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Membrane-bound pyrophosphatases (M-PPases) are homodimeric primary ion pumps that couple the transport of Na + - and/or H + across membranes to the hydrolysis of pyrophosphate. Their role in the virulence of protist pathogens like Plasmodium falciparum makes them an intriguing target for structural and functional studies. Here, we show the first structure of a K + -independent M-PPase, asymmetric and time-dependent substrate binding in time-resolved structures of a K + -dependent M-PPase and demonstrate pumping-before-hydrolysis by electrometric studies. We suggest how key residues in helix 12, 13, and the exit channel loops affect ion selectivity and K + -activation due to a complex interplay of residues that are involved in subunit-subunit communication. Our findings not only explain ion selectivity in M-PPases but also why they display half-of-the-sites reactivity. Based on this, we propose, for the first time, a unified model for ion-pumping, hydrolysis, and energy coupling in all M-PPases, including those that pump both Na + and H + ., (© 2024. The Author(s).)

Deleterious mutations in the X-linked Patched domain-containing 1 (PTCHD1) gene may account for up to 1% of autism cases. Despite this, the PTCHD1 protein remains poorly understood. Structural similarities to Patched family proteins point to a role in sterol transport, but this hypothesis has not been verified experimentally. Additionally, PTCHD1 has been suggested to be involved in Hedgehog signalling, but thus far, the experimental results have been conflicting. To enable a variety of biochemical and structural experiments, we developed a method for expressing PTCHD1 in Spodoptera frugiperda cells, solubilising it in glycol-diosgenin, and purifying it to homogeneity. In vitro and in silico experiments show that PTCHD1 function is not interchangeable with Patched 1 (PTCH1) in canonical Hedgehog signalling, since it does not repress Smoothened in Ptch1 -/- mouse embryonic fibroblasts and does not bind Sonic Hedgehog. However, we found that PTCHD1 binds cholesterol similarly to PTCH1. Furthermore, we identified 13 PTCHD1-specific protein interactors through co-immunoprecipitation and demonstrated a link to cell stress responses and RNA stress granule formation. Thus, our results support the notion that despite structural similarities to other Patched family proteins, PTCHD1 may have a distinct cellular function.

Objectives:: to describe the development and validation process of a scale to measure the nurses' perception of the activities that contribute to nursing care quality., Method:: methodological study based on a literature review, the opinion of experts and the experience of study investigators. An instrument was designed containing six dimensions and 25 items, applied as a questionnaire to 775 nurses from a hospital in northern Portugal, from May to July 2014. The instrument validation used an exploratory factor analysis and an internal consistency assessment of each factor/dimension., Results:: the factor analysis indicated the need to adjust the original composition of the scale, which then received one more dimension, totaling seven dimensions and the same 25 items, and presented a high internal consistency (Cronbach's alpha of 0.940)., Conclusion:: the final version of the scale presents adequate psychometric properties, with potential use in future studies.

In recent studies, we showed that synthetic phosphoethanolamine (PHO-S) has a great potential for inducing cell death in several tumor cell lines without damage to normal cells. However, its cytotoxic effect and selectivity against tumor cells could increase with encapsulation in cationic liposomes, such as dioctadecyldimethylammonium chloride (DODAC), due to electrostatic interactions between these liposomes and tumor cell membranes. Our aim was to use cationic liposomes to deliver PHO-S and to furthermore maximize the therapeutic effect of this compound. DODAC liposomes containing PHO-S (DODAC/PHO-S), at concentrations of 0.3-2.0 mM, prepared by ultrasonication, were analyzed by scanning electron microscopy (SEM) and dynamic light scattering. The cytotoxic effect of DODAC/PHO-S on B16F10 cells, Hepa1c1c7 cells, and human umbilical vein endothelial cells (HUVECs) was assessed by MTT assay. Cell cycle phases of B16F10 cells were analyzed by flow cytometry and the morphological changes by SEM, after treatment. The liposomes were spherical and polydisperse in solution. The liposomes were stable, presenting an average of ∼ 50% of PHO-S encapsulation, with a small reduction after 40 days. DODAC demonstrated efficient PHO-S delivery, with the lowest values of IC50% (concentration that inhibits 50% of the growth of cells) for tumor cells, compared with PHO-S alone, with an IC50% value of 0.8 mM for B16F10 cells and 0.2 mM for Hepa1c1c7 cells, and without significant effects on endothelial cells. The Hepa1c1c7 cells showed greater sensitivity to the DODAC/PHO-S formulation when compared to B16F10 cells and HUVECs. The use of DODAC/PHO-S on B16F10 cells induced G2/M-phase cell cycle arrest, with the proportion significantly greater than that treated with PHO-S alone. The morphological analysis of B16F10 cells by SEM showed changes such as "bleb" formation, cell detachment, cytoplasmic retraction, and apoptotic bodies after DODAC/PHO-S treatment. Cationic liposomal formulation for PHO-S delivery promoted cytotoxicity more selectively and effectively against B16F10 and Hepa1c1c7 cells. Thus, the DODAC/PHO-S liposomal formulation presents great potential for preclinical studies.

Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection.