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W Heiser

Publications and source records attributed to W Heiser.

17 recordsLinked to original sources

Fast gel electrophoresis to analyze DNA-protein interactions.

A rapid method for electrophoresis of DNA-protein complexes is described. Popular "gel-shift" assays are performed using Pharmacia PhastSystem with its convenience of pre-cast gels and buffer strips and microprocessor-controlled high-resolution separation. Using this system, the products of a DNA binding reaction (DNA-protein complexes) can be separated from "free" DNA in less than one hour. DNA fragments as well as oligonucleotides have been used as targets with partially purified extracts containing sequence-specific DNA binding proteins. We present here a comparison of results of gel-shift assays obtained by conventional techniques and by our rapid "PhastShift" method which reduces the time, effort and technical expertise necessary to obtain reproducible results.

Antigens, Viral

[Paraocclusal spoon].

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Dental Impression Technique

[Case report].

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Activator Appliances

Inhibition of the growth of mammalian cells in cuture by amino acids and the isolation and characterization of L-phenylalanine transport.

Raising the concentration of phenylalanine and other amino acids in MEM leads to the inhibition of growth and in some cases to death of A9. Balb 3T3 , SV40 Balb 3T3 (SVT2), CHO, and WI38. All cells tested exhibited some similar senstivities to certain of the amino acids. but there were some unique differences. Phenylalanine-resistant mutants (Pher) of A9 were isolated that had modified phenylalanine-transport properties. These mutants can be isolated by a single-step selection procedure. A Lineweaver-Burk plot of initial rates of phenylalanine uptake by A9 and mutants showed a biphasic curve suggesting two transport systems. The Pher mutants had altered properties of both systems. It is suggested that the selection of clones resistant to high concentration of several of the natural amino acid may be used as a general method for the isolation of mutants affecting the various amino acid transport systems in mammalian cells.

Amino Acids, Essential