Characterization of the interaction between the Sec61 translocon complex and ppαF using optical tweezers.

The Sec61 translocon allows the translocation of secretory preproteins from the cytosol to the endoplasmic reticulum lumen during polypeptide biosynthesis. These proteins possess an N-terminal signal peptide (SP) which docks at the translocon. SP mutations can abolish translocation and cause diseases, suggesting an essential role for this SP/Sec61 interaction. However, a detailed biophysical characterization of this binding is still missing. Here, optical tweezers force spectroscopy was used to characterize the kinetic parameters of the dissociation process between Sec61 and the SP of prepro-alpha-factor. The unbinding parameters including off-rate constant and distance to the transition state were obtained by fitting rupture force data to Dudko-Hummer-Szabo models. Interestingly, the translocation inhibitor mycolactone increases the off-rate and accelerates the SP/Sec61 dissociation, while also weakening the interaction. Whereas the translocation deficient mutant containing a single point mutation in the SP abolished the specificity of the SP/Sec61 binding, resulting in an unstable interaction. In conclusion, we characterize quantitatively the dissociation process between the signal peptide and the translocon, and how the unbinding parameters are modified by a translocation inhibitor.

Perchlorate and chlorate assessment in drinking water in northern Chilean cities.

Perchlorate and chlorate are endocrine disruptors considered emerging contaminants (ECs). Both oxyanions are commonly associated with anthropogenic contamination from fertilizers, pesticides, explosives, and disinfection byproducts. However, the soils of the Atacama Desert are the most extensive natural reservoirs of perchlorate in the world, compromising drinking water sources in northern Chile. Field campaigns were carried (2014-2018) to assess the presence of these ECs in the water supply networks of twelve Chilean cities. Additionally, the occurrence of perchlorate, chlorate and other anions typically observed in drinking water matrices of the Atacama Desert (i.e., nitrate, chloride, sulfate) was evaluated using a Spearman correlation analysis to determine predictors for perchlorate and chlorate. High concentrations of perchlorate (up to 114.48 µg L-1) and chlorate (up to 9650 µg L-1) were found in three northern cities. Spatial heterogeneities were observed in the physicochemical properties and anion concentrations of the water supply network. Spearman correlation analysis indicated that nitrate, chloride, and sulfate were not useful predictors for the presence of perchlorate and chlorate in drinking water in Chile. Hence, this study highlights the need to establish systematic monitoring, regulation, and treatment for these EC of drinking water sources in northern Chilean cities for public health protection.

Modeling of Microneedle Arrays in Transdermal Drug Delivery Applications.

The use of computational tools for the development of technologies in fields such as medicine and engineering has facilitated the process of designing new components and devices for these areas. In this work, two proposals focused on a hollow microneedle array (MNA) for the administration of an analgesic drug are shown and evaluated by means of a computational fluid dynamics (CFD) simulation distributed in three stages. In the first stage, the behavior of lidocaine through the MNA was evaluated as a workflow. Then, the possible entry of the drug into the organism, which was established as a porous aqueous medium, was modeled. Finally, a joint simulation was performed to understand the general behavior in the interaction between the outflow of an MNA and the body to which lidocaine is administered. The input parameters to the simulation were set at a velocity of 0.05 m∙s-1, at a pressure of 2000 Pa, the dominant behavior was defined as laminar flow, and a resistive pressure at the inlet of 400 Pa. Our results indicate that the vertical flow exhibits a better fluid distribution across the MNAs and favorable infiltration behavior, representing better delivery of the analgesic to the skin capillaries.

Quality of Life of Chilean Breast Cancer Survivors: Multicentric Study / Qualidade de Vida de Sobreviventes de Câncer de Mama do Chile: Estudo Multicêntrico / Calidad de Vida de Sobrevivientes de Cáncer de Mama de Chile: Estudio Multicentrico

Introduction: As breast cancer survivorship rates increase, so does the necessity to improve survivors' health-related quality of life (HRQoL). Objective: To analyze HRQoL among Chilean breast cancer survivors, in general and considering geographic location. In addition, to correlate HRQoL with age, education level and body mass index (BMI). Method: Cross-sectional observational study which included 125 female breast cancer survivors from three public hospitals in three Chilean Macroregions: Central, North Central, and South. The EORTC Questionnaires, QLQ-C30 and QLQ-BR23, and sociodemographic and clinical records were applied. Results: The mean age was 56.1 (±11.9) years with a HRQoL summary score of 67.6 (21.9). HRQoL was reduced mainly in emotional functioning, pain, and insomnia. Fatigue, dyspnea, appetite loss, constipation, financial difficulties, breast and arm symptoms were also reported. The women from the South Macroregion Hospital presented the worst HRQoL scores for most of the domains [general health, functioning (physical, emotional, cognitive and social), fatigue, and nausea], p<0.001. The summary score of HRQoL was correlated to age (Spearman ́s rho=0.202, p=0.033), BMI (rho=-0.341, p<0.001), and education level (rho=0.310, p=0.001). Conclusion: Women from three Macroregions showed differences in HRQoL. The latter correlated to age, BMI, and education level. Considering the high presence of symptoms, it is necessary to improve survivorship care plans, providing access to rehabilitation in the continuum of care.

Introdução: À medida que as taxas de sobrevivência do câncer de mama aumentam, também aumenta a necessidade de melhorar a qualidade de vida relacionada à saúde (QVRS) dos sobreviventes. Objetivo: Analisar a QVRS em geral e considerando a localização geográfica entre sobreviventes de câncer de mama chilenas. Além disso, correlacionar a QVRS com idade, nível educacional e índice de massa corporal (IMC). Método: Estudo observacional transversal que incluiu 125 mulheres sobreviventes de câncer de mama de três hospitais públicos em três Macrorregiões chilenas: Central, Norte-Central e Sul. Foram utilizados os Questionários EORTC QLQ-C30 e QLQ-BR23 e os registros sociodemográficos e clínicos. Resultado: A média de idade foi de 56,1 (±11,9) anos com escore resumido de QVRS de 67,6 (21,9). A QVRS estava reduzida principalmente no funcionamento emocional, dor e insônia. Fadiga, dispneia, perda de apetite, constipação, dificuldades financeiras, sintomas de braço e mama também foram mencionados. As mulheres do hospital da Macrorregião Sul apresentaram os piores escores de QVRS para a maioria dos domínios [saúde geral, funcionamento (físico, emocional, cognitivo e social), fadiga e náusea], p<0,001. A pontuação geral de QVRS esteve correlacionada com idade (rho de Spearman=0,202, p=0,033), IMC (rho=-0,341, p<0,001) e nível educacional (rho=0,310, p=0,001). Conclusão: As mulheres das três Macrorregiões apresentaram diferenças na QVRS.Esta última se correlacionou com idade, IMC e nível educacional. Considerando a alta presença de sintomas, há necessidade de aprimoramento dos planos de atenção à sobrevivência, possibilitando acesso à reabilitação no contínuo do cuidado

Introducción: A medida que aumentan las tasas de supervivencia al cáncer de mama, también aumenta la necesidad de mejorar la calidad de vida relacionada con la salud (CdV) de las sobrevivientes. Objetivo: Analizar la CdV entre supervivientes chilenas de cáncer de mama, en general y considerando ubicación geográfica. Además, correlacionar CdV con edad, nivel educacional e índice de masa corporal (IMC). Método: Estudio observacional transversal que incluyó a 125 mujeres sobrevivientes de cáncer de mama de tres Hospitales públicos de tres Macrorregiones de Chile: Centro, Centro Norte y Sur. Se utilizaron los Cuestionarios EORTC QLQ-C30 y QLQ-BR23, historias sociodemográficas y clínicas. Resultados: La edad media fue de 56,1 (±11,9) años con una puntuación resumida de CdV de 67,6 (21,9). La CdV estuvo disminuida principalmente en funcionamiento emocional, dolor e insomnio. Fatiga, disnea, pérdida de apetito, estreñimiento, dificultades financieras, síntomas de brazo y mama también fueron reportados. Las mujeres del hospital de la Macrorregión Sur presentaron las peores puntuaciones de calidad de vida en la mayoría de los dominios [salud general, funcionamiento (físico, emocional, cognitivo y social), fatiga y nausea], p<0,001. El puntaje de CdV estuvo correlacionado con edad (rho de Spearman =0,202, p=0,033), IMC (rho=-0,341, p<0,001) y nivel educacional (rho=0,310, p=0,001). Conclusión: Las mujeres pertenecientes a tres regiones presentaron diferencias en la CdV.Esta última se correlacionó con edad, IMC y nivel educacional. Considerando la elevada presencia de síntomas, es necesario mejorar los planes de atención a las sobrevivientes, posibilitando acceso a rehabilitación en el continuo de los cuidados.

Chlorate addition enhances perchlorate reduction in denitrifying membrane-biofilm reactors.

Perchlorate is a widespread drinking water contaminant with regulatory standards ranging from 2 to 18 µg/L. The hydrogen-based membrane-biofilm reactor (MBfR) can effectively reduce perchlorate, but it is challenging to achieve low-µg/L levels. We explored chlorate addition to increase the abundance of perchlorate-reducing bacteria (PRB) and improve removals. MBfR reactors were operated with and without chlorate addition. Results show that chlorate doubled the abundance of putative PRB (e.g., Rhodocyclales) and improved perchlorate reduction to 23 ± 17 µg/L, compared to 53 ± 37 µg/L in the control. Sulfate reduction was substantially inhibited during chlorate addition, but quickly recovered once suspended. Our results suggest that chlorate addition can enhance perchlorate reduction by providing a selective pressure for PRB. It also decreases net sulfate reduction. KEY POINTS: • Chlorate increased the abundance of perchlorate-reducing bacteria • Chlorate addition improved perchlorate removal • Chlorate appeared to suppress sulfate reduction.

Making Waves: Biocatalysis and Biosorption: Opportunities and Challenges Associated with a New Protein-Based Toolbox for Water and Wastewater Treatment.

New water and wastewater treatment technologies are required to meet the demands created by emerging contaminants and resource recovery needs, yet technology development is a slow and uncertain process. Through evolution, nature has developed highly selective and fast-acting proteins that could help address these issues, but research and application have been limited, often due to assumptions about stability and economic feasibility. Here we highlight the potential advantages of cell-free, protein-based water and wastewater treatment processes (biocatalysis and biosorption), evaluate existing information about their economic feasibility, consider when a protein-based treatment process might be advantageous, and highlight key research needs.

Characterization of the number, distribution and pertinence of pediatricians in Colombia. 2017 / Caracterización de la cantidad, distribución y pertinencia de los pediatras en Colombia. 2017

Abstract Introduction: Health human resources estimation and planning in the country require analyzing the relationship between socio-demographic and epidemiological aspects of the population and the supply of health services in different territories. Objective: To analyze the number, distribution and pertinence of pediatricians in Colombia. Materials and methods: Cross-sectional study. Data obtained from different sources were aggregated and refined to obtain a single database that allowed conducting an analysis of the number and distribution of pediatricians in Colombia and, this way, make an approximation of the census of Colombian pediatricians. Results: By 2017, there were 3 398 pediatricians in Colombia. Most pediatricians worked in Bogotá D.C. (35.96%) and in the departments of Antioquia (12.30%) and Valle del Cauca (9.59%). In contrast, in the departments of Vichada and Vaupés, there were no pediatricians and this service was not available. Conclusion: The distribution of pediatricians in Colombia depends more on the dynamics of healthcare service providers than on the health care needs of children in the different regions of the country. Therefore, the implementation of new policies aiming at achieving a better distribution of the available resources is required to strengthen local authorities and to regulate the provision of pediatric care services throughout the country according to the multiple health needs of each region.

Resumen Introducción. La estimación y planificación del recurso humano en salud a nivel nacional requiere analizar las relaciones entre la situación sociodemográfica y epidemiológica de las diferentes poblaciones y la oferta de servicios de salud en los territorios que ocupan. Objetivo. Analizar la cantidad, la distribución y la pertinencia de pediatras en Colombia. Materiales y métodos. Estudio trasversal. Los datos obtenidos de distintas fuentes fueron agregados y depurados para obtener una base de datos única que permitió analizar la cantidad y distribución de pediatras en el país y, de esta forma, realizar una aproximación del censo de pediatras en Colombia. Resultados. Para 2017 había 3 398 pediatras en Colombia. Además, la mayoría ejercía en Bogotá D.C. (35.96%) y en los departamentos de Antioquia (12.30%) y Valle del Cauca (9.59%), mientras que en los departamentos de Vichada y Vaupés no se reportó la presencia de estos especialistas o la prestación de sus servicios. Conclusión. La distribución de pediatras en Colombia responde más a la dinámica de los prestadores de servicios de salud que a las necesidades de la población infantil en los diferentes territorios, por lo que es necesario plantear nuevas políticas que permitan una mejor redistribución de los recursos disponibles y, de esta forma, fortalecer a los entes territoriales y regular la prestación de los servicios pediátricos en todo el país de acuerdo a las múltiples necesidades en salud de las diferentes regiones.

Detection of Zika Virus and Human Papilloma Virus in Cervical Cytology Samples using Two Real Time PCR Based Techniques in Ecuadorian Women diagnosed with ASCUS.

OBJECTIVE: Atypical Squamous Cells of Undetermined Significance(ASCUS) is the most reported result on pap smears. It is most commonly related to Human Papillomavirus (HPV) infections. However, other pathogens (EBV, Chlamydia) have been reported on cervical samples with abnormal results. Zika virus(ZIKV) has been found to induce cellular abnormalities on different tissues and its presence has been identified on genital secretions. METHODS: Two real-time PCR has been made on cervical samples from the gynecological service of a third level hospital on Guayaquil-Ecuador. This work was part of a bigger study of ZIKV presence on different body fluids. RESULTS: From 89 samples obtained, 19 received an ASCUS result. From these 5 were positive for ZIKV and 5 were positive for HPV, there were no co infections. CONCLUSION: Given the presence of ZIKV RNA and the absence of HPV DNA on cervical samples diagnosed as ASCUS, it might be plausible that ZIKV could be a triggering factor for the induction of cellular changes observed on these cells.

Perchlorate contamination in Chile: Legacy, challenges, and potential solutions.

This paper reviews the unique situation of perchlorate contamination in Chile, including its sources, presence in environmental media and in the human population, and possible steps to mitigate its health impacts. Perchlorate is a ubiquitous water contaminant that inhibits thyroid function. Standards for drinking water range from 2 to 18 µg L-1 in United States and Europe. A major natural source of perchlorate contamination is Chile saltpeter, found in the Atacama Desert. High concentrations of perchlorate have presumably existed in this region, in soils, sediments, surface waters and groundwaters, for millions of years. As a result of this presence, and the use of Chile saltpeter as a nitrogen fertilizer, perchlorate in Chile has been found at concentrations as high as 1480 µg L-1 in drinking water, 140 µg/kg-1 in fruits, and 30 µg L-1 in wine. Health studies in Chile have shown concentrations of 100 µg L-1 in breast milk and 20 µg L-1 in neonatal serum. It is important to acknowledge perchlorate as a potential health concern in Chile, and assess mitigation strategies. A more thorough survey of perchlorate in Chilean soils, sediments, surface waters, groundwaters, and food products can help better assess the risks and potentially develop standards. Also, perchlorate treatment technologies should be more closely assessed for relevance to Chile. The Atacama Desert is a unique biogeochemical environment, with millions of years of perchlorate exposure, which can be mined for novel perchlorate-reducing microorganisms, potentially leading to new biological treatment processes for perchlorate-containing waters, brines, and fertilizers.

Single molecule force spectroscopy reveals the effect of BiP chaperone on protein folding.

BiP (Immunoglobulin Binding Protein) is a member of the Hsp70 chaperones that participates in protein folding in the endoplasmic reticulum. The function of BiP relies on cycles of ATP hydrolysis driving the binding and release of its substrate proteins. It still remains unknown how BiP affects the protein folding pathway and there has been no direct demonstration showing which folding state of the substrate protein is bound by BiP, as previous work has used only peptides. Here, we employ optical tweezers for single molecule force spectroscopy experiments to investigate how BiP affects the folding mechanism of a complete protein and how this effect depends on nucleotides. Using the protein MJ0366 as the substrate for BiP, we performed pulling and relaxing cycles at constant velocity to unfold and refold the substrate. In the absence of BiP, MJ0366 unfolded and refolded in every cycle. However, when BiP was added, the frequency of folding events of MJ0366 significantly decreased, and the loss of folding always occurred after a successful unfolding event. This process was dependent on ATP and ADP, since when either ATP was decreased or ADP was added, the duration of periods without folding events increased. Our results show that the affinity of BiP for the substrate protein increased in these conditions, which correlates with previous studies in bulk. Therefore, we conclude that BiP binds to the unfolded state of MJ0366 and prevents its refolding, and that this effect is dependent on both the type and concentration of nucleotides.

Cloning of novel cellulases from cellulolytic fungi: heterologous expression of a family 5 glycoside hydrolase from Trametes versicolor in Pichia pastoris.

Total cDNA isolated from cellulolytic fungi cultured in cellulose was examined for the presence of sequences encoding for endoglucanases. Novel sequences encoding for glycoside hydrolases (GHs) were identified in Fusarium oxysporum, Ganoderma applanatum and Trametes versicolor. The cDNA encoding for partial sequences of GH family 61 cellulases from F. oxysporum and G. applanatum shares 58 and 68% identity with endoglucanases from Glomerella graminicola and Laccaria bicolor, respectively. A new GH family 5 endoglucanase from T. versicolor was also identified. The cDNA encoding for the mature protein was completely sequenced. This enzyme shares 96% identity with Trametes hirsuta endoglucanase and 22% with Trichoderma reesei endoglucanase II (EGII). The enzyme, named TvEG, has N-terminal family 1 carbohydrate binding module (CBM1). The full length cDNA was cloned into the pPICZαB vector and expressed as an active, extracellular enzyme in the methylotrophic yeast Pichia pastoris. Preliminary studies suggest that T. versicolor could be useful for lignocellulose degradation.