Genome-wide screening reveals metabolic regulation of stop-codon readthrough by cyclic AMP.

Translational fidelity is critical for microbial fitness, survival and stress responses. Much remains unknown about the genetic and environmental control of translational fidelity and its single-cell heterogeneity. In this study, we used a high-throughput fluorescence-based assay to screen a knock-out library of Escherichia coli and identified over 20 genes critical for stop-codon readthrough. Most of these identified genes were not previously known to affect translational fidelity. Intriguingly, we show that several genes controlling metabolism, including cyaA and crp, enhance stop-codon readthrough. CyaA catalyzes the synthesis of cyclic adenosine monophosphate (cAMP). Combining RNA sequencing, metabolomics and biochemical analyses, we show that deleting cyaA impairs amino acid catabolism and production of ATP, thus repressing the transcription of rRNAs and tRNAs to decrease readthrough. Single-cell analyses further show that cAMP is a major driver of heterogeneity in stop-codon readthrough and rRNA expression. Our results highlight that carbon metabolism is tightly coupled with stop-codon readthrough.

TENT2, TUT4, and TUT7 selectively regulate miRNA sequence and abundance.

TENTs generate miRNA isoforms by 3' tailing. However, little is known about how tailing regulates miRNA function. Here, we generate isogenic HEK293T cell lines in which TENT2, TUT4 and TUT7 are knocked out individually or in combination. Together with rescue experiments, we characterize TENT-specific effects by deep sequencing, Northern blot and in vitro assays. We find that 3' tailing is not random but highly specific. In addition to its known adenylation, TENT2 contributes to guanylation and uridylation on mature miRNAs. TUT4 uridylates most miRNAs whereas TUT7 is dispensable. Removing adenylation has a marginal impact on miRNA levels. By contrast, abolishing uridylation leads to dysregulation of a set of miRNAs. Besides let-7, miR-181b and miR-222 are negatively regulated by TUT4/7 via distinct mechanisms while the miR-888 cluster is upregulated specifically by TUT7. Our results uncover the selective actions of TENTs in generating 3' isomiRs and pave the way to investigate their functions.

Heterogeneous Flagellar Expression in Single Salmonella Cells Promotes Diversity in Antibiotic Tolerance.

Phenotypic heterogeneity among single cells in a genetically identical population leads to diverse environmental adaptation. The human and animal pathogen Salmonella enterica serovar Typhimurium exhibits heterogeneous expression of virulence genes, including flagellar and Salmonella pathogenicity island (SPI) genes. Little is known about how the differential expression of flagellar genes among single cells affects bacterial adaptation to stresses. Here, we have developed a triple-fluorescence reporter to simultaneously monitor the expression of flagellar and SPI-1 pathways. We show that the two pathways cross talk at the single-cell level. Intriguingly, cells expressing flagella (fliC-ON) exhibit decreased tolerance to antibiotics compared to fliC-OFF cells. Such variation depends on TolC-dependent efflux pumps. We further show that fliC-ON cells contain higher intracellular proton concentrations. This suggests that the assembly and rotation of flagella consume the proton motive force and decrease the efflux activity, resulting in antibiotic sensitivity. Such a trade-off between motility and efflux highlights a novel mechanism of antibiotic tolerance. IMPORTANCE Antibiotic resistance and tolerance pose a severe threat to human health. How bacterial pathogens acquire antibiotic tolerance is not clear. Here, we show that the human and animal pathogen Salmonella divides its population into subgroups that are different in their abilities to tolerate antibiotic treatments. In a Salmonella population that is genetically identical, some cells express flagella to move toward nutrients, while other cells do not express flagella. Interestingly, we show that Salmonella cells that do not express flagella are more tolerant to antibiotics. We have further determined the mechanism underlying such diverse responses to antibiotics. Flagellar motility uses cellular energy stored in the form of proton motive force and makes cells less efficient in pumping out toxic molecules such as antibiotics. The overall bacterial population therefore gains benefits from such diversity to quickly adapt to different environmental conditions.

Hábito y calidad del desayuno; su efecto en el rendimiento académico de estudiantes de técnico de nivel superior en enfermería / Habit and quality of breakfast: its effect on academic performance of senior technician students in nursing / Effet de l'habitude et la qualité du petit déjeuner sur les résultats scolaires des étudiants Techniciens Supérieurs en Soins Infirmiers

Resumen Objetivo: Estudiar la relación existente entre el desayuno y el rendimiento académico en los estudiantes de Técnico de Nivel Superior en Enfermería (TNSE) de la Universidad Adventista de Chile (UnACh). Material y Métodos: Estudio cuantitativo, descriptivo y transversal, en un universo de 39 estudiantes que cursaron las asignaturas troncales durante los años 2016-2017 y a los que se aplicó un cuestionario de frecuencia de consumo y hábitos alimenticios. Asimismo, se recogieron datos sociodemográficos y calificaciones académicas de dichos estudiantes. El rendimiento académico para este trabajo se definió como el promedio, por estudiante, de calificaciones en las asignaturas de Anatomía y Fisiología, Enfermería en Urgencias y Principios de Farmacología. Resultados: Un 73.5% de los encuestados consume cereales al menos 4 días/semana y 54.5% consume frutas al desayuno 3 días o menos por semana. El consumo de leche y sus derivados más de 3 días/semana se eleva a 61.7%. Se destaca el consumo de pan (66.7%), plátano (46.2%) y leche (30.4%), lo cual coincide con las preferencias de consumo de una familia chilena. Sumado a esto, el 53.8 % de los estudiantes encuestados no toman desayuno en casa, manifestando como principal causa la falta de tiempo (57.1%). En cuanto al rendimiento académico se encontró que el rango de la media de calificaciones varía de 53.9 a 61.0 (escala 1-100 puntos), con altas tasas de reprobación de 1 o más veces en las asignaturas cursadas. Conclusión: No se encontró una relación significativa entre calidad del desayuno y la media de calificaciones en las diferentes asignaturas, sin embargo, no es posible descartar totalmente que la calidad del desayuno o su omisión no altere el rendimiento académico de los estudiantes, que impactan en el desarrollo de los procesos cognitivos.

Abstract Objective: Study the relationship between breakfast and academic performance in Senior Technician Students in Nursing, from the Adventist University of Chile (UnACh). Materials and methods: A cross-sectional, descriptive and quantitative research was carried out in a universe of 39 students who took the core subjects during the years 2016 and 2017, and to whom a consumption frequency questionnaire and eating habits was applied. Likewise, sociodemographic data and academic qualifications of these students were collected. The academic performance for this work was defined as the grade average per student in the subjects of Anatomy, Physiology, Emergency Department Nursing and Pharmacology. Results: 73.5% of respondents consume cereals at least 4 days a week and 54.5% eat fruits for breakfast 3 days or less a week. The consumption of milk and dairy products more than 3 days a week rises to 61.7%. The consumption of bread (66.7%), banana (46.2%) and milk (30.4%) stands out, which coincides with the consumption preferences of a Chilean family. In addition, 53.8% of the surveyed students do not eat breakfast at home, stating lack of time as the main cause (57.1%). Regarding academic performance, it was found that the range of the average grades differs from 53.9 to 61.0 (scale 1-100 points) with high failure rates of one or more times in the subjects taken. Conclusion: No significant relationship was found between the quality of breakfast and the mean of grades in the different subjects. However, it is not possible to rule out that the quality of breakfast or its omission does not affect the academic performance of the students, which has an impact on the development of cognitive processes.

Resumo Objetivo: Estudar a relação entre o desjejum e o desempenho acadêmico em estudantes Técnicos de Enfermagem de Nível Superior (TNSE) da Universidade Adventista do Chile (UnACh). Material e Métodos: Estudo quantitativo, descritivo e transversal, em um universo de 39 alunos que cursaram as disciplinas centrais durante os anos de 2016 a 2017 e aos quais foi aplicado um questionário de frequência de consumo e hábitos alimentares. Da mesma forma, foram coletados dados sociodemográficos e habilitações literárias dos referidos alunos. O desempenho acadêmico para este trabalho foi definido como a média, por aluno, das notas nas disciplinas de Anatomia e Fisiologia, Enfermagem de Emergência e Princípios de Farmacologia. Resultados: 73,5% dos pesquisados consomem cereais pelo menos 4 dias / semana e 54,5% consomem frutas no café da manhã 3 dias ou menos na semana. O consumo de leite e seus derivados mais de 3 dias / semana sobe para 61,7%. Destaca-se o consumo de pão (66,7%), banana (46,2%) e leite (30,4%), que coincide com as preferências de consumo de uma família chilena. Somado a isso, 53,8% dos alunos pesquisados não tomam café da manhã em casa, citando a falta de tempo como principal causa (57,1%). Em relação ao desempenho escolar, constatou-se que a faixa de notas médias varia de 53,9 a 61,0 (escala de 1 a 100 pontos), com altas taxas de reprovação de 1 ou mais vezes nas disciplinas cursadas. Conclusão: Não foi encontrada relação significativa entre a qualidade do café da manhã e as notas médias nas diferentes disciplinas, porém, não é possível descartar totalmente que a qualidade do café da manhã ou sua omissão não altera o desempenho escolar dos alunos, o que impacta o desenvolvimento de processos cognitivos.

Résumé Objectif: Étudier la relation entre le petit déjeuner et les résultats scolaires des étudiants du programme de Technicien Supérieur en Soins Infirmiers (TNSE)de l'Université adventiste du Chili (UnACh). Matériel et méthodes: Étude quantitative, descriptive et transversale, auprès d'un univers de 39 étudiants qui ont suivi les matières de bases au cours des années 2016-2017 et ont répondu à un questionnaire sur leurs fréquences de consommation et leurs habitudes alimentaires. Des données sociodémographiques et les notes de ces étudiants ont aussi été recueillies. Pour ce travail, les résultats académiques des étudiants ont été définis par la moyenne des notes obtenues dans les matières Anatomie et physiologie, Soins infirmiers d'urgence et Principes de pharmacologie. Résultats: Au petit déjeuner, 73,5 % des personnes interrogées ont consommé des céréales au moins 4 jours par semaine et 54,5 % ont consommé des fruits 3 jours ou moins par semaine. La consommation de lait et de ses dérivés plus de 3 jours par semaine s'élève à 61,7 %. La consommation de pain (66,7%), de bananes (46,2%) et de lait (30,4%) est prédominante, ce qui correspond aux préférences de consommation des familles chiliennes. 53,8 % des étudiants interrogés ne prennent pas leur petit déjeuner à la maison ; ils indiquent que cela est principalement par manque de temps (57,1 %). En ce qui concerne les résultats scolaires, il a été constaté que la fourchette des moyennes varie de 53,9 à 61,0 (échelle de 1 à 100 points), avec un fort pourcentage d'échec une ou plusieurs fois dans les matières. Conclusion: Aucune relation significative n'a été trouvée entre la qualité du petit déjeuner et la moyenne des notes dans les différentes matières ; cependant, il n'est pas possible d'exclure totalement que la qualité du petit déjeuner, ou son omission, puisse altérer les résultats scolaires des étudiants, du fait de l'impact sur le développement des processus cognitifs.

AGO-bound mature miRNAs are oligouridylated by TUTs and subsequently degraded by DIS3L2.

MicroRNAs (miRNAs) associated with Argonaute proteins (AGOs) regulate gene expression in mammals. miRNA 3' ends are subject to frequent sequence modifications, which have been proposed to affect miRNA stability. However, the underlying mechanism is not well understood. Here, by genetic and biochemical studies as well as deep sequencing analyses, we find that AGO mutations disrupting miRNA 3' binding are sufficient to trigger extensive miRNA 3' modifications in HEK293T cells and in cancer patients. Comparing these modifications in TUT4, TUT7 and DIS3L2 knockout cells, we find that TUT7 is more robust than TUT4 in oligouridylating mature miRNAs, which in turn leads to their degradation by the DIS3L2 exonuclease. Our findings indicate a decay machinery removing AGO-associated miRNAs with an exposed 3' end. A set of endogenous miRNAs including miR-7, miR-222 and miR-769 are targeted by this machinery presumably due to target-directed miRNA degradation.

3' Uridylation Confers miRNAs with Non-canonical Target Repertoires.

Many microRNAs (miRNAs) exist alongside abundant miRNA isoforms (isomiRs), most of which arise from post-maturation sequence modifications such as 3' uridylation. However, the ways in which these sequence modifications affect miRNA function remain poorly understood. Here, using human miR-27a in cell lines as a model, we discovered that a nonfunctional target site unable to base-pair extensively with the miRNA seed sequence can regain function when an upstream adenosine is able to base-pair with a post-transcriptionally added uridine in the miR-27a tail. This tail-U-mediated repression (TUMR) is abolished in cells lacking the uridylation enzymes TUT4 and TUT7, indicating that uridylation alters miRNA function by modulating target recognition. We identified a set of non-canonical targets in human cells that are specifically regulated by uridylated miR-27a. We provide evidence that TUMR expands the targets of other endogenous miRNAs. Our study reveals a function of uridylated isomiRs in regulating non-canonical miRNA targets.

Absceso de psoas / Psoas abscess

El absceso de psoas es una enfermedad relativamente rara. Muchos casos presentan características clínicas atípicas. El absceso de psoas puede ser primario en pacientes inmunodeprimidos o secundario a infecciones gastrointestinales y genitourinarias. En los países no desarrollados, la mayoría de estos pueden ser de etiología tuberculosa. Una alta sospecha clínica, una buena historia clínica y estudios de imagen, pueden ser útiles en el diagnóstico y tratamiento de la enfermedad. El tratamiento temprano con antibióticos, drenaje guiado o cirugía abierta es necesario debido a su alta morbimortalidad. Se reporta el caso de un paciente varón de 57 años con historia de Diabetes mellitus (DM) de 20 años de evolución, quien refiere dolor en región lumbar izquierda asociada a aumento de volumen y fiebre intermitente, por lo que se hospitaliza, detectándose un absceso de psoas izquierdo, el cual es drenado por cirugía abierta con abordaje extra-peritoneal, presentando evolución favorable.

Psoas abscess is a relatively rare disease. Many cases present atypical clinical features. Psoas abscess may be primary in immunosuppressed patients or secondary to gastrointestinal and genitourinary infections. In non-developed countries most of these can be of tuberculous etiology. A high clinical suspicion, a good clinical history and imaging studies can be useful in diagnosing the disease. Early treatment with antibiotics, guided drainage or open surgery is necessary due to its high morbidity and mortality. It's reported the case of a male patient of 57 years with a history of diabetes mellitus (DM) of 20 years of evolution, who referred pain in the left lumbar region associated with increased volume and intermittent fever, so he is hospitalized, detecting an extensive left psoas abscess which is drained by open surgery with extraperitoneal approach, showing favorable evolution.

Effects of negative pressure wound therapy on cellular energetics in fibroblasts grown in a provisional wound (fibrin) matrix.

Negative pressure wound therapy (NPWT) using reticulated open cell foam dressing (ROCF) is effective for treatment of recalcitrant wounds; however, the effects of this therapy on cellular metabolism remain to be elucidated. The effect of two different subatmospheric pressure applications on the cell energetics of human fibroblasts grown in a 3D fibrin matrix was studied using two different pressure-manifolding materials, an ROCF or gauze under suction (GUS). It was found that levels of cytochrome c oxidase, energy charge, and adenosine triphosphate/adenosine diphosphate were significantly increased following the application of NPWT using ROCF vs. GUS (p<0.05). Increases in these parameters likely reflect an improved energetic status. In addition, levels of transforming growth factor-beta and platelet-derived growth factor (alpha and beta isoforms) were significantly increased (80 and 53%, respectively; p<0.05) over static control cultures following treatment with NPWT using ROCF but not following GUS. These growth factors are known to be important during wound healing. Clearly, both the material used as the dressing to manifold the subatmospheric pressure and the pressure used have a dramatic effect on cellular response.

Tension-band wiring for olecranon fractures: analysis of risk factors for failure.

Thirty-seven consecutive olecranon fractures treated with tension-band wiring were evaluated at a mean follow-up of 4 years. There was no or mild pain in 33 cases, mean elbow extension was 7 degrees , and mean elbow flexion was 131 degrees . According to the Mayo Elbow Performance Score, the results were graded as good or excellent in 32 cases (86%). Most patients had mild residual upper extremity disability (mean Disabilities of the Arm, Shoulder and Hand score, 18 points). In 10 patients, degenerative changes developed. Arthritic changes were significantly associated with elbow instability (P = .014) and length of follow-up (P = .031) and were more common in the presence of associated radial head or coronoid fractures (P = .06). Hardware removal was required in 17 cases. Tension-band wiring provides satisfactory results in a high percentage of olecranon fractures. However, the outcome may be compromised in the presence of elbow instability and associated fractures of the radial head and coronoid.

Carcinoma de vejiga: cuadro clínico-patológico / Bladder carcinoma: I square clinical-pathological

El presente estudio tuvo como finalidad identificar el cuadro clínico - patológico de 42 pacientes con carcinoma de vejiga evaluados en el Hospital Belén, Trujillo, Perú, desde 1966 hasta 1996. Hubo 31 hombres y 11 mujeres (H:M:2.8:1), con una edad promedio de 63 ñ 12.6 años (límites, 28 a 82 años). Los antecedentes más frecuentes fueron alcoholismo (21.4 or ciento), tabaquismo (9.5 por ciento), exposición a contaminantes químicos (7.1 por ciento), infección crónica del tracto urinario (7.1 por ciento) y cáncer previo a otros órganos (4.8 por ciento). El tiempo promedio de enfermedad fue de 12.4 meses (límites, 1 a 48 meses). Los síntomas más frecuentes fueron hematuria (91.5 por ciento), disuria (76.2 por ciento) y polaquiuria 64.3 por ciento). El signo más común fue masa suprapública palpable (14.3 por ciento). La sensibilidad diagnóstica de la cistografía (n=20), citología urinaria (n=18), citoscopía (n=28) y biopsias cistoscópica (n=28) fue de 95 por ciento, 61 por ciento, 100 por ciento respectivamente. El 47 por ciento de los casos se clasificó en estadio I, 23.8 por ciento en estadio IV, y 28.6 por ciento en estadios II y III. El carcinoma de células transicionales fue el tipo histológico más común (88 por ciento), seguido por el carcinoma epidermoide(7 por ciento), adenocarcinoma (2.4 por ciento) y carcinoma indiferenciado (2.4 por ciento). El 45.2 por ciento de los cánceres fueron moderamente diferenciados (G2), y 4.8, indiferenciados (G4). Ante pacientes con síntomas urológicos inexplicabes y con factores de riesgo presentes es necesario el estudio citoscópico para la detección de tumores vesicales en estadios iniciales.

Peritonitis bacteriana espontánea en pacientes cirróticos alcohólicos / Spontaneous bacterial peritonitis in alcoholic cirrhosis

Se estudia en forma prospectiva un grupo de 30 pacientes cirróticos alcohólicos con ascitis pero sin complicaciones aparentes ingresados al servicio de medicina del Hospital Félix Bulnes entre junio de 1983 y septiembre de 1984. En 4 de estos pscientes (13.3-) se diagnostica la existencia de peritonitis bacteriana espontánea, en base a la presencia en todos de más de 500 células en el líquido ascítico, con más de un 75% de polimorfonucleares y en 3 de ellos por un cultivo positivo a escherichia coli con más de 10**5 por milímitro