Abstract: A method for identifying an inhibitor of dehydroquinate synthase (DHQS) and/or dehydroquinase (DQ), which method comprises: i) contacting a test substance with DHQS and a substrate for DHQS and contacting the resulting reaction mixture with DQ, or contacting the test substance with DQ and a substrate for DQ; and ii) contacting the resulting reaction mixture with dehydroshikimate dehydratase (DHSD); and iii) determining whether the test substance inhibits the activity of DHQS or DQ.

Abstract: Attenuated microorganism for use in immunoprophylaxis in which the attenuation is brought about by the presence of a mutation in the DNA sequence of the microorganism which encodes, or which regulates the expression of DNA encoding a protein that is produced in response to environmental stress, the microorganism optionally being capable of expressing DNA encoding a heterologous antigen.

Abstract: A polypeptide for use in a vaccine against Bordetella pertussis, B. parapertussis or B. bronchiseptica contains an epitope selected from (a) the amino acid sequence coded for by nucleotides 1885 to 1902 of the P.69 gene of B. pertussis CN2992; (b) the corresponding amino acid sequence of another strain of B. pertussis or of a strain of B.parapertussis or B. bronchiseptica; and (c) a modified version of sequence (a) or (b) which has substantially the same antigenicity. The polypeptide is no more than 50 amino acid residues long or is a chimaeric protein composed of a carrier protein sequence and a sequence of no more than 50 amino acid residues which contains the required epitope.

Abstract: Attenuated microorganism for use in immunoprophylaxis in which the attenuation is brought about by the presence of a mutation in the DNA sequence of the microorganism which encodes, or which regulates the expression of DNA encoding a protein that is produced in response to environmental stress, the microorganism optionally being capable of expressing DNA encoding a heterologous antigen.

Abstract: The invention concerns a method of prophylactically treating a host against infection by a microorganism, which method comprises administering to the host an attenuated Salmonella bacterium which contains a nirB promoter operably linked to a DNA sequence encoding a heterologous protein. The heterologous protein is expressed in the host and induces in the host an immune response against the microorganism.