• The Korean Journal of Physiology and Pharmacology
• /
• 제1권6호
• /
• pp.699-705
• /
• 1997

Although it is known that neuronal cell death during development occurs by apoptosis, the mechanisms underlying excitatory amino acid-induced neuronal cell death remain poorly understood. In this study we have examined the mechanism by which L-glutamate, an excitatory amino acid neurotransmitter, induces cell death in PC12 cell lines. To characterize cell death, we employed sandwich enzyme-linked immunosorbent assay(ELISA) method for cellular DNA fragmentation, DNA agarose gel electrophoresis and chromatin staining by acridine orange and ethidium bromide after treating the PC12 cells with L-glutamate. L-Glutamate caused dose-dependent cell death with a maximum at 24 hrs after the treatment. These cellular fragmentation was blocked by pretreatment of MK-801, a noncompetitive N-methyl-D-aspartic acid(NMDA) receptor antagonist, and nerve growth factor(NGF). Analysis of DNA integrity from L-glutamate-treated cells revealed cleavage of DNA into regular sized fragments, a biochemical hallmark of apoptosis. The PC12 cells that were induced to die by L-glutamate treatment exhibited classical chromatin condensation under the light microscopy after acridine orange and ethidium bromide staining. These results suggest that apoptosis is one of the key features that are involved in L-glutamate-induced excitotoxic cell death in PC12 cells, and these cell death are mediated by NMDA receptor and depend on NGF.

• 미생물학회지
• /
• 제20권1호
• /
• pp.11-20
• /
• 1982

A study was undertaken to examine the effect of curing agents on the stability, curing and segregation of R plasmid pSL100. And also the stability, transfer frequency, and recombination of its segregants obtained from curing agent treatment were studied. Ethidium bromide, acridine orange, and mitomycin-C were used as curing agent. The results obtained were as follows ; 1. The curing agent ethidium bromide, acridine orange, and mitomycin-C were not effective for curing the multiple antibiotic resistant determinant of pSL100 in Salmonella typhimurium and Escherichia coli. However, they induced plasmid segregation with high frequency in S.typhimuruim LT-2strains. TcApSmCm, TcSmCmKm, TcApCm, TcAp, TcKm, Tc segregants were obtained. 2. The resistant markers of the segregents were transferred to S.typhimurium LT-2 strains with high frequencies whereas they were transferred to E.coli K-12 only with low frequencies. 3. The transconjugants obtained from conjugation between two different S.typhimurium segregants were similar to the phenotype of the original R factor pSL100 and the resistant markers were transferred to the S.typhimurium LT-2 or E.coli strain with equal frequencies, indicating that they are recombinants. 4. The transconjugants obtained from conjugation between pSL100 segrgants and pKM101, or pBR322 possessed the resistant markers of the two parental plasmids and they were transferred to both S.typhimurium and E.coli K-12 strains with the same frequencies and maintained stably, suggesting that they are also recombinants. 5. The recombinant pSL100 could be also obtained in rec A-strains of E.coli, suggesting that the gene function of rec A is required for the recombination of pSL100 segregants in E.coli.

• 한국균학회지
• /
• 제24권2호통권77호
• /
• pp.135-141
• /
• 1996

맛과 향이 탁월하며 항암작용을 지닌 표고버섯 Lentinus edodes의 균사체 균질액에 자외선을 조사하여 돌연변이주를 유도, 선발하였다. 자외선 조사시 생존율은 3분 조사시 2.45%, 10분 조사시 0.024%이었다. 자외선 조사에 의한 돌연변이주 선발율은 0.40%이며, ethidium bromide (EtBr) 농화 법에 의해 glycerol 함유 배지에서 자라지 못하는 균주 34종을 선발하였다. 독립영양형으로 되돌아가는 비율은 $4.81{\times}10^{-4}{\sim}8.46{\times}10^{-4}$이었다. 돌연변이 주의 영양요구성을 검정하여 다양한 amino acid, nucleic acid, vitamin 요구성 균주를 선발하였다. 항진균성 약물의 MIC는 cycloheximide 2.0 ug/ml, p-fluorophenylalanine 1000 ug/ml, benomyl 2000 ug/ml이었다. p-fluorophenylalanine 1000 ug/ml에 내성 균주 5종과 benomyl 1000 ug/ml에 내성인 균주 8종을 선발하였다.

• Journal of Photoscience
• /
• 제11권3호
• /
• pp.133-139
• /
• 2004

The metal-ligand complex, $[Ru(phen)_2(dppz)]^{2+}$ (phen=1,10-phenanthroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuPD), was used as a spectroscopic probe for studying nucleic acid dynamics. The RuPD complex displays a long lifetime and a molecular light switch property upon DNA binding due to shielding of its dppz ligand from water. To show the usefulness of this luminophore (RuPD) for probing nucleic acid dynamics, we compared its intensity and anisotropy decays when intercalated into the $tRNA^{val}$ and pBluescript (pBS) II SK(+) phagemid through a comparison with ethidium bromide (EB), a conventional nucleic acid probe. We used frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The mean lifetime for the $tRNA^{val}$ (<${\tau}$> = 166.5 ns) was much shorter than that for the pBS II SK(+) phagemid (<${\tau}$> = 481.3 ns), suggesting a much more efficient shielding from water by the phagemid. Because of their size difference, the anisotropy decay data showed a much shorter rotational correlation times for the $tRNA^{val}$ (99.9 and 23.6 ns) than for the pBS II SK(+) phagemid (968.7 and 39.5 ns). These results indicate that RuPD can be useful for studying nucleic acid dynamics.

• Journal of Microbiology and Biotechnology
• /
• 제6권2호
• /
• pp.145-146
• /
• 1996

The 2.4-kb cryptic plasmid (pKH8) of multidrug-resistant Staphylococcus aureus SA2 was characterized by complete nucleotide sequencing and homology comparison. pKH8 was found to contain three open reading frames. Protein analysis of pKH8 showed that pKH8 was a multidrug resistance plasmid and mediated resistance to ethidium bromide and quaternary ammonium compounds.

• Archives of Pharmacal Research
• /
• 제11권3호
• /
• pp.218-224
• /
• 1988

The preparation of Clostridium butyricum is used as a normalizing agent for human intestinal flora. When the microbe is simultaneously used with rifampicin, it is inactivated by the antibiotic. To develop rifampicin-resistant mutants, rifampicin-sensitive strain Miyairi II 588 of C. butyricum was treated with nitrosoguanidine (NTG). To ensure stable resistance to rifampicin, we examined whether the resistance was plasmid-mediated or chromosome-mediated. It was found that the resistance of four mutant strains was not mediated by its inherent plasmid, but by the chromosomal mutation. These strains were examined for the susceptibility and resistance to other antituberculosis agents and antibiotics. The results showed that these mutants were resistant to the high concentration of the antituberculosis agents.

• 미생물학회지
• /
• 제23권3호
• /
• pp.184-189
• /
• 1985

L. casei Y1T 9018은 자연적으로, 또는 mutagen처리하여 plasmid DNA 7가 curing 또는 deletion되었으며, 이러한 유천적 결함이 생긴 mutants는 다음과 같은 특성을 나타냈다. 1) 탄소원으로서 lactose가 주어졌을때 mutants의 유산 생성능이 현저히 저하되었다. 2) 탄소원으로서 glucose 맺 galactose 첨가시엔 유산 생성 정도가 정상균주와 큰 차이가 없였다. 3) 5 가시 항생제에 대한 내성 맺 lactose 이외의 당에 대한 발효능 시험 갤고파 정상과 차이가 없었다.

• 미생물학회지
• /
• 제18권3호
• /
• pp.115-122
• /
• 1980

We have demonstrated that both L-histidine as an amino acid factor and dextrin as a carbon source were required for the glucose repression. 1% glucose was sufficient to the glucose repression of aerial mycelium formation in Streptomyces lavendulae and Streptomyces aureofacience. the synthesized medium, KK, which is lack of all orgnic nutrients except dextrin was able to induce glucose repression, but the addition of 0.003% or more L-histidiner recovers the capacity of glucose repression. 0.02% or more histidine was reuqired for glucose repression of aerial mycelium formation in the absence of dextrin. Treatments of $5{\mu}M$ ormore ethidium bromide (EtBr0 gave rise to bald mutants at high frequency in Streptomyces aureofaciens, and it is probable that the gene(s) for the function of aerial mycelium formation is linked to plasmed DNA in this species.

• Journal of Microbiology and Biotechnology
• /
• 제19권8호
• /
• pp.787-791
• /
• 2009

In the course of screening for substances that inhibit etoposide (10 ${\mu}g$/ml)-induced apoptosis in human leukemia U937 cells, fungal strain F000120, which exhibits potent inhibitory activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak $C_{18}$ column chromatography and HPLC, and was identified as heptelidic acid (koningic acid) by spectroscopic methods. This compound inhibited caspase-3 induction in U937 cells with an $IC_{50}$ value of 40 ${\mu}M$ after 8 h of etoposide treatment. Fluorescent dye staining with acridine orange and ethidium bromide showed that heptelidic acid inhibited apoptosis. Furthermore, it was found that DNA fragmentation and caspase-3 activation, the biological hallmarks of apoptosis, were inhibited by the compound in a dose-dependent manner, suggesting that heptelidic acid inhibits etoposide-induced apoptosis via downregulation of caspases.

• 대한미생물학회지
• /
• 제22권1호
• /
• pp.95-99
• /
• 1987

When tetracycline resistancy were cured by ethidium bromide treatment, some of the cured strains lost the tetracycline resistance plasmid while other strains kept the plasmids. Both strains of lost and remained plasmids were digested with restriction endonuclease Hind III and these cleaved plasmids were compared with that of parent strains, two plasmid remained strains showed same cleavage patterns between parent and cured strains, however, one plasmid lost strain showed dissimilarity with parent strain, but in the other one strain, among 4 plasmid lost colonies, 2 showed same but other 2 showed different patterns compared to parent strain. Tetracycline was transfered by conjugation in on set(Staphylococcus aureus donor versus Staphylococcus epidermidis, recipient) with relative high frequency but the other 2 sets showed a low degree of frequency and the other 2 sets exhibited no transfer.