192 research outputs found

    Comparative Genomics Analysis of a New Exiguobacterium Strain from Salar de Huasco Reveals a Repertoire of Stress-Related Genes and Arsenic Resistance

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    Indexación: Web of Science; Scopus.The Atacama Desert hosts diverse ecosystems including salt flats and shallow Andean lakes. Several heavy metals are found in the Atacama Desert, and microorganisms growing in this environment show varying levels of resistance/tolerance to copper, tellurium, and arsenic, among others. Herein, we report the genome sequence and comparative genomic analysis of a new Exiguobacterium strain, sp. SH31, isolated from an altiplanic shallow athalassohaline lake. Exiguobacterium sp. SH31 belongs to the phylogenetic Group II and its closest relative is Exiguobacterium sp. S17, isolated from the Argentinian Altiplano (95% average nucleotide identity). Strain SH31 encodes a wide repertoire of proteins required for cadmium, copper, mercury, tellurium, chromium, and arsenic resistance. Of the 34 Exiguobacterium genomes that were inspected, only isolates SH31 and S17 encode the arsenic efflux pump Acr3. Strain SH31 was able to grow in up to 10 mM arsenite and 100 mM arsenate, indicating that it is arsenic resistant. Further, expression of the ars operon and acr3 was strongly induced in response to both toxics, suggesting that the arsenic efflux pump Acr3 mediates arsenic resistance in Exiguobacterium sp. SH31.http://journal.frontiersin.org/article/10.3389/fmicb.2017.00456/ful

    Understanding the limits to ethnic change: lessons from Uganda's “lost counties”

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    The historically constructed nature of ethnicity has become a widely accepted paradigm in the social sciences. Scholars have especially have focused on the ways modern states have been able to create and change ethnic identities, with perhaps the strongest case studies coming from colonial Africa, where the gap between strong states and weak societies has been most apparent. I suggest, however, that in order to better understand how and when ethnic change occurs it is important to examine case studies where state-directed ethnic change has failed. To rectify this oversight I examine the case of the “lost counties” of Uganda, which were transferred from the Bunyoro kingdom to the Buganda kingdom at the onset of colonial rule. I show that British attempts to assimilate the Banyoro residents in two of the lost counties were an unmitigated failure, while attempts in the other five counties were successful. I claim that the reason for these differing outcomes lies in the status of the two lost counties as part of the historic Bunyoro homeland, whereas the other five counties were both geographically and symbolically peripheral to Bunyoro. The evidence here thus suggests that varying ethnic attachments to territory can lead to differing outcomes in situations of state-directed assimilation and ethnic change

    The novel choline kinase inhibitor ICL-CCIC-0019 reprograms cellular metabolism and inhibits cancer cell growth.

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    The glycerophospholipid phosphatidylcholine is the most abundant phospholipid species of eukaryotic membranes and essential for structural integrity and signaling function of cell membranes required for cancer cell growth. Inhibition of choline kinase alpha (CHKA), the first committed step to phosphatidylcholine synthesis, by the selective small-molecule ICL-CCIC-0019, potently suppressed growth of a panel of 60 cancer cell lines with median GI50 of 1.12 μM and inhibited tumor xenograft growth in mice. ICL-CCIC-0019 decreased phosphocholine levels and the fraction of labeled choline in lipids, and induced G1 arrest, endoplasmic reticulum stress and apoptosis. Changes in phosphocholine cellular levels following treatment could be detected non-invasively in tumor xenografts by [18F]-fluoromethyl-[1,2–2H4]-choline positron emission tomography. Herein, we reveal a previously unappreciated effect of choline metabolism on mitochondria function. Comparative metabolomics demonstrated that phosphatidylcholine pathway inhibition leads to a metabolically stressed phenotype analogous to mitochondria toxin treatment but without reactive oxygen species activation. Drug treatment decreased mitochondria function with associated reduction of citrate synthase expression and AMPK activation. Glucose and acetate uptake were increased in an attempt to overcome the metabolic stress. This study indicates that choline pathway pharmacological inhibition critically affects the metabolic function of the cell beyond reduced synthesis of phospholipids

    Do Loading Path and Specimen Thickness Affect the Brittle Compressive Failure of Ice?

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    Compressive experiments were performed on square (160 mm × 160 mm) prismatic specimens of columnar-grained, S2 freshwater ice, biaxially loaded across the columns at −10°C. The work focused on brittle behavior, achieved by deforming the specimens at an applied strain rate of 4.5 ± 1.2 × 10 3s 1 in the direction of shortening. The results show that the specimen thickness (25–150 mm) has no detectable effect on the terminal failure strength of the ice. Likewise, the strength of the ice when loaded under proportional loading, where the minor stress varies during the test, was similar to that when loaded under a constant minor stress, implying that terminal failure depends only on the stress state and not on the path taken

    Does the Normal Stress Parallel to the Sliding Plane Affect the Friction of Ice upon Ice?

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    Sliding experiments were performed at –10 degrees C on smooth surfaces of freshwater columnar-grained S2 ice sliding against itself at a velocity of 8X10 –4 ms –1, with the purpose of examining whether normal stress parallel to the sliding plane affects frictional resistance. This component of the stress tensor was varied (0.20–1.83 MPa) using a loading system operated under biaxial compression, by orienting the sliding plane at two different angles, 26 degrees and 64 degrees, with respect to the principal loading direction. Under these conditions, no evidence was found to indicate that the normal stress in the direction of sliding affects the friction coefficient

    Impacto del Covid-19 en comunidades vecinas de la gran minería y recomendaciones para su manejo

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    Teniendo en consideración la pandemia del COVID-19 y las dificultades que ha enfrentado nuestro territorio en un contexto mundial de incertidumbre de salud, económica y comunitaria, se ha planteado este trabajo que busca describir y analizar algunas variables de salud pública en población general e indicadores económicos relacionados con las comunas mineras más afectadas por la pandemia de la COVID-19 el año 2020, para finalmente formular recomendaciones de gestión para la industria. Mediante un análisis descriptivo y un análisis multicriterio con abordaje territorial, se realiza un análisis de brechas entre lo observado y lo que está recomendado, planteando esta situación como un problema multivariado con potenciales abordajes desde diferentes aristas. Se plantea la situación actual de manejo de comunidades en minería, el contexto socioeconómico de las regiones de Antofagasta y Atacama, principales focos mineros de Chile. Luego se describe el manejo de COVID-19 en minería, en el mundo y en Chile. Se describen los principales organismos reguladores y orientadores de política de manejo de pandemia (OMS, UE, CDC) y el abordaje que ha tenido la industria minera en el país desde las faenas y hacia sus comunidades. Se analizan las brechas de aportes y medidas en la gran industria minera con información pública disponible. Se analizan los riesgos de las comunas de las regiones de Antofagasta y Atacama, proponiendo un enfoque territorial para ese análisis, utilizando unidades comunales. Se propone una implementación con abordaje territorial a nivel comunitario y de trabajadores, tomando como unidades a las familias a partir del trabajador, planteando una organización de la minera ad hoc con coordinación interna. Se concluye que, en términos generales, se han tomado medidas dentro de la industria y realizado aportes fuera de la industria minera, no existiendo sinergias dentro de la industria o aportes a su interior, o medidas fuera de ella hacia comunidades. Se observa una desarticulación entre las medidas que se han adoptado dentro de la industria y lo que se aporta hacia fuera de la industria. En resumen, se visualizan dos ejes centrales de trabajo y mejora en las medidas adoptadas en la minería chilena, el primero es interno a nivel de trabajadores, y el segundo a nivel de comunidades. Ambos enfrentándolos con herramientas numéricas de trabajo y un enfoque territorial.Versión original del auto

    The novel choline kinase inhibitor ICL-CCIC-0019 reprograms cellular metabolism and inhibits cancer cell growth

    Get PDF
    The glycerophospholipid phosphatidylcholine is the most abundant phospholipid species of eukaryotic membranes and essential for structural integrity and signaling function of cell membranes required for cancer cell growth. Inhibition of choline kinase alpha (CHKA), the first committed step to phosphatidylcholine synthesis, by the selective small-molecule ICL-CCIC-0019, potently suppressed growth of a panel of 60 cancer cell lines with median GI50 of 1.12 μM and inhibited tumor xenograft growth in mice. ICL-CCIC-0019 decreased phosphocholine levels and the fraction of labeled choline in lipids, and induced G1 arrest, endoplasmic reticulum stress and apoptosis. Changes in phosphocholine cellular levels following treatment could be detected non-invasively in tumor xenografts by [18F]-fluoromethyl-[1,2–2H4]-choline positron emission tomography. Herein, we reveal a previously unappreciated effect of choline metabolism on mitochondria function. Comparative metabolomics demonstrated that phosphatidylcholine pathway inhibition leads to a metabolically stressed phenotype analogous to mitochondria toxin treatment but without reactive oxygen species activation. Drug treatment decreased mitochondria function with associated reduction of citrate synthase expression and AMPK activation. Glucose and acetate uptake were increased in an attempt to overcome the metabolic stress. This study indicates that choline pathway pharmacological inhibition critically affects the metabolic function of the cell beyond reduced synthesis of phospholipids
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