• Title/Summary/Keyword: UV resistant

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Disinfection Characteristic of Sewage Wastewater Treatment Using Solar Light/TiO2 Film System (태양광/광촉매를 이용한 오폐수 살균특성)

  • Cho Il-Hyoung;Lee Nae-Hyun;An Sang-Woo;Kim Young-Kyu;Lee Seung-Mok
    • Journal of Environmental Science International
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    • v.15 no.7
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    • pp.677-688
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    • 2006
  • Currently, the application of $TiO_2$ photocatalyst has been focused on purification and treatment of wastewater. However, the use of conventional $TiO_2$ slurry photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we studied that solar light/$TiO_2$ film system was designed and developed in order to examine disinfection characteristics of sewage wastewater treatment. The optimum conditions for disinfection such as solar light intensity, characteristic of sewage wastewater, amounts of $TiO_2$ and comparison of solar ligth/$TiO_2$ systems with UV light/$TiO_2$ system was examined. The results are as follows: (1) photocatalytic disinfection process with solar light in the presence of $TiO_2$ film more effectively killed total coliform (TC) than solar light or $TiO_2$ film absorption only. (2) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with remain resistant material. (3) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with the increase of amounts of $TiO_2$. (4) TC survival ratio decreased linearly with increasing UV light intensity. (5) The disinfection effect of solar light/$TiO_2$ slurry system decreased more than UV light/$TiO_2$ film systems. (6) The disinfection reaction followed first-order kinetics. We suggest that solar light instead of using artificial UV light was conducted to investigate the applicability of alternative energy source in the disinfection of TC and the degradation of organic material.

Induction of Prochloraz-Resistant Isolates of Botrytis cinerea in Vitro and Their Biological Properties (Prochloraz에 저항성인 잿빛곰팡이균(Botrytis cinerea)의 유기 및 이들 균의 생물학적 특성)

  • 김병섭;박은우;박정헌;노성환;조광연
    • Korean Journal Plant Pathology
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    • v.12 no.2
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    • pp.226-230
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    • 1996
  • 1994~1995년 사이에 대전, 공주, 논산, 부여와 김해 등지에서 채집한 병든 딸기, 토마토, 오이에서 총 1,504 균주의 잿빛곰팡이병균을 분리하여 10 $\mu\textrm{g}$/ml의 약제를 넣은 PDA 배지에서 배양하면서 약제반응을 조사한 결과, benomyl에 대하여는 1,147(76.3%)균주, procymidone에 대하여는 614(40.8%)균주, prochloraz에 대하여는 189(12.6%)균주가 저항성으로 나타났다. UV 처리 및 약제 배지에서의 누대배양을 통하여 prochloraz저항성 균주를 선발하였는데, 이들의 생육 억제 최소 농도(MIC)는 8 $\mu\textrm{g}$/ml 이상이었고, 감수성균의 MIC는 2 $\mu\textrm{g}$/ml 이하였다. 병원력, 포자 발아율, 균핵형성과 같은 적응력과 관련된 생물학적 특성 비교에서 저항성 균주들은 감수성 균주보다 열등하거나 비슷한 정도로 나타났다.

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Production of L-Ornithine by Citrulline Auxotrophic Mutants of Glutamate-Producing Bacteria

  • CHOI, DAE KEON;WUK SANG RYU;BONG HYUN CHUNG;SOO WAN NAM;YOUNG HOON PARK
    • Journal of Microbiology and Biotechnology
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    • v.2 no.2
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    • pp.102-107
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    • 1992
  • For the purpose of producing L-ornithine by microbial fermentation, mutant strains were developed from glutamate-producing bacteria by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and UV irradiation. Brevibacterium ketoglutamicum BK1046, a L-citrulline auxotroph which is also resistant to arginine hydroxamate (Arghx), was isolated and selected as the best producer of L-ornithine. This strain was capable of producing L-ornithine at a concentration of 24 g/l after 69 hours of cultivation in the 21 jar fermentor. The optimum supplementary level of L-arginine, a substitute for L-citrulline, was found to be about 0.2 g/l in the shake-flask fermentation.

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Correlation between Phylogeny and Zn-Resistance in Methylobacterium Species Isolated from Non-Polluted Soil Environments

  • Kim, Hong-Ik;Kazunori Nakamura;Hiroshi Oyaizu
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2000.10a
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    • pp.118-124
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    • 2000
  • Zn-resistant Methylosobacterium strains were isolated from several non-polluted soil samples collected in all over Japan. Zn-resistant Methylosobacterium strains were predominantly detected in all soil samples and they were also characterized as a UV-tolerant bacteria. The MIC test revealed that the isolates have high zinc resistance in comparison with that of reference Methylosobacterium strains obtained from culture collections. The 16S rDNA-based phylogenetic analysis showed that all strains were divided into two clusters designated as cluster A and cluster B in the present study. All isolates were distributed only in the cluster A. The phylogenetic clustering also well coincided with the differences in the pattern of carbon source utilization.

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A Test to Compare the Water Resistance Sun Protection Factor of General Water, Artificial Seawater, and Natural Seawater of Sunscreen (자외선 차단제의 일반 물, 인공 해수, 자연 해수의 내수성 차단지수를 비교하기 위한 시험)

  • Hyoung Hoon Hwang;Eun Young Kang;Su Yeong Kim;Hui Jeong Jung;Jun Seong Yang;Won Kyu Hong;Hong Suk Kim
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.49 no.4
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    • pp.349-354
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    • 2023
  • Sunscreen is a product that protects against ultraviolet rays by blocking and scattering ultraviolet rays, and has now become a daily necessity beyond cosmetics. Applying sunscreen is a common and easy way to prevent skin damage caused by ultraviolet rays. Due to its significance, the evaluation of sunscreen has evolved since its regulation by the FDA in 1978, progressing to standardized methods established by ISO. Additionally, to assess the loss of sunscreen due to activities such as water exposure or sweating, the Ministry of Food and Drug Safety in Korea and ISO have established protocols for evaluating the water-resistant sun protection factor (SPF). However, existing evaluations of water resistance have been mainly confined to test methods involving plain water, and methods accounting for the impact of seawater during activities like beach leisure, sports, and recreation are yet to be established. Based on the existing guidelines for testing the water-resistant UV protection index, this study compared the water-resistant UV protection index in water, artificial seawater (salt water) and natural seawater (sea water) to evaluate the UV protection index in real-world situations such as marine leisure, sports, and leisure activities. Through these results, we were able to compare the differences between water resistance sun protection index tests in ordinary water, artificial seawater, and natural seawater, and suggest a method for water resistance sun protection index tests using natural seawater.

Isolation of the Regulator Gene Responsible for Overproduction of Catalase A in $H_2O$$_2$-resistant Mutant of Streptomyces coelicolor

  • Hahn, Ji-Sook;Oh, So-Young;Keith F. Chater;Roe, Jung-Hye
    • Journal of Microbiology
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    • v.38 no.1
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    • pp.18-23
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    • 2000
  • Streptomyces coelicolor produces three kinds of catalases to cope with oxidative stress and to allow normal differentiation. Catalase A is the major vegetative catalase which functions in removing hydrogen peroxide generated during the process of aerobic metabolism. To understand the regulatory mechanism of response against oxidative stress, hydrogen peroxide-resistant mutant (HR4O) was isolated from S. coelicolor J1501 following UV mutagenesis. The mutant overproduced catalase A more than 50-fo1d compared with the wild type. The mutation locus catRI was mapped closed to the mthB2 locus by genetic crossings. An ordered cosmid library of S. coelicolor encompassing the mthB2 locus was used to isolate the regulator gene (catR) which represses catalase overproduction when introduced into HR4O. A candidate catR gene was found to encode a Fur-like protein of 138 amino acids (15319 Da).

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Antimicrobial Activity of Methyl Gallate isolated from the Leaves of Glochidion superbum Against Hospital Isolates of Methicillin Resistant Staphylococcus aureus

  • Ahmed, Mohammed Dahiru;Taher, Muhammad;Maimusa, Alhaji Hamusu;Rezali, Mohamad Fazlin;Mahmud, Mohammed Imad Al-deen Mustafa
    • Natural Product Sciences
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    • v.23 no.1
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    • pp.5-8
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    • 2017
  • An antimicrobial compound has been isolated from the leaves of Glochidion superbum. The compound was determined as methyl 3, 4, 5-trihydroxybenzoate (methyl gallate), based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis. The isolated compound exhibited potent antimicrobial activity against three clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) by qualitative agar disc diffusion method and quantitative broth dilution method. Agar disc diffusion was done in a dose-dependent manner for each bacterial isolate at disc potencies of 25, 50, 100, and $150{\mu}g/disc$. The zones of inhibition were on average equal to 12.27, 14.20, 15.43, and 24.17 mm respectively. The inhibition zones were compared with that of vancomycin disc at $30{\mu}g$ as a reference standard. The MIC and MBC values were $50{\mu}g/ml$ and $100{\mu}g/ml$ respectively. The results of anti MRSA activity were analyzed using one-way ANOVA with Turkey's HSD and Duncan test. In conclusion, methyl gallate which was isolated from G. superbum showed the inhibition activity against methicillin resistant S. aureus.

Isolation of a High-Yield Mutant Strain for L-Proline Production and Its Fermentation Conditions

  • Ryu, Wuk-Sang;Jang, Hyung-Wook;Cho, Kyoung-Hee;Chang, Soon-Jae;Ryu, Yeon-Woo;Park, Young-Hoon
    • Journal of Microbiology and Biotechnology
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    • v.9 no.5
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    • pp.613-618
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    • 1999
  • L-Proline-producing mutant strains were developed by exposing L-glutamic acid-producing bacteria to N-metyl-N-nitro-nitrosoguanidine and UV irradiation. A L-histidine auxotroph of Corynebacterium acetoacidophilum RYU3161(KCTC 0616BP), which was resistant to sulfaguanidine and proline analogs (DHP, AZC, TAC), was isolated. The activity of the mutant strain's $\gamma$-glutamyl kinase was 45% higher than that of the parent strain. The optimum level of L-histidine for production of L-proline was 0.16 g/l. In a 5-1 jar fermenter, the mutant strain produced L-proline at a high concentration (35 g/l) level within 48 h of cultivation.

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Sclerotiorin: a Novel Azaphilone with Demonstrated Membrane Targeting and DNA Binding Activity against Methicillin-Resistant Staphylococcus aureus

  • Dasagrandhi, Chakradhar;Pandith, Anup;Imran, Khalid
    • Microbiology and Biotechnology Letters
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    • v.48 no.4
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    • pp.429-438
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    • 2020
  • The emergence of multi-drug resistant, pathogenic methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health and has created a need for novel functional therapeutic agents. In this study, we evaluated the underlying mechanisms of the anti-MRSA effect of an azaphilone pigment, sclerotiorin (SCL) from Penicillium sclerotiorum. The antimicrobial activity of SCL was evaluated using agar disc diffusion, broth microdilution, time-kill assays and biophysical studies. SCL exhibits selective activity against Gram positive bacteria including MRSA (range, MIC = 128-1028 ㎍/ml) and exhibited rapid bactericidal action against MRSA with a > 4 log reduction in colony forming units within three hours of administration. Biophysical studies, using fluorescent probes and laser or electron microscopy, demonstrated a SCL dose-dependent alternation in membrane potential (62.6 ± 5.0.4% inhibition) and integrity (> 95 ± 2.3%), and the release of UV260 absorbing materials within 60 min (up to 3.2 fold increase, p < 0.01) of exposure. Further, SCL localized to the cytoplasm and hydrolyzed plasmid DNA. While in vitro checkerboard studies revealed that SCL potentiated the antimicrobial activity of topical antimicrobials such as polymixin, neomycin, and bacitracin (Fractional Inhibitory Concentration Index range, 0.26-0.37). Taken together these results suggest that SCL targets the membrane and DNA of MRSA to facilitate its anti-MRSA antimicrobial effect.

Standardization of a Mass-Production Technique for Pycnidiospores of Dydymella bryoniae, Gummy Stem Blight Fungus of Cucurbits (박과작물 덩굴마름병 Didymella bryoniae의 병포자 대량 생산 방법의 표준화)

  • 권미경;홍정래;선해정;성기영;조백호;김기청
    • Korean Journal Plant Pathology
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    • v.13 no.2
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    • pp.105-112
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    • 1997
  • Didymella bryoniae, gummy stem blight fungus of cucurbits, has been known not to produce its pycnidium in vitro without irradiation. Various methods for producing pycnidiospores of the fungus as an inoculum have been used. However, those methods have not been verified in terms of efficiency of the productivity, activity and synchronous maturation of the inoculum. Therefore, a pycnidiospore production method in vitro that is highly reliable and reproducible has to be developed to obtain a large amount of inoculum for screening disease resistant varieties or effective fungicides. Here we standardized a mass-production technique for pycnidiospores of D. bryoniae in vitro by comprehensively finding the optimal conditions such as kinds and thickness of cultural medium, growing temperature, and quality and duration of irradiation as well as examining the activity and pathogenicity of the pycnidiospores reproduced. In brief, mycelial colony on the PDA plate was cultured at 26$^{\circ}C$ for 2 days under the darkness, and then the plate was irradiated under the UV light (12 hr/a day) for 2~3 days at the same temperature(26$^{\circ}C$). Two days after UV irradiation, a great number of pycnidia was simultaneously formed. This plate was subjected to darkness again for 4~5 days to mature pycnidiospores. We could obtain a large amount of inoculum that is synchronously matured in a short period of time through the above procedures.

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