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Does the El Niño-Southern Oscillation Affect the Combined Impact of the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation on the Precipitation and Surface Air Temperature Variability over South America?

Kayano, Mary | 2022

Previous studies have shown that the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) have combined effects on the precipitation (PRP) variability over South America. The combined impacts have been assessed considering four mean states as the averages of the variable anomalies during sub-periods overlapping time intervals of the PDO and AMO phases. Since these sub-periods include years under El Niño-Southern Oscillation (ENSO) extremes, the extent to which these years’ occurrence affects the averaged anomaly patterns during different mean states is investigated. The analyses are done for the PRP and surface air temperature (SAT) during the austral winter (June to August) and summer (December to February) of the 1901–2014 period using a composite technique. The nonlinear ENSO response in each mean state for a variable corresponds to the sum of the anomaly composites of the El Niño and La Niña events. In each mean state, the nonlinear PRP and SAT anomalies are not negligible and show similar patterns of the corresponding mean state, with larger magnitudes. For both seasons and all mean states, these similarities are more pronounced for SAT than for PRP. Thus, the ENSO variability affects the mean state’s PRP and SAT anomaly patterns in different ways. As far as we know, analyses of the nonlinear ENSO response of the South American climate during distinct mean states were not performed before. Our results also indicate that the ENSO variability should be considered in the studies of the low-frequency modes and their effects on the mean state over South America. The results presented could be relevant for climate monitoring and modeling studies.

The prevalence of Chlamydia psittaci in confiscated Psittacidae in Colombia

Ruiz Laiton, Alejandra | 2022

Chlamydia psittaci is a highly zoonotic bacteria distributed worldwide; it is responsible for psittacosis, one of the most important infectious diseases affecting the Psittacidae, mostly parrots. This work was aimed at determining C. psittaci prevalence and genotype in 177 parrots confiscated in Colombia; cloacal swab (166) and faecal (177) samples were analysed from birds confiscated and housed in a Temporary Wildlife Reception Centre (Centro de Reception de Fauna Temporal). Conventional PCR was run on the samples for amplifying the MOMP gene and then the ompA gene. The C. psittaci genotype A was found in 81.3 % (144/177) of the birds analysed. Cloacal swabs accounted for 129/166 (77.7 %) positive samples and faecal matter for 53/177 (29.9 %), 38 birds proving positive for both types of sample; there was an 8.15 times greater probability of detection for cloacal swabs compared to faecal swabs (p < 0.05). Clinical examination findings were correlated with the animals’ positivity for cloacal swabs, faecal matter or both, finding a statistically significant relationship with low respiratory rate (p < 0.05) and broken plumage for cloacal swab sample results (p < 0.1). Even though 85 % seroprevalence has previously been reported in Colombia using indirect ELISA, this study reports for the first time C. psittaci genotype A endemicity in psittacines in captivity in Colombia using molecular techniques, considering the zoonotic risk involved in having these birds as pets.

A regional PECS node built from place-based social-ecological sustainability research in Latin America and the Caribbean

Calderón-Contreras, Rafael | 2022

Sustainability requires a combination of meaningful co-production of locally relevant solutions, synthesis of insights gained across regions, and increased cooperation between science, policy and practice. The Programme for Ecosystem Change and Society (PECS) has been coordinating Place-Based Social-Ecological Sustainability Research (PBSESR) across the globe and emphasizes the need for regional scientific nodes from diverse biocultural regions to inform sustainability science and action. In this paper, we assess the strengths of the PBSESR communities in Latin America and the Caribbean (LAC). We provide an overview of PBSESR literature associated with this region and highlight the achievements of two prominent regional networks: The Social-Ecological Systems and Sustainability Research Network from Mexico (SocioEcoS) and the South American Institute for Resilience and Sustainability Studies from Uruguay (SARAS Institute). Finally, we identify the potential in these nodes to constitute a regional PECS node in Latin America and discuss the capacity needed to ensure such function. The results of the literature review show that while still loosely interconnected across the region, networks play key roles in connecting otherwise cloistered teams and we illustrate how the SocioEcoS network (focusing on transdisciplinary co-production of knowledge towards sustainability) and the SARAS Institute (focusing on innovative approaches for looking at complex social-ecological problems, rooted in slow science and arts) operate as key connectors in the region. We conclude that these organizations combined can embody a Latin American node for PECS, and would thereby not only contribute to regional but also global capacities to advance the sustainability agenda.

Practical guide for the use of medical evidence in scientific publication: Recommendations for the medical student: Narrative review

Lozada-Martínez, Iván David | 2021

Currently, the adaptation of scientific evidence in clinical problem solving is based on the evidence-based medicine method. Medical students and health professionals should have an adequate knowledge of this method and thus provide adequate health care and increasingly provide high quality scientific publications that can be subsequently integrated in different clinical scenarios. Several scales and tools have been proposed as guides to recognize the different levels of quality of the available evidence, their degrees of recommendation and the biases and fallacies that may occur both in the clinical and research areas, with the aim of identifying the best available evidence. However, few students and professionals are aware of them and make proper use of them. Therefore, it is necessary to synthesize these tools in an understandable and practical way.

Indigenous Family Labor in Agroforestry Systems in the Context of Global Transformations: The Case of the Inga and Camëntsá Communities in Putumayo, Colombia

Vandreé Julián, Palacios Bucheli | 2021

The Camëntsá and Inga indigenous communities still rely on agroforestry systems for their livelihood attainment, although globalization effects have also reached their settlements. Agroforestry systems, especially home gardens, are experiencing reduced size and species diversity and therefore gradually disappearing. This research aims to determine the indigenous family labor contribution to agroforestry systems as a strategy to secure their livelihoods. The methods include a census, household survey, interviews with key informants, and direct observation. Family labor contributes to reducing production costs in agroforestry systems. Three groups of households were identified from the cluster analysis to determine the family labor contribution: smaller, medium-sized, and larger farms. The smaller farms register better economic indicators compared to the other two groups. In addition, they show a positive cost–benefit ratio and profitability, which is explained by lower production costs compared to the gross income generated. Although larger farms have higher gross revenues, these households also assume higher production costs and incur higher input costs. Medium-sized farms face the worst scenario. There is a relationship between the use of family labor and the achievement of livelihoods related to economic indicators and biodiversity and the variety of species harvested on farms and used for self-consumption. Family labor helps to ensure local food security and generate income.

Spatio-Temporal Variability of Hydroclimatology in the Upper Cauca River Basin in Southwestern Colombia: Pre- and Post-Salvajina Dam Perspective

Cerón, Wilmar L. | 2021

The Cauca River rises in the Colombian Andes and is the main tributary of the Magdalena River, which drains to the Caribbean Sea. The La Balsa station monitors the Upper Cauca basin and is located just downstream of La Salvajina hydroelectric facility. At this station, the discharge time series for November–January during 1950–2019 shows a statistically significant downward break, and change of distribution after 1986 has been documented after La Salvajina started operation. We assessed the spatio-temporal variability of hydroclimatology in the upper Cauca River basin during the pre-and post-Salvajina dam periods to better understand this break. Post-Salvajina, low (high) discharge events are linked to negative (positive) precipitation and soil moisture anomalies that are greater in magnitude and extension than those recorded in the pre-Salvajina period in response to the more intense El Niño events (more intense and frequent central La Niña events) after 1986. Therefore, it is necessary to consider possible future rainfall scenarios and non-infrastructure measures (i.e., reforestation, territorial planning, integrated watershed management, etc.) to mitigate floods and droughts impacts. The contribution of this study is to provide evidence for the need for foresight in the design of any structural or non-structural flood measures.

Composición nutricional, niveles de nitratos y nitritos del pasto Kikuyo y su influencia en producción de leche

Camacho, Jairo | 2022

Objetivo. Establecer variaciones de la composición nutricional e incidencia de los contenidos de nitratos y nitritos en el pasto Kikuyo (Cenchrus clandestinus (Hochst. ex Chiov.)Morrone), procedente de cuatro veredas: Peña Blanca, Sirigay, Sabaneca y Quintoque, en épocas seca y de lluvia del municipio de San Miguel de Sema – Boyacá. Materiales y métodos. Parámetros de caracterización nutricional fueron asociados a un análisis de varianza, usando la prueba de Tukey como comparación de medias. Resultados. En la materia seca, se destacan altos contenidos promedios de proteína total (23.48% +/- 3.71), de fibra en detergente neutra (60.86% +/- 3.03), importantes niveles de degradabilidad de la MS en los diferentes tiempos, indicando 62.97% +/- 3.74 para el tiempo 48; así como valores disminuidos en niveles de lignina 4.25% +/- 0.5; de carbohidratos no estructurales (11.44% +/-2.43) y de la relación carbohidratos no estructurales:proteína degradada en rumen (0.84 +/- 0.16). Los niveles de nitratos con un promedio de 2977 ppm +/- 2061, presentaron diferencias significativas para las épocas y veredas, para la época seca en las diferentes veredas el contenido promedio fue de 4728 ppm, siendo 3.9 mayor comparativamente con la época de lluvia. Los niveles de nitritos presentaron contenidos promedios de 2.97 ppm de la MS, contenidos muy disminuidos para ser relacionados como tóxicos. Conclusiones. Se mostró un desbalance en la relación proteína:energía como limitante en la zona para la producción de leche. Los niveles de nitratos fueron considerados como potencialmente tóxicos.

Missing data estimation in extreme rainfall indices for the Metropolitan area of Cali - Colombia: An approach based on artificial neural networks

Ocampo-Marulanda, Camilo | 2021

Changes observed in the current climate and projected for the future significantly concern researchers, decision-makers, and the general public. Climate indices of extreme rainfall events are a trend assessment tool to detect climate variability and change signals, which have an average reliability at least in the short term and given climatic inertia. This paper shows 12 climate indices of extreme rainfall events for annual and seasonal scales for 12 climate stations between 1969 to 2019 in the Metropolitan area of Cali (southwestern Colombia). The construction of the indices starts from daily rainfall time series, which although have between 0.5% and 5.4% of missing data, can affect the estimation of the indices. Here, we propose a methodology to complete missing data of the extreme event indices that model the peaks in the time series. This methodology uses an artificial neural network approach known as Non-Linear Principal Component Analysis (NLPCA). The approach reconstructs the time series by modulating the extreme values of the indices, a fundamental feature when evaluating extreme rainfall events in a region. The accuracy in the indices estimation shows values close to 1 in the Pearson's Correlation Coefficient and in the Bi-weighting Correlation. Moreover, values close to 0 in the percent bias and RMSE-observations standard deviation ratio. The database provided here is an essential input in future evaluation studies of extreme rainfall events in the Metropolitan area of Cali, the third most crucial urban conglomerate in Colombia with more than 3.9 million inhabitants.

Cervical cancer screening programme attendance and compliance predictors regarding Colombia’s Amazon region

González, Alejandra | 2022

Background Cervical cancer (CC) promotion and prevention (P&P) programmes’ challenge lies in guaranteeing that follow-up strategies have a real impact on reducing CC-related mortality rates. CC P&P programme compliance and coverage rates are relevant indicators for evaluating their success and good performance; however, such indicators’ frequency rates are considerably lower among women living in rural and border areas. This study was aimed at identifying factors associated with CC screening programme attendance for women living in Colombia’s Amazon region. Methods This study (qualitative and quantitative phases) was carried out between September 2015 and November 2016; women residing in the border towns of Leticia and Puerto Nariño participated in it. The first phase (qualitative) involved interviews and focus group discussions; this led to establishing factors related to CC P&P programme attendance which were used in the quantitative phase for designing a survey for determining the strength of association in a logistic regression model. The terms attendance and compliance were considered to apply to women who had followed the 1–1–3 scheme throughout their lives, i.e. a cytology examination every 3 years after receiving two consecutive negative annual cytology results. Results Inclusion criteria were met by 309 women (≥18-year-olds having an active sexual life, having resided in the target community for at least one year); 15.2% had suitable P&P programme follow-up. Screening programme attendance was positively associated with first intercourse after becoming 20 years-old (aOR: 3.87; 1.03–9.50 95%CI; p = 0.045), frequent contraceptive use (aOR: 3.11; 1.16–8.33 95%CI; p = 0.023), awareness of the age to participate in P&P programmes (aOR: 2.69; 1.08–6.68 95%CI; p = 0.032), awareness of cytology’s usefulness in identifying cervical abnormalities (aOR: 2.43; 1.02–5.77 95%CI; p = 0.043) and considering cytology important (aOR: 2.64; 1.12–6.19 95%CI; p = 0.025). Women living in rural areas had a lower probability (aOR 0.43: 0.24–0.79 95%CI; p = 0.006) of adhering to CC P&P programmes. Conclusions This study’s findings suggested the need for including novel strategies in screening programmes which will promote CC P&P activities going beyond hospital outpatient attendance to reach the most remote or widely scattered communities, having the same guarantees regarding access, opportunity and quality. Including education-related activities and stimulating the population’s awareness regarding knowledge about CC prevention could be one of the main tools for furthering the impact of attendance at and compliance with P&P programmes.

Trichomonas vaginalis follow-up and persistence in Colombian women

Hernández-Buelvas, Lauren | 2021

Trichomonas vaginalis (TV), the most common non-viral sexually-transmitted infection is considered a neglected infection and its epidemiology is not well known. This study determined TV-infection dynamics in a retrospective cohort of Colombian women and evaluated associations between risk factors and TV-outcome. TV was identified by PCR. Cox proportional risk models were used for evaluating the relationship between TV-outcome (infection, clearance and persistence) and risk factors (sexually-transmitted infections and sociodemographic characteristics). Two hundred and sixty-four women were included in the study; 26.1% had TV at the start of the study, 40.9% suffered at least one episode of infection and 13.0% suffered more than one episode of TV during the study. Women suffering HPV had a greater risk of TV-infection (aHR 1.59), high viral-load (> 102) for HPV-16 being related to a greater risk of persistent parasite infection; a high viral load (> 102) for HPV-18 and -33 was related to a lower probability of TV-clearance. Ethnicity (afrodescendent/indigenous people: aHR 5.11) and having had more than two sexual partners (aHR 1.94) were related to greater risk of infection, contrasting with women having a background of abortions and lower probability of having TV (aHR 0.50). Women aged 35- to 49-years-old (aHR 2.08), increased years of sexual activity (aHR 1.10), multiple sexual partners (aHR 8.86) and multiparous women (aHR 3.85) led to a greater probability of persistence. Women whose cervical findings worsened had a 9.99 greater probability of TV-persistence. TV distribution was high in the study population; its coexistence with HPV and other risk factors influenced parasite infection dynamics. The results suggested that routine TV detection should be considered regarding populations at risk of infection.

How to combat gram-negative bacteria using antimicrobial peptides: A challenge or an unattainable goal?

Barreto-Santamaría, Adriana | 2021

Antimicrobial peptides (AMPs) represent a promising and effective alternative for combating pathogens, having some advantages compared to conventional antibiotics. However, AMPs must also contend with complex and specialised Gram-negative bacteria envelops. The variety of lipopolysaccharide and phospholipid composition in Gram-negative bacteria strains and species are decisive characteristics regarding their susceptibility or resistance to AMPs. Such biological and structural barriers have created delays in tuning AMPs to deal with Gram-negative bacteria. This becomes even more acute because little is known about the interaction AMP–Gram-negative bacteria and/or AMPs’ physicochemical characteristics, which could lead to obtaining selective molecules against Gram-negative bacteria. As a consequence, available AMPs usually have highly associated haemolytic and/or cytotoxic activity. Only one AMP has so far been FDA approved and another two are currently in clinical trials against Gram-negative bacteria. Such a pessimistic panorama suggests that efforts should be concentrated on the search for new molecules, designs and strategies for combating infection caused by this type of microorganism. This review has therefore been aimed at describing the currently available AMPs for combating Gram-negative bacteria, exploring the characteristics of these bacteria’s cell envelop hampering the development of new AMPs, and offers a perspective regarding the challenges for designing new AMPs against Gram-negative bacteria

La APP U.D.C.A más cerca de la I+D+i

Anzola Montero, German | 2021

Como parte del proceso de innovación e incorporación de nuevas tecnologías en el quehacer universitario, la U.D.C.A adoptó, en este año, el desarrollo de su aplicación, la cual, se caracteriza por ser accesible y con funcionalidad para toda la comunidad universitaria, entre la cual, se encuentra el proceso de investigación y gestión del conocimiento

Molecular diversity of the VP2 of Carnivore protoparvovirus 1 (CPV-2) of fecal samples from Bogotá

Galvis, Cristian Camilo | 2022

Background: Carnivore protoparvovirus 1, also known as canine parvovirus type 2 (CPV-2), is the main pathogen in hemorrhagic gastroenteritis in dogs, with a high mortality rate. Three subtypes (a, b, c) have been described based on VP2 residue 426, where 2a, 2b, and 2c have asparagine, aspartic acid, and glutamic acid, respectively. Objectives: This study examined the presence of CPV-2 variants in the fecal samples of dogs diagnosed with canine parvovirus in Bogotá. Methods: Fecal samples were collected from 54 puppies and young dogs (< 1 year) that tested positive for the CPV through rapid antigen test detection between 2014–2018. Molecular screening was developed for VP1 because primers 555 for VP2 do not amplify, it was necessary to design a primer set for VP2 amplification of 982 nt. All samples that were amplified were sequenced by Sanger. Phylogenetics and structural analysis was carried out, focusing on residue 426. Results: As a result 47 out of 54 samples tested positive for VP1 screening, and 34/47 samples tested positive for VP2 980 primers as subtype 2a (n = 30) or 2b (n = 4); subtype 2c was not detected. All VP2 sequences had the amino acid, T, at 440, and most Colombian sequences showed an S514A substitution, which in the structural modeling is located in an antigenic region, together with the 426 residue. Conclusions: The 2c variant was not detected, and these findings suggest that Colombian strains of CPV-2 might be under an antigenic drift.

Minadores de hojas del aguacate (Lepidoptera: Gracillariidae). Estado actual, Identificación, evaluación de daño y propuesta de manejo

Posada-Flórez, Francisco Javier | 2021

El cultivo de aguacate representa uno de los principales productos agrícolas de Colombia. Durante las últimas dos décadas, el área sembrada se quintuplicó y se ampliaron, notablemente, las zonas de siembra, en especial, para el cultivar Hass. Con el crecimiento de su producción, también se reportan nuevos problemas fitosanitarios, mayormente, por la adopción de sistemas productivos de otras latitudes del mundo, donde no se cuentan con ecosistemas con presencia de lauráceas y otras plantas relacionadas con el aguacate. Dentro de las especies plagas, se registra a los minadores de hojas del orden Lepidoptera, que se caracterizan por desarrollarse y alimentarse dentro de las hojas, cuyo efecto perjudicial, se genera, en principio, cuando son afectadas las poblaciones de sus enemigos naturales. El primer registro documentado de estos insectos en el país, se realizó a partir de muestras colectadas en un cultivo de aguacate cv. Hass, en Villamaría, (Caldas), que presentó una explosión de las poblaciones de minadores, como consecuencia de la aplicación calendario de plaguicidas, con el criterio de proteger de plagas al cultivo, como arañita roja y trips. Con el fin de evitar que se aumente la frecuencia de eventos, como el enunciado, se desarrolló el trabajo actual, el cual, tuvo como objeto presentar el estado actual de los minadores de hoja del aguacate en Colombia, identificación y descripción del daño del minador de hojas del aguacate en serpentina y en ampolla y brindar recomendaciones para su manejo, en las zonas productoras de Colombia

Seroprevalence and risk factors for Leptospira spp. in small ruminants of semi-arid zone in northeastern Colombia

Guzmán Barragán, Blanca Lisseth | 2022

Leptospirosis in small ruminants is an economically important disease that causes important losses by pathologies of the reproductive tract. The present study aimed to estimate the seroprevalence and risk factors associated with Leptospira spp. in small ruminants under traditional husbandry systems. A cross-sectional epidemiological study was carried out in a sample of 1039 animals which included 793 sheep and 245 goats from 49 farms of 10 municipalities of northeastern areas of Colombia. The MAT test using a panel of 13 laboratory serovars was performed to diagnose the Leptospira spp. antibodies in the serum samples of animals. A structured questionnaire was flled in each farm to obtain information on putative risk factors, and its association with Leptospira spp. infection was detected by univariate and multivariate logistic regression. The general seroprevalence showed a rate of 13.9%, the 79.6% of farms showed at least one positive animal, the 14.2% and 0.4% of positive animals showed titers≥1:100 and 1:200, respectively. The seroprevalence in sheep and goats showed a rate of 13.1% and 16.2%, respectively. The most common serovars in positive animals were Autumnalis (3.6%), Tarassovi (3.4%), Bratislava (2.9%), Mini (2.9%), Bataviae (1.4%), Canicola (0.3%), and Grippotyphosa (0.3%). The univariate and multivariate analysis showed as risk factors the absence of housing system (OR=3.412 CI: 1.347–8.152), the absence of quarantine measures to new animals (OR=1.371 CI: 0.943–1.978), and the protective factor identifed was the use of Toggenburg breed (OR=0.571 CI: 0.249–1.074). This exploratory study showed the Leptospira spp. positive small ruminants located in the northeastern areas of Colombia with titer associated with chronic and subclinical infection.

Trend Pattern of Heavy and Intense Rainfall Events in Colombia from 1981–2018: A Trend-EOF Approach

Cerón, Wilmar L. | 2022

The Andes mountain range divides Colombia into various climatic regions over the country, as the Andean, Caribbean, Pacific, Amazon, and Orinoco regions. Given this scenario, knowing the current change in total precipitation and their extremes values are relevant. In this study, the main goal is to assess the spatio-temporal trends of heavy and intense rainfall at a seasonal scale during the last 38 years (1981-2018) using the trend empirical orthogonal function (TEOF). An increase in maximum precipitation during five consecutive days (RX5day), Simple daily intensity index (SDII), and the number of days with precipitation above 20 mm (R20mm) and 30 mm (R30mm) during December-February and March-May was observed in most of the Colombian territory, except for the Amazon region for RX5day. A decrease in total rainfall in June-August was observed in the Andean, the Caribbean, and southern Pacific regions, while, in the northern Pacific, it increased, consistent with the trend patterns of RX5day, SDII, and R20mm. During September-November, there was a reduction in rainfall in the Amazon region and the South Pacific, and an increase in RX5day, SDII, R20mm, and R30mm in the Andean, the Caribbean, and North Pacific regions. The TEOF showed more pronounced spatial trend patterns than those obtained with the traditional Mann-Kendall test. The findings offer a better understanding of the climate extremes impacts in tropical latitudes and help planners to implement measures against the future effects of climate change

Art workers in Colombia: Characteristics, symbolic consumption and social identity

Carrillo Barbosa, Ruby Lorena | 2022

Purpose: To explore the characteristics of Art Workers in Colombia, expressed in terms of lifestyles and consumption practices, as well as the relationship between symbolic consumption and the social identity of the group. Design/methodology/approach: For this quantitative study, the instrument called "Lifestyles and consumption practices", designed by the Konrand Lorentz University Foundation, was applied along with the incorporation of two new sections which evaluate symbolic consumption and social identity. The sample was intentional and represented 160 people, 80 of them corresponding to the Art Workers category and the other 80 to the Non-Art Workers category (mirror sample). Findings: It is observed that Art Workers in Colombia represent a social group with unique characteristics (lifestyles and consumption practices) looking for symbols in the products which allow them to relate to their counterparts in order to strengthen their sense of belonging to the social group. Originality/Value: This work contributes the literature of marketing with a new perspective of the Art Workers which separates them from their role as instruments of advertising strategies by linking them as consumers.

Breaking down barriers to surgical learning in times of COVID-19: an initiative of future surgeons

Ortega Sierra, Michael Gregorio | 2021

ESAT-6 and Ag85A Synthetic Peptides as Candidates for an Immunodiagnostic Test in Children with a Clinical Suspicion of Tuberculosis

Araujo, Zaida | 2021

Background. Tuberculosis (TB) is being underdetected in children as most are smear-negative. This work was aimed at evaluating ESAT-6 and Ag85A synthetic peptides’ serodiagnostic potential for diagnosing children having a clinical suspicion of TB. Methods. The study involved 438 children: 77 Creole nonindigenous (13 suspected of having TB and 64 healthy ones) and 361 Warao indigenous children (39 suspected of TB and 322 healthy children). The approach’s diagnostic information was compared using operational characteristics and receiver-operating characteristic (ROC) curves. Results. Ag85A P-29879 had 94.6% sensitivity (: 0.651 to 0.819 95% CI) in indigenous children. ESAT-6 P-12036 and P-12037 had 100% and 92.3% of sensitivity (: 0.929: 0.846 to 0.975 95% CI and 0.791: 63.9 to 98.7 95% CI, respectively) in Creole children. ESAT-6 peptides also allowed a differentiation between children with TB and healthy ones. Conclusions. Further validation of this approach could lead to developing a complementary tool for rapid TB diagnosis in children.

Machine learning models to select potential inhibitors of acetylcholinesterase activity from SistematX: a natural products database

Herrera-Acevedo, C. | 2021

Alzheimer's disease is the most common form of dementia, representing 60-70% of dementia cases. The enzyme acetylcholinesterase (AChE) cleaves the ester bonds in acetylcholine and plays an important role in the termination of acetylcholine activity at cholinergic synapses in various regions of the nervous system. The inhibition of acetylcholinesterase is frequently used to treat Alzheimer's disease. In this study, a merged BindingDB and ChEMBL dataset containing molecules with reported half-maximal inhibitory concentration (IC50) values for AChE (7032 molecules) was used to build machine learning classification models for selecting potential AChE inhibitors from the SistematX dataset (8593 secondary metabolites). A total of seven fivefold models with accuracy above 80% after cross-validation were obtained using three types of molecular descriptors (VolSurf, DRAGON 5.0, and bit-based fingerprints). A total of 521 secondary metabolites (6.1%) were classified as active in this stage. Subsequently, virtual screening was performed, and 25 secondary metabolites were identified as potential inhibitors of AChE. Separately, the crystal structure of AChE in complex with (-)-galantamine was used to perform molecular docking calculations with the entire SistematX dataset. Consensus analysis of both methodologies was performed. Only eight structures achieved combined probability values above 0.5. Finally, two sesquiterpene lactones, structures 15 and 24, were predicted to be able to cross the blood-brain barrier, which was confirmed in the VolSurf+ quantitative model, revealing these two structures as the most promising secondary metabolites for AChE inhibition among the 8593 molecules tested. A consensus analysis of classification models and molecular docking calculations identified four potential inhibitors of acetylcholinesterase from the SistematX dataset (8593 structures)