RESUMEN
In Saccharomyces cerevisiae, dicentric chromosomes stemming from telomere fusions preferentially break at the fusion. This process restores a normal karyotype and protects chromosomes from the detrimental consequences of accidental fusions. Here, we address the molecular basis of this rescue pathway. We observe that tandem arrays tightly bound by the telomere factor Rap1 or a heterologous high-affinity DNA binding factor are sufficient to establish breakage hotspots, mimicking telomere fusions within dicentrics. We also show that condensins generate forces sufficient to rapidly refold dicentrics prior to breakage by cytokinesis and are essential to the preferential breakage at telomere fusions. Thus, the rescue of fused telomeres results from a condensin- and Rap1-driven chromosome folding that favors fusion entrapment where abscission takes place. Because a close spacing between the DNA-bound Rap1 molecules is essential to this process, Rap1 may act by stalling condensins.
Asunto(s)
Adenosina Trifosfatasas/genética , Cromosomas Fúngicos/metabolismo , ADN de Hongos/genética , Proteínas de Unión al ADN/genética , Complejos Multiproteicos/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Proteínas de Unión a Telómeros/genética , Telómero/metabolismo , Factores de Transcripción/genética , Adenosina Trifosfatasas/metabolismo , Puntos de Rotura del Cromosoma , Cromosomas Fúngicos/ultraestructura , Citocinesis/genética , ADN de Hongos/metabolismo , Proteínas de Unión al ADN/metabolismo , Expresión Génica , Cariotipo , Modelos Genéticos , Complejos Multiproteicos/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/ultraestructura , Proteínas de Saccharomyces cerevisiae/metabolismo , Complejo Shelterina , Telómero/ultraestructura , Proteínas de Unión a Telómeros/metabolismo , Factores de Transcripción/metabolismoRESUMEN
Controlling the reduction midpoint potential of heme B is a key factor in many bioelectrochemical reactions, including long-range electron transport. Currently, there are a number of globular model protein systems to study this biophysical parameter; however, there are none for large polymeric protein model systems (e.g., the OmcS protein from G. sulfurreducens). Peptide amphiphiles, short peptides with a lipid tail that polymerize into fibrous structures, fill this gap. Here, we show a peptide amphiphile model system where one can tune the electrochemical potential of heme B by changing the loading ratio and peptide sequence. Changing the loading ratio resulted in the most significant increase, with values as high as -22 mV down to -224 mV. Circular dichroism spectra of certain sequences show Cotton effects at lower loading ratios that disappear as more heme B is added, indicating an ordered environment that becomes disrupted if heme B is overpacked. These findings can contribute to the design of functional self-assembling biomaterials.
Asunto(s)
Hemo , Oxidación-Reducción , Péptidos , Hemo/química , Péptidos/química , Secuencia de Aminoácidos , Tensoactivos/químicaRESUMEN
Dicentric chromosomes are unstable products of erroneous DNA repair events that can lead to further genome rearrangements and extended gene copy number variations. During mitosis, they form anaphase bridges, resulting in chromosome breakage by an unknown mechanism. In budding yeast, dicentrics generated by telomere fusion break at the fusion, a process that restores the parental karyotype and protects cells from rare accidental telomere fusion. Here, we observed that dicentrics lacking telomere fusion preferentially break within a 25- to 30-kb-long region next to the centromeres. In all cases, dicentric breakage requires anaphase exit, ruling out stretching by the elongated mitotic spindle as the cause of breakage. Instead, breakage requires cytokinesis. In the presence of dicentrics, the cytokinetic septa pinch the nucleus, suggesting that dicentrics are severed after actomyosin ring contraction. At this time, centromeres and spindle pole bodies relocate to the bud neck, explaining how cytokinesis can sever dicentrics near centromeres.
Asunto(s)
Centrómero/genética , Rotura Cromosómica , Cromosomas Fúngicos/genética , Citocinesis , Saccharomyces cerevisiae/genética , Telómero/metabolismo , División del Núcleo Celular , MitosisRESUMEN
BACKGROUND: Potentially inappropriate prescription (PIP) constitutes a risk for the development of adverse effects of a drug that outweigh its benefits, which can be considered inappropriate medication use. OBJECTIVE: To describe the prevalence of PIP in geriatric patients hospitalized at the internal medicine department of a referral hospital in Mexico. MATERIAL AND METHODS: Cross-sectional, descriptive design, with simple allocation of medical records from patients older than 65 years hospitalized between January 2016 and August 2017. The STOPP/START criteria were applied to identify the number of PIPs, the number of prescribed medications, number and type of comorbidities, as well as days of hospital stay. RESULTS: A prevalence of PIP of 73.3% was identified, with main comorbidities being hypertension and type 2 diabetes mellitus. A total of 1,885 prescribed medications were quantified; mean hospital stay was 6.3 days. CONCLUSIONS: A high prevalence of PIP was identified in hospitalized geriatric patients, hence the importance of applying the STOPP/START criteria and of the role of the pharmacist for validating the prescription prior to drug administration.
ANTECEDENTES: Una prescripción potencialmente inapropiada (PPI) constituye un riesgo de presentar efectos adversos por un fármaco que superan los beneficios de este, pudiendo considerarse como uso inadecuado de medicamentos. OBJETIVO: Describir la prevalencia de prescripciones potencialmente inapropiadas en pacientes geriátricos hospitalizados en el servicio de medicina interna de un hospital de referencia en México. MATERIAL Y MÉTODOS: Diseño descriptivo transversal, con asignación simple de expedientes clínicos de pacientes hospitalizados mayores de 65 años, entre enero de 2016 y agosto de 2017. Se aplicaron los criterios STOPP y START para identificar el número de PPI, cantidad de medicamentos prescritos, presencia, cantidad y tipo de comorbilidades, así como días de estancia hospitalaria. RESULTADOS: Se encontró una prevalencia de 73.3 % de PPI y las principales comorbilidades fueron hipertensión arterial y diabetes mellitus tipo 2. Se cuantificaron 1885 medicamentos prescritos; la estancia hospitalaria media fue de 6.3 días. CONCLUSIONES: Se identificó alta prevalencia de PPI en los pacientes geriátricos hospitalizados, de ahí la importancia de aplicar los criterios STOPP y START y del papel del farmacéutico en la validación de la prescripción antes de la administración de medicamentos.
Asunto(s)
Diabetes Mellitus Tipo 2 , Prescripción Inadecuada , Humanos , Anciano , Estudios Transversales , México , Hospitales , Derivación y ConsultaRESUMEN
The accurate detection of nucleic acids from certain biological pathogens is critical for the diagnosis of human diseases. However, amplified detection of RNA molecules from a complex sample by direct detection of RNA/DNA hybrids remains a challenge. Here, we show that type IIS endonuclease FokI is able to digest DNA duplexes and DNA/RNA hybrids when assisted by a dumbbell-like fluorescent sensing oligonucleotide. As proof of concept, we designed a battery of sensing oligonucleotides against specific regions of the SARS-CoV-2 genome and interrogated the role of FokI relaxation as a potential nicking enzyme for fluorescence signal amplification. FokI-assisted digestion of SARS-CoV-2 probes increases the detection signal of ssDNA and RNA molecules and decreases the limit of detection more than 3.5-fold as compared to conventional molecular beacon approaches. This cleavage reaction is highly specific to its target molecules, and no detection of other highly related B-coronaviruses was observed in the presence of complex RNA mixtures. In addition, the FokI-assisted reaction has a high multiplexing potential, as the combined detection of different viral RNAs, including different SARS-CoV-2 variants, was achieved in the presence of multiple combinations of fluorophores and sensing oligonucleotides. When combined with isothermal rolling circle amplification technologies, FokI-assisted digestion reduced the detection time of SARS-CoV-2 in COVID-19-positive human samples with adequate sensitivity and specificity compared to conventional reverse transcription polymerase chain reaction approaches, highlighting the potential of FokI-assisted signal amplification as a valuable sensing mechanism for the detection of human pathogens.
Asunto(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , ADN , Digestión , Humanos , Técnicas de Amplificación de Ácido Nucleico , Oligonucleótidos , ARN Viral/genética , SARS-CoV-2/genética , Sensibilidad y EspecificidadRESUMEN
Cyclic vomiting syndrome is a benign, chronic, functional gastrointestinal pathology that manifests clinically with intense nausea and vomiting interspersed with asymptomatic periods. Its diagnosis is made according to the Rome IV criteria, which require the presence of at least 2 episodes of vomiting in the past 6 months or 3 or more episodes in the past year, with the corresponding exclusion of secondary causes that can explain the vomiting. We present the case of a 44-year-old man who consulted for intermittent nausea and vomiting of 1 year evolution with hydroelectrolytic repercussion and multiple emergency consultations. The diagnosis of cyclic vomiting syndrome was made and treatment with amitriptyline was started due to its neuromodulatory effect to prevent the recurrence of episodes. After 6 months of establishing it, the patient is asymptomatic.
Asunto(s)
Náusea , Vómitos , Masculino , Humanos , Adulto , Vómitos/etiología , Amitriptilina/uso terapéuticoRESUMEN
Zika virus (ZIKV) is a neurotropic flavivirus that causes several diseases including birth defects such as microcephaly. Intrinsic immunity is known to be a frontline defense against viruses through host anti-viral restriction factors. Limited knowledge is available on intrinsic immunity against ZIKV in brains. Amyloid precursor protein (APP) is predominantly expressed in brains and implicated in the pathogenesis of Alzheimer's diseases. We have found that ZIKV interacts with APP, and viral infection increases APP expression via enhancing protein stability. Moreover, we identified the viral peptide, HGSQHSGMIVNDTGHETDENRAKVEITPNSPRAEATLGGFGSLGL, which is capable of en-hancing APP expression. We observed that aging brain tissues with APP had protective effects on ZIKV infection by reducing the availability of the viruses. Also, knockdown of APP expression or blocking ZIKV-APP interactions enhanced ZIKV replication in human neural progenitor/stem cells. Finally, intracranial infection of ZIKV in APP-null neonatal mice resulted in higher mortality and viral yields. Taken together, these findings suggest that APP is a restriction factor that protects against ZIKV by serving as a decoy receptor, and plays a protective role in ZIKV-mediated brain injuries.
Asunto(s)
Precursor de Proteína beta-Amiloide/biosíntesis , Encéfalo/metabolismo , Regulación de la Expresión Génica , Replicación Viral , Infección por el Virus Zika/metabolismo , Virus Zika/fisiología , Precursor de Proteína beta-Amiloide/genética , Animales , Encéfalo/patología , Encéfalo/virología , Humanos , Ratones , Ratones Noqueados , Células-Madre Neurales/metabolismo , Células-Madre Neurales/patología , Células-Madre Neurales/virología , Infección por el Virus Zika/genéticaRESUMEN
The World Health Organization declared coronavirus disease-2019 (COVID-19) a global pandemic in March 2020. Since then, there are more than 34 million cases of COVID-19 leading to more than 1 million deaths worldwide. Numerous studies suggest that celiac disease (CeD), a chronic immune-mediated gastrointestinal condition triggered by gluten, is associated with an increased risk of respiratory infections.1-3 However, how it relates to the risk of COVID-19 is unknown. To address this gap, we conducted a cross-sectional study to evaluate whether patients with self-reported CeD are at an increased risk of contracting COVID-19.
Asunto(s)
COVID-19/epidemiología , Enfermedad Celíaca/epidemiología , Adulto , Estudios de Casos y Controles , Enfermedad Celíaca/dietoterapia , Enfermedad Celíaca/fisiopatología , Dieta Sin Gluten , Femenino , Humanos , Masculino , Oportunidad Relativa , Factores de Riesgo , SARS-CoV-2 , Encuestas y CuestionariosRESUMEN
The aim of this study is to present the first nationwide microbiological and epidemiological study of invasive group A Streptococcus (iGAS) disease in Spain. One thousand eight hundred ninety-three iGAS isolates were analyzed over 2007-2019. emm typing was performed by sequencing the gene's variable 5' end, exotoxin genes were identified by PCR, and antimicrobial susceptibility explored via the E test and disk diffusion. Five hundred twenty-three isolates were associated with sepsis, 292 with cellulitis, 232 with scarlet fever, 153 with pneumonia, 141 with streptococcal toxic shock syndrome, and 94 with necrotizing fasciitis. The most prevalent emm types were emm1 (449/1893 isolates), emm89 (210/1893), emm3 (208/1893), emm4 (150/1893), emm12 (112/1893) emm6 (107/1893), emm87 (89/1893), emm28 (88/1893), emm75 (78/1893), emm77 (78/1893), emm11 (58/1893), and emm22 (35/1893). emm1, emm3, emm4, and emm6 were the predominant types affecting children (mostly respiratory infections), while emm11, emm77, and emm89 prevailed in the elderly (mostly skin infections). Each emm type was associated with one or more exotoxin gene (spe, sme, and ssa) profiles. speA was detected in 660 isolates, speB in 1829, speC in 1014, speF in 1826, speG in 1651, speJ in 716, speH in 331, smeZ in 720, and ssa in 512. Isolates with speA were associated with the most severe infections. Penicillin susceptibility was universal. Two hundred twenty-four isolates were resistant to tetracycline, 169 to erythromycin, and 81 to clindamycin. Tetracycline, erythromycin, and clindamycin resistance rates declined over the study period. The above information could serve as the basis for continued surveillance efforts designed to control disease cause by this bacterium.
Asunto(s)
Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Niño , Preescolar , Eritromicina/farmacología , Exotoxinas/genética , Exotoxinas/metabolismo , Femenino , Humanos , Lactante , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Penicilinas/farmacología , España/epidemiología , Infecciones Estreptocócicas/epidemiología , Streptococcus pyogenes/clasificación , Streptococcus pyogenes/efectos de los fármacos , Streptococcus pyogenes/genética , Adulto JovenRESUMEN
Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death.
Asunto(s)
Apoptosis , Diferenciación Celular , Cromatina/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Células Mieloides/metabolismo , Acetilación , Animales , Células Cultivadas , Cromatina/genética , Epigénesis Genética , Humanos , Ratones Endogámicos C57BL , Ratones Noqueados , Células Mieloides/citología , Procesamiento Proteico-Postraduccional , Transcripción GenéticaRESUMEN
Loss of 5-hydroxymethylcytosine (5hmC) has been associated with mutations of the ten-eleven translocation (TET) enzymes in several types of cancer. However, tumors with wild-type TET genes can also display low 5hmC levels, suggesting that other mechanisms involved in gene regulation might be implicated in the decline of this epigenetic mark. Here we show that DNA hypermethylation and loss of DNA hydroxymethylation, as well as a marked reduction of activating histone marks in the TET3 gene, impair TET3 expression and lead to a genome-wide reduction in 5hmC levels in glioma samples and cancer cell lines. Epigenetic drugs increased expression of TET3 in glioblastoma cells and ectopic overexpression of TET3 impaired in vitro cell growth and markedly reduced tumor formation in immunodeficient mice models. TET3 overexpression partially restored the genome-wide patterns of 5hmC characteristic of control brain samples in glioblastoma cell lines, while elevated TET3 mRNA levels were correlated with better prognosis in glioma samples. Our results suggest that epigenetic repression of TET3 might promote glioblastoma tumorigenesis through the genome-wide alteration of 5hmC.
Asunto(s)
Neoplasias Encefálicas/genética , Carcinogénesis/genética , Dioxigenasas/genética , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Glioblastoma/genética , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Animales , Biopsia , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Metilación de ADN , Regulación hacia Abajo , Glioblastoma/mortalidad , Glioblastoma/patología , Código de Histonas/genética , Humanos , Ratones , Pronóstico , ARN Mensajero/metabolismo , Análisis de Supervivencia , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Aberrant DNA hypermethylation is a hallmark of cancer although the underlying molecular mechanisms are still poorly understood. To study the possible role of 5-hydroxymethylcytosine (5hmC) in this process we analyzed the global and locus-specific genome-wide levels of 5hmC and 5-methylcytosine (5mC) in human primary samples from 12 non-tumoral brains and 53 gliomas. We found that the levels of 5hmC identified in non-tumoral samples were significantly reduced in gliomas. Strikingly, hypo-hydroxymethylation at 4627 (9.3%) CpG sites was associated with aberrant DNA hypermethylation and was strongly enriched in CpG island shores. The DNA regions containing these CpG sites were enriched in H3K4me2 and presented a different genuine chromatin signature to that characteristic of the genes classically aberrantly hypermethylated in cancer. As this 5mC gain is inversely correlated with loss of 5hmC and has not been identified with classical sodium bisulfite-based technologies, we conclude that our data identifies a novel 5hmC-dependent type of aberrant DNA hypermethylation in glioma.
Asunto(s)
5-Metilcitosina/análogos & derivados , Biomarcadores de Tumor/genética , Metilación de ADN , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Genoma Humano , Glioma/patología , 5-Metilcitosina/metabolismo , Estudios de Casos y Controles , Islas de CpG , Glioma/genética , Glioma/metabolismo , HumanosRESUMEN
BACKGROUND: Evidence indicates that low-grade inflammation can alter gastrointestinal motor and sensory function and might contribute to the genesis of symptoms in IBS. OBJECTIVE: To examine relationships between IBS, disease antibodies and cytokine titers in celiac patients and a control group. MATERIALS AND METHODS: IBS, CD activity and serum levels of IL-6, IL-8 and IL12/23p40 were determined in celiac patients and controls. RESULTS: 123 celiac patients were included, 89% were female. 59% demonstrated disease activity and 32% met IBS criteria. Prevalence of IBS was not different between patients who adhered or did not adhere to GFD as well as between patients with or without positive antibodies. Celiac patients had increased levels of IL-6, IL-8 and IL12/23p40 as compared to controls. Higher levels of cytokines were found in celiac patients with IBS than in those without IBS. No difference in levels of cytokines was found between patients with and without CD positive antibodies. A significant negative correlation between the mental component of QoL and IL-6 and IL12/23p40 levels was found, but not with IL-8. CONCLUSION: Higher levels of inflammatory cytokines were found in CD patients with IBS than in either those without IBS or controls, indicating that IBS symptoms are associated with an increase in the inflammatory response and a decrease in quality of life of CD patients. These differences in cytokine levels were not related to CD antibodies status suggesting that IBS, in CD, is related to a different inflammatory process than that which is relevant to CD.
Asunto(s)
Anticuerpos/sangre , Enfermedad Celíaca/complicaciones , Enfermedad Celíaca/inmunología , Interleucina-12/sangre , Interleucina-6/sangre , Interleucina-8/sangre , Síndrome del Colon Irritable/sangre , Síndrome del Colon Irritable/complicaciones , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
CONTEXT: Heliopsis longipes (A. Gray) Blake (Asteraceae), a plant native to Mexico, is used in traditional medicine as analgesic and microbicide. The main component in the H. longipes ethanolic extract (HLEE) is affinin, as determined by HPLC/UV-visible and NMR measurement. To date, there is no documented evidence on the spermicidal activity of this extract. OBJECTIVE: The objective of this study was to assess in vitro the effectiveness of HLEE as spermicide. MATERIALS AND METHODS: The spermicidal activity of HLEE was evaluated by the Sander-Cramer assay. Spermatozoa were incubated for 20 s with HLEE in concentrations ranging from 75 to 2000 µg/mL to determine the minimum effective concentration (MEC) value. The 50% effective concentration (EC50) of HLEE was estimated by assaying serial dilutions from the MEC. Additionally, sperms were incubated with 125, 250, or 500 µg/mL of HLEE to evaluate the viability and the integrity of sperm membrane. Lipid peroxidation was assessed by the thiobarbituric acid reactive substances assay. RESULTS: HLEE caused an inhibition of 100% in spermatozoa motility at a MEC value of 2000 µg/mL; the EC50 value was 125 µg/mL. Additionally, exposure to HLEE at 125, 250, or 500 µg/mL for 30 min decreased sperm viability to 27%, 8%, and 2% of the control value, respectively, and significantly increased the percentage of sperms with structurally disorganized membrane. HLEE also increased significantly the level of lipid peroxidation in sperms with respect to controls. DISCUSSION AND CONCLUSION: The results demonstrate the spermicidal activity of HLEE in vitro and suggest that this action is caused by oxidative damage and alterations in the spermatozoal membrane.
Asunto(s)
Asteraceae/química , Etanol/química , Extractos Vegetales/farmacología , Motilidad Espermática/efectos de los fármacos , Espermicidas/farmacología , Espermatozoides/efectos de los fármacos , Animales , Membrana Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Peroxidación de Lípido/efectos de los fármacos , Masculino , Ratones , Extractos Vegetales/aislamiento & purificación , Raíces de Plantas/química , Espermicidas/aislamiento & purificación , Espermatozoides/metabolismo , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
BACKGROUND: The "fitness" of an infectious pathogen is defined as the ability of the pathogen to survive, reproduce, be transmitted, and cause disease. The fitness of multidrug-resistant tuberculosis (MDRTB) relative to drug-susceptible tuberculosis is cited as one of the most important determinants of MDRTB spread and epidemic size. To estimate the relative fitness of drug-resistant tuberculosis cases, we compared the incidence of tuberculosis disease among the household contacts of MDRTB index patients to that among the contacts of drug-susceptible index patients. METHODS AND FINDINGS: This 3-y (2010-2013) prospective cohort household follow-up study in South Lima and Callao, Peru, measured the incidence of tuberculosis disease among 1,055 household contacts of 213 MDRTB index cases and 2,362 household contacts of 487 drug-susceptible index cases. A total of 35/1,055 (3.3%) household contacts of 213 MDRTB index cases developed tuberculosis disease, while 114/2,362 (4.8%) household contacts of 487 drug-susceptible index patients developed tuberculosis disease. The total follow-up time for drug-susceptible tuberculosis contacts was 2,620 person-years, while the total follow-up time for MDRTB contacts was 1,425 person-years. Using multivariate Cox regression to adjust for confounding variables including contact HIV status, contact age, socio-economic status, and index case sputum smear grade, the hazard ratio for tuberculosis disease among MDRTB household contacts was found to be half that for drug-susceptible contacts (hazard ratio 0.56, 95% CI 0.34-0.90, p = 0.017). The inference of transmission in this study was limited by the lack of genotyping data for household contacts. Capturing incident disease only among household contacts may also limit the extrapolation of these findings to the community setting. CONCLUSIONS: The low relative fitness of MDRTB estimated by this study improves the chances of controlling drug-resistant tuberculosis. However, fitter multidrug-resistant strains that emerge over time may make this increasingly difficult.
Asunto(s)
Antituberculosos/uso terapéutico , Composición Familiar , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/transmisión , Tuberculosis/tratamiento farmacológico , Tuberculosis/transmisión , Femenino , Humanos , Incidencia , Masculino , Perú/epidemiología , Estudios Prospectivos , Tuberculosis/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/epidemiologíaRESUMEN
DNA topology plays a crucial role in all living cells. In prokaryotes, negative supercoiling is required to initiate replication and either negative or positive supercoiling assists decatenation. The role of DNA knots, however, remains a mystery. Knots are very harmful for cells if not removed efficiently, but DNA molecules become knotted in vivo. If knots are deleterious, why then does DNA become knotted? Here, we used classical genetics, high-resolution 2D agarose gel electrophoresis and atomic force microscopy to show that topoisomerase IV (Topo IV), one of the two type-II DNA topoisomerases in bacteria, is responsible for the knotting and unknotting of sister duplexes during DNA replication. We propose that when progression of the replication forks is impaired, sister duplexes become loosely intertwined. Under these conditions, Topo IV inadvertently makes the strand passages that lead to the formation of knots and removes them later on to allow their correct segregation.
Asunto(s)
Replicación del ADN , Topoisomerasa de ADN IV/metabolismo , ADN Bacteriano/ultraestructura , ADN Bacteriano/química , ADN Encadenado/química , Microscopía de Fuerza Atómica , Conformación de Ácido NucleicoRESUMEN
Fluorides are contaminants that occur frequently and, generally, naturally in groundwater, affecting countries that depend on these waters for irrigation and human consumption. Chronic exposure to fluorides generates various health effects; therefore, this research was based on education and risk communication to contribute to the resolution of the problem of fluoride exposure in the population. The objective was to develop the capacity to design risk communication programs for personnel involved in the response and management of environmental health risks, with emphasis on fluoride exposure. An online pilot training course on risk communication and fluoride exposure was designed and implemented. For the analysis of the risk perception and knowledge of the participants, before and after the course, a questionnaire was applied and a focus group was conducted. In addition, the participants carried out a series of activities and designed a risk communication program to assess the degree to which the capacity to develop risk communication programs was achieved. To improve the pilot course, two satisfaction surveys were designed and implemented, and a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis was conducted. The results showed an increase in the level of knowledge and changes in the participants' perception; regarding the ability to design risk communication programs, two participants were able to design them excellently. Previous experience, motivation, commitment to learn and the feedback provided during the course influenced the development of this ability.
Los fluoruros son contaminantes presentes con frecuencia y generalmente de forma natural en aguas subterráneas, y afectan a países que dependen de estas aguas para el riego y el consumo humano. La exposición crónica a fluoruros genera diversos efectos a la salud; por lo anterior, esta investigación se basó en la educación y la comunicación de riesgos para contribuir a la resolución del problema de exposición a fluoruros en la población. El objetivo fue desarrollar la capacidad de diseñar programas de comunicación de riesgos del personal involucrado en la respuesta y manejo de los riesgos ambientales para la salud, con énfasis en la exposición a fluoruros. Se diseñó e implementó un curso piloto de formación en línea sobre comunicación de riesgos y exposición a fluoruros. Para el análisis de la percepción de riesgos y conocimientos de los participantes, antes y después del curso, se aplicó un cuestionario y se llevó a cabo un grupo focal. Además, los asistentes realizaron una serie de actividades y diseñaron un programa de comunicación de riesgos con el que se valoró el grado en que se alcanzó la capacidad de desarrollar programas de comunicación de riesgos. Para mejorar el curso piloto se diseñaron y aplicaron dos encuestas de satisfacción y se realizó un análisis FODA (Fortalezas, Oportunidades, Debilidades, Amenazas). Los resultados mostraron un incremento en el nivel de conocimientos y cambios en la percepción de los participantes; en cuanto a la capacidad de diseñar programas de comunicación de riesgos, dos participantes lograron diseñarlo de manera excelente. La experiencia previa, la motivación, el compromiso para aprender y la retroalimentación brindada durante el curso, influyeron en el desarrollo de esta capacidad.
Os fluoretos são contaminantes que ocorrem com frequência e, geralmente, de forma natural nas águas subterrâneas, afetando os países que dependem dessas águas para irrigação e consumo humano. A exposição crônica aos fluoretos gera vários efeitos à saúde; portanto, esta pesquisa baseou-se na educação e na comunicação de riscos para contribuir com a solução do problema da exposição ao fluoreto na população. O objetivo foi desenvolver a capacidade de elaborar programas de comunicação de risco para o pessoal envolvido na resposta e no gerenciamento de riscos ambientais à saúde, com ênfase na exposição à fluoretos. Foi elaborado e implementado um curso piloto de treinamento online sobre comunicação de riscos e exposição. Para a análise da percepção de risco e do conhecimento dos participantes antes e depois do curso, foi aplicado um questionário e aplicado um grupo de foco. Além disso, os participantes realizaram uma série de atividades e elaboraram um programa de comunicação de riscos para avaliar até que ponto a capacidade de desenvolver programas de comunicação de riscos foi alcançada. Para aprimorar o curso piloto, foram duas pesquisas de satisfação foram desenvolvidas e implementadas e uma análise FOFA (Forças, Oportunidades, Fraquezas e Ameaças) foi aplicada. Os resultados mostraram um aumento no nível de conhecimento e mudanças nas percepções dos participantes; em termos da capacidade de elaborar programas de comunicação de riscos, dois participantes conseguiram elaborar excelentes programas de comunicação de riscos. A experiência prévia, a motivação, o compromisso com o aprendizado e o feedback fornecido durante o curso influenciaram o desenvolvimento dessa capacidade.
Asunto(s)
Fluoruros , Humanos , Fluoruros/efectos adversos , Niño , Exposición a Riesgos Ambientales/prevención & control , Exposición a Riesgos Ambientales/efectos adversos , Encuestas y Cuestionarios , Femenino , Conocimientos, Actitudes y Práctica en Salud , Masculino , Comunicación , Adulto , Proyectos Piloto , Educación en Salud/métodos , Medición de Riesgo , BrasilRESUMEN
Aging involves the deterioration of organismal function, leading to the emergence of multiple pathologies. Environmental stimuli, including lifestyle, can influence the trajectory of this process and may be used as tools in the pursuit of healthy aging. To evaluate the role of epigenetic mechanisms in this context, we have generated bulk tissue and single cell multi-omic maps of the male mouse dorsal hippocampus in young and old animals exposed to environmental stimulation in the form of enriched environments. We present a molecular atlas of the aging process, highlighting two distinct axes, related to inflammation and to the dysregulation of mRNA metabolism, at the functional RNA and protein level. Additionally, we report the alteration of heterochromatin domains, including the loss of bivalent chromatin and the uncovering of a heterochromatin-switch phenomenon whereby constitutive heterochromatin loss is partially mitigated through gains in facultative heterochromatin. Notably, we observed the multi-omic reversal of a great number of aging-associated alterations in the context of environmental enrichment, which was particularly linked to glial and oligodendrocyte pathways. In conclusion, our work describes the epigenomic landscape of environmental stimulation in the context of aging and reveals how lifestyle intervention can lead to the multi-layered reversal of aging-associated decline.
Asunto(s)
Envejecimiento , Epigénesis Genética , Heterocromatina , Hipocampo , Animales , Hipocampo/metabolismo , Envejecimiento/genética , Masculino , Ratones , Heterocromatina/metabolismo , Heterocromatina/genética , Ratones Endogámicos C57BL , Ambiente , ARN Mensajero/metabolismo , ARN Mensajero/genética , Análisis de la Célula IndividualRESUMEN
BACKGROUND: Array-CGH represents a comprehensive tool to discover genomic disease alterations that could potentially be applied to body fluids. In this report, we aimed at applying array-CGH to urinary samples to characterize bladder cancer. METHODS: Urinary DNA from bladder cancer patients and controls were hybridized on 44K oligonucleotide arrays. Validation analyses of identified regions and candidates included fluorescent in situ hybridization (FISH) and immunohistochemistry in an independent set of bladder tumors spotted on custom-made tissue arrays (n = 181). RESULTS: Quality control of array-CGH provided high reproducibility in dilution experiments and when comparing reference pools. The most frequent genomic alterations (minimal recurrent regions) among bladder cancer urinary specimens included gains at 1q and 5p, and losses at 10p and 11p. Supervised hierarchical clustering identified the gain at 1q23.3-q24.1 significantly correlated to stage (p = 0.011), and grade (p = 0.002). The amplification and overexpression of Prefoldin (PFND2), a selected candidate mapping to 1q23.3-q24.1, correlated to increasing stage and tumor grade by means of custom-designed and optimized FISH (p = 0.013 and p = 0.023, respectively), and immunohistochemistry (p ≤0.0005 and p = 0.011, respectively), in an independent set of bladder tumors included in tissue arrays. Moreover, PFND2 overexpression was significantly associated with poor disease-specific survival (p ≤0.0005). PFND2 was amplified and overexpressed in bladder tumors belonging to patients providing urinary specimens where 1q23.3q24.1 amplification was detected by array-CGH. CONCLUSIONS: Genomic profiles of urinary DNA mirrowed bladder tumors. Molecular profiling of urinary DNA using array-CGH contributed to further characterize genomic alterations involved in bladder cancer progression. PFND2 was identified as a tumor stratification and clinical outcome prognostic biomarker for bladder cancer patients.