The Hoechst dye fluorescence technique, which is used for the quantitative determination of DNA (12), requires high saline concentrations at neutral pH to reach maximal fluorescence of the DNA-dye complex and to render the DNA fully accessible to the dye by dissociating foreign molecules (3,12). In conventional assays, the DNA is alcohol-precipitated and then resuspended in buffer containing 2 ...

• Acridine orange (A-1301, A-3568; Section 8.1) is one of the most popular and versatile fluorescent stains for histochemistry and cytochemistry and can provide a wide variety of information about the in situ content, molecular structure, conformation and environment of many nucleic acid–containing cell constituents.1 • Fluorescence photobleaching of DNA that has been photolytically labeled wit...

Myotonic dystrophy type 1 (DM1) is a triplet repeating disorder caused by expanded CTG repeats in the 3'-untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. The transcribed repeats fold into an RNA hairpin with multiple copies of a 5'CUG/3'GUC motif that binds the RNA splicing regulator muscleblind-like 1 protein (MBNL1). Sequestration of MBNL1 by expanded r(CUG) repeats...

The molecular structure of the DNA A-tract dodecamer d(CGCAAATTTGCG) complexed with the drug Hoechst 33258 has been determined by X-ray diffraction analysis. The Hoechst molecule binds in the DNA minor groove covering the sequence AATTT of the central A-tract, with the piperazine group close to one of the GC regions. The drug molecule makes two three-centered hydrogen bonds from the nitrogen at...

In order to easily assess growth and destruction of Toxoplasma gondii in vitro, this report describes two double staining assays that both visualize live and dead organisms: acridine orange--ethidium bromide (AO-EB) and bisbenzimide (Hoechst 33258)--propidium iodide (B-PI). EB and PI were chosen for dead organisms staining while AO and B stain viable organisms. Thus, both double staining assays...

The cortical endoplasmic reticulum (ER) of sea urchin eggs was localized on isolated egg cortices by staining with aqueous suspensions of the dicarbocyanine "DiI." Immunofluorescence localization of a calsequestrin-like protein was essentially identical; this is consistent with a role for the ER in calcium regulation. The ER often encircles cortical granules, making it well-suited for initiatin...

We compare the fluorescence properties of bisbenzimide (also known as Hoechst 33258) bound to the minor groove of the poly[d(AT)].poly[d(AT)] duplex with the corresponding fluorescence properties of bisbenzimide dissolved in neat organic solvents and mixed organic/aqueous solvents. Based on these comparisons, we conclude that the minor groove of the bisbenzimide-poly[d(AT)].poly[d(AT)] complex ...

Here, we observed the uptake of membrane-impermeant molecules by cercariae as they penetrate the skin and are transformed into schistosomula. We propose that membrane-impermeant molecules, Lucifer Yellow, Propidium iodide and Hoechst 33258 enter the parasite through both thenephridiopore and the surface membrane and then diffuse throughout the body of the parasite. We present a hypothesis that ...

The nuclei of preimplantation mouse embryos were identified after labelling with either DAPI or Hoechst 33258. During the 4- and 8-cell stages the peripherally located nuclei become clustered nearer the centre of the embryo. This nuclear migration towards the base of each cell was also observed during the development of couplets of 2/4 and 2/8 cells. Most blastomeres isolated from compact 8-cel...