• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.909-915
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• 2017

Bifidobacterium bifidum BGN4 (BGN4) has many proven beneficial effects, including antiallergy and anticancer properties. It has been commercialized and used in several probiotic products, and thus strain-specific identification of this strain is very valuable for further strain-dependent physiological study. For this purpose, we developed novel multiplex polymerase chain reaction (PCR) primer sets for strain-specific detection of BGN4 in commercial products and fecal samples of animal models. The primer set was tested on seven strains of B. bifidum and 75 strains of the other Bifidobacterium species. The BGN4-specific regions were derived using megaBLAST against genome sequences of various B. bifidum databases and four sets of primers were designed. As a result, only BGN4 produced four PCR products simultaneously whereas the other strains did not. The PCR detection limit using BGN4-specific primer sets was $2.8{\times}10^1CFU/ml$ of BGN4. Those primer sets also detected and identified BGN4 in the probiotic products containing BNG4 and fecal samples from a BGN4-fed animal model with high specificity. Our results indicate that the PCR assay from this study is an efficient tool for the simple, rapid, and reliable identification of BGN4, for which probiotic strains are known.

• Structural Engineering and Mechanics
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• 제44권3호
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• pp.289-303
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• 2012

Existing plane stress solutions for thin plates and disks have shown several qualitative features which are difficult to handle with the use of commercial numerical codes (non-existence of solutions, singular solutions, rapid growth of the plastic zone with a loading parameter). In order to understand the effect of temperature and pressure-dependency of the yield criterion on some of such features as well as on the distribution of residual stresses and strains, a semi-analytic solution for a thin hollow disk fixed to a rigid container and subject to thermal loading and subsequent unloading is derived. The material model is elastic-perfectly/plastic. The Drucker-Prager pressure-dependent yield criterion and the equation of incompressibity for plastic strains are adopted. The distribution of residual stresses and strains is illustrated for a wide range of the parameter which controls pressure-dependency of the yield criterion.

• 한국균학회지
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• 제49권3호
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• pp.285-294
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• 2021

In general, mycoviruses remain latent and rarely cause visible symptoms in fungal hosts; however, some viral infections have demonstrated abnormal mycelial growth and fruiting body development in commercial macrofungi, including Lentinula edodes. Compared to other cultivated mushrooms, L. edodes is more vulnerable to viral infections as it is still widely cultivated under near-natural conditions. In this study, we investigated whether Korean wild strains of L. edodes were infected by RNA mycoviruses that have previously been reported in other parts of the world (LeSV, LePV1, LeV-HKB, LeNSRV1, and LeNSRV2). Using specific primer sets that target the RNA-dependent RNA polymerase genes of each of the RNA mycovirus, reverse transcription-polymerase chain reaction (RT-PCR) was used to detect viral infection. Viral infection was detected in about 90% of the 112 wild strains that were collected in Korea between 1983 and 2020. Moreover, multiple infections with RNA mycoviruses were detected in strains that had normal fruiting bodies. This work contributes to our understanding of the distribution of RNA mycoviruses in Korea and the impact of multiple viral infections in a single strain of L. edodes.

• 한국수산과학회지
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• 제54권6호
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• pp.918-926
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• 2021

We isolated 28 Vibrio vulnificus strains from seawater and fisheries and investigated the positive rate of eight virulence genes. Additionally, we evaluated the susceptibility of these strains to 25 antimicrobials. The positive rates of fur, vvhA, tcp, rtxA, vcgC, viuB, vvp, and acfA were 100, 92.9, 92.9, 67.9, 64.3, 25.0, 14.3, and 7.1%, respectively. A disk diffusion susceptibility test revealed that, all the investigated strains had the highest resistance to amoxicillin and oxacillin, followed by that to streptomycin (96.4%), cefoxitin (92.9%), clindamycin (82.1%), amikacin (67.9%), vancomycin (46.4%), nalidixic acid (7.1%), penicillin G (7.1%), and ampicillin (3.6%). Moreover, they were susceptible to 10 other antimicrobials, including cefotaxime, chloramphenicol, erythromycin, gentamicin, and rifampicin. Notably, amoxicillin, oxacillin, and streptomycin had average minimum inhibitory concentrations of 132.6, 603.4, and 23.1 ㎍/mL against V. vulnificus, respectively. These observations provide new insights regarding the necessity for sanitation of commercial fisheries and can potentially, help reduce the risk posed by fisheries contaminated with bacteria resistant to antimicrobials.

• 한국식품과학회지
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• 제47권1호
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• pp.44-50
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• 2015

본 연구에서는 시판 생막걸리에서 분리한 유산균의 probiotics 특성을 연구하기 위해 내산성, 내담즙성, 장 부착능에 효능이 있는 6개 균주를 선별하여 동정하였다. 생막걸리에서 분리한 유산균을 pH 2.5의 산성 및 담즙산(0.3% oxgall) 조건에서 내산성과 내담즙성을 측정한 결과 BSM-2, BSM-3, GSM-3, TJH-1, EHJ-1, EHJ-2의 6개 균주에서 각각 $10^7$, $10^8CFU/mL$ 높은 생존률을 나타내어 우수한 내산성과 내담즙성을 확인할 수 있었다. 내산성과 내담즙성에 효능이 있는 6개 균주의 16S rDNA 분석 결과, L. plantarum (BSM-2, EHJ-1) L. casei (GSM-3, EHJ-2), L. brevis (BSM-3), P. pentosaceus (TJH-1)의 4개 group이 동정되었다. 장부착능에서는 다른 유산균에 비해 장내 부착능이 뛰어난 것으로 알려진 L. rhamnosus GG를 대조군으로 사용하였으며 HT-29 cell에 대해 6종의 유산균이 모두 장 부착능을 보였으며 L. casei(GSM-3, EHJ-2)가 가장 장 부착능이 높았다. 항산화능력은 L. plantarum BSM-2와 EHJ-1에서 각각 32.44%, 24.65%의 DPPH radical 소거능을 보였다. 시판 생막걸리에서 분리된 유산균은 다양한 식중독 원인 세균에 대하여 항균활성을 지니고 있었으며, 본 연구에서는 유산균이 생성하는 항균물질인 bacteriocin이 아닌 유산균 발효 중 젖산을 생성하면서 pH의 저하로 항균활성을 보인다는 결과를 확인할 수 있었다. Probiotics로의 기능성을 가진 6개 균주의 콜레스테롤 저하능력은 L. plantarum BSM-2와 EHJ-1에서 각각 68.82%, 56.38%의 높은 감소율을 나타내었다. 시판 생막걸리에서 분리한 유산균의 probiotic 특성을 조사해 본 결과 L. plantarum BSM-2, EHJ-1, L. brevis BSM-3, L. casei GSM-3, EHJ-2, P. pentosaceus TJH-1 모두 프로바이오틱스의 기본특성을 지니고 있어 프로바이오틱 균주로서 이용가치가 충분하다고 판단되어지며, L. plantarum BSM-2가 내산성, 내담즙성이 가장 우수한 결과를 나타내었고, 장 부착성이 우수하였으며, 뛰어난 항산화 능력과 항균력을 지니며, 콜레스테롤 저하능도 뛰어나 가장 우수한 프로바이오틱 균주라고 판단된다.

• 한국가금학회지
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• 제43권1호
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• pp.1-14
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• 2016

Prediction of growth patterns of commercial chicken strains is important. It can provide visual assessment of growth as function of time and prediction body weight (BW) at a specific age. The aim of current study is to compare the three nonlinear functions (i.e., Logistic, Gompertz, and von Betalanffy) for modeling the growth of twenty five commercial Korean native chicken (KNC) strains reared under a battery cage system until 32 weeks of age and to evaluate the three models with regard to their ability to describe the relationship between BW and age. A clear difference in growth pattern among 25 strains were observed and classified in to the groups according to their growth patterns. The highest and lowest estimated values for asymptotic body weight (C) for 3H and 5W were given by von Bertalanffy and Logistic model 4629.7 g for 2197.8 g respectively. The highest estimated parameter for maturating rate (b) was given by Logistic model 0.249 corresponds to the 2F and lowest in von Bertalanffy model 0.094 for 4Y. According to the coefficient of determination ($R^2$) and mean square of error (MSE), Gompertz and von Bertalanffy models were suitable to describe the growth of Korean native chicken. Moreover, von Bertalannfy model was well described the most of KNC growth with biologically meaningful parameter compared to Gompertz model.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.579-584
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• 2008

A commercial chromogenic agar medium (DFI) was supplemented with glucose (mDFI) to enhance the specificity of Enterobacter sakazakii (E. sakazakit) detection. Escherichia vulneris (E. vulneris), a putative false-positive strain on the DFI medium, produces ${\alpha}$-glucosidase. The enzyme ${\alpha}$-glucosidase hydrolyzes a substrate, 5-bromo-4-chloro-3-indolyl-${\alpha}$, D-glucopyranoside $(X{\alpha}Glc)$, producing green colonies. E. sakazakii strains produced green colonies on both DFI and mDFI agar, whereas E. vulneris produced green colonies on DFI agar but small white colonies on mDFI agar. E. sakazakii and E. vulneris were also readily differentiated by colony color when the mixed culture of the two strains was plated on mDFI agar and incubated for 24 h at $37^{\circ}C$. The results indicate that the selectivity of the commercial chromogenic agar medium could be improved by a simple supplementation with glucose.

• 한국수산과학회지
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• 제49권6호
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• pp.792-799
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• 2016

We isolated seven tryptamine-producing bacteria from commercial salted and fermented sand lance (Ammodytes personatus) sauces using an L-tryptophan decarboxylating medium. These tryptamine-producing bacteria, identified using an API kit and 16S rRNA analysis, included Lysinibacillus xylanilyticus (one strain), Lysinibacillus fusiformis (four strains), and Staphylococcus epidermidis (two strains). Lysinibacillus spp. produced the highest levels of tryptamine in culture broth containing 0.5% L-tryptophan, compared with 1.0% and 2.0% preparations. After 72 h of incubation, Staphylococcus epidermidis produced the highest levels of tryptamine ($60.50{\mu}g/mL$ and $664.86{\mu}g/mL$) in culture broth containing 2.0% L-tryptophan. While Lysinibacillus spp. comprised the dominant tryptamine-producing bacteria in sand lance sauces, Staphylococcus epidermidis also showed high tryptamine-producing activity. This is the first report on the isolation and identification of tryptamine-producing bacteria in sand lance sauces.

• 환경위생공학
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• 제16권2호
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• pp.79-90
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• 2001

Commercial liquid seeds are used for supplying active microbial flora to organic wastewater treatment plants of high feed-to-microorganism ratio and to maintain optimal microbial condition during unsteady state operation of the biological wastewater treatment plant. In addition to bacterial cells, the liquid weeds contain various additives for special purposes as well as organic substrates for energy supply. The additives give physical stability for the maintenance of microbial decomposition activity and ability to control the overgrowth of seed strains. In this work, the effects of addition of two kinds of typical substrate additives, poly aluminum chloride(PAC) and poly aluminum sulfate(PAS) on the consitutional total cell counts(CFU/ml) of four kinds of reorganization liquid seeds(RLS I, RLS II, RLS III and RLS IV) were studied experimentally. The addition of PAC and PAS gave negative effect on TCC constitution for the four seeds studied.

• 대한수의학회지
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• 제64권1호
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• pp.4.1-4.5
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• 2024

In this study, almost complete genomic sequences of porcine parvovirus (PPV)1 and PPV4 circulating in commercial pig farms in South Korea were obtained and analyzed. Important mutations that may be precursors to host changes, such as premature stop codons of PPV1 and frameshift mutations of PPV4, were observed in these sequences. A 27a-like strain of PPV1, known to show a lack of cross- neutralization against existing commercial vaccine strains, was identified by phylogenetic analysis. Given the active genetic evolution, the additional precursors to host changes and emerging new genotypes of PPVs need to be monitored through continuous sampling and genetic analysis.