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Two novel approaches for the synthesis of fluorinated fluoresceins were developed through the use of fluorinated nitrobenzenes. The nitro group directed the fluoride displacement by methoxy groups at positions ortho and para establishing the resorcinol as the framework. Hydrodediazoniation and catalytic hydrogenation removed the directing nitro group, while demethylation yielded the desired fluorinated resorcinols.

The binding of a fluorescent diltiazem analogue (3R,4S)-cis-1- 2- 3- 3- 4,4-difluoro-3a,4-dihydro-5,7-dimethyl-4-bora-3a,4 a-diaza-s-indacen-3-yl propionyl amino ethyl -1,3,4,5-tetrahydro-3-hydroxy-4 -(4-methoxyphenyl)-6-(trifluoromethyl)-2H-1-benzazepin-2-one to L-type Ca2+ channels in the presence of 1,4-dihydropyridines has been investigated. The results showed that the binding domains of these drugs are localized in close proximity to each other on the extracellular side of the channel.

Newly developed N-propylamino-substituted benzazepinones (NPSBs) enable the study of the benzothiazepinone (BTZ) binding domain of muscle L-type calcium channels (LTCCs). Drug binding causes the occurrence of fluorescence resonance energy transfer between tryptophan residues of the channel protein and the NPSB derivatives. The kinetic properties of these derivatives confirm the existence of a high-affinity BTZ binding domain on purified LTCCs.

Examination of the binding-stimulated fluorescence properties of a fluorescent 1,4-dihydropyridine (DHP) and its analogue DMBODIPY-DHP helps investigate the molecular mechanism of the interaction of DHPs with alpha1-subunit of skeletal muscle L-type Ca2+-channels. Fluorescence yield of DMBODIPY-DHP decreases to specific binding. Binding permits the fluorescence resonance energy transfer (FRET) from between ligand and tryptophan residues to the alpha1-subunit. FRET signal helps direct measurements of DHP binding of high resolution. Application of this technique reveals a step-wise mechanism associated with reversible DHP binding to L-type Ca2+ channels.

The application of quantitative real-time PCR (qPCR) technologies for the rapid identification of fecal bacteria in environmental waters is being considered for use as a national water quality metric in the United States. The transition from research tool to a standardized protocol requires information on the reproducibility and sources of variation associated with qPCR methodology across laboratories. This study examines interlaboratory variability in the measurement of enterococci and Bacteroidales concentrations from standardized, spiked, and environmental sources of DNA using the Entero1a and GenBac3 qPCR methods, respectively. Comparisons are based on data generated from eight different research facilities. Special attention was placed on the influence of the DNA isolation step and effect of simplex and multiplex amplification approaches on interlaboratory variability. Results suggest that a crude lysate is sufficient for DNA isolation unless environmental samples contain substances that can inhibit qPCR amplification. No appreciable difference was observed between simplex and multiplex amplification approaches. Overall, interlaboratory variability levels remained low (<10% coefficient of variation) regardless of qPCR protocol.