• 한국식품영양과학회지
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• 제23권6호
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• pp.1014-1019
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• 1994

갓 중의 향균성 물질을 검색할 목적으로 에탄올추출물이 미생물의 증식에 미치는 영향과 전자현미경에 의한 세균의 형태변화를 살펴보았다. 갓 에탄올추출물의 농도별 항균활성은 대부분의 그람 양성균에서는 10mg/ml로 강하게 나타났으며, 그람 음성규느이 경우는 20mg/ml에서 나타났다. 그리고 젖산균 및 효모에서는 40mg/ml로 세균에 비하여 항균력이 약하게 나타났따. 갓 에탄올추출물이 미생물의 대수증식기에 미치는 영향은 E. coli와 S. aureus 두 균주 모두 20mg/ml 이상의 첨가시는 4시간 이후부터 균의 생육이 완전히 억제되었다. 갓 에탄올추출물로 처리한 E. colid와 S. aureus 두 균주를 전자현미경으로 관찰한 결과, 그람 음성균인 E. coli의 경우는 균체표면이 불규칙적으로 수축된 형상을 보였고, 그람 양성균인 S. aureus의 경우는 균체가 팽윤되고 타원형으로 변형되어 두 균주 모두 심한 형태학적인 변화가 있음이 관찰되었다.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.379-384
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• 2010

수집한 전통 장류에서 세포외효소(amylase, protease, cellulase, lipase and fibrinolytic enzyme) 분비능이 우수한 미생물을 분리한 후, 16S rRNA 유전자분석과 생리활성 특성을 조사하였다. amylase와 cellulase 분비능은 모든 선발균주에서 표준균주인 Bacillus subtilis KACC 10114보다 높게 나타났다. Protease 분비능은 D2-14균주를 제외한 모든 선발균주에서 활성이 있었으며, lipase 분비능은 D8-8과 K4-1을 제외한 균주에서 활성이 나타났다. 혈전용해 활성은 D8-2를 제외한 모든 선발균주에서 활성이 나타났으며, D8-8과 K4-1이 가장 높은 활성을 나타냈다. 선발균주인 K3-2, K4-1, K11-1-4, K11-1-6, K11-7, K12-3 와K14-9은 그람 양성세균과 그람 음성세균 그리고 효모에서도 높은 항균활성을 나타내었다. 간장 및 된장에서 분리한 균주들을 동정하기 위해 분자수준에서 16S rRNA 유전자 염기서열을 분석한 결과, 거의 Bacillius sp.로 나타났다. 발효과정에서 세포외효소 분비능과 생리활성이 우수한 미생물을 분리, 확보함으로써 전통 장류의 고급화 및 품질향상과 제조공정의 표준화가 가능할 것으로 여겨진다

• 생명과학회지
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• 제21권12호
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• pp.1710-1715
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• 2011

Nano plasma ion (NPi) generator에서 발생한 NPi의 미생물에 대한 살균 효과를 측정하기 위해 미생물 종류, 조사 시간, 챔버 용적, 이온 수량, 거리에 따라 실험 하였다. 먼저 6종의 미생물 Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis를 대상으로 실험한 결과 미생물 종류에 따라 각각 다른 감소율을 나타냈으며, 그람 음성균인 E. coli가 96.57%로 가장 높았고, 그람 양성균 중 포자를 생성하는 B. subtilis가 57.41%로 가장 낮았다. 그리고 NPi 조사시간에 따라 살균력 측정한 결과, 반응 초기에 대부분의 미생물이 사멸하였으며 이후 서서히 증가하였다. 또한 챔버의 크기에 따른 E. coli의 감소율을 비교하였으며 $0.005m^3$부터 $30m^3$까지 5개 챔버에서 NPi를 2시간 조사한 결과 용적이 증가함에 따라 포화이온 농도는 낮아졌고 이와 함께 살균력도 감소하였다. 이에 $1m^3$ 챔버에 NPi generator를 추가로 설치하여 포화 이온농도에 따른 E. coli의 감소율을 알아보았고 포화 이온 농도가 증가함에 따라 감소율도 함께 증가하는 것으로 나타났다. 마지막으로 NPi generator의 거리에 따른 E. coli의 감소율을 확인하였고 이온이 직접적으로 분출되는 부분의 99.19%를 제외한 나머지 위치에서 팬에 의한 이온 순환으로 포화농도가 비슷하게 유지 되었으며 약 97%의 감소율을 나타냈다.

• Advances in materials Research
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• 제9권3호
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• pp.233-250
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• 2020

In this study, a chitosan based coating method was developed and applied on the shoe lining leather surface for evaluating its inhibition to bacterial and fungal attacks. At first, chitosan was prepared from raw prawn shells and then the prepared chitosan solution was applied onto the leather surface. Secondly, the characterization of the prepared chitosan and chitosan treated leather was performed by solubility test, ATR-FTIR, XRD pattern, SEM and TGA. Evaluation of antimicrobial efficacy of chitosan was assessed against two gram positive, two gram negative bacteria and a reputed fungi by agar diffusion test. The results of this study demonstrated that chitosan took place in both the surface of collagen fibres and inside the collagen matrix of crust leather. The chitosan showed strong antimicrobial activities against all the tested microorganisms and the inhibition increased with increasing percentage of chitosan. Therefore, the prepared chitosan in this study can be an environment friendly biocide, which functions simultaneously against different spoilage bacteria and fungi on the finished leather surface. Thus by using the prepared chitosan in shoe lining leather, the possibility of microbial attack during shoe wearing can be minimized which is one of the important hygienic requirements of footwear.

• Journal of Microbiology and Biotechnology
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• 제33권1호
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• pp.106-113
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• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• International Journal of Oral Biology
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• 제39권4호
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• pp.169-176
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• 2014

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format $O_{(1-6)}XXXXX-NH_2$, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-$NH_2$ (pep-1) and WXXXXN-$NH_2$ (pep-2), and one positioned peptide, RRRWRN-$NH_2$ (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic ${\alpha}$-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

• 한국식품조리과학회지
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• 제31권5호
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• pp.515-523
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• 2015

In the study reported here, the antimicrobial and antioxidant activities of the ethanol leaf extract of Dendropanax morbiferus Lev. from Jeju Island was investigated. Of the 14 strains of 12 species of microorganisms tested, the extract exhibited antimicrobial activity observed against seven Gram-positive bacteria of four species, but not against six Gram-negative bacteria and a yeast strain. Using the disc diffusion method, the diameter of the inhibition zone increased with application of the extract with every strain and the highest growth inhibition was exhibited with Staphylococcus aureus KCTC 1916 at 5 mg/ml. The minimal inhibitory concentration of the extract (MIC) by turbidity was 2.5 mg/ml against Bacillus cereus KACC 12672 and 15 mg/ml when with Enterococcus faecalis KCTC 3206. The minimum bacterial concentration (MBC) values defined as being $${\geq_-}99.9%$$ reduction in viable cells against the tested strains was higher than the MIC values. Time killing curves using the optimum MIC were performed on seven strains incubated for 48 hr. The growth of B. cereus KACC 12672 was detected after 12 hr and no significant growth was found in the others strains after 48 hr (p<0.05). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity of the ethanol leaf extract was similar to that of butylated hydroxyanisole (BHA) at the same concentration. These results indicate that leaf extract of D. morbiferus Lev. can be utilized as a natural preservative and an antioxidant.

• International Journal of Industrial Entomology and Biomaterials
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• 제36권2호
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• pp.25-30
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• 2018

The larvae of Hermetia. illucens have a high probability of coming into contact with microorganisms such as bacteria and fungi. Therefore, the survival of H. illucens is primarily the protection of their own against microbial infection. This effect depends on the development of the innate immune system. Antimicrobial Peptides (AMPs) exhibit antimicrobial activity against other bacterial strains and can provide important data to understand the basis of the innate immunity of H. illucens. In this study, we injected larvae with Enterococcus. faecalis (gram-positive bacteria) and Serratia. marcescens as (gram-negative bacteria) to test the hypothesis that H. illucens is protected from infection by its immune-related gene expression repertoire. To identify the inducible immune-related genes, we performed and cataloged the transcriptomes by RNA-Seq analysis. We compared the transcriptomes of whole larvae and obtained a DNA fragment of 465 bp including the poly (A) tail by RACE as a novel H. illucens immune-related gene against bacteria. A novel target mRNA expression was higher in immunized larvae with E. faecalis and S. marcescens groups than non-immunized group. We expect our study to provide evidence that the global RNA-Seq approach allowed for the identification of a gene of interest which was further analyzed by quantitative RT-PCR, together with genes chosen from the available literature.

• 대한화학회지
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• 제34권2호
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• pp.189-196
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• 1990

아세트아닐리드와 부타노일, 헥사노일, 옥타노일기를 가진 n-acyl chloride류로부터 6-acylbenzofuroxan류를 합성하고, 이들과 히드로퀴논 및 4-아미노페놀을 반응시켜 8-Acyl-2-hydroxyphenazine-5,10-dioxide류와 8-acyl-2-aminophenazine-5,10-dioxide류를 합성하였다. 이들 phenazine dioxide 유도체의 향균성을 희석법에 의하여 최소 발육저지 농도로서 조사하였는데, 그람양성균에서 옥타노일기를 가진 phenazine dioxide 유도체들이 부타노일기나 헥사노일기를 가진 유도체를 보다 항균성이 더 강하였으나, 그람음성균에서는 항균성과 아실기의 탄소수와는 관계가 없다는 것은 알았다. 활성산소($O_2^-$) 생성의 주효소인 xanthine oxidase의 활성을 phenazine dioxide류의 효소활성 저해작용은 아실기의 탄소수가 증가함에 따라 증가하였다.

• 한국식품위생안전성학회지
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• 제15권1호
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• pp.55-59
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• 2000

Bamboo oil의 천연 보존료로서의 가치를 평가하기 위해 합성 보존료인 BHA와 이미 수입되어 사용되고 있는 천연보존료인 tea tree oil을 비교하기 위하여 disc diffusion법과 broth dilution 법으로 S. aureus와 E. coli대한 항균력을 검토한 결과를 요약하면 다음과 같다. 1. Disc diffusion법으로 S. aureus에 대한 항균력을 조사한 결과 BHA>tea tree oil>bamboo oil 순이었고 E. coli에 대한 항균력은 bamboo oil이 가장 강하게 나타났으며 다음은 BHA>tea tree oil순으로 나타났다. 2. Broth dilution법으로 S. aureus와 E. coli모든 시료 6.0$\mu$l/ ml 이상에서 모두 측정되지 않아 모든 시료에서 동일하게 최소억제농도가 6.0$\mu$l/ ml 이상 필요한 것으로 나타났다. 3. Bamboo oil의 이용 개발 시 경제적 조건은 동일한 항균력을 기대할 때 tea tree oil에 비하여 약 20%정도 저렴하여 경제성이 충분히 있는 것으로 나타났다.