• 한국식품과학회지
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• 제20권1호
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• pp.23-27
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• 1988

Bacillus subtilis의 생육 억제에 미치는 보존료의 병용효과 및 식염과의 상승효과를 조사하기 위하여 tryptone glucose-yeast extract 액체배지에 potassium sorbate와 sodiun bnzoate를 각각 최고허용농도의 1/2인 0.1%, 0.03%로 처리하고 이에 미생물의 내염성 기준도인 2% 식염을 첨가하여 진탕배양(4시간) 또는 정치배양 (4일)하면서 생육 상태를 조사한 결과, 두 보존료의 상승효과가 정치 및 진탕배양에서 모두 나타나지 않았으나 potassium sorbate와 식염의 병용처리구에서는 상승효과가 현저하게 나타났다.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.500-506
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• 2017

To investigate the potential applications of bacterial heme, aminolevulinic acid synthase (HemA) was expressed in a Corynebacterium glutamicum HA strain that had been adaptively evolved against oxidative stress. The red pigment from the constructed strain was extracted and it exhibited the typical heme absorbance at 408 nm from the spectrum. To investigate the potential of this strain as an iron additive for swine, a prototype feed additive was manufactured in pilot scale by culturing the strain in a 5 ton fermenter followed by spray-drying the biomass with flour as an excipient (biomass: flour = 1:10 (w/w)). The 10% prototype additive along with regular feed was supplied to a pig, resulting in a 1.1 kg greater increase in weight gain with no diarrhea in 3 weeks as compared with that in a control pig that was fed an additive containing only flour. To verify if C. glutamicum-synthesized heme is a potential electron carrier, lactic acid bacteria were cultured under aerobic conditions with the extracted heme. The biomasses of the aerobically grown Lactococcus lactis, Lactobacillus rhamosus, and Lactobacillus casei were 97%, 15%, and 4% greater, respectively, than those under fermentative growth conditions. As a potential preservative, cultures of the four strains of lactic acid bacteria were stored at $4^{\circ}C$ with the extracted heme and living lactic acid bacterial cells were counted. There were more L. lactis and L. plantarum live cells when stored with heme, whereas L. rhamosus and L. casei showed no significant differences in live-cell numbers. The potential uses of the heme from C. glutamicum are further discussed.

• Molecular & Cellular Toxicology
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• 제3권1호
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• pp.53-59
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• 2007

This study was conducted to evaluate the mutagenic potential of dimethyl isophthalate (DMIP) using Ames bacterial reverse mutation test, chromosomal aberration test and mouse lymphoma $tk^{+/-}$ gene assay. As results, in Ames bacterial reversion assay, DMIP was tested up to the concentration of 5,000 ${\mu}g$/plate and did not induce mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli WP2uvrA with or without metabolic activation (S9 mix). Using cytotoxicity test, the maximal doses of DMIP for chromosomal aberration assay were determined at 1,250 ${\mu}g/mL$, which was a minimum precipitation concentration ($IC_{50}>1,940\;{\mu}g/mL$ or 10 mM) and at 155 ${\mu}g/mL$ ($IC_{50}:155\;{\mu}g/mL$) in the presence and the absence, respectively, of S9 mix. DMIP in the presence of S9 mix induced statistically significant (P<0.001) increases in the number of cells with chromosome aberrations at the dose levels of over 250 ${\mu}g/mL$, when compared with the negative control. However, DMIP in the absence of S9 mix did not caused significant induction in chromosomal aberrant cells. In MLA, DMIP at the dose range of 242.5-1,940 ${\mu}g/mL$ in the presence of S9 mix induced statistically significant increases in mutation frequencies related to small colony growth, whereas any significant mutation frequency was not observed in absence of S9 mix. From these results, it is conclusively suggested that dimethyl isophthalate may be a clastogen rather than a point mutagen.

• The Plant Pathology Journal
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• 제29권2호
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• pp.182-192
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• 2013

Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90-166, in tobacco. Since S. marcescens 90-166 produces at least three QS signals, QS-mediated ISR in strain 90-166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90-166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90-166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90-166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90-166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90-166.

• 한국미생물·생명공학회지
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• 제44권4호
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• pp.535-539
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• 2016

제주도 넙치 양식장에서 주로 발생하는 어류질병세균인 S. parauberis, S. iniae, E. tarda에 대한 피해를 줄이고자 갈륨을 이용하여 어류질병세균을 억제하고자 한다. 본 연구진은 Sp, Si, Et의 생육도와 biofilm 형성능을 확인하였으며, 세균의 성장도와 biofilm 형성능간의 특정한 패턴은 없었으며 세균의 성장도가 높다 하더라도 biofilm을 활발히 형성하지 않음을 알 수 있었다. 어류질병세균이 형성하는 biofilm을 저해하기 위해 갈륨을 2.0, 4.0, 8.0 mg/ml로 첨가하여 저해능을 확인한 결과 72시간째 biofilm의 형성이 크게 저해되는 것을 확인하였다. 또한 biofilm을 저해하는 동시에 균주의 사멸능을 확인하기 위해 resazurin assay와 propidium iodide를 이용하여 염색한 결과 갈륨의 농도에 따라 균주의 사멸이 증가하는 것을 확인하였다. 이에 따라 in vitro 상에서 갈륨이 어류질병세균의 biofilm을 억제하는 동시에 균주를 사멸시키는 물질로서 가치가 있다고 사료된다.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.987-996
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• 2018

Bacterial programmed cell death is regulated by the toxin-antitoxin (TA) system. YhaV (toxin) and Pr1F (antitoxin) have been recently identified as a type II TA system in Escherichia coli. YhaV homologs have conserved active residues within the C-terminus, and to characterize the function of this region, we purified native YhaV protein (without denaturing) and constructed YhaV proteins of varying lengths. Here, we report a new low-temperature method of purifying native YhaV, which is notable given the existing challenges of purifying this highly toxic protein. The secondary structures and thermostability of the purified native protein were characterized and no significant structural destruction was observed, suggesting that the observed inhibition of cell growth in vivo was not the result of structural protein damage. However, it has been reported that excessive levels of protein expression may result in protein misfolding and changes in cell growth and mRNA stability. To exclude this possibility, we used an [$^{35}S$]-methionine prokaryotic cell-free protein synthesis system in vitro in the presence of purified YhaV, and two C-terminal truncated forms of this protein (YhaV-L and YhaV-S). Our results suggest that the YhaV C-terminal region is essential for mRNA interferase activity, and the W143 or H154 residues may play an analogous role to Y87 of RelE.

• 한국토양비료학회지
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• 제37권1호
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• pp.41-45
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• 2004

충북지역의 근권 토양으로부터 선발한 인산가용화 균인 Pantoea agglomeraans와 인광석을 복합처리하여 벼(Oryza sativa L.)의 생육 및 인산 흡수량에 미치는 영향을 온실내에서 실험하였다. 본 실험은, 종자에 박테리아를 적용시킨 것(bactenzation), 독립 세포 및 고정화된 세포(immobilized cell)를 접종시킨 후, 인광석 1 g과 2.5 g을 각각 시비한 6처리구와 무처리구로 나누어 비교 실험하였다. 인산가용화균을 접종한 처리구가 무처리구에 비하여 벼의 생육 및 인산 흡수량을 증대하는 경향을 나타냈으며, 특히 1 g의 인광석과 고정화된 Pantoea agglomerans를 접종한 처리구에서 다른 처리구들에 비해 가장 우수한 결과를 나타내었다. Pot 충진물내의 유효인산 농도 또한 미생물 접종 처리구에서 증가하였으며, 벼에 흡수된 전인산량과 정의 상관관계가 성립함을 알 수 있었다.

• 한국축산식품학회지
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• 제36권2호
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• pp.262-266
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• 2016

This study evaluated the growth kinetics of Salmonella spp. in processed meat products formulated with low sodium nitrite (NaNO₂). A 5-strain mixture of Salmonella spp. was inoculated on 25-g samples of sausages formulated with sodium chloride (NaCl) (1.0%, 1.25%, and 1.5%) and NaNO₂ (0 and 10 ppm) followed by aerobic or vacuum storage at 10℃ and 15℃ for up to 816 h or 408 h, respectively. The bacterial cell counts were enumerated on xylose lysine deoxycholate agar, and the modified Gompertz model was fitted to the Salmonella cell counts to calculate the kinetic parameters as a function of NaCl concentration on the growth rate (GR; Log CFU/g/h) and lag phase duration (LPD; h). A linear equation was then fitted to the parameters to evaluate the effect of NaCl concentration on the kinetic parameters. The GR values of Salmonella on sausages were higher (p<0.05) with 10 ppm NaNO₂ concentration than with 0 ppm NaNO₂. The GR values of Salmonella decreased (p<0.05) as NaCl concentration increased, especially at 10℃. This result indicates that 10 ppm NaNO₂ may increase Salmonella growth at low NaCl concentrations, and that NaCl plays an important role in inhibiting Salmonella growth in sausages with low NaNO₂.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1029-1039
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• 2024

This study explores beneficial bacteria isolated from the roots and rhizosphere soil of Khao Rai Leum Pua Phetchabun rice plants. A total of 315 bacterial isolates (KK001 to KK315) were obtained. Plant growth-promoting traits (phosphate solubilization and indole-3-acetic acid (IAA) production), and antimicrobial activity against three rice pathogens (Curvularia lunata NUF001, Bipolaris oryzae 2464, and Xanthomonas oryzae pv. oryzae) were assessed. KK074 was the most prolific in IAA production, generating 362.6 ± 28.0 ㎍/ml, and KK007 excelled in tricalcium phosphate solubilization, achieving 714.2 ± 12.1 ㎍/ml. In antimicrobial assays using the dual culture method, KK024 and KK281 exhibited strong inhibitory activity against C. lunata, and KK269 was particularly effective against B. oryzae. In the evaluation of antimicrobial metabolite production, KK281 and KK288 exhibited strong antifungal activities in cell-free supernatants. Given the superior performance of KK281, taxonomically identified as Bacillus sp. KK281, it was investigated further. Lipopeptide extracts from KK281 had significant antimicrobial activity against C. lunata and a minimum inhibitory concentration (MIC) of 3.1 mg/ml against X. oryzae pv. oryzae. LC-ESI-MS/MS analysis revealed the presence of surfactin in the lipopeptide extract. The crude extract was non-cytotoxic to the L-929 cell line at tested concentrations. In conclusion, the in vitro plant growth-promoting and disease-controlling attributes of Bacillus sp. KK281 make it a strong candidate for field evaluation to boost plant growth and manage disease in upland rice.

• 한국식품위생안전성학회지
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• 제38권1호
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• pp.19-25
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• 2023

비가열 닭고기 분쇄육의 제조 시 향신료의 첨가에 의한 세균의 증식 억제 효과에 대하여 연구하였다. 닭가슴살 분쇄육의 일반성분은 수분 72.98±0.15%, 조단백질 23.37±0.46%, 조지방 1.00±0.03%, 조회분 1.90±0.03%였다. 향신료 첨가에 의한 미생물 증식 억제 효과는 로즈마리 > 마늘 > 겨자 순이었으며, 첨가량이 증가할수록 억제 효과가 커졌다. 닭고기 분쇄육의 일반세균 및 대장균 증식 억제를 나타내는 향신료의 최적 첨가 농도는 로즈마리 2%, 마늘 4%, 겨자 1.2%였다. 일반세균 및 대장균에 대한 증식 억제 효과는 단독 및 혼합 첨가 시 저장기간 동안 기간별로 차이가 있었고, 저장 9일째 억제 효과는 MixA(97.4%) > 로즈마리(96.9%) > MixB(96.3%) > 마늘(53.7%) > 겨자(33.3%) 순이었다. 닭고기 분쇄육에 살균마늘과 비살균마늘을 첨가하여 비교했을 때 일반세균 수는 살균마늘 처리구가 비살균마늘 처리구에 비해 초기 2.6-3.0 log CFU/g, 9일째 2.4-3.2 log CFU/g 정도 낮았고, 저장기간이 경과할수록 그 수가 감소하였다. 비살균마늘 처리구는 대조구보다 높은 일반세균 수를 나타냈으며, 저장기간이 경과할수록 증가하는 경향을 나타냈다. 대장균 수의 경우 살균마늘 처리구가 비살균마늘 처리구에 비해 저장 0일째 0.4-1.0 log CFU/g, 9일째 0.5-1.5 log CFU/g 정도 낮았으며, 저장기간의 경과에 따른 변화는 일반세균 수와 비슷한 경향을 나타냈다. 결론적으로 로즈마리, 마늘, 겨자의 다양한 혼합적용에 의해 닭고기 분쇄육 제품의 미생물적 안전성이 향상되었다.