Metabolite production

In order to develop a rational approach to improving rates of metabolite production, it is necessary to consider the fate of the nutrients that are required for its synthesis. However, overcoming the major flux control points within a metabolic pathway may not lead to metabolite overproduction if the energetic consequences of the alteration are unfavourable to the organism. 

It is obvious that rapid metabolite production requires high fluxes of carbon through the metabolic systems responsible for its synthesis. The rate of metabolite production, for a wide range of micro-organisms, has been shown to increase with decrease in... 

In dass 1 (ATP requiring), the rate of metabolite production is limited by the micro-organisms capacity to dissipate energy. 

In dass 2 (ATP generating), the rate of metabolite production, and oxidation state, are inversely related to the growth effidency. 

In dass 3, the rate of metabolite production from a single substrate may be limited by the rate of ATP turnover. Provision of ready made precursors can increase both the metabolite yield (final concentration) and rate of production by decreasing the requirement for ATP turnover during biosynthesis. 

The effect of a particular cultivation environment on a system can be evaluated in terms of biomass (fresh/dry weight, cell number), secondary metabolite production [51,75,89,102,103,106,107] or substrate consumption (e.g. carbon source [57] or oxygen [53,108]). Using the Evan s Blue method to identify non-viable cells. Ho et al. [108] used viable cell density measurements to determine variations in specific growth rate attributable to hydrodynamic stress. 

Taxus cuspidata rotating wall vessel laminar biomass and metabolite productivity growth [106]... 

Stizolobium hassjoo 125-ml shake flasks 140-220 rpm (0.4-1.7 m s- ) secondary metabolite production aggregate size [45]... 

In the interdisciplinary field of biophysics and biotechnology, the bioeffects of electric field have received considerable interest for both fundamental studies on these interaction mechanisms and potential application. However, the effects of pulsed electric field (PEF) on secondary metabolism in plant cell cultures and fermentation processes have been unknown. Therefore, it would be very interesting to find out whether PEF could be used as a new tool for stimulating secondary metabolism in plant cell cultures for potential application to the value-added plant-specific secondary metabolite production. Furthermore, if the PEF permeabilization and elicitation are discovered in a cell culture system, the combination of... 

Griffiths ET, SG Hales, NJ Russell, GK Watson, GF White (1986) Metabolite production during biodegradation of the surfactant sodium dodecyltriethoxy sulphate under mixed-culture die-away conditions. J Gen Microbiol 132 963-972. 

Zhong Y, T Luan, H Zhou, C Lan, N Fung, FY Tam (2006) Metabolite production in degradation of pyrene alone or in mixture with another polycyclic aromatic hydrocarbon by Mycobacterium sp. Environ Toxicol Chem 25 2853-2859. 

Davies, G.K, Simmonds, N.J., Stevens, T.R.J., Grandison, A., Revell, P., Blake, D.R. and Rampton, D.S. (1992a). Mucosal reactive oxygen metabolite production in duodenal ulcer disease. Gut 33, 1467-1472. 

Williams, J.G. and Hallett, M.B. (1989).Effect of sulphasalazine and its active metabolite, 5-aminosalicylic acid, on toxic oxygen metabolite production by neutrophils. Gut 30, 1581-1587. 

Yano, E., Urano, N. and Evans, P.H. (1991). Reactive oxygen metabolite production induced by mineral fibres. In Mechanisms in Fibre Carcinogenesis (eds. R.C. Brown, J.A. Hoskins and N.F. Johnson) pp. 433-438. Plenum, New York. 

Detection by LDMS and structural elucidation of other secondary metabolite products, generated in the host during the onset of the parasite disease, is discussed. These molecules may serve as additional biomarkers for rapid malaria diagnosis by LDMS. For instance, choline phosphate (CP) is identified as the source of several low-mass ions observed in parasite-infected blood samples in addition to heme biomarker ions. The CP levels track the sample parasitemia levels. This biomarker can provide additional specificity and sensitivity when compared to malaria detection based on heme ion signals alone. Furthermore the observed elevated CP levels are discussed in the context of Plasmodium metabolism during its intra-erythrocytic life cycle. These data can... 

Table 9.4 Metabolite production of selected drugs using human cytochrome biocatalysts available from Codexis, Inc"... 

Fig. 4 4-MBC metabolites product ion spectra obtained from MS/MS experiments performed by HPLC-QqTOF-MS/MS. (a) Pr271, (b) Pr287, (c) Pr425 and (d) Pr441. Figure taken from [49]...

Another field of research is the possibility offered by phytochemicals in protecting plants against diseases and pathogens (fungus, bacteria and nematodes). Numerous studies have suggested that plant-pathogen interactions are partially mediated via plant secondary metabolite production, despite the inconsistency revealed by some works on the ability of particular compounds to provide resistance to a specific pathogen. 

GULF TOADFISH, Opsanus tau Isolated hepatocytes acclimatized to 18 or 28°C, then exposed to BaP at 18, 23, or 28°C for about 2 h Isolated gill cells acclimatized to either 18 or 28°C for 3 weeks and exposed for 8 h to 1-100 mg BaP/L at incubation temperatures of 18, 23, and 28°C Dose-dependent increase in metabolite production. 23 Rapid metabolism of BaP independent of temperature Accumulation followed a dose-concentration gradient 24 uptake rate was higher for cells acclimatized to 18°C than those acclimatized to 28°C at all incubation temperatures. When cells were exposed to BaP at the respective acclimatization temperatures, uptake rates were similar... 

Drug metabolite production, microbial biotransformations for, 16 398-399 Drug Price Competition and Patent Term Restoration, 15 686 Drug products... 

See also Biotransformations Microbial oxidations Microbial reductions applications of, 76 396-399 biocatalyst selection in, 76 404-409 biocatalysts in, 76 409-414 for drug metabolite production, 76 398-399 further advances in, 76 414 in hydrolysis, 76 400-401 multiphase reactions in, 777 412-414 scale-up of, 76 414 systematic studies of, 76 398 technique overview for, 76 403-414 timing of substrate additions in, 76 411-412 uses for, 777 400-403 Microbial waxes, 26 203 Microbiocides, triorganotins as, 24 817 Microbiological culture media, agar in, 73 68... 

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