Extract assays

B) at the indicated stages, and the PGl, PG2, and total PG activities were determined by differential heat inactivation. Each time point is the average of at least two separate extractions assayed in duplicate. The developmental stages are MG, mature green Br, breaker stage, (time of first external color development) and +2, +5, +7, and +10 are days after breaker. 

Assays with Crude Extracts. Assays of the activities present in crude culture extracts were useful to indicate the enzymes available for recovery. Extracts from L. edodes typically exhibited a wide range of enzyme activities present in quantities apparently sufficient for isolation and characterization (Table I). 

Of these three basic approaches, the aqueous acid extraction TBA test (see Basic Protocol 1) may be considered the better assay for estimating the malonaldehyde content in food. In this technique, the food sample is not subjected to heat and less sample autoxidation takes place the malonaldehyde content of the sample should not be overestimated. For this reason, the extraction assay has been listed as the basic protocol to determine TBA values of foodstuffs. 

The operation of the preprocessor is shown schematically in Figure 1. There are five basic steps o Select crude assay data o Build and report input tables o Generate crude data o Generate process data o Build and access LP data tables In the first step, the preprocessor accesses the disc file which contains all of Sun Petroleum Products Company s crude assays. The preprocessor extracts assay data for those crudes which the user has identified by card input as part of the base crude mix or to be made available to the LP model as an incremental refinery feed. The user can identify up to ten crudes any five of which can be designated as incremental. 

Limit of quantification of this method was 5 ng/L. The method was linear from 5 to 250 ng/L. The accuracy (8%) and precision (CV below 13%) we observed with this protocol using the SPME procedure are very similar to those obtained with the traditional liquid-liquid extraction assays. 

The most serious problem encountered with the assay system is a quantitative variability that is, a particular set of extracts assayed under identical conditions in separate assays may give figures which are quantitatively different. The reason for this is unknown. The relative cyclic AMP activity in the extracts is the same that is, when sample B contains twice as much cyclic AMP as sample A on day 1, it will also contain twice as much on day 2. However, the absolute values of cyclic AMP may vary. 

Residue remaining after methanol extraction assay by combustion analysis. 

Xu Y, Willson KJ, Musson DG, Strategies on efficient method development of on-line extraction assays for determination of MK-0974 in human plasma and urine using... 

Extract assays are conducted by cultivating a monolayer of cells for 24 h in a standard media. An extract of a biomaterial is taken, placed in fresh medium, and used to replace the standard medium after 24 h. The cells are incubated for 24 to 72 h, after which time the changes in monolayer density due to cell necrosis are noted. The reactivity grade is assigned based on the percentage of affected cells. 

The extract dilution type of cell culture assay requires a solvent extraction of the biomaterial under consideration and testing of this extract, most commonly at various dilutions, for evidence of cytotoxicity and cellular interaction. This type of cell culture assay finds its most common use in providing information for regulatory compliance. As identified in the preceding Materials for Medical Devices section and in Table 1, low-molecular-weight extractables are of concern regarding biocompatibility. The extraction assay, carried out with a series of solvents that are hydrophilic and hydrophobic, permits examination of the potential cytotoxicity of extracts and the identification of materials within a biomaterial that may be cytotoxic. These types of assays ultimately permit identification and characterization of cytotoxic materials within biomaterials or the lack of cytotoxicity, as well as providing correlation with in vivo assays such as sensitization, irritation, intracutaneous (intradermal) reactivity, and other tests where the in vivo injection of extracts is required. 

Crude Extract Assay In Rg. 3, the response of crude extract fractions to RuBP is shown. One milli-unit of RuBisCO is that amount which catalyzes the RuBP-dependent fixation of 1.0 nmole of C02toinute at 30° C. Specific activity is expressed as milli-units/mg protein. As evident, both mutant enzymes were similarly saturated with RuBP in the 39-52 mM range. In contrast, wild-type RuBP carboxylase saturated in a lower concentration range of 13-26 mM. Quantitative comparisons were not possible because the Km for RuBP markedly increases with increasing ionic strength. The major effect of Ae substitution of leu and lys for arg at position 292 was, however, upon the specific activity of the enzymes. 

Feedback inhibitor Allosteric activator Specific activity (crude extract) Assay procedure... 

The extraction of the alkaloids from cinchona is difficult and, as the bark contains colouring matter and substances which cause emulsification, the quantitative determination is not easy. A continuous extraction assay is needed, such as that of Self and Corfield this is probably the most satisfactory process. 

Many other solvents and mixtures of solvents are used in base-extraction assays but it is difficult to generalise since the choice of a particular system may be due to personal preference or experience. 

The tested acetolactate synthase (ALS) was from pea (pisum sativum). The ALS extraction, assay protocols, and the procedure of in vitro ALS assay followed the literature [41]. 

Table 7.8 Morphological qualitative graded scale for test on extracts assay (International Orgamzation for Standardization. 2009)...

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