• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.243-252
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• 2006

Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.79-84
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• 2008

This paper describes the application of bioluminescence stimulating agents on a genetically engineered microorganism, Pseudomonas putida mt-2 KG1206, to monitor toluene analogs using in groundwater samples from petroleum hydrocarbon contaminated sites. The maximum bioluminescent response with pure chemicals followed in the order: m-methyl benzyl alchohol > m-toluate > toluene > m-xylene > benzoate > p-xylene > o-xylene. Generally, the bioluminescence production of strain mixed with groundwater samples was dependent on the contaminated total inducer concentrations. However, few samples showed opposite results, where these phenomena may be caused by the complexicity of environmental samples. Two chemicals, SL(sodium lactate) and KNO$_3$, were tested to determine a better bioluminescence stimulant. Both chemicals stimulate the bioluminescence activity of strain KG1206, however, a slightly high bioluminescence was observed with nitrogen chemical. This selected stimulant was then tested on samples collected from contaminated groundwater samples. The bioluminescence activity of all samples mixed with the strain was stimulated with KNO$_3$ amendment. This suggests that the low bioluminescence activity exhibited by the environmental groundwater samples can be stimulated by amending the culture with a proper agent, such as nitrogen compound. These findings would be useful, especially, when strain was used to monitor the groundwater samples contaminated with low inducer contaminants. Overall, the results of this study found the ability of bioluminescence producing bacteria to biosensor a specific group of environmental contaminants, and suggest the potential for more efficient preliminary application of this engineered strain in a field-ready bioassay.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.154-161
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• 1998

To investigate whether the introduced genetic marker is useful to detect the survivalship and activity of the natural bacteria under the stressed conditions, one Gram-negative isolate, KP964 was transformed to the luminous phenotype by transferring luxAB gene. Under the starvation-stress this luminous bacterial culturability (determined by colony-forming-units [CFU] on agar plate) decreased rapidly below the detection limit by 37 days, while its total cell number (determined by AODC) remained almost the same as its initial inocular size. At that time period, the viable cell number was estimated to be 1400 times higher than its CFU number. The bioiuminescence (determined by relative light units [RLU]) produced under the same condition was also monitored and found to decrease more rapidly than the culturability by 5-fold. Under the other stresses, e.g., osmotic shocks, acid shock, and exposure to toxic chemicals, this bacterial strain did not show the reliable correlation between CFU and RLU. These results might not suggest the direct estimation of bioiuminescence from the stressed bacteria be an index of both the survivalship and its activity. However, when the stressed bacterial cells were incubated under the favorable condition by relieving from the existing stress, the potential bioiuminescence (the lag periods before the increase of bioiuminescence, the increase rates of bioiuminescence, and the maximal levels of bioiuminescence) was shown to be highly dependent upon the strengths of the stresses exposed to the bacterial cells. Therefore, analysis of the potential bioiuminescence from the stressed bacteria revealed good relationships with survival as well as activity.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.205-210
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• 2013

Lumazine protein is a fluorescent protein isolated from the bioluminescent bacteria of Photobacterium species. To generate minimal size of lumazine protein with possessing fluorescent characteristic, the gene coding for the wild type N-terminal domain of lumazine protein (N-LumP 118) containing amino acids up to 118 from Photobacterium leiognathi was produced. In addition, the genes coding for the variant proteins of N-LumP 118, replaced with one tryptophan amino acid (N-LumP 118 V41W, S48W, T50W, D64W, and A66W), were also constructed by Polymerase Chain Reaction and Site Directed Mutagenesis. These proteins were expressed in Escherichia coli by transformation with recombinant plasmids and purified by 6X-His tagging system. Spectroscopic studies have show that the purified proteins are capable of binding to the fluorescent ligand 6,7-dimethyl-8-ribityllumazine, resulted in showing of fluorescent characteristic with the minimal size of protein. From these studies, the mutant proteins containing single tryptophan amino acid residue, possessing its own intrinsic flouophore character at the different position, will be able to the use as a probe for further studies to deduce their three dimensional structure and the binding modes.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.419-424
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• 2009

To provide the basis of biosensor based on the lux genes from bioluminescent bacteria of Photobacterium leiognathi and Vibrio harveyi, we test the expression of lux genes in several strains of Escherichia coli. The expression of the recombinant plasmid of PlXba.pT7-3, containing all lux genes requiring for light emission without adding substrate, in E. coli 43R was so strong to see the blue-green light in single colony as well as in the alginate immobilized cell. In addition, the light intensity was decreased by adding heavy metal ion such as cadmium and zinc ions. These result raise the possibility that a biosensor can be developed using the lux genes system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.106-111
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• 2008

Six standard methods for marine ecotoxicological tests were established(or applicated) using marine decomposer, primary producers and consumers. Development processes referred to the standard methods established by USEPA(United States Environmental Protection Agency), international organizations and European methods. However, the standard test species were selected among the domestic species generally found in the Korean waters and sediments. The test methods provide the culture/maintenance of test species, test methods, reproducibility and quality acceptance criteria etc. A total of nine test species were designated including bioluminescent bacteria(Vibrio fischeri), diatom(Skeletonema costatum), seaweed(Ulva pertusa), rotifer(Brachionus plicatilis), benthic copepod(Tigriopus japonicus), benthic amphipods(Mandibulophoxus mai, Monocorophium acherusicum), and fishes(Oryzias latipes, Paralichthys olivaceus). These test species represent the decomposer, primary producer and consumers in marine trophic system in Korean coastal ecosystems, and we recommend the "battery test" including at least one species from the each trophic level for marine ecotoxicological test.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.1-9
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• 2022

The effect of sediments in a waste dumping area on marine organisms was evaluated using sediment toxicity tests with a benthic amphipod (Monocorophium acherusicum) and bioluminescent bacterium (Vibrio fischeri) in accordance with the Korean Standard Method for Marine Wastes (KSMMW). Nine sites in the East Sea-Byeong, East Sea-Jeong, and Yellow Sea-Byeong areas were sampled from 2016 to 2019. The test results showed that the relative average survival rate (benthic amphipods) and relative luminescence inhibition rate (luminescent bacteria) were below 30%, which were judged to be "non-toxic." However, in the t-test, a total of 12 benthic amphipod samples (6, 1, 1, and 4 in 2016, 2017, 2018, and 2019, respectively) were significantly different (p<0.05) from the control samples. To identify the source of toxicity on benthic amphipods, a simple linear regression analysis was performed between the levels of eight heavy metals (Cr, As, Ni, Cd, Cu, Pb, Zn, and Hg) in sediments and the relative average survival rate. The results indicated that Cr had the highest contribution to the toxicity of benthic amphipods (p = 0.000, R2 = 0.355). In addition, Cr was detected at the highest concentration at the DB-85 station and exceeded the Marine Environment Standards every year. Although the sediments were determined as "not toxic" according to the ecotoxicity criteria of the KSMMW, the results of the statistical significance tests and toxicity identification evaluation indicated that the toxic effect was not acceptable. Therefore, revising the criteria for determining the toxic effect by deriving a reference value through quantitative risk assessment using species sensitivity distribution curves is necessary in the future.