Obtención y purificación de extractos de la enzima monóxido de carbono deshidrogenasa de Oligotropha carboxidovorans (cepa OM 5) con actividad de oxidación de monóxido de carbono detectable electroquímicamente por medio de un microelectrodo de platin

Extracts of the enzyme carbon monoxide dehydrogenase capable to oxidize carbon monoxide to CO2 were obtained from the carboxidotrophic bacteria Oligotropha carboxidovorans OM5 cultivated under aerobic conditions in a mineral medium saturated with CO. The extracts were obtained disrupting cells by sonication and purification by molecular size-exclusion chromatography and ion-exchange chromatography. The enzymatic activity of the extracts was measured using methylene blue as an artificial electronic acceptor in the oxidation of the CO to CO2. Crude and purified extracts showed enzymatic activity detectable by spectrophotometry. The maximum grade of purification obtained was 200 times and specific enzymatic activities were achieved in the range from 0.01 to 2.0 mU/mg of protein. Electrochemical assays using a platinum microelectrode and methylene blue as an electronic mediator showed an increase of the anodic current when the substrate carbon monoxide was added to the cell that contained the enzymatic extract. These results encourage the construction of an electrochemical biosensor for the detection of carbon monoxide using enzymatic extracts obtained from carboxidotrophic bacteria.Se obtuvieron extractos crudos y purificados de la enzima monóxido de carbono deshidrogenasa capaces de oxidar monóxido de carbono a CO2, a partir de cultivos de la bacteria carboxidotrofa Oligotropha carboxidovorans (cepa OM5) cultivadas aeróbicamente em un medio mineral saturado con CO. Los extractos crudos se obtuvieron mediante la ruptura de las células por sonicación y se purificaron por cromatografía de exclusión molecular y cromatografía de intercambio iónico. La actividad enzimática de los extractos se midió utilizando azul de metileno como aceptor electrónico artificial en la oxidación del CO a CO2. Se obtuvieron extractos crudos y purificados con actividad enzimática detectable por medio de espectrofotometría. El grado máximo de purificación obtenido fue de 200 veces y se lograron actividades enzimáticas específicas en el rango de 0.01 a 2.0 mU/mg de proteína. Ensayos electroquímicos usando un microelectrodo deplatino y azul de metileno como mediador electrónico, mostraron un aumento de la corriente anódica cuando se adicionó el sustrato monóxido de carbono a la celda que contenía el extracto enzimático. Estos resultados permiten alentar la construcción de un biosensor electroquímico para la detección de monóxido de carbono, utilizando extractos enzimáticos obtenidos a partir de bacterias carboxidotrofas

Seismic constraints from a Mars impact experiment using InSight and Perseverance

NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed1,2 and uncrewed3,4 spacecraft, and on the Moon during the Apollo era5, but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance’s entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance–amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy)

Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation.

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars

Seismic constraints from a Mars impact experiment using InSight and Perseverance

NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed1,2 and uncrewed3,4 spacecraft, and on the Moon during the Apollo era5, but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance’s entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance–amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy)

Obtención y purificación de extractos de la enzima monóxido de carbono deshidrogenasa de Oligotropha carboxidovorans (cepa OM 5) con actividad de oxidación de monóxido de carbono detectable electroquímicamente por medio de un microelectrodo de platin

Se obtuvieron extractos crudos y purificados de la enzima monóxido de carbono deshidrogenasa capaces de oxidar monóxido de carbono a CO2, a partir de cultivos de la bacteria carboxidotrofa Oligotropha carboxidovorans (cepa OM5) cultivadas aeróbicamente em un medio mineral saturado con CO. Los extractos crudos se obtuvieron mediante la ruptura de las células por sonicación y se purificaron por cromatografía de exclusión molecular y cromatografía de intercambio iónico. La actividad enzimática de los extractos se midió utilizando azul de metileno como aceptor electrónico artificial en la oxidación del CO a CO2. Se obtuvieron extractos crudos y purificados con actividad enzimática detectable por medio de espectrofotometría. El grado máximo de purificación obtenido fue de 200 veces y se lograron actividades enzimáticas específicas en el rango de 0.01 a 2.0 mU/mg de proteína. Ensayos electroquímicos usando un microelectrodo deplatino y azul de metileno como mediador electrónico, mostraron un aumento de la corriente anódica cuando se adicionó el sustrato monóxido de carbono a la celda que contenía el extracto enzimático. Estos resultados permiten alentar la construcción de un biosensor electroquímico para la detección de monóxido de carbono, utilizando extractos enzimáticos obtenidos a partir de bacterias carboxidotrofas.Extracts of the enzyme carbon monoxide dehydrogenase capable to oxidize carbon monoxide to CO2 were obtained from the carboxidotrophic bacteria Oligotropha carboxidovorans OM5 cultivated under aerobic conditions in a mineral medium saturated with CO. The extracts were obtained disrupting cells by sonication and purification by molecular size-exclusion chromatography and ion-exchange chromatography. The enzymatic activity of the extracts was measured using methylene blue as an artificial electronic acceptor in the oxidation of the CO to CO2. Crude and purified extracts showed enzymatic activity detectable by spectrophotometry. The maximum grade of purification obtained was 200 times and specific enzymatic activities were achieved in the range from 0.01 to 2.0 mU/mg of protein. Electrochemical assays using a platinum microelectrode and methylene blue as an electronic mediator showed an increase of the anodic current when the substrate carbon monoxide was added to the cell that contained the enzymatic extract. These results encourage the construction of an electrochemical biosensor for the detection of carbon monoxide using enzymatic extracts obtained from carboxidotrophic bacteria

Mutagenicity evaluation caused by heavy metals found in Cauca river water in the city of Cali, Colombia

Se evaluó la mutagenicidad del agua del río Cauca debida a la presencia de metales pesados en la zona urbana de la Ciudad de Santiago de Cali, a partir de muestras tomadas en la temporada seca y lluviosa en el año 2013. Los metales se extrajeron pasando el agua por la resina Amberlite XAD-16. Las concentraciones de los metales pesados se midieron por absorción atómica y la mutagenicidad se evaluó por medio del test de Ames, con las cepas TA98 y TA100 de Salmonella typhimurium con y sin activador enzimático S9. Los resultados mostraron índices de mutagenicidad (IM) positivos (IM > 2,0) para muestras colectadas en temporada lluviosa en tres de los cinco puntos evaluados: puente El Hormiguero (IM = 3,6), desembocadura del Canal Colector Sur (IM = 2,9) y desembocadura del río Cali (IM = 2,7), todos con la cepa TA98 sin S9. Estos sitios presentaron a su vez las mayores concentraciones totales de metales pesados en sus extractos. El análisis de la variación espacio-temporal del índice mutagénico se realizó haciendo un análisis de varianza multifactorial del IM. Los resultados encontrados indican que la época de muestreo contribuye significativamente a la variabilidad del IM , mientras que los puntos de muestreo noThe mutagenicity of the Cauca River water due to the presence of heavy metals was evaluated in the urban area of the city of Santiago de Cali, from samples taken during the rainy and dry season of 2013. The metals were extracted from water samples using the resin Amberlite XAD-16. The concentrations of heavy metals were measured by atomic absorption and mutagenicity was evaluated by the Ames test, using the TA98 and TA100 strains of Salmonella typhimurium with and without the S9 enzymatic activator. The results showed mutagenicity indices (MI > 2.0) in three of the five points evaluated: El Hormiguero Bridge (MI = 3.6), the mouth of southern collector channel (MI = 2.9) and the mouth of Cali River (MI = 2.7), all with strain TA98 without S9. These sampling points in turn presented the highest total concentrations of heavy metals in the extracts. The determination and analysis of spatio-temporal variation of the mutagenic effects obtained was done by conducting multifactorial variance analysis of MI, finding that the effect of sampling season contributes significantly to the variability of MI unlike the sampling point

Seismic constraints from a Mars impact experiment using InSight and Perseverance

NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed(1,2) and uncrewed(3,4) spacecraft, and on the Moon during the Apollo eras(5), but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance's entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance-amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy).ISSN:2397-336

Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars