Publications by authors named "Priscilla Stevens"

Depression is a major global health concern expected to worsen by 2030. In 2019, 28 million individuals were affected by depressive disorders. Dietary and supplemental vitamins show overall favorable preventative and therapeutic effects on depression.

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Here we report proof-of-principle for a microsphere-based genotyping assay that detects single nucleotide polymorphisms (SNPs) directly from human genomic DNA samples. This assay is based on a structure-specific cleavage reaction that achieves single base discrimination with a 5'-nuclease which recognizes a tripartite substrate formed upon hybridization of target DNA with probe and upstream oligonucleotides. The assay is simple with two easy steps: a cleavage reaction, which generates fluorescent signal on microsphere surfaces, followed by flow cytometry analysis of the microspheres.

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An automated imaging system was developed to quantify fluorescence signals from particles immobilized on hydrogel-coated slides. Arrays of submicrometer-diameter particles were printed with up to 600 particles/spot. The slides were read under 20x magnification without cover slips.

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Combining positive attributes of planar arrays and suspension arrays, immobilized particle arrays offer a new format in which immobilized submicrometer particles are arrayed on hydrogel-coated slides, providing 100+ assay replicates within each spot. This research describes how to prepare immobilized protein arrays and how to assay the binding of labeled target molecules to the arrayed capture probes. The assay system exhibits an intrinsic dynamic range of two to three decades, with coefficients of variation from 5 to 10%.

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The structure-specific invasive cleavage reaction is a useful means for sensitive and specific detection of single nucleotide polymorphisms, or SNPs, directly from genomic DNA without a need for prior target amplification. A new approach integrating this invasive cleavage assay and surface DNA array technology has been developed for potentially large-scale SNP scoring in a parallel format. Two surface invasive cleavage reaction strategies were designed and implemented for a model SNP system in codon 158 of the human ApoE gene.

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The structure-specific invasive cleavage of single-stranded DNA by 5' nucleases is a useful means for sensitive detection of single-nucleotide polymorphisms or SNPs. The solution-phase invasive cleavage reaction has sufficient sensitivity for direct detection of as few as 600 target molecules with no prior target amplification. One approach to the parallelization of SNP analysis is to adapt the invasive cleavage reaction to an addressed array format.

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