Lactate oxidation is linked to energy conservation and to oxygen detoxification via a putative terminal cytochrome oxidase in Methanosarcina acetivorans.

The marine archaeon Methanosarcina acetivorans contains a putative NAD + -independent d-lactate dehydrogenase (D-iLDH/glycolate oxidase) encoded by the MA4631 gene, belonging to the FAD-oxidase C superfamily. Nucleotide sequences similar to MA4631 gene, were identified in other methanogens and Firmicutes with >90 and 35-40% identity, respectively. Therefore, the lactate metabolism in M. acetivorans is reported here. Cells subjected to intermittent pulses of oxygen (air-adapted; AA-Ma cells) consumed lactate only in combination with acetate, increasing methane production and biomass yield. In AA-Ma cells incubated with d-lactate plus [14C]-l-lactate, the radioactive label was found in methane, CO2 and glycogen, indicating that lactate metabolism fed both methanogenesis and gluconeogenesis. Moreover, d-lactate oxidation was coupled to O2-consumption which was sensitive to HQNO; also, AA-Ma cells showed high transcript levels of gene dld and those encoding subunits A (MA1006) and B (MA1007) of a putative cytochrome bd quinol oxidase, compared to anaerobic control cells. An E. coli mutant deficient in dld complemented with the MA4631 gene, grew with d-lactate as carbon source and showed membrane-bound d-lactate:quinone oxidoreductase activity. The product of the MA4631 gene is a FAD-containing monomer showing activity of iLDH with preference to d-lactate. The results suggested that air adapted M. acetivorans is able to co-metabolize lactate and acetate with associated oxygen consumption by triggering the transcription and synthesis of the D-iLDH and a putative cytochrome bd: methanophenazine (quinol) oxidoreductase. Biomass generation and O2 consumption, suggest a potentially new oxygen detoxification mechanism coupled to energy conservation in this methanogen.

Transcriptomic Responses of Rhizobium phaseoli to Root Exudates Reflect Its Capacity to Colonize Maize and Common Bean in an Intercropping System.

Corn and common bean have been cultivated together in Mesoamerica for thousands of years in an intercropping system called "milpa," where the roots are intermingled, favoring the exchange of their microbiota, including symbionts such as rhizobia. In this work, we studied the genomic expression of Rhizobium phaseoli Ch24-10 (by RNA-seq) after a 2-h treatment in the presence of root exudates of maize and bean grown in monoculture and milpa system under hydroponic conditions. In bean exudates, rhizobial genes for nodulation and degradation of aromatic compounds were induced; while in maize, a response of genes for degradation of mucilage and ferulic acid was observed, as well as those for the transport of sugars, dicarboxylic acids and iron. Ch24-10 transcriptomes in milpa resembled those of beans because they both showed high expression of nodulation genes; some genes that were expressed in corn exudates were also induced by the intercropping system, especially those for the degradation of ferulic acid and pectin. Beans grown in milpa system formed nitrogen-fixing nodules similar to monocultured beans; therefore, the presence of maize did not interfere with Rhizobium-bean symbiosis. Genes for the metabolism of sugars and amino acids, flavonoid and phytoalexin tolerance, and a T3SS were expressed in both monocultures and milpa system, which reveals the adaptive capacity of rhizobia to colonize both legumes and cereals. Transcriptional fusions of the putA gene, which participates in proline metabolism, and of a gene encoding a polygalacturonase were used to validate their participation in plant-microbe interactions. We determined the enzymatic activity of carbonic anhydrase whose gene was also overexpressed in response to root exudates.

Preclinical Assessment of a New Polyvalent Antivenom (Inoserp Europe) against Several Species of the Subfamily Viperinae.

The European continent is inhabited by medically important venomous Viperinae snakes. Vipera ammodytes, Vipera berus, and Vipera aspis cause the greatest public health problems in Europe, but there are other equally significant snakes in specific regions of the continent. Immunotherapy is indicated for patients with systemic envenoming, of which there are approximately 4000 annual cases in Europe, and was suggested as an indication for young children and pregnant women, even if they do not have systemic symptoms. In the present study, the safety and venom-neutralizing efficacy of Inoserp Europe-a new F(ab')2 polyvalent antivenom, designed to treat envenoming by snakes in the Eurasian region-were evaluated. In accordance with World Health Organization recommendations, several quality control parameters were applied to evaluate the safety of this antivenom. The venom-neutralizing efficacy of the antivenom was evaluated in mice and the results showed it had appropriate neutralizing potency against the venoms of several species of Vipera, Montivipera, and Macrovipera. Paraspecificity of the antivenom was demonstrated as well, since it neutralized venoms of species not included in the immunization schemes and contains satisfactory levels of total proteins and F(ab')2 fragment concentration. Therefore, this new polyvalent antivenom could be effective in the treatment of snake envenoming in Europe, including Western Russia and Turkey.

Aplicación del reactivo de Neesler en la cuantificación de amonio para las fermentaciones de productos biotecnológicos / Application of Neesler reagent in the ammonium quantification used in the fermentations of biotechnology product

Las sales de amonio se utilizan en las fermentaciones para suplementar las cantidades deficitarias de nitrógeno y estabilizar el pH del medio de cultivo. El ion amonio en exceso, ejerce un efecto perjudicial en el proceso fermentativo ya que inhibe el crecimiento microbiano. Con el objetivo de monitorear y controlar la concentración de amonio durante el proceso de fermentación, se desarrolló un método con el reactivo de Neesler, para la cuantificación de dicho analito. El ensayo se estandarizó mediante: selección del equipo de medición; tiempo de reacción del ensayo y comparación de las sales estándares de amonio. El método se caracterizó con la evaluación de los parámetros: especificidad; linealidad y rango del sistema, límite de cuantificación, exactitud y precisión. El método demostró ser específico. Se establecieron dos sistemas con curvas que fueron lineales en los rangos de cloruro de amonio (2 a 20 µg/mL) y sulfato de amonio (5 a 30 µg/mL). Los límites de cuantificación fueron los puntos inferiores de cada rango de trabajo. El método resultó ser preciso y exacto. Este ensayo se aplicó a muestras de cultivos de levadura y bacterias del género Saccharomyces y Escherichia. coli respectivamente. Se desarrolló un método novedoso en microplaca para la cuantificación y control analítico del amonio. Mediante este método se controla este componente químico fundamental en las fermentaciones, para optimizar el medio de cultivo. Se logra una adecuada expresión de proteínas recombinantes y la obtención de candidatos vacunales para uso clínico(AU)

The ammonium salts are used in fermentations to supplement the deficient amounts of nitrogen and stabilize the pH of the culture medium. The excess ammonium ion exerts a detrimental effect on the fermentation process inhibiting microbial growth. An analytical method based on Neesler reagent was developed for monitoring and controlling the concentration of ammonium during the fermentation process. The test was standardized, by means of the selection of measuring equipment, and the reaction time as well as comparing standards of ammonium salts. The method was characterized with the evaluation of the next parameters: Specificity, Linearity and Range, Quantification Limit, Accuracy and Precision. The method proved to be specific. Two linear curves were defined in the ranges of concentrations of ammonium chloride salt (2-20 µg/ml) and ammonium sulfate salt (5-30 µg/ml). The limits of quantification were the lowest points of each one. The method proved to be accurate and precise. This assay was applied to samples of the yeast culture and bacteria of the genus Saccharomyces and E. coli respectively . A novel method in micro plate for quantification and analytical control of ammonia was developed. T his method is used to control this fundamental chemical component in the fermentations , to optimize the culture medium. Thus, an appropriate expression of recombinant proteins and proper vaccine candidates for clinical use are achieved(AU)

Tratamiento no quirúrgico de colección pancreática en pancreatitis aguda grave: presentación de caso / Non surgical treatment of pancreatic collection in severe acute pancreatitis: case presentation

La pancreatitis aguda es un gran drama abdominal, de gravedad variable, seleccionar el tratamiento apropiado requiere identificación de pacientes conriesgo de complicaciones y muerte, ningún método detecta todos los pacientesque van a desarrollar complicación. La atención varía desde conducta quirúrgicatemprana a tratamiento médico en las Unidades de Cuidados Intensivos cuyoprincipal objetivo es corregir la hipovolemia, y detención o regresión del Síndrome de Respuesta Inflamatoria Sistémica. La atención debe ser por unequipo multidisciplinario. Los antimicrobianos profilácticos han sidocontroversiales; en países en vías de desarrollo con recursos limitados, estaterapéutica puede ser beneficiosa. Se presenta una mujer de 36 años que sufre de pancreatitis aguda grave con colección pancreática, que se le indicó tratamiento médico no intervencionista y antibioprofilaxis teniendo una evolución favorable, con resolución total, la cual estuvo ingresada en la Unidad de Cuidados Intensivas del Hospital General Docente de Placetas en octubre del 2012(AU)

Evaluación de los métodos de la normatividad mexicana para la determinación de nitritos en alimentos infantiles

Se evaluaron los dos métodos para la determinación de nitritos, que solicita la normatividad mexicana, en alimentos infantiles cárnicos con verduras. Se determinó el contenido de nitritos a los alimentos infantiles, materias primas y productos intermedios del proceso de elaboración; en cada corrida analítica se incluyeron un blanco de reactivos y una muestra testigo; además se determinó la sensibilidad, porcentaje de recuperación y precisión de las metodologías. Los resultados en los alimentos infantiles indicaron una importante diferencia en los contenidos de nitritos obtenidos entre las metodologías, debido a la persistente presencia de turbidez en los extractos. Se propusieron diferentes tratamientos físicos para eliminarla, pero únicamente la redujeron; tal turbidez se atribuyó a los hidratos de carbono; las concentraciones de nitritos informadas presentaron una dispersión grande y estuvieron por debajo del límite de cuantificación de ambos métodos, por lo que no es recomendable la aplicación de estas técnicas para alimentos que se sospechan contienen trazas de nitritos.

Evaluation of the methods for the determination of nitrites in baby foods according Mexican legislation. We evaluated the two methods accepted by the Mexican norm for the determination of nitritesin infant meatbased food with vegetables. We determined the content of nitrites in the infant food, raw materials as well as products from the intermediate stages of production. A reagent blank and a reference sample were included at each analytical run. In addition, we determined the sensitivity, recovery percentage and accuracy of each methodology. Infant food results indicated an important difference in the nitrite content determined under each methodology, due to the persistent presence of turbidity in the extracts. Different treatments were proposed to eliminate the turbidity, but these only managed to reduce it. The turbidity was attributed to carbohydrates which disclosed concentration exhibit a wide dispersion and were below the quantifiable limit under both methodologies; therefore it is not recommended to apply these techniques with food suspected to contain traces of nitrites.

[Evaluation of the methods for the determination of nitrites in baby foods according Mexican legislation]. / Evaluación de los métodos de la normatividad mexicana para la determinación de nitritos en alimentos infantiles.

We evaluated the two methods accepted by the Mexican norm for the determination of nitritesin infant meat-based food with vegetables. We determined the content of nitrites in the infant food, raw materials as well as products from the intermediate stages of production. A reagent blank and a reference sample were included at each analytical run. In addition, we determined the sensitivity, recovery percentage and accuracy of each methodology. Infant food results indicated an important difference in the nitrite content determined under each methodology, due to the persistent presence of turbidity in the extracts. Different treatments were proposed to eliminate the turbidity, but these only managed to reduce it. The turbidity was attributed to carbohydrates which disclosed concentration exhibit a wide dispersion and were below the quantifiable limit under both methodologies; therefore it is not recommended to apply these techniques with food suspected to contain traces of nitrites.