Chapter 6, Problem 1Q

Why is the size more accurate in a negative stain than in a direct stain?

Summary Introduction

To write:

The reason for the more accurate size in a negative stain than in a direct stain.

Introduction:

Staining is a method which provides variance to the microscopic image for enhanced vision under the microscope. It is a method which is extensively used for the assessment of cells and tissues components. It is often used to draw attention to the microbial structures for viewing with the help of diverse microscopes.

Explanation of Solution

Smear:

It is a sample of bacterial cells or blood that is spread on a slide for the microscopic test or on the exterior of a culture medium.

Heat fixing:

After the drying of smear at the room temperature on the slide. This slide is gripped with the help of tongs or a clothespin. Then it is passed across the flame of a Bunsen burner and numerous times to heat-kill. It attaches the organism to the slide. Heat fixation usually conserves generally the morphology but not an internal structure.

Negative staining is a known method that is frequently used in the analytical microscopy. This staining method contrasts an optically opaque fluid with a thin specimen. In this method, the surroundings are stained and leave the actual specimen unaffected. Thus the specimen is visible.

The reason for the more accurate size in a negative stain than in a direct stain:

As negative staining does not involve the heat fixing but use the optically opaque fluid. The heat fixing distorts the cell shape. Thus, the size is more accurate in a negative stain.

Conclusion

The heat fixing distorts the cell shape. Thus, the size is more accurate in a negative stain.