• Archives of Pharmacal Research
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• 제22권1호
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• pp.25-29
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• 1999

Psammaplin A, a natural bromotyrosine derivative from an associated form of two sponges (Poecillastra sp. and jaspis sp.) was found to possess the antimicrobial effect on the Gram-positive bacteria, especially on methicillin-resistant Staphylococcus aureus (MRSA). The minimal inhibitory concentration of psammaplin A against twenty one MRSAs ranged from 0.781 to 6.25 ${\mu}g/ml$, which that of ciprofloxacin was 0.391~3.125${\mu}g/ml$. Psammaplin A could not bind to penicillin binding protein, but inhibited the DNA synthesis and the DNA gyrase activity with the respective 50% (DNA synthesis) and 100% (DNA gyrase) inhibitory concentration 2.83 and 100 ${\mu}g/ml$. These results indicate that psammaplin A has a considerable antibacterial activity, although restricted to a somewhat narrow range of bacteria, probably by inhibiting DNA gyrase.

• 약학회지
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• 제39권2호
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• pp.131-136
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• 1995

Clinically isolated bacterial strains resistant to almost of all the clinically superior .betha.-lactam antibiotics can be used to screen the promising ones among the newly synthesized $\beta$-lactam antibiotics. To select the resistant strains, the susceptibility of 389 strains of S. aureus, 144 strains of coagulase negative staphylococci, 509 strains of E. coli, 115 strains of E. cloacae and 187 strains of P. aeruginosa to methicillin, ampicillin, piperacillin and gentamicin was determined. The susceptibility of 19 bacterial strains selected through the first screening to cefixime, cefotiam, cefotaxime, flomoxef, cepfirome, cefdnir, SCE-2787, panipenem and imipenem was determined. Four strains of S. aureus finally selected have high degree of resistance to almost of all $\beta$-lactam antibiotics used and also produce $\beta$-lactamases. These 4 strains of S. aurues can be used to screen effectively the promising $\beta$-lactam antibiotics among the numerous numbers of the newly synthesized $\beta$-lactam antibiotics.

• The Plant Pathology Journal
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• 제20권3호
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• pp.206-211
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• 2004

Transgenic Nicotiana benthamiana plants harboring coat protein (CP) gene of Zucchini green mottle mosaic virus (ZGMMV) were generated for virus-resistant screening and complementation analysis of related viruses for environmental safety assessment (SA) of living modified organism (LMO) purposes. Transformation of leaf disc of N.benthamiana was performed by using Agrobacterium-mediated method and the pZGC-PPGA748 containing the ZGMMV CP and NPTII genes. Two kinds of transgenic homozygous groups, virus-resistant and virus-susceptible N.benthamiana lines, were obtained by screening of challenging homologous virus for Tl generations. These two pathologically different lines can be useful for host-virus interactions and LMO environmental SA.

• 대한임상검사과학회지
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• 제45권1호
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• pp.1-4
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• 2013

Vancomycin-resistant enterococci (VRE) have emerged as important healthcare-associated infection since last two decades. ChromID VRE agar (cIDVA) is useful for VRE rectal swab screening. We investigated all VRE were isolated on the cIDVA. A total of 363 rectal swabs of 85 patients to test VRE screening were inoculated into bile-esculin (B-E) broth with $6{\mu}g/mL$ vancomycin. After 24 hours incubation, we subcultured B-E broths were changed to black onto cIDVA. All isolates were identified by the MICROSCAN and VITEK2. The vanA gene and vancomycin minimal inhibition concentration (MIC) were detected by PCR and E-test respectively. 277 E. faecium (84.7%), 16 E. faecalis (4.9%), 25 E. avium (7.6%), 8 E. gallinarum (2.4%) and 1 E. raffinosus (0.3%) were isolated. 10.3% of VRE detected on cIDVA were other than E. faecium and E. faecalis that presented various color from colorless to pale violet. All isolates contained vanA and vancomycin MIC were > $256{\mu}g/mL$. VRE isolates other than E. faecium and E. faecalis should be objective to the contact precautions for healthcare-associated infection control if they possess vanA gene. Due to emerging enterococci carrying vanA such as E. avium, E. gallinarum, and E. raffinosus, VRE surveillance should be expanded to all isolates on chromogenic agar.

• 농업과학연구
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• 제48권1호
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• pp.151-161
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• 2021

Fusarium wilt disease of tomato plants caused by Fusarium oxysporum f.sp. lycopersici (FOL race2) is one of the most important diseases of tomatoes worldwide. In the competition between tomato and FOL, the FOL can win by overcoming the immune system of tomato plants. Resistant interaction between the FOL race2 and tomato plants is controlled by avirulence genes (AVR2) in FOL and the corresponding resistance genes (I2) in tomato plants. In this study, 7 FOL isolates (KACC) were used to test their pathogenicity, and FOL race2 was selected because it is a broad problem in Korea. The Fol40044 isolates showed the most severe pathogenicity, and the avr2 gene was also isolated and identified. Moreover, to select resistance, 20 tomato varieties were inoculated with the Fol40044, and the degree of pathogenicity was evaluated by analyzing the expression of the avr2 gene. As a result, three resistant tomato varieties (PCNUF73, PCNUF101, PCNUF113) were selected, and the expression of the avr2 gene was much lower than that of the control Heinz cultivar. This result shows that the screening assay is very efficient when the avr2 gene is used as a marker to evaluate the expression level when selecting varieties resistant to tomato wilt disease. Based on these results, it is possible to isolate the I2 gene, which exhibits resistance and molecular biological interactions with the AVR2 gene from the three tomato-resistant varieties. The I2 gene provides breeders more opportunities for Fusarium disease resistance and may contribute to our understanding of their interactions with the FOL and host plant.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2000년도 춘계 학술대회지
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• pp.50-51
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• 2000

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.938-945
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• 2016

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defense-related genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3345-3349
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• 2013

Hsp90 shows great promise as a therapeutic target due to its potential to disable multiple signaling pathways simultaneously. In this study, we discovered that a natural product, butein moderately inhibited the growth of drug-resistant cancer cells (A2780cis and H1975), and brought about the degradation of oncogenic Hsp90 client proteins. The study demonstrated that butein would be a therapeutic lead to circumvent drug-resistance in cancer chemotherapy. The structure-based screening, synthesis, and biological evaluation of butein are described herein.

• 식물병연구
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• 제21권3호
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• pp.201-207
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• 2015

본 연구는 Fusarium oxysporum f. sp. melonis에 의해 발생하는 멜론 덩굴쪼김병의 간편 대량 저항성 검정법을 확립하기 위하여 수행하였다. 멜론의 덩굴쪼김병 저항성 검정에는 대부분 뿌리 침지(root-dipping) 접종 방법을 사용하고 있지만, 이 방법은 접종과정이 번거로워 노동력과 시간이 많이 소요된다. 간편 저항성 검정법을 개발하기 위해 뿌리 침지, scalpel, tip 및 토양관주 방법으로 F. oxysporum f. sp. melonis 균주를 감수성 및 저항성 멜론 품종에 접종하여 덩굴쪼김병 발생을 조사하였다. 그 결과 멜론 품종들은 scalpel 방법과 tip 방법에서 뿌리 침지 방법에서와 같은 분명한 저항성과 감수성 반응을 보였다. 하지만 tip 방법은 scalpel 방법보다 개체간의 발병도 차이가 약간 더 심하였으며 토양 관주 방법의 경우에는 감수성 멜론 품종들에서 덩굴쪼김병 발생이 매우 낮았다. 따라서 멜론 덩굴쪼김병의 간편 대량 저항성 검정을 위한 효율적인 접종 방법으로 scalpel 방법을 선발하였다. 그리고 scalpel 방법으로 접종할 때 접종 농도($1{\times}10^6$, $1{\times}10^7conidia/ml$)와 접종 후 재배 온도(25, $30^{\circ}C$)에 따른 멜론 품종들의 덩굴쪼김병 발생을 조사한 결과, 이들은 scalpel 방법으로 접종된 멜론 품종의 저항성 정도에 거의 영향을 미치지 않았다. 그리고 확립한 간편 검정법을 이용하여 시판 멜론 22개 품종의 덩굴쪼김병 저항성을 뿌리 침지 접종 방법과 비교하여 실험하여 이 방법의 효용성을 확인하였다. 이와 같은 결과로부터 멜론 덩굴쪼김병에 대한 간편 대량 저항성 검정법으로 멜론 종자를 파종하고 온실($25{\pm}5^{\circ}C$)에서 7일 동안 재배한 유묘의 뿌리를 scalpel을 이용하여 상처를 준 후에 $1{\times}10^6conidia/ml$ 농도의 멜론 덩굴쪼김병균 포자현탁액을 포트 당 10 ml씩 관주하고 $25-30^{\circ}C$에서 약 3주일 동안 재배하는 것을 제안하고자 한다.

• Natural Product Sciences
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• 제6권1호
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• pp.36-39
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• 2000

Acorenone, a diterpene isolated from Acorus gramineus, showed strong resistance inhibitory activity against multi-drug resistant microorganisms such as Staphylococcus aureus SA2, which has resistance to 10 usual antibiotics including chloramphenicol (Cm). At the level of $5\;{\mu}g/ml$ when combined with $50\;{\mu}g/ml$ of Cm. Bacterial resistance to Cm is due to the presence in resistant bacteria of an enzyme, chloramphenicol acetyltransferase (CAT), which catalyses the acetyl-CoA dependent acetylation of the antibiotic at C-3 hydroxyl group. To elucidate the mechanism of resistant inhibitory effect, the acorenone which had the strongest resistant inhibitory activity, was investigated on the CAT assay. As the result, the combination of Cm and acorenone showed the strongest inhibitory activity on CAT as noncompetitive and dose dependent manner.