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Aimed at the growing interest in printed batteries, widely used industrial gravure printing was recently proven to be able to produce high-quality electrodes for lithium-ion batteries (LiBs), demonstrating its utility in the study of new functional materials. Here, for the first time, gravure printing was investigated for the mass production of well-known low-cost graphite-based anodes for LiBs. Graphite was also chosen as a case study to explore the influence of process parameters on the layer microstructure and the performance of the printed anodes. In particular, upon decreasing the size of the active material nanoparticles through ball-milling, an enhancement in anode performance was observed, which is related to an improvement in the material distribution in the printed layer, even in the case of increasing mass loading through a multilayer approach. A further improvement in performance, close to the theoretical capacity, was possible by changing the ink parameters, obtaining a denser microstructure of the printed anode. Such good results further demonstrate the possibility of using gravure printing for the mass production of electrodes for printed batteries and, in general, components in the field of energy.
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Nanostructured titania is one of the most commonly encountered constituents of nanotechnology devices for use in energy-related applications, due to its intrinsic functional properties as a semiconductor and to other favorable characteristics such as ease of production, low toxicity and chemical stability, among others. Notwithstanding this diffusion, the quest for improved understanding of the physical and chemical mechanisms governing the material properties and thus its performance in devices is still active, as testified by the large number of dedicated papers that continue to be published. In this framework, we consider and analyze here the effects of the material morphology and structure in determining the energy transport phenomena as cross-cutting properties in some of the most important nanophase titania applications in the energy field, namely photovoltaic conversion, hydrogen generation by photoelectrochemical water splitting and thermal management by nanofluids. For these applications, charge transport, light transport (or propagation) and thermal transport are limiting factors for the attainable performances, whose dependence on the material structural properties is reviewed here on its own. This work aims to fill the gap existing among the many studies dealing with the separate applications in the hope of stimulating novel cross-fertilization approaches in this research field.
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BACKGROUND: An Enhanced Recovery After Surgery (ERAS) program in colorectal surgery is able to significantly reduce the morbidity rates and postoperative hospital stay (LOS) related to the intervention. However, it is not clear what modalities and levels of implementation are necessary to achieve these results. The purpose of this work is to analyze the methods and results of the first year of implementation of the program in two centers of the Agenzia Sanitaria Unica Regionale (ASUR) Marche. MATERIALS: After a structured implementation pathway, characterized by the creation of a core team, field training, internal courses and coaching, the details of 196 consecutive cases of patients submitted to colorectal resection over a one-year period in two surgical units of the ASUR Marche were prospectively loaded in a database, considering over 50 variables including adherence to the individual items of the ERAS program. The primary outcomes were: overall and major morbidity, mortality and anastomotic dehiscence rates; secondary outcomes were: LOS, re-admission and re-intervention rates. The results of primary endpoints were evaluated by univariable and multivariable analyses with logistic regression and, thereafter, according to ERAS item adherence rate. RESULTS: After a median (interquartile range, IQR) follow-up of 40 (32-94) days, we recorded complications in 72 patients (overall morbidity 36.7%), major morbidity in 14 patients (7.1%), 6 deaths (mortality 3.1%), an anastomotic dehiscence in 9 cases (4.9%), median (IQR) overalll LOS 5 (3-7) days, 10 readmissions (5.1%) and 13 reoperations (6.7%). The mean adherence rate to the items of the ERAS program was 85.4%, showing a significant dose-effect curve for overall morbidity, major morbidity, anastomotic leakage and for overall LOS. DISCUSSION: The ERAS implementation methods in this project led to a high adherence (>80%) to the program items. All the results showed a significant improvement compared to the previous pre-implementation period and according to the adherence to program items rate.
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Cirurgia Colorretal , Recuperação Pós-Cirúrgica Melhorada , Humanos , Tempo de Internação , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controleRESUMO
Since 2011, the European Food Safety Authority (EFSA) has implemented combined difference and equivalence testing of agronomic, phenotypic, and composition data in the risk assessment of genetically modified crops. A short perspective is provided on misunderstandings that have shown up in published criticisms of the approach to equivalence testing, different viewpoints regarding the questions to be answered, and new developments in statistical modeling.
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Produtos Agrícolas/química , Análise de Alimentos/métodos , Plantas Geneticamente Modificadas/química , Qualidade de Produtos para o Consumidor , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Inocuidade dos Alimentos , Alimentos Geneticamente Modificados , Humanos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Medição de RiscoRESUMO
EFSA carries out the risk assessment of genetically modified organisms (GMOs) submitted under Regulation (EC) 1829/2003 and Regulation (EU) 503/2013. Dietary exposure is an essential element of the risk assessment on genetically modified (GM) foods. Dietary exposure estimations should cover average and high consumers across all the different age classes and special population groups and identify and consider particular consumer groups with expected higher exposure. This EFSA statement provides guidance on how human dietary exposure to newly expressed proteins in GM foods should be estimated using a deterministic model that makes use of the available information. Summary statistics of consumption of foods containing, consisting of and produced from crops relevant for the assessment of GMO applications are available in the EFSA website together with different factors to convert the reported consumption of processed foods into raw primary commodities. Guidance is also provided on how concentration data of newly expressed proteins, typically determined in raw primary commodities, should be used (materials to be analysed, growth stage, descriptive statistics to be used, etc.). An overview of the different uncertainties linked to the dietary exposure estimations is provided, informing on the strengths and limitations of the assessment. The document also describes the information applicants need to provide on human dietary exposure to allow EFSA doing an appropriate evaluation of the assessment provided as part of the application dossiers.
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Common pillar across the risk assessment strategies implemented worldwide for genetically modified plants is the comparison of their compositional profile to that of conventional counterparts deemed safe. If differences are observed, those that cannot be attributed to natural variation are further evaluated for their safety relevance. This principle is clear, but its implementation is challenging. Here we first discuss the difficulties of estimating natural variation of crop-specific compositional end-points and the various attempts made, together with their advantages and limitations. Second we present the empirical distribution curves of compositional end-points for two crops bearing a large commercial interest worldwide, maize and soybean. These curves provide novel information on end-point specific variability relevant for further progressing in the risk assessment process.
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Produtos Agrícolas/química , Alimentos Geneticamente Modificados/normas , Glycine max/química , Plantas Geneticamente Modificadas/química , Zea mays/química , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Europa (Continente) , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Glycine max/genética , Glycine max/metabolismo , Zea mays/genética , Zea mays/metabolismoRESUMO
Identifying and assessing unintended effects in genetically modified food and feed are considered paramount by the Food and Agricultural Organization (FAO), World Health Organization (WHO), and Codex Alimentarius, despite heated debate. This paper addresses outstanding needs: building consensus on the history-of-safe-use concept, harmonizing criteria to select appropriate conventional counterparts, and improving endpoint selection to identify unintended effects.
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Agricultura/ética , Consenso , Inocuidade dos Alimentos/métodos , Plantas Geneticamente Modificadas/química , Agricultura/métodos , Ração Animal/análise , Bases de Dados Factuais , Alimentos Geneticamente Modificados/provisão & distribuição , Regulamentação Governamental , Humanos , Medição de Risco , Terminologia como AssuntoRESUMO
This document provides guidance for the risk assessment under Regulation (EC) No 1829/2003 of the unintended, adventitious or technically unavoidable presence in food and feed of low level of genetically modified plant material intended for markets other than in the European Union. In this context, the presence at low level is defined to be maximum 0.9% of genetically modified plant material per ingredient. This guidance is intended to assist applicants by indicating which scientific requirements of Annex II of Regulation (EU) No 503/2013 are considered necessary for the risk assessment of the presence at low levels of genetically modified plant material in food and feed.
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The general principles for safety and nutritional evaluation of foods and feed and the potential health risks associated with hazardous compounds are described as developed by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) and further elaborated in the European Union-funded project Safe Foods. We underline the crucial role of sampling in foods/feed safety assessment. High quality sampling should always be applied to ensure the use of adequate and representative samples as test materials for hazard identification, toxicological and nutritional characterization of identified hazards, as well as for estimating quantitative and reliable exposure levels of foods/feed or related compounds of concern for humans and animals. The importance of representative sampling is emphasized through examples of risk analyses in different areas of foods/feed production. The Theory of Sampling (TOS) is recognized as the only framework within which to ensure accuracy and precision of all sampling steps involved in the field-to-fork continuum, which is crucial to monitor foods and feed safety. Therefore, TOS must be integrated in the well-established FAO/WHO risk assessment approach in order to guarantee a transparent and correct frame for the risk assessment and decision making process.
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Ração Animal/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Inocuidade dos Alimentos/métodos , Projetos de Pesquisa/normas , Animais , Manipulação de Alimentos/normas , Humanos , Medição de Risco , Testes de ToxicidadeAssuntos
Ração Animal/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Inocuidade dos Alimentos/métodos , Animais , Contaminação de Alimentos/legislação & jurisprudência , Humanos , Legislação sobre Alimentos , Projetos de Pesquisa , Medição de RiscoRESUMO
Material heterogeneity influences the effectiveness of sampling procedures. Most sampling guidelines used for assessment of food and/or feed commodities are based on classical statistical distribution requirements, the normal, binomial, and Poisson distributions-and almost universally rely on the assumption of randomness. However, this is unrealistic. The scientific food and feed community recognizes a strong preponderance of non random distribution within commodity lots, which should be a more realistic prerequisite for definition of effective sampling protocols. Nevertheless, these heterogeneity issues are overlooked as the prime focus is often placed only on financial, time, equipment, and personnel constraints instead of mandating acquisition of documented representative samples under realistic heterogeneity conditions. This study shows how the principles promulgated in the Theory of Sampling (TOS) and practically tested over 60 years provide an effective framework for dealing with the complete set of adverse aspects of both compositional and distributional heterogeneity (material sampling errors), as well as with the errors incurred by the sampling process itself. The results of an empirical European Union study on genetically modified soybean heterogeneity, Kernel Lot Distribution Assessment are summarized, as they have a strong bearing on the issue of proper sampling protocol development. TOS principles apply universally in the food and feed realm and must therefore be considered the only basis for development of valid sampling protocols free from distributional constraints.
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Ração Animal/análise , Análise de Alimentos/métodos , Projetos de Pesquisa/normas , Contaminação de Alimentos , Viés de Seleção , Glycine max/químicaRESUMO
The general principles for safety and nutritional evaluation of foods and feed and the potential health risks associated with hazardous compounds are described as developed by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) and further elaborated in the European Union-funded project Safe Foods. We underline the crucial role of sampling in foods/feed safety assessment. High quality sampling should always be applied to ensure the use of adequate and representative samples as test materials for hazard identification, toxicological and nutritional characterization of identified hazards, as well as for estimating quantitative and reliable exposure levels of foods/feed or related compounds of concern for humans and animals. The importance of representative sampling is emphasized through examples of risk analyses in different areas of foods/feed production. The Theory of Sampling (TOS) is recognized as the only framework within which to ensure accuracy and precision of all sampling steps involved in the field-to-fork continuum, which is crucial to monitor foods and feed safety. Therefore, TOS must be integrated in the well-established FAO/WHO risk assessment approach in order to guarantee a transparent and correct frame for the risk assessment and decision making process.
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Genetically modified organisms (GMOs) and derived food and feed products are subject to a risk analysis and regulatory approval before they can enter the market in the European Union (EU). In this risk analysis process, the role of the European Food Safety Authority (EFSA), which was created in 2002 in response to multiple food crises, is to independently assess and provide scientific advice to risk managers on any possible risks that the use of GMOs may pose to human and animal health and the environment. EFSA's scientific advice is elaborated by its GMO Panel with the scientific support of several working groups and EFSA's GMO Unit. This review presents EFSA's scientific activities and highlights its achievements on the risk assessment of GMOs for the first 10 years of its existence. Since 2002, EFSA has issued 69 scientific opinions on genetically modified (GM) plant market registration applications, of which 62 for import and processing for food and feed uses, six for cultivation and one for the use of pollen (as or in food), and 19 scientific opinions on applications for marketing products made with GM microorganisms. Several guidelines for the risk assessment of GM plants, GM microorganisms and GM animals, as well as on specific issues such as post-market environmental monitoring (PMEM) were elaborated. EFSA also provided scientific advice upon request of the European Commission on safeguard clause and emergency measures invoked by EU Member States, annual PMEM reports, the potential risks of new biotechnology-based plant breeding techniques, evaluations of previously assessed GMOs in the light of new scientific publications, and the use of antibiotic resistance marker genes in GM plants. Future challenges relevant to the risk assessment of GMOs are discussed. EFSA's risk assessments of GMO applications ensure that data are analysed and presented in a way that facilitates scientifically sound decisions that protect human and animal health and the environment.
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Animais Geneticamente Modificados , Biotecnologia , Alimentos Geneticamente Modificados , Plantas Geneticamente Modificadas , Animais , União Europeia , Humanos , Medição de RiscoRESUMO
BACKGROUND: Safety assessment of genetically modified organisms is currently often performed by comparative evaluation. However, natural variation of plant characteristics between commercial varieties is usually not considered explicitly in the statistical computations underlying the assessment. RESULTS: Statistical methods are described for the assessment of the difference between a genetically modified (GM) plant variety and a conventional non-GM counterpart, and for the assessment of the equivalence between the GM variety and a group of reference plant varieties which have a history of safe use. It is proposed to present the results of both difference and equivalence testing for all relevant plant characteristics simultaneously in one or a few graphs, as an aid for further interpretation in safety assessment. A procedure is suggested to derive equivalence limits from the observed results for the reference plant varieties using a specific implementation of the linear mixed model. Three different equivalence tests are defined to classify any result in one of four equivalence classes. The performance of the proposed methods is investigated by a simulation study, and the methods are illustrated on compositional data from a field study on maize grain. CONCLUSIONS: A clear distinction of practical relevance is shown between difference and equivalence testing. The proposed tests are shown to have appropriate performance characteristics by simulation, and the proposed simultaneous graphical representation of results was found to be helpful for the interpretation of results from a practical field trial data set.
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Plantas Geneticamente Modificadas/química , Zea mays/química , Interpretação Estatística de Dados , Computação Matemática , Plantas Geneticamente Modificadas/genética , Zea mays/genéticaRESUMO
A Windows-based software tool [Analytical Method Performance Evaluation (AMPE)] was developed to support the validation of analytical methods. The software implements standard statistical approaches commonly adopted in validation studies to estimate analytical method performance (limits of detection and quantitation, accuracy, specificity, working range, and linearity of responses) according to ISO 5725. In addition, AMPE proposes the application of innovative and unique approaches for the assessment of analytical method performance. Specifically, AMPE proposes the use of difference-based indexes to quantify the agreement between measurements and reference values, the use of pattern indexes to quantify methods bias with respect to specific external variables, and the application of fuzzy logic to aggregate into synthetic indicators the information collected independently via the different performance statistics traditionally estimated in validation studies. Aggregated measures are particularly useful for methods comparison, when more than one method is available for a specific analysis and it may be of interest to identify the best performing one taking into account, simultaneously, the information available from different performance statistics. Illustrative examples of the type of outputs expected from AMPE-based validation sessions are given. The extensive data handling capabilities and the wide range of statistics supplied in the software package makes AMPE suitable for specific needs that may arise in different validation studies. The installation package, complete with a fully documented help file, is distributed free of charge to interested users along with input files exemplary of the type of entry data required to run validation data analyses.
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Técnicas de Química Analítica/métodos , Calibragem , Técnicas de Química Analítica/normas , Técnicas de Laboratório Clínico , Estudos de Avaliação como Assunto , Internet , Modelos Estatísticos , Valores de Referência , Análise de Regressão , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , SoftwareRESUMO
OBJECTIVES: The study was undertaken to investigate vancomycin-resistant (vanA) Enterococcus faecalis isolates carrying aggregation substance (AS) gene(s) for their ability to co-transfer vanA and AS genes. METHODS: Six vanA clumping-positive E. faecalis isolates (five human and one food sample) carrying one or more AS genes (prgB, asa1, asa373) were analysed for co-transfer of vanA and AS genes to E. faecalis JH2-2 and Enterococcus faecium 64/3. RESULTS: E. faecalis isolates harboured one or multiple plasmids carrying vanA, one or more AS gene(s) or both. vanA was transferred to JH2-2 (frequencies of 10(-3)-10(-6)) from all donors and to 64/3 (10(- 6)-10(- 8)) only from donors from humans. AS genes were detected in 51/60 (85%) of JH2-2 and in 20/50 (40%) of 64/3 vanA transconjugants (prgB, asa1, asa373 or prgB asa373), of which a total of 53.6% were clumping-positive. The plasmid content of JH2-2 transconjugants from the same donor was either identical to that of the donor or it was completely different, suggesting different mechanisms for co-transfer (location on the same pheromone plasmid, mobilization of vanA plasmids by the pheromone-inducible conjugation system, rearrangement of plasmid content during matings). After induction with pheromones, a marked increase in adhesion to Caco-2 cells was observed in four isolates and in some JH2-2 transconjugants, all clumping-positive. CONCLUSIONS: Findings suggest that co-transfer of vanA and AS genes may be a common feature of E. faecalis isolates. Since AS is recognized as a virulence factor, this feature might contribute to the emergence of strains with enhanced ability to cause infection and disease in humans.
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Proteínas de Bactérias/genética , Carbono-Oxigênio Ligases/genética , Enterococcus faecalis/genética , Resistência a Vancomicina/genética , Aderência Bacteriana , Células CACO-2 , Conjugação Genética , Enterococcus faecalis/isolamento & purificação , Enterococcus faecalis/fisiologia , Enterococcus faecium/genética , Microbiologia de Alimentos , Humanos , Feromônios/genética , Vancomicina , Fatores de VirulênciaRESUMO
Bile-resistant bacteria, particularly gram-positive Enterococcus faecalis and Enterococcus faecium, play an important role in biliary stent occlusion, because their sessile mode of growth protects them against host defenses and antimicrobial agents. Twelve E. faecalis and seven E. faecium strains isolated from occluded biliary stents have been investigated for slime production, presence of aggregation substance genes, and ability to adhere to Caco-2 cells. Ten isolates were strong producers of slime, and seven isolates produced clumps when exposed to pheromones of E. faecalis JH2-2 and/or OG1RF. The small E. faecium clumps differed from the large clumps of E. faecalis and were similar to those of E. faecium LS10(pBRG1) carrying a pheromone response plasmid. After induction with pheromones, the adhesion to Caco-2 cells of clumping-positive strains was found to increase from two- to fourfold. Amplicons of the expected size were detected in three clumping-positive and three clumping-negative E. faecalis isolates by using primers (agg) internal to a highly conserved region of the E. faecalis pheromone response plasmids pAD1, pPD1, and pCF10 and primers internal to prgB of the E. faecalis plasmid pCF10. The agg/prgB-positive E. faecalis strains were also positive in Southern hybridization experiments with a prgB-specific probe. No PCR products were obtained with the same primers from four clumping-positive isolates (one E. faecalis and three E. faecium strains), which were also Southern hybridization negative. Our results demonstrate that slime production and pheromone response are both present in isolated enterococci, suggesting that clinical strains with these features might have a selective advantage in colonizing biliary stents.
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Doenças dos Ductos Biliares/terapia , Ductos Biliares/microbiologia , Enterococcus/isolamento & purificação , Feromônios/fisiologia , Stents/microbiologia , Aderência Bacteriana/fisiologia , Bile/microbiologia , Linhagem Celular Tumoral , Neoplasias do Colo , Eletroforese em Gel de Campo Pulsado , Enterococcus/genética , Enterococcus/crescimento & desenvolvimento , Enterococcus/fisiologia , Enterococcus faecalis/genética , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/isolamento & purificação , Enterococcus faecalis/fisiologia , Humanos , Plasmídeos/genética , RecidivaRESUMO
The RD2 region of the internalization-associated gene prtF1, which encodes the fibronectin-binding repeat domain type 2 of protein F1, plays a crucial role in the entry of group A streptococci (GAS) into epithelial cells. A molecular study of the variability of the RD2 region was carried out with 77 independent Italian GAS, 66 erythromycin resistant (ER) and 11 erythromycin susceptible (ES), which had previously been investigated for the association between erythromycin resistance and ability to enter human respiratory cells. The amplicons obtained from PCR analysis of the RD2 region were consistent with a number of RD2 repeats ranging from one to five, more frequently four (n = 30), three (n = 27), and one (n = 18). A new method to type cell-invasive GAS (RD2 typing) was developed by combining PCR analysis of the RD2 region and restriction analysis of PCR products with endonucleases HaeIII, DdeI, and HinfI. Overall, 10 RD2 types (a to j) were distinguished (all detected among the 66 ER isolates, four detected among the 11 ES isolates). Comparison and correlation of RD2 typing data with the genotype and phenotype of macrolide resistance and with data from PCR M typing and SmaI macrorestriction analysis allowed us to identify 41 different clones (31 among the 66 ER isolates and 10 among the 11 ES isolates). Three major clones accounted for 40% of the isolates (47% of ER strains). Some ES isolates appeared to be related to ER isolates with identical combinations of RD2 type and emm type. While simultaneous use of different typing methods is essential for a thorough investigation of GAS epidemiology, RD2 typing may be especially helpful in typing cell-invasive GAS.
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Adesinas Bacterianas/genética , Eritromicina/farmacologia , Variação Genética , Streptococcus pyogenes/genética , Criança , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Farmacorresistência Bacteriana/genética , Eletroforese em Gel de Campo Pulsado , Humanos , Testes de Sensibilidade Microbiana , Faringite/microbiologia , Reação em Cadeia da Polimerase , Infecções Estreptocócicas/diagnóstico , Streptococcus pyogenes/efeitos dos fármacos , Streptococcus pyogenes/isolamento & purificaçãoRESUMO
In Europe, a growing interest for reliable techniques for the quantification of genetically modified component(s) of food matrixes is arising from the need to comply with the European legislative framework on novel food products. Real-time polymerase chain reaction (PCR) is currently the most powerful technique for the quantification of specific nucleic acid sequences. Several real-time PCR methodologies based on different molecular principles have been developed for this purpose. The most frequently used approach in the field of genetically modified organism (GMO) quantification in food or feed samples is based on the 5'-3'-exonuclease activity of Taq DNA polymerase on specific degradation probes (TaqMan principle). A novel approach was developed for the establishment of a TaqMan quantification system assessing GMO contents around the 1% threshold stipulated under European Union (EU) legislation for the labeling of food products. The Zea mays T25 elite event was chosen as a model for the development of the novel GMO quantification approach. The most innovative aspect of the system is represented by the use of sequences cloned in plasmids as reference standards. In the field of GMO quantification, plasmids are an easy to use, cheap, and reliable alternative to Certified Reference Materials (CRMs), which are only available for a few of the GMOs authorized in Europe, have a relatively high production cost, and require further processing to be suitable for analysis. Strengths and weaknesses of the use of novel plasmid-based standards are addressed in detail. In addition, the quantification system was designed to avoid the use of a reference gene (e.g., a single copy, species-specific gene) as normalizer, i.e., to perform a GMO quantification based on an absolute instead of a relative measurement. In fact, experimental evidences show that the use of reference genes adds variability to the measurement system because a second independent real-time PCR-based measurement must be performed. Moreover, for some reference genes no sufficient information on copy number in and among genomes of different lines is available, making adequate quantification difficult. Once developed, the method was subsequently validated according to IUPAC and ISO 5725 guidelines. Thirteen laboratories from 8 EU countries participated in the trial. Eleven laboratories provided results complying with the predefined study requirements. Repeatability (RSDr) values ranged from 8.7 to 15.9%, with a mean value of 12%. Reproducibility (RSDR) values ranged from 16.3 to 25.5%, with a mean value of 21%. Following Codex Alimentarius Committee guidelines, both the limits of detection and quantitation were determined to be <0.1%.
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Genes de Plantas/genética , Plantas Geneticamente Modificadas/genética , Zea mays/genética , Sequência de Bases , Soluções Tampão , Calibragem , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , União Europeia , Rotulagem de Alimentos , Genoma de Planta , Dados de Sequência Molecular , Plasmídeos/genética , Padrões de Referência , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Sex pheromone plasmids, frequently found in Enterococcus faecalis, have rarely been detected in Enterococcus faecium. pBRG1 is an approximately 50-kb vanA-carrying conjugative plasmid of an E. faecium clinical isolate (LS10) that is transferable to E. faecalis laboratory strains. In cell infection experiments, E. faecium LS10 exhibited remarkably high invasion efficiency and produced cytopathogenic effects in Caco-2 cell monolayers. Growth in the presence of sex pheromones produced by E. faecalis JH2-2 was found to cause self-aggregation of both E. faecium LS10 and E. faecalis JH-RFV(pBRG1) (a transconjugant obtained by transfer of pBRG1 to E. faecalis JH2-2) and to increase the cell adhesion and invasion efficiencies of both E. faecium LS10 and E. faecalis JH-RFV(pBRG1). Sex pheromone cCF10 caused clumping of E. faecalis OG1RF(pBRG1) (a transconjugant obtained by transfer of pBRG1 to E. faecalis OG1RF) at a concentration approximately 100-fold higher than the one required for the control strain E. faecalis OG1RF(pCF10). PCR products of the expected sizes were obtained with primers internal to aggregation substance genes of E. faecalis pheromone response plasmids pAD1, pPD1, and pCF10 and primers internal to ash701 of E. faecium pheromone plasmid pHKK701. These findings suggest that pBRG1 of E. faecium LS10 is a sex pheromone response plasmid.