Multi-Scale Imaging of the Dynamic Organization of Chromatin.

Chromatin is now regarded as a heterogeneous and dynamic structure occupying a non-random position within the cell nucleus, where it plays a key role in regulating various functions of the genome. This current view of chromatin has emerged thanks to high spatiotemporal resolution imaging, among other new technologies developed in the last decade. In addition to challenging early assumptions of chromatin being regular and static, high spatiotemporal resolution imaging made it possible to visualize and characterize different chromatin structures such as clutches, domains and compartments. More specifically, super-resolution microscopy facilitates the study of different cellular processes at a nucleosome scale, providing a multi-scale view of chromatin behavior within the nucleus in different environments. In this review, we describe recent imaging techniques to study the dynamic organization of chromatin at high spatiotemporal resolution. We also discuss recent findings, elucidated by these techniques, on the chromatin landscape during different cellular processes, with an emphasis on the DNA damage response.

Global chromatin mobility induced by a DSB is dictated by chromosomal conformation and defines the HR outcome.

Repair of DNA double-strand breaks (DSBs) is crucial for genome integrity. A conserved response to DSBs is an increase in chromatin mobility that can be local, at the site of the DSB, or global, at undamaged regions of the genome. Here, we address the function of global chromatin mobility during homologous recombination (HR) of a single, targeted, controlled DSB. We set up a system that tracks HR in vivo over time and show that two types of DSB-induced global chromatin mobility are involved in HR, depending on the position of the DSB. Close to the centromere, a DSB induces global mobility that depends solely on H2A(X) phosphorylation and accelerates repair kinetics, but is not essential. In contrast, the global mobility induced by a DSB away from the centromere becomes essential for HR repair and is triggered by homology search through a mechanism that depends on H2A(X) phosphorylation, checkpoint progression, and Rad51. Our data demonstrate that global mobility is governed by chromosomal conformation and differentially coordinates repair by HR.

The Dynamic Behavior of Chromatin in Response to DNA Double-Strand Breaks.

The primary functions of the eukaryotic nucleus as a site for the storage, retrieval, and replication of information require a highly dynamic chromatin organization, which can be affected by the presence of DNA damage. In response to double-strand breaks (DSBs), the mobility of chromatin at the break site is severely affected and, to a lesser extent, that of other chromosomes. The how and why of such movement has been widely studied over the last two decades, leading to different mechanistic models and proposed potential roles underlying both local and global mobility. Here, we review the state of the knowledge on current issues affecting chromatin mobility upon DSBs, and highlight its role as a crucial step in the DNA damage response (DDR).

Virulence assessment of enterohepatic Helicobacter species carried by dogs using the wax moth larvae Galleria mellonella as infection model.

BACKGROUND: Enterohepatic species of the genus Helicobacter (EHH) are emerging pathogens that have been associated with gastrointestinal and hepatobiliary diseases in humans. However, studies on their pathogenicity are scarce. Galleria mellonella is a recently proposed model for the study of virulence in different pathogens, such as Campylobacter spp. and Helicobacter pylori. Despite this, its usefulness in EHH has not yet been evaluated. Therefore, we determined the pathogenic potential of different EHH species isolated from dogs in this infection model. MATERIALS AND METHODS: Four species of EHH (H. bilis, H. canicola, H. canis, and 'H. winghamensis') isolated from fecal samples from domestic dogs were evaluated. Three strains of each species were inoculated in cohorts of G. mellonella at a concentration of 1 × 107  CFU/mL. Survival curves were determined by the Kaplan-Meier method. In addition, the quantification of melanin, bacterial load in hemolymph, and histopathology were evaluated daily post-infection (pi). RESULTS: G. mellonella larvae are susceptible to EHH infection, exhibiting intra- and inter-species variability. Melanin production became evident from 4 h pi and increased throughout the assay. All species were recovered from the hemolymph after 20 min pi; however, only H. canis could be recovered up to 48 h pi. Histopathology revealed cellular and humoral immune response, evidencing accumulation of hemocytes, nodulation, and melanin deposition in different tissues. CONCLUSION: EHH species carried by dogs have considerable pathogenic potential, being H. canicola the species with the highest degree of virulence. Thus, G. mellonella is a useful model to assess virulence in these emerging pathogens.

Modified chromosome structure caused by phosphomimetic H2A modulates the DNA damage response by increasing chromatin mobility in yeast.

In budding yeast and mammals, double-strand breaks (DSBs) trigger global chromatin mobility together with rapid phosphorylation of histone H2A over an extensive region of the chromatin. To assess the role of H2A phosphorylation in this response to DNA damage, we have constructed strains where H2A has been mutated to the phosphomimetic H2A-S129E. We show that mimicking H2A phosphorylation leads to an increase in global chromatin mobility in the absence of DNA damage. The intrinsic chromatin mobility of H2A-S129E is not due to downstream checkpoint activation, histone degradation or kinetochore anchoring. Rather, the increased intrachromosomal distances observed in the H2A-S129E mutant are consistent with chromatin structural changes. Strikingly, in this context the Rad9-dependent checkpoint becomes dispensable. Moreover, increased chromatin dynamics in the H2A-S129E mutant correlates with improved DSB repair by non-homologous end joining and a sharp decrease in interchromosomal translocation rate. We propose that changes in chromosomal conformation due to H2A phosphorylation are sufficient to modulate the DNA damage response and maintain genome integrity.This article has an associated First Person interview with the first author of the paper.

Inmunodeficiencia Combinada Severa, reporte de pacientes chilenos diagnosticados durante el período 1999-2020 / Severe combined immunodeficiency, report of Chilean patients diagnosed during the 1999-2020 period

INTRODUCCIÓN: La inmunodeficiencia combinada severa (IDCS) corresponde a una de las formas más graves de inmunodeficiencia primaria, existiendo escasos datos nacionales sobre ésta. OBJETIVO: describir la epidemiología, complicaciones, pronóstico y uso de la vacuna BCG en pacientes chilenos con IDCS. PACIENTES Y MÉTODO: Estudio retrospectivo de pacientes diagnosticados con IDCS entre los años 1999 y 2020 por médicos inmunólogos a lo largo de Chile. El diagnóstico de IDCS se realizó conforme a los criterios propuestos por Shearer: linfocitos T (CD3+) < 300 células/μL y prolife ración 10% del límite de normalidad en respuesta a fitohemaglutinina o presencia de linfocitos T de origen materno. Se obtuvieron de la ficha clínica los datos correspondientes a: sexo, edad al diagnóstico, consanguinidad, región de origen, subpoblaciones linfocitarias, diagnóstico genético, complicaciones infecciosas y no infecciosas, vacunación BCG y sus complicaciones, edad de deriva ción al centro de TPH y causa de mortalidad no relacionada al TPH. RESULTADOS: se diagnosticaron 25 casos de IDCS en 22 familias entre los años 1999-2020. 78% varones, la edad media a la primera manifestación fue 2.3 meses (0-7), mientras que la edad media al diagnóstico fue de 3.4 meses (0 7). Un 16% de los casos tenía un antecedente familiar de IDCS. Un 40% de los casos fueron diag nosticados en la Región Metropolitana. El inmunofenotipo más frecuente fue T-B-NK+ (48%). Se realizaron estudios genéticos en 69,5% de los casos, siendo los defectos genéticos en RAG2 (39%) la causa más frecuente. Un 88% de los casos recibió la vacuna Bacillus Calmette-Guerin (BCG) previo al diagnóstico, incluidos 2 pacientes con historia familiar positiva, 36% de los vacunados experimentó complicaciones de la BCG. La edad media a la derivación a trasplante fue de 7,4 meses (5-16). De los 25 pacientes, 11 fallecieron previo a la derivación a un centro de trasplante. CONCLUSIÓN: En Chile existe un retraso clínicamente significativo entre las primeras manifestaciones y el diagnóstico de IDCS, así como un importante retraso en la derivación a centros de trasplante. La mayoría de los pacientes con IDCS reciben la vacuna BCG, pese a tener antecedentes familiares, y experimentan frecuentemente complicaciones de la vacuna.

INTRODUCTION: Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency. To date, there is little local information about this disease. OBJECTIVE: To describe the epidemiology, complications, prognosis, and use of the BCG vaccine in Chilean patients with SCID. PATIENTS AND METHOD: Retrospective review of the clinical records of patients diagnosed with SCID by clinical immunologists between 1999 and 2020 throughout Chile. SCID was diagnosed according to the cri teria proposed by Shearer: T lymphocytes (CD3+) < 300 cells/μL and proliferation 10% of the limit of normality in response to phytohemagglutinin or presence of T lymphocytes of maternal origin. Data collected from the clinical records were: sex, age at diagnosis, consanguinity, region of origin, lymphocyte subpopulations, genetic diagnosis, infectious and non-infectious complications, BCG vaccination and its complications, age at referral to the bone marrow transplant (BMT) center, and cause of non-BMT-related mortality. RESULTS: Between 1999 and 2020, 25 patients were diagnosed with SCID. 78% of them were male, mean age at first manifestation of the disease was 2.3 months (0-7), while the mean age at diagnosis was 3.4 months (0-7). 16% of patients had a family history of SCID. 40% of cases were diagnosed within the Metropolitan Region. The most frequent immuno- phenotype was T-B-NK+ SCID (48%). Genetic studies were done in 69.5% of cases, mutations in the RAG2 gene were the most common etiology of SCID (39%). 88% of SCID patients received the Bacillus Calmette-Guerin (BCG) vaccine before diagnosis, including 2 cases with a known family history of SCID. 36% of those who received the vaccine had BCG-related complications. The mean age at referral to a bone marrow transplant center was 7.4 months (5-16). 11/25 patients died before being transferred to a transplant center. DISCUSSION: There is a clinically significant delay between the first manifestations and the diagnosis of SCID in Chilean patients, as well as an important time gap between the diagnosis of SCID and referral to a center for BMT. Most SCID cases in Chile receive the BCG vaccine, despite a known family history of the disease, and frequently develop vaccine-related complications.

[Severe combined immunodeficiency, report of chilean patients diagnosed during the 1999-2020 period]. / Inmunodeficiencia Combinada Severa, reporte de pacientes chilenos diagnosticados durante el período 1999-2020.

INTRODUCTION: Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency. To date, there is little local information about this disease. OBJECTIVE: To describe the epidemiology, complications, prognosis, and use of the BCG vaccine in Chilean patients with SCID. PATIENTS AND METHOD: Retrospective review of the clinical records of patients diagnosed with SCID by clinical immunologists between 1999 and 2020 throughout Chile. SCID was diagnosed according to the cri teria proposed by Shearer: T lymphocytes (CD3+) < 300 cells/µL and proliferation 10% of the limit of normality in response to phytohemagglutinin or presence of T lymphocytes of maternal origin. Data collected from the clinical records were: sex, age at diagnosis, consanguinity, region of origin, lymphocyte subpopulations, genetic diagnosis, infectious and non-infectious complications, BCG vaccination and its complications, age at referral to the bone marrow transplant (BMT) center, and cause of non-BMT-related mortality. RESULTS: Between 1999 and 2020, 25 patients were diagnosed with SCID. 78% of them were male, mean age at first manifestation of the disease was 2.3 months (0-7), while the mean age at diagnosis was 3.4 months (0-7). 16% of patients had a family history of SCID. 40% of cases were diagnosed within the Metropolitan Region. The most frequent immuno- phenotype was T-B-NK+ SCID (48%). Genetic studies were done in 69.5% of cases, mutations in the RAG2 gene were the most common etiology of SCID (39%). 88% of SCID patients received the Bacillus Calmette-Guerin (BCG) vaccine before diagnosis, including 2 cases with a known family history of SCID. 36% of those who received the vaccine had BCG-related complications. The mean age at referral to a bone marrow transplant center was 7.4 months (5-16). 11/25 patients died before being transferred to a transplant center. DISCUSSION: There is a clinically significant delay between the first manifestations and the diagnosis of SCID in Chilean patients, as well as an important time gap between the diagnosis of SCID and referral to a center for BMT. Most SCID cases in Chile receive the BCG vaccine, despite a known family history of the disease, and frequently develop vaccine-related complications.

Chromatin stiffening underlies enhanced locus mobility after DNA damage in budding yeast.

DNA double-strand breaks (DSBs) induce a cellular response that involves histone modifications and chromatin remodeling at the damaged site and increases chromosome dynamics both locally at the damaged site and globally in the nucleus. In parallel, it has become clear that the spatial organization and dynamics of chromosomes can be largely explained by the statistical properties of tethered, but randomly moving, polymer chains, characterized mainly by their rigidity and compaction. How these properties of chromatin are affected during DNA damage remains, however, unclear. Here, we use live cell microscopy to track chromatin loci and measure distances between loci on yeast chromosome IV in thousands of cells, in the presence or absence of genotoxic stress. We confirm that DSBs result in enhanced chromatin subdiffusion and show that intrachromosomal distances increase with DNA damage all along the chromosome. Our data can be explained by an increase in chromatin rigidity, but not by chromatin decondensation or centromeric untethering only. We provide evidence that chromatin stiffening is mediated in part by histone H2A phosphorylation. Our results support a genome-wide stiffening of the chromatin fiber as a consequence of DNA damage and as a novel mechanism underlying increased chromatin mobility.

Draft Genome Sequences of Five Enterococcus Species Isolated from the Gut of Patients with Suspected Clostridium difficile Infection.

We present draft genome sequences of five Enterococcus species from patients suspected of Clostridium difficile infection. Genome completeness was confirmed by presence of bacterial orthologs (97%). Gene searches using Hidden-Markov models revealed that the isolates harbor between seven and 11 genes involved in antibiotic resistance to tetracyclines, beta-lactams, and vancomycin.

Deficiencia de anticuerpos específicos: inmunodeficiencia primaria asociada a alergia respiratoria / Specific antibody deficiency: primary immunodeficiency associated to respiratory allergy

La deficiencia de anticuerpos específicos con inmunoglobulinas séricas y linfocitos B normales (SAD) es una inmunodeficiencia primaria caracterizada por una capacidad alterada de responder a antígenos específicos, especialmente polisacáridos. OBJETIVO: Describir las características clínicas de pacientes con SAD y destacar la asociación entre una inmunodeficiencia primaria y enfermedades alérgicas. Pacientes y Método: Estudio descriptivo en enfermos con SAD atendidos en un hospital público entre agosto de 2007 y julio de 2015. Se descartó otra inmunodeficiencia primaria o secundaria. El diagnóstico se basó en infecciones recurrentes y una respuesta anormal a la vacuna neumocócica polisacárida con medición de IgG específica para 10 serotipos de neumococo. RESULTADOS: Se incluyeron 12 pacientes, 4 varones, con una edad promedio de 6 años; predominaron las neumonías recurrentes (91,7%) y otras infecciones respiratorias e invasivas. Los 12 enfermos con SAD tenían asma asociada; 11, rinitis alérgica y otras alergias. Tres pacientes no respondieron a ninguno de los 10 serotipos contenidos en la vacuna neumocócica polisacárida y la mayoría de los que lo hicieron fue a títulos bajos. El tratamiento con vacuna neumocócica conjugada fue favorable en 11/12 enfermos. CONCLUSIÓN: En niños mayores de 2 años con infecciones respiratorias recurrentes o infecciones invasivas por S. pneumoniae con inmunoglobulinas normales recomendamos investigar SAD, más aún si tienen enfermedad alérgica asociada.

Specific antibody deficiency (SAD) with normal immunoglobulin and normal B cells is a primary immunodeficiency characterized by reduced ability to produce antibodies to specific antigens especially polysaccharides. OBJECTIVE: To describe the characteristics of patients diagnosed with SAD emphasizing the association between primary immunodeficiency and allergic diseases. PATIENTS AND METHOD: Descriptive study showing patients with SAD treated at a public hospital between August 2007 and July 2015. Other secondary or primary immunodeficiency was discarded. The diagnosis of SAD was based on recurrent infections and abnormal response to pneumococcal polysaccharide vaccine assessed by specific IgG to 10 pneumococcal serotypes. Results: Twelve patients were included, 4 males, mean age 6 years, recurrent pneumonia predominated (91.7%) as well as other respiratory and invasive infections. All patients with SAD had associated asthma, 11 had allergic rhinitis, and other allergies. Three patients did not respond to any of the 10 serotypes contained in pneumococcal polysaccharide vaccine, and those who responded were with low titers. Treatment with conjugate pneumococcal vaccine was favorable in 11/12 patients. CONCLUSION: In children older than 2 years with recurrent respiratory infections or invasive S. pneumoniae infections with normal immunoglobulin we recommend to investigate SAD, especially if they have a concurrent allergic disease.

[Specific antibody deficiency: Primary immunodeficiency associated to respiratory allergy]. / Deficiencia de anticuerpos específicos: inmunodeficiencia primaria asociada a alergia respiratoria.

Specific antibody deficiency (SAD) with normal immunoglobulin and normal B cells is a primary immunodeficiency characterized by reduced ability to produce antibodies to specific antigens especially polysaccharides. OBJECTIVE: To describe the characteristics of patients diagnosed with SAD emphasizing the association between primary immunodeficiency and allergic diseases. PATIENTS AND METHOD: Descriptive study showing patients with SAD treated at a public hospital between August 2007 and July 2015. Other secondary or primary immunodeficiency was discarded. The diagnosis of SAD was based on recurrent infections and abnormal response to pneumococcal polysaccharide vaccine assessed by specific IgG to 10 pneumococcal serotypes. RESULTS: Twelve patients were included, 4 males, mean age 6 years, recurrent pneumonia predominated (91.7%) as well as other respiratory and invasive infections. All patients with SAD had associated asthma, 11 had allergic rhinitis, and other allergies. Three patients did not respond to any of the 10 serotypes contained in pneumococcal polysaccharide vaccine, and those who responded were with low titers. Treatment with conjugate pneumococcal vaccine was favorable in 11/12 patients. CONCLUSION: In children older than 2 years with recurrent respiratory infections or invasive S. pneumoniae infections with normal immunoglobulin we recommend to investigate SAD, especially if they have a concurrent allergic disease.

[The trajectory of the introduction and regulation of acupuncture in Brazil: recollections of the challenges and struggles]. / A trajetória da introdução e regulamentação da acupuntura no Brasil: memórias de desafios e lutas.

Based on the life experiences of acupuncturists, the scope of this study was to examine the struggle to obtain regulation of the practice of acupuncture in Brazil. The method used was Oral Live History, the core issue being the dimension of the human experience involved in this trajectory of struggles and challenges. We conducted ten interviews, following the set of procedures demanded by the Oral History technique. The information contained in the narratives was analyzed and, taking the interpretive approach called immersion/crystallization as a benchmark, the central themes of the work were established, based on which which the discussion was developed. The results indicate the emergence of highly controversial themes involving political, corporate and cultural aspects, which constitute central elements within a historical process still under development.

A trajetória da introdução e regulamentação da acupuntura no Brasil: memórias de desafios e lutas / The trajectory of the introduction and regulation of acupuncture in Brazil: memories of challenges and struggles

O presente estudo objetivou explorar, a partir de relatos de vida de acupunturistas, a luta pela regulamentação da prática da acupuntura no Brasil. Utilizamos a História Oral de Vida como método, tendo como proposta central a dimensão das experiências humanas envolvidas nesta trajetória de lutas e desafios. Realizamos dez entrevistas, seguindo o conjunto de procedimentos exigidos pela História Oral. As informações contidas nas narrativas foram analisadas e, tomando como referencial a abordagem de interpretação denominada imersão/cristalização, foram estabelecidos os temas centrais do trabalho, a partir dos quais a discussão foi desenvolvida. Os resultados apontaram a emergência de temas extremamente controversos que envolvem aspectos políticos, corporativos e de âmbito cultural, que se apresentam como elementos centrais dentro de um processo histórico ainda em desenvolvimento.

Adhesive and invasive capacities of Edwardsiella tarda isolated from South American sea lion.

Edwarsiella tarda is a zoonotic bacterium that can be isolated from humans, animals and the environment. Although E. tarda is primarily considered a fish pathogen, it is the only species of its genus considered to be pathogenic for humans as well. A survey of zoonotic intestinal bacteria in fresh feces from South American sea lions (SASL) Otaria flavescens, reported E. tarda as the most frequently isolated species. In this study, we used HEp-2 cells to establish in vitro the adherence and invasive ability of 17 E. tarda strains isolated from SASL fecal material. All the strains were able to adhere and invade HEp-2 cells with adhesion and invasion percentages ranging from 56 to 100% and 21 to 74%, respectively. Despite the expression of these pathogenic factors, further investigation is needed to determine whether this bacterium could play a role as primary pathogen for this and other species of pinnipeds.

Adhesive and invasive capacities of Edwarsiella tarda isolated from South American sea lion

Edwarsiella tarda is a zoonotic bacterium that can be isolated from humans, animals and the environment. Although E. tarda is primarily considered a fish pathogen, it is the only species of its genus considered to be pathogenic for humans as well. A survey of zoonotic intestinal bacteria in fresh feces from South American sea lions (SASL) Otaria flavescens, reported E. tarda as the most frequently isolated species. In this study, we used HEp-2 cells to establish in vitro the adherence and invasive ability of 17 E. tarda strains isolated from SASL fecal material. All the strains were able to adhere and invade HEp-2 cells with adhesion and invasion percentages ranging from 56 to 100% and 21 to 74%, respectively. Despite the expression of these pathogenic factors, further investigation is needed to determine whether this bacterium could play a role as primary pathogen for this and other species of pinnipeds.

A acupuntura no Sistema Único de Saúde no município de São Paulo: história e memória / Acupuncture in the Unified Health System in São Paulo: history and memory

Introdução: A Medicina Tradicional Chinesa é um vasto campo de saberes e práticas construídas a partir de uma concepção holística sobre a natureza do ser humano e suas relações com o mundo que o cerca e do qual faz parte. A acupuntura é uma modalidade de tratamento da Medicina Tradicional Chinesa que visa à terapia das doenças e desarmonias pela aplicação de estímulos em locais anatômicos definidos. Objetivos: O presente estudo, ainda em fase de projeto científico, objetiva explorar as diversas fases que a acupuntura atravessou até sua aceitação no meio médico e inserção no Sistema Único de Saúde no Município de São Paulo, tomando como base as experiências de vida dos profissionais praticantes desta técnica. Método: Analisará, através das narrativas, como ocorre a mediação entre a visão da Medicina Chinesa e da Medicina Ocidental no espaço público, bem como o posicionamento dos diferentes praticantes de acupuntura quanto à necessidade da regulamentação desta prática no Brasil. Utilizaremos a História Oral de Vida como método, pois tal abordagem metodológica demonstra ser a mais adequada frente aos objetivos do projeto, não apenas devido à escassez de documentos escritos relacionados a este processo histórico, como também por responder melhor à intenção de acessarmos a dimensão das experiências humanas envolvidas nesta trajetória de lutas e desafios. A História Oral nos possibilita a construção de uma história mais humanizada, que concorde com os objetivos mais amplos deste projeto que se insere na linha de pesquisa de Humanidades e Humanização em Saúde. A História Oral segue um rigoroso conjunto de procedimentos para a constituição das narrativas, que garantem a ética e a validade das mesmas como documentos a serem analisados. As Etapas que compõem esse conjunto de procedimentos são: gravação das entrevistas; confecção do documento escrito: transcrição, textualização e transcriação; conferência e validação do documento escrito; análise; devolução do produto. Os resultados esperados consistem em instalar e ampliar novas linhas de pesquisa na área, preparação de artigos científicos para submissão a periódicos e congressos nessa linha, e, principalmente, a geração de informações e reflexões visando o enriquecimento dos marcos históricos da inserção da acupuntura no Município de São Paulo.

Functional and technological description of a real-time data management system for telehealthcare.

In health systems, there has been an emergence of new types of data and new technologies that allow continuously monitoring the status of the patients and make easy the achievement of real time information. The storage of all the acquired information makes possible to identify trends in medical data by means of new Clinical Decision Support subsystems. Current knowledge management solutions are specific, proprietary and closed and can not perform real-time analysis to improve the patient's diagnosis or treatment. There are neither solutions that integrate the large amount of heterogeneous information that nowadays are available in health environments. To overcome these objections, this paper proposes a new approach to design a data management system in a telehealthcare system with specific real-time constraints on knowledge acquisition and generation. It is a preliminary study and presents the main features of the system architecture and a preview of the technological solution implemented.