RESUMEN

The assessment of food authenticity is a topic that gained a lot of interest at the international level. This term includes misidentification of variety, origin, production system, processing but also adulteration. These frauds all have an analytical component, and research tends to offer new analytical solutions to manage them. One of them is non-targeted approaches, which get around the limitations of targeted analysis by detecting the unexpected. A wide range of products are studied such as wine, rice, olive oil, spices, and honey among the top five. Geographic origin is by far the fraud with the most attention. The main reason is probably the complexity to consider terroir effect and every other variable to determine an area of production. This review offers an overview of the potential of non-targeted analysis to assess food authenticity. These results also illustrate the capability to look for environmental terroir markers that could be cross-matrixes.

Asunto(s)

Miel , Vino , Biomarcadores/análisis , Contaminación de Alimentos/análisis , Miel/análisis , Metabolómica , Vino/análisis

RESUMEN

There are several analytical procedures available for the monitoring of volatile organic compounds (VOCs) in the air, which differ mainly on sampling procedures. The Coriolis micro air sampler is a tool normally designed for biological air sampling. In this paper, the Coriolis micro bio collector is used to evaluate its ability to sample organic contaminants sampling and detecting them when combined GC-MS. We also compare the use of the Coriolis micro with a standardized sampling method, which is the use of a lung box with a Nalophan® bag. The results show that the Coriolis micro sampling method is suitable for the sampling of organic contaminants. Indeed, the Coriolis micro allows to sample and detect mainly semi-volatile molecules, while the lung box/Nalophan® bags allow to sample more volatile molecules (highly volatile and volatile). These results were confirmed in the controlled air lab with a slight difference with the field. The simultaneous use of the both techniques allow to sample and detect a larger number of molecules with specific physicochemical properties to each sampling technique. In conclusion, the Coriolis micro can sample and detect volatile organic compounds present in air. We have shown that the development of alternative sampling methods and the use of non-target analysis are essential for a more comprehensive risk assessment. Moreover, the use of the Coriolis micro allows the detection of emergent molecules around the Thau lagoon.

Asunto(s)

Compuestos Orgánicos Volátiles , Monitoreo del Ambiente/métodos , Cromatografía de Gases y Espectrometría de Masas , Tereftalatos Polietilenos , Compuestos Orgánicos Volátiles/análisis

RESUMEN

Environment can be affected by a variety of micropollutants. In this paper, we develop a system to assess the toxicity on an environmental sample, based on the expression of a nanoluciferase under the control of the STB5 promotor in a yeast. The STB5 gene encodes for a transcription factor involved in a pleiotropic drug resistance and in the oxidative stress response. The response of the modified yeast was assessed using 42 micropollutants belonging to different families (antibiotics, pain killers, hormones, plasticizers, pesticides, etc.). Among them, 26 induced an increase of the bioluminescence for concentration ranges from pg.L-1 to ng.L-1. Surprisingly, for concentrations higher than 100 ng.L-1, no response can be observed, suggesting that other mechanisms are involved when the stress increases. Analyzing the different responses obtained, we highlighted six nonmonotonic types of responses. The type of response seems to be independent of the properties of the compounds (polarity, toxicology, molecular weight) and of their family. In conclusion, we highlighted that a cellular response exists for very low exposition to environmental concentration of micropollutants and that it was necessary to explore the cellular mechanisms involved at very low concentration to provide a better risk assessment.

Asunto(s)

Plaguicidas , Proteínas de Saccharomyces cerevisiae , Humanos , Estrés Oxidativo , Saccharomyces cerevisiae/genética , Factores de Transcripción/metabolismo

RESUMEN

Molecular approaches are powerful tools that are used for medical or environmental diagnoses. However, the main limitations of such a tools are that they extract low levels of DNA and they do not remove the inhibitors of polymerase chain reaction (PCR). Although the use of polycation to complex and purify DNA has been described in the literature, elution often requires a high ionic strength or pH levels not compatible with molecular analyses. In this paper, we described a new process that is based on the complexation of DNA with linear polylysine, followed by capturing the complex by a cation exchange resin. The originality of the process consisted of using mechanic force to elute DNA from the complex. The extraction method showed several advantages when compared to existing methods, such as being compatible with pH levels that range from 5 to 11, as well as high levels of DNA recovery and elimination of PCR inhibitors from complex samples. This method was successfully applied to different types of samples, such as environmental samples, beverage samples, and medical samples. Furthermore, it was proven to be a good solution for removing PCR inhibitors and assuring good DNA recovery yield.

RESUMEN

For the analysis of volatile bacterial compounds, solid phase microextraction (SPME) is currently the most widely used metabolite concentration technique. Recently, the potential of stir bar sorptive extraction (SBSE) for this use has been demonstrated. These two approaches were therefore used in combination with gas-chromatography coupled with mass-spectrometry (GC-MS) for the analysis of volatile and semi-volatile bacterial compounds produced by Staphylococcus aureus. In both cases, SPME and SBSE/headspace sorptive extraction (HSSE) enrichment was carried out in two coating phases. A whole analytical and statistical process was developed to differentiate the metabolites produced from the metabolites consumed. The results obtained with SBSE/HSSE and SPME were compared and showed the recovery of 90% of the compounds by SBSE/HSSE. In addition, we were able to detect the production of 12 volatile/semi-volatile compounds by S. aureus, six of which had never been reported before. The extraction by SBSE/HSSE showed higher concentration capacities and greater sensitivity than SPME concerning bacterial compounds, suggesting that this technique may therefore become the new preferred option for bacterial volatile and semi-volatile compound analysis.

Asunto(s)

Hidrocarburos Aromáticos/química , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/metabolismo , Compuestos Orgánicos Volátiles/química , Aminas/química , Aminas/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas , Hidrocarburos Aromáticos/aislamiento & purificación , Metaboloma/genética , Microextracción en Fase Sólida , Infecciones Estafilocócicas/metabolismo , Staphylococcus aureus/química , Compuestos Orgánicos Volátiles/aislamiento & purificación

RESUMEN

We propose a new approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and headspace sorptive extraction (HSSE). Stir bars have so far never been used for the extraction of volatile/semi-volatile bacterial compounds. The effectiveness of two stir bars with polydimethylsiloxane (PDMS) or ethylene glycol/silicone (EGS) as sorbent was tested by performing sample extraction directly in gas chromatography (GC) vials containing bacterial cultures. Several combinations of desorption and extraction were tested at different growth times. When the extraction was carried out simultaneously with the EGS stir bar in headspace and the PDMS in the bacterial culture, the number of extracted compounds was significantly increased. Using both twisters increased the polarity range of the compounds found, and extraction at the end of the exponential phase of growth generated the best yields. This method was successfully applied to determine the production of 17 molecules by a strain of Staphylococcus aureus. In conclusion, this study paves the way for a new method for determining the volatile metabolite profile of bacteria, which can provide a promising innovative alternative in the identification of biomarkers.

Asunto(s)

Técnicas de Química Analítica/instrumentación , Staphylococcus aureus/metabolismo , Compuestos Orgánicos Volátiles/análisis , Adsorción , Técnicas de Química Analítica/métodos , Dimetilpolisiloxanos/química , Glicol de Etileno/química , Siliconas/química , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/metabolismo

RESUMEN

AIM: We evaluated the performance of Unyvero implant and tissue infections system (ITI) application (Curetis) to diagnose Diabetic Foot Osteomyelitis (DFOM). PATIENTS & METHODS: The study was conducted in the Diabetic Foot reference center of Nîmes University Hospital (France) from 1 December 2016 to 31 May 2017. We compared the Unyvero ITI PCR to conventional culture and alternative molecular approaches. RESULTS: A total of 79 patients with DFOM were included: 177 microorganisms were isolated by culture, 146 detected by PCR, resulting in a concordance level of 66.7% (65.0-68.4). Discrepant results were obtained for 45 samples, with 59 microorganisms being detected by PCR only (18 samples) or by culture only (27 samples). CONCLUSION: Unyvero ITI PCR represents an interesting additional diagnosis solution to manage DFOM.

Asunto(s)

Pie Diabético/diagnóstico , Manejo de la Enfermedad , Reacción en Cadena de la Polimerasa Multiplex/instrumentación , Reacción en Cadena de la Polimerasa Multiplex/métodos , Osteomielitis/diagnóstico , Prótesis e Implantes , Sepsis/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/patogenicidad , Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Pie Diabético/microbiología , Farmacorresistencia Microbiana , Femenino , Francia , Hongos/genética , Hongos/aislamiento & purificación , Hongos/patogenicidad , Humanos , Masculino , Persona de Mediana Edad , Osteomielitis/microbiología , Infecciones Relacionadas con Prótesis/diagnóstico , Infecciones Relacionadas con Prótesis/microbiología , Sepsis/microbiología

RESUMEN

To determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6')-Ib andaac(3')-I genes].

Asunto(s)

Acetiltransferasas/genética , Infecciones por Acinetobacter/veterinaria , Acinetobacter baumannii/genética , Proteínas de Peces/genética , Resistencia betalactámica/genética , beta-Lactamasas/genética , Acetiltransferasas/metabolismo , Infecciones por Acinetobacter/epidemiología , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Argelia/epidemiología , Animales , Antibacterianos/farmacología , Carbapenémicos/farmacología , Enfermedades de los Peces/epidemiología , Enfermedades de los Peces/microbiología , Proteínas de Peces/metabolismo , Tracto Gastrointestinal/microbiología , Expresión Génica , Genotipo , Branquias/microbiología , Mar Mediterráneo/epidemiología , Perciformes , Filogenia , beta-Lactamasas/metabolismo

RESUMEN

Over the past two decades, the level of ethanol in wine has increased in most wine-producing regions, raising a number of issues related to consumer health, prevention policies, the effectiveness of the fermentation and wine sensorial quality. This review focuses on metabolic challenges and recent achievements in the development of Saccharomyces cerevisiae wine strains with reduced ethanol yield. Metabolic engineering approaches that have been successfully used to optimize endogenous pathways have been gradually replaced in recent years by evolutionary engineering strategies, which can generate strains with improved phenotypes using new circuits and can be put to immediate commercial use. The power of adaptive evolutionary strategies is expected to increase with the rapid development of whole-genome sequencing, which, combined with gene expression and metabolic flux analysis, enables the identification of the genetic basis of improved phenotypes and the transfer of such phenotypes between strains.

Asunto(s)

Etanol/análisis , Ingeniería Metabólica/métodos , Saccharomyces cerevisiae/metabolismo , Vino/análisis , Etanol/metabolismo , Fermentación , Expresión Génica , Vía de Pentosa Fosfato/genética , Saccharomyces cerevisiae/genética

RESUMEN

Nonylphenol (NP) is an endocrine disruptor with harmful effects including feminization and carcinogenesis on various organisms. This substance is a degradation product of nonylphenol ethoxylates (NPEO) that is used in several industrial and agricultural processes. In this paper, we examined the assessment of NP exposure on chick embryo development, using a concentration consistent with the environmental concentrations of NP. With this aim, NP (between 0.1 and 50 µg/egg) was injected into the yolk of egg through a small needle hole in the shell. We report the effect of NP on chick reproductive system development although the effect we observed is lower than those observed by exposition to other endocrine disruptors. However, histological analysis highlighted a decrease of intraluminal seminiferous surface area in 64.12% of case (P=0.0086) and an heterogeneous organization of the renal tubules when 10 µg/egg were injected. Moreover, an impairment of liver development with an abnormal bile spillage was observed when higher concentration of NP was injected (50 µg/egg).

Asunto(s)

Aves/embriología , Disruptores Endocrinos/toxicidad , Fenoles/toxicidad , Sistema Urogenital/efectos de los fármacos , Vísceras/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Animales , Embrión de Pollo , Disruptores Endocrinos/análisis , Sistema Urogenital/embriología , Vísceras/embriología , Contaminantes Químicos del Agua/análisis

RESUMEN

In the competitive context of the wine market, there is a growing interest for novel wine yeast strains that have an overall good fermentation capacity and that contribute favorably to the organoleptic quality of wine. Using an adaptive evolution strategy based on growth on gluconate as sole carbon source, we recently obtained wine yeasts with improved characteristics in laboratory-scale fermentations. The characteristics included enhanced fermentation rate, decreased formation of acetate and greater production of fermentative aroma. We report an evaluation of the potential value of the evolved strain ECA5™ for winemaking, by comparing its fermentation performance and metabolite production to those of the parental strain in pilot-scale fermentation trials, with various grape cultivars and winemaking conditions. We show that the evolved strain has outstanding attributes relative to the parental wine yeast strain, and in particular the production of less volatile acidity and greater production of desirable volatile esters, important for the fruity/flowery character of wines. This study highlights the potential of evolutionary engineering for the generation of strains with a broad range of novel properties, appropriate for rapid application in the wine industry.

Asunto(s)

Evolución Biológica , Saccharomyces cerevisiae/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Vino/microbiología , Adulto , Femenino , Fermentación , Humanos , Masculino , Odorantes/análisis , Saccharomyces cerevisiae/genética , Gusto , Vino/análisis

RESUMEN

Amplification of the flux toward the pentose phosphate (PP) pathway might be of interest for various S. cerevisiae based industrial applications. We report an evolutionary engineering strategy based on a long-term batch culture on gluconate, a substrate that is poorly assimilated by S. cerevisiae cells and is metabolized by the PP pathway. After adaptation for various periods of time, we selected strains that had evolved a greater consumption capacity for gluconate. (13)C metabolic flux analysis on glucose revealed a redirection of carbon flux from glycolysis towards the PP pathway and a greater synthesis of lipids. The relative flux into the PP pathway was 17% for the evolved strain (ECA5) versus 11% for the parental strain (EC1118). During wine fermentation, the evolved strains displayed major metabolic changes, such as lower levels of acetate production, higher fermentation rates and enhanced production of aroma compounds. These represent a combination of novel traits, which are of great interest in the context of modern winemaking.

Asunto(s)

Evolución Molecular Dirigida , Glucosa , Glucólisis/genética , Vía de Pentosa Fosfato/genética , Saccharomyces cerevisiae , Vino , Gluconatos/metabolismo , Glucosa/genética , Glucosa/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo

RESUMEN

In Saccharomyces cerevisiae, the oxidative stress-activated zinc cluster protein Stb5p activates genes involved in NADPH production and most genes of the pentose phosphate (PP) pathway. To gain insight into the role of Stb5p, we studied the behaviour of stb5 deletion mutants during aerobic and anaerobic growth on glucose. stb5 mutants were auxotrophic for methionine and pyrimidine nucleotides. The methionine auxotrophy phenotype was air dependent, suggesting an impaired aerobic NADPH status. Consistent with this, the acetate level was reduced and the α-ketoglutarate level was increased in the stb5 mutant. stb5 cells also required pyrimidine nucleotides for aerobic and anaerobic growth, consistent with a reduction in 5-phosphoribosyl-1-pyrophosphate production caused by a reduced flux through the PP pathway. Strains overexpressing STB5 could not grow on glucose. This growth defect was restored by overproduction of an NADPH-butanediol dehydrogenase, which reoxidizes the excess NADPH in the oxidative PP pathway. These findings suggest a major role for the transcription factor Stb5p in maintaining a basal flux through the PP pathway to meet the NADPH requirements for aerobic growth, and to provide the nucleotide precursors. Our data also demonstrate the potential use of a system based on overproduction of this transcription factor to increase flux through the PP pathway.

Asunto(s)

Regulación Fúngica de la Expresión Génica , Vía de Pentosa Fosfato/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiología , Factores de Transcripción/metabolismo , Activación Transcripcional , Acetatos/metabolismo , Aerobiosis , Eliminación de Gen , Ácidos Cetoglutáricos/metabolismo , Metionina/metabolismo , NADP/metabolismo , Fosforribosil Pirofosfato/metabolismo , Pirimidinas/metabolismo , Saccharomyces cerevisiae/metabolismo , Factores de Transcripción/deficiencia

RESUMEN

Saccharomyces cerevisiae strains lacking phosphoglucose isomerase (pgi1) cannot use the pentose phosphate (PP) pathway to oxidize glucose, which has been explained by the lack of mechanism for reoxidation of the NADPH surplus. Consistent with this, the defective growth on glucose of a ENYpgi1 strain can be partially restored by expressing the Escherichia coli transhydrogenase udhA. In this work it was found that growth of V5 (wine yeast-derived) and FY1679 (isogenic to S288C) pgi1 mutants is not rescued by expression of udhA. Moreover, the flux through the PP pathway of 11 S. cerevisiae strains from various origins was estimated, by calculating the ratio between the enzymatic activity of the G6PDH and HXK, placed at the glycolysis-PP pathway branch point. The results show that ENY.WA-1A exhibited the highest ratio (1.5-3-fold) and the highest G6PDH activity. Overexpression of ZWF1 encoding the G6PDH in V5pgi1udhA did not rescue growth on glucose, suggesting that steps downstream the G6PDH might limit the PP pathway in this strain. As a whole, these data highlight a great intraspecies diversity in the PP pathway capacity among S. cerevisiae strains and suggest that a low capacity may be the prime limiting factor in glucose oxidation through this pathway.

Asunto(s)

Glucosa-6-Fosfato Isomerasa/genética , Glucosa/metabolismo , NADP Transhidrogenasas/genética , Vía de Pentosa Fosfato , Pentosas/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Escherichia coli/enzimología , Escherichia coli/genética , Prueba de Complementación Genética , Hexoquinasa/metabolismo , NADP/análisis , Oxidación-Reducción , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/crecimiento & desarrollo