Abstract: The present invention provides methods and kits for detection, and optionally quantitation, of multiple nucleic acid sequence analytes in a single fluid sample. The assays and kits of the invention employ a plurality of species of capture probes, each species comprising a bacteriophage covalently or non-covalently linked to an oligonucleotide complementary to one analyte, wherein the bacteriophage of each species is capable of generating a distinctive signal when plated on an indicator medium. The oligonucleotide moieties of each capture probe contain a sufficient number of contiguous ribonucleotides to confer sensitivity to a ribonuclease specific for RNA/DNA or RNA/RNA duplexes. In the method of the invention, the capture probe species are combined with the fluid sample, which has been processed to release single-stranded nucleic acids. Hybridization is allowed to occur, thereby generating DNA/RNA or RNA/RNA duplexes.

Abstract: The present invention provided compositions, methods and kits for detection and quantitation of pathogenic organisms. The composition of the invention is an oligonucleotide probe comprising a bacteriophage covalently linked to one site on an oligonucleotide probe complementary to a conserved region of a pathogenic organism. At a second site, the oligonucleotide probe is linked to a matrix. The oligonucleotide probe contains a region complementary to one strand of a restriciton endonuclease recognition site or an oligoribonucleotide moiety. The number of pathogenic organisms present in a biological fluid sample may be quantitated in accordance with the method of the invention by combining the composition of the invention with the sample, allowing hybridization to occur. Hybridization generates a DNA-RNA hybrid, and by adding the appropriate nucleolytic enzyme capable of cleaving DNA-RNA hybrids; bacteriophage will be released for measurement.

Abstract: Disclosed is a protein construct including a chemically modified lambdoid tail protein having a chemically reactive amino acid residue linked to a target molecule. Also disclosed is an infective lambdoid bacteriophage displaying on its outer surface the chemically modified tail protein. In addition, methods of detecting a molecule-of-interest in a solution and methods of detecting cells producing a molecule-of-interest which utilize the infective lambdoid bacteriophage having the chemically modified tail protein are disclosed.

Abstract: Disclosed is an infective lambdoid bacteriophage which includes a protein construct comprising a genetically modified major tail protein truncated at its carboxy terminus, and a target molecule peptide bonded to the carboxy terminus of the tail protein. Also disclosed are nucleic acids encoding the construct and methods of detecting a molecule-of-interest in a solution and of detecting a cell which produces a molecule-of-interest.

Abstract: Disclosed is a method for isolating a mutant cell that excretes a desired compound. The method includes culturing a plurality of auxotrophic pretreated starter cells and auxotrophic feeder cells in the presence of a reversibly noninfective, modified lambdoid bacteriophage. If the treated starter cell produces the desired compound, the bacteriophage will be rendered infective and infect the feeder cell. The feeder cell, in turn, will excrete a metabolite required by the starter cell and the starter cell will excrete a metabolite required by the feeder cell, enabling the cells to cross-feed, grow, and produce a colony containing a starter cell which produces the desired compound.