Automation of the Resazurin Reduction Test using Fluorometry of Microtitration Trays

Abstract

Microtitration plate technique and -fluorometry was applied to automate the resazurin reduction test for monitoring bacterial numbers in broth cultures and milk. The effect of resazurin and resorufin concentration, bacterial species, growth medium, pH, and redox potential on the fluorescence response was studied. The timing of the appearance of maximum fluorescence was directly related to the logarithm of the number of colony-forming units (log CFU). Fresh milk and heat-treated milk contain interfering redox systems. The technique based on microtitration plate fluorometry, when fully automated, seems to provide a high-capacity system for analyzing bacterial numbers in foodstuffs and other media.

Toxic lactonic lipopeptide from food poisoning isolates of Bacillus licheniformis

“…The column used was Sephasil C18 SC 2.1 mm inner diameter  100 mm, 5 mm. The eluent was a gradient of A, 50 mm triethylamine phoshate in water and B, acetonitrile from 90% A and 10% B to 50% B in 40 min, with flow rate of 150 mL´min 21 . For detection A 340 was used.…”

Growth kinetics of Mycobacterium tuberculosis measured by quantitative resazurin reduction assay: a tool for fitness studies

“…Resazurin is a redox indicator dye that is reduced to resorufin by metabolically active cells (1). There is a direct correlation between the reduction of resazurin in the growth medium and the quantity/proliferation of live organisms (9).…”

Isolation of Toxigenic Nocardiopsis Strains from Indoor Environments and Description of Two New Nocardiopsis Species, N. exhalans sp. nov. and N. umidischolae sp. nov

“…1 Based on the results presented above, isolates 123 and 704a were closest to N. alba subsp. alba, and isolate 64/93 was closest to N. dassonvillei subsp.…”

“…Reduction of resazurin by the spermatozoa was assayed fluorometrically (1). The dissipation of boar sperm cell mitochondrial ⌬ by methanol extracts was determined by selective staining with JC-1 as described by Peltola et al (42).…”