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B . subtilis 형질전환에 미치는 Intercalating agent 의 효과에 관한 연구
임평옥,이희명 한국유전학회 1984 Genes & Genomics Vol.6 No.3
Effects of intercalating agents on transformation in Bacillus subtilis have been investigated. The concentrations of intercalating agents which inhibit the transformation but do not affect significantly the total viable cell numbers were 5㎍/㎖, 10㎍/㎖, and 5㎍/㎖, for ethidium bromide, proflavin, and actinomycin D, respectively. The .effect of inhibition on transformation by the intercalating agents decreased as the treatments delayed. The treatments done 20 minutes after the DNA uptake and thereafter were ineffective in inhibition of transformation. The intercalating agents were considerably more effective in inhibiting the yield of transformants when they were added subsequent to the DNA uptake than prior to the uptake. A probable cause of the inhibitions was investigated by using the donor DNA labeled with ^3H-thymidine. The DNA molecules reisolated from the ethidium bromide-treated bacteria and those from the untreated bacteria showed basically similar radioactivity. Thus, the intercalating agents seemed somehow to interfere with the recombination, such as abnormal pairing, resulting in very poor transforming activity.
Potential Therapeutics Against Flaviviruses
임평옥,이태희,정경민 대한미생물학회 2012 Journal of Bacteriology and Virology Vol.42 No.2
Flaviviruses have been important human pathogens after emerging and resurging flavivirus diseases over the past decades. Although effective therapeutic agents are not yet commercially available for use in humans, significant progress has been made toward developing effective therapeutics and treatments. Several studies have shown that antibodies against the flaviviral E and NS1 proteins play a central role in prophylaxis and/or treatment of flavivirus infection through passive immunization. In addition, many anti-flavivirals, including interferons, oligonucleotide-based platforms, and small compounds, have been developed and evaluated for their antiviral effects. This review provides an overview of various approaches to the development of anti-flaviviral candidates and new insights that could improve our strategies for designing effective therapeutics against flaviviruses.
Paenibacillus sp. DG-22에서의 β-xylosidase 생합성 조절
이태형,임평옥,이용억,Lee, Tae-Hyeong,Lim, Pyung-Ok,Lee, Yong-Eok 한국생명과학회 2007 생명과학회지 Vol.17 No.3
효소생산을 최적화하기 위해서 Paenibacillus sp. DG-22에서의 ${\beta}-xylosidase$ 생합성 조절을 연구하였다. Paenibacillus sp. DG-22의 ${\beta}-xylosidase$는 배양액에 존재하는 탄소원에 의해 조절되는 것으로 관찰되었다. ${\beta}-Xylosidase$의 합성은 xylan과 methyl ${\beta}-D-xylopyranoside$ (${\beta}MeXyl$)에 의해 유도되었으나 쉽게 대사되는 단당류에 의해서는 약간 억제되었다. ${\beta}MeXyl$가 ${\beta}-xylosidase$의 유도를 위한 최적의 기질임을 확인하였고 가장 효과적인 유도는 10 mg/ml의 농도에서 얻어졌다. ${\beta}-Xylosidase$의 생산은 세포의 생장과 연관된 양상을 나타내었으며, 대수기 말에 최대양이 형성되었다. Glucose와 xylose가 존재하면 ${\beta}-xylosidase$의 활성 수준이 감소하는 것으로 보아 이 효소의 생합성은 catabolite repression을 받는것으로 보인다. SDS-PAGE와 활성염색 기술을 이용하여 ${\beta}Mexyl$가 이 효소의 생합성을 유도하며 약 80 kDa 크기의 하나의 ${\beta}-xylosidase$가 존재함을 알 수 있었다. Regulation of ${\beta}-xylosidase$ synthesis in Paenibacillus sp. DC-22 was studied to optimize the enzyme production. ${\beta}-Xylosidase$ synthesis of the Paenibacillus sp. DG-22 was observed to be regulated by carbon sources present in culture media. The synthesis of ${\beta}-xylosidase$ was induced by xylan and methyl ${\beta}-D-xylopyranoside$ (${\beta}MeXyl$) but slightly repressed by readily metabolizable monosaccharides. ${\beta}MeXyl$ was found to be the best substrate for the induction of ${\beta}$-xylosidase and the most effective induction was obtained at a concentration of 10 mg/ml. ${\beta}-Xylosidase$ production showed a cell growth associated profile with the maximum amount formed during the late exponential phase of growth. The presence of glucose and xylose decreased the level of ${\beta}-xylosidase$ activity indicating that its production was subjected to a form of carbon catabolite repression. SDS-PAGE and zymogram techniques demonstrated the induction by ${\beta}MeXyl$ and revealed the presence of one ${\beta}-xylosidase$ of approximately 80 kDa.
Some Effects of Intercalating Agents on Transformation in B . Subtilis
이희명,임평옥 한국유전학회 1984 Genes & Genomics Vol.6 No.3
Some effects of DNA-intercalating agents (Ethidium bromide, Proflavin, and Actinomycin D) on transformation in B. subtilis have been investigated. Competence of recipients can be induced or repressed by decreasing or increasing the temperature of incubation from 42℃ to 37℃ or vice versa. The transformability of the recipients incubated at 37℃ was several hundred fold higher than at 42℃. Induced competence was maintained for about 3 hours. The transformation frequency was higher when Mg^(++) concentration was increased, but it was independent with Ca^(++) concentration. EDTA, an ion-chelating agent, drastically inhibited the transformation. The appearance of transformants in the pancreatic DNase-interrupted transformation showed a lag of about 5 minutes. The concentration of intercalating agents, which inhibits the transformation but does not affect significantly the total viable cell numbers, was 5 ㎍/㎖, 10 ㎍/㎖, and 5 ㎍/㎖, for ethidium bromide, proflavin, and actinomycin D, respectively. The bacterial cells were treated with the intercalating agents a different times after the DNA uptake. The effect of inhibition on transformation by the intercalating agents was found to be an inverse linear response during the first 20 minutes. The treatments applied for 20 minutes after the uptake of DNA were ineffective. The inhibition of transformation was dependent upon the length of exposure to intercalating agents, and the maximum effect was attained at about 20 minutes. Ethidium bromide was considerably more effective in inhibiting the yield of transformants when it was added subsequent to the DNA uptake than prior to the uptake. A probable cause of the inhibition was investigated by using the tritiated donor DNA. The DNA molecules reisolated from the ethidium bromide-treated bacteria and those from the untreated bacteria showed basically similar radioactivity. Thus, the intercalating agents seem somehow to interfere with the recombination, such as by abnormal pairing, resulting in very poor transforming activity.