Diamidino-2-phenylindole dihydrochloride

An evanescent wave biosensor was devised for determination of analytes capable of intercalation in dsDNA in a FIA system. A polyethylene lensed optical fiber is coated with a thin polymeric layer containing dsDNA which is immobilized there. The fiber is placed in a FLA system immersed in a solution of ethidium bromide (144), which undergoes intercalation in the dsDNA. The fluorescence signal of 144 is thus enhanced about a 1000-fold relative to the evanescent wave fluorescence measurement without the coating and is dependent on the concentration in solution. If an analyte is present in the same solution, it competes with 144 for intercalation in the DNA and causes fluorescence quenching, which can be measured and correlated to the analyte concentration. This method was applied to determination of various analytes, including 4, 6-diamidino-2-phenylindole dihydrochloride (145)247. 

Leusch, H.G., Hoffman, M., and Emeis, C.C. 1985. Fluorometric determination of the total DNA content of different yeast species using 4 6-diamidino-2-phenylindole dihydrochloride. Can. J. Microbiol. 31,1164—1166. 

Chromosomal localization of the axl gene is done by fluorescence in situ hybridization (FISH). The biotin-labeled axl probe is from a cosmid vector containing a 41-kb genomic fragment. The slides with human metaphase cells for chromosomal DNA to be denatured are immersed into a solution of 70 % formamide-x4 in saline sodium citrate buffer (SSC) atpH 7.0 (0.15 M NaCl 0.015 M sodium citrate) at 70 °C for 2 min. For the slides, the hybridization mixture kept at 75 °C consists of 50 %formamide,xl SSC, 10 % dextran sulfate pH 7.0, and 150 mL unlabeled sonicated total human genomic DNA add 50-100 ng labeled probe. The mixture is incubated at 37 °C for 10 min. The slides are washed in 50 % formamide and SSC x3, 5 min each at 40 °C and in SSC x3 at 40 °C. The detection reagent consists of x4 SSC-0.1 % Triton, and 1 % bovine semm albumin for 3 washes 3 min each at 40 °C. The slides are incubated with fluorescein isothiocyanate-conjugated avidin at 37 °C for 30 min. Metaphase cells are counterstained with 4,6-diamidino-2-phenylindole dihydrochloride 200 ng/mL in 2x SSC for 5 min at... 

Inc. 1 2000) for 1 h at room temperature. The cells were washed with PBS and counterstained with DAPI (4, 6-diamidino-2-phenylindole dihydrochloride) to visualize the nuclear morphology. The immunoreactive images were acquired by a confocal laser scanning microscopy (LSM5 PASCAL, Carl Zeiss, lend, Germany). The dendritic morphology was analyzed with the aid of Neurocyte Image Analyzer Software (Kurabo, Osaka, Japan). 

Cell organelle specific fluorescent markers, e.g., MitoTracker or ER-Tracker Red or 4, 6-Diamidino-2-phenylindole dihydrochloride (DAPI) optional). See Note 6. 

Figure 2 Principle of spectral bio-imaging HUVEC incubated with pH-sensitive DOPE CHEMS liposomes (loaded with fluorescein isothiocyanate-dextran), cholera toxin subunit B (Alexa Fluor 594 labeled), and diamidino-phenylindole-dihydrochloride.

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