In recent years, metabolomics developed to an accepted and valuable tool in life sciences. Substantial improvements of analytical hardware allow metabolomics to run routinely now. Data are successfully used to investigate genotype-phenotype relations of strains and mutants. Metabolomics facilitates metabolic engineering to optimise mircoorganisms for white biotechnology and spreads to the investigation of biotransformations and cell culture. Metabolomics serves not only as a source of qualitative but also quantitative data of intra-cellular metabolites essential for the model-based description of the metabolic network operating under in vivo conditions. To collect reliable metabolome data sets, culture and sampling conditions, as well as the cells' metabolic state, are crucial. Hence, application of biochemical engineering principles and method standardisation efforts become important. Together with the other more established omics technologies, metabolomics will strengthen its claim to contribute to the detailed understanding of the in vivo function of gene products, biochemical and regulatory networks and, even more ambitious, the mathematical description and simulation of the whole cell in the systems biology approach. This knowledge will allow the construction of designer organisms for process application using biotransformation and fermentative approaches making effective use of single enzymes, whole microbial and even higher cells.

A method has been developed for quantification of 20 amino acids as well as 13 (15)N-labeled amino acids in barley plants. The amino acids were extracted from plant tissues using aqueous HCl-ethanol and directly analyzed without further purification. Analysis of the underivatized amino acids was performed by liquid chromatography (LC)-electrospray ionization (ESI) tandem mass spectrometry (MS-MS) in the positive ESI mode. Separation was achieved on a strong cation exchange column (Luna 5micro SCX 100A) with 30 mM ammonium acetate in water (solvent A) and 5% acetic acid in water (solvent B). Quantification was accomplished using d (2)-Phe as an internal standard. Calibration curves were linear over the range 0.5-50 microM, and limits of detection were estimated to be 0.1-3.0 microM. The mass-spectrometric technique was employed to study the regulation of amino acid levels in barley plants grown at 15 degrees C uniform root temperature (RT) and 20-10 degrees C vertical RT gradient (RTG). The LC-MS-MS results demonstrated enhanced concentration of free amino acids in shoots at 20-10 degrees C RTG, while total free amino acid concentration in roots was similarly low for both RT treatments. (15)NO(3) (-) labeling experiments showed lower (15)N/(14)N ratios for Glu, Ser, Ala and Val in plants grown at 20-10 degrees C RTG compared with those grown at 15 degrees C RT.

In this chapter, we describe a method for quantification of 20 proteinogenic amino acids as well as 13 (15)N-labeled amino acids by liquid chromatography-mass spectrometry without the need for derivatization and use of organic solvents. Analysis of the underivatized amino acids is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) in the positive ESI mode. Separation is achieved on a strong cation exchange (SCX) column (Luna 5 μm SCX 100 Å) with 30 mM ammonium acetate in water (A) and 5% acetic acid in water (B). Quantification is accomplished by use of d(5)-phenylalanine as internal standard achieving limits of detection of 0.1-3.0 μM. The method was successfully applied for the determination of proteinogenic and (15)N-labeled amino acids in plant extracts.

This paper presents the results of a study of the slip velocity of gasesrising through liquids in vertical tubes, inclined tubes, and vertical annuli.The data were obtained in gas-liquid systems which included combinations ofair, propane and natural gas (over 97 percent methane) with water, lubricatingoils, and crude oils. The 214 data points obtained in this study along with 11data points reported in the literature are incorporated in an empiricalcorrelation which relates the mean slip velocity of gases flowing throughliquids with the parameters gas rate, tube size, ratio of liquid viscosity toliquid density, gas density, liquid density, and the angle of the tube from thevertical. The average numerical deviation of the measured slip velocity data fromvalues obtained from the correlation is 9.2 per cent. The average algebraicdeviation between measured and predicted data is 0.31 per cent, an indicationthat the correlation is a satisfactory representation of the data. The correlation presented in this paper will be useful primarily in thedesign of subsurface gas-oil separation equipment for increasing the efficiencyof oil-well pumping installations, but may perhaps be extended to othersituations of gases rising through liquid columns. Introduction The production of oil by pumping is often complicated by the presence offree and dissolved gas in the oil at bottomhole conditions. This gas can bedrawn into the pump barrel and result in "vapor locking" the pump, thusreducing the efficiency of the pumping operation. Large amounts of free gas maybe excluded from the pump by the use of a gas-anchor, which is designed toallow the separation of free gas from the oil before it is drawn into the pump.The design of a suitable gas-anchor depends on a knowledge of the differencebetween the velocity of the free gas and that of the oil as the oil travelsdown toward the pump intake. This rate of gas rise through the oil is termed"slip velocity. T.P. 3394

No abstract