An isolated polynucleotide encoding a modified luciferase polypeptide and substrates. The OgLuc variant polypeptide has at least 60% amino acid sequence identity to SEQ ID NO: 1 and at least one amino acid substitution at a position corresponding to an amino acid in SEQ ID NO: 1. The OgLuc variant polypeptide has at least one of enhanced luminescence, enhanced signal stability, and enhanced protein stability relative to the corresponding polypeptide of the wild-type Oplophorus luciferase.

An isolated polynucleotide encoding a modified luciferase polypeptide and substrates. The OgLuc variant polypeptide has at least 60% amino acid sequence identity to SEQ ID NO: 1 and at least one amino acid substitution at a position corresponding to an amino acid in SEQ ID NO: 1. The OgLuc variant polypeptide has at least one of enhanced luminescence, enhanced signal stability, and enhanced protein stability relative to the corresponding polypeptide of the wild-type Oplophorus luciferase.

The screening method of the present invention is useful for screening drugs such as insulin secretagogues having an insulin secretagogue activity with minimized side effects (hypoglycemia induction, etc.). The transformant in which a polynucleotide encoding the fusion protein used for the screening method is introduced, the screening kit comprising the transformant, etc. are also useful for screening excellent drugs.

The screening method of the present invention is useful for screening drugs such as insulin secretagogues having an insulin secretagogue activity with minimized side effects (hypoglycemia induction, etc.). The transformant in which a polynucleotide encoding the fusion protein used for the screening method is introduced, the screening kit comprising the transformant, etc. are also useful for screening excellent drugs.

A method for monitoring microbial levels in a wellbore fluid is provided. The method includes collecting a wellbore fluid sample, recovering ATP from the wellbore fluid sample, using the recovered ATP in an ATP-mediated oxidation of luciferin to oxyluciferin to yield photons, quantifying the photons, correlating the quantified photons to an ATP concentration, comparing the ATP concentration to predetermined action levels, and taking countermeasures when the ATP concentration exceeds the predetermined action levels.

A method for monitoring microbial levels in a wellbore fluid is provided. The method includes collecting a wellbore fluid sample, recovering ATP from the wellbore fluid sample, using the recovered ATP in an ATP-mediated oxidation of luciferin to oxyluciferin to yield photons, quantifying the photons, correlating the quantified photons to an ATP concentration, comparing the ATP concentration to predetermined action levels, and taking countermeasures when the ATP concentration exceeds the predetermined action levels.

Methods of detecting target bacteria are provided. In some embodiments the methods comprise exposing the sample to a phage capable of infecting a set of target bacteria and comprising a heterologous nucleic acid sequence encoding a marker. In some embodiments the target bacteria comprise Listeria. In some embodiments the target bacteria are all Listeria. Recombinant Listeria phage comprising a heterologous nucleic acid sequence encoding a marker are also provided as are useful combinations of such phage and articles of manufacture comprising such phage, among other things.

Methods of detecting target bacteria are provided. In some embodiments the methods comprise exposing the sample to a phage capable of infecting a set of target bacteria and comprising a heterologous nucleic acid sequence encoding a marker. In some embodiments the target bacteria comprise Listeria. In some embodiments the target bacteria are all Listeria. Recombinant Listeria phage comprising a heterologous nucleic acid sequence encoding a marker are also provided as are useful combinations of such phage and articles of manufacture comprising such phage, among other things.

A method for detecting the presence of bacterial spores is described by measuring microbial metabolic activity over time. Spores are distinguished from vegetative cells and other microorganisms by detecting a burst of metabolic activity indicating germination of spores. This method may be used to detect bacterial spores in a commercial process system, such as a papermaking system within the time frame of a typical work shift.

A method for detecting the presence of bacterial spores is described by measuring microbial metabolic activity over time. Spores are distinguished from vegetative cells and other microorganisms by detecting a burst of metabolic activity indicating germination of spores. This method may be used to detect bacterial spores in a commercial process system, such as a papermaking system within the time frame of a typical work shift.