Molecular phylogenetics uncovers two new species in the genus Phyllobates (Anura, Dendrobatidae): the terrible frog gets two new sisters.

True poison-dart frogs (Phyllobates, Dendrobatidae) evolved the ability to secrete batrachotoxins, the most powerful alkaloids known to date. The genus comprises five species whose systematics, at first glance, appeared clear. The most derived clade would include two Colombian species (P.terribilis and P.bicolor) with the highest toxicity, the largest body size, and predominantly yellow body colouration. The other three species (P.aurotaenia, P.vittatus, and P.lugubris) are less toxic on average, have smaller size, and are predominantly black with bright dorsolateral stripes. Recent research has revealed the existence of two major lineages among the three Colombian species. The northern lineage appears to result from a complex evolutionary history, including perhaps introgression among yellow and black taxa. The southern lineage instead revealed the existence of new clades closely related to P.terribilis, black and yellow, that arguably deserve their recognition as new species. Here, available evidence is combined to support the erection of southern populations of P.aurotaenia as a new highly toxic species, sister to P.terribilis, and much closer to it than to any other yellow or black-bodied species, Phyllobatessamperi sp. nov. Their common ancestor is sister to an additional yellow species, which we also describe here as Phyllobatesbezosi sp. nov. Both new species can be externally diagnosed using colouration. Our previous and current analyses also suggest the existence of additional taxa and corroborate multiple transitions in colouration across these hypertoxic taxa.

ResumenLas verdaderas ranas de dardo venenoso (género Phyllobates) evolucionaron la capacidad de secretar batracotoxinas, los alcaloides más poderosos que se conocen hasta hoy. El género comprende cinco especies, cuya taxonomía parecía clara a primera vista. El clado más derivado incluye dos especies colombianas (P.terribilis and P.bicolor) con la mayor toxicidad, mayor tamaño y coloración predominantemente amarilla. Las otras tres especies (P.aurotaenia, P.vittatus and P.lugubris) son en general menos tóxicas, menores en tamaño y predominantemente negras con conspicuas manchas dorsolaterales.Una reciente investigación confirmó la existencia dos linajes mayores entre las tres especies colombianas. El del norte parece ser el producto de una historia evolutiva compleja, incluyendo quizás introgresión entre especies amarillas y negras. El del sur reveló en cambio la existencia de nuevos clados filogenéticamente cercanos a P.terribilis, uno negro y dos amarillos, que requieren reconocimiento formal como nuevas especies. Esta investigación combina la evidencia disponible para apoyar el reconocimiento de las poblaciones del sur de P.aurotaenia como una nueva especie negra, hermana de P.terribilis, y mucho más cercana a ella que a las otras especies negras o amarillas, Phyllobatessamperi sp. nov. Su ancestro común es a su vez el grupo hermano de una especie adicional, amarilla, que también describimos como Phyllobatesbezosi sp. nov. Las dos nuevas especies pueden ser externamente reconocidas por la coloración. Nuestros análisis previos y actuales también sugieren la existencia de otras especies no descritas y corroboran la existencia de múltiples transiciones de coloración en la evolución de las especies hipertóxicas.

Dissecting the complex genetic basis of pre- and post-harvest traits in Vitis vinifera L. using genome-wide association studies.

Addressing the pressing challenges in agriculture necessitates swift advancements in breeding programs, particularly for perennial crops like grapevines. Moving beyond the traditional biparental quantitative trait loci (QTL) mapping, we conducted a genome-wide association study (GWAS) encompassing 588 Vitis vinifera L. cultivars from a Chilean breeding program, spanning three seasons and testing 13 key yield-related traits. A strong candidate gene, Vitvi11g000454, located on chromosome 11 and related to plant response to biotic and abiotic stresses through jasmonic acid signaling, was associated with berry width and holds potential for enhancing berry size in grape breeding. We also mapped novel QTL associated with post-harvest traits across chromosomes 2, 4, 9, 11, 15, 18, and 19, broadening our grasp on the genetic intricacies dictating fruit post-harvest behavior, including decay, shriveling, and weight loss. Leveraging gene ontology annotations, we drew parallels between traits and scrutinized candidate genes, laying a robust groundwork for future trait-feature identification endeavors in plant breeding. We also highlighted the importance of carefully considering the choice of the response variable in GWAS analyses, as the use of best linear unbiased estimators (BLUEs) corrections in our study may have led to the suppression of some common QTL in grapevine traits. Our results underscore the imperative of pioneering non-destructive evaluation techniques for long-term conservation traits, offering grape breeders and cultivators insights to improve post-harvest table grape quality and minimize waste.

Transition metal (Ti, Cu, Zn, Pt) single-atom modified graphene/AS2 (A = Mo, W) van der Waals heterostructures for removing airborne pollutants.

Air pollution is a worldwide issue that affects human health and the environment. The scientific community tries to control it through different approaches, from experimental to theoretical assessments. Here, we perform DFT calculations to describe CO2, NO2, and SO2 detection on a single-atom (Ti, Cu, Zn, Pt) graphene supported on 2D molybdenum disulfide (MoS2) and tungsten disulfide (WS2). Transition metal single atoms on graphene improve the monolayer reactivity by generating an effective way to remove airborne pollutants. Results indicate that SO2 and NO2 chemically adsorb on all tested transition metals, whereas CO2 stands on top of the incorporated atoms through van der Waals interactions. Since strong Ti-O interactions appear, the Ti single-atom graphene/MoS2(WS2) systems efficiently remove CO2 from the environment. Compared to pristine graphene, our proposed heterostructures improve the SO2, NO2, and CO2 adsorption energies. The heterostructures' electronic properties change once the molecules interact with the transition metals, generating sensible and selective pollutant molecule detection and removal.

Advancing Alzheimer's Therapeutics: Exploring the Impact of Physical Exercise in Animal Models and Patients.

Alzheimer's disease (AD) is the main neurodegenerative disorder characterized by several pathophysiological features, including the misfolding of the tau protein and the amyloid beta (Aß) peptide, neuroinflammation, oxidative stress, synaptic dysfunction, metabolic alterations, and cognitive impairment. These mechanisms collectively contribute to neurodegeneration, necessitating the exploration of therapeutic approaches with multiple targets. Physical exercise has emerged as a promising non-pharmacological intervention for AD, with demonstrated effects on promoting neurogenesis, activating neurotrophic factors, reducing Aß aggregates, minimizing the formation of neurofibrillary tangles (NFTs), dampening inflammatory processes, mitigating oxidative stress, and improving the functionality of the neurovascular unit (NVU). Overall, the neuroprotective effects of exercise are not singular, but are multi-targets. Numerous studies have investigated physical exercise's potential in both AD patients and animal models, employing various exercise protocols to elucidate the underlying neurobiological mechanisms and effects. The objective of this review is to analyze the neurological therapeutic effects of these exercise protocols in animal models and compare them with studies conducted in AD patients. By translating findings from different approaches, this review aims to identify opportune, specific, and personalized therapeutic windows, thus advancing research on the use of physical exercise with AD patients.

Escala de Resistencia a la Presión de Pares para el Consumo de Cigarro Convencional en estudiantes universitarios: adaptación y validación / Resistance to Peer Pressure for Cigarette Smoking in University Students: Scale Adaptation and Validation / Escala de resistência à pressão dos pares para o consumo de cigarros em universitários: adaptação e validação

Introducción: la influencia o presión de pares que fuman es uno de los principales factores por los que los estudiantes universitarios inician el consumo del cigarro convencional; sin embargo, no se ha encontrado un instrumento que evalúe este fenómeno. Por lo tanto, el objetivo fue adaptar y validar la Escala de Resistencia a la Presión de Pares para el Consumo de Cigarro Convencional. Materiales y métodos: participaron 237 estudiantes universitarios del estado de Nuevo León (México), de 18 a 24 años. Se realizó análisis factorial exploratorio, análisis de confiabilidad, correlación de Spearman y prueba de Kruskal-Wallis. Resultados: el 63.3 % de los estudiantes fueron mujeres y la media de edad fue de 19.66 años. Se identificaron dos factores con un total de 13 ítems. Se obtuvo un alfa de Cronbach de 0.81. Se encontraron diferencias estadísticamente significativas entre los distintos tipos de consumidores de cigarro convencional y los puntajes de la escala de resistencia a la presión de pares (H[4] = 23.85; p < 0.001). Conclusiones: la nueva versión de la Escala de Resistencia a la Presión de Pares para el Consumo de Cigarro Convencional evidenció adecuadas propiedades psicométricas para evaluar la presión que ejercen los pares en estudiantes universitarios para el consumo de cigarro convencional

Introduction: Influence or peer pressure is one of the leading factors in developing cigarette smoking habits in university students; however, no effective strategy to assess this phenomenon has been developed yet. This study aimed to adapt and validate the peer pressure resistance scale to conventional cigarette consumption. Materials and methods: A total of 237 university students from the Nuevo León State (Mexico), aged 18­24 years, were enrolled. Exploratory factor and reliability analyses, the Spearman correlation, and the Kruskal­Wallis test were performed. Results: 63.3% of the students were women, and the mean age was 19.66 years. The exploratory analysis extracted two factors with a total of 13 items. A Cronbach's Alpha of 0.81 was found. Statistically significant differences were found between the different types of conventional cigarette users and peer pressure resistance scale scores [H(4) = 23.85; p < .001] were found. Conclusions: The peer pressure resistance scale showed appropriate psychometric properties for assessing the peer pressure to smoke conventional cigarettes in university students.

Introdução: a influência ou pressão dos pares que fumam é um dos principais fatores que levam os universitários a começarem a fumar cigarros convencionais, porém não foi encontrado nenhum instrumento para avaliar esse fenômeno. Portanto, o objetivo do trabalho foi adaptar e validar a escala de resistência à pressão dos pares para o consumo de cigarro convencional. Materiais e métodos: participaram 237 estudantes universitários do estado de Nuevo León, México, de 18 a 24 anos. Foram realizadas análise fatorial exploratória, análise de confiabilidade, correlação de Spearman e teste de Kruskal-Wallis. Resultados: 63,3% dos alunos eram mulheres e a média de idade foi de 19,66 anos. Dois fatores foram identificados com um total de 13 itens. Obteve-se um alfa de Cronbach de 0,81. Diferenças estatisticamente significativas foram encontradas entre os diferentes tipos de usuários de cigarros convencionais e as pontuações na escala de resistência à pressão dos pares (H(4) = 23,85; p < 0,001). Conclusões: a nova versão da escala de resistência à pressão dos pares para o consumo de cigarros convencionais apresentou propriedades psicométricas adequadas para avaliar a pressão exercida pelos pares sobre os universitários para o consumo de cigarros convencionais

Effects of Voluntary Physical Exercise on the Neurovascular Unit in a Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide. Histopathologically, AD presents two pathognomonic hallmarks: (1) neurofibrillary tangles, characterized by intracellular deposits of hyperphosphorylated tau protein, and (2) extracellular amyloid deposits (amyloid plaques) in the brain vasculature (cerebral amyloid angiopathy; CAA). It has been proposed that vascular amyloid deposits could trigger neurovascular unit (NVU) dysfunction in AD. The NVU is composed primarily of astrocytic feet, endothelial cells, pericytes, and basement membrane. Although physical exercise is hypothesized to have beneficial effects against AD, it is unknown whether its positive effects extend to ameliorating CAA and improving the physiology of the NVU. We used the triple transgenic animal model for AD (3xTg-AD) at 13 months old and analyzed through behavioral and histological assays, the effect of voluntary physical exercise on cognitive functions, amyloid angiopathy, and the NVU. Our results show that 3xTg-AD mice develop vascular amyloid deposits which correlate with cognitive deficits and NVU alteration. Interestingly, the physical exercise regimen decreases amyloid angiopathy and correlates with an improvement in cognitive function as well as in the underlying integrity of the NVU components. Physical exercise could represent a key therapeutic approach in cerebral amyloid angiopathy and NVU stability in AD patients.

Ab initio study of the adsorption of SO2 on single-atom Cu-decorated ZnO(0001) surface.

CONTEXT: The World Health Organization has cataloged sulfur dioxide (SO2) as harmful for the human health and the environment. It also contributes to generate acid rain, which affects the ecosystems. To reduce its negative effects, new strategies to control the emissions are required. New and engineered materials are investigated to detect, capture, and eradicate toxic gases from the environment. Zinc oxide is considered a promising candidate. Here, we investigate the Cu-decorated ZnO(0001) surfaces as a single-atom catalyst (SAC) to reduce SO2 by first-principles calculations. We propose a two-step reduction mechanism. First, one of the S-O bonds is broken on the pristine surface, with a calculated activation energy of 14.76 kcal/mol, 1.84 kcal/mol larger than the one obtained in the Cu SAC. In the second step, the SO reduction is viable only for Cu SAC, with calculated activation energy of 29.28 kcal/mol. Our results point that Cu SAC improves the SO2 reduction, pointing it as a potentially efficient device to eradicate such harmful pollutant from the environment. METHODS: The calculations were performed using the density functional theory, as implemented in quantum ESPRESSO package. The exchange-correlation energy was calculated within the generalized gradient approximation with the Perdew-Burke-Ernzerhof parameterization. Van der Waals dispersion-corrected interactions were considered. Spin-polarization was considered for studying dangling bonds in transition states. The minimum energy pathways were calculated by using the climbing image nudged elastic band.

Psychosocial Risks and Mental Disorders among Mexican Oil Workers / Riesgos psicosociales y trastornos mentales en trabajadores petroleros mexicanos / Riscos psicossociais e transtornos mentais em trabalhadores petrolíferos mexicanos

The psychosocial risks faced by workers can influence their health as well as job performance and satisfaction. However, this phenomenon among Mexican workers in the oil industry has not been well studied. The purpose of this study was to analyze the association of stress and job-related burnout with mental disorders among oil workers in the southeastern region of Mexico. Materials and methods: This cross-sectional and analytical study included 501 workers from the onshore oil industry in the southeastern region of Mexico. The Work Burnout Inventory, the Symptoms of Stress Inventory, and the Goldberg General Health Questionnaire (ghq 28) were applied between October and November, 2016. Chi-square test was used to analyze the relationship between variables and the odds ratio was determined to establish the level of risk for mental disorders. Results: Moderate levels of stress (21.4l %), efficacy (41.5 %), cynicism (30.6 %), and exhaustion (39.7 %) were observed. Mental disorders were noted in 11.8 % of workers. Stress and burnout were associated with mental disorders (p < 0.05). Finally, workers who experienced stress and job burnout were more likely to have mental disorders (or = 12.96; 95 % ci [7.03­23.94]; p = 0.00). Conclusions:Stress and job burnout are risk factors for mental disorders among Mexican oil workers.

los riesgos psicosociales en los trabajadores tienen influencia en la salud, rendimiento del trabajo y satisfacción laboral; sin embargo, poco se ha estudiado este fenómeno en los trabajadores mexicanos de la industria petrolera. El objetivo fue analizar la asociación entre estrés y desgaste laboral y trastornos en los trabajadores de la industria petrolera terrestre de la región sureste de México. Materiales y métodos: diseño transversal y analítico. La muestra estuvo integrada por 501 trabajadores. Los instrumentos utilizados fueron el Inventario de Desgaste Laboral, el Inventario de Síntomas de Estrés y el Cuestionario de Salud General de Goldberg (ghq 28). Se aplicaron los instrumentos entre octu-bre y noviembre de 2016. Se utilizó la prueba de chi cuadrado para analizar la relación entre las variables, y se determinaron odds ratio para establecer el nivel de riesgo a trastornos mentales. Resultados: se encontraron niveles moderados de estrés (21.4l %), eficacia (41.5 %), cinismo (30.6 %) y agotamiento (39.7 %). Se encontró presencia de trastornos mentales en el 11.8 % de los trabajadores. El estrés y las dimensiones del desgaste laboral se asociaron con los trastornos mentales (p < 0.05). Finalmente, los tra-bajadores que presentaron estrés y desgaste laboral tuvieron mayor probabilidad de sufrir trastornos mentales (or= 12.96; ic 95 % [7.03-23.94]; p = 0.00). Conclusiones: el estrés y el desgaste laboral representan factores de riesgo para presentar trastornos mentales en los trabajadores petroleros mexicanos.

os riscos psicossociais nos trabalhadores influenciam a saúde, o desempenho no trabalho e a satisfação no trabalho, no entanto, esse fenômeno tem sido pouco estudado em trabalhadores mexi-canos da indústria petrolífera. O objetivo do estudo foi analisar a associação do estresse e desgaste no trabalho com transtornos em trabalhadores da indústria petrolífera terrestre da região sudeste do México. Materiais e métodos: desenho transversal e analítico. A amostra foi composta por 501 trabalha-dores. Os instrumentos utilizados foram o Inventário de Desgaste Laboral, o Inventário de Sintomas de Estresse e o Questionário de Saúde Geral de Goldberg (ghq 28). Os instrumentos foram aplicados entre outubro e novembro de 2016. O teste qui-quadrado foi utilizado para analisar a relação entre as variáveis e o odds ratio foi determinado para estabelecer o nível de risco para transtornos mentais. Resultados: foram encontrados níveis moderados de estresse (21,4l %), eficácia (41,5 %), cinismo (30,6 %) e exaustão (39,7 %). A presença de transtornos mentais foi encontrada em 11,8 % dos trabalhadores. O estresse e as dimensões de desgaste laboral foram associadas aos transtornos mentais (p < 0,05). Por fim, os trabalhadores que apresentavam estresse e desgaste laboral apresentaram maior probabilidade de apresentar transtornos mentais (or = 12,96; ic 95 % [7,03-23,94]; p = 0,00). Conclusões: o estresse e desgaste laboral representam fatores de risco para o desenvolvimento de transtornos mentais em trabalhadores petrolíferos mexicanos.

Condiciones de trabajo percibidas por enfermeras migrantes mexicanas en Alemania / Occupational Conditions Perceived by Mexican Migrant Nurses in Germany

Introducción: Se espera que la migración de profesionales de enfermería mexicanos aumente en los próximos años debido a la escasez de enfermeras en todo el mundo. Es urgente estudiar las condiciones de trabajo de las enfermeras mexicanas en los países de acogida desde una perspectiva transcultural. Objetivo: Examinar las percepciones laborales de las enfermeras mexicanas que ejercen en un entorno clínico en Alemania desde una perspectiva transcultural. Métodos: Se realizó un estudio etnográfico focalizado entre noviembre de 2020 y mayo de 2021. La muestra (n = 11) involucró a profesionales de enfermería de México que trabajan en un entorno clínico en Alemania. Los datos se recogieron mediante entrevistas semiestructuradas a través de la plataforma digital Zoom. Las entrevistas fueron grabadas en audio previo consentimiento informado. Se utilizó un análisis temático para analizar los datos; QUIRKOS, un software de análisis de datos cualitativos ayudó en el proceso. Resultados: Se identificaron tres temas: las condiciones estructurales de trabajo, que describen las características del trabajo que influyen en la realización del cuidado transcultural de enfermería; la diversidad cultural de los cuidados, que describe la variabilidad del significado de los cuidados de enfermería; y la práctica transcultural, que describe las percepciones culturales de las enfermeras en relación con los cuidados que prestan en Alemania. Conclusiones: Las condiciones estructurales de trabajo y la diversidad cultural de los cuidados favorecen o impiden la calidad de los cuidados que prestan las enfermeras mexicanas en Alemania. Los hallazgos sugieren la necesidad de abogar por políticas que mejoren las condiciones de trabajo de las enfermeras en México y en Alemania(AU)

Introduction: Migration of Mexican nursing professionals is expected to increase in the coming years, due to the shortage of nurses worldwide. There is an urgent need to study the occupational conditions of Mexican nurses in host countries from a cross-cultural perspective. Objective: To examine the occupational perceptions of Mexican nurses practicing in a clinical setting in Germany, from a cross-cultural perspective. Methods: A focused ethnographic study was conducted between November 2020 and May 2021. The sample (n=11) involved nursing professionals from Mexico working in a clinical setting in Germany. The data were collected through semistructured interviews via the digital platform Zoom. The interviews were audio-recorded with prior informed consent. A thematic analysis was used to analyze the data; Quirkos, a qualitative data analysis software, was used in the process. Results: Three themes were identified: structural occupational conditions, describing the occupational characteristics that influence the performance of transcultural nursing care; cultural diversity of care, describing variability in the meaning of nursing care; and transcultural practice, describing nurses' cultural perceptions of the care that they provide in Germany. Conclusions: Structural occupational conditions and cultural diversity of care favor or impede the quality of care provided by Mexican nurses in Germany. The findings suggest the need to advocate for policies that improve the occupational conditions of nurses in Mexico and Germany(AU)

Hyperphosphorylated Tau Relates to Improved Cognitive Performance and Reduced Hippocampal Excitability in the Young rTg4510 Mouse Model of Tauopathy.

BACKGROUND: Tau hyperphosphorylation at several sites, including those close to its microtubule domain (MD), is considered a key pathogenic event in the development of tauopathies. Nevertheless, we recently demonstrated that at the very early disease stage, tau phosphorylation (pTau) at MD sites promotes neuroprotection by preventing seizure-like activity. OBJECTIVE: To further support the notion that very early pTau is not detrimental, the present work evaluated the young rTg4510 mouse model of tauopathy as a case study. Thus, in mice at one month of age (PN30-35), we studied the increase of pTau within the hippocampal area as well as hippocampal and locomotor function. METHODS: We used immunohistochemistry, T-maze, nesting test, novel object recognition test, open field arena, and electrophysiology. RESULTS: Our results showed that the very young rTg4510 mouse model has no detectable changes in hippocampal dependent tasks, such as spontaneous alternation and nesting, or in locomotor activity. However, at this very early stage the hippocampal neurons from PN30-35 rTg4510 mice accumulate pTau protein and exhibit changes in hippocampal oscillatory activity. Moreover, we found a significant reduction in the somatic area of pTau positive pyramidal and granule neurons in the young rTg4510 mice. Despite this, improved memory and increased number of dendrites per cell in granule neurons was found. CONCLUSION: Altogether, this study provides new insights into the early pathogenesis of tauopathies and provides further evidence that pTau remodels hippocampal function and morphology.

Ten Approaches That Improve Immunostaining: A Review of the Latest Advances for the Optimization of Immunofluorescence.

Immunostaining has emerged as one of the most common and valuable techniques that allow the localization of proteins at a quantitative level within cells and tissues using antibodies coupled to enzymes, fluorochromes, or colloidal nanogold particles. The application of fluorochromes during immunolabeling is referred to as immunofluorescence, a method coupled to widefield or confocal microscopy and extensively applied in basic research and clinical diagnosis. Notwithstanding, there are still disadvantages associated with the application of this technique due to technical challenges in the process, such as sample fixation, permeabilization, antibody incubation times, and fluid exchange, etc. These disadvantages call for continuous updates and improvements to the protocols extensively described in the literature. This review contributes to protocol optimization, outlining 10 current methods for improving sample processing in different stages of immunofluorescence, including a section with further recommendations. Additionally, we have extended our own antibody signal enhancer method, which was reported to significantly increase antibody signals and is useful for cervical cancer detection, to improve the signals of fluorochrome-conjugated staining reagents in fibrous tissues. In summary, this review is a valuable tool for experienced researchers and beginners when planning or troubleshooting the immunofluorescence assay.

A new species of Andean golden poison frog (Andinobates, Dendrobatidae) from the Eastern Andes of Colombia.

A new species of Andinobates (Dendrobatidae) is described from the East Andes of Colombia, just 37 km away from the Colombian capital, Bogot. Andinobates supata sp. nov., represents the second known species of yellow Andinobates, and can be distinguished from the other, Andinobates tolimensis, by an unique combination of ventral and dorsal color patterns. Our phylogenetic analyses, based on ≈ 1120 bp from two mitochondrial markers (16S rRNA and cytochrome b) showed that this new taxon is sister to a clade formed by A. cassidyhornae, A. bombetes, A. opisthomelas, A. tolimensis and A. virolinensis. The new species appears to be restricted to a handful of small forest fragments (10 ha) distributed in no more than 5 km2, between 18002000 m elevation, where the human activity is high. In addition, more than 90% of the original forest has been logged at the type locality, and its watersheds receive considerable agrochemical discharges. Altogether, the evidence suggests that this new species should be listed as Critically Endangered and should receive immediate attention regarding basic research and urgent conservation measures.

Protective effects of intracerebroventricular adiponectin against olfactory impairments in an amyloid ß1-42 rat model.

BACKGROUND: Alzheimer's disease (AD) is characterized by cognitive impairment that eventually develops into dementia. Amyloid-beta (Aß) accumulation is a widely described hallmark in AD, and has been reported to cause olfactory dysfunction, a condition considered an early marker of the disease associated with injuries in the olfactory bulb (OB), the hippocampus (HIPP) and other odor-related cortexes. Adiponectin (APN) is an adipokine with neuroprotective effects. Studies have demonstrated that APN administration decreases Aß neurotoxicity and Tau hyperphosphorylation in the HIPP, reducing cognitive impairment. However, there are no studies regarding the neuroprotective effects of APN in the olfactory dysfunction observed in the Aß rat model. The aim of the present study is to determine whether the intracerebroventricular (i.c.v) administration of APN prevents the early olfactory dysfunction in an i.c.v Amyloid-beta1-42 (Aß1-42) rat model. Hence, we evaluated olfactory function by using a battery of olfactory tests aimed to assess olfactory memory, discrimination and detection in the Aß rat model treated with APN. In addition, we determined the number of cells expressing the neuronal nuclei (NeuN), as well as the number of microglial cells by using the ionized calcium-binding adapter molecule 1 (Iba-1) marker in the OB and, CA1, CA3, hilus and dentate gyrus (DG) in the HIPP. Finally, we determined Arginase-1 expression in both nuclei through Western blot. RESULTS: We observed that the i.c.v injection of Aß decreased olfactory function, which was prevented by the i.c.v administration of APN. In accordance with the olfactory impairment observed in i.c.v Aß-treated rats, we observed a decrease in NeuN expressing cells in the glomerular layer of the OB, which was also prevented with the i.c.v APN. Furthermore, we observed an increase of Iba-1 cells in CA1, and DG in the HIPP of the Aß rats, which was prevented by the APN treatment. CONCLUSION: The present study describes the olfactory impairment of Aß treated rats and evidences the protective role that APN plays in the brain, by preventing the olfactory impairment induced by Aß1-42. These results may lead to APN-based pharmacological therapies aimed to ameliorate AD neurotoxic effects.

Enfermeros mexicanos en Alemania en tiempos de Covid-19.

Señor editor: La emigración de enfermeros mexicanos hacia el extranjero es un tema que cobra relevancia durante la pandemia por Covid-19, principalmente por la necesidad de contar con profesionales calificados que hagan frente a esta situación de emergencia sanitaria. Pero ¿por qué los enfermeros están emigrando cuando México también tiene escasez de estos profesionales?..

A new naphthalene derivative with anti-amyloidogenic activity as potential therapeutic agent for Alzheimer's disease.

The aggregation of ß-amyloid peptides is associated to neurodegeneration in Alzheimer's disease (AD) patients. Consequently, the inhibition of both oligomerization and fibrillation of ß-amyloid peptides is considered a plausible therapeutic approach for AD. Herein, the synthesis of new naphthalene derivatives and their evaluation as anti-ß-amyloidogenic agents are presented. Molecular dynamic simulations predicted the formation of thermodynamically stable complexes between the compounds, the Aß1-42 peptide and fibrils. In human microglia cells, these compounds inhibited the aggregation of Aß1-42 peptide. The lead compound 8 showed a high affinity to amyloid plaques in mice brain ex vivo assays and an adequate log Poct/PBS value. Compound 8 also improved the cognitive function and decreased hippocampal ß-amyloid burden in the brain of 3xTg-AD female mice. Altogether, our results suggest that 8 could be a novel therapeutic agent for AD.

Morris water maze overtraining increases the density of thorny excrescences in the basal dendrites of CA3 pyramidal neurons.

The hippocampus plays a fundamental role in spatial learning and memory. Dentate gyrus (DG) granular neurons project mainly to proximal apical dendrites of neurons in the CA3 stratum lucidum and also, to some extent, to the basal dendrites of CA3 pyramidal cells in the stratum oriens. The terminal specializations of DG neurons are the mossy fibers (MF), and these huge axon terminals show expansion in the CA3 stratum oriens after the animals undergo overtraining in the Morris Water Maze task (MWM). However, to our knowledge there are no reports regarding the possible changes in density of post-synaptic targets of these terminals in the basal dendrites of CA3 neurons after overtraining in the MWM. The purpose of this work was to study the density of thorny excrescences (TE) and other dendritic spine types (stubby, thin, and mushroom) in the CA3 stratum oriens in animals overtrained in the MWM for three consecutive days and in animals trained for only one day. Seven days after MWM training, the animals were sacrificed, and their brains removed and processed for rapid Golgi staining to visualize the different types of dendritic protrusions. Our results revealed that the relative quantity of stubby, thin, and mushroom dendritic spines did not change, regardless of amount of training. However, a significant increase in the density of TE was detected in the overtrained animals. These results strongly suggest that spatial water maze overtraining induces an increased density of MF-TE connections, which might be functionally relevant for long-term spatial memory formation.