Development of a rapid positive/absent test for coliforms using sensitive bioluminescence assay.
We have developed a sensitive bioluminescence assay for beta-galactosidase using a luminescent substrate, D-luciferin-O-beta-galactopyranoside (LuGal). The detection limit for beta-galactosidase was 3 x 10-20 mol per assay, which was approximately 50-fold more sensitive than the test using a fluorescent substrate. This assay was applied to a positive/absent (P/A) test for coliforms. Observations made after 7 h of culture followed by a 10-min enzyme assay using LuGal were comparable to those made after a 22-24-h culture by the current method. Therefore, the LuGal method allows a rapid P/A test for coliforms.
Masuda-Nishimura
I
I
Research and Development Division, Kikkoman Corporation, Noda City, Japan.
Fukuda
S
S
Sano
A
A
Kasai
K
K
Tatsumi
H
H
D001431:Bacteriological Techniques; D015169:Colony Count, Microbial; D003470:Culture Media; D004755:Enterobacteriaceae / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification*; D049454:Firefly Luciferin / Q000378:metabolism; D005697:Galactosides / Q000378:metabolism; D008163:Luminescent Measurements; D012680:Sensitivity and Specificity; D013997:Time Factors; D001616:beta-Galactosidase / Q000378:metabolism
D003470:Culture Media; D005697:Galactosides; C080091:luciferin-O-galactopyranoside; D049454:Firefly Luciferin; D001616:beta-Galactosidase