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Bacterial Type III Secretion Systems (T3SSs) are specialized multicomponent nanomachines that mediate the transport of proteins either to extracellular locations or deliver Type III Secretion effectors directly into eukaryotic host cell cytoplasm. Shigella, the causing agent of bacillary dysentery or shigellosis, bears a set of T3SS proteins termed translocators that form a pore in the host cell membrane. IpaB, the major translocator of the system, is a key factor in promoting Shigella pathogenicity. Prior to secretion, IpaB is maintained inside the bacterial cytoplasm in a secretion competent folding state thanks to its cognate chaperone IpgC. IpgC couples T3SS activation to transcription of effector genes through its binding to MxiE, probably after the delivery of IpaB to the secretion export gate. Small Angle X-ray Scattering experiments and modeling reveal that IpgC is found in different oligomeric states in solution, as it forms a stable heterodimer with full-length IpaB in contrast to an aggregation-prone homodimer in the absence of the translocator. These results support a stoichiometry of interaction 1:1 in the IpgC/IpaB complex and the multi-functional nature of IpgC under different T3SS states.

BackgroundThis study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques.Methodology/principal findingsFecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2-5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques. A total of 96.3% of the children were infested with at least one intestinal parasite. The most prevalent parasites were Giardia intestinalis (79.5%), Ascaris lumbricoides (68.3%) and Trichuris trichiura (68.0%). For all parasites studied, real-time PCR showed higher detection rates compared to microscopy (G. intestinalis [77.6% (n = 318) versus 20.9% (n = 86)], Entamoeba histolytica [15.8% (n = 65) versus 1.9% (n = 8)] and A. lumbricoides [64.1% (n = 263) versus 50.7% (n = 208)]). Among the different variables assessed in the study, age of 4 to 5 years (AOR = 4.61; 95% CI, (1.35-15.77)) and primary and secondary educational level of the mother (AOR = 12.59; 95% CI, (2.76-57.47); AOR = 9.17; 95% CI, (2.12-39.71), respectively) were significantly associated with IPIs. Children drinking untreated water was associated with infestation with G. intestinalis (AOR = 1.85; 95% CI, (1.1-3.09)) and E. histolytica (AOR = 1.9; 95% CI, (1.07-3.38)). E. histolytica was also associated with moderately stunted children (AOR = 0.37; 95% CI, 0.2-0.71). Similarly, children aged between 4 and 5 years (AOR = 3.2; 95% CI (2.04-5.01)) and living on noncemented soil types (AOR = 1.85; 95% CI, (1.18-2.09)) were associated with T. trichiura infestation.Conclusions/significanceThe prevalence of IPIs is substantial in the studied areas in both stunted and control children, despite the large-scale drug administration of antiparasitic drugs in the country. This high prevalence of IPIs warrants further investigation. Improved health education, environmental sanitation and quality of water sources should be provided.

This paper presents the study of four gypsum mixtures, focusing on the role of both inorganic and organic additives and on the micro-structural features and mechanical properties. Additives have been chosen among those most reported in historical recipes, for example magnesia, lime putty, rabbit glue. The selected mixes refer to gypsum-based materials used in artworks manufacture, such as plasters, mouldings, stuccoworks, pastiglia. Blank reference materials were prepared on purpose according to the specific recipe, in order to verify the final composition and to highlight the hardening mechanisms and the formation of setting compounds. The chemical composition was related to workability properties and final mechanical resistance and the action of additives as retardants was studied with interesting results. For instance, MgO imparts good properties to the mechanical features, especially with regard to the compressive strength characteristics.

The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The functionality of CwaS/R proteins as a TCS has been demonstrated by biochemical analysis. It is involved in the transcriptional regulation of several genes of the PG biosynthesis. Analysis of the muropeptides of PG in mutants allowed us to re-annotate LSEI_0221 as a putative L,D-carboxypeptidase (LdcA). The absence of this protein coincided with a decrease of two surface antigens: LSEI_0020, corresponding to p40 or msp2 whose implication in the host epithelial homeostasis has been recently studied, and LSEI_2029 which has never been functionally characterized. The inactivation of each of these three genes induces susceptibility to antimicrobial peptides (hBD1, hBD2, and CCL20), which could be the main cause of the gut establishment deficiency. Thus, this operon is necessary for the presence of two surface antigens and for a suitable cell wall architecture.

El reconocimiento de la dinámica morfosedimentaria de los espacios costeros constituye un elemento de interés, a fin de comprender la acción de los agentes y procesos involucrados en la constitución del paisaje. De allí que la investigación planteó precisar los rasgos morfosedimentarios de playa San Francisquito, en el litoral mirandino venezolano. Se sustentó en tres fases investigativas: 1) campo: recolección de sedimentos superficiales cada 100 metros en las distintas posiciones del perfil de playa, y registro de parámetros morfodinámicos del oleaje; 2) laboratorio: análisis de las arenas en sus parámetros físicos (textura del material, parámetros de la distribución granulométrica) y químicos (contenido de CaCO3, fracción de minerales pesados y livianos); y 3) oficina: análisis estadístico de los datos obtenidos. El depósito presenta una forma elongada, con arenas medias (berma) y gruesas (vaivén y la rompiente), moderadamente seleccionadas y con distribución leptocúrtica; mineralógicamente compuesto por el >80% CaCO3, así como el 8% de fracción liviana, con cuarzo de bordes subangulares a subredondeados, y en promedio el 6% de minerales pesados. El oleaje presenta alturas de 28,83 cm y velocidad de 1,52 cm/s. Los bioclástos provienen de la barrera arrecifal que flanquea el depósito, así como en el banco de La Tortuga, ubicado a unos 79 km al NE. Ideas destacadas: artículo de investigación, mediante el cual se caracterizan los rasgos morfosedimentarios manifiestos en la configuración de la playa San Francisquito, ubicada en el litoral mirandino, en la fachada Caribe de Venezuela.

Nowadays, technology makes it possible to admire objects and artworks exhibited all over the world remotely. We have been able to appreciate this convenience even more in the last period, in which the pandemic has forced us into our homes for a long time. However, visiting art sites in person remains a truly unique experience. Even during on-site visits, technology can help make them much more satisfactory, by assisting visitors during the fruition of cultural and artistic resources. To this aim, it is necessary to monitor the active user for acquiring information about their behavior. We, therefore, need systems able to monitor and analyze visitor behavior. The literature proposes several techniques for the timing and tracking of museum visitors. In this article, we propose a novel approach to indoor tracking that can represent a promising and non-expensive solution for some of the critical issues that remain. In particular, the system we propose relies on low-cost equipment (i.e., simple badges and off-the-shelf RGB cameras) and harnesses one of the most recent deep neural networks (i.e., Faster R-CNN) for detecting specific objects in an image or a video sequence with high accuracy. An experimental evaluation performed in a real scenario, namely, the “Exhibition of Fake Art” at Roma Tre University, allowed us to test our system on site. The collected data has proven to be accurate and helpful for gathering insightful information on visitor behavior.