SYMPOSIA PAPER Published: 01 January 1985
STP33582S

Comparison of Techniques for Evaluating the Effect of Cadmium on

Source

Three techniques were compared in a study of the effect of cadmium on an aquatic strain of Pseudomonas fluorescens. The methods used were (1) direct microscopic counts using epifluorescence and formazan detection, (2) determination of colonyforming units, and (3) determination of intracellular adenosine triphosphate (ATP) using a firefly luciferase bioluminescent assay. Results of the plate count and ATP determinations demonstrated that P. fluorescens was stressed after exposure to 10-, 25-, 50-, and 100-ppm cadmium. The organisms recovered following treatment; however, only the ATP bioassay data indicated that there might be bacterial recovery at 12 h after the addition of 100-ppm cadmium. The acridine orange 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chlorine (INT) formazan reduction technique did not produce results that could be readily interpreted. The bacteria tended to clump together, and cells that had been exposed to 100-ppm cadmium generally did not fluoresce. In addition, it was not possible to detect formazan deposits in any of the cadmium-treated cells. Compared to the plate count procedure and the acridine orange INT-formazan reduction technique, the intracellular ATP assay appeared to be a more accurate method of determining the viability of P. fluorescens cells following cadmium treatment.

Author Information

Seyfried, PL
University of Toronto, Ontario, Canada
Horgan, CBL
University of Toronto, Ontario, Canada
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E47
Pages: 310–320
DOI: 10.1520/STP33582S
ISBN-EB: 978-0-8031-4952-6
ISBN-13: 978-0-8031-0437-2