• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.395-399
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• 2000

Five different freeze-dried recombinant bioluminescent bacteria were used for the detection of cellular stresses caused by endocrine disrupting chemicals. These strains were DPD2794 (recA::luxCDABE), which is sensitive to DNA damage, DPD2540 (fabA::luxCDABE), sensitive to cellular membrane damage, DPD2511 (katG::luxCDABE), sensitive to oxidative damage, and TV1061 (grpE::luxCDABE), sensitive to protein damage. GC2, which emits bioluminescence constitutively, was also used in this study. The toxicity of several chemicals was measured using GC2. Damage caused by known endocrine disrupting chemicals, such as nonyl phenol, bisphenol A, and styrene, was detected and classified according to toxicity mode, while others, such as phathalate and DDT, were not detected with the bacteria. These results suggest that endocrine disrupting chemicals are toxic in bacteria, and do not act via an estrogenic effect, and that toxicity monitoring and classification of some endocrine disrupting chemicals may be possible in the field using these freeze-dried recombinant bioluminescent bacteria.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.171-175
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• 2018

Quorum sensing (QS) is a cell density-dependent communication mechanism between bacteria through small signaling molecules. When the number of QS signaling molecules reaches a threshold, they are transported back into the cells or recognized by membrane-bound receptors, triggering gene expression which affects various phenotypes including bioluminescence, virulence, adhesion, and biofilm formation. These phenotypes are beneficial for bacterial survival in harsh environments. This review summarizes the application of QS inhibitors for control of biofilm formation and virulence expression of periodontal pathogens.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.174.2-174.2
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• 2003

Quorum sensing, a gene expression in response to population density, is regulated by chemical signals, most of which are acylated homoserine lactones (AHLs). The AHL derivatives have been reported to regulate bioluminescence, virulence factors and / or swarming motility in bacteria. It is hypothesized that higher organisms may have evolved specific means to interfere with bacterial communication as exemplified in the AHL-antagonistic activity of halogenated furanones isolated from the Australian macroalga Delisea pulchra. (omitted)

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.8-15
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• 2010

An experiment was conducted to evaluate the biologically adverse effect of increased carbon dioxide in seawater on marine bacteria, Vibrio fischeri. We measured the bioluminescence and cell density at every 6 hours for 24 hours of the whole incubation period after exposing test microbes to a range of $CO_2$ concentration such as 380(Control), 1,000, 3,000, 10,000 and 30,000 ppm, respectively. Significant effect on relative luminescence(RLU) of V. fischeri was observed in treatments with $CO_2$ concentration higher than 3,000 ppm at t=12 h. However, the difference of RLU among treatments significantly decreased with the incubation time until t=24 h. Similar trend was observed for the variation of cell density, which was measured as optical density using spectrophotometer. The results showed that a significant relationship between $CO_2$ concentration and bioluminescence of test microbes was observed for the mean time. However, the inhibition of relative bioluminescence and also cell density could be recovered at the concentration levels higher than 3,000 ppm. The dissolved $CO_2$ can be absorbed directly by cell and it can decrease the intracellular pH. Our results implied that microbes might be adversely affected at the initial growing phase by increased $CO_2$. However, they could adapt by increasing ion transport including bicarbonate and then could make their pH back to normal level. Results of this study could be supported to understand the possible influence on marine bacteria by atmospheric increase of $CO_2$ in near future and also by released $CO_2$ during the marine $CO_2$ sequestration activity.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1706-1712
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• 2006

Because of the need for new antimicrobial substances with novel mechanisms of action, we report here the use of an Acinetobacter reporter system for high-throughput screening of active antimicrobial agents. The bioreporter Acinetobacter strain DF4/PUTK2 carrying luciferase genes luxCDABE was chosen because of its ecological importance and it is widespread in nature. This bioreporter is genetically engineered to emit light constitutively that can be measured in real time by luminometry. Hence, this reporter system was employed to determine the bacteriostatic actions of spent-culture supernatants derived from twelve bacterial isolates. Out of the results, the strongest bioluminescence inhibitory effect of the supernatants was recorded with Bacillus cereus strain BAC (S5). Subsequently, ethyl acetate extracts of extracellular products of strain BAC (S5) were separated by a thin-layer chromatography (TLC). Based on the bioluminescence inhibitory assay, three fractions were found to have antimicrobial activity. One fraction (C) having the strongest antimicrobial activity was further purified using TLC and characterized by IR, $^1H$ NMR, mass spectrometry, SDS-PAGE, and amino acid composition analysis. The results predicted the presence of 2-pyrrolidone-S-carboxylic acid (PCA) and the octadeconic-acid-like fatty acid. Fraction C also demonstrated a broad inhibitory activity on several Gram-negative and Gram-positive bacteria. In conclusion, the Acinetobacter reporter system shows great potential to be a reliable, sensitive, and real-time indicator of the bacteriostatic actions of the antimicrobial agents.

• Korean Journal of Microbiology
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• v.36 no.1
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• pp.1-7
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• 2000

The genes involved in riboflavin synthesis (ribI, II, III, and IV) were found immediately downstream of luxG in the lux operon from Photobacterium species. The single stranded DNA containing the intergenic region of lux genes and rib genes from Photobacterium phosphoreum was fully protected by P. phosphoreum mRNA from the S1 nuclease mapping assay suggesting that a transcriptional terminator was not present in the region. In addition, the levels of riboflavin synthase activity in P. phosphoreum was increased during the development of bacterial bioluminescence in the same fashion as the luciferase and fatty acid reductase activities. Insertion of the Photobacterium leiognathi DNA extending from luxB to ribII, between a strong lux promoter and a reporter gene (chloramphenicol acetyltransferase, CAT) and transferred by conjugation into P. leiognathi, did not affect expression of reporter gene. Moreover the CAT gene was not expressed in an analogous construct missing the lux promoter indicating that a promoter was not present in this region. Based on the data here, it can be concluded that the lux genes and rib genes in Photobacterium species are under common regulation.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.187-190
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• 2000

Effects of gamma ionizing radiation on recombinant Escherichia coli cells containing stress promoters, recA, fabA, grpE, or katG, fused to luxCDABE originated from Vibrio fischeri were characterized by monitoring transcriptional responses reflected by bioluminescent output. Quantification of gamma-ray intensity may be possible using the recA and fabA promoter fusion since a linear enhancement of bioluminescence emission with increasing gamma-ray intensity was observed. Other strains sensitive to either oxidative stress (DPD2511, katG::luxCDABE) or protein-damaging stress (TV1061, grpE::luxCDABE) were also irradiated by gamma-rays, and resulted in no noticeable bioluminescent output while DPD2794 with recA promoter and DPD2540 with fabA promoter irradiated by the same intensities of gamma-rays gave a significant bioluminescent output. This indicates that the main stresses in the recombinant bacteria caused by ionizing radiation are DNA and membrane-damage, not protein- or oxidative-damage. In addition, in this study, to investigate the relationship between the radiation dose rate and bacterial responses, two recombinant Escherichia coli strains, DPD2794 and GC2, containing lac promoter fused to luxCDABE originating from Photorhapdus luminescences, were used for detecting DNA damage and cellular toxicity under various radiation dose rates. Throughout this study, it was found that these bacteria showed quantitative stress responses to DNA damage and general toxicity caused by gamma rays, depending on the radiation dose rates, indicating that the bacterial stress responses and general toxicity were seriously influenced according to radiation dose rates.

• Environmental Analysis Health and Toxicology
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• v.14 no.4
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• pp.135-144
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• 1999

Environmental toxicities of priority water pollutants were evaluated by two selected bioassays, Lettuce seed germination/elongation test and Microtox acute toxicity test. Toxic chemicals (heavy metals, polycyclic aromatic hydrocarbons, and phenolic compounds) inhibited the germination rate and root elongation of Lettuce seed, as well as the bioluminescence of Microtox bacteria. When test biota were exposed to target chemicals, the sensitivity of Lettuce bioassay was relatively lower than that of Microtox bioassay. However, Lettuce bioassay may be a good candidate for prescreening the environmental toxicities of priority water pollutants, since the testing method with Lettuce seed was relatively easier and more economic than with Microtox bacteria. Toxicity tests were conducted to compare the validity and sensitivity of both bioassays for sediment from a small stream passed through urban area as well as leachate from a municipal solid waste landfill. From experimental results, we found that Lettuce test and Microtox test are compensated each other as a battery of bioassay for evaluating the environmental toxicities of field samples obtained from a small stream contaminated by pollutants.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.3
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• pp.202-206
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• 2000

The genetically-engineered Escherichia coli strain, DPD2540, which contains a fabA:::luxCDAbefusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more pactical application of this strain in the filed as biosensor, freezedrying was adopted. A 12% surcrose solution with Luria-Bertani (LB) broth, as determined by the viability after freeze-drying, was found to be most most effective composition for lyophilization solution among various compositions testitons tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as compared to samples frozen at-7$0^{\circ}C$ and -2$0^{\circ}C$. The biosensing activities of the cells showed a greater sensitivity when the cells from the expontial phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in the biodencor field was determined.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.43-50
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• 2006

Bioreporter bacteria, such as recombinant bioluminescent bacteria, have been used for the detection of specific compounds in complex environmental media. In this study, optimum conditions for the preparation and application of deep-freezed and Iyophilized recombinant bioluminescent strain KG1206 were investigated for the future application on contaminated environmental sites. Genetically engineered microorganism, Pseudomonas putida mt-2 KG1206, contains TOL plasmid and the plasmid inserted $P_{m}$, promoter on the upper part of lux gone in vector pUCD615, and m-toluate and benzoate are considered direct inducers for bioluminescence. Optimum conditions determined for the preparation and application of the deep-freezed and lyophilized strain were followings: cryoprotective agent (24% sucrose), lyophilization time (12 hrs), strain concentration ($OD_{600}=0.6$), reconstitution for freezed strain (quick reconstitution at $35^{\circ}C$), reconstitution for lyophilized strain ($3{\sim}6$ hrs exposure on LB medium), carrying conditions (keep at $20^{\circ}C$ after reconstitution). These results demonstrate the feasibility of deep-freezed or lyophilized state of genetically engineered bioluminescent strain for environmental usage.