats. These subfolds represent distinct protein families with unique structural properties and functions, highlighting the versatility of alpha‐solenoids. The review also discusses their association with disease, highlighting their potential as therapeutic targets and their role in protein design. Advances in state‐of‐the‐art structure prediction methods provide new opportunities and challenges in the functional characterization and classification of this kind of fold, emphasizing the need for continued development of methods for their identification and proper data curation and deposition in the main databases.

Yerba mate infusion wastes (Ilex paraguariensis) were used to prepare an aqueous extract to develop active and intelligent films using water kefir grains as a polymeric matrix. The yerba mate extract (YM) demonstrated notable antioxidant activity attributed to its total phenolic content (245 ± 13 mg GAE/g) and exhibited colour variations at different pH values. The addition of 5% YM reinforced the matrix, increasing the mechanical strength (TS: 5.8 ± 0.7 to 7.4 ± 0.4 MPa) and increasing the initial degradation temperature (T0: 166 to 180 °C). The incorporation of 20% YM additionally produced a plasticising effect in the matrix that masked the reinforcement observed at low concentrations of YM. Films with YM had remarkable antioxidant activity, with a maximal radical scavenging activity (%RSA) of 98 ± 2 and 71 ± 2 measured by ABTS and DPPH assays, respectively. According to the migration test conducted in fatty food simulants, the quantity of migrated phenols depended on the original percentage of YM in the films. As a result of exposure to ammonia vapours, a pronounced colour change was observed on the films, indicating that the kefir films with YM could be used as a freshness indicator for food products.

Recent advances in wave energy exploitation highlight the potential of Wave Energy Converters (WECs) to significantly contribute to global clean energy demands. Numerous concepts for ocean wave energy harvesting have been developed, with specific attention to Internal Reaction Mass (IRM) systems, which are able to enclose the mechanical and electrical conversion stage within the floating hull itself, substantially reducing mantainance costs. Recent studies propose optimising the performance of IRM systems by adjusting the behaviour of the internal mass via optimal control procedures, significantly improving mechanical power available at the Power TakeOff (PTO). However, these studies often overlook energy losses associated with altering the internal mass dynamics itself, rendering any performance enhancement conclusions potentially overoptimistic. This paper addresses this gap by proposing a modified control objective that penalises these losses, offering a balanced approach to optimising the overall performance IRM WEC systems. The resulting optimal control problem is transcribed in a direct fashion, using moment-based theory, resulting in a finite-dimensional tractable nonlinear program, with application to a gyropendulum-based WEC. We show that the modified control objective is effectively able to trade-off the energy available at the PTO with the corresponding gyropendulum losses.

Upon visually detecting a moving predator animals often freeze, i.e. stop moving, to minimize being uncovered and to gather detailed information of the object's movements and properties. In certain conditions the freezing behavior can be enough to avoid a predatory menace but, when the risk is high or increases to a higher level, animals switch strategy and engage in an escape response. The neural bases underlying escape responses to visual stimuli are extensively investigated both in vertebrates and arthropods. However, those involved in freezing behaviors are much less studied. Here, we investigated the freezing behavior displayed by the crab Neohelice granulata when confronted with a variety of looming stimuli simulating objects of distinct sizes approaching on a collision course at different speeds. The experiments were performed in a treadmill-like device. Animals engaged in exploratory walks respond to the looming stimulus with freezing followed by escaping. The analysis of the stimulus optical variables shows that regardless of the looming dynamic, the freezing decision is made when the angular size of the object increases by 1.4°. In vivo intracellular recording responses of Monostratified Lobula Giant Neurons (MLG1) to the same looming stimuli show that the freezing times correlate with the times predicted by a hypothetical spike counter of this neuron.

En esta reseña se analiza el libro escrito por Paulo Drinot, titulado: "Mariátegui o el cojito genial. Historia y discapacidad en el Perú" y publicado por la Editorial Planeta en el 2023. José Carlos Mariátegui, nacido en 1894 y fallecido en 1930, devendría un protagonista central del pensamiento nacional y popular latinoamericano al ser considerado el primer marxista de la región. La envergadura de su rol, lo ha convertido en extenso objeto de estudio historiográfico. No obstante, a través del libro José Carlos Mariátegui o el "cojito genial", Paulo Drinot analiza la figura de Mariátegui focalizando en un aspecto pasado hasta ahora pasado por alto desde el estado de la cuestión: su discapacidad. En la reseña se realiza un balance crítico del aporte de esta obra al campo de los estudios críticos latinoamericanos en discapacidad