Texas red

Fig. IV-19. Fluorescence micrographs showing the shape transitions in monolayers of dimyristoylphosphatidylcholine (DMPC) (84%) and dihydrocholesterol (15%) and a lipid containing the dye, Texas Red. (From Ref. 228.)...

Consumers expectations depend on several factors including cultural background, past experiences, desire for color coordination, esthetic appeal, local customs, fads, etc. Thus, eg, a Texas red hot sold ia the South is often colored quite differently than one sold ia the North, Midwesterners prefer butter with a deep yellow color, and on birthdays the decoration on a boy s cake are often blue and those on a gid s are often pink. 

The transfection mechanism of plasmid-chitosan complexes as well as the relationship between transfection activity and cell uptake was analyzed by using fluorescein isothiocyanate-labeled plasmid and Texas-Red-labeled chitosan. Several factors affect transfection activity and cell uptake, for example the molecular mass of chitosan, stoichiometry of complex, seriun concentration and the pH of the transfection medium. The level of transfection with plasmid-chitosan complexes was found to be highest when the molecular mass of chitosan was 40 or 84 kDa, the ratio of chitosan nitrogen to DNA phosphate was 5, and serum at pH 7.0 was 10%. Plasmid-chitosan complexes most likely condense to form large aggregates (5-8 p,m), which absorb to the cell surface. After this, plasmid-chitosan complexes are endocytosed, and accumulate in the nucleus [97]. 

Fig. 3 Polypeptide vesicle with endocytosis capability, (a) Vesicles formed from poly(L-arginme)6o-h-poly(L-leucme)2o- The poly(L-arginme) block provides an added cell-penetrating feature to the vesicles, (b, c) LCSM images of internalized vesicles (green) containing Texas-Red-labeled dextran (red) in (b) epithelial and (c) endothelial cells. Colocalization of the vesicles and Texas-Red-labeled dextran appears as a yellow fluorescent signal. Adapted from [44] with permission.Copyright 2007 Macmillan Publishers...

Wippersteg V, Ribeiro F, Liedtke S et al (2003) The uptake of Texas Red-BSA in the excretory system of schistosomes and its colocalisation with ER60 promoter-induced GFP in transiently transformed adult males. Int J Parasitol 33 1139-1143... 

Alternatively, proteins can be labeled selectively using amine-reactive dyes. Particularly, cysteine and lysines can be modified covalently with a variety of commercially available fluorophores including Texas Red, Oregon Green, and Cy3 [19] (see also Chapter 6 for small molecule FRET probes, and Chapter 12 depicting a variety... 

Since endocytosis ofLDH was confirmed by TEM images (Figure 13.9), forthe next step, its specific endocytic pathway for membrane entry was determined by immunofluorescence and confocal microscopy. Cells were incubated with LDH-FITC, fixed with 3.7% freshly made formaldehyde, and then stained with either anti-clathrin antibody or anti-caveolin-1 antibody both conjugated to the red fluorescent dye Texas Red (TR). The confocal microscopic images showed that green fluorescent... 

Dabcyl-N-succinimidyl ester aminofluorescein Texas Red hydrazide... 

Fig. 13 Uptake of OVA-encapsulating y-PGA-Phe nanoparticles by DCs. DCs were incubated with Texas Red-labeled OVA (TR-OVA) alone (a) or TR-OVA encapsulated within fluorescein-labeled nanoparticles (TR-OVA/FITC-NPs) (b). The intracellular localization of OVA (red) and NPs (green) was observed by confocal laser scanning microscopy...

Four forms of amine-reactive rhodamine probes are commonly available. Two of them are based on the tetramethyl derivatives of the fundamental rhodamine structure, one is based on the sulforhodamine B or Lissamine derivative, and the last is the sulforhodamine 101 or Texas Red-type of derivative. All of them react under alkaline conditions with primary amines in proteins and other molecules to form stable, highly fluorescent complexes. 

Figure 9.17 Texas Red sulfonyl chloride can be used to label amine-containing molecules through sulfonamide bond formation.

The intense Texas Red fluorophore has a QY that is inherently higher than the tetrameth-ylrhodamine or Lissamine rhodamine B derivatives. Texas Red s luminescence is shifted maximally into the red region of the spectrum, and its emission peak only minimally overlaps with that of fluorescein. This makes Texas Red derivatives among the best choices of labels for use in double-staining techniques. 

Texas Red sulfonyl chloride is soluble in DMF or acetonitrile and may be dissolved as a concentrated stock solution in either solvent prior to the addition of a small aliquot to an aqueous reaction medium. Avoid the use of DMSO, as sulfonyl chlorides react with this solvent (Boyle, 1966). The solid and all solutions made from it must be protected from light to avoid photodecomposition. Prepare the stock solution immediately before use. 

Dissolve Texas Red sulfonyl chloride (Thermo Fisher, Invitrogen) in acetonitrile at a concentration of 20 mg/ml. Prepare fresh and protect from light. Use a fume hood for all operations using organic solvents. 

In subdued lighting conditions, add 50 pi of the Texas Red sulfonyl chloride solution to each ml of the protein solution. Mix well. 

At the time of this writing, over 15,000 references cited the use of Texas Red for labeling biological molecules or in bioconjugate detection applications. 

Figure 9.20 Texas Red hydrazide reacts with aldehydes to create hydrazone bonds.

In addition to the wide range of commercial probes, many other fluorescent molecules have been synthesized and described in the literature. Only a handful, however, are generally used to label antibody molecules. Perhaps the most common fluorescent tags with application to immunoglobulin assays are reflected in the main derivatives produced by the prominent antibody manufacturing companies. These include derivatives of cyanine dyes, fluorescein, rhod-amine, Texas red, aminomethylcoumarin (AMCA), and phycoerythrin. Figure 20.16 shows the reaction of fluorescein isothiocyanate (FITC), one of the most common fluorescent probes, with an antibody molecule. 

Modification of (strept)avidin with Texas Red sulfonyl chloride may be done similarly, except the fluorophore is first dissolved in acetonitrile prior to addition to the aqueous reaction mixture. 

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