A novel continuous toxicity test system using a luminously modified freshwater bacterium.
An automated continuous toxicity test system was developed using a recombinant bioluminescent freshwater bacterium. The groundwater-borne bacterium, Janthinobacterium lividum YH9-RC, was modified with luxAB and optimized for toxicity tests using different kinds of organic carbon compounds and heavy metals. luxAB-marked YH9-RC cells were much more sensitive (average 7.3-8.6 times) to chemicals used for toxicity detection than marine Vibrio fischeri cells used in the Microtox assay. Toxicity tests for wastewater samples using the YH9-RC-based toxicity assay showed that EC50-5 min values in an untreated raw wastewater sample (23.9 +/- 12.8%) were the lowest, while those in an effluent sample (76.7 +/- 14.9%) were the highest. Lyophilization conditions were optimized in 384-multiwell plates containing bioluminescent bacteria that were pre-incubated for 15 min in 0.16 M of trehalose prior to freeze-drying, increasing the recovery of bioluminescence and viability by 50%. Luminously modified cells exposed to continuous phenol or wastewater stream showed a rapid decrease in bioluminescence, which fell below detectable range within 1 min. An advanced toxicity test system, featuring automated real-time toxicity monitoring and alerting functions, was designed and finely tuned. This novel continuous toxicity test system can be used for real-time biomonitoring of water toxicity, and can potentially be used as a biological early warning system.
Cho
Jang-Cheon
JC
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea. chojc@oregonstate.edu
Park
Kyung-Je
KJ
Ihm
Hyuk-Soon
HS
Park
Ji-Eun
JE
Kim
Se-Young
SY
Kang
Ilnam
I
Lee
Kyu-Ho
KH
Jahng
Deokjin
D
Lee
Dong-Hun
DH
Kim
Sang-Jong
SJ
D001681:Biological Assay / Q000295:instrumentation / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water / Q000382:microbiology; D008163:Luminescent Measurements / Q000379:methods*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009862:Online Systems; D015202:Protein Engineering / Q000379:methods; D020560:Proteobacteria / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013499:Surface Properties; D018675:Toxicity Tests / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity*
D008164:Luminescent Proteins; D014874:Water Pollutants, Chemical