• Asian-Australasian Journal of Animal Sciences
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• 제30권4호
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• pp.576-584
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• 2017

Objective: To generate recombinant Bacillus subtilis (B. subtilis) engineered for expression of porcine ${\beta}-defensin-2$ (pBD-2) and cecropin P1 (CP1) fusion antimicrobial peptide and investigate their anti-bacterial activity in vitro and their growth-promoting and disease resisting activity in vivo. Methods: The pBD-2 and CP1 fused gene was synthesized using the main codons of B. subtilis and inserted into plasmid pMK4 vector to construct their expression vector. The fusion peptide-expressing B. subtilis was constructed by transformation with the vector. The expressed fusion peptide was detected with Western blot. The antimicrobial activity of the expressed fusion peptide and the recovered pBD-2 and CP1 by enterokinase digestion in vitro was analyzed by the bacterial growth-inhibitory activity assay. To analyze the engineered B. subtilis on growth promotion and disease resistance, the weaned piglets were fed with basic diet supplemented with the recombinant B. subtilis. Then the piglets were challenged by enteropathogenic Escherichia coli (E. coli). The weight gain and diarrhea incidence of piglets were measured after challenge. Results: The recombinant B. subtilis engineered for expression of pBD-2/CP1 fusion peptide was successfully constructed using the main codons of the B. subtilis. Both expressed pBD-2/CP1 fusion peptide and their individual peptides recovered from parental fusion peptide by enterokinase digestion possessed the antimicrobial activities to a variety of the bacteria, including gram-negative bacteria (E. coli, Salmonella typhimurium, and Haemophilus parasuis) and grampositive bacteria (Staphylococcus aureus). Supplementing the engineered B. subtilis to the pig feed could significantly promote the piglet growth and reduced diarrhea incidence of the piglets. Conclusion: The generated B. subtilis strain can efficiently express pBD-2/CP1 fusion antimicrobial peptide, the recovered pBD-2 and CP1 peptides possess potent antimicrobial activities to a variety of bacterial species in vitro. Supplementation of the engineered B. subtilis in pig feed obviously promote piglet growth and resistance to the colibacillosis.

• 한국미생물·생명공학회지
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• 제41권4호
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• pp.442-448
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• 2013

김치, 막걸리 및 시판되는 누룩으로부터 젖산균을 분리한 후 다양한 농도의 알코올을 함유한 MRS 배지에서 배양하여 생육 여부를 조사하였다. 알코올이 13%(v/v) 포함된 MRS 배지에서 $OD_{600}$ 값이 가장 높이 증가한 젖산균 2종을 최종 선별하였고 이 두 균주의 16S rRNA 유전자 염기서열분석 및 API kit를 이용한 생화학적 동정을 실시한 결과 두 종 모두 P. acidilactici에 가까운 종인 것을 확인하여 P. acidilactici K3와 P. acidilactici S1으로 명명하였다. 선별한 P. acidilactici K3와 S1의 bacteriocin 생성 여부를 확인한 결과 식중독균인 S. aureus의 생육 저해를 일으키는 bacteriocin 생성 능력이 있음을 확인하였다. 선별한 두 균주와 표준 균주(P. acidilactici DSM 20284)의 알코올 내성을 비교한 결과 6% 이하의 저농도 알코올이 포함된 배지에서는 균주 생육에 큰 차이가 없었으나 12% 이상의 알코올이 포함된 배지에서는 표준 균주보다 최대 3배 이상 알코올 내성이 뛰어남을 확인하였다. 알코올 내성 균주 P. acidilactici K3와 S1을 살균 막걸리에 첨가한 후 냉장 온도($4^{\circ}C$와 $10^{\circ}C$)에서 저장하며 생균수를 측정한 결과 사멸하지 않고 한 달 간 생균수가 유지됨을 확인하였다.

• 한국축산식품학회지
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• 제35권1호
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• pp.143-148
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• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• 한국식품위생안전성학회지
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• 제27권1호
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• pp.24-29
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• 2012

본 연구에서는 2011년 3월에서 11월 사이에 서울지역에서 유통된 신선 채소류 187건을 대상으로 일반미생물과 식중독균 오염실태를 조사하였다. 중온균은 2.5-9.4 log CFU/g의 범위로 검출되었으며, 세균수가 6 log CFU/g 이상인 시료는 모두 115건(61.5%)으로 나타났고, 가장 균수가 높은 시료군은 미나리였다. 호냉성균은 중온균과 유사한 패턴으로 검출되었으며 범위는 2.3-8.9 log CFU/g로 나타났다. 총대장균군은 시료의 90.9%에서 검출되었으며, 평균함량은 3.2 log CFU/g 이었다. 대장균은 24건(12.8%)에서 검출되었으며, 상추, 미나리, 쑥갓에서 각각 19.1, 16.7, 13.3% 검출되었다. $C.$ $perfringens$는 20건(10.7%), $S.$ $aureus$는 15건(8.0%)이 검출되었으며, $Salmonella$ spp.는 5건(2.7%)이 검출되었다. $L.$ $monocytogenes$는 과일류(토마토)에서 1건이 검출되었으며, $E.$ $coli$ O157:H7은 검출되지 않았다. 식중독 세균과 대장균이 중복해서 검출된 경우는 8건(4.3%)이었다.

• 한국수산과학회지
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• 제38권6호
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• pp.359-364
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• 2005

The distributions of sanitary indicative bacteria and pathogenic bacteria in seawater and four species of farmed fishes, including oliver flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major) and sea bass (Lateolabrax japonicus), collected at fish farms located in the southern coastal area of Korea were investigated from May to October in 2004. The detection rates of fecal coliform and Entirococcus spp. of sanitary indicative bacteria in all samples were $38.9\%$ and $23.8\%$, respectively. The occurrence of fecal coliform was highest of $58.3\%$ in Busan, Geoje and Wando area, followed Yeosu $33.3\%$, Jeju $12.5\%$, Tongyeong $11.1\%$. The occurrence of Enterococcus spp. was highest In Wando area ($45.8\%$), followed by Yeosu ($33.3\%$), Tongyeong ($22.2\%$), Busan ($16.7\%$), Geoje and Jeju ($12.5\%$). The detection rate of fecal coliform was higher than that of Enterococcus spp., except in the Tongyeong area. There was no difference in the detection rate of fecal coliform from May to October, but the detection rate of Enterococcus spp. increased with seasonal warming seawater temperature. Among the pathogenic bacteria, the detection rate of Vibrio alginolyticus ($49.2\%$) in all samples was highest, followed by V. parahaemolyticus ($36.5\%$), Staphylococcus aureus ($6.3\%$), Salmonella sp. ($2.4\%$). However, V cholerae, V. vulnificus and Shigella sp. were not detected in all tested samples. The detection rates of V. parahaemolyticus and V. alginolyticus increased with seasonal warming seawater temperature from May to August.

• 미생물학회지
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• 제46권2호
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• pp.127-133
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• 2010

본 연구는 신생아 태변에서 분리된 Lactococcus lactis HK-9의 다양한 생리적 특성과 항균활성을 조사하기 위하여 실시하였다. 균주 HK-9을 MRS 배지에서 배양하였고, 형태 및 생리학적 특성에 대하여 조사하였으며, BIOLOG 시험과 16SrRNA 염기서열 분석을 통해 균주를 동정하였다. 그 결과 Lactococcus lactis으로 동정되었고, L. lactis HK-9로 명명하였으며, 이 균주의 계통수 분석을 통해 GenBank에 [GU936712]로 등록하였다. 배양기간에 따른 L. lactis HK-9의 생장과 중간 대사산물로서 lactic acid와 acetic acid의 생산 및 pH의 변화를 조사하였으며, 이들 유기산의 생성은 HPLC를 통하여 확인하였다. 유기산의 생성은 L. lactis HK-9의 생장에 따라 증가하는 것을 확인하였으며, 배양 60시간이 지난 후 생성된 lactic acid와 acetic acid의 농도는 각각 495.6 mM, 104.3 mM이었다. 배양 초기의 pH는 7.0이었으며 배양 기간 동안 4.1로 감소하였다. 다양한 그람양성 세균과 그람음성 세균을 대상으로 농축된 HK-9 배양상등액의 항균력을 조사하였으며, 그 결과 항균범위가 그람양성 세균에서만 나타나는 것이 관찰되었다. 농축된 배양상등액을 protease를 처리한 후 항균활성은 소멸하였으며, 상등액의 박테리오신 추정 분자의 분자량은 tricine-SDS-PAGE를 통하여 약 4 kDa으로 확인되었다.

• 한국식품과학회지
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• 제33권6호
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• pp.774-783
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• 2001

식중독 미생물의 효과적인 제어를 위해 인공합성 보존제보다 더 우수한 대체물을 천연 식물체에서 찾고, 이러한 물질들을 효과적으로 이용할 수 있는 방안을 마련하기 위해 식용 혹은 한약재로 이용하는 식물 77 종을 수집하여 부위 별로 75% 에탄올로 추출하여 그 추출물에 대한 항균활성을 실험하였다. 실험한 결과 1,000ppm 수준에서 Listeria monocytogenes 5 균주 모두에 대하여 증식억제효과를 보인 식물은 감송향, 사인, 진득찰, 천황련, 침향, 큰까치수영, 호프 등이었다. 큰까치수영 에탄올 추출물의 L. monocytogenes 5 균주에 대한 최소증식저해농도는 $100{\sim}500\;ppm$이었다. 순차 용매분획물의 항균활성은 헥산 분획물과 클로로포름 분획물의 최소증식저해농도가 $50{\sim}100\;ppm$으로 같았으며, 큰까치수영의 항균물질은 극성이 비교적 낮은 물질임을 알 수 있었다. 큰까치수영의 식중독 미생물에 대한 항균 스펙트럼을 살펴보면 V. parahaemolyticus에 대해서는 실험최저 농도인 25 ppm에서도 72시간까지 완전 증식억제 효과를 나타내었으며, B. cereus에 대해서는 50 ppm, S. aureus에 대해서는 500 ppm 첨가시 72시간까지 완전 증식억제 효과를 나타내었고, S. typhimurium와 S. enteritidis의 경우 대조구에 비하여 균증식이 억제되었으나 농도별 균증식 억제 정도는 큰 차이가 없었다. E. coli의 경우 500 ppm 첨가시 12시간까지 증식한 균이 더 이상 증식하지 않고 72시간까지 그 수준을 유지하는 것으로 보아 큰까치수영 헥산 분획물은 E. coli에 대해서는 정균효과를 나타내는 것으로 판단된다.

• 한국식품과학회지
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• 제36권5호
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• pp.790-794
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• 2004

본 연구에서는 유아용 생균제 개발을 위하여 1세 미만의 한국인 유아로부터 Bifidobacterium균을 분리 및 동정하여 생균제 특성이 우수한 균주를 선발하고자 하였다. 20명의 충북지역 유아 분변으로부터 선택배지를 이용한 plate법, 그람염색법을 이용하여 42종의 Bifidobacterium균을 분리하였고, F6PPK test, MIDI 및 PCR 방법을 통해 최종 7종의 Bifidobacterium균을 동정하였다. 동정된 7종의 Bifidobacterium균의 내산성 및 내담즙성 실험을 통하여 높은 효능을 나타내는 B. psedocatenulatum PBH-29와 B. bifidum PBH-30을 선발하였다. 그리고 병원성균 성장억제 실험에서 B. bifidum PBH-30이 Sal. typhimurium과 Staph. aureus에 대하여 B. psedocatenulatum PBH-29보다 효과적인 저해를 유도하였고, 10% skim milk에서도 48시간 동안 배양한 결과, B. bifidum PBH-30이 B. psedocatenulatum PBH-29보다 좀 더 높은 성장능을 나타냈다. 따라서 본 연구에서는 최종적으로 B. bifidum PBH-30을 유아용 생균제 개발을 위한 균주로 선발하였다.

• Tuberculosis and Respiratory Diseases
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• 제80권4호
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• pp.358-367
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• 2017

Background: Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods: Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results: A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ${\geq}16years$, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion: The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia.

• Advances in Traditional Medicine
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• 제3권3호
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• pp.157-162
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• 2003

Various extracts of higher plants have been used in traditional medicine systems for centuries. While tropical and sub-tropical plants have received considerable attention from the researchers for evaluation of their bioactivity, temeperate plants have always been neglected somewhat. Similarly, seeds of the plants have not been considered seriously compared to other plant parts, e.g. leaves, stems, roots, flowers, etc. as a potential source for biologically active compounds. As part of our on-going evaluation of the extracts of the seeds of temperate plants, especially from Scotland, for biological activity, Achillea millefolium, Angelica sylvestris and Phleum pratense have been chosen for the present study. Both A. millefolium and A. sylvestris are well known for their traditional medicinal uses in Europe and also in the orient, but there is no report on any medicinal properties of P. pratense available to date. Extracts of the seeds of these plants have been assessed for their antioxidant and antibacterial potential and also for general toxicity. Both DCM and MeOH extracts of A. millefolium showed the most significant broad spectrum antibacterial activity among the three plants and inhibited the growth of almost all test strains of bacteria. The DCM extracts of all three species were active against methicillin resistant Staphylococcus aureus (MRSA) and Citrobacter freundii $(MIC=6.25{\times}10^{-1}\;mg/mL)$. While the MeOH extracts of A. millefolium and P. pratense were active against C. freundii, that of P. pratense was also active against MRSA. The MeOH extract of A. sylvestris did not show any antibacterial activity against any of the eight bacterial strains at test concentrations. The MeOH extract of P. pratense showed the most prominent antioxidant activity $(IC_{50}=145\;{\mu}g/ml)$ and there was no antioxidant activity observed with the DCM extract of A. millefolium. The DCM extract of P. pratense was the most toxic $(LC_{50}=20\;{\mu}g/ml)$ among the extracts.