Abstract: A method for analyzing a sample oligonucleotide sequence is described. The method comprises contacting the sample oligonucleotide sequence with an anchor sequence which comprises an immobilized oligonucleotide sequence which hybridizes with the sample. The sample is also contacted with a probe comprising an oligonucleotide sequence which hybridizes to a target oligonucleotide sequence to be detected in a suitable buffer to form a complex. The complex is subjected to a field which moves unbound oligonucleotide sequences away from the anchor sequence in the direction of the field, and preferably, extends the sample sequence. Whether the probe is bound to the sample oligonucleotide sequence, and preferably, the position of the probe, is determined to determine whether the target oligonucleotide sequence is present in the sample. The method can be used for mapping, for identity typing, and to determine whether a test oligonucleotide sequence is present in the sample.

Abstract: A process for bacterially producing heterologous polypeptides, particularly those such as human IFN-.beta. that inhibit bacterial growth, in which bacteria that have been transformed to express the heterologous polypeptide under the control of a trp promoter-operator are cultivated in a known volume of medium containing an excess of a preferred carbon source such as glucose and a predetermined amount of tryptophan that corresponds approximately to the amount of tryptophan contained in the bacteria in the volume of medium at a predetermined elevated cellular density, whereby expression of the heterologous polypeptide is substantially repressed until the bacteria grow to approximately the predetermined elevated cellular density and is thereafter automatically derepressed to permit expression of the heterologous polypeptide.

Abstract: A process for recovering IFN-.beta. from transformed bacteria comprising: disrupting the cell membranes of the bacteria; solubilizing the IFN-.beta. from the disruptate into an aqueous medium with a solubilizing agent such as sodium dodecyl sulfate; extracting the IFN-.beta. from the aqueous medium with 2-butanol, 2-methyl-butanol, or mixtures thereof under conditions that maintain phase separation between the aqueous meduim and the extractant; and isolating the IFN-.beta. from the extractant such as by precipitating the IFN-.beta. from an aqeous buffer mixture of the extractant by lowering the pH thereof.