The recent development of dissolution dynamic nuclear polarization (DNP) gives NMR the sensitivity to follow metabolic processes in living systems with high temporal resolution. In this article, we ...apply dissolution DNP to study the metabolism of hyperpolarized U- super(13)C, super(2)H sub(7)-glucose in living, perfused human breast cancer cells. Spectrally selective pulses were used to maximize the signal of the main product, lactate, whilst preserving the glucose polarization; in this way, both C sub(1)-lactate and C sub(3)-lactate could be observed with high temporal resolution. The production of lactate by T47D breast cancer cells can be characterized by Michaelis-Menten-like kinetics, with K sub(m)=3.5 plus or minus 1.5mm and V sub(max)=34 plus or minus 4 fmol/cell/min. The high sensitivity of this method also allowed us to observe and quantify the glycolytic intermediates dihydroxyacetone phosphate and 3-phosphoglycerate. Even with the enhanced DNP signal, many other glycolytic intermediates could not be detected directly. Nevertheless, by applying saturation transfer methods, the glycolytic intermediates glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate, phosphoenolpyruvate and pyruvate could be observed indirectly. This method shows great promise for the elucidation of the distinctive metabolism and metabolic control of cancer cells, suggesting multiple ways whereby hyperpolarized U- super(13)C, super(2)H sub(7)-glucose NMR could aid in the diagnosis and characterization of cancer in vivo. Copyright copyright 2013 John Wiley & Sons, Ltd. New ways of monitoring glycolytic processes in live breast cancer cell cultures based on perdeuterated hyperpolarized glucose are demonstrated (a). Lactate and other intermediates are then visible on T47D cells maintained viable in a custom-made continuous bioreactor (b). Metabolic characteristics of other 'invisible' intermediates can also be gathered from saturation transfer experiments (c).
In a liquid-liquid interface bioreactor, fungal cells locate in a hydrophilic polyacrylonitrile microsphere layer on an aqueousaorganic interface. In this article, effects of hydrophobicity of the ...interface on n-decane hydroxylation activity of Monilliera sp. NAP 00702 was examined. (-)-4-Decanol production was significantly enhanced to 132% by addition of polytetrafluoroethylene.
Abstract
Various processes that have been successfully developed for wastewater treatment (treatment of industrial wastes/effluents) have been surveyed with special reference to biological treatment ...including design of bioreactors. Limitations of each process, design and performance characteristics of different kinds of bioreactors developed starting from stirred tanks to packed bed, fluidized bed, moving bed, semifluidized bed, inverse fluidized bed, sludge bed/sludge blanket and downflow stationary fixed film bioreactors have been highlighted. Utilization of membrane-based technology and liquid phase oxygen technology in wastewater treatment has also been analyzed. Both aerobic and anaerobic processes have been considered and possibilities of clubbing waste treatment with waste utilization (production of valuable products from waste streams) have also been surveyed and scrutinized.
The applicability of anaerobic baffled reactor (ABR) was investigated for the treatment of acidic (pH 4.5-7.0) wastewater containing sulfate (1000-2000 mg/L) and Zn (65-200 mg/L) at 35 degreeC. The ...ABR consisted of four equal stages and lactate was supplemented (COD/SOsub4super2- = 0.67) as carbon and energy source for sulfate reducing bacteria (SRB). The robustness of the system was studied by decreasing pH and increasing Zn, COD, and sulfate loadings. Sulfate-reduction efficiency quickly increased during the startup period and reached 80% within 45 days. Decreasing feed pH, increasing feed sulfate and Zn concentrations did not adversely affect system performance as sulfate reduction and COD removal efficiencies were within 62-90% and 80-95%, respectively. Although feed pH was steadily decreased from 7.0 to 4.5, effluent pH was always within 6.8-7.5. Over 99% Zn removal was attained throughout the study due to formation of Zn-sulfide precipitate.
Seven bioreactor landfill simulators (mixed gravel, gravel in layers, and controls without gravel with two levels of compaction, i.e. normal and lower density) were used to investigate the effect of ...different hydraulic conditions on the waste stabilisation process. The simulators with mixed gravel showed a higher degree of waste stabilisation towards the end of the experiment due to higher moisture content, whereas the other simulators were prone to clogging thus reducing the overall treatment effectiveness. Moreover, reaching neutral pH levels seemed to be the "driving force" that enhanced physical, chemical and biological processes contributing to waste stabilisation in the simulators with mixed gravel. After one year of operation, the residues of the different simulators were very close to achieve a final storage quality status comparable to the waste acceptance criteria for inert waste of the European landfill directive.
Pharmaceutically active compounds (PhACs) and drugs of abuse (DAs) are two important groups of emerging environmental contaminants that have raised an increasing interest in the scientific community. ...A number of studies revealed their presence in the environment. This is mainly due to the fact that some compounds are not efficiently removed during wastewater treatment processes, being able to reach surface and groundwater and subsequently, drinking waters.
In designing a tissue engineering strategy for cartilage repair, selection of both the bioreactor, and scaffold is important to the development of a mechanically functional tissue. The hydrodynamic ...environment associated with many bioreactors enhances nutrient transport, but also introduces fluid shear stress, which may influence cellular response. This study examined the combined effects of hydrogel cross-linking and the hydrodynamic environment on early chondrocyte response. Specifically, chondrocytes were encapsulated in poly(ethylene glycol) (PEG) hydrogels having two different cross-linked structures, corresponding to a low and high cross-linking density. Both cross-linked gels yielded high water contents (92% and 79%, respectively) and mesh sizes of 150 and 60 A respectively. Cell-laden PEG hydrogels were cultured in rotating wall vessels (RWV) or under static cultures for up to 5 days. Rotating cultures yielded low fluid shear stresses (0.11 Pa) at the hydrogel periphery indicating a laminar hydrodynamic environment. Chondrocyte response was measured through total DNA content, total nitric oxide (NO) production, and matrix deposition for glycosaminoglycans (GAG). In static cultures, gel cross-linking had no effect on DNA content, NO production, or GAG production; although GAG production increased with culture time for both cross-linked gels. In rotating cultures, DNA content increased, NO production decreased, and overall GAG production decreased when compared to static controls for the low cross-linked gels. For the high cross-linked gels, the hydrodynamic environment had no effect on DNA content, but exhibited similar results to the low cross-linked gel for NO production, and matrix production. Our findings demonstrated that at early culture times, when there is limited matrix production, the hydrodynamic environment dramatically influences cell response in a manner dependent on the gel cross-linking, which may impact long-term tissue development. Biotechnol. Bioeng. 2009; 102: 1242-1250.
Objectives: Multiple types of bioreactors with perfusate are used for the culturing and examination of cell cultures and their interaction with the perfusion media. In case of use with full blood or ...corpuscular blood components as perfusion medium, the traumatization of the necessary pump is a crucial aspect The usual roller pumps create unacceptable trauma and activation, due to the low priming volume and the multiple exposition of the blood particles to the pump shear. Methods: Multiple types of bioreactors with perfusate are used for the culturing and examination of cell cultures and their interaction with the perfusion media. In case of use with full blood or corpuscular blood components as perfusion medium, the traumatization of the necessary pump is a crucial aspect. The usual roller pumps create unacceptable trauma and activation, due to the low priming volume and the multiple exposition of the blood particles to the pump shear. Results: First tests showed a hemolysis increase for the MP of only 1.4 compared to 25.3 mg/dL/hour for the RR.ICAM-1, HLA-DR and CD11 b were moderately activated by MP, but massively by RP. In contrast to RP, MP did not cause the expression of procoagulatory tissue factor on monocyte surface. Conclusions: A minipump with very cheap disposable components could be developed, which caused very low blood trauma In first tests.
Objectives: The post-printing tissue maturation requires development of new type of perfusion bioreactor. The rational design behind such bioreactor, especially the level of porosity and distance ...between minitubes must be based on systematic mathematical modeling and computer simulation of interstitial flow. The proposed novel irrigation dripping tripled perfusion bioreactor will enable to 'buy' time until the 'built in' intraorgan branched vascular system will mature enough for initiation of intravascular perfusion. Methods: Fick's formula has been used to estimation diffusion coefficient for oxygen and small molecular weight tracers such as dextran or bovine serum albumin. It was assumed that hydrogel has isotropic properties. Mathematical model for diffusion and diffusion enhanced by convection has been developed. Computer simulation of diffusion gradient has been explored using color coding of trace molecule concentration. Results: Mathematical modeling has shown that with increasing minitube porosity the diffusion distance will also increase. The diffusion with additional convection will increase distance between porous minitubes. Thus, rational design of irrigation dripping tripled perfusion bioreactor must have combination of proper level of minitube porosity and maximal possible and biologically acceptable distance between minitubes. Computer simulation of interstitial flow and estimated parameters for rational design of perfusion bioreactor have been confirmed experimentally by analysis of diffusion of tracer molecules from porous needle placed in different type of hydrogels. It has been also demonstrated that during tissue maturation the diffusion and interstitial flow in bioprinted tissue construct will be gradually reduced. Conclusions: Mathematical modeling and computer simulation have been used to estimate proper design parameters. Thus, it has been demonstrated that with implementation of rational design based on mathematical modeling and computer simulation development of irrigation dripping tripled perfusion bioreactor is a realistic goal.
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