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Metabolic Burden (metabolic + burden)
Selected AbstractsAcinetobacter bioreporter assessing heavy metals toxicityJOURNAL OF BASIC MICROBIOLOGY, Issue 5 2006Desouky Abd-El-Haleem Dr. This work was conducted to employ a whole cell-based biosensor to monitor toxicity of heavy metals in water and wastewater. An isolate of industrial wastewater bacterium, Acinetobacter sp. DF4, was genetically modified with lux reporter gene to create a novel bioluminescent bacterial strain, designated as DF4/PUTK2. This bioreporter can investigate the toxicity through light inhibition due to cell death or metabolic burden and the specific stress effects of the tested soluble materials simultaneously. The use of Acinetobacter DF4/PUTK2 as a bioluminescent reporter for heavy metal toxicity testing and for the application of wastewater treatment influent toxicity screening is presented in this study. Among eight heavy metals tested, the bioluminescence of DF4/PUTK2 was most sensitive to Zn, Cd, Fe, Co, Cr followed by Cu in order of decreasing sensitivity. The same pattern of sensitivity was observed when several contaminated water and wastewater effluents were assayed. This work suggested that luxCDABE -marked Acinetobacter bacterium DF4/PUTK2 can be used to bioassay the ecotoxicity of wastewater and effluent samples contaminated with heavy metals. Using this assay, it is possible to pre-select the more toxic samples for further chemical analysis and to discard wastewater samples with low or no inhibition because they are not toxic to the environment. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Non-invasive detection of the metabolic burden on recombinant microorganisms during fermentation processes,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2001Th Bachinger Abstract Heterologous protein production is an important source of therapeutic products. Optimisation of such bioprocesses by adjustment of the expression rate of the heterologous protein to the biosynthetic capacity of the cell metabolism would benefit from an online method for monitoring the metabolic burden. In this study we evaluated the use of a chemical multi-sensor array for this purpose. Fermentations with a recombinant Escherichia coli strain expressing human superoxide dismutase (rhSOD) were monitored by the sensor array. The results of isopropyl-thiogalactopyranoside (IPTG)-induced expression were compared with fermentations with a plasmid-free strain. The overproduction of rhSOD, imposing a high metabolic burden on the plasmid-carrying cells, was distinctly and reproducibly observed by the multi-sensor array. The potential of this non-invasive method of non-specific metabolic burden monitoring is demonstrated by the results of the study. © 2001 Society of Chemical Industry [source] Metabolic Syndrome and Solid-Organ TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2010A. Sharif The metabolic syndrome is proposed as a cluster of known cardiovascular risk factors, interrelated by a common pathophysiological defect, that symbolize a heightened metabolic burden. Advocates of the concept argue that it is a predictor for both diabetes and cardiovascular disease, complications of great importance posttransplantation. The abundant medical literature on the topic is now expanding into the field of transplantation with evidence linking the metabolic syndrome to adverse patient and graft outcomes. Although the implications posttransplantation are significant, controversy surrounds the concept and the topic has not previously been reviewed in the context of solid-organ transplantation. The purpose of this review is to update transplant clinicians with our current understanding of the metabolic syndrome, review the transplantation literature and examine the controversies surrounding the concept. [source] Dietary non-protein energy sources: growth, digestive enzyme activities and nutrient utilization by the catfish jundiá, Rhamdia quelenAQUACULTURE RESEARCH, Issue 3 2010Giovanni Vitti Moro Abstract A study was conducted to evaluate the effect of different dietary carbohydrate to lipid (CHO:L) ratios on growth, digestive enzyme activities and nutrient utilization by jundiáRhamdia quelen (Quoy & Gaimard) an omnivorous catfish native to Latin America. Groups of 40 fingerlings were stocked in 24 tanks and fed eight isonitrogenous (41% crude protein) and isoenergetic (13.5 kJ g,1) casein-based diets for 75 days. Diets had eight CHO:L ratios: 0.3:1, 1.0:1, 2.0:1, 3.4:1, 4.6:1, 5.3:1, 5.6:1 and 6.5:1, and were fed twice a day to apparent satiation. Increasing CHO:L ratio did not significantly affect growth performance. However, the highest apparent net protein utilization was observed in fish fed the 5.3:1 CHO:L diet. No differences were detected among fish on apparent net energy utilization. Whole body fat deposition decreased as dietary CHOL:L ratio increased (P<0.01). The highest fat deposition was observed in fish fed the lowest CHO:L ratio diet. Liver glycogen showed a quadratic response to the increase on dietary carbohydrate concentration, which may suggest that dietary CHO:L ratios above 3.4 can cause metabolic burden for jundiá. Therefore, despite jundiá omnivorous feeding habit, our findings indicate that dietary dextrin concentration above 15.70% (CHO:L=5.3) are not well utilized by jundiá. [source] Generic plasmid DNA production platform incorporating low metabolic burden seed-stock and fed-batch fermentation processes,BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009James A. Williams Abstract DNA vaccines have tremendous potential for rapid deployment in pandemic applications, wherein a new antigen is "plugged" into a validated vector, and rapidly produced in a validated, fermentation,purification process. For this application, it is essential that the vector and fermentation process function with a variety of different antigen genes. However, many antigen genes are unpredictably "toxic" or otherwise low yielding in standard fermentation processes. We report cell bank and fermentation process unit operation innovations that reduce plasmid-mediated metabolic burden, enabling successful production of previously known toxic influenza hemagglutinin antigen genes. These processes, combined with vector backbone modifications, doubled fermentation productivity compared to existing high copy vectors, such as pVAX1 and gWiz, resulting in high plasmid yields (up to 2,220 mg/L, 5% of total dry cell weight) even with previously identified toxic or poor producing inserts. Biotechnol. Bioeng. 2009;103: 1129,1143. © 2009 Wiley Periodicals, Inc. [source] Production of a Secreted Glycoprotein from an Inducible Promoter System in a Perfusion BioreactorBIOTECHNOLOGY PROGRESS, Issue 5 2004Matthew L. Lipscomb The primary advantage of an inducible promoter expression system is that production of the recombinant protein can be biochemically controlled, allowing for the separation of unique growth and production phases of the culture. During the growth phase, the culture is rapidly grown to high cell density prior to induction without the extra metabolic burden of exogenous protein production, thus minimizing the nonproductive period of the culture. Induction of the culture at high cell density ensures that the volumetric production will be maximized. In this work, we have demonstrated the feasibility of overexpressing a reporter glycoprotein from the inducible MMTV promoter in recombinant Chinese hamster ovary (CHO) cells cultured in a high cell density perfusion bioreactor system. Retention of suspension-adapted CHO cells was achieved by inclined sedimentation. To maximize volumetric production of the culture, we have demonstrated that high cell density must be achieved prior to induction. This operating scheme resulted in a 10-fold increase in volumetric titer over the low density induction culture, corresponding directly to a 10-fold increase in viable cell density during the highly productive period of the culture. The amount of glycoprotein produced in this high cell density induction culture during 26 days was 84-fold greater than that produced in a week long batch bioreactor. Long-term perfusion cultures of the recombinant cell line showed a production instability, a phenomenon that is currently being investigated. [source] | ||||||||||