• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.476-482
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• 2002

Methanol dehydrogenase (MDH) and c-type cytochromes from marine methanol-oxidizing bacterium, Methylophaga sp. MP, were purified and characterized. The native MDH had a molecular mass of 148 kDa and its isoelectric point was 5.5. Two c-type cytochromes, $c_L\;and\;c_H$, were found, and their isoelectric points were 3.4 and 8.0, respectively. The purified MDH had higher thermal stability than that of the other soil methylotrophic bacteria. The electron flow rate from MDH to cytochrome $c_L$was higher than that from MDH to cytochrome $c_H$, indicating that the physiological primary electron acceptor for MDH is cytochrome $c_L$. The electron transfer from MDH to phenazine ethosulfate (PES, artificial electron acceptor) in the two dye (PES/DCPIP)-linked assay system was not inhibited by NaCl, whereas the electron flow from MDH to cytochrome $c_L$ in the cytochrome/DCPIP-linked assay system was suppressed significantly by NaCl. Metal chelating agents such as EDTA showed the same effects on the MDH activity.

• 대한치과기공학회지
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• 제22권1호
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• pp.145-152
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• 2000

In order to select an effective antibiotic substance against oral resident bacteria, we were isolated from soil and texonomically analyzed. Seven hundred and eighteen strains were isolated on humic acid- vitamin agar(HV agar) and 220 strains were on methanol medium from three each paddy forest, field and riverside soil samples. So, during the screening of antibiotics from soil, we isolated microorganisms showing powerful antagonistic activity against oral resident bacteria. Microorganism was tested against 25 strains of bacteria, yeast and fungi. Among them, No. 248 strain exhibited the most strongly growth inhibition. So, the taxonomical analysis the isolated strain was found to be unknown Actinomyces sp. and was named No 248. A production of the antibiotics from No. 248 begins at the early exponential phase developed at the 72th hour under the optinum conditions. The property of No. 248 antimicrobial compound was very stable under acid(pH 3.0) and alkali(pH 10.0) treatment, but it was instable in heat treatment at $120^{\circ}C$. For the improvement of antibiotic activity, two mutants were isolated from strain No. 248 by the treatment of mutagenic agents, NTG and hydroxylamine. As a result, the mutant strains excreted the potent antibiotics to inhibit the growth of Candida albicans.

• 미생물학회지
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• 제46권3호
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• pp.286-290
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• 2010

C-1화합물은 고염분성 환경의 혐기적인 퇴적층에서 관찰되며, 이 퇴적층의 표면과 수면에는 호기성 메틸영양미생물의 잠재적인 서식지가 된다. 염전과 갯벌에서 채취한 토양 시료를 접종원으로 하여 메탄올을 탄소원과 에너지원으로 공급하고 염분농도에 따라 계대배양한 후 메탄올 산화 세균 성장 조건을 살펴 본 결과, 메탄올 산화 세균이 성장 할 수 있는 염분의 최대 농도는 20% 조건이었다. 변성 구배 젤 전기영동 (Denaturing gel gradient electrophoresis)을 이용하여 농화배양액 내 미생물 군집구조를 분석한 결과, 메탄올 산화 미생물인 Methylophaga 관련 세균이 우점하는 것으로 나타났다. 정량 PCR결과 고세균이 세균의 1-10%로 존재하는 것으로 나타났다. 세균용 항생제 실험결과, 메탄올 산화가 억제되어 고세균이 메탄올 산화에 관여하지 않는다는 것을 추정할 수 있었다. 이번 연구를 통해, 메틸영양세균이 고염분환경(염분 농도 20%까지)에서도 C-1 화합물을 산화할 수 있음을 확인 할 수 있었다.

• Journal of Microbiology
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• 제38권4호
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• pp.209-217
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• 2000

Mycobacterium sp. strain JCl DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in mast methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed, in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JCl. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly Of indirectly in Mycobacterium sp. JCl.

• 한국토양비료학회지
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• 제42권4호
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• pp.317-322
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• 2009

농업유용미생물을 이용한 원예 및 채소작물의 건전 유묘 생산을 위하여 본 연구에서는 growth pouch 실험을 통하여 6가지 식물생육촉진 미생물을 접종하여 작물의 초기 뿌리 생장에 미치는 영향을 살펴 보았다. 본 실험에 사용한 6가지 균주는 Methylobacterium oryzae CBMB20, Methylobacterium phyllosphaerae CBMB27, Methylobacterium suomiense CBMB120, Methylobacterium strains CBMB12, CBMB15와 CBMB17이었다. 대조구와 비교했을 CBMB12, CBMB17, 및 CBMB20접종은 상추 초기 뿌리 생육에 유의성있는 효과를 보였고, CBMB102접종은 배추 초기 뿌리 생육에 유의성있는 효과를, CBMB27접종은 토마토의 초기 뿌리 생육에 유의성있는 효과를 보였다. 또한 Methylobacterium suomiense CBMB120접종은 오이, 토마토, 배추, 그리고 Methylobacterium strain CBMB12접종은 고추의 뿌리 초기 생장을 크게 촉진시켰음을 알 수 있었다. 위의 결과를 통하여 실험한 균주들을 각각의 작물 육묘 포트에 처리할 때에도 유묘의 생장속도를 촉진 시킬수 있음을 예상할 수 있다.

• 미생물학회지
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• 제40권4호
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• pp.348-354
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• 2004

사람의 모유에 많이 함유된 human lactoferrin(hLF)은 항균 및 항 바이러스 작용이 있는 것으로 보고되고 있다. 본 연구에서는 hLf를 메탄올자화 효모인 Pichia pastoris에 cloning하고 그 발현을 RT-PCR, Northern blotting, SDS-PAGE및 Western blotting으로 확인하였다. 그 결과 2.1 kb의 hLf 유전자가 P.pastoris의 염색체 DNA로 끼어들어가 안정적으로 hLf를 발현하였다. 이 재조합 P.pastotis로부터 hLf를 포함하는 세포 추출액을 얻어 항균 작용을 연구하였다. 발현된 재조합 hLf는 Staphylococcus aureus, Micrococcus flavus 등의 그람 양성균에 대해 강력한 항균작용을 보일 뿐만 아니라 그람 음성 동물성 병원균인 Pseudomonas fluorescens ID 9631, E. coli ATCC8739, 25922,35 등과 Salmonella typhimurium 114,115 등 다양한 균에 대해서도 강력한 항균작용을 보였다. 이는 재조합 hLf가 생물학적 활성이 있다는 것을 보여준다.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1622-1628
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• 2006

Bacteria from the Methylobacterium genus, called pink-pigmented facultative methylotrophic bacteria (PPFMs), are common inhabitants of plants, potentially dominating the phyllosphere population, and are also encountered in the rhizosphere, seeds, and other parts of plants, being versatile in nature. The consistent success of the Methylobacterium plant association relies on methylotrophy, the ability to utilize the one-carbon compound methanol emitted by plants. However, the efficiency of Methylobacterium in plant growth promotion could be better exploited and thus has attracted increasing interest in recent years. Accordingly, the present study investigated the inoculation effects of Methylobacterium sp. strains CBMB20 and CBMB 110 on seed imbibition to tomato and red pepper on the growth and accumulation of phytohormone levels under gnotobiotic conditions. Seeds treated with the Methylobacterium strains showed a significant increase in root length when compared with either the uninoculated control or Methylobacterium extorquens $miaA^-$ knockout mutanttreated seeds. Extracts of the plant samples were used for indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), and dihydrozeatin riboside (DHZR) assays by immunoanalysis. The treatment with Methylobacterium sp. CBMB20 or CBMB 110 produced significant increases in the accumulation of IAA and the cytokinins t-ZR and DHZR in the red pepper extracts, whereas no IAA was detected in the tomato extracts, although the cytokinin concentrations were significantly increased. Therefore, this study proved that the versatility of Methylobacterium as a plant-growth promoting bacteria could be better exploited.

• 한국토양비료학회지
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• 제45권1호
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• pp.37-42
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• 2012

Improvement of plant growth by Methylotrophic bacteria can be influenced through alterations in growth modulating enzymes or hormones, especially by decreasing ethylene levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or by production of indole-3-acetic acid (IAA). In this study, the effect of seven strains of Methylobacterium on seedling ethylene emission of tomato and red pepper plants was evaluated under greenhouse condition. Ethylene emission was lowest in Methylobacterium oryzae CBMB20 inoculated tomato plants and CBMB110 inoculated red pepper plants at 47 days after sowing (DAS). However, at 58 DAS all inoculated plants showed almost similar pattern of ethylene emission. Methylobacterium inoculated tomato and red pepper plants showed significantly less ethylene emission compared to control. Our results demonstrated that Methylobacterium spp. inoculation promotes plant growth due to the reduction of ethylene emission and therefore can be potentially used in sustainable agriculture production systems.

• 미생물학회지
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• 제38권4호
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• pp.209-209
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• 2002

Mycobacterium sp. strain JCl DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in mast methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed, in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JCl. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly Of indirectly in Mycobacterium sp. JCl.

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1706-1715
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• 2018

Several non-methylotrophic bacteria have been reported to improve the growth and activity of methanotrophs; however, their interactions remain to be elucidated. We investigated the interaction between Methylocystis sp. M6 and Microbacterium sp. NM2. A batch co-culture experiment showed that NM2 markedly increased the biomass and methane removal of M6. qPCR analysis revealed that NM2 enhanced both the growth and methane-monooxygenase gene expression of M6. A fed-batch experiment showed that co-culture was more efficient in removing methane than M6 alone (28.4 vs. $18.8{\mu}mol{\cdot}l^{-1}{\cdot}d^{-1}$), although the biomass levels were similar. A starvation experiment for 21 days showed that M6 population remained stable while NM2 population decreased by 66% in co-culture, but the results were opposite in pure cultures, indicating that M6 may cross-feed growth substrates from NM2. These results indicate that M6 apparently had no negative effect on NM2 when M6 actively proliferated with methane. Interestingly, a batch experiment involving a dialysis membrane indicates that physical proximity between NM2 and M6 is required for such biomass and methane removal enhancement. Collectively, the observed interaction is beneficial to the methanotroph but adversely affects the non-methylotroph; moreover, it requires physical proximity, suggesting a tight association between methanotrophs and non-methylotrophs in natural environments.