301 research outputs found
Desenvolvimento sustentåvel, conseqßentes inovaçþes tecnológicas e o futuro da mineração na Amazônia
This text analyses some environment problems caused by extraction and ore processing interested for the Amazonia including the Brazilian one and its social consequences as well as the project and the producing of products besides environmental and friendly socially processes been known as sustained.Este texto analisa alguns problemas ambientais causados pela extração e pelo processamento de bens minerais, de interesse para a Amazônia, inclusive a brasileira, e suas conseqßências sociais, tendo em vista o projeto e a produção de produtos e processos ambientalmente e socialmente amigåveis, conhecidos como sustentåveis
Genome-scale metabolic network of the central carbon metabolism of Enterococcus faecalis
The profound advance in experimental high throughput techniques (generally referred to as omics techniques) has enabled the analysis of a large number of components within a living cell. The vast amount of data obtained from the different omics (genomics, proteomics, fluxomics, metabolomics, transcriptomics) demands the use of bioinformatics tools. These methods comprise the development of comparative tools and maintenance of databases for the analysis of genomics data, in addition to the construction of models for the analysis and integration of data in a system-wide approach. Enterococcus faecalis is a gram-positive bacterium that is getting more attention due to its two-face behavior. This natural inhabitant of the mammalian gastrointestinal tract is also an opportunist pathogen responsible for urinary tract infections, nosocomial infections, bacteremia and infective endocarditis. Besides, its intrinsic physiological properties such as inherent antibiotic resistance and exceptional ability to adapt to harsh conditions provide this organism with an enormous advantage in the infection processes. Here, we propose to reconstruct the genome scale metabolic network of the central carbon metabolism of Enterococcus faecalis using genome sequencing information available on different databases as well as proteomics and metabolomics data. The first metabolic model generated for this bacterium will allow correlating metabolite levels and fluxes which enables identification of key control points in its metabolism. As it has been previously shown for other organisms, the metabolic network reconstruction may serve as a valuable tool to predict the phenotypic behaviour under various genetic and environmental conditions.Supported by a PhD grant from the FCT (Portuguese Science Foundation): SFRH/BD/47016/2008 and funding from HRC (Health Research Council of New Zealand)
Os geminivĂrus em sistema de produção integrada de tomate indĂşstria.
bitstream/item/75714/1/ct-71.pd
Genome scale metabolic network reconstruction of pathogen â Enterococcus faecalis
Enterococcus faecalis is a Gram-positive bacterium that
is getting more attention due to its âtwo-faceâ behavior.
This natural inhabitant of the gastrointestinal
mammalian tract is also an opportunist pathogen
responsible for urinary tract infections, nosocomial
infections, bacteremia and infective endocarditis (1).
Since the metabolic reconstruction of Haemophilus
influenzae was published in 1999 (2), many other
researchers have focused their attention into the
possibilities that the new era of genome-scale metabolic
models could bring to the scientific scene, both in
prokaryotic and eukaryotic organisms
Metabolic network reconstruction of the central carbon metabolism of Enterococcus faecalis
The profound advance in experimental high throughput techniques (generally referred to as
âomics techniquesâ) has enabled the analysis of a large number of components within a living
cell. The vast amount of data obtained from the different âomicsâ (genomics, proteomics,
fluxomics, metabolomics, transcriptomics) demands the use of bioinformatics tools. These
methods comprise the development of comparative tools and maintenance of databases for the
analysis of genomics data, in addition to the construction of models for the analysis and
integration of data in a system-wide approach. Enterococcus faecalis is a Gram-positive
bacterium that is getting more attention due to its âtwo-faceâ behavior. This natural inhabitant of
the mammalian gastrointestinal tract is also an opportunist pathogen responsible for urinary tract
infections, nosocomial infections, bacteremia and infective endocarditis. Besides, its intrinsic
physiological properties such as inherent antibiotic resistance and exceptional ability to adapt to
harsh conditions provide this organism with an enormous advantage in the infection processes.
Here, we propose to reconstruct the genome scale metabolic network of the central carbon
metabolism of Enterococcus faecalis using genome sequencing information available on
different databases as well as proteomics and metabolomics data. The first metabolic model
generated for this bacterium will allow correlating metabolite levels and fluxes which enables
identification of key control points in its metabolism. As it has been previously shown for other
organisms, the metabolic network reconstruction may serve as a valuable tool to predict the
phenotypic behaviour under various genetic and environmental conditions
Metabolic footprint analysis of recombinant Escherichia coli strains during fed-batch fermentations
Metabolic footprinting has become a valuable analytical approach for the characterization of
phenotypes and the distinction of specific metabolic states resulting from environmental and/or
genetic alterations. The metabolic impact of heterologous protein production in Escherichia coli cells is of particular interest, since there are numerous cellular stresses triggered during this
process that limit the overall productivity. Because the knowledge on the metabolic responses in recombinant bioprocesses is still scarce, metabolic footprinting can provide relevant information
on the intrinsic metabolic adjustments. Thus, the metabolic footprints generated by Escherichia
coli W3110 and the ÎrelA mutant strain during recombinant fed-batch fermentations at different experimental conditions, were measured and interpreted. The IPTG-induction of the heterologous
protein expression resulted in the rapid accumulation of inhibitors of the glyoxylate shunt in the culture broth, suggesting the clearance of this anaplerotic route to replenish the TCA
intermediaries withdrawn for the additional formation of heterologous protein. Nutritional shifts
were also critical in the recombinant cellular metabolism, indicating that cells employ diverse strategies to counteract imbalances in the cellular metabolism, including the secretion of certain
metabolites that are, most likely, used as a metabolic relief to survival processes.The authors thank to Raphael Aggio for assisting in the automatic refinement and correction of the GC-MS data. This work was supported in part by the research project Bridging Systems and Synthetic Biology for the development of Improved Microbial Cell Factories (MIT-Pt/BS-BB/0082/2008) and HeliSysBio-Molecular Systems Biology Helicobacter pylori (FCT PTDC/EBB-EBI/104235/2008), both financed by the Portuguese Fundacao para a Ciencia e Tecnologia. Sonia Carneiro was also supported by a PhD grant from the same institution (ref. SFRH/BD/22863/2005)
Applying a metabolic footprinting approach to characterize the impact of the recombinant protein production in Escherichia coli
In this study metabolic footprinting was applied to evaluate the metabolic consequences of protein overproduction at slow growth conditions (Îź = 0.1 h-1). The extracellular metabolites detected by gas chromatography-mass spectrometry characterized the metabolic footprints before and after the induction of the recombinant protein production (i.e. pre- and post-induction phases). Metabolic footprinting enabled the discrimination between the two growth phases and ex-posed significant metabolic alterations in the extracellular milieu during the re-combinant processes.This work is partly funded by the Portuguese FCT (Fundacao para a Ciencia e Tecnologia) funded MIT-Portugal Program in Bioengineering (MIT-Pt/BSBB/0082/2008). The work of Sonia Carneiro is supported by a PhD grant from FCT (ref. SFRH/BD/22863/2005)
Influence of the RelA activity on E. coli metabolism by metabolite profiling of glucose-limited chemostat cultures
Metabolite profiling of E. coli W3110 and the isogenic ârelA mutant cells was used to characterize the RelA-dependent stringent control of metabolism under different growth conditions. Metabolic profiles were obtained by gas chromatographyâmass spectrometry (GC-MS) analysis and revealed significant differences between E. coli strains grown at different conditions. Major differences between the two strains were assessed in the levels of amino acids and fatty acids and their precursor metabolites, especially when growing at the lower dilution rates, demonstrating differences in their metabolic behavior. Despite the fatty acid biosynthesis being the most affected due to the lack of the RelA activity, other metabolic pathways involving succinate, lactate and threonine were also affected. Overall, metabolite profiles indicate that under nutrient-limiting conditions the RelA-dependent stringent response may be elicited and promotes key changes in the E. coli metabolism.The authors thank to Raphael Aggio for assisting in the automatic refinement and correction of the GC-MS data, Katie Smart for performing acetate analyses and Clark Ehlers for his support with the bioreactor set up. This work was supported by the Portuguese FCT (Fundacao para a Ciencia e Tecnologia) funded MIT-Portugal Program in Bioengineering (MIT-Pt/BS-BB/0082/2008) and by ERDF-European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT (Portuguese Foundation for Science and Technology) within the project FCOMP-01-0124-FEDER-009707 (HeliSysBio. molecular Systems Biology in Helicobacter pylori). The work was also supported by a PhD grant from FCT (ref. SFRH/BD/22863/2005)
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