AISLAMIENTO E IDENTIFICACIÓN DE Lactobacillus spp. (LACTOBACILLACEAE) RESISTENTES A Cd(II) Y As(III) RECUPERADOS DE FERMENTO DE CACAO / Isolation and identification of Lactobacillus spp. (Lactobacillaceae) resistant to Cd(II) and As(III) from fermented cocoa

RESUMEN El objetivo de este estudio fue aislar e identificar a partir de cacao fermentado en Caldas Colombia, bacterias con potencial de aplicación en procesos biotecnológicos, como la detoxificación de cadmio (Cd(II)) y arsénico (As(III)) en el organismo humano. En total se recuperaron 36 aislados de los cuales se recuperaron 11 en presencia de 1,0 mg/L de Cd(II) y 25 en presencia de 0,1 mg/L de As(III). Su identificación molecular determinó que la mayoría de los aislados son del género Lactobacillus. Los ensayos de crecimiento en presencia de diferentes concentraciones de los elementos evaluados permitió determinar que gran parte de los aislamientos presentan resistencia a mayores concentraciones de As(III) (300 mg/L) que de Cd(II) (10 mg/L). En ensayos de tolerancia a la acidez (pH 2,5) se encontró que la cepa tipo Lactobacillus plantarum JCM 1055, junto con los aislamientos nativos L. plantarum A19, A26 y C16, mostraron la mayor tolerancia, por lo que se seleccionaron para evaluar su tolerancia a condiciones de salinidad. Las bacterias evaluadas mostraron crecimiento en concentraciones de hasta 4 g/L de sales biliares. Se concluye que los L. plantarum evaluados en este trabajo tienen un gran potencial para futuros ensayos en los que se busque demostrar la disminución de la bioaccesibilidad de Cd(II) y As(III) en condiciones in vitro del sistema digestivo humano debido a su resistencia a altas concentraciones de estos elementos y su tolerancia a condiciones de acidez y salinidad. Esto, junto con el reconocido potencial probiótico que tienen estos microorganismos, permitirá a futuro su uso en procesos biológicos de mitigación de Cd(II) y As(III).

ABSTRACT The aim of this study was to isolate and identify from fermented cocoa in Caldas Colombia, bacteria with potential application in biotechnological processes such as detoxification of cadmium (Cd(II)) and arsenic (As(III)) in the human organism. In total, 36 isolates were obtained, from which 11 were recovered in the presence of 1.0 mg/L of Cd(II) and 25 in presence of 0.1 mg/L of As(III). Molecular identification showed most isolates belong to the genera Lactobacillus. Minimum inhibitory concentration assays, in presence of different concentrations of the elements, allowed to determine that the majority of isolates have resistance to higher concentration of As(III) (300 mg/L) than Cd(II) (10 mg/L). Acidity tolerance assays at pH 2.5 showed that type strain Lactobacillus plantarum JCM 1055, and native isolates L. plantarum A19, A26, and C16, presented the highest tolerance, thus they were selected to evaluate their tolerance to salinity conditions. The evaluated bacteria could grow in bile salts up to 4 g/L. It is concluded that the evaluated L. plantarum have great potential to be used in assays in which bioaccessibility of Cd(II) and As(III) is diminished under in vitro conditions of the human digestive system, due to its resistance to high concentrations of the elements and tolerance to acidic and high bile salt conditions. These facts, together with the recognized probiotic potential of these microorganisms, may allow their future use in biological processes to mitigate Cd(II) and As(III).

Assessment of mining activity on arsenic contamination in surface water and sediments in southwestern area of Santurbán paramo, Colombia.

The current emphasis of developing countries on policies that favor the intensification of mining exploitation as the main source of incomes, has generated negative consequences for ecosystems and rural communities, mainly due to the release of highly toxic elements into the environment. This study was carried out to evaluate the effect of the Vetas-California gold mining district on As distribution in stream sediments and surface water samples from Suratá River, located in the southwestern area of Santurbán paramo, Colombia. With this aim, samples distributed along the high Suratá River basin in areas near and far from mining areas were selected. Samples were chemically characterized. The As mobility, enrichment and sources were evaluated using sequential and single extractions, enrichment factor (EF), geoaccumulation index (Igeo), and hierarchical cluster analysis (HCA). The results highlight high As content (reaching up to 484 mg/kg) in stream sediment sampled near the gold mining district. For both sediment and water, the relative As content along the Suratá River exceeded the background content by 220 and 64.9 times, respectively. From the single-stage extractions performed, the reducible fractions found in As(NaOH) and As(HCl) were higher in all cases, meaning a high level of mobility and lixiviation of the As content in water samples by changes in pH and redox potentials. The correlations estimated using Spearman coefficients show that most of the bioavailable fraction of As(Exch) is related to main sediment constituents such as S, Fe2O3, SiO2, and Al2O3 and the relative As content. Calculation of the enrichment factor (EF) confirms high enrichments around active sites of gold mining such as the municipalities of Vetas, California and Matanza with EF values of 285, 204, and 133, respectively. In addition, the Igeo values suggest moderate to strong As pollution due to the high Igeo found at the major mining effect points. The findings from this study are valuable for providing effective management options for risk prevention and control of the persistent As accumulation in Santurbán paramo.

The P-type ATPase CtpF is a plasma membrane transporter mediating calcium efflux in Mycobacterium tuberculosis cells.

Among the 12 P-type ATPases encoded by the genome of Mycobacterium tuberculosis (Mtb), CtpF responds to the greatest number of stress conditions, including oxidative stress, hypoxia, and infection. CtpF is the mycobacterial homolog of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) of higher eukaryotes. Its expression is regulated by the global regulator of latency, DosR. However, the role that CtpF plays in the mycobacterial plasma membrane remains unknown. In this study, different functional analyses showed that CtpF is associated with calcium pumping from mycobacterial cells. Specifically, Mtb CtpF expression in Mycobacterium smegmatis cells prevents Ca2+ accumulation compared with wild type (WT) cells. In addition, plasma membrane vesicles from recombinant membranes, in which the direction of ion transport is inverted, accumulate more Ca2+ compared with vesicles obtained from the WT strain. This findings support the hypothesis that CtpF contributes to calcium efflux from mycobacterial cells. Accordingly, Mtb cells defective in ctpF (MtbΔctpF) accumulate more Ca2+ compared with WT cells, while the Ca2+-dependent ATPase activity is significantly lower in the mutant cells. Interestingly, the deletion of ctpF in Mtb impairs the tolerance of the bacteria to oxidative and nitrosative stress. Overall, our results indicate that CtpF is associated with calcium pumping from mycobacterial cells and the response to oxidative stress.

Validation of an HPLC Method for Determination of Bisphenol-A Migration from Baby Feeding Bottles.

A simple and economic high-performance liquid chromatography (HPLC-UV-Vis) analytical method was validated for the quantitation of specific Bisphenol-A migration from baby feeding bottles. Overall and specific migration assays were done with different food simulating matrices using the filling method. Good linearity was obtained over the concentration range of 0.01-0.6 mg/kg. The limit of detection (LOD) and limit of quantification (LOQ) were 0.004 and 0.010 mg/kg, respectively. The repeatability of the method (%RSD, n=10) was between 89.5 and 99.0%, while recovery ranged from 83.2 to 98.4%. The method was applied to specific migration assays from baby feeding bottles purchased from different plastic producers in Colombia. The results show that, in a first migration assay, Bisphenol-A was not detectable in all samples. In a second migration test, Bisphenol-A concentrations were higher than the most restricted limit (0.05 mg/kg) with ethanol 95% and isooctane as food simulants.

Metal and metalloid immobilization by microbiologically induced carbonates precipitation.

The industrialization and growth of human population has increased the release and accumulation of metals and metalloids in the environment. Bioaccumulation and exposure to these elements have been associated with different types of diseases and cancer, thus looking for alternatives that decrease their bioavailability in the environment is crucial. Microbiologically induced carbonates precipitation (MICP) has been proposed as a potential bioremediation method to immobilize contaminating metals and metalloids. Studies published to date have mainly used ureolytic bacteria, reporting metal(loid)s removal percentages up to 100% for some toxic elements, thus demonstrating the effectiveness of this treatment. Various genera of bacteria, particularly Gram-positive, have been reported with MICP abilities. More recently, fungi have also been proposed as a viable alternative for the removal of these toxic elements by carbonate precipitation. This mini-review presents updated information about the main studies carried out to date using different types of microorganisms that perform MICP to decrease the environmental bioavailability of toxic metals and metalloids through the formation of metallic carbonates.

Ensayo de migración global en empaques para alimentos: evaluación de patrones internos alternativos / Overall migration test in food packaging: Evaluation of alternative internal standards / Ensaio de migração global em embalagens de alimentos: avaliação de padrões internos alternativos

Resumen En el ensayo de migración global para empaques plásticos destinados a alimentos grasos se emplea triheptadecanoato de glicerilo (GTM) como patrón interno para la cuantificación de los ésteres metílicos de ácidos grasos (FAMEs) por cromatografía de gases. En este trabajo se evaluaron 3-fenil propanoato de etilo (EFP) y ácido tetradecanóico (AM) como patrones internos alternativos. El uso de AM presentó comportamiento lineal (r > 0,99 y %Sb < 5%), buena precisión intermedia (HORRATr % 0,9) y exactitud (%R % 100,6%). En contraste, la evaluación del EFP, demostró que este no es un patrón interno adecuado para la cuantificación de FAMEs. De otra parte, se evaluó estadísticamente que no hay diferencias significativas en el cálculo de la migración global a partir de FAMEs cuantificados usando como patrón interno GTM o AM, mientras que el uso de EFP sí presenta diferencias significativas.

Abstract In the global migration test for plastic packaging intended for fatty foods, glyceryl triheptadecanoate (GTM) is used as the internal standard for the quantification of fatty acid methyl esters (FAMEs) by gas chromatography. In this work, ethyl 3-phenyl propanoate (EFP) and tetradecanoic acid (AM) were evaluated as alternative internal standards The use of AM presented linear behavior (r > 0.99 and %Sb < 5%), good intermediate precision (HORRATr % 0.9), and accuracy (%R % 100.6%). In contrast, the evaluation of EFP demonstrated that this is not an adequate internal standard for the quantification of FAMEs In addition, it was statistically evaluated that there are no significant differences in the calculation of the global migration from FAMEs quantified using either GTM or AM as internal standards, but the use of EFP presents significant differences.

Resumo No ensaio de migração global para embalagens plásticas destinadas aos alimentos gordurosos, é usado o triheptadecanoato de glicerina (GTM) como padrão interno para a quantificação dos ésteres metílicos de ácidos gordos (FAMEs) mediante cromatografia em fase gasosa. Neste papel foram avaliados 3-fenil propanoato de etilo (EFP) e ácido tetradecanóico (AM) como padrões internos alternativos O (AM) apresentou comportamento linear (r > 0,99 e %Sb < 5%), boa precisão intermédia (HORRATr % 0,9) e precisão (%R % 100,6%). Em contraste, a avaliação do (EFP), mostrou que este não é um padrão interno adequado para a quantificação de FAMEs Por outro lado, uma avaliação estatística indicou que não há diferenças significativas no cálculo da migração global de FAMEs quantificadas utilizando como padrão interno GTM ou AM, em contrapartida o uso do EFP apresenta diferenças significativas.

Environmental occurrence of arsenic in Colombia: a review.

The international literature on the presence of arsenic (As) in Latin America does not disclose the true magnitude of the presence of As in Colombia. In this paper, we summarize the literature on As occurrence in Colombia. The data reveal that As is present in matrices such as soil, sediments and water and in the food chain. Some of the As concentrations exceed the limits specified by national and international regulations. Arsenic higher concentrations are associated with mining regions (e.g., soils, up to 148 mg/kg; sediments, up to 1400 mg/kg) and agricultural areas (e.g., vegetables, up to 5.40 mg/kg; irrigation water, up to 255 µg/L), and underscore the potential human and environmental risks associated with the presence of As in the country. This review highlights the importance of focusing research on understanding the occurrence, origin and distribution of As in Colombia to better understand its environmental and public health impact.

DESARROLLO DE MÉTODOS DE ANÁLISIS POR INYECCIÓN EN FLUJO A PARTIR DE PROCEDIMIENTOS CLÁSICOS: Determinación de Pb en agua / DEVELOPMENT OF FLOW INJECTION ANALYSIS METHODS BY CLASSICAL PROCEDURES: Determination of Pb in water / DESENVOLVIMENTO DE MÉTODOS DE ANÁLISE POR INJEÇÃO EM FLUXO A PARTIR DE PROCEDIMENTOS CLÁSSICOS: determinação de Pb em água

El análisis químico día a día se acerca más a la automatización, buscando satisfacer las necesidades actuales de resultados rápidos y confiables. Los sistemas de análisis en flujo (FIA - Flow Injection Analysis) son una de las formas de aproximarse a la automatización. En este artículo se presentan los pasos necesarios para implementar una metodología FIA, para la determinación de Pb(II) en agua, partiendo de la revisión de los procedimientos clásicos y describiendo detalladamente los pasos necesarios para implementar la técnica de análisis en flujo. El trabajo produjo un método de análisis de Pb en agua que usa ditizona disuelta en isopropanol (agente cromogénico), en presencia de bromuro de cetiltrimetil amonio (CTAB), para solubilizar en agua el complejo, cuyas características más sobresalientes fueron: volumen de inyección de muestra de 81,7 µL, velocidad de flujo de 8,0 mL/min, tiempo de toma de espectros 1,4 s e intervalo lineal de 1,0 a 40 mg L-1.

Chemical analysis has evolved towards automation to satisfy the current requirements: fast analysis and certainty in the results. Flow injection analysis (FIA) is a way to reach automation. This work presents the necessary steps to obtain an optimized FIA methodology for the determination of Pb(II) in water by classic methods. The result was a FIA method to determinate Pb with dithizone (chromogenic agent) dissolved in iso-propyl alcohol, using cethyltrimethylammonium bromide (CTAB) to solubilize the complex. The main characteristics of the method were: injection sample volume 81.7 µL, flow 8.0 mL/min, spectra acquisition time 1.4 s and linear range 1 to 40 mg L-1.

Cada dia, a análise química é mais cerca da automatização com o fim de satisfazer as necessidades atuais de resultados rápidos e confiáveis. Os sistemas de análise em fluxo (FIA - Flow Inyection Analysis) são uma das formas de aproximação à automatização. Este artigo apresenta os passos necessários para implementar uma metodologia FIA para a determinação de Pb(II) em água, partindo da revisão dos procedimentos clássicos e descrevendo detalhadamente os passos necessários para implementar a técnica de análise em fluxo. Os resultado são um método de análise de Pb em água que usa ditizona dissolvida em isopropanol (agente cromogénico) na presença de bromuro de cetiltrimetil amônio (CTAB), usado para solubilizar o complexo em água. As características principais do método foram: volume de injeção de amostra de 81,7 µL, velocidade de fluxo de 8,0 mL min-1, tempo de aquisição de espectros de 1,4 s e intervalo linear de 0.9 a 40 mg L-1.

Chemically facilitated chromium(VI) transport throughout an anion-exchange membrane application to an optical sensor for chromium(VI) monitoring.

The Raipore R1030 membrane, an anion-exchange membrane containing ammonium groups as ionogenic groups, was evaluated as the interface of an optical sensor for Cr(VI), and the effect of chemical parameters affecting Cr(VI) transport were studied. Good transport features were obtained, demonstrating the suitability of the Raipore R1030 membrane for this application. Thus, an optical sensor for chromium(VI) monitoring in industrial process waters was developed. The sensor is based on the renewable reagent approach and uses the Raipore R1030 membrane as the interface between the sample and the sensor head, which contains 1,5-diphenylcarbazide as spectrophotometric reagent for chromium. Chromium(VI) crosses the membrane and reacts with the reagent inside the sensor head, resulting in changes in the absorption of light. These changes are monitored in situ through a system of optical fibers. The sensor performance was tested by analysing samples from a waste water treatment plant for effluents from electroplating industries.