Herein reported are new tricyclic cytidine compounds, such as 8-diethylamino-tC (8-DEA-tC), that respond to DNA and/or RNA duplex formation with up to a 20-fold increase in fluorescent quantum yield as compared with the free nucleoside, depending on neighboring bases. This turn-on response to duplex formation is by far the greatest of any reported nucleoside analogue that can participate in Watson-Crick base pairing. Measurements of the quantum yield of 8-DEA-tC mispaired with adenosine and, separately, opposite an abasic site show that there is almost no fluorescence increase without the formation of correct Watson-Crick hydrogen bonds. Kinetic isotope effects from the use of deuterated buffer show that the duplex protects 8-DEA-tC against quenching by excited state proton transfer. DFT calculations provide a rationale for the observed photophysical properties that is dependent on duplex integrity and the electronic structure of the analogue.

Herein reported are new tricyclic cytidine compounds, such as 8-diethylamino-tC (8-DEA-tC), that respond to DNA and/or RNA duplex formation with up to a 20-fold increase in fluorescent quantum yield as compared with the free nucleoside, depending on neighboring bases. This turn-on response to duplex formation is by far the greatest of any reported nucleoside analogue that can participate in Watson-Crick base pairing. Measurements of the quantum yield of 8-DEA-tC mispaired with adenosine and, separately, opposite an abasic site show that there is almost no fluorescence increase without the formation of correct Watson-Crick hydrogen bonds. Kinetic isotope effects from the use of deuterated buffer show that the duplex protects 8-DEA-tC against quenching by excited state proton transfer. DFT calculations provide a rationale for the observed photophysical properties that is dependent on duplex integrity and the electronic structure of the analogue.

Methods are provided for nucleic acid analysis wherein a target nucleic acid that is at least partially double stranded is mixed with a dsDNA binding dye having a percent saturation of at least 50% to form a mixture. In one embodiment, the nucleic acid is amplified in the presence of the dsDNA binding dye, and in another embodiment a melting curve is generated for the target nucleic acid by measuring fluorescence from the dsDNA binding dye as the mixture is heated. Dyes for use in nucleic acid analysis and methods for making dyes are also provided.

Methods are provided for nucleic acid analysis wherein a target nucleic acid that is at least partially double stranded is mixed with a dsDNA binding dye having a percent saturation of at least 50% to form a mixture. In one embodiment, the nucleic acid is amplified in the presence of the dsDNA binding dye, and in another embodiment a melting curve is generated for the target nucleic acid by measuring fluorescence from the dsDNA binding dye as the mixture is heated. Dyes for use in nucleic acid analysis and methods for making dyes are also provided.

The present teachings generally relate to methods and kits incorporating a discriminating positive control for determining whether a particular microorganism or group of microorganisms are present in a sample, for example but not limited to a food, environmental, agricultural, biopharmaceutical, pharmaceutical, or water sample. According to certain methods, at least part of a starting material, for example but not limited to, a food, environmental, agricultural, biopharmaceutical, pharmaceutical, or water sample can be combined with a culture medium and incubated under conditions suitable for microbial growth followed by extracting microorganism and added control nucleic acids for analysis. The extracted nucleic acids are amplified and the amplified nucleic acids are detected, directly or indirectly, and the fidelity of the methods and the presence or absence of the corresponding microorganism is determined because the discriminating positive control provides both confirmatory results for the methods used but eliminates false positive results.

The present teachings generally relate to methods and kits incorporating a discriminating positive control for determining whether a particular microorganism or group of microorganisms are present in a sample, for example but not limited to a food, environmental, agricultural, biopharmaceutical, pharmaceutical, or water sample. According to certain methods, at least part of a starting material, for example but not limited to, a food, environmental, agricultural, biopharmaceutical, pharmaceutical, or water sample can be combined with a culture medium and incubated under conditions suitable for microbial growth followed by extracting microorganism and added control nucleic acids for analysis. The extracted nucleic acids are amplified and the amplified nucleic acids are detected, directly or indirectly, and the fidelity of the methods and the presence or absence of the corresponding microorganism is determined because the discriminating positive control provides both confirmatory results for the methods used but eliminates false positive results.

The present disclosure provides methods for preparing a target mutant nucleic acid for subsequent enrichment relative to a wild type nucleic acid using nucleases that have a substantially higher activity on double stranded DNA versus single stranded DNA or RNA. The present disclosure also includes methods for enriching a target mutant nucleic acid and for preparing unmethylated/methylated nucleic acids of interest for subsequent enrichment.

The present disclosure provides methods for preparing a target mutant nucleic acid for subsequent enrichment relative to a wild type nucleic acid using nucleases that have a substantially higher activity on double stranded DNA versus single stranded DNA or RNA. The present disclosure also includes methods for enriching a target mutant nucleic acid and for preparing unmethylated/methylated nucleic acids of interest for subsequent enrichment.

Methods for designing and producing a fluorescent-labeled detection probe and a competitive probe combination are provided to improve detection by reducing noise. A method for designing the fluorescent-labeled detection probe and a competitive probe combination includes, for example, determining the base length and the base sequence of each of the fluorescent-labeled detection probe and the competitive probe. The determining can include experimentally determining the amount to be added to the nucleic acid sample of each of the fluorescent-labeled detection probe and the competitive probe. The methods provide a functional result of a first order derivative curve for the control target reaction sample having a substantial peak (maximum value), but a first order derivative curve for the control non-target reaction sample not having a substantial peak, the functional result improving detection by reducing noise.

Methods for designing and producing a fluorescent-labeled detection probe and a competitive probe combination are provided to improve detection by reducing noise. A method for designing the fluorescent-labeled detection probe and a competitive probe combination includes, for example, determining the base length and the base sequence of each of the fluorescent-labeled detection probe and the competitive probe. The determining can include experimentally determining the amount to be added to the nucleic acid sample of each of the fluorescent-labeled detection probe and the competitive probe. The methods provide a functional result of a first order derivative curve for the control target reaction sample having a substantial peak (maximum value), but a first order derivative curve for the control non-target reaction sample not having a substantial peak, the functional result improving detection by reducing noise.