The phenomenon noticed as a central area of altered shade inside a resazurin-based assay, particularly when a sulfur-containing compound is current, signifies a localized discount of the dye. Resazurin, a blue indicator dye, is transformed to resorufin, a pink compound, upon discount. Within the presence of a thiol, or a compound containing a sulfhydryl group (-SH), this discount can happen. The central area suggests the next focus of the thiol or a extra favorable surroundings for its exercise, resulting in a localized space of resorufin formation. For example, if micro organism producing hydrogen sulfide (H2S) are cultured within the presence of resazurin, the launched H2S can react to scale back the resazurin across the bacterial colony.
This localized discount might be essential in assessing the metabolic exercise of microorganisms or the presence of decreasing brokers. It supplies a visible and probably quantifiable methodology to detect the manufacturing or presence of sulfur-containing compounds. Traditionally, resazurin assays have been used as indicators of bacterial contamination in milk and different meals merchandise. The noticed sample is important because it permits for spatial decision of the decreasing exercise, differentiating it from a basic discount of all the resazurin answer.
