Abstract: Two bacterial strains deficient in endogenous adenylate cyclase activity are provided. The strains, designated BTH101 and DHM1, are useful in a signal amplification system comprising a bacterial multi-hybrid system, and more preferably a two-hybrid system, of at least two chimeric polypeptides containing a first chimeric polypeptide corresponding to a first fragment of an enzyme and a second chimeric polypeptide corresponding to a second fragment of an enzyme or a modulating substance capable of activating said enzyme as described in published PCT application WO 99/28746. The signal amplification system is useful in a method of selecting a molecule of interest, which is capable of binding to target ligand, wherein the interaction between the molecule of interest and the target ligand is detected with the signal amplification system, and the kit therefor, as described in WO 99/28746.

Abstract: Fragments of nucleic acids derived from an appropriate mycobacteria genome, particularly Mycobacterium tuberculosis, their applications in the diagnosis of mycobacteria infections, as well as plasmides containing said fragments. The nucleotidic sequence is comprised of a nucleotidic sequence repeated in the genome of a mycobacterium and specific of the bacillus of tuberculosis and is characterized by a strong hybridation with M. tuberculosis.