Abstract: A composition and method comprising a polycationic agent and a polyanionic agent for delivering a peptide or protein into a cell.

Abstract: Provided is a methylation-specific restriction endonuclease for a DNA duplex substrate, which endonuclease recognizes in a strand of the duplex a 2 to 6 nucleotide recognition sequence comprising a 5-methylcytosine, and cleaves each strand of the duplex at a fixed position outside the recognition sequence.

Abstract: A DNA polymerase mutant comprising a Taq DNA polymerase amino acid sequence with a mutation at one or more of the following selected amino acid positions: E189K, E230K, E507K, H28R, L30R, G38R, F73V, H75R, E76A, E76G, E76K, E90K, K206R, E315K, A348V, L351F, A439T, D452N, G504S, E507A, D551N, L552R, I553V, D578N, H676R, Q680R, D732G, E734G, E734K, F749V; wherein the polymerase mutant exhibits relative to wild-type DNA polymerase increased polymerase speed, increased affinity to DNA substrate and/or increased resistance to a DNA polymerase inhibitor; and wherein, when the mutation is E507K in combination with two or more further mutations or the mutation is Q680R in combination with four or more further mutations, at least one of the further mutations is at one of the selected amino acid positions; and when the mutation is I553V, this is not in combination with D551S.

Abstract: A method for producing from host cells a heterologous polypeptide or protein comprising at least one cysteine residue in a reduced state. The method cultured the host cells in a culture medium comprising a reducing agent; and recovered the heterologous polypeptide or protein comprising at least one cysteine residue in a reduced state from the host cells or from the culture medium, where the host cells comprise a nucleic acid encoding the heterologous protein or polypeptide, and where the reducing agent is capable of permeating the plasma membrane of the host cells.

Abstract: Provided is a methylation-specific restriction endonuclease for a DNA duplex substrate, which endonuclease recognizes in a strand of the duplex a 2 to 6 nucleotide recognition sequence comprising a 5-methylcytosine, and cleaves each strand of the duplex at a fixed position outside the recognition sequence.

Abstract: A composition having nucleic acid polymerase activity, which comprises an active nucleic acid polymerase and an excess amount of a non-functional mutant nucleic acid polymerase protein, wherein the non-functional mutant nucleic acid polymerase protein stabilizes the active nucleic acid polymerase against loss of polymerase activity.

Abstract: A process for purifying plasmid DNA from a nucleic acid containing sample comprising plasmid DNA and contaminants, which process comprises a step of contaminant removal, comprising: (a) treating the sample to form a nucleic acid solution having a concentration of monovalent cations; (b) contacting the nucleic acid solution with an ultrafiltration membrane having a molecular weight exclusion limit of at least 30 kDa under conditions in which substantially no gel-layer forms and in which the concentration of monovalent cations is sufficiently high for a time sufficient to remove substantially all RNA and form a retentate containing plasmid DNA; and (c) collecting the retentate.

Abstract: The invention relates to a method of preparing a gel for use in electrophoresis, which method comprises: (a) providing a mixture comprising a solvent, agarose or a derivative thereof, one or more vinyl monomers, and a polymerisation initiator, the initiator forming a redox system with agarose or the derivative thereof; (b) exposing the mixture to polymerisation conditions to graft-polymerise the one or more monomers onto the agarose or derivative thereof; and (c) allowing the mixture to form a gel.

Abstract: Use of a DNA polymerase enzyme as a single stranded RNA exoribonuclease.

Abstract: A vector for transformation into a host cell is described comprising a toxic gene encoding a product that is lethal to the host cell, wherein the toxic gene comprises: an essential sequence region whose integrity is necessary in order for the encoded toxic gene product to be lethal to the host cell; an inessential sequence region whose integrity is not essential in order for the encoded toxic gene product to be lethal to the host cell; a regulatory sequence inserted in-frame into the inessential sequence region; and a cloning site within the essential sequence region for insertion of a nucleic acid sequence, wherein the regulatory sequence and the cloning site are positioned so as to allow the regulatory sequence to be operably linked to a nucleic acid sequence when the nucleic acid sequence is inserted into the cloning site.

Abstract: A process for producing a polynucleotide encoding a restriction endonuclease with an altered specificity, which process comprises: (a) mutagenising a polynucleotide encoding a restriction endonuclease with specificity for a recognition sequence so as to produce one or more mutated polynucleotides; and (b) isolating therefrom a polynucleotide encoding a mutated restriction endonuclease with specificity for an altered recognition sequence by selecting a polynucleotide which expresses a restriction endonuclease with methylase specificity for the altered recognition sequence.