Abstract: Additives are proposed for compositions comprising radiolabelled organic compounds e.g. 32P-labelled nucleotides. Stabilizers are selected from tryptophan, para-aminobenzoate, indoleacetate and the azole group. Dyes are selected from Sulphorhodamine B, Xylene Cyanol, Azocarmine B and New Coccine. Preferred compositions contain both stabilizer and dye.

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: Additives are proposed for compositions comprising radiolabelled organic compounds e.g. 32P-labelled nucleotides. Stabilizers are selected from tryptophan, para-aminobenzoate, indoleacetate and the azole group. Dyes are selected from Sulphorhodamine B, Xylene Cyanol, Azocarmine B and New Coccine. Preferred compositions contain both stabilizer and dye.

Abstract: Apparatus and method for studying cellular processes comprise a vessel having a base including a layer comprising a scintillant substance and which is adapted for attachment and/or growth of cells. Cellular processes are examined by scintillation proximity assay using a reagent labelled with a radioisotope.

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.

Abstract: A method of producing an RNA fingerprint of a poly(A).sup.+ RNA preparation. At least one oligonucleotide primer and a supply of nucleotides of which one is a terminator nucleotide, are added to the poly(A).sup.+ RNA preparation or a single-stranded cDNA preparation derived from it. cDNA products are synthesized from the RNA, or DNA products from the cDNA and the products are separated to produce an RNA fingerprint.

Abstract: Novel compounds obtainable by reacting together an imido-reagent such as diphenylphosphonimido-triphenylphosphorane), or a phosphine oxide such as p-tolyldiphenylphosphine oxide, with a chelate of a transition or lanthanide or actinide metal, such as tris(dibenzoylmethide)europium III, have the property of fluorescing in UV radiation. The invention includes solid polymer bodies containing such compounds, or chelates of transition or lanthanide or actinide metals generally, the bodies having the property of emitting light or infra-red radiation when subjected to a flux of ultra-violet or ionising radiation by virtue of internally generated, e.g. by tritium ionising radiation. The body is preferably of polystyrene formed by polymerising the monomer in the presence of the compound or metal chelate.

Abstract: A novel process is disclosed utilizing a subtraction hybridization technique for producing DNA hybridization probes of high specific activity or cDNA subtraction libraries, useful in connection with the cloning of differentially expressed genes. A preparation of single stranded cDNA derived from transcript mRNA of a target cell source is subjected to subtraction hybridization using excess single stranded "driver" nucleic acid from a reference cell source so that all the cDNA having a nucleotide sequence complementary to transcript mRNA of the reference cell source is subtracted by annealing with the "driver" nucleic acid to form duplex molecules.

Abstract: Novel complexes of technetium (.sup.99 Tc or .sup.99m Tc) which contain the moiety Tc.dbd.NR, Tc--N.dbd.NY or Tc(--N.dbd.NY).sub.2, and a ligand which confers biological target-seeking properties on the complex, wherein R represents an aryl group, a substituted or unsubstituted alkyl group, or the grouping .dbd.NR.sup.1 R.sup.2 ; Y represents an aryl group or a substituted or unsubstituted alkyl group; and R.sup.1 and R.sup.2 are hydrogen, aryl groups or substituted or unsubstituted aliphatic or cyclic alkyl groups, and may be both the same or different, provided that both are not hydrogen. The complexes are suitable for use in radiopharmaceuticals for a variety of clinical applications. Methods for the preparation of these technetium complexes are also described.

Abstract: A novel process is disclosed utilizing a subtraction hybridization technique for producing DNA hybridization probes of high specific activity or cDNA subtraction libraries, useful in connection with the cloning of differentially expressed genes. A preparation of single stranded cDNA derived from transcript mRNA of a target cell source is subjected to subtraction hybridization using excess single stranded "driver" nucleic acid from a reference cell source so that all the cDNA having a nucleotide sequence complementary to transcript mRNA of the reference cell source is subtracted by annealing with the "driver" nucleic acid to form duplex molecules.

Abstract: Phosphoramidite derivatives of formula (V), ##STR1## wherein X is biotin and Y is a protecting group. There may be a linker arm, of variable length, between X and the rest of the molecule. Examples of the protecting group Y include 4,4'-dimethoxytrityl, trifluoroacetyl and fluorenylmethoxycarbonyl (Fmoc). The phosphoramidite derivatives are useful in single or multiple labelling of synthetic oligonucleotides. Process for the preparation of these phosphoramidite derivatives are also disclosed.

Abstract: A device for capturing a component present in a fluid 18 a pipette tip having a rearward end 15 adapted to be fitted on a micro-pipette, and a forward end 12 with a membrane 17, adapted to bind the component, extending across the pipette tip.

Abstract: An automatic device has a pipette (46) which is movable by motors along a guided path (48) between first and second locations at which a supply and storage vial (43) and a rack (45) for carrying one or more receptacle tubes (44) are respectively positioned. The motors operate also to lower the tip of the pipette (46) into positions to aspirate liquid from the storage vial (43) and to expel the aspirated liquid into one of the receptacle tubes (44), and the pipette has associated with it an automatically operating device for drawing liquid into and expelling liquid from the pipette tip. In an alternative construction, a single location is provided in which either a supply vial or a dispensing container can be positioned. In automatic operation, all of the liquid in the vial is drawn into the pipette and is subsequently discharged in required quantitites into dispensing containers placed successively in said locations.

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: Hybridization buffers, for hybridizing complementary polynucleotides, contain polyvinyl alcohol (MW 1000-20000) and/or polystyrene sulphonic acid (e.g. MW 60000-80000) as a rate enhancer, generally at a concentration of 1-10%. Dextran sulphate, polyethylene glycol and cationic detergents may be additionally present. The method is useful when one of the two complementary polynucleotides is immobilised, or is in in situ hybridizations.

Abstract: Agents for the diagnosis or treatment of hypoxic cells comprise a bioreductive moiety such as 2-nitroimidazole, and a metal chelating moiety which is a bis-amine oxime of which a carbon atom adjacent a nitrogen atom is linked to the bioreductive moiety. A chelated metal atom or ion preferably Technetium-99m. The agent diffuses into cells where the 2-nitroimidazole is reduced thus trapping the chelated metal in the cell.

Abstract: A method of testing for target bacteria involves adding bacteriophage to a sample to infect the bacteria in the sample; killing extracellular bacteriophage without at the same time killing phage-infected bacteria; amplifying bacteriophage remaining in the sample; and causing the bacteriophage to infect reporter bacteria and thereby produce an observable signal. The reporter bacteria are genetically engineered to have an indicator gene which on expression gives rise to a detectable signal, wherein expression of the indicator gene is initiated on bacteriophage infection of the bacteria.

Abstract: Additives are proposed for compositions comprising radiolabelled organic compounds e.g. 32P-labelled nucleotides. Stabilisers are selected from tryptophan, para-aminobenzoate, indoleacetate and the azole group. Dyes are selected from Sulphorhodamine B, Xylene Cyanol, Azocarmine B and New Coccine. Preferred compositions contain both stabiliser and dye.

Abstract: An apparatus includes an enclosed chamber in which a motor-driven cylinder is mounted for rotation about a horizontal axis. The lower half of the cylinder is disposed in a trough. A blot can be attached, analyte side outward, to the surface of the cylinder, and the cylinder is then rotated to carry the blot through a succession of treatment liquids, with which the trough is charged. Each liquid is discharged from the through before the next liquid is supplied. The liquid in the through can be maintained at any desired temperature above the ambient temperature. Water can be sprayed onto the blot to wash a liquid off and to flush the trough. The blot may be held in position on the cylinder by rollers which engage only the side edges of the blot.