Metabolism culture conditions effect

First, the effects of aerobic and anaerobic culture conditions on toxaphene degradation were studied with washed P. putida cells grown on camphor and incubated with no readily usable carbon source. The radioactivities remaining in water after extraction with n-hexane were used as an indicator of metabolic activity. This was further extracted with ethyl acetate after acidification to divide this "total polar metabolites" fraction into aqueous buffer phase and ethyl acetate phase, i.e., the total polar metabolites reported refer to summation of the aqueous buffer and ethyl acetate soluble phases (Table 4). All radioactivities have been corrected by zero time controls and autoclaved 8 hr controls are included in each experiment. 

T cell activation results in the proliferation of primary T cells in culture, which can be measured directly by monitoring the rate of DNA synthesis. Metabolic incorporation of tritiated thymidine ( H-TdR) into cellular DNA is the most commonly used method, because it is highly sensitive and allows detection of poorly proliferating cells such as primary T cells. In addition, the H-TdR incorporation assay is time and cost effective and offers the possibility to screen the effects of several inhibitors, culture conditions, stimulations, etc. in a single 96-well plate. 

Lebeau, M. C., Jung-Testas, 1., and Baulieu, E. E. (1999). Intracellular distribution of a cytoplasmic progesterone receptor mutant and of immunophilins cyclophilin 40 and f KBP59 Effects of cyclosporin A, of various metabolic inhibitors and of several culture conditions. J. Steroid Biochem. Mol. Biol. 70,219-228. 

Hairy roots are not as readily manipulated by altering culture conditions or pH as are suspension cultures. However, the effect of temperature on growth and hyoscyamine production in transformed root cultures of Datura stramonium has been demonstrated by Hilton and Rhodes [86]. Another way to enhance the secondary metabolite accumulation of hairy roots is the addition of precursors and/or metabolic intermediates to the growth medium. The addition of (R,S)- phenyllactic acid increased significantly the accumulation of hyoscyamine and scopolamine in the hairy root culture of Datura Candida x D. aurea [72]. 

Tholozan, J.-L., Membr6, J.-M., Kubaczka, M. (1996). Effects of culture conditions on Pectinatus cerevisiiphilus and Pectinatus frisingensis metabolism a physiological and statistical approach. Journal of Applied Bacteriology, 80, 418 24. 

C. Effect of Growth and Culture Conditions on Ganglioside Metabolism... 

Culture Conditions and Selection. The effects of other culture parameters have recently been reviewed (Mora, 1973). In general, variation of culture media, pH, and serum had little or no effect on ganglioside metabolism. Contact-inhibited cells grown under crowded conditions for a number of passages whereby the cells became less... 

Another aspect of designing a C. ele [ans screen is whether to feed the worms with live or dead bacteria. Worms prefer feeding on living bacteria. We have verified that the bacteria in the below described C. ele [ans liquid culture conditions do not grow, as there are no nutrients for bacterial growth in the media. However, it is likely that bacteria will metabolize some of the library compounds. Furthermore, some library compounds could affect the bacteria, causing potential indirect effects on the worms [2], The most effective way to prepare dead bacteria is by gamma irradiation with... 

When excess substrate interferes with growth and/or product formation. One example is the production of baker s yeast. It is known that relatively low concentrations of certain sugars repress respiration and this will make the yeast cells switch to fermentative metabolism, even under aerobic conditions. This, of course, has a negative effect on biomass yield. When maximum biomass production is aimed at, fed batch cultures are the best choice, since the concentration of limiting sugar remains low enough to avoid repression of respiration. 

Careful empirical selection of the expression platform for carotenogenesis has included selection of the best strains for stability and degree of accumulation and the selection of compatible drug-resistance combinations and low copy number polycistronic plasmids to enhance product accumulation by decrease of metabolic burden." 5 Matthews and Wurtzel discussed culture and induction conditions - that have been explored in most studies. Most efforts to engineer carotenoid biosynthesis in E. coli focused on the genes and enzymes of the pathway and had a modest effect on improved accumulation. For example, substitution and over-expression of a GGPPS that uses IPP directly (discussed in... 

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