Salvianolic acid B가 자외선B 조사에 의한 plasmid DNA 절단에 미치는 효과

이평재 대한미용학회 2019 대한미용학회지 Vol.15 No.4

Ultraviolet B (UVB), which is 280-320 nm wavelength light, can induce modification of base and (or) DNA breakage by direct or indirect pathways. Generation of hydroxyl radical is one of the mechanisms by which UVB imparts detrimental effect on DNA. Salvianolic acid B (SalB) is one of the components in Salvia miltiorrhiza and has been reported to have antioxidant, anti-inflammation and anti-wrinkle effects. In the present study, SalB was found to protect the DNA breakage and reduce the 2-deoxy-d-ribose degradation under UVB radiation with H2O2. However, SalB increased the DNA breakage and degradation of 2-deoxy-d-ribose in the presence of Cu2+ ion. These results implied that SalB might have had anti-oxidant or pro-oxidant effect depending on the micro-environment. The current study was carried out with direct UVB radiation to DNA. The roles of SalB in the cell or tissue level still remain to be investigated.

Crystal structure of the nuclease and capping domain of SbcD from Staphylococcus aureus

Lee Jinwook,Jo Inseong,Ahn Jinsook,Hong Seokho,Jeong Soyeon,Kwon Aeran,Ha Nam-Chul 한국미생물학회 2021 The journal of microbiology Vol.59 No.6

The SbcCD complex is an essential component of the DNA double-strand break (DSB) repair system in bacteria. The bacterial SbcCD complex recognizes and cleaves the DNA ends in DSBs by ATP-dependent endo- and exonuclease activities as an early step of the DNA repair process. SbcD consists of nuclease, capping, and helix-loop-helix domains. Here, we present the crystal structure of a SbcD fragment from Staphylococcus aureus, which contained nuclease and capping domains, at a resolution of 2.9 Å. This structure shows a dimeric assembly similar to that of the corresponding domains of SbcD from Escherichia coli. The S. aureus SbcD fragment exhibited endonuclease activities on supercoiled DNA and exonuclease activity on linear and nicked DNA. This study contributes to the understanding of the molecular basis for how bacteria can resist sterilizing treatment, causing DNA damage.

만병초 추출물의 식중독 유발균에 대한 항균효과 및 항산화활성

최무영(Moo-Young Choi),임태진(Tae-Jin Rhim) 한국식품영양과학회 2011 한국식품영양과학회지 Vol.40 No.10

본 연구는 만병초 에탄올추출물의 식중독 유발균에 대한 항균효과 및 항산화 활성을 조사하였다. 추출물의 항균활성은 paper disc 방법으로 조사하였다. 추출물을 10 mg/disc 점적한 후 저해환의 크기를 측정한 결과, 그람양성 3균주 중에서 Bacillus cereus에 대해, 그리고 그람음성 5균주 중에서 Escherichia coli O157:H7에 대한 항균활성이 가장 좋았다. 최소 억제 농도(MIC)는 현재 합성보존료로 이용되고 있는 sorbic acid와 비슷하게 나타났다. 또한, 만병초 추출물이 식중독 유발균의 성장에 미치는 효과를 검정하기 위해 Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium과 Escherichia coli O157:H7의 배양액에 250, 500, 1,000 및 2,000 mg/L 농도로 첨가하여 생육을 조사한 결과, 배양시간 별로 250 mg/L 농도까지는 대조군과 차이가 없었으나, 1,000 mg/L 이상의 농도에서는 균의 증식이 억제되었다. 만병초 추출물의 항산화 효능을 조사하기 위해 DPPH 라디칼 소거활성, ROS 생성 억제 및 supercoiled DNA strand 절단 억제효과를 측정하였다. Pyrogallol의 억제율을 100%로 기준하였을 때, DPPH 라디칼을 50% 억제시키는데 필요한 만병초 추출물의 농도는 양성대조군인 α-tocopherol의 약 절반으로 나타났다. 추출물의 농도가 증가할수록 DCF 형광도는 감소하여 ROS 생성이 농도 의존적으로 억제되고 있음을 알 수 있었다. 추출물의 ROS 생성 억제효과는 양성 대조군인 아스코르빈산에 비해 높게 나타났다. 또한, 만병초 추출물은 peroxyl radical 및 hydroxyl radical로 유발된 supercoiled DNA strand 절단을 억제시켰다. 따라서 본 연구결과는 만병초 추출물이 식중독 유발균에 대하여 우수한 항균작용과 항산화능을 나타내어 만병초가 효과적인 천연 보존료 및 항산화제로서 이용될 수 있음을 시사하고 있다. This study was performed to investigate the antimicrobial effects against food-borne pathogens and anti-oxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The IC50 of the extract for DPPH radical scavenging activity was about half that of α-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

Evidence of DNA Replication Licensing and Paternal DNA Degradation by MCM7 and ORC2 in the Mouse One-cell Embryo

Chang Jin Kim,Tae Hoon Kim,Eun-Woo Lee,Kyung-Bon Lee 대한의생명과학회 2017 Biomedical Science Letters Vol.23 No.4

This study was investigated to test whether paternal DNA that was destined for degradation was properly licensed by testing for the presence of mini-chromosome maintenance protein (MCM) 7 and origin recognition complex (ORC) 2 in the paternal pronuclei. ORC2 is one of the first licensing protein to come on and MCM7 is one of the last licensing protein to come on. Zygotes were prepared by injection of control and treated sperm injection (ICSI). To control for DNA breakage, epididymal spermatozoa were treated with DNase I to fragment the DNA, then injected into oocytes. The presence of MCM7 and ORC2 in the pronuclei of mouse zygotes was tested by immunohistochemistry, just before the onset of DNA synthesis, at 5 h after fertilization, and after DNA synthesis began, at 9 h post fertilization. We found that in all cases, both MCM7 and ORC2 were present in both pronuclei at 5 h after sperm injection, just before DNA synthesis began. This indicates that no matter how extensive the DNA damage, recruitment of licensing proteins to the origins of replication was not inhibited. Sperm DNA fragmentation does not prevent licensing of DNA replication origins. Furthermore, the embryo recognizes DNA that is damaged by nucleases. Our data indicate that the one-cell embryo does harbor a mechanism to prevent the replication of severely damaged DNA from spermatozoa, even though the embryos do not undergo classical apoptosis.

Optimal Conditions of Single Cell Gel Electrophoresis (Comet) Assay to detect DNA single strand breaks in Mouse Lymphoma L5178Y cells

Ryu, Jae-Chun,Kwon, Oh-Seung,Kim, Hyung-Tae Korean Environmental Mutagen Society 2001 한국환경성돌연변이·발암원학회지 Vol.21 No.2

Recently, single cell gel electrophoresis, also known as comet assay, is widely used for the detection and measurement of DNA strand breaks in vitro and in vivo in many toxicological fields such as radiation exposure, human monitoring and toxicity evaluation. As well defined, comet assay is a sensitive, rapid and visual method for the detection of DNA strand breaks in individual cells. Briefly, a small number of damaged cells suspended in a thin agarose gel on a microscope slide were lysed, unwinded, electrophoresed, and stained with a fluorescent DNA binding dye. The electric current pulled the charged DNA from the nucleus such that relaxed and broken DNA fragments migrated further. The resulting images which were subsequently named for their appearance as comets, were measured to determine the extent of DNA damages. However, some variations could be occurred in procedures, laboratories's conditions and kind of cells used. Hence, to overcome and to harmonize these matters in comet assay, International Workshop on Genotoxicity Test Procedure (IWGTP) was held with several topics including comet assay at Washington D.C. on March, 1999. In spite of some consensus in procedures and conditions in IWGTP, there are some problems still remained to be solved. In this respect, we attempted to set the practical optimal conditions in the experimental procedures such as lysis, unwinding, electrophoresis and neutralization conditions and so on. First of all, we determined optimal lysis and unwinding time by using 150 $\mu$M methyl methanesulfonate (MMS) which is usually used concentration. And then, we determined optimal positive control concentrations of benzo(a)pyrene (BaP) and MMS in the presence and absence of S9 metabolic activation system, respectively.

지유 에탄올추출물의 생체외 항산화 활성

임태진 한국자원식물학회 2013 한국자원식물학회지 Vol.26 No.2

The objective of this study was to investigate the antioxidative capacity of ethanol extracts from Sanguisorbae officinalis L. root (Sanguisorbae radix) in vitro. The concentration of Sanguisorbae radix extract at which DPPH radical scavenging activity was inhibited by 50% was 0.33 mg/mL, which was similar to IC50 of α-tocopherol (0.40 mg/mL), as compared to 100% by pyrogallol as a reference. Total antioxidant status was examined by total antioxidant capacity against ABTS radical reactions. Total antioxidant capacities of Sanguisorbae radix extract were significantly (p<0.05) higher than those of α-tocopherol. Superoxide scavenging activities of Sanguisorbae radix extract were significantly (p<0.05) higher than those of catechin. Oxygen radical absorbance capacities of Sanguisorbae radix extract were significantly (p<0.05)higher than those of ascorbic acid. Cupric reducing antioxidant capacities of Sanguisorbae radix extract were significantly (p<0.05) higher than those of α-tocopherol. Sanguisorbae radix extract prevented supercoiled DNA strand breakage induced by hydroxyl radical and peroxyl radical. Total phenolic contents of Sanguisorbae radix extract at concentrations of 0.5 and 5 mg/mL were 0.50 and 3.33 mM gallic acid equivalents, respectively. Sanguisorbae radix extract at concentration of 0.01, 0.1 and 0.5 mg/mL inhibited 0.2 mM tert-butyl hydroperoxide-induced cytotoxicity by 33.8, 79.1 and 96.9%,respectively, in HepG2 cell culture system. Thus, strong antioxidant and cytotoxicity-ihnibiting effects of Sanguisorbae radix extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in total phenolic contents. 본 연구에서는 지유 에탄올추출물의 항산화 효과를 조사하였다. Pyrogallol의 억제율을 100%로 기준하였을 때,DPPH 라디칼을 50% 억제시키는데 필요한 지유 추출물의농도는 0.33 mg/mL으로 α-tocopherol의 IC50(0.40mg/mL)과 유사하게 나타났다. 지유 추출물의 총항산화능은 α-tocopherol에 비해 높게 나타났다. 지유 추출물의superoxide 소거활성은 catechin에 비해 높게 나타났다. 지유 추출물의 peroxyl 라디칼 소거활성은 ascorbic acid에 비해 높게 나타났다. 지유 추출물의 구리이온 환원력은α-tocopherol에 비해 높게 나타났다. 지유 추출물은hydroxyl 라디칼 및 peroxyl 라디칼로 유발된 supercoiledDNA strand의 절단을 억제시켰다. 지유 추출물 0.5 및 5mg/mL의 총페놀 함량은 각각 0.50 및 3.33 mM gallicacid와 동등한 수준이었다. 또한, HepG2 세포주를 이용한세포배양에서 지유 추출물 0.01, 0.1 및 0.5 mg/mL 농도의 첨가는 0.2 mM t-BHP로 유도된 세포독성을 각각33.8, 79.1 및 96.9% 감소시켰다. 따라서, 본 연구 결과들은 지유 추출물의 강력한 항산화 효과와 세포독성 억제효과를 나타내며, 이러한 효능은 적어도 자유라디칼의 산화억제와 높은 총페놀 함량에 기인하는 것으로 사료된다.

소리쟁이 추출물의 항산화 효능

임태진,최무영,박희준 한국자원식물학회 2012 한국자원식물학회지 Vol.25 No.5

The objective of this study was to investigate the antioxidative capacity of ethanol extracts from Rumex crispus L. The concentration of R. crispus L. extract at which DPPH radical scavenging activity was inhibited by 50% was 2.15mg/mL, which was lower than that of α-tocopherol (0.43 mg/mL), as compared to 100% by pyrogallol as a reference. Total antioxidant status was examined by total antioxidant capacity against ABTS radical reactions. Total antioxidant capacities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 0.47 and 2.33 mM Trolox equivalents, respectively,which were higher than those of α-tocopherol. Superoxide scavenging activities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 21.5 and 78.9%, respectively, which were not significantly (p>0.05) different from those of catechin. Oxygen radical absorbance capacities of R. crispus L. extract at concentrations of 20 and 100 μg/mL were 62.5 and 156.4 μM μM Trolox equivalents, respectively, which were lower than those of ascorbic acid. Cupric reducing antioxidant capacities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 0.28 and 1.88 mM Trolox equivalents, which were similar or significantly (p<0.05) higher than those of α-tocopherol, respectively. R. crispus L. extract prevented supercoiled DNA strand breakage induced by hydroxyl radical and peroxyl radical. Total phenolic contents of R. crispus L. extract at concentrations of 0.5 and 5 mg/mL were 0.58 and 3.85 mM gallic acid equivalents, respectively. R. crispus L. extract at concentration of 0.1 and 0.5 mg/mL inhibited 0.2 mM tert-butyl hydroperoxide-induced cytotoxicity by 38.5 and 63.5%, respectively, in HepG2 cell culture system. Thus, strong antioxidant and cytotoxicity-inhibiting effects of R. crispus L. extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in total phenolic contents. 본 연구에서는 소리쟁이 에탄올추출물의 항산화 효과를조사하였다. Pyrogallol의 억제율을 100%로 기준하였을 때,DPPH 라디칼을 50% 억제시키는데 필요한 소리쟁이 추출물의 농도는 2.15 mg/mL으로 α-tocopherol의 IC50(0.43mg/mL)에 비해 높게 나타났다. 총항산화능은 ABTS 라디칼에 대한 소거활성으로 측정하였다. 소리쟁이 추출물 0.1및 1 mg/mL의 총항산화능은 각각 0.47 및 2.33 mM Trolox와 동등한 수준이었으며, α-tocopherol에 비해 높게나타났다. 소리쟁이 추출물 0.1 및 1 mg/mL의 superoxide 소거활성은 각각 21.5 및 78.9%이었으며, catechin에 비해 차이가 없었다. 소리쟁이 추출물 20 및 100 μg/mL의peroxyl 라디칼 소거활성은 각각 62.5 및 156.4 μM Trolox와 동등한 수준이었으며, ascorbic acid에 비해 낮게 나타났다. 소리쟁이 추출물 0.1 및 1 mg/mL의 구리이온 환원력은 각각 0.28 및 1.88 mM Trolox와 동등한 수준이었으며, α-tocopherol에 비해 유사하거나 높게 나타났다. 소리쟁이 추출물은 hydroxyl 라디칼 및 peroxyl 라디칼로 유발된 supercoiled DNA strand 절단을 억제시켰다. 소리쟁이 추출물 0.5 및 5 mg/mL의 총페놀 함량은 각각 0.58 및 3.85 mM gallic acid와 동등한 수준으로 높게나타났다. 또한, HepG2 세포주를 이용한 세포배양에서 소리쟁이 추출물 0.1 및 0.5 mg/mL 농도의 첨가는 0.2 mM tert-butyl hydroperoxide로 유도된 세포독성을 각각 38.5및 63.5% 감소시켰다. 따라서, 본 연구 결과들은 소리쟁이추출물의 강력한 항산화 효과와 세포독성 억제 효과를 나타내며, 이러한 효능은 적어도 자유라디칼의 산화 억제와높은 총페놀 함량에 기인하는 것으로 사료된다.