Sphingomyelins Prevent Propagation of Lipid Peroxidation—LC-MS/MS Evaluation of Inhibition Mechanisms

Free radical driven lipid peroxidation is a chain reaction which can lead to oxidative degradation of biological membranes. Propagation vs. termination rates of peroxidation in biological membranes are determined by a variety of factors including fatty acyl chain composition, presence of antioxidants, as well as biophysical properties of mono- or bilayers. Sphingomyelins (SMs), a class of sphingophospholipids, were previously described to inhibit lipid oxidation most probably via the formation of H-bond network within membranes. To address the “antioxidant” potential of SMs, we performed LC-MS/MS analysis of model SM/glycerophosphatidylcholine (PC) liposomes with different SM fraction after induction of radical driven lipid peroxidation. Increasing SM fraction led to a strong suppression of lipid peroxidation. Electrochemical oxidation of non-liposomal SMs eliminated the observed effect, indicating the importance of membrane structure for inhibition of peroxidation propagation. High resolution MS analysis of lipid peroxidation products (LPPs) observed in in vitro oxidized SM/PC liposomes allowed to identify and relatively quantify SM- and PC-derived LPPs. Moreover, mapping quantified LPPs to the known pathways of lipid peroxidation allowed to demonstrate significant decrease in mono-hydroxy(epoxy) LPPs relative to mono-keto derivatives in SM-rich liposomes. The results presented here illustrate an important property of SMs in biological membranes, acting as “biophysical antioxidant”. Furthermore, a ratio between mono-keto/mono-hydroxy(epoxy) oxidized species can be used as a marker of lipid peroxidation propagation in the presence of different antioxidants

Amor, trabajo y (des)protección social. Una aproximación al cuidado no remunerado de personas mayores en la ciudad de Mar del Plata, Argentina

En este artículo se analizan las condiciones de familiarización y feminización del cuidado de personas mayores en la ciudad de Mar del Plata, Argentina. En el país, la organización social del cuidado y las normativas que la regulan están signadas por un marcado familiarismo, lo que restringe las oportunidades de autonomía de las personas cuidadoras y limita el acceso a cuidados de calidad y bienestar material a las personas mayores. El Estado se hace presente en situaciones de extrema gravedad o ausencia de redes familiares, imponiendo la tensión entre el abandono y la resignación del proyecto de vida propio. La investigación que se recupera en este artículo se inició en un contexto anterior a la declaración de la pandemia y continuó, con adaptaciones metodológicas, en los primeros dos meses de pandemia. Recuperamos, a través de entrevistas y un cuestionario autoadministrado, la experiencia de mujeres cuidadoras no remuneradas de personas mayores, su perspectiva sobre el impacto del cuidado no remunerado en sus proyectos de vida y las representaciones subjetivas en torno a la labor que realizan.This article analyzes the conditions of familiarization and feminization of elderly care in the city of Mar del Plata, Argentina. In the country, the social organization of care and the regulations that regulate it are marked by a marked familiarity, which restricts the opportunities for autonomy of caregivers and limits access to quality care and material well-being for the elderly. The State is present in situations of extreme gravity or absence of family networks, imposing the tension between abandonment and resignation of one’s own life project. The research recovered in this article began in a context prior to the declaration of the pandemic and continued, with methodological adaptations, in the first two months of the pandemic. We recover, through interviews and a self-administered questionnaire, the experience of unpaid caregivers of the elderly, their perspective on the impact of unpaid care on their life projects and subjective representations about the work they do.Fil: Cutuli, Romina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Camou, Rosario. Universidad Nacional de Mar del Plata; Argentina.Fil: Colombo. Antonella. Universidad Nacional de Mar del Plata; Argentina.Fil: Vinitzky, Marianella. Universidad Nacional de Mar del Plata; Argentina

Analysis of the human Y-chromosome haplogroup Q characterizes ancient population movements in Eurasia and the Americas

Background: Recent genome studies of modern and ancient samples have proposed that Native Americans derive from a subset of the Eurasian gene pool carried to America by an ancestral Beringian population, from which two well-differentiated components originated and subsequently mixed in different proportion during their spread in the Americas. To assess the timing, places of origin and extent of admixture between these components, we performed an analysis of the Y-chromosome haplogroup Q, which is the only Pan-American haplogroup and accounts for virtually all Native American Y chromosomes in Mesoamerica and South America. Results: Our analyses of 1.5 Mb of 152 Y chromosomes, 34 re-sequenced in this work, support a "coastal and inland routes scenario" for the first entrance of modern humans in North America. We show a major phase of male population growth in the Americas after 15 thousand years ago (kya), followed by a period of constant population size from 8 to 3 kya, after which a secondary sign of growth was registered. The estimated dates of the first expansion in Mesoamerica and the Isthmo-Colombian Area, mainly revealed by haplogroup Q-Z780, suggest an entrance in South America prior to 15 kya. During the global constant population size phase, local South American hints of growth were registered by different Q-M848 sub-clades. These expansion events, which started during the Holocene with the improvement of climatic conditions, can be ascribed to multiple cultural changes rather than a steady population growth and a single cohesive culture diffusion as it occurred in Europe. Conclusions: We established and dated a detailed haplogroup Q phylogeny that provides new insights into the geographic distribution of its Eurasian and American branches in modern and ancient samples

Dissolution of an ensemble of differently shaped poly-dispersed drug particles undergoing solubility reduction: mathematical modelling

The aim of this theoretical paper is to develop a mathematical model for describing the dissolution process, in a finite liquid environment, of an ensemble of poly-dispersed drug particles, in form of sphere, cylinder and parallelepiped that can undergo solubility reduction due to phase transition induced by dissolution. The main result of this work consists in its simplicity as, whatever the particular particles size distribution, only two ordinary differential equations are needed to describe the dissolution process. This, in turn, reflects in a very powerful and agile theoretical tool that can be easily implemented in electronic sheets, a widespread tool among the research community. Another model advantage lies on the possibility of determining its parameters by means of common independent techniques thus enabling the evaluation of the importance of solid wettability on the dissolution process.</p

Efecto diferencial de dos cepas de Rhizophagus intraradices sobre la biomasa y el rendimiento y composición de aceites esenciales de Calamintha nepeta

El objetivo de este trabajo fue determinar, bajo condiciones de invernadero, el efecto de dos cepas geográficamente diferentes de Rhizophagus intraradices (M3 y GA5) sobre la biomasa total y el rendimiento y composición de aceites esenciales (AE) de Calamintha nepeta, con fertilización fosforada (P) o sin esta. La biomasa de la planta no fue significativamente afectada por ningún tratamiento, y se observaron valores más altos en las plantas control. Las cepas mostraron diferencias en sus tasas de colonización y en las respuestas a la fertilización con fósforo: M3 redujo sus valores de colonización, mientras que GA5 no los modificó. En ausencia de fertilización fosforada, las plantas colonizadas por ambas cepas presentaron rendimientos de AE diferentes a aquellos de las plantas control: M3 los aumentó y GA5 los disminuyó. La composición porcentual de AE no fue modificada significativamente por ninguno de los tratamientos. M3 podría ser considerada como un posible bioinoculante fúngico para la producción de C. nepeta destinada al mercado de las plantas aromáticas.The aim of this work was to determine the effects of two geographically different strains of Rhizophagus intraradices (M3 and GA5) on the total biomass and essential oil (EO) yield and composition of Calamintha nepeta, with or without phosphorus (P) fertilization, under greenhouse conditions.The plant biomass was not significantly affected by any of the treatments, showing higher values in control plants. Strains had a differential response in their root colonization rates: M3 reduced these parameters while GA5 did not modify them. Both strains affected EO yield in absence of P fertilization: M3 promoted EO yield in C. nepeta plants and GA5 resulted in negative effects. The percentage composition of EO was not significantly modified by either strain or P fertilization. M3 strain could be a potential fungal bioinoculant for production and commercialization of C. nepeta in the aromatic plant market.Fil: Colombo, Roxana. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental; ArgentinaFil: Martinez, Alicia Elba. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental; ArgentinaFil: Fernández Di Pardo, Agustina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental; ArgentinaFil: Fernandez Bidondo, Laura. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental; ArgentinaFil: Van Baren, Catalina Maria. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Química y Metabolismo del Fármaco; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco (i); ArgentinaFil: Di Leo Lira, Paola Maria del Rosario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Química y Metabolismo del Fármaco; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco (i); ArgentinaFil: Godeas, Alicia Margarita. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental; Argentin

Heatwave breaks down the linearity between sun-induced fluorescence and gross primary production

Sun-induced fluorescence in the far-red region (SIF) is increasingly used as a remote and proximal-sensing tool capable of tracking vegetation gross primary production (GPP). However, the use of SIF to probe changes in GPP is challenged during extreme climatic events, such as heatwaves. Here, we examined how the 2018 European heatwave (HW) affected the GPP-SIF relationship in evergreen broadleaved trees with a relatively invariant canopy structure. To do so, we combined canopy-scale SIF measurements, GPP estimated from an eddy covariance tower, and active pulse amplitude modulation fluorescence. The HW caused an inversion of the photosynthesis-fluorescence relationship at both the canopy and leaf scales. The highly nonlinear relationship was strongly shaped by nonphotochemical quenching (NPQ), that is, a dissipation mechanism to protect from the adverse effects of high light intensity. During the extreme heat stress, plants experienced a saturation of NPQ, causing a change in the allocation of energy dissipation pathways towards SIF. Our results show the complex modulation of the NPQ-SIF-GPP relationship at an extreme level of heat stress, which is not completely represented in state-of-the-art coupled radiative transfer and photosynthesis models.Peer reviewe

BIOCHEMICAL AND FUNCTIONAL CHARACTERIZATION OF THE BACTERIAL PsaR1 SENSOR IN THE PSEUDOMONAS SYRINGAE PV. ACTINIDIAE-KIWIFRUIT INTERACTION

Kiwifruit bacterial canker, caused by Pseudomonas syringae pv. actinidiae (Psa), is responsible for important economic losses in all major areas of kiwifruit production worldwide, including Italy. As for many other bacterial diseases, current plant defense strategies against Psa are mainly based on the use of copper-containing products, which raise eco-toxicological problems. Revision and restriction processes regarding the use of high amounts of copper in agriculture impose an urgent study of new solutions, efficient and eco-compatible, avoiding at the same time the occurrence of new resistance to active molecules. Innovative strategies are based for instance on the application of targeted treatments for \u201cweakening\u201d the pathogen, i.e. to reduce its virulence within its host. However, this requires improving our knowledge regarding molecular mechanisms controlling bacterial virulence induction. A key regulator of bacterial virulence is the so-called \u2018quorum-sensing\u2019 (QS), that links bacterial density to gene expression. This mechanism allows bacteria to communicate within the bacterial community and with their environment, via small diffusible molecules. The prototypical QS system of Gram-negative bacteria consists of a LuxI-type synthase that produces the signal molecules acyl homoserine lactones (AHLs) and a cognate LuxR-type receptor/regulator that senses signal specific threshold concentration. An interesting subgroup of LuxR receptors lacks a genetically linked LuxI and has been termed \u201csolos\u201d. These \u201csolos\u201d are assumed to sense AHLs from neighboring bacteria, bacterial molecules other than AHLs or still unknown plant-produced compounds in the case of phytopathogenic bacteria. Interestingly, Psa does not produce AHLs but possesses three LuxR solos, which likely contribute to Psa virulence. As a first candidate for a targeted inhibition strategy against Psa, we are currently investigating the biochemical properties of the sensor PsaR1. To that purpose, several tentative have been made to obtain the soluble recombinant sensor in a heterologous system. Once achieved, we demonstrated that it does not bind AHLs, thus excluding the possibility to sense AHLs from neighboring bacteria, and we are currently setting a chemical screening, based on thermal shift assay, to identify the class(es) of molecules able to bind to the sensor. On the other hand, we aim to identify the pathway(s) regulated by PsaR1 during Psa interaction with kiwifruit, during different phases of the infection. Thus, a microarray analysis is being performed to compare the transcriptomic profiles of wild-type and psaR1 knockout Psa strains at both exponential and stationary growth phase, in conditions mimicking the interaction with the host plant, i.e. minimal medium supplemented with kiwifruit extract

Reduced engagement with social stimuli in 6-month-old infants with later Autism Spectrum Disorder: a longitudinal prospective study of infants at high familial risk

Background: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that affects more than 1% of the population, and close to 20% of prospectively studied infants with an older sibling with ASD. Although significant progress has been made in characterizing the emergence of behavioral symptoms of ASD, far less is known about the underlying disruptions to early learning. Recent models suggest that core aspects of the causal path to ASD may only be apparent in early infancy. Here, we investigated social attention in 6- and 12-month-old infants who did and did not meet criteria for ASD at 24 months using both cognitive and electrophysiological methods. We hypothesized that a reduction in attention engagement to faces would be associated with later ASD. Methods: In a prospective longitudinal design, we used measures of both visual attention (habituation) and brain function (event-related potentials to faces and objects) at 6 and 12 months, and investigated the relationship to ASD outcome at 24 months. Results: High-risk infants who met criteria for ASD at 24 months showed shorter epochs of visual attention, faster but less prolonged neural activation to faces, and delayed sensitization responses (increases in looking) to faces at 6 months; these differences were less apparent at 12 months. These findings are consistent with disrupted engagement of sustained attention to social stimuli. Conclusions: These findings suggest that there may be fundamental early disruptions to attention engagement that may have cascading consequences for later social functioning

Hypoxia Promotes Danger-mediated Inflammation via Receptor for Advanced Glycation End Products in Cystic Fibrosis

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