• 미생물학회지
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• 제54권4호
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• pp.428-435
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• 2018

본 연구는 담수환경에서 항균활성을 보유한 미생물을 발굴하고, 활성 증진을 위해 배양조건을 최적화하는 것이다. 상주시 중동면 오상저수지에서 시료를 채취하여 38종의 미생물을 순수분리하였다. 16S rRNA 염기서열 분석에 근거하여 Proteobacteria강(22종), Actinobacteria강(7종), Bacteroidetes강(6종), Firmicutes강(3종)으로 구성되어있는 것을 확인하였다. 메티실린내성 황색포도상구군 등 10종의 유해미생물에 대한 항균활성을 보유한 Burkholderia sp. OS17 균주를 선발하였다. 항균활성 증진을 위한 상용배지, 온도, 초기 pH별 생육 및 항균활성 비교실험을 수행하였다. OS17 균주는 YPD 배지, $35^{\circ}C$, pH 6.5로 배양했을 때 가장 활성이 높았다. LB, NB, TSB, R2A 배지와 $20^{\circ}C$, $25^{\circ}C$ 배양했을 때는 생장은 가능하나 항균활성이 전혀 없었다. 이전결과를 바탕으로 YPD 배지, $35^{\circ}C$에서 배양하면서 5 L fermenter를 이용하여 생육, 항균활성, pH 확인을 통해 배양 48시간을 최적 배양시간으로 선정하였다. 항균활성을 보유한 미생물의 배양 최적화는 항균물질 생산에 영향을 미치고, 이는 상업적 응용에 이점으로 작용할 수 있다.

• 한국식품조리과학회지
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• 제25권3호
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• pp.350-356
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• 2009

식용 식물색소자원인 울금 추출물의 항균성실험을 통하여 항균활성을 검색하였고, 실제 식품에의 이용가능성을 살펴보기 위하여, 이를 떡과 국수에 첨가하여 식품 보존효과를 검토하여 다음과 같은 결론을 얻었다. 울금을 건조시켜 분쇄한 후 에탄올로 추출, 농축한 것을 10% 농도로 희석하여 1${\sim}$4 mg/disc 농도가 되게 첨가하여 식품부패 미생물의 증식 억제 효과를 검색한 결과 E. coli와B. subtilis에 대한 항균활성은 disc에 점적한 농도가 증가할수록 항균활성을 나타내는 inhibition zone의 크기가 증가하여 4 mg/disc 농도에서 각각 10, 11 mm의 항균력을나타내었고 S. aureus는 4 mg/disc 농도에서만 8.5 mm의항균력을 나타내었다. 이러한 항균활성을 바탕으로 울금추출물을 첨가식품에의 적용가능성을 살펴보기 위해 0,0.25, 0.50, 0.75, 1.00% 농도로 첨가한 떡과 국수를 제조하여 0, 1, 2, 3, 4일 동안 20$^{\circ}$C에 저장하면서 미생물검사 및 관능검사를 실시하였다. 그 결과, 추출물 첨가 떡과 국수가 대조군에 비해 미생물의 증식이 현저히 적었으며, 첨가량이 많을수록 저장효과가 뛰어나 항균활성을지닌 울금 추출물의 첨가가 식품의 저장성 향상에 기여할 수 있으리라 기대된다. 관능검사결과 떡과 국수 모두울금 추출물 0.50% 첨가군이 가장 선호도가 높게 나타났다. 이상의 결과로 보아 울금 추출물 첨가는 떡과 국수의 기호성을 높이고 저장성을 연장시키는 가능성을 확인하였다.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.423-428
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• 2018

산해박 뿌리 정유 추출물에 대한 장내 미생물 5종(Bifidobacterium bifidum, B. longum, C. perfringens, E. coli 및 L. casei)의 항균활성 및 작은소피참진드기(Haemaphysalis longicornis)의 살비활성을 검정하였다. 산해박 정유는 20.0 mg/disc에서 유해균 2종(C. perfringens 및 E. coli)에 대해 항균활성을 확인하였으나, 작은소피참진드기에는 살비활성을 나타내지 않았다. GC-MS 분석을 통해 얻어진 구성성분 중에 2'-hydroxy-5'-methoxyacetophenone이 유해균 2종에 대해서 10.0 mg/disc에서 각각 12.1 및 12.0 mm의 inhibition zone이 나타난 것을 확인하였다. 이와 같은 결과로 인하여 2'-hydroxy-5'-methoxyacetophenone 유도 화합물들의 구조에 따른 항균활성을 검정하고자 acetophenone 계열 유도체 10종(acetophenone, 2'-hydroxyacetophenone, 4'-hydroxyacetophenone, 2'-methoxyacetophenone, 4'-methoxyacetophenone, 2',4'-dihydroxyacetophenone, 2',5'-dihydroxyacetophenone, 2',4'-dimethoxyacetophenone, 2',5'-dimethoxyacetophenone 및 2'-hydroxy-4'-methoxyacetophenone)과 비교 실험한 결과, methyl group이 포함된 acetophenone 유도화합물에서는 유해균 2종에 대해 항균활성을 나타내었으며, 장내유익균에 대해서는 영향을 미치지 않았다. 그러나 hydroxyl group이 포함된 acetophenone 유도화합물에서는 장내 미생물에 대해 항균 활성이 전혀 나타내지 않았다. 이상의 결과를 통해 산해박 정유와 구성성분 2'-hydroxy-5'-methoxyacetophenone 및 그 유도체는 천연 장내 세균총 개선제로서의 가능성을 제시하였다.

• Journal of Dairy Science and Biotechnology
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• 제34권2호
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• pp.63-68
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• 2016

Rhizomes of Kaempferia parviflora (Zingiberaceae) have been used in traditional Thai medicine for health promotion. In this study, the antibacterial activity of ethanol extract of K. parviflora against Cronobacter spp. and enterohemorrhagic Escherichia coli (EHEC) was investigated using paper disc dilution method. The results revealed that the ethanol extract exhibited antibacterial activity against Cronobacter spp. and EHEC. With an increasing concentration of K. parviflora ethanol extract, larger zones of inhibition of Cronobacter spp. and EHEC strains tested were observed. Therefore, its antibacterial activity suggested that K. parviflora could be used as a natural additive to ascertain food safety of various dairy products.

• 대한치과교정학회지
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• 제47권1호
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• pp.3-10
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• 2017

Objective: Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods: AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results: SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions: Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial.

• 대한약침학회지
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• 제20권1호
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• pp.18-22
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• 2017

Objectives: The current investigation was carried out to determine the cytotoxic and the antimicrobial activities of methanolic extracts of Plumbago zeylanica. Methods: The stems, leaves, and whole plants were air dried and extracted with methanol by using a Soxhlet extractor for 72 hours at $55-60^{\circ}C$. The antimicrobial activities were determined from the zones of inhibition, which were measured by using the agar well diffusion method, and the cytotoxicity assays were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method. Results: The methanolic extracts of the stem and the leaves of Plumbago zeylanica were tested against six bacterial species and nine fungal species, and both extracts showed antimicrobial activity in a dose-dependent manner. The leaf extract of Plumbago zeylanica showed maximum antimicrobial activity against both Staphylococcus aureus sub sp aureus and Fusarium oxysporum. The stem extract was found to be more antimicrobial against the Pseudomonas aeruginosa and the Penicillium expansum species. MTT assays were used to test the cytotoxicity of the whole plant extract in the HCT-116 and the K-562 cell lines, and that extract was shown to have weak cytotoxicity in both cell lines. Conclusion: In the present study, the methanolic stem extracts of Plumbago zeylanica were found to possess remarkable antibacterial activities against many human and agricultural pathogens. The extracts were also found to possess significant antifungal activities, but the antifungal activities were less than the antibacterial activities. Finally, the extracts were found to have weak cytotoxicities in the HCT-116 and the K-562 cell lines.

• 보존과학회지
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• 제36권4호
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• pp.255-263
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• 2020

Paulownia coreana has various advantages as a convenient workability, aesthetic outlook, beautiful patterns, low weight and high strength, and its permeability. P. coreana has been widely used for storage but there are no empirical researches proving its functionality in a field of conservation science until now. In this study, the seasonal and daily temperature and relative humidity control, and microbe and insect repellent activity were evaluated under the controlled and uncontrolled circumstances from 2015 to 2016. The results showed to be mainly excellent in relative humidity control and the buffering effect was good to adjust the average daily relative humidity range from the outside. With respect to the antimicrobial properties of P. coreana, we observed that its water-soluble extract produced visible zones of inhibition against five bacteria. However, it was difficult to predict the antimicrobial and/or insecticidal properties.

• Macromolecular Research
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• 제17권9호
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• pp.688-696
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• 2009

In this study, a new class of polyurethane (PU) nanofibers containing silver (Ag) nanoparticles (NPs) was synthesized by electrospinning. A simple method that did not depending on additional foreign chemicals was used to self synthesize the silver NPs in/on PU nanofibers. The synthesis of silver NPs was carried out by exploiting the reduction ability of N,N-dimethylformamide (DMF), which is used mainly to decompose silver nitrate to silver NPs. Typically, a sol-gel consisting of $AgNO_3$/PU was electrospun and aged for one week. Silver NPs were created in/on PU nanofibers. SEM confirmed the well oriented nanofibers and good dispersion of pure silver NPs. TEM indicated that the Ag NPs were 5 to 20 nm in diameter. XRD demonstrated the good crystalline features of silver metal. The mechanical properties of the nanofiber mats showed improvement with increasing silver NPs content. The fixedness of the silver NPs obtained on PU nanofibers was examined by harsh successive washing of the as-prepared mats using a large amount of water. The results confirmed the good stability of the synthesized nanofiber mats. Two model organisms, E. coli and S. typhimurium, were used to check the antimicrobial influence of these nanofiber mats. Subsequently, antimicrobial tests indicated that the prepared nanofibers have a high bactericidal effect. Accordingly, these results highlight the potential use of these nanofiber mats as antimicrobial agents.

• 한국축산식품학회지
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• 제37권4호
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• pp.502-510
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• 2017

This study investigated bacterial growth-inhibitory effect of 69 therapeutic herbal plants extracts on 9 bacterial strains using a disc diffusion assay. Especially, the antimicrobial activity of Psoraleae semen, which showed different activity on pathogenic Gram-positive and Gram-negative bacteria, was evaluated by MIC (minimal inhibition concentration) and biofilm formation assay. The effect of Psoraleae semen extract on bacterial cell membranes was examined by measurement of protein leakage (optical density at 280 nm) and scanning electron microscope (SEM). No clear zone was formed on discs containing Gram-negative bacteria, but Gram-positive bacteria exhibited clear zones. The MICs of Psoraleae semen extract were $8{\mu}g/mL$ for Streptococcus mutans, and $16{\mu}g/mL$ for Enterococci and Staphylococcus aureus. In addition, biofilm formation was inhibited at concentration $8-16{\mu}g/mL$. Protein leakage values and SEM images revealed that cell membranes of Gram-positive bacteria were impaired following exposure to the extract. Further, the extract inhibited the growth of Listeria monocytogenes in sausages. These results indicate that Psoraleae semen extract could be utilized as a natural antimicrobial agent against Gram-positive bacteria.

• 한국식품영양학회지
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• 제28권5호
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• pp.774-781
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• 2015

The objective of the present study was to determine the total phenol and flavonoid contents and to evaluate the antioxidant potential, of different solvent extracts (ethyl acetate, n-butanol, chloroform, and water) from Robus idaeus in various radical scavenging models (DPPH activity, superoxide dismutase (SOD) activity, reducing power, and nitrite scavenging activity), along with their antimicrobial potential. Measurement of total phenol and flavonoid content of the ethyl acetate extract of R. idaeus was found to be significantly higher than those of the other extracts. The ethyl acetate extract (at a concentration of $1,000{\mu}g/mL$) showed significantly higher reducing power and DPPH radical scavenging activity as compared to the other extracts. Results were dose-dependent. Moreover, the ethyl acetate extract of R. idaeus ($1,000{\mu}g/mL$) showed potent antioxidant efficacy ($85.5{\pm}1.18%$) as evidenced by nitrite scavenging ability at pH 1.2. All solvent extracts of R. idaeus showed lower SOD-like activity (13.72~20.54%). In addition, the antimicrobial activity of all solvent extracts except water extract showed strong inhibition (inhibitory zones in mm) of Staphylococcus aureus ($19.40{\pm}1.00mm$) and Bacillus cereus ($20.50{\pm}0.21mm$) growth. In particular, ethyl acetate extracts (100 mg/mL) showed antimicrobial activity comparable to that of tetracycline (0.01 mg/mL), which was used as a positive control. The results of this study indicate that the ethyl acetate extract of R. idaeus is a natural antioxidant and antimicrobial, with enriched phenols and flavonoids concentration, that has potential in the development of health-enhancing food products.