Knockdown of tgfb1a partially improves ALS phenotype in a transient zebrafish model.

Amyotrophic lateral sclerosis (ALS) corresponds to a neurodegenerative disorder marked by the progressive degeneration of both upper and lower motor neurons located in the brain, brainstem, and spinal cord. ALS can be broadly categorized into two main types: sporadic ALS (sALS), which constitutes approximately 90% of all cases, and familial ALS (fALS), which represents the remaining 10% of cases. Transforming growth factor type-ß (TGF-ß) is a cytokine involved in various cellular processes and pathological contexts, including inflammation and fibrosis. Elevated levels of TGF-ß have been observed in the plasma and cerebrospinal fluid (CSF) of both ALS patients and mouse models. In this perspective, we explore the impact of the TGF-ß signaling pathway using a transient zebrafish model for ALS. Our findings reveal that the knockdown of tgfb1a lead to a partial prevention of motor axon abnormalities and locomotor deficits in a transient ALS zebrafish model at 48 h post-fertilization (hpf). In this context, we delve into the proposed distinct roles of TGF-ß in the progression of ALS. Indeed, some evidence suggests a dual role for TGF-ß in ALS progression. Initially, it seems to exert a neuroprotective effect in the early stages, but paradoxically, it may contribute to disease progression in later stages. Consequently, we suggest that the TGF-ß signaling pathway emerges as an attractive therapeutic target for treating ALS. Nevertheless, further research is crucial to comprehensively understand the nuanced role of TGF-ß in the pathological context.

Modeling Spinal Muscular Atrophy in Zebrafish: Current Advances and Future Perspectives.

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by degeneration of lower motor neurons (LMNs), causing muscle weakness, atrophy, and paralysis. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene and can be classified into four subgroups, depending on its severity. Even though the genetic component of SMA is well known, the precise mechanisms underlying its pathophysiology remain elusive. Thus far, there are three FDA-approved drugs for treating SMA. While these treatments have shown promising results, their costs are extremely high and unaffordable for most patients. Thus, more efforts are needed in order to identify novel therapeutic targets. In this context, zebrafish (Danio rerio) stands out as an ideal animal model for investigating neurodegenerative diseases like SMA. Its well-defined motor neuron circuits and straightforward neuromuscular structure offer distinct advantages. The zebrafish's suitability arises from its low-cost genetic manipulation and optical transparency exhibited during larval stages, which facilitates in vivo microscopy. This review explores advancements in SMA research over the past two decades, beginning with the creation of the first zebrafish model. Our review focuses on the findings using different SMA zebrafish models generated to date, including potential therapeutic targets such as U snRNPs, Etv5b, PLS3, CORO1C, Pgrn, Cpg15, Uba1, Necdin, and Pgk1, among others. Lastly, we conclude our review by emphasizing the future perspectives in the field, namely exploiting zebrafish capacity for high-throughput screening. Zebrafish, with its unique attributes, proves to be an ideal model for studying motor neuron diseases and unraveling the complexity of neuromuscular defects.

Hox genes control homocercal caudal fin development and evolution.

Ancient bony fishes had heterocercal tails, like modern sharks and sturgeons, with asymmetric caudal fins and a vertebral column extending into an elongated upper lobe. Teleost fishes, in contrast, developed a homocercal tail characterized by two separate equal-sized fin lobes and the body axis not extending into the caudal fin. A similar heterocercal-to-homocercal transition occurs during teleost ontogeny, although the underlying genetic and developmental mechanisms for either transition remain unresolved. Here, we investigated the role of hox13 genes in caudal fin formation as these genes control posterior identity in animals. Analysis of expression profiles of zebrafish hox13 paralogs and phenotypes of CRISPR/Cas9-induced mutants showed that double hoxb13a and hoxc13a mutants fail to form a caudal fin. Furthermore, single mutants display heterocercal-like morphologies not seen since Mesozoic fossil teleosteomorphs. Relaxation of functional constraints after the teleost genome duplication may have allowed hox13 duplicates to neo- or subfunctionalize, ultimately contributing to the evolution of a homocercal tail in teleost fishes.

Diversity, Taxonomic Novelty, and Encoded Functions of Salar de Ascotán Microbiota, as Revealed by Metagenome-Assembled Genomes.

Salar de Ascotán is a high-altitude arsenic-rich salt flat exposed to high ultraviolet radiation in the Atacama Desert, Chile. It hosts unique endemic flora and fauna and is an essential habitat for migratory birds, making it an important site for conservation and protection. However, there is limited information on the resident microbiota's diversity, genomic features, metabolic potential, and molecular mechanisms that enable it to thrive in this extreme environment. We used long- and short-read metagenomics to investigate the microbial communities in Ascotán's water, sediment, and soil. Bacteria predominated, mainly Pseudomonadota, Acidobacteriota, and Bacteroidota, with a remarkable diversity of archaea in the soil. Following hybrid assembly, we recovered high-quality bacterial (101) and archaeal (6) metagenome-assembled genomes (MAGs), including representatives of two putative novel families of Patescibacteria and Pseudomonadota and two novel orders from the archaeal classes Halobacteriota and Thermoplasmata. We found different metabolic capabilities across distinct lineages and a widespread presence of genes related to stress response, DNA repair, and resistance to arsenic and other metals. These results highlight the remarkable diversity and taxonomic novelty of the Salar de Ascotán microbiota and its rich functional repertoire, making it able to resist different harsh conditions. The highly complete MAGs described here could serve future studies and bioprospection efforts focused on salt flat extremophiles, and contribute to enriching databases with microbial genome data from underrepresented regions of our planet.

Antimicrobial resistance, pathogenic potential, and genomic features of carbapenem-resistant Klebsiella pneumoniae isolated in Chile: high-risk ST25 clones and novel mobile elements.

Multidrug- and carbapenem-resistant Klebsiella pneumoniae (CR-Kp) are critical threats to global health and key traffickers of resistance genes to other pathogens. Despite the sustained increase in CR-Kp infections in Chile, few strains have been described at the genomic level, lacking details of their resistance and virulence determinants and the mobile elements mediating their dissemination. In this work, we studied the antimicrobial susceptibility and performed a comparative genomic analysis of 10 CR-Kp isolates from the Chilean surveillance of carbapenem-resistant Enterobacteriaceae. High resistance was observed among the isolates (five ST25, three ST11, one ST45, and one ST505), which harbored 44 plasmids, most carrying genes for conjugation and resistance to several antibiotics and biocides. Ten plasmids encoding carbapenemases were characterized, including novel plasmids or variants with additional resistance genes, a novel genetic environment for blaKPC-2, and plasmids widely disseminated in South America. ST25 K2 isolates belonging to CG10224, a clone traced back to 2012 in Chile, which recently acquired blaNDM-1, blaNDM-7, or blaKPC-2 plasmids stood out as high-risk clones. Moreover, this corresponds to the first report of ST25 and ST45 Kp producing NDM-7 in South America and ST505 CR-Kp producing both NDM-7 and KPC-2 worldwide. Also, we characterized a variety of genomic islands carrying virulence and fitness factors. These results provide baseline knowledge for a detailed understanding of molecular and genetic determinants behind antibiotic resistance and virulence of CR-Kp in Chile and South America. IMPORTANCE In the ongoing antimicrobial resistance crisis, carbapenem-resistant strains of Klebsiella pneumoniae are critical threats to public health. Besides globally disseminated clones, the burden of local problem clones remains substantial. Although genomic analysis is a powerful tool for improving pathogen and antimicrobial resistance surveillance, it is still restricted in low- to middle-income countries, including Chile, causing them to be underrepresented in genomic databases and epidemiology surveys. This study provided the first 10 complete genomes of the Chilean surveillance for carbapenem-resistant K. pneumoniae in healthcare settings, unveiling their resistance and virulence determinants and the mobile genetic elements mediating their dissemination, placed in the South American and global K. pneumoniae epidemiological context. We found ST25 with K2 capsule as an emerging high-risk clone, along with other lineages producing two carbapenemases and several other resistance and virulence genes encoded in novel plasmids and genomic islands.

Drosophila DAxud1 Has a Repressive Transcription Activity on Hsp70 and Other Heat Shock Genes.

Drosophila melanogaster DAxud1 is a transcription factor that belongs to the Cysteine Serine Rich Nuclear Protein (CSRNP) family, conserved in metazoans, with a transcriptional transactivation activity. According to previous studies, this protein promotes apoptosis and Wnt signaling-mediated neural crest differentiation in vertebrates. However, no analysis has been conducted to determine what other genes it might control, especially in connection with cell survival and apoptosis. To partly answer this question, this work analyzes the role of Drosophila DAxud1 using Targeted-DamID-seq (TaDa-seq), which allows whole genome screening to determine in which regions it is most frequently found. This analysis confirmed the presence of DAxud1 in groups of pro-apoptotic and Wnt pathway genes, as previously described; furthermore, stress resistance genes that coding heat shock protein (HSP) family genes were found as hsp70, hsp67, and hsp26. The enrichment of DAxud1 also identified a DNA-binding motif (AYATACATAYATA) that is frequently found in the promoters of these genes. Surprisingly, the following analyses demonstrated that DAxud1 exerts a repressive role on these genes, which are necessary for cell survival. This is coupled with the pro-apoptotic and cell cycle arrest roles of DAxud1, in which repression of hsp70 complements the maintenance of tissue homeostasis through cell survival modulation.

Apuntes para una historia de la radiología en Matanzas: continuadores y desarrollo en algunas localidades

Introducción: la radiología, incluyendo las nuevas formas de obtener imágenes médicas para diagnóstico y guía de procederes, es una de las especialidades que más desarrollo científico-tecnológico ha experimentado a través de la historia de las ciencias médicas. En Matanzas, fue instaurada en la segunda década del siglo XX por un grupo de figuras e instituciones precursoras, a las que fueron sumándose otras que han mantenido la disciplina hasta el presente. Objetivo: rescatar elementos de la historia de la radiología en la provincia de Matanzas, relacionados con quienes continuaron la obra de los precursores. Materiales y métodos: se utilizaron métodos propios de la investigación histórica como el analítico-sintético y el deductivo-inductivo, al igual que los submétodos cronológico y geográfico. Resultados: se presentaron trece fichas y veintitrés anotaciones que constituyen una caracterización sintética del objeto de estudio. Conclusiones: en la historia de la radiología en Matanzas, destacan como continuadores, en la etapa inmediata posterior a la de los precursores, nombres como los de los doctores Mario Muñoz Monroy y Manuel García Suárez. El primero, sobresale por su dimensión como mártir, y el segundo, aunque se opuso también a dictaduras, por su proyección científico-pedagógica. La especialidad alcanzó su verdadero encargo social en la década de 1960, y ha experimentado un progreso sostenido, cuya magnitud ha dependido de limitaciones externas e internas.

Introduction: radiology, including the new ways of obtaining medical images for prognosis and procedures guidance, is one of the specialties that more scientific-technological development has experienced throughout the history of the medical sciences. It was established in Matanzas in the second decade of the 20th century by a group of precursor figures and institutions, to which were added others that have maintained the discipline up to these days. Objective: to rescue elements of the history of radiology in the province of Matanzas, related to those who continued the work of the precursors. Materials and methods: typical methods of the historical research such as analytic-synthetic and deductive-inductive were used, and well as chronological and geographic sub-methods. Results: thirteen records and twenty-three annotations were presented that constitute a synthetic characterization of the object of study. Conclusions: in the history of radiology in Matanzas, names such as those of doctors Mario Munoz Monroy and Manuel Garcia Suarez stand out in the immediate stage after precursors; the first, because of his dimension as a martyr, and the second, although he also opposed dictatorships, because of his scientific-pedagogical projection. The specialty reached its true social charge in the 1960's, and has experienced a sustained progress, the magnitude of which has depended on external and internal limitations.

DNA sequencing in the classroom: complete genome sequence of two earwig (Dermaptera; Insecta) species.

BACKGROUND: Despite representing the largest fraction of animal life, the number of insect species whose genome has been sequenced is barely in the hundreds. The order Dermaptera (the earwigs) suffers from a lack of genomic information despite its unique position as one of the basally derived insect groups and its importance in agroecosystems. As part of a national educational and outreach program in genomics, a plan was formulated to engage the participation of high school students in a genome sequencing project. Students from twelve schools across Chile were instructed to capture earwig specimens in their geographical area, to identify them and to provide material for genome sequencing to be carried out by themselves in their schools. RESULTS: The school students collected specimens from two cosmopolitan earwig species: Euborellia annulipes (Fam. Anisolabididae) and Forficula auricularia (Fam. Forficulidae). Genomic DNA was extracted and, with the help of scientific teams that traveled to the schools, was sequenced using nanopore sequencers. The sequence data obtained for both species was assembled and annotated. We obtained genome sizes of 1.18 Gb (F. auricularia) and 0.94 Gb (E. annulipes) with the number of predicted protein coding genes being 31,800 and 40,000, respectively. Our analysis showed that we were able to capture a high percentage (≥ 93%) of conserved proteins indicating genomes that are useful for comparative and functional analysis. We were also able to characterize structural elements such as repetitive sequences and non-coding RNA genes. Finally, functional categories of genes that are overrepresented in each species suggest important differences in the process underlying the formation of germ cells, and modes of reproduction between them, features that are one of the distinguishing biological properties that characterize these two distant families of Dermaptera. CONCLUSIONS: This work represents an unprecedented instance where the scientific and lay community have come together to collaborate in a genome sequencing project. The versatility and accessibility of nanopore sequencers was key to the success of the initiative. We were able to obtain full genome sequences of two important and widely distributed species of insects which had not been analyzed at this level previously. The data made available by the project should illuminate future studies on the Dermaptera.

DNA sequencing in the classroom: complete genome sequence of two earwig (Dermaptera; Insecta) species

BACKGROUND: Despite representing the largest fraction of animal life, the number of insect species whose genome has been sequenced is barely in the hundreds. The order Dermaptera (the earwigs) suffers from a lack of genomic information despite its unique position as one of the basally derived insect groups and its importance in agroecosystems. As part of a national educational and outreach program in genomics, a plan was formulated to engage the participation of high school students in a genome sequencing project. Students from twelve schools across Chile were instructed to capture earwig specimens in their geographical area, to identify them and to provide material for genome sequencing to be carried out by themselves in their schools. RESULTS: The school students collected specimens from two cosmopolitan earwig species: Euborellia annulipes (Fam. Anisolabididae) and Forficula auricularia (Fam. Forficulidae). Genomic DNA was extracted and, with the help of scientific teams that traveled to the schools, was sequenced using nanopore sequencers. The sequence data obtained for both species was assembled and annotated. We obtained genome sizes of 1.18 Gb (F. auricularia) and 0.94 Gb (E. annulipes) with the number of predicted protein coding genes being 31,800 and 40,000, respectively. Our analysis showed that we were able to capture a high percentage (≥ 93%) of conserved proteins indicating genomes that are useful for comparative and functional analysis. We were also able to characterize structural elements such as repetitive sequences and non-coding RNA genes. Finally, functional categories of genes that are overrepresented in each species suggest important differences in the process underlying the formation of germ cells, and modes of reproduction between them, features that are one of the distinguishing biological properties that characterize these two distant families of Dermaptera. CONCLUSIONS: This work represents an unprecedented instance where the scientific and lay community have come together to collaborate in a genome sequencing project. The versatility and accessibility of nanopore sequencers was key to the success of the initiative. We were able to obtain full genome sequences of two important and widely distributed species of insects which had not been analyzed at this level previously. The data made available by the project should illuminate future studies on the Dermaptera.

The highly diverse Antarctic Peninsula soil microbiota as a source of novel resistance genes.

The rise of multiresistant bacterial pathogens is currently one of the most critical threats to global health, encouraging a better understanding of the evolution and spread of antimicrobial resistance. In this regard, the role of the environment as a source of resistance mechanisms remains poorly understood. Moreover, we still know a minimal part of the microbial diversity and resistome present in remote and extreme environments, hosting microbes that evolved to resist harsh conditions and thus a potentially rich source of novel resistance genes. This work demonstrated that the Antarctic Peninsula soils host a remarkable microbial diversity and a widespread presence of autochthonous antibiotic-resistant bacteria and resistance genes. We observed resistance to a wide array of antibiotics among isolates, including Pseudomonas resisting ten or more different compounds, with an overall increased resistance in bacteria from non-intervened areas. In addition, genome analysis of selected isolates showed several genes encoding efflux pumps, as well as a lack of known resistance genes for some of the resisted antibiotics, including colistin, suggesting novel uncharacterized mechanisms. By combining metagenomic approaches based on analyzing raw reads, assembled contigs, and metagenome-assembled genomes, we found hundreds of widely distributed genes potentially conferring resistance to different antibiotics (including an outstanding variety of inactivation enzymes), metals, and biocides, hosted mainly by Polaromonas, Pseudomonas, Streptomyces, Variovorax, and Burkholderia. Furthermore, a proportion of these genes were found inside predicted plasmids and other mobile elements, including a putative OXA-like carbapenemase from Polaromonas harboring conserved key residues and predicted structural features. All this evidence indicates that the Antarctic Peninsula soil microbiota has a broad natural resistome, part of which could be transferred horizontally to pathogenic bacteria, acting as a potential source of novel resistance genes.

Genome sequencing and transcriptomic analysis of the Andean killifish Orestias ascotanensis reveals adaptation to high-altitude aquatic life.

Orestias ascotanensis (Cyprinodontidae) is a teleost pupfish endemic to springs feeding into the Ascotan saltpan in the Chilean Altiplano (3,700 m.a.s.l.) and represents an opportunity to study adaptations to high-altitude aquatic environments. We have de novo assembled the genome of O. ascotanensis at high coverage. Comparative analysis of the O. ascotanensis genome showed an overall process of contraction, including loss of genes related to G-protein signaling, chemotaxis and signal transduction, while there was expansion of gene families associated with microtubule-based movement and protein ubiquitination. We identified 818 genes under positive selection, many of which are involved in DNA repair. Additionally, we identified novel and conserved microRNAs expressed in O. ascotanensis and its closely-related species, Orestias gloriae. Our analysis suggests that positive selection and expansion of genes that preserve genome stability are a potential adaptive mechanism to cope with the increased solar UV radiation to which high-altitude animals are exposed to.

Pedro Leandro Fariñas Mayo: erudito profesor de Radiología, Hijo Preclaro y Distinguido de Santa Clara / Pedro Leandro Fariñas Mayo: erudite professor of Radiology, Preclear and Distinguished Son of Santa Clara

RESUMEN Entre los que dieron un aporte importante al desarrollo y enseñanza de la Radiología en Cuba, se destaca el doctor santaclareño Pedro Leandro Fariñas Mayo. Radiólogo eminente que dedicó su vida a la asistencia, investigación y docencia de esa especialidad. Múltiples sociedades científicas, colegios y academias del mundo lo hicieron miembro honorario. Publicó más de 100 artículos en revistas cubanas y extranjeras y llegó a ser miembro del cuerpo de redactores de la Revista Médica Cubana. Como reconocimiento, el ayuntamiento de su ciudad natal le entregó el título de Hijo Preclaro y Distinguido de la ciudad de Santa Clara. Es objetivo de los autores comunicar sobre su obra a fin de que las actuales generaciones de profesionales cubanos reconozcan su repercusión en la medicina cubana.

ABSTRACT Among those who made an important contribution to the development and teaching of Radiology in Cuba, Dr. Pedro Leandro Fariñas Mayo from Santa Clara stands out. Eminent radiologist who dedicated his life to assisting, researching and teaching this specialty. Multiple scientific societies, colleges and academies around the world made him an honorary member. He published more than 100 articles in Cuban and foreign journals and became a member of the editorial staff of the Cuban Medical Journal. In recognition, the city council of his hometown gave him the title of Prominent and Distinguished Son of the city of Santa Clara. It is the objective of the authors to communicate about his work so that current generations of Cuban professionals recognize its impact on Cuban medicine.

Dysregulated Immune Responses in COVID-19 Patients Correlating With Disease Severity and Invasive Oxygen Requirements.

The prognosis of severe COVID-19 patients has motivated research communities to uncover mechanisms of SARS-CoV-2 pathogenesis also on a regional level. In this work, we aimed to understand the immunological dynamics of severe COVID-19 patients with different degrees of illness, and upon long-term recovery. We analyzed immune cellular subsets and SARS-CoV-2-specific antibody isotypes of 66 COVID-19 patients admitted to the Hospital Clínico Universidad de Chile, which were categorized according to the WHO ten-point clinical progression score. These included 29 moderate patients (score 4-5) and 37 severe patients under either high flow oxygen nasal cannula (18 patients, score 6), or invasive mechanical ventilation (19 patients, score 7-9), plus 28 convalescent patients and 28 healthy controls. Furthermore, six severe patients that recovered from the disease were longitudinally followed over 300 days. Our data indicate that severe COVID-19 patients display increased frequencies of plasmablasts, activated T cells and SARS-CoV-2-specific antibodies compared to moderate and convalescent patients. Remarkably, within the severe COVID-19 group, patients rapidly progressing into invasive mechanical ventilation show higher frequencies of plasmablasts, monocytes, eosinophils, Th1 cells and SARS-CoV-2-specific IgG than patients under high flow oxygen nasal cannula. These findings demonstrate that severe COVID-19 patients progressing into invasive mechanical ventilation show a distinctive type of immunity. In addition, patients that recover from severe COVID-19 begin to regain normal proportions of immune cells 100 days after hospital discharge and maintain high levels of SARS-CoV-2-specific IgG throughout the study, which is an indicative sign of immunological memory. Thus, this work can provide useful information to better understand the diverse outcomes of severe COVID-19 pathogenesis.

Plant ecological genomics at the limits of life in the Atacama Desert.

The Atacama Desert in Chile-hyperarid and with high-ultraviolet irradiance levels-is one of the harshest environments on Earth. Yet, dozens of species grow there, including Atacama-endemic plants. Herein, we establish the Talabre-Lejía transect (TLT) in the Atacama as an unparalleled natural laboratory to study plant adaptation to extreme environmental conditions. We characterized climate, soil, plant, and soil-microbe diversity at 22 sites (every 100 m of altitude) along the TLT over a 10-y period. We quantified drought, nutrient deficiencies, large diurnal temperature oscillations, and pH gradients that define three distinct vegetational belts along the altitudinal cline. We deep-sequenced transcriptomes of 32 dominant plant species spanning the major plant clades, and assessed soil microbes by metabarcoding sequencing. The top-expressed genes in the 32 Atacama species are enriched in stress responses, metabolism, and energy production. Moreover, their root-associated soils are enriched in growth-promoting bacteria, including nitrogen fixers. To identify genes associated with plant adaptation to harsh environments, we compared 32 Atacama species with the 32 closest sequenced species, comprising 70 taxa and 1,686,950 proteins. To perform phylogenomic reconstruction, we concatenated 15,972 ortholog groups into a supermatrix of 8,599,764 amino acids. Using two codon-based methods, we identified 265 candidate positively selected genes (PSGs) in the Atacama plants, 64% of which are located in Pfam domains, supporting their functional relevance. For 59/184 PSGs with an Arabidopsis ortholog, we uncovered functional evidence linking them to plant resilience. As some Atacama plants are closely related to staple crops, these candidate PSGs are a "genetic goldmine" to engineer crop resilience to face climate change.

Caracterización clínica y radiológica de pacientes positivos a la COVID-19 / Clinical and radiological characterization of COVID-19 positive patients

Introducción: Desde el surgimiento de los primeros casos en la pandemia de la COVID-19, se ha desarrollado una carrera vertiginosa en crear un espacio de investigación para el diagnóstico, tratamiento y control de la enfermedad. Objetivo: Describir las características clínicas y radiológicas de los pacientes con la COVID-19. Métodos: Se realizó un estudio descriptivo, en el período comprendido de marzo a octubre del año 2020, se estudiaron 404 pacientes de todas las edades, ingresados, con diagnóstico confirmado con PCR en tiempo real. Las variables utilizadas fueron: edad, sexo, síntomas y radiografía del tórax. Resultados: El 54,5 por ciento de los pacientes fueron del sexo femenino y entre ellos asintomáticos el 55,9 por ciento; el 36,9 por ciento tenía entre 40 a 59 años de edad, en los menores de 20 años, el 64,9 por ciento no presentó síntomas de la enfermedad al ingreso. Estuvieron asintomáticos el 53,5 por ciento; el 76,6 por ciento de las radiografías positivas correspondieron a los sintomáticos, la tos fue el síntoma más frecuente. La mayor positividad en la radiografía del tórax se encontró en los pacientes mayores de 60 años, se observó como patrón más frecuente, la opacidad en velo, de distribución periférica. Conclusiones: Predominan los pacientes asintomáticos, la positividad de las radiografías es mayor en los ancianos(AU)

Introduction: Since the emergence of the first cases of COVID-19 pandemic, a dizzying race has developed in creating a research space for the diagnosis, treatment and control of the disease. Objective: To describe the clinical and radiological characteristics of patients with COVID-19. Methods: A descriptive study was carried out, in the period from March to October 2020, 404 patients of all ages, admitted, with confirmed diagnosis with real-time PCR, were studied. The variables used were: age, sex, symptoms and chest X-ray. Results: 54.5 percent of the patients were female and 55,9 percent of them were asymptomatic, 36,9 percent were between 40 and 59 years old, in those under 20 years 64,9 percent were not. They presented symptoms of the disease upon admission 53,5 percent were asymptomatic, 76,6 percent of the positive radiographs corresponded to the symptomatic ones, coughing was the most frequent symptom. The greatest positivity in the chest X-ray was found in patients older than 60 years, the most frequent pattern was the opacity in the peripheral distribution veil. Conclusions: Asymptomatic patients predominate, the positivity of radiographs is higher in the elderly(AU)

Triadimefon triggers circling behavior and conditioned place preference/aversion in zebrafish in a dose dependent manner.

Triadimefon (TDF) is a pesticide used in agricultural crops to control powdery mildews, rusts and other fungal pests. It exerts its fungicidal activity through the inhibition of ergosterol biosynthesis, impairing the formation of the cell membrane. For vertebrates, one of its side effects is the binding to the dopamine transporter increasing the levels of synaptic dopamine, similarly to cocaine. In addition, it has been demonstrated that TDF affects the abundance of other monoamines in the brain, specifically serotonin. It is well known that drugs which alter the dopaminergic and serotonergic systems produce behavioral changes and participate in the development of addictions in mammals. In this work we have used the conditioned place preference paradigm to assess, for the first time, the rewarding properties of TDF in zebrafish. We found out that TDF triggers both, preference and aversion depending on the dosage used during conditioning. We observed that 5 mg/L produced aversion to the pattern previously paired with TDF. However, 15 mg/L induced the opposite behavior, showing that zebrafish seek out those environments which had previously been paired with the higher dose of TDF. These results are congruent with our previous findings, where we showed that 5 mg/L reduced the levels of serotonin, usually linked to anxious behaviors (a negative cue), whereas higher concentrations of TDF increased extracellular dopamine, the main currency of the reward system. Interestingly, both doses of TDF induced circling behavior, a feature usually seen in glutamatergic antagonists.

Current Advances in Comprehending Dynamics of Regenerating Axons and Axon-Glia Interactions after Peripheral Nerve Injury in Zebrafish.

Following an injury, axons of both the central nervous system (CNS) and peripheral nervous system (PNS) degenerate through a coordinated and genetically conserved mechanism known as Wallerian degeneration (WD). Unlike central axons, severed peripheral axons have a higher capacity to regenerate and reinnervate their original targets, mainly because of the favorable environment that they inhabit and the presence of different cell types. Even though many aspects of regeneration in peripheral nerves have been studied, there is still a lack of understanding regarding the dynamics of axonal degeneration and regeneration, mostly due to the inherent limitations of most animal models. In this scenario, the use of zebrafish (Danio rerio) larvae combined with time-lapse microscopy currently offers a unique experimental opportunity to monitor the dynamics of the regenerative process in the PNS in vivo. This review summarizes the current knowledge and advances made in understanding the dynamics of the regenerative process of PNS axons. By using different tools available in zebrafish such as electroablation of the posterior lateral line nerve (pLLn), and laser-mediated transection of motor and sensory axons followed by time-lapse microscopy, researchers are beginning to unravel the complexity of the spatiotemporal interactions among different cell types during the regenerative process. Thus, understanding the cellular and molecular mechanisms underlying the degeneration and regeneration of peripheral nerves will open new avenues in the treatment of acute nerve trauma or chronic conditions such as neurodegenerative diseases.

Six decades of scientific pan-Americanism - an interview with Jorge E. Allende.

Jorge E. Allende is a biochemist trained in the United States of America who has been a professor at the University of Chile since 1961. He has served in many leadership positions in both Chilean and international scientific organizations and academic institutions. He led the International Cell Research Organization, the Latin American Network of Biological Sciences and obtained the Chilean National Science Prize. He belongs to the Chilean Academy of Sciences and is a foreign member of the National Academy of Sciences (USA) and also of the National Academy of Medicine (USA). During his career, besides leading a highly successful research group, he was instrumental in generating an esprit de corps among Latin American scientists of all fields in biology starting in the late 1960's. He began a longstanding tradition by organizing advanced training courses for young scientists from the region who would not have otherwise had the opportunity to experience the latest methods and concepts in biological research, courses that had world leading researchers as instructors. A constant focus of his efforts consisted in promoting the establishment of postgraduate programs in biology throughout the continent, coordinating international funding programs aimed at scientific development in the third world and, more recently, advocating for science education among children and school teachers as the only way to achieve scientific literacy in our societies. In this interview, we explore how these issues were addressed by him and his counterparts in other Latin American countries, at a time when they had to start, essentially, from scratch.