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토양환경에서 transformation 에 의한 유전물질의 전이
이건형 한국미생물학회 1990 微生物과 産業 Vol.16 No.1
현재 전세계적으로 10,000여개 이상의 실험실에서 생물공학적인 연구가 진행중에 있고, 200여개 이상의 회사에서 생물공학을 이용한 제품이 만들어지고 있다.(Saftlas, 1984). 이와같은 제품으로 생물농약(예, 모기억제에 사용되는 Bacillus thuringiensis var. israelensis 등)이라든가 insulin, 성장호르몬, lymphotoxin및 항암제등의 의약품(Saftlas, 1984)과 식물품종개량제(예, 질소 공정의 vector로 사용되는 Agrobacterium tumerfaciens의 Ti Plasmid)(McDanial, 1981 ; Shaw, 1986) 등이 있다. 그러나 최근 미생물 생태분야에서는 이와같이 만들어진 미생물들 (genetically engineered microorganisms : GEMs)이 자연 생태계에 유출되었을때 야기될 가능성이 있는 biohazaed에 대하여 관심이 집중되고 있다. (Curtiss, 1976 ; Sharples, 1983 ; Rissler, 1984). 토양환경에서 GEM이 유전물질을 전달항 수 있는 기작은 크게 conjugation, transduction, transformation 등이 알려지고 있다. 여기서는 주로 토양환경에서 transformation에 의한 유전물질의 전달과정에 대한 최근 연구동향을 간단히 기술하고자 한다.
금강 하구 퇴적토의 이화학적 성질과 종속영양세균의 분포에 관하여
이건형,아영칠,홍순우 한국미생물학회 1986 미생물학회지 Vol.24 No.3
Vertical distribution of heterotrophic bacteria and physico-chemical characteristics were measuted in Kum River estuarine sediments. And interrelationship between heterotrophic bacterka and environmental factors was also studied. The type of sediment of Site 1 was silty clay, and sand at Site 2. Annual pH ranges were between 7.1 and 7.7 in the clay type sediment (Site 1) and 6.9-7.2 in the sand type sediment (Site 2). It was shown that organic matter contents were higher in the clay type sediment than those of sand type sediment. Redox potential values of sediments were decreased rapidly with depth at Site 1, but those of Sete 2 showed vertical fluctuation. Nitrogens(ammonia+amino acid-N, nitrate-N, nitrite-N) and phosphate in the clay type sediment showed higher values than those of sand type sediment. Annual distribution of heterotrophic bacteria were ranged $6.71{\times}10^4$ cells/g dry wt. $-2.50{\times}10^6$ cells/g dry wt. In the clay type sediment and $2.67{\times}10^3$ cells/g dry wt. $-1.94{\times}10^6$ cells/g dry wt. in the sand type sediment. Distribution of proteolytic, lipolytic, and amylolytic bacteria were decreased with the depth and the highest density was found in April and the lowest in January. Bacterial populations in sediments were closely correlated with such environmental factors as pH, redox potential, moisture content, organic matter contents, and inorganic nutrients such as nitrite-N and phosphate-P.
금강 하구 퇴적토에서의 종속영양 세균의 분포에 미치는 환경요인과 계절적 우점속에 관하여
이건형 한국미생물학회 1987 미생물학회지 Vol.25 No.2
Dominant genera of heterotrophic bacteria were investigated seasonally in Kum River estuarine sediments. Numerical taxonomy on the isolated heterotrophic bacteria were carried out according to their morphological, physiological, nutritional and biochemical characters. Heterotrophic bacteria in the depths of 0 to 10 cm of sampled sediments were almost facultative anaerobes, and 77.9% to 86.9% of them were Gram negative rods. Kominant genera among the isolates were Pseudomonas, Flavobacterium, Micrococcus, Cnterobacteria and Vibrio during sampling periods. According to their character analyses by similarity index(S), the isolates were clustered in fourteen groups at clay type sediments (Site 1) and four groups at sand type sediments (Site 2).
이건형 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.3
The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods for detecting small number of fecal pathogens in various environments.
군산 인근 해역에서 종속영양 세균의 분포, 평균체적 및 세포외 효소활성력
이건형,김재원,김정희 한국생태학회 1994 Journal of Ecology and Environment Vol.17 No.1
1991년 11월부터 1992년 8월까지 총 8회에 걸쳐 금강하구에서 고군산군도까지 6개 정점을 대상으로 종속영양 세균의 분포와 평군체적 및 세포와 효소활성을 측정하였다. 해양성 종속영양 세균은 1.0X103~5X105 c.f.u./ml의 범주에서 분포하였으며, 간균이 45~72%를 차지하였다. 또한 구균의 평균체적은 (7.69$pm$0.18)X10-2~(8.18$pm$0.38)X10-2$mu$m3, 간균은 (6.09$pm$0.29)X10-2~(7.72$pm$0.41)X10-2$mu$m3의 범주에서 변화하였다. 세포외 효소활성도를 측정한 결과, glucosidase의 활성은 0~3.49$mu$M/l/hr, chitinase의 활성은 0~1.25$mu$M/l/hr, phosphatase는 0~11.95$mu$M/l/hr, amylase는 0~3.80$mu$M/l/hr의 범주에서 측정되어 세포외 효소활성은 여름철에 높은 값을 보였으며, 측정효소중 phosphatase의 활성이 가장 높았다. 종속영양 세균의 분포와 세포외 효소활성은 수온과 유입되는 유기물의 양과 밀접한 관계가 있었으며, 세균의 체적의 크기는 세포외 효소 활성과는 직접적인 관계가 없었다. Water samples were taken at 6 stations from the mouth of Keum River to Kogunsan Archipelago of West Sea during December, 1991 to August, 1992, to determine the distribution of heterotrophic bacteria, their biovolumes and heterotrophic activities. Heterotrophic marine bacteria ranged from $1.0\;{\times}\;10^3to\;5\;{\times}\;10^5c.f.u.$ /ml. As for morphological distribution measured by epifluorescence microscopy, rod-shaped bacteria were between 45% and 72% of all cells during investigation period. Average biovolume of sampled bacteria ranged from $(7.69\;{\pm}\;0.18)\;{\times}10^{-2}to\;(8.18\;{\pm}\;0.38)\;{\times}\;10^{-2}\;{\mu}m^3$ for coccoid bacteria, and from $(6.09\;{\pm}\;0.29)\;{\times}10^{-2}to\;(7.72\;{\pm}\;0.41)\;{\times}\;10^{-2}\;{\mu}m^3$ for rod-shaped ones. The activities of extracellular enzymes ranged from 0.01 to 2.6 ${\mu}M$ /l /hr for glucosidase, from 0.01 to 2.6 ${\mu}M$ /l /hr for amylase, from 0.01 to 8.86 ${\mu}M$ /I /hr phosphatase and from 0.01 to 0.94 ${\mu}M$ /l /hr for chitinase. Extracellular enzyme activities were higher in summer season than in other sampling periods, and phosphatase showed the highest activity among measured extracellular enzymes. Bacterial distribution and their extracellular enzyme activities were associated with water temperature and organic nutrients, but bacterial cell volumes showed no direct relationship with extracellular enzyme activities.