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DNA 교잡에 의한 토양 미생물 군집의 다양성과 유사성
최영길(Yong Keel Choi),김유영(You Young Kim),송인근(In Geun Song),민병례(Byeong Rye Min),조홍범(Hong Bum Cho) 한국환경생물학회 1999 환경생물 : 환경생물학회지 Vol.17 No.3
To investigate soil bacterial diversity according to vegetation types, directly extracted DNA from 5 different soils were cross-hybridized with each other as a probe and target. Pinus densiflora soil was shown the highest value then agricultured soil>naked soil>grass soil>Quercus mongolicas soil in the order of diversity. Cluster analysis by similarity showed that soil microbial communities were categorized into three groups. [Soil bacterial community, DNA:DNA hybridization, Diversity].
김강영,최영길 ( Kang Young Kim,Yong Keel Choi ) 한국하천호수학회 1990 생태와 환경 Vol.23 No.2
In order to clarify the effects of heavy metals on cellulose degradation by aquatic bacteria, highest cellulolytic bacterium was isolated and determined minimum inhibitory concentrations of 7 metal ions (As, Cd, Cr, Hg, Mn, Ni, Pb). Cellulolytic bacteria were about 20∼90% ranges among total heterotrophic bacteria at 5 sites in Han River. Psuedomonas fluorescens was identified the highest cellulolytic bacterium. Minimum inhibitory concentrations of each metal ions in tested strain were As, 5.0; Cd, 0.125; Cr, 1.25; Hg, 0.00625; Mn, 1.25; Ni, 0.5; and Pb, 1.25 mM, respectively. Treated heavy metal ions were decreased cellulolytic activity as follows: Hg, 75∼80%; Cd, 50∼55%; Cr, 45∼52%; Pb, 36∼45%; As, 32∼34%; Ni, 22∼29 %, and Mn 13∼22%, respectively.
수계 중금속의 미생물학적 처리 - 균주 개량에 관한 연구 -
이희준,최영길 ( Heu Joon Lee,Young Keel Choi ) 한국환경생물학회 1993 환경생물 : 환경생물학회지 Vol.11 No.2
Two strains of yeasts, HYM 40 and HYM 20 which have resistance against heavy metals such as cadmium and lead and have ability to accumulate the heavy metals were isolated in the Han river and industrial sewage. These yeasts were identified as Torulopsis inconspicua. These strains can accumulate lead up to 180㎎/g dried cell and cadmium up to 147.5㎎/g dried cell. In the electron microscopic analysis, it was found that these heavy metals were in the cell wall. In order to compare the wild types with the amino acid auxotroph mutants in accumulation ratio, in case of cadmium, mutant M-3 accumulated 43.65% after 2 hours incubation and wild type did 31.64% after 4 hours incubation. On the other hand, mutant M-3 accumulated lead up to 79.18% and wild type did up to 37.22% after 2 hours, 4 hours incubation, respectively. On the basis of these results, when M-2 and M-3 were treated with 40% of PEG and 30mM of CaCl_2 for protoplast fusion, F-l accumulated cadmium up to 46.81% within 4 hours and lead up to 85. 63% within 2 hours. These results represent improvement of heavy metal accumulating abilities. When compared with original strain, this fusant shows 46% of increase rate in case of cadmium and 118% in case of lead.
수계 세균 군집의 세포외 효소 활성도 및 형태적 변화에 미치는 산성화의 영향
안영범,조홍범,최영길 ( Young Beom Ahn,Hong Bum Cho,Yong Keel Choi ) 한국환경생물학회 1997 환경생물 : 환경생물학회지 Vol.15 No.2
The effects of acidification on extracellular enzyme activities and morphological changes of bacteria were analyzed in the continuous microcosm. The activities of various extracellular enzyme such as lipase, phophatase, amylase, cellulase, β-glucosidase and chitinase showed the ranges of 0.022-1.811 μM/ℓ/hr. Enzymatic activities showed lower at pH 3 than at pH 7 and then sustained 4∼74% at lower pH values. As electron microscopy, bacterial cell surface has been pitted and covered with electron-dense fibrils and granules according to acidification. Also, inner layer of cell membrane was produced electron-dense granules, but cytoplasm and nuclear materials were not significantly change at all pH ranges. The cytological changes in the heterotrophic bacterial cells by the acidification correlate also with changes in activity of extracellular enzymes.
연속식 다단계 microcosm 에서 수계 세균 군집 및 세포외 효소 활성도 변화에 미치는 산성화의 영향
안영범,조홍범,최영길 ( Young Beom Ahn,Hong Bum Cho,Yong Keel Choi ) 한국환경생물학회 1998 환경생물 : 환경생물학회지 Vol.16 No.1
To define the effects of acidification on physicochemical factors, bacterial numbers, functional groups of bacteria and extracellular enzyme activities were analyzed in the continuous multistage microcosm. The concentrations of nitrate, nitrite, phosphate and soluble sugar were decreased and ammonia and heavy metal were increased as pH became lower. The total bacterial numbers of heterotrophic bacteria including functional groups of bacteria showed the ranges of 5.6∼16. 2 × 10 exp (5) cells/㎖ and 0.07 ∼ 32.47 × 10 exp (4) CFU/㎖ at various pH values, respectively. There were no significant correlation between total bacteria and water pH, but viable counts of heterotrophic bacteria decreased as pH became lower. The activities of extracellular enzyme showed the ranges of 0.022 ∼ 1.811 μM/ℓ/hr in continuous multistage microcosm. Activities decreased rapidly down to the pH 5. The continuous multistage microcosm was useful system to examine simulation analysis of acidification. The effects accompanied the changes of structures and functions of bacterial communities in aquatic ecosystem.
Plychlorinated biphenyl ( PCB ) 분해균주의 분리·동정 및 특성에 관한 연구
서영은,조홍범,최영길 ( Young Eun Suh,Hong Bum Cho,Yong Keel Choi ) 한국하천호수학회 1991 생태와 환경 Vol.24 No.2
The ratios of PCB degrading bacteria to heterotrophic bacteria were about 0.035%∼0.444% in Han River and Anyang stream. The highest ratio was found at Gunpo bridge in Anyang stream into which plants` effluents has been directly releasing. The two isolates capable of degradading Aroclor 1254, one of the PCB mixtures, were identified as Pseudomonas sp.. GS5, one of the two isolates, in the ability of biodegradation of Aroclor 1254 shown the degradation rate of 18%, 34%, 68% and GS6, the other isolate 2%, 28% 56% during 3, 6, 9 days, respectively. While the mixed culture of isolates had not influenced the ability of degradading Aroclor 1254, the isolates showed two times of degradading ability when biphenyl was added to it. The genes encoding enzymes of Aroclor 1254 degradation were located at plasmid and chromosome in the case of GS5 and GS6, respectively.
신성화에 따른 수계 세균 군집 및 세포외 효소의 활성도 변화
안영범,조홍범,최영길 ( Young Beom Ahn,Hong Bum Cho,Yong Keel Choi ) 한국하천호수학회 1997 생태와 환경 Vol.30 No.3
Physicochemical factors, functional populations of bacteria and their extracellular enzyme activities were analyzed in the bioreactor in order to observe the effects of acidification in Wangsong reservoir, Kyonggi-Do during the summer of 1996. The concentrations of ammonia and nitrate decreased and soluble sugar and heavy metal increased as pH became lower. The numbers of total bacteria, heterotrophic bacteria including functional populations of bacteria showed the ranges of 4.37∼10.31×10^6 cells/ml and 0.02∼7.77×10^4 CFU/ml at various pH values in bioreactor. There were no significant correlations between total bacteria and water pH, but viable counts of heterotrophic bacteria decreased as pH became lower. The activities of extracellular enzyme skewed the ranges of 0.008∼0.292㎛/ℓ/hr in bloreactor system. Enzymatic activities decreased rapldly below pH 5 and then sustained 5∼38% at lower pH values. The functional populations of bacteria and their extracellular enzyme activities showed conspicuously positive correlation with pH (0.80∼0.93, p<0.01). So, there were interpreted by the direct effect of pH rather than indirect effect of various environmental factors.