• 한국미생물·생명공학회지
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• 제44권1호
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• pp.98-105
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• 2016

강원도를 비롯한 전국에서 발효식품 44점으로부터 유해균에 대한 생육억제 활성이 우수한 고초균주를 분리 및 동정하였으며, 생육억제 활성이 가장 우수하였던 Bacillus amyloliquefaciens MBE1283로 명명된 균주의 유해균에 대한 생육억제 활성, 전분분해 효소활성 및 생육특성을 조사하였다. Escherichia coli O157:H7 KCCM40406을 비롯한 8종류의 유해균에 대한 생육억제 활성을 평가한 결과, 막걸리에서 분리된 B. amyloliquefaciens MBE1283 균주는 다른 B. amyloliquefaciens 균주들에 비해 유의적으로 높은 유해균 생육억제 활성을 나타내었다. B. amyloliquefaciens MBE1283 균주의 ${\alpha}$-amylase 효소활성은 대조구 균주들과 비교하였을 때 현저히 낮았으나 glucoamylase 효소활성은 대조구로 사용한 균주와 유사한 수준이었다. B. amyloliquefaciens MBE1283 균주의 최적 생육온도는 $45^{\circ}C$로서 대조구 균주보다 온도에 대한 내성이 있는 것으로 판단되었으며, 균체 성장에 적합한 최적 배지는 pH 6이었다. 본 연구를 통하여 막걸리로부터 분리된 B. amyloliquefaciens MBE1283 균주는 여러 종류의 유해균에 항균활성을 지니며 높은 온도와 낮은 pH에 대하여 내성을 지닌 것을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제44권2호
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• pp.163-170
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• 2016

전국 각지에서 수집된 발표식품으로부터 젖산균을 분리하고 유해균인 B. cereus, L. monocytogenes, S. Typhimurium, S. aureus 및 S. epidermidis 균주에 대하여 생육 억제효능이 강한 L2167 균주를 선발하고, 16S rDNA 분석법을 이용하여 L. plantarum로 동정하였다. L2167 균주의 단백질 분획물을 제작하여 S. aureus 등 5종의 유해균 배양액에 첨가한 후, 전자현미경으로 관찰하였다. L. plantarum L2167 균주의 균체 단백질 분획물은 유해균의 생육을 억제하였으며, 생육 억제활성은 균체 내부에 함유된 단백질이 유해균의 세포막을 파괴하는 것에서 기인하는 것으로 추정되었다. L. plantarum L2167은 pH 5.5로 조절한 MRS 배지에서 35℃로 배양하였을 때, 가장 우수한 비성장속도를 나타냈으며, 대조구로 사용된 L. plantarum KCTC21004보다 NaCl에 대하여 민감한 특징을 나타내었다. 본 연구를 통하여 선발한 L. plantarum L2167 균주는 추가연구를 통하여 유해균의 생육을 효율적으로 억제할 수 있는 스타터 균주로서 개발될 수 있을 것으로 기대된다.

• Mycobiology
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• 제49권1호
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• pp.69-77
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• 2021

The application of antagonistic fungi for plant protection has attracted considerable interest because they may potentially replace the use of chemical pesticides. Antipathogenic activities confirmed in volatile organic compounds (VOCs) from microorganisms have potential to serve as biocontrol agents against pre- and post-harvest diseases. In the present study, we investigated Galactomyces fungi isolated from rotten leaves and the rhizosphere of cherry tomato (Lycopersicon esculentum var. cerasiforme). VOCs produced by Galactomyces fungi negatively affected the growth of phytopathogenic fungi and the survival of nematodes. Mycelial growths of all nine examined phytopathogenic fungi were inhibited on agar plate, although the inhibition was more intense in Athelia rolfsii JYC2163 and Cladosporium cladosporioides JYC2144 and relatively moderate in Fusarium sp. JYC2145. VOCs also efficiently suppressed the spore germination and mycelial growth of A. rolfsii JYC2163 on tomatoes. The soil nematode Caenorhabditis elegans exhibited higher mortality in 24 h in the presence of VOCs. These results suggest the broad-spectrum activity of Galactomyces fungi against various plant pathogens and the potential to use VOCs from Galactomyces as biocontrol agents.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.666-674
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• 2016

The bacterial strains were screened as potential starters for fermenting low-salt doenjang (a Korean traditional fermented soybean paste) using Korean doenjang based on proteolytic and antipathogenic activities under 6.5-7.5% NaCl conditions. Phylogenetic analysis based on 16S rRNA gene sequences showed that they all belonged to the genus Bacillus. Proteolytic and antipathogenic activities against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Aspergillus flavus, as well as fibrinolytic, amylase, and cellulase activities of the 10 strains were quantitatively evaluated. Of these, strains D2-2, JJ-D34, and D12-5 were selected, based on their activities. The functional, phenotypic, and safety-related characteristics of these three strains were additionally investigated and strains D2-2 and D12-5, which lacked antibiotic resistance, were finally selected. Strains D2-2 and D12-5 produced poly-γ-glutamic acid and showed various enzyme activities, including α-glucosidase and β-glucosidase. Growth properties of strains D2-2 and D12-5 included wide temperature and pH ranges, growth in up to 16% NaCl, and weak anaerobic growth, suggesting that they facilitate low-salt doenjang fermentation. Strains D2-2 and D12-5 were not hemolytic, carried no toxin genes, and did not produce biogenic amines. These results suggest that strains D2-2 and D12-5 can serve as appropriate starter cultures for fermenting low-salt doenjang with high quality and safety.

• 대한화학회지
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• 제57권4호
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• pp.483-488
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• 2013

$CuCl_2$로부터 용액합성법에 의해 CuO를 제조하였다. $CuCl_2$를 용액에 첨가하기 전에 용액내에 anatase형 $TiO_2$ 입자를 분산시켜 CuO가 형성되는 과정에서 $TiO_2$/CuO 결합입자를 합성하였다. 얻어진 $TiO_2$/CuO에 적당량의 글루코스를 가하여 반응시켜 CuO의 일부를 $Cu_2O$로 환원시켰다. 얻어진 시료 $TiO_2/Cu_xO$ (1$TiO_2/Cu_xO$ 복합체는 anatase와는 다르게 가시광선 전 영역에서 흡광이 발생했으며 당연한 결과로 태양광선에서 $TiO_2/Cu_xO$ 복합체의 광촉매 활성은 anatase $TiO_2$에 비하여 매우 뛰어난 것으로 나타났다. 또한 $TiO_2/Cu_xO$ 복합체의 항균성이 대단히 뛰어난 것으로 나타났다.

• KSBB Journal
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• 제26권1호
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• pp.62-68
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• 2011

To isolate Lactic acid bacteria for animals, we have screened from Kim-chi, swine intestine, swine feces, and dairy products by random selection and anti-viral, antipathogenic bacteria test. Among them, CLP-1 shown that inhibitory effect against rotavirus, porcine epidemic diarrhea (PED) virus, Salmonella sp, and E.coli. By examining biological property, API-ZYM and identified Lactobacillus plantarum by 16S rDNAgene sequence. CLP-1 determined resistance to low pH and bile salt. Futhermore, the cell body of CLP-1 adhered to the intestinal epithelium tissue of swine and Caco-2 cell. CLP-1 was examined on cell immune system modulating activity in vitro. The whole cell and cell culture supernatant was increasing of interferon-${\beta}$ activity. And then, CLP-1 increased prevention effect by Salmonella enteritidis infection in SPF chickens. And we determined similar result in pigs.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.571-582
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• 2020

Quorum sensing (QS)-mediated infections cause severe diseases in human beings. The control of infectious diseases by inhibiting QS using antipathogenic drugs is a promising approach as antibiotics are proving inefficient in treating these diseases. Marine fungal (Pestalotiopsis sydowiana PPR) extract was found to possess effective antipathogenic characteristics. The minimum inhibitory concentration (MIC) of the fungal extract against test pathogen Pseudomonas aeruginosa PAO1 was 1,000 ㎍/ml. Sub-MIC concentrations (250 and 500 ㎍/ml) of fungal extract reduced QS-regulated virulence phenotypes such as the production of pyocyanin, chitinase, protease, elastase, and staphylolytic activity in P. aeruginosa PAO1 by 84.15%, 73.15%, 67.37%, 62.37%, and 33.65%, respectively. Moreover, it also reduced the production of exopolysaccharides (74.99%), rhamnolipids (68.01%), and alginate (54.98%), and inhibited the biofilm formation of the bacteria by 90.54%. In silico analysis revealed that the metabolite of P. sydowiana PPR binds to the bacterial QS receptor proteins (LasR and RhlR) similar to their respective natural signaling molecules. Cyclo(-Leu-Pro) (CLP) and 4-Hydroxyphenylacetamide (4-HPA) were identified as potent bioactive compounds among the metabolites of P. sydowiana PPR using in silico approaches. The MIC values of CLP and 4-HPA against P. aeruginosa PAO1 were determined as 250 and 125 ㎍/ml, respectively. All the antivirulence assays were conducted at sub-MIC concentrations of CLP (125 ㎍/ml) and 4-HPA (62.5 ㎍/ml), which resulted in marked reduction in all the investigated virulence factors. This was further supported by gene expression studies. The findings suggest that the metabolites of P. sydowiana PPR can be employed as promising QS inhibitors that target pathogenic bacteria.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1069-1076
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• 2010

A novel laccase from Tricholoma mongolicum was purified by using a procedure that entailed ion-exchange chromatographies on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and FPLC-gel filtration on Superdex 75. The purified enzyme was obtained with a specific activity of 1,480 U/mg-protein and a final yield of 15%. It was found to be a monomeric protein with a molecular mass of 66 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its N-terminal amino acid sequence was GIGPVADLYVGNRIL, similar to some but also different to other mushroom laccases. The optimum pH and temperature for the purified enzyme were pH 2 to pH 3 and $30^{\circ}C$, respectively. It displayed a low $K_m$ toward 2,7-azinobis (3-ethylbenzothiazolone-6-sulfonic acid) diammonium salt (ABTS) and high $k_{cat}/K_m$ values. The purified laccase oxidized a wide range of lignin-related phenols, but exerted maximal activity on ABTS. It was significantly inhibited by $Hg^{2+}$ ions, and remarkably stimulated by $Cu^{2+}$ ions. It inhibited HIV-1 reverse transcriptase and proliferation of hepatoma HepG2 cells and breast cancer MCF7 cells with an $IC_{50}$ of 0.65 ${\mu}M$, 1.4 ${\mu}M$, and 4.2 ${\mu}M$, respectively, indicating that it is also an antipathogenic protein.