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Computer software that allows the simulation of any chromatographic separation as a function of simultaneous changes in any one or two variables that can affect sample separation order (selectivity) is described. For one example, an application is described for the simultaneous variation of the mobile phase pH and gradient time in reversed-phase liquid(More)
The high-performance liquid chromatographic separation of a large variety of nucleic acid constituents on a silica-based, weak-anion exchange column was accomplished. Using this technique it was possible to achieve some relatively difficult separations, such as the separation of 2'-, 3'-, and 5'-AMP, and the separation of a mixture of ribo- and(More)
A single column reverse phase high pressure liquid chromatographic method is described for the determination of vitamins D2 and D3 in fluid milk. Resolution of vitamin D2 from D3 is helpful for use as an internal standard. The method involves overnight saponification at room temperature, extraction of unsaponifiables, precipitation of cholesterol, and(More)
We have screened about 1.4 million colonies of Escherichia coli K-12 for their ability to grow on nutrient agar at 30 degrees and 41 degrees. Among the 2266 temperature-sensitive mutants found, 110 were defective in DNA synthesis but not in protein synthesis at 41 degrees. Three of these dna mutations mapped at two previously undescribed loci on the E. coli(More)
Synthesis of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein was determined in Saccharomyces cerevisiae during amino acid and pyrimidine starvation and during shift-up and shift-down conditions. During amino acid starvation, cell mass, cell number, and RNA continued to increase for varying periods. During amino acid and pyrimidine(More)
Four cold-sensitive mutants of Escherichia coli have been isolated which show a reduced ability to synthesize deoxyribonucleic acid at low temperature. The mutants also have a reduced ability to incorporate nucleoside triphosphates into deoxyribonucleic acid at low temperature in cell preparations made permeable with toluene. All four mutations are located(More)
Biopolymer separations were studied on Micropak TSK type SW columns, which contain an aqueous compatible steric exclusion support. Columns of two different pore sizes, designated 2000SW and 3000SW, were compared for separation of proteins and nucleic acids covering a molecular weight range of 13,500 to 340,000 and the effect of molecular shape and(More)
Reversed-phase microbore high-performance liquid chromatography was investigated for high-sensitivity analysis of phenylthiohydantoin (PTH) amino acids. A mixed nitrile alkylsilane bonded phase was developed and ternary gradient elution conditions were devised for resolution of the common PTH amino acids. Elution conditions were developed with a(More)