Determination of the ocean tide model from LEO satellite orbital perturbation analysis

The present study concerns the determination of ocean tide model parameters from GOCE orbital perturbation analysis. The GOCE satellite was launched by the European Space Agency in 2009 and is flying on a Sun-synchronous near circular orbit, at the very low altitude of about 250 km which makes it very sensitive to tidally induced orbit perturbations. The strategy adopted for analyzing GOCE GPS tracking data is the direct fully-dynamic approach, consisting in the GOCE precise orbit determination (POD) and accumulation of the normal equations for each orbital arc, followed by a multiarc solution for the estimation of the global ocean tide parameters. The GOCE GPS observations are processed using the NAPEOS S/W system (ESA/ESOC), specific for satellite orbit determination and prediction, upgraded to inclusion of the partial derivatives with respect to the ocean tide parameters and the ocean tide model inversion capability. A sensitivity study of the ocean tide perturbations on GOCE orbit was carried out using as a reference the FES2004 model, in order to define the set of tidal harmonic parameters affecting GOCE orbit. In particular, the secular rates of the GOCE angular elements are estimated through a linear least-square fit. From GOCE mean orbital characteristics, the spectral analysis of ocean tide perturbations in the radial, transverse and normal direction is performed using Kaula's linear satellite theory. Then, the perturbation statistics by coefficient is computed, obtaining a maximum RMS of about 1.323 m for the radial component, 363.136 m for the transverse component and 76.241 m for the normal component. The temporal aliasing problem is also accounted for the recovery of tidal parameters with GOCE and the principal alias periods are calculated for each tidal perturbation frequency, considering the length of the available GOCE data record. To fix a limit for the number of parameters to be estimated, three different cutoffs are applied to the RMS perturbation coefficients, respectively equal to 5 mm for the radial component, 2 cm for the transverse component and 1 cm for the normal component, both in the prograde and retrograde case. The total parameters to be estimated result to be 490. GOCE data are processed to perform the fully-dynamic POD over daily orbital arcs from the 1st November 2009 until the 31st May 2011, but only arcs with a post-fit RMS of the GPS phase observations residuals lower than 8 mm are considered for the multiarc processing, for a total of 431 days. The obtained preliminary results show the relative error of the estimated parameters with respect to the corresponding FES2004 parameters lower than 1 for about the 16\% of the total, meaning that they are of the order of magnitude of the FES2004 parameters. GOCE orbital data were reprocessed along the same period of the previous run, initializing the ocean tide model with the estimated parameters, if present, and maintaining otherwise the FES2004 parameters. The post-fit RMS of the GPS phase residuals obtained with the new ocean tide model has a mean value of 6.5 mm, and it is noteworthy that the difference between the post-fit RMS obtained with the FES2004 model and that resulting from the new ocean tide model indicates a mean improvement of about 0.6 mm in for the 96\% of the analyzed arcs and greater than 1 mm for the 16\%, few days reach a difference of 2 mm. Finally, the orbits obtained with the estimated parameters are compared with the orbits obtained employing the FES2004 model and the official GOCE Reduced-Dynamic PSO. The 3D RMS of the difference between the orbits computed using FES2004 and those recomputed with the new parameters shows a mean value of 2.5 cm, while the 3D RMS of the difference with respect to the official R/D PSO has a mean value of 4.9 cm. Moreover, the difference between the 3D RMS of the orbit residuals between the R/D PSO and the GOCE POD with FES2004 and the RMS of the difference between the GOCE R/D PSO and the GOCE POD with the new parameters results to have a mean improvement of 0.9 cm. Further POD-Multiarc runs are certainly necessary, together with the refinement of the list of parameters to be estimated, removing excessively ill-estimated ocean tide parameters and introducing new parameters where appropriate. Indeed, the model parameter tuning and investigation is essential to adjust the best combination of parameters to be estimated. Moreover, an extension of the data set to much longer time-period should allow a substantial improvement of the obtained results. The task has proven very intensive and challenging, but the partial results obtained are encouraging and a motivation for future analysis

Aproximaciones a una Pathosformel del Destierro

Este trabajo se propone el análisis de un fenómeno caro a la cultura occidental, como es la experiencia del destierro y su incidencia en el devenir de las representaciones, a partir del pensamiento del historiador alemán Aby Warburg. Desde algunas categorías warburguianas, principalmente la Pathosformel, se aborda una serie de imágenes haciendo foco en las artes visuales y la fotografía como campos de exploración y estudio. Siguiendo el paradigma indiciario de Carlo Ginzburg, se partió de una indagación en la propia memoria corporal como posible vía de acceso al reconocimiento de gestos vinculados al destierro en representaciones de distintas épocas, tomando en cuenta que la experiencia individual se encuentra inscripta y en íntima relación con una más amplia, colectiva. Es desde la memoria cultural que puede pensarse el tema en términos de Pathosformel en la imagen.En este artículo se ha puesto el acento en la fundamentación teórica de tal exploración, quedando para otra instancia la profundización de los aspectos estrictamente visuales. Approaches to a Pathosformel of UprootednessAbstractThis work proposes the analysis of the experience of uprootedness, a phenomenon of utmost importance to western culture, and its impact on the development of representations, based on the thought of German historianAby Warburg. From some Warburgian categories, principally Pathosformel, a series of images is addressed focusing on the visual arts and photography as fields of exploration and study. Following Carlo Ginzburg's indexical paradigm, the starting point was an inquiry into one’s own body memory as a possible way to recognize gestures linked to uprootedness in representations from different eras, taking into account that the individual experience isinscribed and in close relationship with a broader collective one. It is from the cultural memory that this theme can be thought of in terms of Pathosformel in the image. In this article, the emphasis has been placed on the theoretical foundation of such exploration, leaving aside for the moment a deeper probing of the strictly visual aspects.Keywords: Pathosformel; uprootedness; representation; gesture; body

Caracterización del fenómeno de persistencia en el patógeno humano Chlamydia trachomatis

Tesis (Doctora en Ciencias Químicas) - - Universidad Nacional de Córdoba. Facultad de Ciencias Químicas, 2019Chlamydia trachomatis es el patógeno bacteriano de transmisión sexual más común en humanos y una causa frecuente de infecciones asintomáticas y persistentes que conducen a complicaciones graves, particularmente en mujeres jóvenes. Chlamydia presenta un estilo de vida intracelular obligado único que involucra la transición cíclica entre su forma de desarrollo infectiva o cuerpo elemental y su forma replicativa o cuerpo reticular dentro de una vacuola denominada “inclusión”. En presencia de factores estresantes como el interferón gamma (IFNγ) o los antibióticos beta-lactámicos, C. trachomatis sufre una interrupción en su ciclo replicativo y entra en un estado viable pero no cultivable, “persistente”, también llamado persistencia clamidial, generalmente asociado a la presencia de cuerpos reticulares aberrantes y de mayor tamaño. Al removerse los factores de estrés, estas bacterias reanudan la división celular y las transiciones entre sus formas de desarrollo. Por lo tanto, la persistencia clamidial se considera un factor clave en la capacidad de estas bacterias para evadir diferentes efectos antimicrobianos. En esta tesis, se describe un screening genético para identificar y caracterizar mutantes de C. trachomatis con defectos en la recuperación post-estrés inducido por IFNγ y/o penicilina. Utilizando una colección de aproximadamente 1000 mutantes químicas completamente secuenciadas de C. trachomatis LGV-L2, se encontró que la mutante M275 es defectuosa en la recuperación de estrés inducido por IFNγ pero no por penicilina. Mediante la transferencia lateral de genes y análisis de recombinantes se identificó ptr, que codifica una posible proteasa, como un gen probablemente requerido para la recuperación del estrés inducido por IFNγ. Para confirmar estos resultados se construyó una cepa nula para ptr (L2 ptr::GII), la cual también mostró defectos en la recuperación del estrés inducido por IFNγ, y este defecto se restableció mediante la complementación de la expresión de Ptr. L2 ptr::GII, al igual que M275, mostró una menor tasa de diferenciación de RB a EB y una replicación del genoma reducida durante la recuperación después del tratamiento con IFNγ, lo que indica que Ptr es necesaria para una salida rápida del estrés inducido por IFNγ. Asimismo, se desarrollaron anticuerpos contra Ptr que nos permitieron observar que esta proteína es secretada al lumen de la inclusión clamidial. Utilizando un modelo murino de infección vaginal se observó un clearance disminuido a los 14 días post-infección para L2 ptr::GII, sugiriendo que la anulación de ptr causa una demora en la eliminación de C. trachomatis en el tracto genital femenino durante la infección in vivo. Por otro lado, se caracterizó la mutante M111, que presentó defectos en la recuperación luego del estrés inducido por IFNγ o por penicilina. Dicha mutante porta una única mutación sin sentido en pmpC, además de mutaciones con cambio de sentido en 5 genes adicionales. El gen pmpC codifica para una proteína polimórfica de membrana perteneciente a una familia de proteínas exclusiva de Chlamydia. Mediante la inactivación sitio-dirigida de genes por inserción se identificó pmpC como un gen necesario para la recuperación del estrés inducido por IFNγ o penicilina. Adicionalmente, se observó que la anulación de pmpC causa un defecto en la adherencia e invasión en las células hospedadoras, e induce la formación de agregados bacterianos dentro de la inclusión clamidial. En conclusión, este trabajo de tesis identificó a ptr y pmpC como genes involucrados en la persistencia clamidial.2021-12-3

Ptr/CTL0175 is required for the efficient recovery of chlamydia trachomatisfrom stress induced by gamma-interferon

Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in humans and a frequent cause of asymptomatic, persistent infections leading to serious complications, particularly in young women. Chlamydia displays a unique obligate intracellular lifestyle involving the infectious elementary body and the replicative reticulate body. In the presence of stressors such as gamma-interferon (IFNγ) or beta-lactam antibiotics, C. trachomatis undergoes an interruption in its replication cycle and enters a viable but non-cultivable state. Upon removal of the stressors, surviving C. trachomatis resume cell division and developmental transitions. In this report, we describe a genetic screen to identify C. trachomatis mutants with defects in recovery from IFNγ- and/or penicillin-induced stress and characterized a chemically derived C. trachomatis mutant strain that exhibited a significant decrease in recovery from IFNγ- but not penicillin-induced stress. Through lateral gene transfer and targeted insertional gene inactivation we identified ptr, encoding a predicted protease, as a gene required for recovery from IFNγ-induced stress. A C. trachomatis LGV-L2 ptr-null strain displayed reduced generation of infectious progeny and impaired genome replication upon removal of IFNγ. This defect was restored by introducing a wild type copy of ptr on a plasmid, indicating that Ptr is required for a rapid growth upon removal of IFN?. Ptr was expressed throughout the developmental cycle and localized to the inclusion lumen. Overall, our findings indicate that the putative secreted protease Ptr is required for C. trachomatis to specifically recover from IFNγ- but not penicillin-induced stress.Fil: Panzetta, Maria Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Lujan, Agustin Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Bastidas, Robert J.. University of Duke; Estados UnidosFil: Damiani, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Valdivia, Raphael H.. University of Duke; Estados UnidosFil: Saka, Hector Alex. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin

Chlorpyrifos induces endoplasmic reticulum stress in JEG-3 cells

Chlorpyrifos (CPF) is an organophosphorous pesticide widely used in agricultural, industrial, and household applications. We have previously shown that JEG-3 cells are able to attenuate the oxidative stress induced by CPF through the adaptive activation of the Nrf2/ARE pathway. Considering that there is a relationship between oxidative stress and endoplasmic reticulum stress (ER), herein we investigated whether CPF also induces ER stress in JEG-3 cells. Cells were exposed to 50 μM or 100 μM CPF during 24 h in conditions where cell viability was not altered. Western blot and PCR assays were used to explore the protein and mRNA levels of ER stress biomarkers, respectively. CPF induced an increase of the typical ER stress-related proteins, such as GRP78/BiP and IRE1α, a sensor for the unfolded protein response, as well as in phospho-eIF2α and XBP1 mRNA splicing. Additionally, CPF led to a decrease in p53 protein expression. The downregulation of p53 levels induced by CPF was partially blocked when cells were exposed to CPF in the presence of the proteasome inhibitor MG132. Altogether, these findings point out that CPF induces ER stress in JEG-3 cells; however these cells are able to attenuate it downregulating the levels of the pro-apoptotic protein p53.Fil: Reyna, Luciana. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Flores Martín, Jésica Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Ridano, Magali Evelin. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Genti de Raimondi, Susana. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin

Chlamydia Persistence: A Survival Strategy to Evade Antimicrobial Effects in-vitro and in-vivo

The Chlamydiaceae comprise a group of highly adapted bacterial pathogens sharing a unique intracellular lifestyle. Three Chlamydia species are pathogenic to humans: Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci. C. trachomatis is the leading bacterial cause of sexually-transmitted infections and infectious blindness worldwide. Chlamydia pneumoniae is a major cause of community-acquired atypical pneumonia. C. psittaci primarily affects psittacine birds and can be transmitted to humans causing psittacosis, a potentially fatal form of pneumonia. As opposed to other bacterial pathogens, the spread of clinically relevant antimicrobial resistance genes does not seem to be a major problem for the treatment of Chlamydia infections. However, when exposed to stressing conditions, like those arising from exposure to antimicrobial stimuli, these bacteria undergo a temporary interruption in their replication cycle and enter a viable but non-cultivable state known as persistence. When the stressing conditions are removed, Chlamydia resumes replication and generation of infectious particles. This review gives an overview of the different survival strategies used by Chlamydia to evade the deleterious effects of penicillin and IFNγ, with a focus on the different models used to study Chlamydia persistence, their contribution to elucidating the molecular basis of this complex phenomenon and their potential implications for studies in animal models of infection

Impact of ionizing radiation on cell-ECM mechanical crosstalk in breast cancer

The stiffness of the extracellular matrix plays a crucial role in cell motility and spreading, influencing cell morphology through cytoskeleton organization and transmembrane proteins’ expression. In this context, mechanical characterization of both cells and the extracellular matrix gains prominence for enhanced diagnostics and clinical decision-making. Here, we investigate the combined effect of mechanotransduction and ionizing radiations on altering cells’ mechanical properties, analysing mammary cell lines (MCF10A and MDA-MB-231) after X-ray radiotherapy (2 and 10 Gy). We found that ionizing radiations sensitively affect adenocarcinoma cells cultured on substrates mimicking cancerous tissue stiffness (15 kPa), inducing an increased structuration of paxillin-rich focal adhesions and cytoskeleton: this process translates in the augmentation of tension at the actin filaments level, causing cellular stiffness and consequently affecting cytoplasmatic/nuclear morphologies. Deeper exploration of the intricate interplay between mechanical factors and radiation should provide novel strategies to orient clinical outcomes

The lipid transfer protein StarD7: structure, function, and regulation

The steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) domain proteins constitute a family of evolutionarily conserved and widely expressed proteins that have been implicated in lipid transport, metabolism, and signaling. The 15 well-characterized mammalian START domain-containing proteins are grouped into six subfamilies. The START domain containing 7 mRNA encodes StarD7, a member of the StarD2/phosphatidylcholine transfer protein (PCTP) subfamily, which was first identified as a gene overexpressed in a choriocarcinoma cell line. Recent studies show that the StarD7 protein facilitates the delivery of phosphatidylcholine to the mitochondria. This review summarizes the latest advances in StarD7 research, focusing on the structural and biochemical features, protein-lipid interactions, and mechanisms that regulate StarD7 expression. The implications of the role of StarD7 in cell proliferation, migration, and differentiation are also discussed.Fil: Flores Martín, Jésica Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Bioquímica Clínica E Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Rena, Viviana Celeste del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Bioquímica Clínica E Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Angeletti, Sofia Claudia. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Bioquímica Clínica E Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Bioquímica Clínica E Inmunología; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Bioquímica Clínica; Argentin