The Native 3D Organization of Bacterial Polysomes

SummaryRecent advances have led to insights into the structure of the bacterial ribosome, but little is known about the 3D organization of ribosomes in the context of translating polysomes. We employed cryoelectron tomography and a template-matching approach to map 70S ribosomes in vitrified bacterial translation extracts and in lysates of active E. coli spheroplasts. In these preparations, polysomal arrangements were observed in which neighboring ribosomes are densely packed and exhibit preferred orientations. Analysis of characteristic examples of polysomes reveals a staggered or pseudohelical organization of ribosomes along the mRNA trace, with the transcript being sequestered on the inside, the tRNA entrance sites being accessible, and the polypeptide exit sites facing the cytosol. Modeling of elongating nascent polypeptide chains suggests that this arrangement maximizes the distance between nascent chains on adjacent ribosomes, thereby reducing the probability of intermolecular interactions that would give rise to aggregation and limit productive folding

Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

CryoET shows the configuration of the ephemeral translationally inactive 100S ribosomal dimer

A Bayesian Approach for Estimating the Thinning Corrosion Rate of Steel Heat Exchanger in Hydrodesulfurization Plants

Fuel consumption has been increasing in recent years, especially that of diesel and jet fuel. For this reason, the necessity to build new plants to reduce their sulfur content has arisen. Sometimes, just revamping existing plants is feasible, but determining which pieces of equipment are in the appropriate condition to be reused is also necessary. In order to select the equipment, it is essential to have information about the wall thickness of vessels. Sometimes, the information is limited; consequently, the application of advanced statistical techniques is needed. ,e Bayesian Data Analysis (BDA) used in this study has the goal of determining a more accurate, unobserved thinning rate distribution for existing heat exchangers, taking into consideration all the information available about the thinning rate of the heat exchangers that cool down the effluent of the hydrotreating reactors in Mexican oil refineries. ,e information obtained from BDA was compared with existing shell wall thickness obtaining favorable results

Seroprevalence of bovine viral diarrhea virus (BVDV) in cattle from Sotaquirá, Colombia

Worldwide distributed Bovine Viral Diarrhea Virus (BVDV) represents a high risk of infection in most bovine farms, in which it is associated with gastrointestinal, respiratory, and reproductive diseases. The purpose of this research was to establish the seroprevalence and the main risk factors associated with the presentation of BVDV in the municipality of Sotaquirá, Colombia. Samples were taken from 1000 cattle of Holstein, Ayrshire, Jersey, Normande Gyr and Holstein x Gyr. Epidemiological surveys were implemented, reproductive and management variables were taken into consideration. Indirect ELISA was performed to detect specific antibodies against BVDV using the commercial kit SERELISA® BVD p80 Ab Mono Blocking. The overall seroprevalence of antibodies against BVDV was 42.5% (425/1000), where the Gyr breed (59.1% apparent prevalence (AP); 60.3% real prevalence (PR)) and the age group > 4 years (53.0% PA; 54.4% PR) presented the highest seroprevalences. A significant statistical association was found for the breed, age, management practices evaluated and the presentation of PI3 (p ≤ 0.05). Age group > 4 years, Normande breed, presentation of PI3 and grazing lease were established as risk factors associated with BVDV in the herds. These infections are mainly associated with dairy cattle and herds with many animals, so it is important to consider vaccination plans as a preventive system and follow up on the most common diseases

Perfil microbiológico y sensibilidad a antibióticos de microorganismos aislados de infecciones conjuntivales en el Instituto de Oftalmología Fundación Conde de Valenciana. Reporte del año 2012

ResumenIntroducciónLa conjuntiva es el tejido ocular que se infecta con mayor frecuencia. Los agentes patógenos más frecuentes de la conjuntivitis suelen ser los virus y las bacterias. El uso indiscriminado de antibióticos de amplio espectro para tratar la conjuntivitis ha generado microorganismos resistentes.ObjetivoIdentificar los microorganismos más frecuentes aislados de muestras de origen conjuntival y conocer su susceptibilidad antibiótica.Material y métodosRevisión retrospectiva de cultivos provenientes de raspados conjuntivales obtenidos durante el 2012.ResultadosSe obtuvieron 44 muestras de origen conjuntival. Estas provinieron de 21 varones y 23 mujeres. La mediana (25%, 75%) de la edad fue 62 años (39-68). El cultivo fue positivo en 13 de las muestras obtenidas, identificándose 5 microorganismos diferentes. Staphylococcus epidermidis fue el microorganismo aislado con mayor frecuencia (9 cepas). Todas las cepas de S. epidermidis fueron sensibles a vancomicina, gentamicina, cefotaxima, moxifloxacino y ofloxacino. La mayoría de las cepas de S. epidermidis (6/9) mostraron resistencia a múltiples antibióticos.ConclusionesStaphylococcus epidermidis fue el microorganismo aislado con mayor frecuencia en muestras provenientes de infecciones conjuntivales. Todas las cepas de S. epidermidis fueron sensibles a vancomicina, gentamicina y moxifloxacino y la mayoría de ellas fueron multirresistentes a los antibióticos en evaluación.AbstractIntroductionThe conjunctiva is the tissue of the eye that gets infected with more frequency. The most common pathogens of conjunctivitis are viruses and bacteria. The indiscriminate use of broad-spectrum antibiotics to treat conjunctivitis generated resistant microorganisms.ObjectiveIdentify the most common microorganisms isolated from samples of conjunctival origin and know their antibiotic susceptibility.Material and methodsRetrospective review of culture from conjunctival swabs obtained during 2012.ResultsWe collected 44 samples of conjunctival origin. They came from 21 males and 23 women. The median (25%, 75%) of age was 62 years (39-68). The culture was positive in 13 samples, identifying five different microorganisms. Staphylococcus epidermidis was the most common isolated microorganism (9 strains). All strains of S. epidermidis were sensitive to vancomycin, gentamicin, cefotaxime, ofloxacin and moxifloxacin. The multiple antibiotic resistance was identified in the majority of strains of S. epidermidis (6/9).ConclusionsStaphylococcus epidermidis was the most common isolated microorganism from samples of conjuntival infections. All strains of S. epidermidis were sensitive to vancomycin and moxifloxacin and most of them showed multidrug resistance to antibiotics

Diagnóstico coproparasitológico de fascioliasis en ovinos y caprinos de Boavita, Boyacá (Colombia)

The aim of this study was to establish the prevalence of Fasciola hepatica through coprological analysis and to identify risk factors associated with the presentation of the parasite in sheep and goats in the municipality of Boavita, Boyacá. The study was observational, descriptive, cross-sectional with simple random sampling. Faecal samples were taken from 297 sheep and 337 goats to identify parasite eggs. The general prevalence was 8.0% (51/634), being 9.1% for sheep and 7.1% for goats. The prevalence in sheep was higher in males (14.8%) than in females (8.5%), likewise, sheep less than one year old (9.3%) and Criolla (11.1%) presented the highest prevalence. In goats, the prevalence was higher in females (7.3%) than in males (5.6%), and those less than one year old (10.5%) and the Alpine breed (8%) presented the greater prevalence. No significant statistical association was found between females and males. The Creole breed was established as a risk factor for sheep.El objetivo del estudio fue establecer la prevalencia de Fasciola hepatica mediante análisis coprológico e identificar factores de riesgo asociados a la presentación del parásito en ovinos y caprinos del municipio de Boavita, Boyacá. El estudio fue observacional, descriptivo de corte transversal con muestreo aleatorio simple. Se tomaron muestras de materia fecal a 297 ovinos y 337 caprinos para identificar los huevos del parásito. La prevalencia general fue de 8.0% (51/634), siendo de 9.1% para ovejas y de 7.1% para cabras. La prevalencia en ovinos fue mayor en machos (14.8%) que en hembras (8.5%); asimismo, los ovinos menores a un año (9.3%) y de Criolla (11.1%) presentaron las prevalencias más altas. En las cabras, la prevalencia fue mayor en hembras (7.3%) que en machos (5.6%), y los menores a un año (10.5%) y de la raza Alpina (8%) presentaron las prevalencias más altas. No se encontró asociación estadística significativa entre hembras y machos. La raza Criolla se estableció como factor de riesgo para los ovinos

Actualización sobre los virus que infectan papaya en Argentina

PosterLa papaya Carica papaya se cultiva en las regiones tropicales y subtropicales, y se establece como una alternativa sustentable en el norte de Argentina Con el objetivo de generar conocimientos para aportar al manejo de las virosis que afectan papaya en Argentina, se realizaron evaluaciones en las principales áreas productorasInstituto de Patología VegetalFil: Cabrera Mederos, Dariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Cabrera Mederos, Dariel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Portal, O. Universidad Central “Marta Abreu” de Las Villas. Facultad de Ciencias Agropecuarias. Santa Clara; CubaFil: Acuña, Luis Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Badaracco, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico (CCT) Nordeste; ArgentinaFil: Badaracco, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Rodríguez, E. Instituto de Enseñanza Agropecuaria (IEA) N9; ArgentinaFil: Nickel, A. Instituto de Enseñanza Agropecuaria (IEA) N9; ArgentinaFil: Sáez, S. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; ArgentinaFil: Nome Docampo, Claudia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Nome Docampo, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Debat, Humberto Julio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Debat, Humberto Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Torres, C. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jaramillo, M. Universidad de San Pablo T; ArgentinaFil: Trucco, Veronica Milagros. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Trucco, Veronica Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Ortiz, Claudio Manuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Yuto; ArgentinaFil: Flores, Ceferino Rene. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Yuto; ArgentinaFil: Castellanos Collazo, Onias. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Giolitti, Fabian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Giolitti, Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); Argentin

Noise Contributions in an Inducible Genetic Switch: A Whole-Cell Simulation Study

Stochastic expression of genes produces heterogeneity in clonal populations of bacteria under identical conditions. We analyze and compare the behavior of the inducible lac genetic switch using well-stirred and spatially resolved simulations for Escherichia coli cells modeled under fast and slow-growth conditions. Our new kinetic model describing the switching of the lac operon from one phenotype to the other incorporates parameters obtained from recently published in vivo single-molecule fluorescence experiments along with in vitro rate constants. For the well-stirred system, investigation of the intrinsic noise in the circuit as a function of the inducer concentration and in the presence/absence of the feedback mechanism reveals that the noise peaks near the switching threshold. Applying maximum likelihood estimation, we show that the analytic two-state model of gene expression can be used to extract stochastic rates from the simulation data. The simulations also provide mRNA–protein probability landscapes, which demonstrate that switching is the result of crossing both mRNA and protein thresholds. Using cryoelectron tomography of an E. coli cell and data from proteomics studies, we construct spatial in vivo models of cells and quantify the noise contributions and effects on repressor rebinding due to cell structure and crowding in the cytoplasm. Compared to systems without spatial heterogeneity, the model for the fast-growth cells predicts a slight decrease in the overall noise and an increase in the repressors rebinding rate due to anomalous subdiffusion. The tomograms for E. coli grown under slow-growth conditions identify the positions of the ribosomes and the condensed nucleoid. The smaller slow-growth cells have increased mRNA localization and a larger internal inducer concentration, leading to a significant decrease in the lifetime of the repressor–operator complex and an increase in the frequency of transcriptional bursts

Marine Biodiversity in the Caribbean: Regional Estimates and Distribution Patterns

This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela – Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of different taxa