Why use nigrosin

Place a very small drop more than a loop full, less than a free falling drop from the dropper of nigrosin near one end of a well-cleaned and flamed slide. Remove a small amount of the culture from the slant with an inoculating loop and disperse it in the drop of stain without spreading the drop.

Use another clean slide to spread the drop of stain containing the organism using the following technique. Rest one end of the clean slide on the center of the slide with the stain. Tilt the clean slide toward the drop forming an acute angle and draw that slide toward the drop until it touches the drop and causes it to spread along the edge of the spreader slide.

Maintaining a small acute angle between the slides, push the spreader slide toward the clean end of the slide being stained dragging the drop behind the spreader slide and producing a broad, even, thin smear. Focus a thin area under oil immersion and observe the unstained cells surrounded by the gray stain. Save my name and email in this browser for the next time I comment. Examine all three slides under oil immersion and record your results on your worksheet.

Methylene blue is a simple and direct stain used for determining bacterial morphology shape and arrangement.

It is a cationic dye positive charge which stains the cell a blue color. Hold the slide in an angle and rinse gently with water from the squirt bottle. The Gram stain is the most important and universally used staining technique in the bacteriology laboratory. Use the slides that you already prepared 1 S. Prepare an emulsion on each slide: If you are taking a bacteria from a plate, place a small drop of water on a slide and aseptically add bacteria.

If you are taking a bacteria from a broth, place loopfuls of bacteria onto a slide with no water added. You and your lab partner will need to prepare the following slides: 3 slides of Staphylococcus epidermidis one for simple stain, one for gram stain, one as back-up 3 slides of Pseudomonas aeruginosa one for simple stain, one for gram stain, one as back-up 2 slides of S. Skip to main content. This service is more advanced with JavaScript available.

Advertisement Hide. Eosin-Nigrosin Staining Procedure. Chapter First Online: 26 July This is a preview of subscription content, log in to check access. Open image in new window. Evaluation of the one-step eosin-nigrosin staining technique for human sperm vitality assessment. Hum Reprod.