Which fluorochrome is used in fluorescent staining techniques to identify microorganisms rapidly?

The correct choice for identifying microorganisms rapidly using fluorescent staining techniques is biotin-avidin. This technique leverages the strong binding affinity between biotin and avidin, which allows for a highly sensitive detection method. In this approach, microorganisms can be tagged with biotin-labeled antibodies, and then avidin or streptavidin conjugated to a fluorescent marker can be used to bind to the biotin. This creates a signal that can easily be detected with fluorescence microscopy, making it an effective means for rapid identification.

Fluorescein, while also a fluorochrome, is primarily used in other staining applications, such as in immunofluorescence assays and generalized cell visualization. It would not be as specific for microorganism identification as the biotin-avidin method.

DAPI is a fluorochrome that binds specifically to DNA and is often used for nuclear staining rather than for targeted identification of specific microorganisms. It’s particularly useful in cell cycle studies and cell viability assessments.

Rhodamine B is another fluorescent dye that can stain cellular components but is typically used for visualization rather than rapid identification of specific microorganisms in a more targeted or specific manner compared to the biotin-avidin method.

Therefore, biotin-avidin