Synthesis measurements

Male and female Fischer 344 rats and B6C3Fi mice were fed di(2-ethylhexyl) phthalate for up to 13 weeks (David et al., 1999). In rats fed 12 500 ppm di(2-ethylhexyl) phthalate, there was an increase in hepatocyte replicative DNA s mthesis (measured after continuous bromodeoxyuridine administration (osmotic pump) for three days before sampling) after one week (but not after two or 13 weeks) and an increase in hepatic peroxisomal [3-oxidation activity after one, two and 13 weeks administration. In mice fed 10 000 and 17 500 ppm di(2-ethylhexyl) phthalate, there was no increase in hepatocyte replicative DNA synthesis (measured after continuous bromodeoxyuridine three days before sampling) after one, two or 13 weeks of administration, but there was an increase in hepatic peroxisomal 3-oxidation activity after one, two and 13 weeks administration. In mice fed 1000 ppm di(2-ethylhexyl) phthalate, there was no statistically significant increase in hepatic peroxisomal 13-oxidation activity after one, two or 13 weeks administration (bromodeoxyuridine labelling was not evaluated at this lower dietary concentration of di(2-ethylhexyl) phthalate). 

The requirements for epithelial cells are somewhat different (Reiss and Dibble, 1988). Mouse keratinocytes (MK-1 cells) enter a GO-phase within 24 h when confluent cultures are fed a serum-free, low Ca2+ (< 0.1 mM) medium supplemented with insulin, transferrin and sodium selenate (see 5.8). Addition of EGF (10 ng/ml) causes cells to enter S-phase after 10-12 h although the percentage of cells responding is not known. Insulin is not essential for this effect but apparently leads to a threefold increase on the rate of DNA synthesis measured 22-24 h after addition of EGF. TGF/ (100 pM) completely abolishes the effect of EGF. 

On careful extraction (i.e., avoiding proteolysis, inactivation by pheno-lics), from the plant tissue, the maximal activities measured in vitro (i.e., in the presence of activators at optimum pH) should at least equal the rates of starch synthesis measured in vivo. 

The aim of the present book is to offer a comprehensive, up-to-date survey of the numerous facets of the subject. As it falls in the Applied Physics series, the book focuses especially on basic chemical and physical concepts. We have, as much as possible, stressed clarity over completeness, even avoiding some obscuring aspects that, although important, might be too specialized and discourage the reader. In that case, of course, the references help the reader who needs more detailed information to find it easily. On the other hand, all the experimental aspects, original techniques, and specific methods of synthesis, measurement, control, and analysis have been developed thoroughly. 

Synthesis measured using the constant infusion of l C-proline and degradation calculated as the difference between the rate of synthesis and the rate of protein accretion. From Laurent et al. (14). 

Values are mean SEM. For cytoheme ab synthesis, animals are decapitated on day 0 and injected with the designated dose of Bld-HrTH daily on days 2,3 and 4 and cytoheme ab synthesis measured on day 4 (60, ). For trehalose synthesis, animals are decapitated on day 5 and the designated dose of Bld-HrTH injected on day 6 at time zero and the hemolymph carbohydrate measured 2 hr later. 

The quest for superconductivity at always higher temperature has been a constant motivation in the material science research over the past quarter of the century. A well known example is the huge amount of work which has been invested in the synthesis, measurements and processing of intermetallic compounds belonging to the A-15 family of type II superconductors. These compounds V,Si [I] and NbjSn [2] are still at present the materials mostly used when superconductivity comes to applications [3]. 

Shefer, S., Gheng, F. W., Hauser, S., Batta, A. K., and Salen, G., Regulation ofbile acid synthesis. Measurement of cholesterol 7 -hydroxylase activity in rat liver microsomal preparations in the absence of endogenous cholesterol. J. Lipid Res. 22, 532-536... 

In considering that vitamin C is an important dietary antioxidant, studies were conducted on the effects of the addition of vitamin C upon selected actions of L-tryptophan and on its ability to bind to a specific hepatic nuclear receptor for L-tryptophan and to stimulate protein synthesis.190 The results indicated that the addition of ascorbic acid at 106 to 10-4 M to hepatic nuclei in vitro inhibited 3H-tryptophan binding to the nuclei and nuclear envelopes. Also, the in vivo administration of ascorbic acid before or along with L-tryp-tophan decreased the tryptophan-induced stimulation of hepatic protein synthesis (measured in vitro using microsomes). 

This indicates that the apparent dissociation constants for benalaxyl and metalaxyl are similar. The binding site has a lower affinity for cyprofuram and oxadixyl, which is in agreement with the lower activity of these compounds against RNA synthesis measured as [ H]uridine incorporation by mycelium (121. 

Two assays were developed that measure the potency of the FGF-4 transgene carried by Ads FGF-4. In the first case, a one-step growth-promotion assay is conducted on normal, human retinal pigment epithelial cells (ARPE-19). The assay measures metabolic activity (Alamar blue dye metabolism) following infection of ARPE-19 cells with a serial dilution of the virus. The increase in metabohc achvity was measured in relation to a mock-infected control. This increase correlates with FGF-4 produchon determined by an FGF-4 ELISA, increased de-novo DNA synthesis measured by BrdU incorporation, and an increase in cell number. This procedure is therefore an appropriate in-vitro efficacy measure, indicating that the FGF-4 transgene product is biologically active. 

The test reactor was a 13 mm i.d. quartz tube fitted to a process unit equipped with gas supplies, flow and temperature controllers, a furnace, and a gas chromatograph with appropriate columns and detectors. The sample was loaded into the reactor, purged and/or reduced and heated to the test temperature (200-250°C). With the feed gas (C2H4 and O2, CO2 and H2, or CO and H2) flowing, conversion and product composition were measured. Conversions were maintained as low as possible so that differential rates could be determined. In the case of Fischer-Tropsch synthesis, measurements were made at higher conversions to check selectivities. 

The first parameter considered is Vj, which measures the maximum rate at which PER is degraded. When all other parameter values remain as in fig. 11.7, numerical simulations show that sustained oscillations occur in a window bounded by two critical values of this parameter, close to 0.45 and 2.6, respectively (in p-M/h if a scale of xM is chosen for concentrations). In this interval of values, the period of the oscillations increases from a value close to 19.7 h up to a value close to 64 h. The period range in the window of values depends on other parameters. Thus, for a larger value of the rate of protein synthesis measured by ks, the period varies as a function of from 15.9 to 62.1 h (fig. 11.9). 

Undifferentiated cultures at 80-90 i confluence treated 2-24 hr with chlorpyrifos (0.5-50 pg/nil 1.4-140 pAf) in medium with yk serum some cultures at 70-80 S confluence diftcrenciaied 48 hr with dexamethasone and treated with 50 pg/ml chlorpyrifos DNA and protein synthesis measured, as Well as adcnyl cyclase, Ap-I binding, Sp binding, and ROS generation. 

In conclusion, it is clear that protein synthesis measurements can reveal novel features of the growth and physiological adaptations of ectotherms. Further work should considerably improve the estimates of the contribution that protein synthesis makes to total oxygen consumption the indications are that protein synthesis will turn out to be of major significance in ectotherms. Knowledge of protein synthesis rates should also provide a sound basis for investigations into net protein accretion and its manipulation through nutritional and other means. 

In Summerfelt RC, Hall GE (eds) Age and growth of fish. Iowa State Univ Press, Ames Aoyagi Y, Tasaki I, Okumura J-I, Muramatsu T (1988) Energy cost of whole-body protein synthesis measured in vivo in chicks. Comp Biochem Physiol 91A 765-768 Ashford AJ, Pain VM (1986) Effects of diabetes on the rates of synthesis and degradation of ribosomes in rat muscle and liver in vivo. J Biol Chem 261 4059-4065 Bates PC, Millward DJ (1981) Characteristics of skeletal muscle growth and protein turnover in a fast-growing rat strain. Br J Nutr 46 7-13... 

A role for FLAP in LT synthesis is further supported by an analysis of the cellular distribution of the protein (Table 1). Until recently, the expression of 5-LOX and LT synthesis was believed to be limited to cells of the myeloid lineage. However, studies have now demonstrated that while 5-LOX is expressed to highest levels in myeloid cells, the enzyme is also expressed in a variety of extra-haematopoietic cell types. In every cell type where 5-LOX has been detected and LT synthesis measured, FLAP has also been detected. While 5-LOX and FLAP are usually co-expressed in cells, there are a few cell types where FLAP has been detected in the absence of 5-LOX. For example, FLAP expression has been reported in U-937 histiocytic lymphoma cells [28,38], Caco-2 and HT-29 colon epithelial cells [31], and lymphoblastic T cell lines [28,35,37], even though 5-LOX was undetectable in these studies. The expression of FLAP in the absence of 5-LOX suggests that FLAP may be involved in a biological process in addition to LT synthesis, although what this process may be remains unclear. 

This is the process of establishing the time taken to perform a specified task by a qualified worker operating at a defined level of performance. Both of these measures are difficult to define, and hence, the process is quite controversial. Nevertheless, basic procedure involves three distinct phases -analysis, measurement, and synthesis. Measurement techniques like time study and analytical estimating usually demand direct observation. An understanding of work-time consequences is unquestionably crucial to job design. 

When this work was begun in 1966, conditions were not known for obtaining reasonable stimulation of cell-free peptide synthesis with E. coU DNA. The systems in use at that time were effective only when employed in conjunction with T-phage DNA [119,120]. Since the lac operon could be obtained only in E. call or related lysogenic phage DNA s, the first task was to develop a suitably responsive system. This was accomplished by varying the components and their concentration to achieve a maximum of E. call DNA-directed peptide synthesis measured by the incorporation of C-leucine. Conditions were ultimately found where coli DNA stimulated abut 0.7 m/imole of leucine incorporation per milligram of total protein in the cell-free system [121]. 

The height of each bar represents the mean and tiie brackets the 95% confidence limit. Each vessel contained 5 ml Krebs-Rir er bicarbonate buffer and approximately 0,3 to 0.5 g slices, The slices were incubated for 1 hour in buffer alone, and then transferred to fresh buffer alone or buffer containing 10 jug LH/5 ml for the second incubation. After 15 minutes, one set of slices was analyzed for cyclic AMP, The other set of slices was incubated for 2 hours and steroid synthesis measured,... 

Fig. 19. Effect of internal concentration of free glutamic acid on the rate of protein synthesis (measured by the increase in combined glutamic acid of the cells) in Staph, aureus. Broken lines indicate internal concentration of free glutamic acid continuous lines, protein synthesis open points, cells pretreated with glucose and glutamic acid solid points, cells pretreated with glucose only. (Gale, 1951b.)...

---