Abstract: A composition comprising colloidal Fe3O4 particles coated with streptavidin is disclosed. These particles can be used in a method for separating biotinylated compounds from a solution in which the biotinylated compounds bind to the streptavidin-coated particles which are attracted to a surface by a magnet. Also disclosed is a method for making said streptavidin-coated composition, said method comprising the steps of forming colloidal Fe3O4 particles by mixing aqueous FeCl2 with aqueous FeCl3, adding aliquots of the mixture to an alkaline solution and adding streptavidin.

Abstract: A composition comprising colloidal Fe3O4 particles coated with streptavidin is disclosed. These particles can be used in a method for separating biotinylated compounds from a solution in which the biotinylated compounds bind to the streptavidin-coated particles which are attracted to a surface by a magnet. Also disclosed is a method for making said streptavidin-coated composition, said method comprising the steps of forming colloidal Fe3O4 particles by mixing aqueous FeCl2 with aqueous FeCl3, adding aliquots of the mixture to an alkaline solution and adding streptavidin.

Abstract: A method of analysing a nucleic acid is disclosed which involves the use of a mixture of labelled oligonucleotides in solution and an array of immobilized oligonucleotides. The target nucleic acid is incubated with the mixture of labelled oligonucleotides. Those labelled oligonucleotides which hybridize are recovered and incubated with the array of immobilized oligonucleotides. Sequence information is obtained by observing the location of the label on the array. The method is particularly suitable for determining differences between nucleic acids.

Abstract: A method for primer walking cycle sequencing of nucleic acid is provided using a presynthesized set of walking primers wherein the primers have a raised annealing temperature and/or improved annealing properties.

Abstract: A method determining the number of repeats in a tandem repeat sequence of a nucleic acid target comprises providing an array of nucleic acid probes immobilized at spaced locations on a surface of a support. Each probe of the array has a tandem repeat sequence complementary to that in the target and containing a different number of repeats. When the target is hybridized with the array and forms a perfect match with the probe having the same number of repeats in the tandem repeat sequence, it is not removed by exonuclease treatment and can be detected on the array.

Abstract: A method for primer walking cycle sequencing of nucleic acid is provided using a presynthesized set of walking primers wherein the primers have a raised annealing temperature and/or improved annealing properties without increasing sequence complexity.

Abstract: Biological assay systems often involve suspending magnetically attractable particles in a liquid, and later bringing down the particles from suspension and separating the formed pellet from the supernatant liquid. The invention provides magnetic systems for this purpose, shaped to form an annular or part-annular pellet close to the bottom of the vessel. The systems are suitable for automation.

Abstract: Biological assay systems often involve suspending magnetically attractable particles in a liquid, and later bringing down the particles from suspension and separating the formed pellet from the supernatant liquid. The invention provides magnetic systems for this purpose, shaped to form an annular or part-annular pellet close to the bottom of the vessel. The systems are suitable for automation.

Abstract: A method of sequencing a target nucleic acid using primer extension mass spectroscopy to generate an observed mass spectrum, on which base calling cycles are carried out using calibrated inter-peak mass difference values such that: each called base allows mass calculation for the base-called peak in the observed mass spectrum; this calculated mass is then used as a further calibration point for subsequent rounds of base calling. A reaction mixture of all four base-specific chain extension nucleotides and four chain termination nucleotide analogues. A method of performing mass spectroscopy, which method comprises subjecting molecular ions which have been chemically charged in a predetermined manner to time-of-flight or Fourier transform mass spectroscopy.

Abstract: A method of recovering a biopolymer from solution involves the use of magnetically attractable beads which do not specifically bind the polymer. The beads are suspended in the solution. Then the polymer is precipitated out of solution and becomes non-specifically associated with the beads. When the beads are magnetically drawn down, the polymer is drawn down with them. The polymer can subsequently be resolubilized and separated from the beads.

Abstract: Fluorescently labelled dideoxynucleoside triphosphates are widely used as chain-terminators in Sanger dideoxy sequencing operations. But these unincorporated dye-terminators migrate in an electrophoresis gel and obscure the desired sequence ladder. This invention provides a method and a kit for modifying the unincorporated dye-terminators, e.g. by removal of a 5'-triphosphate group by chemical or enzymatic means e.g. by use of a phosphatase enzyme.

Abstract: A method of recovering a first material, e.g. plasmid DNA, from a solution containing pre-precipitated second material, e.g. genomic DNA and cellular debris, by precipitating the first material in the presence of magnetically attractable beads which become non-specifically associated with the newly formed precipitate, using a magnet to draw down the beads and the newly formed precipitate, and removing the supernatant.