Incubations conditions

Screening is usually carried out with liver microsomes from humans, rats, mice, dogs and monkeys and liver S9 fraction from aroclor 1254-induced rats. The incubation is typically mn with a volume of 0.2-1. OmL in a microcentrifuge or a glass tube. Different incubation conditions are used for CYP and UGT reactions. The incubation mixture for formation of oxidative metabolites and/or GSH conjugates contains ... 

Soars, M.G., Ring, B.J. and Wrighton, S.A. (2003) The effect of incubation conditions on the enzyme kinetic of UDP-glucuronsyltransferases. Drug Metabolism and Disposition The Biological Fate of Chemicals, 31, 762-767. 

Basal respiration Variable depending on incubation Conditions. Often in the range of 5-40 jig CO2-C g 1 day-1 Quantity of organic C released as C02 during an aerobic laboratory incubation. A measurement of the activity (respiration rate) of the soil microbial community. 

Fig. 5.4. LH secretion from hemipituitaries from ovariectomized rats treated during 3 d with oil (0.2 ml), estradiol benzoate (EB, 25 xg), or tamoxifen (TX, 3 mg) and incubated for 3 h with medium alone, 17/S-estradiol (E2, 10"8 M), or TX (10 7 M), in response to two consecutive GnRH challenges (10-8 M, for 15 min) at indicated time periods. Values of LH secretion from hemipituitaries of oil- and EB-injected ovariectomized rats incubated with medium alone, E2, or TX (24 hemipituitaries), and from hemipituitaries of TX-injected rats incubated with medium alone or TX (16 hemipituitaries) are represented together, as no effect of the incubation conditions was observed. Values of LH secretion from hemipituitaries of TX-injected ovariectomized rats incubated with E2 are the mean of 8 half glands. P < 0.01 versus non-EB-treated rats (modified from Sanchez-Criado et al. J Endocrinol 186 43-49,2005)...

The development of biological tools to support DDI studies has paralleled the development of bioanalytical techniques. To better understand in vitro-in vivo (IVIV) correlations, the effects of differences in enzyme preparations and incubation conditions must be understood. Differences between enzyme preparations include nonspecific binding, the ratio of accessory proteins (cytochrome b5 and reductase) to CYPs and genetic variability differences in incubation conditions include buffer strength, the presence of inorganic cations and solvent effects. Understanding how biology influences enzymatic activity is crucial to accurate and consistent prediction of the inhibition potential. 

During a 30 minute incubation period, low levels of aldrin epoxidation (30-150 picomoles dieldrin/mg protein) were measured compared to those observed using enzyme sources such as aquatic Trichoptera Limnephilus sp. gut homogenates (1 pmole/mg protein 28) or rat liver homogenates (3000 pmoles/mg protein unpublished) under similar incubation conditions. Anisole metabolism based upon substrate disappearance was detectable but less than 5 picomoles/mg protein were transformed during the incubation period. Characteristics of the enzyme system are incompletely described owing to the low and variable levels of activity which have been obtained. 

Several modifications of incubation conditions have neither stabilized the system nor enhanced activity. Acetone and methanol have been used as substrate carriers without affecting activity. Similarly, addition of NADH to the incubation media did not effect epoxidation. The enzymatic nature of the system has been confirmed by use of heat treated homogenates (100 C, 1 min). Incubation temperatures of 8, 20, and 30 resulted in progressively greater epoxidation rates and provided no evidence of heat lability. Thus, at this time it is not possible to identify a superior enzyme source for comparative studies in spite of the fact that in vivo measurements indicate oxidative metabolic activity in living mussels. 

Incubation Conditions pmoles 3-hydroxybenzo(a)pyrene formed/min/nmol cytochrome P-448 % Maximum Activity... 

The hepatic microsomes were aliquots from pools of 10 control or pretreated fish that were also used for the partial purification of various forms of Cytochrome P-450 9,10-D, BP-9,10-dihydrodiol 4,5-D, BP-4,5-dihydrodiol 7,8-D, BP-7,8-dihydrodiol Q + E, BP-1,6-, -3,6-, and -6,12-quinones and BP-4,5-oxide 9-OH, 9-hydroxy-BP 3-OH, 3-hydroxy -BP. The DBA-dosing schedule and incubation conditions are described in Materials and... 

Incubation Conditions. The incubation mixtures consisted of the cell preparation, with or without a flavin cofactor (FMN,... 

Attention to avoid the lack of efficiency, new cultures of M. isabellina should be used and a careful control of incubation conditions (temperamre, pH and medium) is necessary. 

Enzyme Incubation conditions Immobilized Units (%) Active Units (%)... 

The incubation conditions for trypsin and pepsin were chosen after preliminary tests showed that measurable amounts of collagen were released into the incubation solutions. In trypsin incubations, degradation is fastest on day 1 and decreasing in velocity thereafter. Slices digested extensively by pepsin were fragile. Infermittent changes of pepsin solutions were therefore avoided. 

The effect of sequential chemoattractant exposure on neutrophil F-actin polymerization responses may also be evaluated with this technique. The data presented in Fig. 3 were collected from an experiment in which neutrophils were exposed to 10 M LTB4 for 5 min and then exposed to 10 M FMLP for 5 min ( ), and compared with neutrophils exposed only to 10 M FMLP under identical incubation conditions (O). 

The results given below were collected in a study of decomposition in skipjack tuna (Katsuwonus pelamis) under controlled incubation conditions and were described in part previously (, 25). Skipjack was chosen as the test species for this investigation because ... 

In assessment of optimal incubation conditions it is advisable, as is frequently done in work with less costly substrates, to measure the activities as a function of the parameter considered at two time points along the velocity-time curves. A survey of available techniques for assaying conjugated bilirubin (Section 4) shows that the possibilities of miniaturization, e.g., by reducing the total volumes of the incubations mixtures without changing the relative concentrations of their components, have seldom been exploited. 

Incubation conditions. Preliminary trials indicated that incubation at 20 °C for 72 h in darkness is optimal. This relatively low temperature allows adequate wheat growth while retarding mold development. 

Incubation conditions, timing of the addition of drug or drug concentrations that are insufficient to exert cellular effects. 

Figure 7. Elution profile of protein, radioactivity, and thiocyanate from a Sepha-dex G-25 column of a reconstituted monooxygenase system from rat liver that had been incubated with [ 5] parathion followed by incubation with cyanide. The incubation conditions and analytical procedures were as described in Figure 7 except that the labeled protein was incubated with lOmM sodium cyanide for 3 h at room temperature prior to being applied to the Sephadex column (20).

Incubation conditions should be established whereby there is a linear relationship between time and product formation and between amount of enzyme and product... 

Other cultivation strategies which were followed were the enrichment of picoplankton bacteria under a wide range of nutrient and incubation conditions [33], and isolation of biofilm bacteria that had grown in situ on artificial surfaces. 

Every 4 months, open a new ampoule and subculture to TSB. The incubation conditions for this organism are 24 hours at 32 2°C. Subculture from the TSB to (TSA) slopes (stock slopes) and concurrently plate onto a TSA plate to check for purity. 

---