Staining nile blue

Ostle, A., Holt, J.G., 1982. Nile blue A as a fluorescent stain for poly-b-hydroxybutyrate. 

Figure 2. Handsection of a processed cheese loaf stained for fat with Nile Blue. The fat fluoresces yellow (white in the image). The figure shows good resolution of the droplets with minimal sample preparation. Epifluorescence optics (x 650).

Figure 6. Ciyo-section of chocolate stained with Nile Blue. The fat (white areas) forms a continuous phase around protein particles and sugar crystals, (darker areas). Epifluorescence optics.(x 490).

Kim YB, Rhee YH, Heo GS, Kim JS (1996b) Poly-3-hydroxyalkanoates produced from Pseudomonas oleovorans grown with (o-Phenoxyalkanoates. Macromolecules 29 3432-3435 Kitamura S, Doi Y (1994) Staining method of poly(3-hydroxyalkanoic acids) producing bacteria by Nile blue. Biotechnol Tech 8 345-350... 

Fig 2 and 3 show granules of PHA inside Poly-P bacteria stained with Nile blue by bright field microscopy and by epyfluorescence microscopy,... 

Figure 2. Activated sludge (dark spots) stained with Nile blue (bri t field microscof )...

Therefore, a viable-colony staining method has been developed which involves the direct inclusion of the lipophilic dyes Nile red or Nile blue A in the agar medium. This method requires a very low dye concentration, does not affect cell growth and obviates the need to produce master plates. However, the viable-colony method is more applicable for screening Gram-negative bacteria than Gram-positive bacteria [8]. Moreover, this method has its own drawbacks such as the requirement for appropriate carbon sources for the cultivation... 

Figure 17.4 Primary screening profiie of bacteria based on Nile blue staining.

In this method, oxazine dyes like Nile blue A is used which exhibits a strong fluorescence under the fluorescence microscope (Ostle and Holt, 1982). Nile red can also be used to detect PHB in growing cultures (Spiekermann et al., 1999). However, during purification, the membrane surrounding PHB granules is lost, therefore, caimot be stained by this technique (Dawes and Senior, 1973). 

Stain used in biology it may be used with live or fixed cells, and imparts a blue colour to cell nuclei. Derivatives of Nile blue are potential photosensitisers in photodynamic therapy of malignant tumours. 

FIGURE 4 Nile blue sulphate staining of Halomonas cells showing bright orange fluorescence of PHA granules (Kulkami 2010). 

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