• Title/Summary/Keyword: INT-dehydrogenase Activity

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Relationship between Toxicity of Heavy Metals and Sludge Retention Time in Sequencing Batch Reactor Process (연속회분식반응조 공정에서 슬러지 체류시간과 중금속 독성의 관계)

  • Kim, Keum-Yong;Cho, Young-Cheol;Lee, Sang-Ill
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.3
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    • pp.283-288
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    • 2007
  • In order to elucidate the relationship between the sludge retention time(SRT) and the toxicity of heavy metals, such as copper (Cu), cadmium(Cd), and zinc(Zn), in sequencing batch reactor(SBR) process, IC50 was estimated with measuring of INT-dehydrogenase activity in variable SRTs. When the concentrations of heavy metals were increased, the activity of INT-dehydrogenase was gradually decreased indicating the heavy metals inhibit bacterial activity. Cu showed higher toxicity than Zn and Cd. $IC_{50}$ of Cu, Cd, and Zn ranged from $0.37\sim1.96$ mg/L, $15.4\sim16.9$ mg/L, and $9.70\sim23.4$ mg/L, respectively. The toxicity of Cu and Zn was reversely proportional to the length of SRT. It is probably caused by the increased concentration of extracellular polymeric substances in longer SRT which absorb heavy metals. Therefore, the operation of SBR with increased SRT is desirable in treatment of industrial wastewater containing heavy metals.

Study on the Performances and Microbial Community in the Biofilm Process for Treating Nonpoint Source Pollutants (비점오염물질 처리를 위한 생물막 공정의 운전 및 미생물 군집의 특성)

  • Choi, Gi-Choong;Park, Jeung-Jin;Kang, Du-Kee;Yu, Jae-Cheul;Byun, Im-Gyu;Shin, Hyun-Suk;Lee, Tae-Ho;Park, Tae-Joo
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.10
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    • pp.1021-1027
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    • 2008
  • In this study, biofilm process was introduced for treating nonpoint source pollutants. The ceramic media were provided for biofilm growth in the reactors. The packing ratio of ceramic media was 5% and 15(v/v)%, respectively. Thereafter, the reactors were operated intermittently with the different interevent periods such as 0, 5, 10 and 15 days, respectively. The removal efficiencies of COD and NH$_4{^+}$-N were investigated at the different operating conditions such as media packing ratio, temperature, and interevent period. Additionally, Polymerase chain reaction(PCR)-denaturing gel gradient electrophoresis(DGGE) and INT-dehydrogenase activity(DHA) test were conducted to observe the microbial community and activity in the biofilm. Consequently, the interevent period seemed to have no significant influence on the COD removal efficiency. COD was removed within 6$\sim$8 hours at 25$^{\circ}C$ and about 15 hours at 10$^{\circ}C$. DGGE profiles showed that the initial species of microorganisms were changed from seeded activated sludge into the microorganisms detected in sediments. INT-DHA test also showed that the activities of microorgnaisms were not decreased even in the 15 days of interevent period.

Measurement of Ammonia Inhibition of Activated Sludge by DHA-INT (DHA-INT를 이용한 활성슬러지의 암모니아 저해도)

  • Lee, Sang-Min;Jung, Jin-Young;Chung, Yun-Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.11
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    • pp.1969-1976
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    • 2000
  • It is a time consuming work to identify the inhibition of unknown chemicals or industrial wastewater. Thus it is needed to establish a fast assay tool for finding a toxicant source. Biomass activity and ammonia inhibition were measured by DHAINT method. Ammonia inhibition tests were comprised of total ammonia inhibition and free ammonia inhibition. Those inhibitions were carried out by nitrifier and heterotroph each other with nitrifier inhibitor. The ammonia inhibition was proportional to an amount of total ammonia and pH increase. It meaned that a free ammonia played a key role for ammonia inhibition. however both total ammonia and free ammonia should be considered for an accurate assay of the ammonia inhibition. Nitrifier was more sensitive than heterotroph when the ammonia concentration above 3.000mg/L.

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Effect of Oxidative Stress and Glutamate Receptor Antagonist on Cultured Rat Osteoblast and Osteoclast (백서의 배양 골아세포와 파골세포에 대한 산화적 손상과 Glutamate 수용체 길항제의 영향)

  • Park Seung Taeck;Jeon Seung Ho;Lee Byung Chan
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.4
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    • pp.996-1001
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    • 2003
  • It is well known that oxidative stress of reactive oxygen species(ROS) may be a causative factor in the pathogenesis of bone disorder. The purpose of this study was to evaluate the cytotoxicity of oxidative stress. Cell viability by MTS assay or INT assay, activity of glutathione peroxidase(GPx), lipid peroxidation(LPO) activity and cell viablity. And also protctive effect of glutamate receptors against ROS-induced osteotoxicity was examined by protein synthesis, alkaline phosphatase (ALP) activity and lactate dehydrogenase (LDH) activity in cultured rat osteoblasts and osteoclasts. XO/HX decreased cell viability and GPx activity, protein synthesis and ALP activity, but increased LPO activity and LDH activity. In the protective effect, N-methyl-D-aspartate (NMDA) receptor antagonists or AMPA/kainate receptor antagonists such as D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), NMDA receptor antagonists but AMPA/kainate receptor antagonists showed protective effect on xanthine oxidase (XO) and hypoxanthine (HX) in these cultures by the increse of protein synthesis, ALP activity.

Sulforhodamine B Assay to Determine Cytotoxicity of Vibrio vulnificus Against Human Intestinal Cells

  • Lee, Byung-Cheol;Choi, Sang-Ho;Kim, Tae-Sung
    • Journal of Microbiology and Biotechnology
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    • v.14 no.2
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    • pp.350-355
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    • 2004
  • Sulforhodamine B (SRB) assay is a rapid, sensitive, and inexpensive method for measuring cell proliferation and chemosensitivity. However, the lactate dehydrogenase (LDH) release assay is generally used to measure cytototoxicity of infectious microorganisms against host cells. In this study, we investigated the possibility of applying the SRB assay to determine cytotoxicity for infectious microorganisms, and compared the results with those obtained by the LDH release assay. We used Vibrio vulnificus as a model of infectious microorganisms. The SRB assay showed that V vulnificus strongly induced cytotoxic activity against human intestinal cells, Caco-2 and INT-407 cells. The degree of cytotoxicity closely correlated with infection time and number ratios of V. vulnificus to intestinal cells (MOI, multiplicity of infection). Furthermore, cytotoxicity values obtained by SRB assay correlated well with results obtained by the LDH release assay, and both assays gave a linear response with respect to MOI Heat-inactivation of V. vulnificus for 35 min at $60^{\circ}C$ did not induce cytotoxic activity, indicating that viability of V. vulnificus is crucial for cytotoxic activity against intestinal cells. Although both assays are suitable as cytotoxicity endpoints, the SRB assay is recommended for measuring cytotoxicity of infectious microorganisms against host cells because of its significantly lower cost and more stable endpoint than the LDH release assay.

Application of Biological Activated Carbon Process for Water Quality Improvement of Stagnant Stream Channels

  • Lee, Jae-Ho;Park, Jeung-Jin;Park, Tae-Joo;Byun, Im-Gyu
    • Environmental Engineering Research
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    • v.19 no.4
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    • pp.309-316
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    • 2014
  • The water quality improvement of golf course ponds, as representative stagnant stream channels, was evaluated by applying a biological activated carbon (BAC) process composed of four consecutive activated carbon reactors. The study was performed from autumn to winter in order to evaluate the feasibility of the BAC process under low temperature conditions. In the study, water quality of pond A (target pond) and pond B (reference pond) were monitored. Pond water was pumped into the BAC process, and was then returned to the pond after treatment. The optimal conditions were determined to be 2 hr of empty bed contact time (EBCT) at a temperature above $4^{\circ}C$, in which improvements of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) of pond A compared to pond B were 3.62%, 3.48% and 1.81%, respectively. On the other hand, as the temperature was below $4^{\circ}C$, some degree of water quality improvement was achieved even when EBCT were 1 or 0.5 hr, suggesting that the BAC process can be successfully applied for the improvement of pond water quality in winter months. The values of biomass concentration and microorganism activity in each condition were highest where 2 hr of EBCT was applied at a temperature above $4^{\circ}C$, but values were similar throughout all treatment conditions, and thus, adsorption is considered to be the dominant factor affecting process efficiency. From the denaturing gel gradient electrophoresis (DGGE) results, no significant differences were observed among the activated carbon reactors, suggesting that the number of reactors in the system could be decreased for a more compact application of the system.