Anabaena cylindrica 분해세균의 분리 및 동정

최영길,홍엽,신규철,김민성,한명수,Choi, Yong-Keel,Hong, Yup,Shin, Kyu-Chul,Kim, Min-Seong,Han, Myung-Soo 한국미생물학회 2002 미생물학회지 Vol.38 No.2

To isolate the bacteria lysing cyanobacteria, the sediment samples were collected from Dochang and Pal'tang Reservoir and Seokchon Lake. Each sample was smeared on the Anabaena cylindrica lawn and incubated in light chamber for 11 days. Bacteria having cyanobacteria-Iysing activity were isolated from the samples of Seokchon reservoir. Confirmation of cyanobacteria-Iysing activity was carried out to measure chlorophyll a and bacterial cell counting in mixed culture of Anabaena cylindrica and bacteria. Lysis was detected when extracellular meterials was added to the Anabaena cylindrica culture. The isolate was identified by analysis based on 16S rDNA sequence and morphological and physiological properties. The bacterial strain was taxonomically studied by the phylogenetic analysis based on 165 rDNA sequence. This strain was identified as a member of the genus Bacillus and designated as Bacillus sp. CHS1. 남조류 분해세균을 분리하기 위하여 도창, 팔당 저수지와 석촌 호수로부터 저층시료를 채취하였다. Anabaena cylindrica lawn에 각각의 시료를 도말한 후 11 일간 배양하였고 석촌 시료를 접중한 Anabaena cylindrica lawn에서 Anabaena cylindrica에 분해능을 가지는 세균을 분리하였다. 분해능 화인은 남조류와 분해세균을 혼합한 후 chlorophyll a간의 측정과 분리세균의 cell counting방법으로 확인하였고, 세포외 물질이 Anabaena cylindrica를 분해하는 것을 확인하였다. 분리균주는 16S rDNA 염기서열 분석과 형태학적, 생리학적 특징을 기초로 하여 동정하였다. 분리균주의 165 rDNA염기서열을 기초로한 분자계통학적 분석을 통하여 Bacillus속에 포함하는 계통학적 그룹에 속한다는 것을 확인하였고, Bacillus sp. CHSl으로 명하였다.

수계종속 영양세균 군집의 종조성 및 세포의 효소의 변화에 미치는 산성화의 영향

최영길(Yong Keel Choi),한명수(Myung Soo Han),김세화(Se Wha Kim),이경(Kyung Lee),유광일(Kwang Il Yoo) 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.1

N/A In an artificial pH-gradient batch culture system, the author analyzed the effects of acidification on the species composition of heterotrophic bacteria. As the result of this study, it was found that the numbers of total bacteria were not affected by acidification and that the population size of heterotrophic bacteria decreased as pH became lower. THe heterotrophic bacteria isolated from all of the pH gradient were 12 genera and 22 species, and among them, gram negative and gram positive bacteria were 64% and 36%, respectively. As pH decreased, the distribution rate of gram negative bacteria increased while that of gram positive bacteria decreased. Regarding to distribution rate of genuses in each pH gradient, 13 genuses appeared at pH 7 while only 5 genuses appeared at pH 3, which means that the diversity of genera decrease as pH decreased. The activities of extracellular enzyme showed the ranges of 0.008∼0.292μMl^-1hr^-1 in bioreactor system. The enzymatic activities decreased rapidly below pH 5 and then sustained 5∼38% at the lower pH values.

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].

Interferon-α 및 -γ가 Interleukin-2로 유도된 Lymphokine-activated Killer세포 활성에 미치는 영향

최용(Yong Choi),최영길(Yong-Keel Choi),김정목(Jung-Mogg Kim),정용훈(Yong-Hoon Chung),김경희(Kyung-Hee Kim),한왕수(Wang-Soo Han) 大韓微生物學會 1992 大韓微生物學會誌 Vol.27 No.4

금강수역내에서 분리된 몇 종의 Ampicillin 내성균의 β-Lactamase 발현양상

이기성,고동규,최원창,문영길,박영식,최청일,최영길 ( Ki Sung Lee,Dong Kyu Ko,Won Chang Choi,Yong Keel Mun,Young Sik Park,Chung Il Choi,Yong Keel Choi ) 한국환경생물학회 1994 환경생물 : 환경생물학회지 Vol.12 No.1

In order to characterize the bacterial β-lactamase types occurred in Kum river area, this research was designed to analyze with identification upon ampicillin (Amp) resistant bacteria, and was investigated into relationships between β-lactamase expression (inducibility) and growth phase under ampicillin shift and with restriction patterns of R-plasmids. As the identification result upon 4 strains of Amp resistant bacteria, KL 601 is identified as Pasteurella maltocida, KL 602 as Enterobacter agglomerans, KL 609 as Pseudomonas maltophilia and KL 611 as Acinetobactor calcoaceticus, respectively. In order to investigate Amp effect upon growth, when the Amp resistant bacteria were cultivated in nutrient liquid LB medium, in LB medium added with Amp, or in LB medium in the manner of Amp shift, the changes in growth rate and lag phase could not be observed. However, upon the prototrophic strains, KL 602 and KL 609, examining Amp effect upon these two strains in minimal GM63 liquid media, even though there was no change of maximum growth yield, the latent lag phase become very lengthened. In nutrient medium, β-lactamase activities of these 4 strains were metabolically regulated in accordance with growth phase, on the other hand, in minimal medium were differently regulated in accordance with growth phase and with strains. It could be postulated that KL 609 strain has the M.W.24,000, β-lactamase type which E. coli comprise, however, that KL 601, KL 602 and KL 611 have the M.W.35,000, β-lactamase type which E. cloacae or C. freundii comprise. Through the whole growth phase, since Amp did not affect to phosholipid metabolism, there is no change in phospholipid compisition upon Amp effect. Main phospholipid are the phosphatidyl glycerol and cardiolipin in all 4 Amp resistant strains. So, it was very significant that there were no changes in phospholipid composition and in growth rate upon nutrient medium under Amp stress. In order to recognize whether Amp resistant strains comprise the plasmid or not, preparation of plasmids and restriction digestion with Bam H1 were carried out, KL 601 strain has about 30 Kb of plasmid, KL 609 and KL 611 strain have about 25 Kb of plasmid and KL 602 does not have the plasmid, however. Hence, it will be predicted strongly that β-lactamase gene in KL 602 might be encoded chromosomally. Moreover, considering the results upon the changes of β-lactamase acticity, upon β-lactamase inducibility and upon changes of periplasmic protein profile under Amp stress, its prediction is very recognizable.

부영양화 수역에서의 Cyanophage 의 분리와 동정

김민,최영길,Kim, Min,Choi, Yong-Keel 한국미생물학회 1992 미생물학회지 Vol.30 No.6

경기도 의왕시에 위치한 백운 저수지에서 분리된 cyanobacteria 인 Synechococcus sp. 로부터 한 종의 cyanophage 를 분리하여 ultrafiltration, differential centrifugation 과 sucrose density gradient centrifugation 을 이용하여 정제하였다. 분리된 cynophage 는 transmission electron microscope (TEM) 를 이용하여 100,000 배로 관찰한 결과 직경이 89 nm인 isometric head 와 tail 의 전체 길이가 111 nm 의 contractile tail 을 가진 phage 로서 Myoviridae 에 속함을 알 수 있었다. 생화학적 특징으로는 20~$40^{\circ}C$ 와 pH 5-10에서 50% 이상의 안정성을 유지하며 $30^{\circ}C$ 와 pH 9 에서 최고의 infectivity 를 나타내었다. Synechococcus sp. cyanophage was isolated from Baekwoon reservoir located in KyonggiDo. The cyanophage was purified by employing ultrafiltration. differential centrifugation. and sucrose density gradient centrifugation. Electron microscopic observation indicated that the sizes of its isometric head and contractile tail are 89 nm and] II nm. respectively. which means that the isolated cyanophage is included in the group. Myoviridae. The cyanophage maintained the stability of more than 50 percent from $20^{\circ}C$ to $40^{\circ}C$ and from pH 5 to 8. and had the maximal infectivity at $30^{\circ}C$ and pH 9 implying its ecological significance.

Penicillium oxalicum ( HCLF-34 ) 의 세포외 분비 효소에 의한 Anabaena cylindrica 의 분해

현성희,최영길 ( Soung Hee Hyun,Yong Keel Choi ) 한국환경생물학회 1998 환경생물 : 환경생물학회지 Vol.16 No.2

Penicillium oxalicum (HCLF-34) that showed excellent lytic characters of Anabaena cylindrica, was isolated by author. Algal lytic substance from this fungus was exchanged color of Anabaena cylindrica broth culture from dark green to pale reddish-brown color. After three hours in the mixed culture Anabaena cylindrica with lytic substance, the host was segmented, formed cluster, appeared speroblast and the sheath was lysed on the microscopy. In addition, the cell wall surface of the host was manifested the pore, lysed cell to cell junction region and gushed out cytoplasmic materials after one hour in the mixed culture on transmission electron microscopy.

Synechococcus sp.의 광합성이 Cyanophage 증식에 미치는 영향

김민,최영길,Kim, Min,Choi, Yong-Keel 한국미생물학회 1994 미생물학회지 Vol.32 No.1

Synechococcus sp.의 cyanophage는 early, late viral function 모두 빛을 필요로 하는 것으로 나타났으며 증식 초기 2시간 동안 암처리한 경우 200%의 burst size를 나타내었다. Dark 상태에서의 Synechococcus sp.의 cyanophage증식은 대조군에 비해 11%의 burst size를 나타내었다. 광합성 억제제인 DCMU를 $10^{-6}$M로 처리했을 때 virus yield가 2%로 감소했으며 $10^{-4}$M의 CCCP는 cyanophage의 증식을 거의 중지시켰다. 또한 이러한 숙주세포의 광합성 의존도는 LPP-1, N-1과 AS-1보다는 크나 SM-1보다는 작은 것으로 나타났다. Light appears to be needed in the early and late function of the cyanophage of Synechococcus sp. and dark treatment during the first 2 hr of the replication cycle increased the virus yield to 200%. The burst size of the cyanophage multiplied in Synechococcus sp. in dark was 11% of that of control. The viral multiplication was reduced 2% in the presence of photosynthetic inhibitor, DCMU of $10^{-6}$ M, and nearly blocked in $10^{-4}$ M CCCP. These data suggested that the photosynthetic dependence of the cyanophage is greater than those of LPP-1 and AS-1, and smaller than SM-1.

경기도 5개 저수지에 우점하는 남조류의 순수분리

김민,최영길 ( Min Kim,Yong Keel Choi ) 한국하천호수학회 1992 생태와 환경 Vol.25 No.2

The distribution of algae was investigated at 5 reservoirs located in Kyonggi-Do. Blue-green algae such as Oscillatoria and Microcystis which are pollution indicators and water-bloom causing agents were dominant in the eutrophic waters. In order to develop a method for using cyanophage as biological controller of eutrophication, 7 strains of filamentous cyanobacteria and 1 strains of unicellular blue-green algae were isolated on the BG-11 solid medium added with 50㎍/ml cycloheximide, 50㎍/ml nystatin, and 10㎍/ml germanium dioxide (GeO_2).

Moraxella sp. CK-1 의 세포외 효소에 의한 Anabaena cylindrica 세포벽의 분해

김철호,최영길,민병례 ( Chul Ho Kim,Yong Keel Choi,Byung Re Min ) 한국환경생물학회 1997 환경생물 : 환경생물학회지 Vol.15 No.1

Moraxella sp. CK-1 has been known to inhibit the growth of cyanobacteria including A. cylindrica. This growth inhibition by the bacteria was accomplished through the secretion of lytic enzyme (s) out of the bacterial cells. Extracellular cell wall lytic and proteolytic activity, which began to appear at the early exponential growth phase, changed similarly during the growth of Moraxella sp. CK-1. Extracellular cell wall lytic enzyme showed a temperature optimum of 60~70℃, a temperature stability of up to 60℃, and a pH optimum of 9.0. The lytic activity was enhanced by several enzyme stabilizers, chemicals, and metal ions except Ca^2+ and Mn^2+. Fe^3+ and Cu^2+ ions inhibited the lytic activity almost completely. The lytic enzyme was believed to be amidase or endopeptidase from the result that free amino groups in substrate solution increased when SDS-insoluble peptidoglycan was treated with extracellular enzyme(s) of Moraxella sp. CK-1.