vastuvärvimine

Vastuvärvimine, also known as counterstaining, is a laboratory technique used in microscopy to make structures more visible. It is often employed in conjunction with a primary stain. While the primary stain colors certain cellular components, the counterstain colors other structures that did not take up the primary stain, or that took it up weakly. This contrast allows for better differentiation and visualization of different parts of a specimen.

The choice of primary stain and counterstain is crucial and depends on the type of specimen being examined and the specific structures of interest. For example, in the Gram stain, a differential staining technique used to classify bacteria, crystal violet is the primary stain, and safranin is the counterstain. Gram-positive bacteria retain the crystal violet, appearing purple, while Gram-negative bacteria lose the crystal violet and are then colored by the safranin, appearing pink or red.

Vastuvärvimine is a common practice in histology, microbiology, and cytology. It enhances the clarity of images produced by light microscopy, allowing researchers to identify cellular morphology, identify microorganisms, or detect abnormalities in tissues. The effectiveness of vastuvärvimine relies on the differential affinity of cellular components for the various stains used, often based on chemical properties like charge and lipid content.